[PATCH v2 00/33] Separate struct slab from struct page

[PATCH v2 00/33] Separate struct slab from struct page

[Vlastimil Babka]

Folks from non-slab subsystems are Cc'd only to patches affecting them, and
this cover letter.

Series also available in git, based on 5.16-rc3:
https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2

The plan: as my SLUB PREEMPT_RT series in 5.15, I would prefer to go again with
the git pull request way of eventually merging this, as it's also not a small
series. I will thus reply to this mail with asking to include my branch in
linux-next.

As stated in the v1/RFC cover letter, I wouldn't mind to then continue with
maintaining a git tree for all slab patches in general. It was apparently
already done that way before, by Pekka:
https://lore.kernel.org/linux-mm/alpine.DEB.2.00.1107221108190.2996@tiger/

Changes from v1/RFC:
https://lore.kernel.org/all/20211116001628.24216-1-vbabka@suse.cz/
- Added virt_to_folio() and folio_address() in the new Patch 1.
- Addressed feedback from Andrey Konovalov and Matthew Wilcox (Thanks!)
- Added Tested-by: Marco Elver for the KFENCE parts (Thanks!)

Previous version from Matthew Wilcox:
https://lore.kernel.org/all/20211004134650.4031813-1-willy@infradead.org/

LWN coverage of the above:
https://lwn.net/Articles/871982/

This is originally an offshoot of the folio work by Matthew. One of the more
complex parts of the struct page definition are the parts used by the slab
allocators. It would be good for the MM in general if struct slab were its own
data type, and it also helps to prevent tail pages from slipping in anywhere.
As Matthew requested in his proof of concept series, I have taken over the
development of this series, so it's a mix of patches from him (often modified
by me) and my own.

One big difference is the use of coccinelle to perform the relatively trivial
parts of the conversions automatically and at once, instead of a larger number
of smaller incremental reviewable steps. Thanks to Julia Lawall and Luis
Chamberlain for all their help!

Another notable difference is (based also on review feedback) I don't represent
with a struct slab the large kmalloc allocations which are not really a slab,
but use page allocator directly. When going from an object address to a struct
slab, the code tests first folio slab flag, and only if it's set it converts to
struct slab. This makes the struct slab type stronger.

Finally, although Matthew's version didn't use any of the folio work, the
initial support has been merged meanwhile so my version builds on top of it
where appropriate. This eliminates some of the redundant compound_head()
being performed e.g. when testing the slab flag.

To sum up, after this series, struct page fields used by slab allocators are
moved from struct page to a new struct slab, that uses the same physical
storage. The availability of the fields is further distinguished by the
selected slab allocator implementation. The advantages include:

- Similar to folios, if the slab is of order > 0, struct slab always is
  guaranteed to be the head page. Additionally it's guaranteed to be an actual
  slab page, not a large kmalloc. This removes uncertainty and potential for
  bugs.
- It's not possible to accidentally use fields of the slab implementation that's
  not configured.
- Other subsystems cannot use slab's fields in struct page anymore (some
  existing non-slab usages had to be adjusted in this series), so slab
  implementations have more freedom in rearranging them in the struct slab.

Matthew Wilcox (Oracle) (16):
  mm: Split slab into its own type
  mm: Add account_slab() and unaccount_slab()
  mm: Convert virt_to_cache() to use struct slab
  mm: Convert __ksize() to struct slab
  mm: Use struct slab in kmem_obj_info()
  mm: Convert check_heap_object() to use struct slab
  mm/slub: Convert detached_freelist to use a struct slab
  mm/slub: Convert kfree() to use a struct slab
  mm/slub: Convert print_page_info() to print_slab_info()
  mm/slub: Convert pfmemalloc_match() to take a struct slab
  mm/slob: Convert SLOB to use struct slab
  mm/kasan: Convert to struct folio and struct slab
  zsmalloc: Stop using slab fields in struct page
  bootmem: Use page->index instead of page->freelist
  iommu: Use put_pages_list
  mm: Remove slab from struct page

Vlastimil Babka (17):
  mm: add virt_to_folio() and folio_address()
  mm/slab: Dissolve slab_map_pages() in its caller
  mm/slub: Make object_err() static
  mm/slub: Convert __slab_lock() and __slab_unlock() to struct slab
  mm/slub: Convert alloc_slab_page() to return a struct slab
  mm/slub: Convert __free_slab() to use struct slab
  mm/slub: Convert most struct page to struct slab by spatch
  mm/slub: Finish struct page to struct slab conversion
  mm/slab: Convert kmem_getpages() and kmem_freepages() to struct slab
  mm/slab: Convert most struct page to struct slab by spatch
  mm/slab: Finish struct page to struct slab conversion
  mm: Convert struct page to struct slab in functions used by other
    subsystems
  mm/memcg: Convert slab objcgs from struct page to struct slab
  mm/kfence: Convert kfence_guarded_alloc() to struct slab
  mm/sl*b: Differentiate struct slab fields by sl*b implementations
  mm/slub: Simplify struct slab slabs field definition
  mm/slub: Define struct slab fields for CONFIG_SLUB_CPU_PARTIAL only
    when enabled

 arch/x86/mm/init_64.c          |    2 +-
 drivers/iommu/amd/io_pgtable.c |   59 +-
 drivers/iommu/dma-iommu.c      |   11 +-
 drivers/iommu/intel/iommu.c    |   89 +--
 include/linux/bootmem_info.h   |    2 +-
 include/linux/iommu.h          |    3 +-
 include/linux/kasan.h          |    9 +-
 include/linux/memcontrol.h     |   48 --
 include/linux/mm.h             |   12 +
 include/linux/mm_types.h       |   38 +-
 include/linux/page-flags.h     |   37 -
 include/linux/slab.h           |    8 -
 include/linux/slab_def.h       |   16 +-
 include/linux/slub_def.h       |   29 +-
 mm/bootmem_info.c              |    7 +-
 mm/kasan/common.c              |   27 +-
 mm/kasan/generic.c             |    8 +-
 mm/kasan/kasan.h               |    1 +
 mm/kasan/quarantine.c          |    2 +-
 mm/kasan/report.c              |   13 +-
 mm/kasan/report_tags.c         |   10 +-
 mm/kfence/core.c               |   17 +-
 mm/kfence/kfence_test.c        |    6 +-
 mm/memcontrol.c                |   43 +-
 mm/slab.c                      |  455 ++++++-------
 mm/slab.h                      |  322 ++++++++-
 mm/slab_common.c               |    8 +-
 mm/slob.c                      |   46 +-
 mm/slub.c                      | 1164 ++++++++++++++++----------------
 mm/sparse.c                    |    2 +-
 mm/usercopy.c                  |   13 +-
 mm/zsmalloc.c                  |   18 +-
 32 files changed, 1317 insertions(+), 1208 deletions(-)

-- 
2.33.1

[PATCH v2 01/33] mm: add virt_to_folio() and folio_address()

[Vlastimil Babka]

These two wrappers around their respective struct page variants will be useful
in the following patches.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 include/linux/mm.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index a7e4a9e7d807..4a6cf22483da 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -863,6 +863,13 @@ static inline struct page *virt_to_head_page(const void *x)
 	return compound_head(page);
 }
 
+static inline struct folio *virt_to_folio(const void *x)
+{
+	struct page *page = virt_to_page(x);
+
+	return page_folio(page);
+}
+
 void __put_page(struct page *page);
 
 void put_pages_list(struct list_head *pages);
@@ -1753,6 +1760,11 @@ void page_address_init(void);
 #define page_address_init()  do { } while(0)
 #endif
 
+static inline void *folio_address(const struct folio *folio)
+{
+	return page_address(&folio->page);
+}
+
 extern void *page_rmapping(struct page *page);
 extern struct anon_vma *page_anon_vma(struct page *page);
 extern pgoff_t __page_file_index(struct page *page);
-- 
2.33.1

Re: [PATCH v2 01/33] mm: add virt_to_folio() and folio_address()

[Johannes Weiner]

On Wed, Dec 01, 2021 at 07:14:38PM +0100, Vlastimil Babka wrote:
> These two wrappers around their respective struct page variants will be useful
> in the following patches.
> 
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

Slight reviewer preference: introduce helpers when they're first used,
as it's a little easier to understand the application without having
to chase new folio_address() -> new slab_address() -> first user of
slab_address() through the patchset.

Re: [PATCH v2 01/33] mm: add virt_to_folio() and folio_address()

[Vlastimil Babka]

On 12/14/21 15:20, Johannes Weiner wrote:
> On Wed, Dec 01, 2021 at 07:14:38PM +0100, Vlastimil Babka wrote:
>> These two wrappers around their respective struct page variants will be useful
>> in the following patches.
>> 
>> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> 
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>

Thanks!

> Slight reviewer preference: introduce helpers when they're first used,
> as it's a little easier to understand the application without having
> to chase new folio_address() -> new slab_address() -> first user of
> slab_address() through the patchset.

Yeah would normally do that but with the current folio work going on there
was a chance the helpers would be useful to somebody else too and
cherry-picking a patch that adds them without user is simpler. And indeed
Matthew just asked about virt_to_folio() few days ago :)

[PATCH v2 02/33] mm/slab: Dissolve slab_map_pages() in its caller

[Vlastimil Babka]

The function no longer does what its name and comment suggests, and just sets
two struct page fields, which can be done directly in its sole caller.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slab.c | 15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index ca4822f6b2b6..381875e23277 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2546,18 +2546,6 @@ static void slab_put_obj(struct kmem_cache *cachep,
 	set_free_obj(page, page->active, objnr);
 }
 
-/*
- * Map pages beginning at addr to the given cache and slab. This is required
- * for the slab allocator to be able to lookup the cache and slab of a
- * virtual address for kfree, ksize, and slab debugging.
- */
-static void slab_map_pages(struct kmem_cache *cache, struct page *page,
-			   void *freelist)
-{
-	page->slab_cache = cache;
-	page->freelist = freelist;
-}
-
 /*
  * Grow (by 1) the number of slabs within a cache.  This is called by
  * kmem_cache_alloc() when there are no active objs left in a cache.
@@ -2621,7 +2609,8 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep,
 	if (OFF_SLAB(cachep) && !freelist)
 		goto opps1;
 
-	slab_map_pages(cachep, page, freelist);
+	page->slab_cache = cachep;
+	page->freelist = freelist;
 
 	cache_init_objs(cachep, page);
 
-- 
2.33.1

[PATCH v2 03/33] mm/slub: Make object_err() static

[Vlastimil Babka]

There are no callers outside of mm/slub.c anymore.

Move freelist_corrupted() that calls object_err() to avoid a need for forward
declaration.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 include/linux/slub_def.h |  3 ---
 mm/slub.c                | 30 +++++++++++++++---------------
 2 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 0fa751b946fa..1ef68d4de9c0 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -156,9 +156,6 @@ static inline void sysfs_slab_release(struct kmem_cache *s)
 }
 #endif
 
-void object_err(struct kmem_cache *s, struct page *page,
-		u8 *object, char *reason);
-
 void *fixup_red_left(struct kmem_cache *s, void *p);
 
 static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
diff --git a/mm/slub.c b/mm/slub.c
index a8626825a829..98bf50c1c145 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -822,20 +822,6 @@ static void slab_fix(struct kmem_cache *s, char *fmt, ...)
 	va_end(args);
 }
 
-static bool freelist_corrupted(struct kmem_cache *s, struct page *page,
-			       void **freelist, void *nextfree)
-{
-	if ((s->flags & SLAB_CONSISTENCY_CHECKS) &&
-	    !check_valid_pointer(s, page, nextfree) && freelist) {
-		object_err(s, page, *freelist, "Freechain corrupt");
-		*freelist = NULL;
-		slab_fix(s, "Isolate corrupted freechain");
-		return true;
-	}
-
-	return false;
-}
-
 static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
 {
 	unsigned int off;	/* Offset of last byte */
@@ -875,7 +861,7 @@ static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
 	dump_stack();
 }
 
-void object_err(struct kmem_cache *s, struct page *page,
+static void object_err(struct kmem_cache *s, struct page *page,
 			u8 *object, char *reason)
 {
 	if (slab_add_kunit_errors())
@@ -886,6 +872,20 @@ void object_err(struct kmem_cache *s, struct page *page,
 	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 }
 
+static bool freelist_corrupted(struct kmem_cache *s, struct page *page,
+			       void **freelist, void *nextfree)
+{
+	if ((s->flags & SLAB_CONSISTENCY_CHECKS) &&
+	    !check_valid_pointer(s, page, nextfree) && freelist) {
+		object_err(s, page, *freelist, "Freechain corrupt");
+		*freelist = NULL;
+		slab_fix(s, "Isolate corrupted freechain");
+		return true;
+	}
+
+	return false;
+}
+
 static __printf(3, 4) void slab_err(struct kmem_cache *s, struct page *page,
 			const char *fmt, ...)
 {
-- 
2.33.1

[PATCH v2 04/33] mm: Split slab into its own type

[Vlastimil Babka]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

Make struct slab independent of struct page. It still uses the
underlying memory in struct page for storing slab-specific data,
but slab and slub can now be weaned off using struct page directly.
Some of the wrapper functions (slab_address() and slab_order())
still need to cast to struct folio, but this is a significant
disentanglement.

[ vbabka@suse.cz: Rebase on folios, use folio instead of page where possible.

  Do not duplicate flags field in struct slab, instead make the related
  accessors go through slab_folio(). For testing pfmemalloc use the
  folio_*_active flag accessors directly so the PageSlabPfmemalloc wrappers can
  be removed later.

  Make folio_slab() expect only folio_test_slab() == true folios and
  virt_to_slab() return NULL when folio_test_slab() == false.

  Move struct slab to mm/slab.h.

  Don't represent with struct slab pages that are not true slab pages, but
  just a compound page obtained directly rom page allocator (with large
  kmalloc() for SLUB and SLOB). ]

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 include/linux/mm_types.h |  10 +--
 mm/slab.h                | 167 +++++++++++++++++++++++++++++++++++++++
 mm/slub.c                |   8 +-
 3 files changed, 176 insertions(+), 9 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index c3a6e6209600..1ae3537c7920 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -56,11 +56,11 @@ struct mem_cgroup;
  * in each subpage, but you may need to restore some of their values
  * afterwards.
  *
- * SLUB uses cmpxchg_double() to atomically update its freelist and
- * counters.  That requires that freelist & counters be adjacent and
- * double-word aligned.  We align all struct pages to double-word
- * boundaries, and ensure that 'freelist' is aligned within the
- * struct.
+ * SLUB uses cmpxchg_double() to atomically update its freelist and counters.
+ * That requires that freelist & counters in struct slab be adjacent and
+ * double-word aligned. Because struct slab currently just reinterprets the
+ * bits of struct page, we align all struct pages to double-word boundaries,
+ * and ensure that 'freelist' is aligned within struct slab.
  */
 #ifdef CONFIG_HAVE_ALIGNED_STRUCT_PAGE
 #define _struct_page_alignment	__aligned(2 * sizeof(unsigned long))
diff --git a/mm/slab.h b/mm/slab.h
index 56ad7eea3ddf..0e67a8cb7f80 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -5,6 +5,173 @@
  * Internal slab definitions
  */
 
+/* Reuses the bits in struct page */
+struct slab {
+	unsigned long __page_flags;
+	union {
+		struct list_head slab_list;
+		struct {	/* Partial pages */
+			struct slab *next;
+#ifdef CONFIG_64BIT
+			int slabs;	/* Nr of slabs left */
+#else
+			short int slabs;
+#endif
+		};
+		struct rcu_head rcu_head;
+	};
+	struct kmem_cache *slab_cache; /* not slob */
+	/* Double-word boundary */
+	void *freelist;		/* first free object */
+	union {
+		void *s_mem;	/* slab: first object */
+		unsigned long counters;		/* SLUB */
+		struct {			/* SLUB */
+			unsigned inuse:16;
+			unsigned objects:15;
+			unsigned frozen:1;
+		};
+	};
+
+	union {
+		unsigned int active;		/* SLAB */
+		int units;			/* SLOB */
+	};
+	atomic_t __page_refcount;
+#ifdef CONFIG_MEMCG
+	unsigned long memcg_data;
+#endif
+};
+
+#define SLAB_MATCH(pg, sl)						\
+	static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl))
+SLAB_MATCH(flags, __page_flags);
+SLAB_MATCH(compound_head, slab_list);	/* Ensure bit 0 is clear */
+SLAB_MATCH(slab_list, slab_list);
+SLAB_MATCH(rcu_head, rcu_head);
+SLAB_MATCH(slab_cache, slab_cache);
+SLAB_MATCH(s_mem, s_mem);
+SLAB_MATCH(active, active);
+SLAB_MATCH(_refcount, __page_refcount);
+#ifdef CONFIG_MEMCG
+SLAB_MATCH(memcg_data, memcg_data);
+#endif
+#undef SLAB_MATCH
+static_assert(sizeof(struct slab) <= sizeof(struct page));
+
+/**
+ * folio_slab - Converts from folio to slab.
+ * @folio: The folio.
+ *
+ * Currently struct slab is a different representation of a folio where
+ * folio_test_slab() is true.
+ *
+ * Return: The slab which contains this folio.
+ */
+#define folio_slab(folio)	(_Generic((folio),			\
+	const struct folio *:	(const struct slab *)(folio),		\
+	struct folio *:		(struct slab *)(folio)))
+
+/**
+ * slab_folio - The folio allocated for a slab
+ * @slab: The slab.
+ *
+ * Slabs are allocated as folios that contain the individual objects and are
+ * using some fields in the first struct page of the folio - those fields are
+ * now accessed by struct slab. It is occasionally necessary to convert back to
+ * a folio in order to communicate with the rest of the mm.  Please use this
+ * helper function instead of casting yourself, as the implementation may change
+ * in the future.
+ */
+#define slab_folio(s)		(_Generic((s),				\
+	const struct slab *:	(const struct folio *)s,		\
+	struct slab *:		(struct folio *)s))
+
+/**
+ * page_slab - Converts from first struct page to slab.
+ * @p: The first (either head of compound or single) page of slab.
+ *
+ * A temporary wrapper to convert struct page to struct slab in situations where
+ * we know the page is the compound head, or single order-0 page.
+ *
+ * Long-term ideally everything would work with struct slab directly or go
+ * through folio to struct slab.
+ *
+ * Return: The slab which contains this page
+ */
+#define page_slab(p)		(_Generic((p),				\
+	const struct page *:	(const struct slab *)(p),		\
+	struct page *:		(struct slab *)(p)))
+
+/**
+ * slab_page - The first struct page allocated for a slab
+ * @slab: The slab.
+ *
+ * A convenience wrapper for converting slab to the first struct page of the
+ * underlying folio, to communicate with code not yet converted to folio or
+ * struct slab.
+ */
+#define slab_page(s) folio_page(slab_folio(s), 0)
+
+/*
+ * If network-based swap is enabled, sl*b must keep track of whether pages
+ * were allocated from pfmemalloc reserves.
+ */
+static inline bool slab_test_pfmemalloc(const struct slab *slab)
+{
+	return folio_test_active((struct folio *)slab_folio(slab));
+}
+
+static inline void slab_set_pfmemalloc(struct slab *slab)
+{
+	folio_set_active(slab_folio(slab));
+}
+
+static inline void slab_clear_pfmemalloc(struct slab *slab)
+{
+	folio_clear_active(slab_folio(slab));
+}
+
+static inline void __slab_clear_pfmemalloc(struct slab *slab)
+{
+	__folio_clear_active(slab_folio(slab));
+}
+
+static inline void *slab_address(const struct slab *slab)
+{
+	return folio_address(slab_folio(slab));
+}
+
+static inline int slab_nid(const struct slab *slab)
+{
+	return folio_nid(slab_folio(slab));
+}
+
+static inline pg_data_t *slab_pgdat(const struct slab *slab)
+{
+	return folio_pgdat(slab_folio(slab));
+}
+
+static inline struct slab *virt_to_slab(const void *addr)
+{
+	struct folio *folio = virt_to_folio(addr);
+
+	if (!folio_test_slab(folio))
+		return NULL;
+
+	return folio_slab(folio);
+}
+
+static inline int slab_order(const struct slab *slab)
+{
+	return folio_order((struct folio *)slab_folio(slab));
+}
+
+static inline size_t slab_size(const struct slab *slab)
+{
+	return PAGE_SIZE << slab_order(slab);
+}
+
 #ifdef CONFIG_SLOB
 /*
  * Common fields provided in kmem_cache by all slab allocators
diff --git a/mm/slub.c b/mm/slub.c
index 98bf50c1c145..4776bcc8c9e4 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3787,7 +3787,7 @@ static unsigned int slub_min_objects;
  * requested a higher minimum order then we start with that one instead of
  * the smallest order which will fit the object.
  */
-static inline unsigned int slab_order(unsigned int size,
+static inline unsigned int calc_slab_order(unsigned int size,
 		unsigned int min_objects, unsigned int max_order,
 		unsigned int fract_leftover)
 {
@@ -3851,7 +3851,7 @@ static inline int calculate_order(unsigned int size)
 
 		fraction = 16;
 		while (fraction >= 4) {
-			order = slab_order(size, min_objects,
+			order = calc_slab_order(size, min_objects,
 					slub_max_order, fraction);
 			if (order <= slub_max_order)
 				return order;
@@ -3864,14 +3864,14 @@ static inline int calculate_order(unsigned int size)
 	 * We were unable to place multiple objects in a slab. Now
 	 * lets see if we can place a single object there.
 	 */
-	order = slab_order(size, 1, slub_max_order, 1);
+	order = calc_slab_order(size, 1, slub_max_order, 1);
 	if (order <= slub_max_order)
 		return order;
 
 	/*
 	 * Doh this slab cannot be placed using slub_max_order.
 	 */
-	order = slab_order(size, 1, MAX_ORDER, 1);
+	order = calc_slab_order(size, 1, MAX_ORDER, 1);
 	if (order < MAX_ORDER)
 		return order;
 	return -ENOSYS;
-- 
2.33.1

Re: [PATCH v2 04/33] mm: Split slab into its own type

[Johannes Weiner]

On Wed, Dec 01, 2021 at 07:14:41PM +0100, Vlastimil Babka wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> Make struct slab independent of struct page. It still uses the
> underlying memory in struct page for storing slab-specific data,
> but slab and slub can now be weaned off using struct page directly.
> Some of the wrapper functions (slab_address() and slab_order())
> still need to cast to struct folio, but this is a significant
> disentanglement.
> 
> [ vbabka@suse.cz: Rebase on folios, use folio instead of page where possible.
> 
>   Do not duplicate flags field in struct slab, instead make the related
>   accessors go through slab_folio(). For testing pfmemalloc use the
>   folio_*_active flag accessors directly so the PageSlabPfmemalloc wrappers can
>   be removed later.
> 
>   Make folio_slab() expect only folio_test_slab() == true folios and
>   virt_to_slab() return NULL when folio_test_slab() == false.
> 
>   Move struct slab to mm/slab.h.
> 
>   Don't represent with struct slab pages that are not true slab pages, but
>   just a compound page obtained directly rom page allocator (with large
>   kmalloc() for SLUB and SLOB). ]
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

[PATCH v2 05/33] mm: Add account_slab() and unaccount_slab()

[Vlastimil Babka]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

These functions take struct slab instead of struct page and replace
(un)account_slab_page(). For now their callers just convert page to slab.

[ vbabka@suse.cz: replace existing functions instead of calling them ]

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slab.c |  4 ++--
 mm/slab.h | 17 ++++++++---------
 mm/slub.c |  4 ++--
 3 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index 381875e23277..7f147805d0ab 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1380,7 +1380,7 @@ static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
 		return NULL;
 	}
 
-	account_slab_page(page, cachep->gfporder, cachep, flags);
+	account_slab(page_slab(page), cachep->gfporder, cachep, flags);
 	__SetPageSlab(page);
 	/* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
 	if (sk_memalloc_socks() && page_is_pfmemalloc(page))
@@ -1405,7 +1405,7 @@ static void kmem_freepages(struct kmem_cache *cachep, struct page *page)
 
 	if (current->reclaim_state)
 		current->reclaim_state->reclaimed_slab += 1 << order;
-	unaccount_slab_page(page, order, cachep);
+	unaccount_slab(page_slab(page), order, cachep);
 	__free_pages(page, order);
 }
 
diff --git a/mm/slab.h b/mm/slab.h
index 0e67a8cb7f80..dd3f72fddff6 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -583,24 +583,23 @@ static inline struct kmem_cache *virt_to_cache(const void *obj)
 	return page->slab_cache;
 }
 
-static __always_inline void account_slab_page(struct page *page, int order,
-					      struct kmem_cache *s,
-					      gfp_t gfp)
+static __always_inline void account_slab(struct slab *slab, int order,
+					 struct kmem_cache *s, gfp_t gfp)
 {
 	if (memcg_kmem_enabled() && (s->flags & SLAB_ACCOUNT))
-		memcg_alloc_page_obj_cgroups(page, s, gfp, true);
+		memcg_alloc_page_obj_cgroups(slab_page(slab), s, gfp, true);
 
-	mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
+	mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
 			    PAGE_SIZE << order);
 }
 
-static __always_inline void unaccount_slab_page(struct page *page, int order,
-						struct kmem_cache *s)
+static __always_inline void unaccount_slab(struct slab *slab, int order,
+					   struct kmem_cache *s)
 {
 	if (memcg_kmem_enabled())
-		memcg_free_page_obj_cgroups(page);
+		memcg_free_page_obj_cgroups(slab_page(slab));
 
-	mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
+	mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
 			    -(PAGE_SIZE << order));
 }
 
diff --git a/mm/slub.c b/mm/slub.c
index 4776bcc8c9e4..8b172de26c67 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1943,7 +1943,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 
 	page->objects = oo_objects(oo);
 
-	account_slab_page(page, oo_order(oo), s, flags);
+	account_slab(page_slab(page), oo_order(oo), s, flags);
 
 	page->slab_cache = s;
 	__SetPageSlab(page);
@@ -2014,7 +2014,7 @@ static void __free_slab(struct kmem_cache *s, struct page *page)
 	page->slab_cache = NULL;
 	if (current->reclaim_state)
 		current->reclaim_state->reclaimed_slab += pages;
-	unaccount_slab_page(page, order, s);
+	unaccount_slab(page_slab(page), order, s);
 	__free_pages(page, order);
 }
 
-- 
2.33.1

Re: [PATCH v2 05/33] mm: Add account_slab() and unaccount_slab()

[Johannes Weiner]

On Wed, Dec 01, 2021 at 07:14:42PM +0100, Vlastimil Babka wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> These functions take struct slab instead of struct page and replace
> (un)account_slab_page(). For now their callers just convert page to slab.
> 
> [ vbabka@suse.cz: replace existing functions instead of calling them ]
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

[PATCH v2 06/33] mm: Convert virt_to_cache() to use struct slab

[Vlastimil Babka]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

This function is entirely self-contained, so can be converted from
page to slab.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slab.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/slab.h b/mm/slab.h
index dd3f72fddff6..1408ada9ff72 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -574,13 +574,13 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s,
 
 static inline struct kmem_cache *virt_to_cache(const void *obj)
 {
-	struct page *page;
+	struct slab *slab;
 
-	page = virt_to_head_page(obj);
-	if (WARN_ONCE(!PageSlab(page), "%s: Object is not a Slab page!\n",
+	slab = virt_to_slab(obj);
+	if (WARN_ONCE(!slab, "%s: Object is not a Slab page!\n",
 					__func__))
 		return NULL;
-	return page->slab_cache;
+	return slab->slab_cache;
 }
 
 static __always_inline void account_slab(struct slab *slab, int order,
-- 
2.33.1

Re: [PATCH v2 06/33] mm: Convert virt_to_cache() to use struct slab

[Johannes Weiner]

On Wed, Dec 01, 2021 at 07:14:43PM +0100, Vlastimil Babka wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> This function is entirely self-contained, so can be converted from
> page to slab.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

[PATCH v2 07/33] mm: Convert __ksize() to struct slab

[Vlastimil Babka]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

In SLUB, use folios, and struct slab to access slab_cache field.
In SLOB, use folios to properly resolve pointers beyond
PAGE_SIZE offset of the object.

[ vbabka@suse.cz: use folios, and only convert folio_test_slab() == true folios
  to struct slab ]

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slob.c |  8 ++++----
 mm/slub.c | 12 +++++-------
 2 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/mm/slob.c b/mm/slob.c
index 03deee1e6a94..c8a4290012a6 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -570,7 +570,7 @@ EXPORT_SYMBOL(kfree);
 /* can't use ksize for kmem_cache_alloc memory, only kmalloc */
 size_t __ksize(const void *block)
 {
-	struct page *sp;
+	struct folio *folio;
 	int align;
 	unsigned int *m;
 
@@ -578,9 +578,9 @@ size_t __ksize(const void *block)
 	if (unlikely(block == ZERO_SIZE_PTR))
 		return 0;
 
-	sp = virt_to_page(block);
-	if (unlikely(!PageSlab(sp)))
-		return page_size(sp);
+	folio = virt_to_folio(block);
+	if (unlikely(!folio_test_slab(folio)))
+		return folio_size(folio);
 
 	align = max_t(size_t, ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
 	m = (unsigned int *)(block - align);
diff --git a/mm/slub.c b/mm/slub.c
index 8b172de26c67..6ae7c63cedc0 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4527,19 +4527,17 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
 
 size_t __ksize(const void *object)
 {
-	struct page *page;
+	struct folio *folio;
 
 	if (unlikely(object == ZERO_SIZE_PTR))
 		return 0;
 
-	page = virt_to_head_page(object);
+	folio = virt_to_folio(object);
 
-	if (unlikely(!PageSlab(page))) {
-		WARN_ON(!PageCompound(page));
-		return page_size(page);
-	}
+	if (unlikely(!folio_test_slab(folio)))
+		return folio_size(folio);
 
-	return slab_ksize(page->slab_cache);
+	return slab_ksize(folio_slab(folio)->slab_cache);
 }
 EXPORT_SYMBOL(__ksize);
 
-- 
2.33.1

Re: [PATCH v2 07/33] mm: Convert __ksize() to struct slab

[Johannes Weiner]

On Wed, Dec 01, 2021 at 07:14:44PM +0100, Vlastimil Babka wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> In SLUB, use folios, and struct slab to access slab_cache field.
> In SLOB, use folios to properly resolve pointers beyond
> PAGE_SIZE offset of the object.
> 
> [ vbabka@suse.cz: use folios, and only convert folio_test_slab() == true folios
>   to struct slab ]
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

Awesome.

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

[PATCH v2 08/33] mm: Use struct slab in kmem_obj_info()

[Vlastimil Babka]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

All three implementations of slab support kmem_obj_info() which reports
details of an object allocated from the slab allocator.  By using the
slab type instead of the page type, we make it obvious that this can
only be called for slabs.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slab.c        | 12 ++++++------
 mm/slab.h        |  4 ++--
 mm/slab_common.c |  8 ++++----
 mm/slob.c        |  4 ++--
 mm/slub.c        | 12 ++++++------
 5 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index 7f147805d0ab..44bc1fcd1393 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3646,21 +3646,21 @@ EXPORT_SYMBOL(__kmalloc_node_track_caller);
 #endif /* CONFIG_NUMA */
 
 #ifdef CONFIG_PRINTK
-void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
+void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
 {
 	struct kmem_cache *cachep;
 	unsigned int objnr;
 	void *objp;
 
 	kpp->kp_ptr = object;
-	kpp->kp_page = page;
-	cachep = page->slab_cache;
+	kpp->kp_slab = slab;
+	cachep = slab->slab_cache;
 	kpp->kp_slab_cache = cachep;
 	objp = object - obj_offset(cachep);
 	kpp->kp_data_offset = obj_offset(cachep);
-	page = virt_to_head_page(objp);
-	objnr = obj_to_index(cachep, page, objp);
-	objp = index_to_obj(cachep, page, objnr);
+	slab = virt_to_slab(objp);
+	objnr = obj_to_index(cachep, slab_page(slab), objp);
+	objp = index_to_obj(cachep, slab_page(slab), objnr);
 	kpp->kp_objp = objp;
 	if (DEBUG && cachep->flags & SLAB_STORE_USER)
 		kpp->kp_ret = *dbg_userword(cachep, objp);
diff --git a/mm/slab.h b/mm/slab.h
index 1408ada9ff72..9ae9f6c3d1cb 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -801,7 +801,7 @@ static inline void debugfs_slab_release(struct kmem_cache *s) { }
 #define KS_ADDRS_COUNT 16
 struct kmem_obj_info {
 	void *kp_ptr;
-	struct page *kp_page;
+	struct slab *kp_slab;
 	void *kp_objp;
 	unsigned long kp_data_offset;
 	struct kmem_cache *kp_slab_cache;
@@ -809,7 +809,7 @@ struct kmem_obj_info {
 	void *kp_stack[KS_ADDRS_COUNT];
 	void *kp_free_stack[KS_ADDRS_COUNT];
 };
-void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page);
+void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab);
 #endif
 
 #endif /* MM_SLAB_H */
diff --git a/mm/slab_common.c b/mm/slab_common.c
index e5d080a93009..bddefca7d584 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -579,18 +579,18 @@ void kmem_dump_obj(void *object)
 {
 	char *cp = IS_ENABLED(CONFIG_MMU) ? "" : "/vmalloc";
 	int i;
-	struct page *page;
+	struct slab *slab;
 	unsigned long ptroffset;
 	struct kmem_obj_info kp = { };
 
 	if (WARN_ON_ONCE(!virt_addr_valid(object)))
 		return;
-	page = virt_to_head_page(object);
-	if (WARN_ON_ONCE(!PageSlab(page))) {
+	slab = virt_to_slab(object);
+	if (WARN_ON_ONCE(!slab)) {
 		pr_cont(" non-slab memory.\n");
 		return;
 	}
-	kmem_obj_info(&kp, object, page);
+	kmem_obj_info(&kp, object, slab);
 	if (kp.kp_slab_cache)
 		pr_cont(" slab%s %s", cp, kp.kp_slab_cache->name);
 	else
diff --git a/mm/slob.c b/mm/slob.c
index c8a4290012a6..d2d15e7f191c 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -462,10 +462,10 @@ static void slob_free(void *block, int size)
 }
 
 #ifdef CONFIG_PRINTK
-void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
+void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
 {
 	kpp->kp_ptr = object;
-	kpp->kp_page = page;
+	kpp->kp_slab = slab;
 }
 #endif
 
diff --git a/mm/slub.c b/mm/slub.c
index 6ae7c63cedc0..bc8a1fa146a5 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4322,31 +4322,31 @@ int __kmem_cache_shutdown(struct kmem_cache *s)
 }
 
 #ifdef CONFIG_PRINTK
-void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
+void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
 {
 	void *base;
 	int __maybe_unused i;
 	unsigned int objnr;
 	void *objp;
 	void *objp0;
-	struct kmem_cache *s = page->slab_cache;
+	struct kmem_cache *s = slab->slab_cache;
 	struct track __maybe_unused *trackp;
 
 	kpp->kp_ptr = object;
-	kpp->kp_page = page;
+	kpp->kp_slab = slab;
 	kpp->kp_slab_cache = s;
-	base = page_address(page);
+	base = slab_address(slab);
 	objp0 = kasan_reset_tag(object);
 #ifdef CONFIG_SLUB_DEBUG
 	objp = restore_red_left(s, objp0);
 #else
 	objp = objp0;
 #endif
-	objnr = obj_to_index(s, page, objp);
+	objnr = obj_to_index(s, slab_page(slab), objp);
 	kpp->kp_data_offset = (unsigned long)((char *)objp0 - (char *)objp);
 	objp = base + s->size * objnr;
 	kpp->kp_objp = objp;
-	if (WARN_ON_ONCE(objp < base || objp >= base + page->objects * s->size || (objp - base) % s->size) ||
+	if (WARN_ON_ONCE(objp < base || objp >= base + slab->objects * s->size || (objp - base) % s->size) ||
 	    !(s->flags & SLAB_STORE_USER))
 		return;
 #ifdef CONFIG_SLUB_DEBUG
-- 
2.33.1

[PATCH v2 09/33] mm: Convert check_heap_object() to use struct slab

[Vlastimil Babka]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

Ensure that we're not seeing a tail page inside __check_heap_object()
by converting to a slab instead of a page.  Take the opportunity to
mark the slab as const since we're not modifying it.  Also move the
declaration of __check_heap_object() to mm/slab.h so it's not
available to the wider kernel.

[ vbabka@suse.cz: in check_heap_object() only convert to struct slab for
  actual PageSlab pages; use folio as intermediate step instead of page ]

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 include/linux/slab.h |  8 --------
 mm/slab.c            | 14 +++++++-------
 mm/slab.h            |  9 +++++++++
 mm/slub.c            | 10 +++++-----
 mm/usercopy.c        | 13 +++++++------
 5 files changed, 28 insertions(+), 26 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 181045148b06..367366f1d1ff 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -189,14 +189,6 @@ bool kmem_valid_obj(void *object);
 void kmem_dump_obj(void *object);
 #endif
 
-#ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
-void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
-			bool to_user);
-#else
-static inline void __check_heap_object(const void *ptr, unsigned long n,
-				       struct page *page, bool to_user) { }
-#endif
-
 /*
  * Some archs want to perform DMA into kmalloc caches and need a guaranteed
  * alignment larger than the alignment of a 64-bit integer.
diff --git a/mm/slab.c b/mm/slab.c
index 44bc1fcd1393..38fcd3f496df 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -372,8 +372,8 @@ static void **dbg_userword(struct kmem_cache *cachep, void *objp)
 static int slab_max_order = SLAB_MAX_ORDER_LO;
 static bool slab_max_order_set __initdata;
 
-static inline void *index_to_obj(struct kmem_cache *cache, struct page *page,
-				 unsigned int idx)
+static inline void *index_to_obj(struct kmem_cache *cache,
+				 const struct page *page, unsigned int idx)
 {
 	return page->s_mem + cache->size * idx;
 }
@@ -4166,8 +4166,8 @@ ssize_t slabinfo_write(struct file *file, const char __user *buffer,
  * Returns NULL if check passes, otherwise const char * to name of cache
  * to indicate an error.
  */
-void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
-			 bool to_user)
+void __check_heap_object(const void *ptr, unsigned long n,
+			 const struct slab *slab, bool to_user)
 {
 	struct kmem_cache *cachep;
 	unsigned int objnr;
@@ -4176,15 +4176,15 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
 	ptr = kasan_reset_tag(ptr);
 
 	/* Find and validate object. */
-	cachep = page->slab_cache;
-	objnr = obj_to_index(cachep, page, (void *)ptr);
+	cachep = slab->slab_cache;
+	objnr = obj_to_index(cachep, slab_page(slab), (void *)ptr);
 	BUG_ON(objnr >= cachep->num);
 
 	/* Find offset within object. */
 	if (is_kfence_address(ptr))
 		offset = ptr - kfence_object_start(ptr);
 	else
-		offset = ptr - index_to_obj(cachep, page, objnr) - obj_offset(cachep);
+		offset = ptr - index_to_obj(cachep, slab_page(slab), objnr) - obj_offset(cachep);
 
 	/* Allow address range falling entirely within usercopy region. */
 	if (offset >= cachep->useroffset &&
diff --git a/mm/slab.h b/mm/slab.h
index 9ae9f6c3d1cb..7376c9d8aa2b 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -812,4 +812,13 @@ struct kmem_obj_info {
 void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab);
 #endif
 
+#ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
+void __check_heap_object(const void *ptr, unsigned long n,
+			 const struct slab *slab, bool to_user);
+#else
+static inline
+void __check_heap_object(const void *ptr, unsigned long n,
+			 const struct slab *slab, bool to_user) { }
+#endif
+
 #endif /* MM_SLAB_H */
diff --git a/mm/slub.c b/mm/slub.c
index bc8a1fa146a5..0d31274743d9 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4484,8 +4484,8 @@ EXPORT_SYMBOL(__kmalloc_node);
  * Returns NULL if check passes, otherwise const char * to name of cache
  * to indicate an error.
  */
-void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
-			 bool to_user)
+void __check_heap_object(const void *ptr, unsigned long n,
+			 const struct slab *slab, bool to_user)
 {
 	struct kmem_cache *s;
 	unsigned int offset;
@@ -4494,10 +4494,10 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
 	ptr = kasan_reset_tag(ptr);
 
 	/* Find object and usable object size. */
-	s = page->slab_cache;
+	s = slab->slab_cache;
 
 	/* Reject impossible pointers. */
-	if (ptr < page_address(page))
+	if (ptr < slab_address(slab))
 		usercopy_abort("SLUB object not in SLUB page?!", NULL,
 			       to_user, 0, n);
 
@@ -4505,7 +4505,7 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
 	if (is_kfence)
 		offset = ptr - kfence_object_start(ptr);
 	else
-		offset = (ptr - page_address(page)) % s->size;
+		offset = (ptr - slab_address(slab)) % s->size;
 
 	/* Adjust for redzone and reject if within the redzone. */
 	if (!is_kfence && kmem_cache_debug_flags(s, SLAB_RED_ZONE)) {
diff --git a/mm/usercopy.c b/mm/usercopy.c
index b3de3c4eefba..d0d268135d96 100644
--- a/mm/usercopy.c
+++ b/mm/usercopy.c
@@ -20,6 +20,7 @@
 #include <linux/atomic.h>
 #include <linux/jump_label.h>
 #include <asm/sections.h>
+#include "slab.h"
 
 /*
  * Checks if a given pointer and length is contained by the current
@@ -223,7 +224,7 @@ static inline void check_page_span(const void *ptr, unsigned long n,
 static inline void check_heap_object(const void *ptr, unsigned long n,
 				     bool to_user)
 {
-	struct page *page;
+	struct folio *folio;
 
 	if (!virt_addr_valid(ptr))
 		return;
@@ -231,16 +232,16 @@ static inline void check_heap_object(const void *ptr, unsigned long n,
 	/*
 	 * When CONFIG_HIGHMEM=y, kmap_to_page() will give either the
 	 * highmem page or fallback to virt_to_page(). The following
-	 * is effectively a highmem-aware virt_to_head_page().
+	 * is effectively a highmem-aware virt_to_slab().
 	 */
-	page = compound_head(kmap_to_page((void *)ptr));
+	folio = page_folio(kmap_to_page((void *)ptr));
 
-	if (PageSlab(page)) {
+	if (folio_test_slab(folio)) {
 		/* Check slab allocator for flags and size. */
-		__check_heap_object(ptr, n, page, to_user);
+		__check_heap_object(ptr, n, folio_slab(folio), to_user);
 	} else {
 		/* Verify object does not incorrectly span multiple pages. */
-		check_page_span(ptr, n, page, to_user);
+		check_page_span(ptr, n, folio_page(folio, 0), to_user);
 	}
 }
 
-- 
2.33.1

[PATCH v2 10/33] mm/slub: Convert detached_freelist to use a struct slab

[Vlastimil Babka]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

This gives us a little bit of extra typesafety as we know that
nobody called virt_to_page() instead of virt_to_head_page().

[ vbabka@suse.cz: Use folio as intermediate step when filtering out
  large kmalloc pages ]

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slub.c | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 0d31274743d9..9bdb0a5d6ab2 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3532,7 +3532,7 @@ void kmem_cache_free(struct kmem_cache *s, void *x)
 EXPORT_SYMBOL(kmem_cache_free);
 
 struct detached_freelist {
-	struct page *page;
+	struct slab *slab;
 	void *tail;
 	void *freelist;
 	int cnt;
@@ -3554,8 +3554,8 @@ static inline void free_nonslab_page(struct page *page, void *object)
 /*
  * This function progressively scans the array with free objects (with
  * a limited look ahead) and extract objects belonging to the same
- * page.  It builds a detached freelist directly within the given
- * page/objects.  This can happen without any need for
+ * slab.  It builds a detached freelist directly within the given
+ * slab/objects.  This can happen without any need for
  * synchronization, because the objects are owned by running process.
  * The freelist is build up as a single linked list in the objects.
  * The idea is, that this detached freelist can then be bulk
@@ -3570,10 +3570,11 @@ int build_detached_freelist(struct kmem_cache *s, size_t size,
 	size_t first_skipped_index = 0;
 	int lookahead = 3;
 	void *object;
-	struct page *page;
+	struct folio *folio;
+	struct slab *slab;
 
 	/* Always re-init detached_freelist */
-	df->page = NULL;
+	df->slab = NULL;
 
 	do {
 		object = p[--size];
@@ -3583,17 +3584,19 @@ int build_detached_freelist(struct kmem_cache *s, size_t size,
 	if (!object)
 		return 0;
 
-	page = virt_to_head_page(object);
+	folio = virt_to_folio(object);
 	if (!s) {
 		/* Handle kalloc'ed objects */
-		if (unlikely(!PageSlab(page))) {
-			free_nonslab_page(page, object);
+		if (unlikely(!folio_test_slab(folio))) {
+			free_nonslab_page(folio_page(folio, 0), object);
 			p[size] = NULL; /* mark object processed */
 			return size;
 		}
 		/* Derive kmem_cache from object */
-		df->s = page->slab_cache;
+		slab = folio_slab(folio);
+		df->s = slab->slab_cache;
 	} else {
+		slab = folio_slab(folio);
 		df->s = cache_from_obj(s, object); /* Support for memcg */
 	}
 
@@ -3605,7 +3608,7 @@ int build_detached_freelist(struct kmem_cache *s, size_t size,
 	}
 
 	/* Start new detached freelist */
-	df->page = page;
+	df->slab = slab;
 	set_freepointer(df->s, object, NULL);
 	df->tail = object;
 	df->freelist = object;
@@ -3617,8 +3620,8 @@ int build_detached_freelist(struct kmem_cache *s, size_t size,
 		if (!object)
 			continue; /* Skip processed objects */
 
-		/* df->page is always set at this point */
-		if (df->page == virt_to_head_page(object)) {
+		/* df->slab is always set at this point */
+		if (df->slab == virt_to_slab(object)) {
 			/* Opportunity build freelist */
 			set_freepointer(df->s, object, df->freelist);
 			df->freelist = object;
@@ -3650,10 +3653,10 @@ void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
 		struct detached_freelist df;
 
 		size = build_detached_freelist(s, size, p, &df);
-		if (!df.page)
+		if (!df.slab)
 			continue;
 
-		slab_free(df.s, df.page, df.freelist, df.tail, df.cnt, _RET_IP_);
+		slab_free(df.s, slab_page(df.slab), df.freelist, df.tail, df.cnt, _RET_IP_);
 	} while (likely(size));
 }
 EXPORT_SYMBOL(kmem_cache_free_bulk);
-- 
2.33.1

[PATCH v2 11/33] mm/slub: Convert kfree() to use a struct slab

[Vlastimil Babka]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

Convert kfree(), kmem_cache_free() and ___cache_free() to resolve object
addresses to struct slab, using folio as intermediate step where needed. Keep
passing the result as struct page for now in preparation for mass conversion of
internal functions.

[ vbabka@suse.cz: Use folio as intermediate step when checking for
  large kmalloc pages ]

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slub.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 9bdb0a5d6ab2..2d9c1b3c9f37 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3517,7 +3517,7 @@ static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
 #ifdef CONFIG_KASAN_GENERIC
 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
 {
-	do_slab_free(cache, virt_to_head_page(x), x, NULL, 1, addr);
+	do_slab_free(cache, slab_page(virt_to_slab(x)), x, NULL, 1, addr);
 }
 #endif
 
@@ -3527,7 +3527,7 @@ void kmem_cache_free(struct kmem_cache *s, void *x)
 	if (!s)
 		return;
 	trace_kmem_cache_free(_RET_IP_, x, s->name);
-	slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_);
+	slab_free(s, slab_page(virt_to_slab(x)), x, NULL, 1, _RET_IP_);
 }
 EXPORT_SYMBOL(kmem_cache_free);
 
@@ -4546,7 +4546,8 @@ EXPORT_SYMBOL(__ksize);
 
 void kfree(const void *x)
 {
-	struct page *page;
+	struct folio *folio;
+	struct slab *slab;
 	void *object = (void *)x;
 
 	trace_kfree(_RET_IP_, x);
@@ -4554,12 +4555,13 @@ void kfree(const void *x)
 	if (unlikely(ZERO_OR_NULL_PTR(x)))
 		return;
 
-	page = virt_to_head_page(x);
-	if (unlikely(!PageSlab(page))) {
-		free_nonslab_page(page, object);
+	folio = virt_to_folio(x);
+	if (unlikely(!folio_test_slab(folio))) {
+		free_nonslab_page(folio_page(folio, 0), object);
 		return;
 	}
-	slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_);
+	slab = folio_slab(folio);
+	slab_free(slab->slab_cache, slab_page(slab), object, NULL, 1, _RET_IP_);
 }
 EXPORT_SYMBOL(kfree);
 
-- 
2.33.1

[PATCH v2 12/33] mm/slub: Convert __slab_lock() and __slab_unlock() to struct slab

[Vlastimil Babka]

These functions operate on the PG_locked page flag, but make them accept
struct slab to encapsulate this implementation detail.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slub.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 2d9c1b3c9f37..2cbd2403005f 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -440,14 +440,18 @@ slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
 /*
  * Per slab locking using the pagelock
  */
-static __always_inline void __slab_lock(struct page *page)
+static __always_inline void __slab_lock(struct slab *slab)
 {
+	struct page *page = slab_page(slab);
+
 	VM_BUG_ON_PAGE(PageTail(page), page);
 	bit_spin_lock(PG_locked, &page->flags);
 }
 
-static __always_inline void __slab_unlock(struct page *page)
+static __always_inline void __slab_unlock(struct slab *slab)
 {
+	struct page *page = slab_page(slab);
+
 	VM_BUG_ON_PAGE(PageTail(page), page);
 	__bit_spin_unlock(PG_locked, &page->flags);
 }
@@ -456,12 +460,12 @@ static __always_inline void slab_lock(struct page *page, unsigned long *flags)
 {
 	if (IS_ENABLED(CONFIG_PREEMPT_RT))
 		local_irq_save(*flags);
-	__slab_lock(page);
+	__slab_lock(page_slab(page));
 }
 
 static __always_inline void slab_unlock(struct page *page, unsigned long *flags)
 {
-	__slab_unlock(page);
+	__slab_unlock(page_slab(page));
 	if (IS_ENABLED(CONFIG_PREEMPT_RT))
 		local_irq_restore(*flags);
 }
@@ -530,16 +534,16 @@ static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
 		unsigned long flags;
 
 		local_irq_save(flags);
-		__slab_lock(page);
+		__slab_lock(page_slab(page));
 		if (page->freelist == freelist_old &&
 					page->counters == counters_old) {
 			page->freelist = freelist_new;
 			page->counters = counters_new;
-			__slab_unlock(page);
+			__slab_unlock(page_slab(page));
 			local_irq_restore(flags);
 			return true;
 		}
-		__slab_unlock(page);
+		__slab_unlock(page_slab(page));
 		local_irq_restore(flags);
 	}
 
-- 
2.33.1

[PATCH v2 13/33] mm/slub: Convert print_page_info() to print_slab_info()

[Vlastimil Babka]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

Improve the type safety and prepare for further conversion. For flags
access, convert to folio internally.

[ vbabka@suse.cz: access flags via folio_flags() ]

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slub.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 2cbd2403005f..a4f7dafe0610 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -788,12 +788,13 @@ void print_tracking(struct kmem_cache *s, void *object)
 	print_track("Freed", get_track(s, object, TRACK_FREE), pr_time);
 }
 
-static void print_page_info(struct page *page)
+static void print_slab_info(const struct slab *slab)
 {
-	pr_err("Slab 0x%p objects=%u used=%u fp=0x%p flags=%pGp\n",
-	       page, page->objects, page->inuse, page->freelist,
-	       &page->flags);
+	struct folio *folio = (struct folio *)slab_folio(slab);
 
+	pr_err("Slab 0x%p objects=%u used=%u fp=0x%p flags=%pGp\n",
+	       slab, slab->objects, slab->inuse, slab->freelist,
+	       folio_flags(folio, 0));
 }
 
 static void slab_bug(struct kmem_cache *s, char *fmt, ...)
@@ -833,7 +834,7 @@ static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
 
 	print_tracking(s, p);
 
-	print_page_info(page);
+	print_slab_info(page_slab(page));
 
 	pr_err("Object 0x%p @offset=%tu fp=0x%p\n\n",
 	       p, p - addr, get_freepointer(s, p));
@@ -903,7 +904,7 @@ static __printf(3, 4) void slab_err(struct kmem_cache *s, struct page *page,
 	vsnprintf(buf, sizeof(buf), fmt, args);
 	va_end(args);
 	slab_bug(s, "%s", buf);
-	print_page_info(page);
+	print_slab_info(page_slab(page));
 	dump_stack();
 	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 }
-- 
2.33.1

[PATCH v2 14/33] mm/slub: Convert alloc_slab_page() to return a struct slab

[Vlastimil Babka]

Preparatory, callers convert back to struct page for now.

Also move setting page flags to alloc_slab_page() where we still operate on a
struct page. This means the page->slab_cache pointer is now set later than the
PageSlab flag, which could theoretically confuse some pfn walker assuming
PageSlab means there would be a valid cache pointer. But as the code had no
barriers and used __set_bit() anyway, it could have happened already, so there
shouldn't be such a walker.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slub.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index a4f7dafe0610..3d82e8e0fc2b 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1788,18 +1788,27 @@ static void *setup_object(struct kmem_cache *s, struct page *page,
 /*
  * Slab allocation and freeing
  */
-static inline struct page *alloc_slab_page(struct kmem_cache *s,
+static inline struct slab *alloc_slab_page(struct kmem_cache *s,
 		gfp_t flags, int node, struct kmem_cache_order_objects oo)
 {
-	struct page *page;
+	struct folio *folio;
+	struct slab *slab;
 	unsigned int order = oo_order(oo);
 
 	if (node == NUMA_NO_NODE)
-		page = alloc_pages(flags, order);
+		folio = (struct folio *)alloc_pages(flags, order);
 	else
-		page = __alloc_pages_node(node, flags, order);
+		folio = (struct folio *)__alloc_pages_node(node, flags, order);
 
-	return page;
+	if (!folio)
+		return NULL;
+
+	slab = folio_slab(folio);
+	__folio_set_slab(folio);
+	if (page_is_pfmemalloc(folio_page(folio, 0)))
+		slab_set_pfmemalloc(slab);
+
+	return slab;
 }
 
 #ifdef CONFIG_SLAB_FREELIST_RANDOM
@@ -1932,7 +1941,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 	if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
 		alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
 
-	page = alloc_slab_page(s, alloc_gfp, node, oo);
+	page = slab_page(alloc_slab_page(s, alloc_gfp, node, oo));
 	if (unlikely(!page)) {
 		oo = s->min;
 		alloc_gfp = flags;
@@ -1940,7 +1949,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 		 * Allocation may have failed due to fragmentation.
 		 * Try a lower order alloc if possible
 		 */
-		page = alloc_slab_page(s, alloc_gfp, node, oo);
+		page = slab_page(alloc_slab_page(s, alloc_gfp, node, oo));
 		if (unlikely(!page))
 			goto out;
 		stat(s, ORDER_FALLBACK);
@@ -1951,9 +1960,6 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 	account_slab(page_slab(page), oo_order(oo), s, flags);
 
 	page->slab_cache = s;
-	__SetPageSlab(page);
-	if (page_is_pfmemalloc(page))
-		SetPageSlabPfmemalloc(page);
 
 	kasan_poison_slab(page);
 
-- 
2.33.1

[PATCH v2 15/33] mm/slub: Convert __free_slab() to use struct slab

[Vlastimil Babka]

__free_slab() is on the boundary of distinguishing struct slab and struct page
so start with struct slab but convert to folio for working with flags and
folio_page() to call functions that require struct page.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slub.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 3d82e8e0fc2b..daa5c5b605d6 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2005,35 +2005,35 @@ static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
 		flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
 }
 
-static void __free_slab(struct kmem_cache *s, struct page *page)
+static void __free_slab(struct kmem_cache *s, struct slab *slab)
 {
-	int order = compound_order(page);
+	struct folio *folio = slab_folio(slab);
+	int order = folio_order(folio);
 	int pages = 1 << order;
 
 	if (kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS)) {
 		void *p;
 
-		slab_pad_check(s, page);
-		for_each_object(p, s, page_address(page),
-						page->objects)
-			check_object(s, page, p, SLUB_RED_INACTIVE);
+		slab_pad_check(s, folio_page(folio, 0));
+		for_each_object(p, s, slab_address(slab), slab->objects)
+			check_object(s, folio_page(folio, 0), p, SLUB_RED_INACTIVE);
 	}
 
-	__ClearPageSlabPfmemalloc(page);
-	__ClearPageSlab(page);
+	__slab_clear_pfmemalloc(slab);
+	__folio_clear_slab(folio);
 	/* In union with page->mapping where page allocator expects NULL */
-	page->slab_cache = NULL;
+	slab->slab_cache = NULL;
 	if (current->reclaim_state)
 		current->reclaim_state->reclaimed_slab += pages;
-	unaccount_slab(page_slab(page), order, s);
-	__free_pages(page, order);
+	unaccount_slab(slab, order, s);
+	__free_pages(folio_page(folio, 0), order);
 }
 
 static void rcu_free_slab(struct rcu_head *h)
 {
 	struct page *page = container_of(h, struct page, rcu_head);
 
-	__free_slab(page->slab_cache, page);
+	__free_slab(page->slab_cache, page_slab(page));
 }
 
 static void free_slab(struct kmem_cache *s, struct page *page)
@@ -2041,7 +2041,7 @@ static void free_slab(struct kmem_cache *s, struct page *page)
 	if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) {
 		call_rcu(&page->rcu_head, rcu_free_slab);
 	} else
-		__free_slab(s, page);
+		__free_slab(s, page_slab(page));
 }
 
 static void discard_slab(struct kmem_cache *s, struct page *page)
-- 
2.33.1

[PATCH v2 16/33] mm/slub: Convert pfmemalloc_match() to take a struct slab

[Vlastimil Babka]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

Preparatory for mass conversion. Use the new slab_test_pfmemalloc() helper.  As
it doesn't do VM_BUG_ON(!PageSlab()) we no longer need the
pfmemalloc_match_unsafe() variant.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slub.c | 25 ++++++-------------------
 1 file changed, 6 insertions(+), 19 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index daa5c5b605d6..8224962c81aa 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2129,7 +2129,7 @@ static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
 static inline void put_cpu_partial(struct kmem_cache *s, struct page *page,
 				   int drain) { }
 #endif
-static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags);
+static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags);
 
 /*
  * Try to allocate a partial slab from a specific node.
@@ -2155,7 +2155,7 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
 	list_for_each_entry_safe(page, page2, &n->partial, slab_list) {
 		void *t;
 
-		if (!pfmemalloc_match(page, gfpflags))
+		if (!pfmemalloc_match(page_slab(page), gfpflags))
 			continue;
 
 		t = acquire_slab(s, n, page, object == NULL);
@@ -2833,22 +2833,9 @@ slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
 #endif
 }
 
-static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags)
+static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags)
 {
-	if (unlikely(PageSlabPfmemalloc(page)))
-		return gfp_pfmemalloc_allowed(gfpflags);
-
-	return true;
-}
-
-/*
- * A variant of pfmemalloc_match() that tests page flags without asserting
- * PageSlab. Intended for opportunistic checks before taking a lock and
- * rechecking that nobody else freed the page under us.
- */
-static inline bool pfmemalloc_match_unsafe(struct page *page, gfp_t gfpflags)
-{
-	if (unlikely(__PageSlabPfmemalloc(page)))
+	if (unlikely(slab_test_pfmemalloc(slab)))
 		return gfp_pfmemalloc_allowed(gfpflags);
 
 	return true;
@@ -2950,7 +2937,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 	 * PFMEMALLOC but right now, we are losing the pfmemalloc
 	 * information when the page leaves the per-cpu allocator
 	 */
-	if (unlikely(!pfmemalloc_match_unsafe(page, gfpflags)))
+	if (unlikely(!pfmemalloc_match(page_slab(page), gfpflags)))
 		goto deactivate_slab;
 
 	/* must check again c->page in case we got preempted and it changed */
@@ -3062,7 +3049,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 		}
 	}
 
-	if (unlikely(!pfmemalloc_match(page, gfpflags)))
+	if (unlikely(!pfmemalloc_match(page_slab(page), gfpflags)))
 		/*
 		 * For !pfmemalloc_match() case we don't load freelist so that
 		 * we don't make further mismatched allocations easier.
-- 
2.33.1

[PATCH v2 17/33] mm/slub: Convert most struct page to struct slab by spatch

[Vlastimil Babka]

The majority of conversion from struct page to struct slab in SLUB internals
can be delegated to a coccinelle semantic patch. This includes renaming of
variables with 'page' in name to 'slab', and similar.

Big thanks to Julia Lawall and Luis Chamberlain for help with coccinelle.

// Options: --include-headers --no-includes --smpl-spacing include/linux/slub_def.h mm/slub.c
// Note: needs coccinelle 1.1.1 to avoid breaking whitespace, and ocaml for the
// embedded script script

// build list of functions to exclude from applying the next rule
@initialize:ocaml@
@@

let ok_function p =
  not (List.mem (List.hd p).current_element ["nearest_obj";"obj_to_index";"objs_per_slab_page";"__slab_lock";"__slab_unlock";"free_nonslab_page";"kmalloc_large_node"])

// convert the type from struct page to struct page in all functions except the
// list from previous rule
// this also affects struct kmem_cache_cpu, but that's ok
@@
position p : script:ocaml() { ok_function p };
@@

- struct page@p
+ struct slab

// in struct kmem_cache_cpu, change the name from page to slab
// the type was already converted by the previous rule
@@
@@

struct kmem_cache_cpu {
...
-struct slab *page;
+struct slab *slab;
...
}

// there are many places that use c->page which is now c->slab after the
// previous rule
@@
struct kmem_cache_cpu *c;
@@

-c->page
+c->slab

@@
@@

struct kmem_cache {
...
- unsigned int cpu_partial_pages;
+ unsigned int cpu_partial_slabs;
...
}

@@
struct kmem_cache *s;
@@

- s->cpu_partial_pages
+ s->cpu_partial_slabs

@@
@@

static void
- setup_page_debug(
+ setup_slab_debug(
 ...)
 {...}

@@
@@

- setup_page_debug(
+ setup_slab_debug(
 ...);

// for all functions (with exceptions), change any "struct slab *page"
// parameter to "struct slab *slab" in the signature, and generally all
// occurences of "page" to "slab" in the body - with some special cases.

@@
identifier fn !~ "free_nonslab_page|obj_to_index|objs_per_slab_page|nearest_obj";
@@
 fn(...,
-   struct slab *page
+   struct slab *slab
    ,...)
 {
<...
- page
+ slab
...>
 }

// similar to previous but the param is called partial_page
@@
identifier fn;
@@

 fn(...,
-   struct slab *partial_page
+   struct slab *partial_slab
    ,...)
 {
<...
- partial_page
+ partial_slab
...>
 }

// similar to previous but for functions that take pointer to struct page ptr
@@
identifier fn;
@@

 fn(...,
-   struct slab **ret_page
+   struct slab **ret_slab
    ,...)
 {
<...
- ret_page
+ ret_slab
...>
 }

// functions converted by previous rules that were temporarily called using
// slab_page(E) so we want to remove the wrapper now that they accept struct
// slab ptr directly
@@
identifier fn =~ "slab_free|do_slab_free";
expression E;
@@

 fn(...,
- slab_page(E)
+ E
  ,...)

// similar to previous but for another pattern
@@
identifier fn =~ "slab_pad_check|check_object";
@@

 fn(...,
- folio_page(folio, 0)
+ slab
  ,...)

// functions that were returning struct page ptr and now will return struct
// slab ptr, including slab_page() wrapper removal
@@
identifier fn =~ "allocate_slab|new_slab";
expression E;
@@

 static
-struct slab *
+struct slab *
 fn(...)
 {
<...
- slab_page(E)
+ E
...>
 }

// rename any former struct page * declarations
@@
@@

struct slab *
(
- page
+ slab
|
- partial_page
+ partial_slab
|
- oldpage
+ oldslab
)
;

// this has to be separate from previous rule as page and page2 appear at the
// same line
@@
@@

struct slab *
-page2
+slab2
;

// similar but with initial assignment
@@
expression E;
@@

struct slab *
(
- page
+ slab
|
- flush_page
+ flush_slab
|
- discard_page
+ slab_to_discard
|
- page_to_unfreeze
+ slab_to_unfreeze
)
= E;

// convert most of struct page to struct slab usage inside functions (with
// exceptions), including specific variable renames
@@
identifier fn !~ "nearest_obj|obj_to_index|objs_per_slab_page|__slab_(un)*lock|__free_slab|free_nonslab_page|kmalloc_large_node";
expression E;
@@

 fn(...)
 {
<...
(
- int pages;
+ int slabs;
|
- int pages = E;
+ int slabs = E;
|
- page
+ slab
|
- flush_page
+ flush_slab
|
- partial_page
+ partial_slab
|
- oldpage->pages
+ oldslab->slabs
|
- oldpage
+ oldslab
|
- unsigned int nr_pages;
+ unsigned int nr_slabs;
|
- nr_pages
+ nr_slabs
|
- unsigned int partial_pages = E;
+ unsigned int partial_slabs = E;
|
- partial_pages
+ partial_slabs
)
...>
 }

// this has to be split out from the previous rule so that lines containing
// multiple matching changes will be fully converted
@@
identifier fn !~ "nearest_obj|obj_to_index|objs_per_slab_page|__slab_(un)*lock|__free_slab|free_nonslab_page|kmalloc_large_node";
@@

 fn(...)
 {
<...
(
- slab->pages
+ slab->slabs
|
- pages
+ slabs
|
- page2
+ slab2
|
- discard_page
+ slab_to_discard
|
- page_to_unfreeze
+ slab_to_unfreeze
)
...>
 }

// after we simply changed all occurences of page to slab, some usages need
// adjustment for slab-specific functions, or use slab_page() wrapper
@@
identifier fn !~ "nearest_obj|obj_to_index|objs_per_slab_page|__slab_(un)*lock|__free_slab|free_nonslab_page|kmalloc_large_node";
@@

 fn(...)
 {
<...
(
- page_slab(slab)
+ slab
|
- kasan_poison_slab(slab)
+ kasan_poison_slab(slab_page(slab))
|
- page_address(slab)
+ slab_address(slab)
|
- page_size(slab)
+ slab_size(slab)
|
- PageSlab(slab)
+ folio_test_slab(slab_folio(slab))
|
- page_to_nid(slab)
+ slab_nid(slab)
|
- compound_order(slab)
+ slab_order(slab)
)
...>
 }

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Julia Lawall <julia.lawall@inria.fr>
Cc: Luis Chamberlain <mcgrof@kernel.org>
---
 include/linux/slub_def.h |   6 +-
 mm/slub.c                | 872 +++++++++++++++++++--------------------
 2 files changed, 439 insertions(+), 439 deletions(-)

diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 1ef68d4de9c0..00d99afe1c0e 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -48,9 +48,9 @@ enum stat_item {
 struct kmem_cache_cpu {
 	void **freelist;	/* Pointer to next available object */
 	unsigned long tid;	/* Globally unique transaction id */
-	struct page *page;	/* The slab from which we are allocating */
+	struct slab *slab;	/* The slab from which we are allocating */
 #ifdef CONFIG_SLUB_CPU_PARTIAL
-	struct page *partial;	/* Partially allocated frozen slabs */
+	struct slab *partial;	/* Partially allocated frozen slabs */
 #endif
 	local_lock_t lock;	/* Protects the fields above */
 #ifdef CONFIG_SLUB_STATS
@@ -100,7 +100,7 @@ struct kmem_cache {
 	/* Number of per cpu partial objects to keep around */
 	unsigned int cpu_partial;
 	/* Number of per cpu partial pages to keep around */
-	unsigned int cpu_partial_pages;
+	unsigned int cpu_partial_slabs;
 #endif
 	struct kmem_cache_order_objects oo;
 
diff --git a/mm/slub.c b/mm/slub.c
index 8224962c81aa..be46a7151e8c 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -417,7 +417,7 @@ static inline unsigned int oo_objects(struct kmem_cache_order_objects x)
 #ifdef CONFIG_SLUB_CPU_PARTIAL
 static void slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
 {
-	unsigned int nr_pages;
+	unsigned int nr_slabs;
 
 	s->cpu_partial = nr_objects;
 
@@ -427,8 +427,8 @@ static void slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
 	 * growth of the list. For simplicity we assume that the pages will
 	 * be half-full.
 	 */
-	nr_pages = DIV_ROUND_UP(nr_objects * 2, oo_objects(s->oo));
-	s->cpu_partial_pages = nr_pages;
+	nr_slabs = DIV_ROUND_UP(nr_objects * 2, oo_objects(s->oo));
+	s->cpu_partial_slabs = nr_slabs;
 }
 #else
 static inline void
@@ -456,16 +456,16 @@ static __always_inline void __slab_unlock(struct slab *slab)
 	__bit_spin_unlock(PG_locked, &page->flags);
 }
 
-static __always_inline void slab_lock(struct page *page, unsigned long *flags)
+static __always_inline void slab_lock(struct slab *slab, unsigned long *flags)
 {
 	if (IS_ENABLED(CONFIG_PREEMPT_RT))
 		local_irq_save(*flags);
-	__slab_lock(page_slab(page));
+	__slab_lock(slab);
 }
 
-static __always_inline void slab_unlock(struct page *page, unsigned long *flags)
+static __always_inline void slab_unlock(struct slab *slab, unsigned long *flags)
 {
-	__slab_unlock(page_slab(page));
+	__slab_unlock(slab);
 	if (IS_ENABLED(CONFIG_PREEMPT_RT))
 		local_irq_restore(*flags);
 }
@@ -475,7 +475,7 @@ static __always_inline void slab_unlock(struct page *page, unsigned long *flags)
  * by an _irqsave() lock variant. Except on PREEMPT_RT where locks are different
  * so we disable interrupts as part of slab_[un]lock().
  */
-static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
+static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct slab *slab,
 		void *freelist_old, unsigned long counters_old,
 		void *freelist_new, unsigned long counters_new,
 		const char *n)
@@ -485,7 +485,7 @@ static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page
 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
     defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
 	if (s->flags & __CMPXCHG_DOUBLE) {
-		if (cmpxchg_double(&page->freelist, &page->counters,
+		if (cmpxchg_double(&slab->freelist, &slab->counters,
 				   freelist_old, counters_old,
 				   freelist_new, counters_new))
 			return true;
@@ -495,15 +495,15 @@ static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page
 		/* init to 0 to prevent spurious warnings */
 		unsigned long flags = 0;
 
-		slab_lock(page, &flags);
-		if (page->freelist == freelist_old &&
-					page->counters == counters_old) {
-			page->freelist = freelist_new;
-			page->counters = counters_new;
-			slab_unlock(page, &flags);
+		slab_lock(slab, &flags);
+		if (slab->freelist == freelist_old &&
+					slab->counters == counters_old) {
+			slab->freelist = freelist_new;
+			slab->counters = counters_new;
+			slab_unlock(slab, &flags);
 			return true;
 		}
-		slab_unlock(page, &flags);
+		slab_unlock(slab, &flags);
 	}
 
 	cpu_relax();
@@ -516,7 +516,7 @@ static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page
 	return false;
 }
 
-static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
+static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct slab *slab,
 		void *freelist_old, unsigned long counters_old,
 		void *freelist_new, unsigned long counters_new,
 		const char *n)
@@ -524,7 +524,7 @@ static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
     defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
 	if (s->flags & __CMPXCHG_DOUBLE) {
-		if (cmpxchg_double(&page->freelist, &page->counters,
+		if (cmpxchg_double(&slab->freelist, &slab->counters,
 				   freelist_old, counters_old,
 				   freelist_new, counters_new))
 			return true;
@@ -534,16 +534,16 @@ static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
 		unsigned long flags;
 
 		local_irq_save(flags);
-		__slab_lock(page_slab(page));
-		if (page->freelist == freelist_old &&
-					page->counters == counters_old) {
-			page->freelist = freelist_new;
-			page->counters = counters_new;
-			__slab_unlock(page_slab(page));
+		__slab_lock(slab);
+		if (slab->freelist == freelist_old &&
+					slab->counters == counters_old) {
+			slab->freelist = freelist_new;
+			slab->counters = counters_new;
+			__slab_unlock(slab);
 			local_irq_restore(flags);
 			return true;
 		}
-		__slab_unlock(page_slab(page));
+		__slab_unlock(slab);
 		local_irq_restore(flags);
 	}
 
@@ -562,14 +562,14 @@ static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)];
 static DEFINE_RAW_SPINLOCK(object_map_lock);
 
 static void __fill_map(unsigned long *obj_map, struct kmem_cache *s,
-		       struct page *page)
+		       struct slab *slab)
 {
-	void *addr = page_address(page);
+	void *addr = slab_address(slab);
 	void *p;
 
-	bitmap_zero(obj_map, page->objects);
+	bitmap_zero(obj_map, slab->objects);
 
-	for (p = page->freelist; p; p = get_freepointer(s, p))
+	for (p = slab->freelist; p; p = get_freepointer(s, p))
 		set_bit(__obj_to_index(s, addr, p), obj_map);
 }
 
@@ -599,14 +599,14 @@ static inline bool slab_add_kunit_errors(void) { return false; }
  * Node listlock must be held to guarantee that the page does
  * not vanish from under us.
  */
-static unsigned long *get_map(struct kmem_cache *s, struct page *page)
+static unsigned long *get_map(struct kmem_cache *s, struct slab *slab)
 	__acquires(&object_map_lock)
 {
 	VM_BUG_ON(!irqs_disabled());
 
 	raw_spin_lock(&object_map_lock);
 
-	__fill_map(object_map, s, page);
+	__fill_map(object_map, s, slab);
 
 	return object_map;
 }
@@ -667,17 +667,17 @@ static inline void metadata_access_disable(void)
 
 /* Verify that a pointer has an address that is valid within a slab page */
 static inline int check_valid_pointer(struct kmem_cache *s,
-				struct page *page, void *object)
+				struct slab *slab, void *object)
 {
 	void *base;
 
 	if (!object)
 		return 1;
 
-	base = page_address(page);
+	base = slab_address(slab);
 	object = kasan_reset_tag(object);
 	object = restore_red_left(s, object);
-	if (object < base || object >= base + page->objects * s->size ||
+	if (object < base || object >= base + slab->objects * s->size ||
 		(object - base) % s->size) {
 		return 0;
 	}
@@ -827,14 +827,14 @@ static void slab_fix(struct kmem_cache *s, char *fmt, ...)
 	va_end(args);
 }
 
-static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
+static void print_trailer(struct kmem_cache *s, struct slab *slab, u8 *p)
 {
 	unsigned int off;	/* Offset of last byte */
-	u8 *addr = page_address(page);
+	u8 *addr = slab_address(slab);
 
 	print_tracking(s, p);
 
-	print_slab_info(page_slab(page));
+	print_slab_info(slab);
 
 	pr_err("Object 0x%p @offset=%tu fp=0x%p\n\n",
 	       p, p - addr, get_freepointer(s, p));
@@ -866,23 +866,23 @@ static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
 	dump_stack();
 }
 
-static void object_err(struct kmem_cache *s, struct page *page,
+static void object_err(struct kmem_cache *s, struct slab *slab,
 			u8 *object, char *reason)
 {
 	if (slab_add_kunit_errors())
 		return;
 
 	slab_bug(s, "%s", reason);
-	print_trailer(s, page, object);
+	print_trailer(s, slab, object);
 	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 }
 
-static bool freelist_corrupted(struct kmem_cache *s, struct page *page,
+static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
 			       void **freelist, void *nextfree)
 {
 	if ((s->flags & SLAB_CONSISTENCY_CHECKS) &&
-	    !check_valid_pointer(s, page, nextfree) && freelist) {
-		object_err(s, page, *freelist, "Freechain corrupt");
+	    !check_valid_pointer(s, slab, nextfree) && freelist) {
+		object_err(s, slab, *freelist, "Freechain corrupt");
 		*freelist = NULL;
 		slab_fix(s, "Isolate corrupted freechain");
 		return true;
@@ -891,7 +891,7 @@ static bool freelist_corrupted(struct kmem_cache *s, struct page *page,
 	return false;
 }
 
-static __printf(3, 4) void slab_err(struct kmem_cache *s, struct page *page,
+static __printf(3, 4) void slab_err(struct kmem_cache *s, struct slab *slab,
 			const char *fmt, ...)
 {
 	va_list args;
@@ -904,7 +904,7 @@ static __printf(3, 4) void slab_err(struct kmem_cache *s, struct page *page,
 	vsnprintf(buf, sizeof(buf), fmt, args);
 	va_end(args);
 	slab_bug(s, "%s", buf);
-	print_slab_info(page_slab(page));
+	print_slab_info(slab);
 	dump_stack();
 	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 }
@@ -932,13 +932,13 @@ static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
 	memset(from, data, to - from);
 }
 
-static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
+static int check_bytes_and_report(struct kmem_cache *s, struct slab *slab,
 			u8 *object, char *what,
 			u8 *start, unsigned int value, unsigned int bytes)
 {
 	u8 *fault;
 	u8 *end;
-	u8 *addr = page_address(page);
+	u8 *addr = slab_address(slab);
 
 	metadata_access_enable();
 	fault = memchr_inv(kasan_reset_tag(start), value, bytes);
@@ -957,7 +957,7 @@ static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
 	pr_err("0x%p-0x%p @offset=%tu. First byte 0x%x instead of 0x%x\n",
 					fault, end - 1, fault - addr,
 					fault[0], value);
-	print_trailer(s, page, object);
+	print_trailer(s, slab, object);
 	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
 
 skip_bug_print:
@@ -1003,7 +1003,7 @@ static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
  * may be used with merged slabcaches.
  */
 
-static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
+static int check_pad_bytes(struct kmem_cache *s, struct slab *slab, u8 *p)
 {
 	unsigned long off = get_info_end(s);	/* The end of info */
 
@@ -1016,12 +1016,12 @@ static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
 	if (size_from_object(s) == off)
 		return 1;
 
-	return check_bytes_and_report(s, page, p, "Object padding",
+	return check_bytes_and_report(s, slab, p, "Object padding",
 			p + off, POISON_INUSE, size_from_object(s) - off);
 }
 
 /* Check the pad bytes at the end of a slab page */
-static int slab_pad_check(struct kmem_cache *s, struct page *page)
+static int slab_pad_check(struct kmem_cache *s, struct slab *slab)
 {
 	u8 *start;
 	u8 *fault;
@@ -1033,8 +1033,8 @@ static int slab_pad_check(struct kmem_cache *s, struct page *page)
 	if (!(s->flags & SLAB_POISON))
 		return 1;
 
-	start = page_address(page);
-	length = page_size(page);
+	start = slab_address(slab);
+	length = slab_size(slab);
 	end = start + length;
 	remainder = length % s->size;
 	if (!remainder)
@@ -1049,7 +1049,7 @@ static int slab_pad_check(struct kmem_cache *s, struct page *page)
 	while (end > fault && end[-1] == POISON_INUSE)
 		end--;
 
-	slab_err(s, page, "Padding overwritten. 0x%p-0x%p @offset=%tu",
+	slab_err(s, slab, "Padding overwritten. 0x%p-0x%p @offset=%tu",
 			fault, end - 1, fault - start);
 	print_section(KERN_ERR, "Padding ", pad, remainder);
 
@@ -1057,23 +1057,23 @@ static int slab_pad_check(struct kmem_cache *s, struct page *page)
 	return 0;
 }
 
-static int check_object(struct kmem_cache *s, struct page *page,
+static int check_object(struct kmem_cache *s, struct slab *slab,
 					void *object, u8 val)
 {
 	u8 *p = object;
 	u8 *endobject = object + s->object_size;
 
 	if (s->flags & SLAB_RED_ZONE) {
-		if (!check_bytes_and_report(s, page, object, "Left Redzone",
+		if (!check_bytes_and_report(s, slab, object, "Left Redzone",
 			object - s->red_left_pad, val, s->red_left_pad))
 			return 0;
 
-		if (!check_bytes_and_report(s, page, object, "Right Redzone",
+		if (!check_bytes_and_report(s, slab, object, "Right Redzone",
 			endobject, val, s->inuse - s->object_size))
 			return 0;
 	} else {
 		if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
-			check_bytes_and_report(s, page, p, "Alignment padding",
+			check_bytes_and_report(s, slab, p, "Alignment padding",
 				endobject, POISON_INUSE,
 				s->inuse - s->object_size);
 		}
@@ -1081,15 +1081,15 @@ static int check_object(struct kmem_cache *s, struct page *page,
 
 	if (s->flags & SLAB_POISON) {
 		if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
-			(!check_bytes_and_report(s, page, p, "Poison", p,
+			(!check_bytes_and_report(s, slab, p, "Poison", p,
 					POISON_FREE, s->object_size - 1) ||
-			 !check_bytes_and_report(s, page, p, "End Poison",
+			 !check_bytes_and_report(s, slab, p, "End Poison",
 				p + s->object_size - 1, POISON_END, 1)))
 			return 0;
 		/*
 		 * check_pad_bytes cleans up on its own.
 		 */
-		check_pad_bytes(s, page, p);
+		check_pad_bytes(s, slab, p);
 	}
 
 	if (!freeptr_outside_object(s) && val == SLUB_RED_ACTIVE)
@@ -1100,8 +1100,8 @@ static int check_object(struct kmem_cache *s, struct page *page,
 		return 1;
 
 	/* Check free pointer validity */
-	if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
-		object_err(s, page, p, "Freepointer corrupt");
+	if (!check_valid_pointer(s, slab, get_freepointer(s, p))) {
+		object_err(s, slab, p, "Freepointer corrupt");
 		/*
 		 * No choice but to zap it and thus lose the remainder
 		 * of the free objects in this slab. May cause
@@ -1113,28 +1113,28 @@ static int check_object(struct kmem_cache *s, struct page *page,
 	return 1;
 }
 
-static int check_slab(struct kmem_cache *s, struct page *page)
+static int check_slab(struct kmem_cache *s, struct slab *slab)
 {
 	int maxobj;
 
-	if (!PageSlab(page)) {
-		slab_err(s, page, "Not a valid slab page");
+	if (!folio_test_slab(slab_folio(slab))) {
+		slab_err(s, slab, "Not a valid slab page");
 		return 0;
 	}
 
-	maxobj = order_objects(compound_order(page), s->size);
-	if (page->objects > maxobj) {
-		slab_err(s, page, "objects %u > max %u",
-			page->objects, maxobj);
+	maxobj = order_objects(slab_order(slab), s->size);
+	if (slab->objects > maxobj) {
+		slab_err(s, slab, "objects %u > max %u",
+			slab->objects, maxobj);
 		return 0;
 	}
-	if (page->inuse > page->objects) {
-		slab_err(s, page, "inuse %u > max %u",
-			page->inuse, page->objects);
+	if (slab->inuse > slab->objects) {
+		slab_err(s, slab, "inuse %u > max %u",
+			slab->inuse, slab->objects);
 		return 0;
 	}
 	/* Slab_pad_check fixes things up after itself */
-	slab_pad_check(s, page);
+	slab_pad_check(s, slab);
 	return 1;
 }
 
@@ -1142,26 +1142,26 @@ static int check_slab(struct kmem_cache *s, struct page *page)
  * Determine if a certain object on a page is on the freelist. Must hold the
  * slab lock to guarantee that the chains are in a consistent state.
  */
-static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
+static int on_freelist(struct kmem_cache *s, struct slab *slab, void *search)
 {
 	int nr = 0;
 	void *fp;
 	void *object = NULL;
 	int max_objects;
 
-	fp = page->freelist;
-	while (fp && nr <= page->objects) {
+	fp = slab->freelist;
+	while (fp && nr <= slab->objects) {
 		if (fp == search)
 			return 1;
-		if (!check_valid_pointer(s, page, fp)) {
+		if (!check_valid_pointer(s, slab, fp)) {
 			if (object) {
-				object_err(s, page, object,
+				object_err(s, slab, object,
 					"Freechain corrupt");
 				set_freepointer(s, object, NULL);
 			} else {
-				slab_err(s, page, "Freepointer corrupt");
-				page->freelist = NULL;
-				page->inuse = page->objects;
+				slab_err(s, slab, "Freepointer corrupt");
+				slab->freelist = NULL;
+				slab->inuse = slab->objects;
 				slab_fix(s, "Freelist cleared");
 				return 0;
 			}
@@ -1172,34 +1172,34 @@ static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
 		nr++;
 	}
 
-	max_objects = order_objects(compound_order(page), s->size);
+	max_objects = order_objects(slab_order(slab), s->size);
 	if (max_objects > MAX_OBJS_PER_PAGE)
 		max_objects = MAX_OBJS_PER_PAGE;
 
-	if (page->objects != max_objects) {
-		slab_err(s, page, "Wrong number of objects. Found %d but should be %d",
-			 page->objects, max_objects);
-		page->objects = max_objects;
+	if (slab->objects != max_objects) {
+		slab_err(s, slab, "Wrong number of objects. Found %d but should be %d",
+			 slab->objects, max_objects);
+		slab->objects = max_objects;
 		slab_fix(s, "Number of objects adjusted");
 	}
-	if (page->inuse != page->objects - nr) {
-		slab_err(s, page, "Wrong object count. Counter is %d but counted were %d",
-			 page->inuse, page->objects - nr);
-		page->inuse = page->objects - nr;
+	if (slab->inuse != slab->objects - nr) {
+		slab_err(s, slab, "Wrong object count. Counter is %d but counted were %d",
+			 slab->inuse, slab->objects - nr);
+		slab->inuse = slab->objects - nr;
 		slab_fix(s, "Object count adjusted");
 	}
 	return search == NULL;
 }
 
-static void trace(struct kmem_cache *s, struct page *page, void *object,
+static void trace(struct kmem_cache *s, struct slab *slab, void *object,
 								int alloc)
 {
 	if (s->flags & SLAB_TRACE) {
 		pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
 			s->name,
 			alloc ? "alloc" : "free",
-			object, page->inuse,
-			page->freelist);
+			object, slab->inuse,
+			slab->freelist);
 
 		if (!alloc)
 			print_section(KERN_INFO, "Object ", (void *)object,
@@ -1213,22 +1213,22 @@ static void trace(struct kmem_cache *s, struct page *page, void *object,
  * Tracking of fully allocated slabs for debugging purposes.
  */
 static void add_full(struct kmem_cache *s,
-	struct kmem_cache_node *n, struct page *page)
+	struct kmem_cache_node *n, struct slab *slab)
 {
 	if (!(s->flags & SLAB_STORE_USER))
 		return;
 
 	lockdep_assert_held(&n->list_lock);
-	list_add(&page->slab_list, &n->full);
+	list_add(&slab->slab_list, &n->full);
 }
 
-static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page)
+static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct slab *slab)
 {
 	if (!(s->flags & SLAB_STORE_USER))
 		return;
 
 	lockdep_assert_held(&n->list_lock);
-	list_del(&page->slab_list);
+	list_del(&slab->slab_list);
 }
 
 /* Tracking of the number of slabs for debugging purposes */
@@ -1268,7 +1268,7 @@ static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
 }
 
 /* Object debug checks for alloc/free paths */
-static void setup_object_debug(struct kmem_cache *s, struct page *page,
+static void setup_object_debug(struct kmem_cache *s, struct slab *slab,
 								void *object)
 {
 	if (!kmem_cache_debug_flags(s, SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON))
@@ -1279,89 +1279,89 @@ static void setup_object_debug(struct kmem_cache *s, struct page *page,
 }
 
 static
-void setup_page_debug(struct kmem_cache *s, struct page *page, void *addr)
+void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr)
 {
 	if (!kmem_cache_debug_flags(s, SLAB_POISON))
 		return;
 
 	metadata_access_enable();
-	memset(kasan_reset_tag(addr), POISON_INUSE, page_size(page));
+	memset(kasan_reset_tag(addr), POISON_INUSE, slab_size(slab));
 	metadata_access_disable();
 }
 
 static inline int alloc_consistency_checks(struct kmem_cache *s,
-					struct page *page, void *object)
+					struct slab *slab, void *object)
 {
-	if (!check_slab(s, page))
+	if (!check_slab(s, slab))
 		return 0;
 
-	if (!check_valid_pointer(s, page, object)) {
-		object_err(s, page, object, "Freelist Pointer check fails");
+	if (!check_valid_pointer(s, slab, object)) {
+		object_err(s, slab, object, "Freelist Pointer check fails");
 		return 0;
 	}
 
-	if (!check_object(s, page, object, SLUB_RED_INACTIVE))
+	if (!check_object(s, slab, object, SLUB_RED_INACTIVE))
 		return 0;
 
 	return 1;
 }
 
 static noinline int alloc_debug_processing(struct kmem_cache *s,
-					struct page *page,
+					struct slab *slab,
 					void *object, unsigned long addr)
 {
 	if (s->flags & SLAB_CONSISTENCY_CHECKS) {
-		if (!alloc_consistency_checks(s, page, object))
+		if (!alloc_consistency_checks(s, slab, object))
 			goto bad;
 	}
 
 	/* Success perform special debug activities for allocs */
 	if (s->flags & SLAB_STORE_USER)
 		set_track(s, object, TRACK_ALLOC, addr);
-	trace(s, page, object, 1);
+	trace(s, slab, object, 1);
 	init_object(s, object, SLUB_RED_ACTIVE);
 	return 1;
 
 bad:
-	if (PageSlab(page)) {
+	if (folio_test_slab(slab_folio(slab))) {
 		/*
 		 * If this is a slab page then lets do the best we can
 		 * to avoid issues in the future. Marking all objects
 		 * as used avoids touching the remaining objects.
 		 */
 		slab_fix(s, "Marking all objects used");
-		page->inuse = page->objects;
-		page->freelist = NULL;
+		slab->inuse = slab->objects;
+		slab->freelist = NULL;
 	}
 	return 0;
 }
 
 static inline int free_consistency_checks(struct kmem_cache *s,
-		struct page *page, void *object, unsigned long addr)
+		struct slab *slab, void *object, unsigned long addr)
 {
-	if (!check_valid_pointer(s, page, object)) {
-		slab_err(s, page, "Invalid object pointer 0x%p", object);
+	if (!check_valid_pointer(s, slab, object)) {
+		slab_err(s, slab, "Invalid object pointer 0x%p", object);
 		return 0;
 	}
 
-	if (on_freelist(s, page, object)) {
-		object_err(s, page, object, "Object already free");
+	if (on_freelist(s, slab, object)) {
+		object_err(s, slab, object, "Object already free");
 		return 0;
 	}
 
-	if (!check_object(s, page, object, SLUB_RED_ACTIVE))
+	if (!check_object(s, slab, object, SLUB_RED_ACTIVE))
 		return 0;
 
-	if (unlikely(s != page->slab_cache)) {
-		if (!PageSlab(page)) {
-			slab_err(s, page, "Attempt to free object(0x%p) outside of slab",
+	if (unlikely(s != slab->slab_cache)) {
+		if (!folio_test_slab(slab_folio(slab))) {
+			slab_err(s, slab, "Attempt to free object(0x%p) outside of slab",
 				 object);
-		} else if (!page->slab_cache) {
+		} else if (!slab->slab_cache) {
 			pr_err("SLUB <none>: no slab for object 0x%p.\n",
 			       object);
 			dump_stack();
 		} else
-			object_err(s, page, object,
+			object_err(s, slab, object,
 					"page slab pointer corrupt.");
 		return 0;
 	}
@@ -1370,21 +1370,21 @@ static inline int free_consistency_checks(struct kmem_cache *s,
 
 /* Supports checking bulk free of a constructed freelist */
 static noinline int free_debug_processing(
-	struct kmem_cache *s, struct page *page,
+	struct kmem_cache *s, struct slab *slab,
 	void *head, void *tail, int bulk_cnt,
 	unsigned long addr)
 {
-	struct kmem_cache_node *n = get_node(s, page_to_nid(page));
+	struct kmem_cache_node *n = get_node(s, slab_nid(slab));
 	void *object = head;
 	int cnt = 0;
 	unsigned long flags, flags2;
 	int ret = 0;
 
 	spin_lock_irqsave(&n->list_lock, flags);
-	slab_lock(page, &flags2);
+	slab_lock(slab, &flags2);
 
 	if (s->flags & SLAB_CONSISTENCY_CHECKS) {
-		if (!check_slab(s, page))
+		if (!check_slab(s, slab))
 			goto out;
 	}
 
@@ -1392,13 +1392,13 @@ static noinline int free_debug_processing(
 	cnt++;
 
 	if (s->flags & SLAB_CONSISTENCY_CHECKS) {
-		if (!free_consistency_checks(s, page, object, addr))
+		if (!free_consistency_checks(s, slab, object, addr))
 			goto out;
 	}
 
 	if (s->flags & SLAB_STORE_USER)
 		set_track(s, object, TRACK_FREE, addr);
-	trace(s, page, object, 0);
+	trace(s, slab, object, 0);
 	/* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
 	init_object(s, object, SLUB_RED_INACTIVE);
 
@@ -1411,10 +1411,10 @@ static noinline int free_debug_processing(
 
 out:
 	if (cnt != bulk_cnt)
-		slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n",
+		slab_err(s, slab, "Bulk freelist count(%d) invalid(%d)\n",
 			 bulk_cnt, cnt);
 
-	slab_unlock(page, &flags2);
+	slab_unlock(slab, &flags2);
 	spin_unlock_irqrestore(&n->list_lock, flags);
 	if (!ret)
 		slab_fix(s, "Object at 0x%p not freed", object);
@@ -1629,26 +1629,26 @@ slab_flags_t kmem_cache_flags(unsigned int object_size,
 }
 #else /* !CONFIG_SLUB_DEBUG */
 static inline void setup_object_debug(struct kmem_cache *s,
-			struct page *page, void *object) {}
+			struct slab *slab, void *object) {}
 static inline
-void setup_page_debug(struct kmem_cache *s, struct page *page, void *addr) {}
+void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr) {}
 
 static inline int alloc_debug_processing(struct kmem_cache *s,
-	struct page *page, void *object, unsigned long addr) { return 0; }
+	struct slab *slab, void *object, unsigned long addr) { return 0; }
 
 static inline int free_debug_processing(
-	struct kmem_cache *s, struct page *page,
+	struct kmem_cache *s, struct slab *slab,
 	void *head, void *tail, int bulk_cnt,
 	unsigned long addr) { return 0; }
 
-static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
+static inline int slab_pad_check(struct kmem_cache *s, struct slab *slab)
 			{ return 1; }
-static inline int check_object(struct kmem_cache *s, struct page *page,
+static inline int check_object(struct kmem_cache *s, struct slab *slab,
 			void *object, u8 val) { return 1; }
 static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
-					struct page *page) {}
+					struct slab *slab) {}
 static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
-					struct page *page) {}
+					struct slab *slab) {}
 slab_flags_t kmem_cache_flags(unsigned int object_size,
 	slab_flags_t flags, const char *name)
 {
@@ -1667,7 +1667,7 @@ static inline void inc_slabs_node(struct kmem_cache *s, int node,
 static inline void dec_slabs_node(struct kmem_cache *s, int node,
 							int objects) {}
 
-static bool freelist_corrupted(struct kmem_cache *s, struct page *page,
+static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
 			       void **freelist, void *nextfree)
 {
 	return false;
@@ -1772,10 +1772,10 @@ static inline bool slab_free_freelist_hook(struct kmem_cache *s,
 	return *head != NULL;
 }
 
-static void *setup_object(struct kmem_cache *s, struct page *page,
+static void *setup_object(struct kmem_cache *s, struct slab *slab,
 				void *object)
 {
-	setup_object_debug(s, page, object);
+	setup_object_debug(s, slab, object);
 	object = kasan_init_slab_obj(s, object);
 	if (unlikely(s->ctor)) {
 		kasan_unpoison_object_data(s, object);
@@ -1853,7 +1853,7 @@ static void __init init_freelist_randomization(void)
 }
 
 /* Get the next entry on the pre-computed freelist randomized */
-static void *next_freelist_entry(struct kmem_cache *s, struct page *page,
+static void *next_freelist_entry(struct kmem_cache *s, struct slab *slab,
 				unsigned long *pos, void *start,
 				unsigned long page_limit,
 				unsigned long freelist_count)
@@ -1875,32 +1875,32 @@ static void *next_freelist_entry(struct kmem_cache *s, struct page *page,
 }
 
 /* Shuffle the single linked freelist based on a random pre-computed sequence */
-static bool shuffle_freelist(struct kmem_cache *s, struct page *page)
+static bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
 {
 	void *start;
 	void *cur;
 	void *next;
 	unsigned long idx, pos, page_limit, freelist_count;
 
-	if (page->objects < 2 || !s->random_seq)
+	if (slab->objects < 2 || !s->random_seq)
 		return false;
 
 	freelist_count = oo_objects(s->oo);
 	pos = get_random_int() % freelist_count;
 
-	page_limit = page->objects * s->size;
-	start = fixup_red_left(s, page_address(page));
+	page_limit = slab->objects * s->size;
+	start = fixup_red_left(s, slab_address(slab));
 
 	/* First entry is used as the base of the freelist */
-	cur = next_freelist_entry(s, page, &pos, start, page_limit,
+	cur = next_freelist_entry(s, slab, &pos, start, page_limit,
 				freelist_count);
-	cur = setup_object(s, page, cur);
-	page->freelist = cur;
+	cur = setup_object(s, slab, cur);
+	slab->freelist = cur;
 
-	for (idx = 1; idx < page->objects; idx++) {
-		next = next_freelist_entry(s, page, &pos, start, page_limit,
+	for (idx = 1; idx < slab->objects; idx++) {
+		next = next_freelist_entry(s, slab, &pos, start, page_limit,
 			freelist_count);
-		next = setup_object(s, page, next);
+		next = setup_object(s, slab, next);
 		set_freepointer(s, cur, next);
 		cur = next;
 	}
@@ -1914,15 +1914,15 @@ static inline int init_cache_random_seq(struct kmem_cache *s)
 	return 0;
 }
 static inline void init_freelist_randomization(void) { }
-static inline bool shuffle_freelist(struct kmem_cache *s, struct page *page)
+static inline bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
 {
 	return false;
 }
 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
 
-static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
+static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 {
-	struct page *page;
+	struct slab *slab;
 	struct kmem_cache_order_objects oo = s->oo;
 	gfp_t alloc_gfp;
 	void *start, *p, *next;
@@ -1941,60 +1941,60 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 	if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
 		alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
 
-	page = slab_page(alloc_slab_page(s, alloc_gfp, node, oo));
-	if (unlikely(!page)) {
+	slab = alloc_slab_page(s, alloc_gfp, node, oo);
+	if (unlikely(!slab)) {
 		oo = s->min;
 		alloc_gfp = flags;
 		/*
 		 * Allocation may have failed due to fragmentation.
 		 * Try a lower order alloc if possible
 		 */
-		page = slab_page(alloc_slab_page(s, alloc_gfp, node, oo));
-		if (unlikely(!page))
+		slab = alloc_slab_page(s, alloc_gfp, node, oo);
+		if (unlikely(!slab))
 			goto out;
 		stat(s, ORDER_FALLBACK);
 	}
 
-	page->objects = oo_objects(oo);
+	slab->objects = oo_objects(oo);
 
-	account_slab(page_slab(page), oo_order(oo), s, flags);
+	account_slab(slab, oo_order(oo), s, flags);
 
-	page->slab_cache = s;
+	slab->slab_cache = s;
 
-	kasan_poison_slab(page);
+	kasan_poison_slab(slab_page(slab));
 
-	start = page_address(page);
+	start = slab_address(slab);
 
-	setup_page_debug(s, page, start);
+	setup_slab_debug(s, slab, start);
 
-	shuffle = shuffle_freelist(s, page);
+	shuffle = shuffle_freelist(s, slab);
 
 	if (!shuffle) {
 		start = fixup_red_left(s, start);
-		start = setup_object(s, page, start);
-		page->freelist = start;
-		for (idx = 0, p = start; idx < page->objects - 1; idx++) {
+		start = setup_object(s, slab, start);
+		slab->freelist = start;
+		for (idx = 0, p = start; idx < slab->objects - 1; idx++) {
 			next = p + s->size;
-			next = setup_object(s, page, next);
+			next = setup_object(s, slab, next);
 			set_freepointer(s, p, next);
 			p = next;
 		}
 		set_freepointer(s, p, NULL);
 	}
 
-	page->inuse = page->objects;
-	page->frozen = 1;
+	slab->inuse = slab->objects;
+	slab->frozen = 1;
 
 out:
-	if (!page)
+	if (!slab)
 		return NULL;
 
-	inc_slabs_node(s, page_to_nid(page), page->objects);
+	inc_slabs_node(s, slab_nid(slab), slab->objects);
 
-	return page;
+	return slab;
 }
 
-static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
+static struct slab *new_slab(struct kmem_cache *s, gfp_t flags, int node)
 {
 	if (unlikely(flags & GFP_SLAB_BUG_MASK))
 		flags = kmalloc_fix_flags(flags);
@@ -2014,9 +2014,9 @@ static void __free_slab(struct kmem_cache *s, struct slab *slab)
 	if (kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS)) {
 		void *p;
 
-		slab_pad_check(s, folio_page(folio, 0));
+		slab_pad_check(s, slab);
 		for_each_object(p, s, slab_address(slab), slab->objects)
-			check_object(s, folio_page(folio, 0), p, SLUB_RED_INACTIVE);
+			check_object(s, slab, p, SLUB_RED_INACTIVE);
 	}
 
 	__slab_clear_pfmemalloc(slab);
@@ -2031,50 +2031,50 @@ static void __free_slab(struct kmem_cache *s, struct slab *slab)
 
 static void rcu_free_slab(struct rcu_head *h)
 {
-	struct page *page = container_of(h, struct page, rcu_head);
+	struct slab *slab = container_of(h, struct slab, rcu_head);
 
-	__free_slab(page->slab_cache, page_slab(page));
+	__free_slab(slab->slab_cache, slab);
 }
 
-static void free_slab(struct kmem_cache *s, struct page *page)
+static void free_slab(struct kmem_cache *s, struct slab *slab)
 {
 	if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) {
-		call_rcu(&page->rcu_head, rcu_free_slab);
+		call_rcu(&slab->rcu_head, rcu_free_slab);
 	} else
-		__free_slab(s, page_slab(page));
+		__free_slab(s, slab);
 }
 
-static void discard_slab(struct kmem_cache *s, struct page *page)
+static void discard_slab(struct kmem_cache *s, struct slab *slab)
 {
-	dec_slabs_node(s, page_to_nid(page), page->objects);
-	free_slab(s, page);
+	dec_slabs_node(s, slab_nid(slab), slab->objects);
+	free_slab(s, slab);
 }
 
 /*
  * Management of partially allocated slabs.
  */
 static inline void
-__add_partial(struct kmem_cache_node *n, struct page *page, int tail)
+__add_partial(struct kmem_cache_node *n, struct slab *slab, int tail)
 {
 	n->nr_partial++;
 	if (tail == DEACTIVATE_TO_TAIL)
-		list_add_tail(&page->slab_list, &n->partial);
+		list_add_tail(&slab->slab_list, &n->partial);
 	else
-		list_add(&page->slab_list, &n->partial);
+		list_add(&slab->slab_list, &n->partial);
 }
 
 static inline void add_partial(struct kmem_cache_node *n,
-				struct page *page, int tail)
+				struct slab *slab, int tail)
 {
 	lockdep_assert_held(&n->list_lock);
-	__add_partial(n, page, tail);
+	__add_partial(n, slab, tail);
 }
 
 static inline void remove_partial(struct kmem_cache_node *n,
-					struct page *page)
+					struct slab *slab)
 {
 	lockdep_assert_held(&n->list_lock);
-	list_del(&page->slab_list);
+	list_del(&slab->slab_list);
 	n->nr_partial--;
 }
 
@@ -2085,12 +2085,12 @@ static inline void remove_partial(struct kmem_cache_node *n,
  * Returns a list of objects or NULL if it fails.
  */
 static inline void *acquire_slab(struct kmem_cache *s,
-		struct kmem_cache_node *n, struct page *page,
+		struct kmem_cache_node *n, struct slab *slab,
 		int mode)
 {
 	void *freelist;
 	unsigned long counters;
-	struct page new;
+	struct slab new;
 
 	lockdep_assert_held(&n->list_lock);
 
@@ -2099,11 +2099,11 @@ static inline void *acquire_slab(struct kmem_cache *s,
 	 * The old freelist is the list of objects for the
 	 * per cpu allocation list.
 	 */
-	freelist = page->freelist;
-	counters = page->counters;
+	freelist = slab->freelist;
+	counters = slab->counters;
 	new.counters = counters;
 	if (mode) {
-		new.inuse = page->objects;
+		new.inuse = slab->objects;
 		new.freelist = NULL;
 	} else {
 		new.freelist = freelist;
@@ -2112,21 +2112,21 @@ static inline void *acquire_slab(struct kmem_cache *s,
 	VM_BUG_ON(new.frozen);
 	new.frozen = 1;
 
-	if (!__cmpxchg_double_slab(s, page,
+	if (!__cmpxchg_double_slab(s, slab,
 			freelist, counters,
 			new.freelist, new.counters,
 			"acquire_slab"))
 		return NULL;
 
-	remove_partial(n, page);
+	remove_partial(n, slab);
 	WARN_ON(!freelist);
 	return freelist;
 }
 
 #ifdef CONFIG_SLUB_CPU_PARTIAL
-static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
+static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain);
 #else
-static inline void put_cpu_partial(struct kmem_cache *s, struct page *page,
+static inline void put_cpu_partial(struct kmem_cache *s, struct slab *slab,
 				   int drain) { }
 #endif
 static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags);
@@ -2135,12 +2135,12 @@ static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags);
  * Try to allocate a partial slab from a specific node.
  */
 static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
-			      struct page **ret_page, gfp_t gfpflags)
+			      struct slab **ret_slab, gfp_t gfpflags)
 {
-	struct page *page, *page2;
+	struct slab *slab, *slab2;
 	void *object = NULL;
 	unsigned long flags;
-	unsigned int partial_pages = 0;
+	unsigned int partial_slabs = 0;
 
 	/*
 	 * Racy check. If we mistakenly see no partial slabs then we
@@ -2152,28 +2152,28 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
 		return NULL;
 
 	spin_lock_irqsave(&n->list_lock, flags);
-	list_for_each_entry_safe(page, page2, &n->partial, slab_list) {
+	list_for_each_entry_safe(slab, slab2, &n->partial, slab_list) {
 		void *t;
 
-		if (!pfmemalloc_match(page_slab(page), gfpflags))
+		if (!pfmemalloc_match(slab, gfpflags))
 			continue;
 
-		t = acquire_slab(s, n, page, object == NULL);
+		t = acquire_slab(s, n, slab, object == NULL);
 		if (!t)
 			break;
 
 		if (!object) {
-			*ret_page = page;
+			*ret_slab = slab;
 			stat(s, ALLOC_FROM_PARTIAL);
 			object = t;
 		} else {
-			put_cpu_partial(s, page, 0);
+			put_cpu_partial(s, slab, 0);
 			stat(s, CPU_PARTIAL_NODE);
-			partial_pages++;
+			partial_slabs++;
 		}
 #ifdef CONFIG_SLUB_CPU_PARTIAL
 		if (!kmem_cache_has_cpu_partial(s)
-			|| partial_pages > s->cpu_partial_pages / 2)
+			|| partial_slabs > s->cpu_partial_slabs / 2)
 			break;
 #else
 		break;
@@ -2188,7 +2188,7 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
  * Get a page from somewhere. Search in increasing NUMA distances.
  */
 static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
-			     struct page **ret_page)
+			     struct slab **ret_slab)
 {
 #ifdef CONFIG_NUMA
 	struct zonelist *zonelist;
@@ -2230,7 +2230,7 @@ static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
 
 			if (n && cpuset_zone_allowed(zone, flags) &&
 					n->nr_partial > s->min_partial) {
-				object = get_partial_node(s, n, ret_page, flags);
+				object = get_partial_node(s, n, ret_slab, flags);
 				if (object) {
 					/*
 					 * Don't check read_mems_allowed_retry()
@@ -2252,7 +2252,7 @@ static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
  * Get a partial page, lock it and return it.
  */
 static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
-			 struct page **ret_page)
+			 struct slab **ret_slab)
 {
 	void *object;
 	int searchnode = node;
@@ -2260,11 +2260,11 @@ static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
 	if (node == NUMA_NO_NODE)
 		searchnode = numa_mem_id();
 
-	object = get_partial_node(s, get_node(s, searchnode), ret_page, flags);
+	object = get_partial_node(s, get_node(s, searchnode), ret_slab, flags);
 	if (object || node != NUMA_NO_NODE)
 		return object;
 
-	return get_any_partial(s, flags, ret_page);
+	return get_any_partial(s, flags, ret_slab);
 }
 
 #ifdef CONFIG_PREEMPTION
@@ -2346,20 +2346,20 @@ static void init_kmem_cache_cpus(struct kmem_cache *s)
  * Assumes the slab has been already safely taken away from kmem_cache_cpu
  * by the caller.
  */
-static void deactivate_slab(struct kmem_cache *s, struct page *page,
+static void deactivate_slab(struct kmem_cache *s, struct slab *slab,
 			    void *freelist)
 {
 	enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
-	struct kmem_cache_node *n = get_node(s, page_to_nid(page));
+	struct kmem_cache_node *n = get_node(s, slab_nid(slab));
 	int lock = 0, free_delta = 0;
 	enum slab_modes l = M_NONE, m = M_NONE;
 	void *nextfree, *freelist_iter, *freelist_tail;
 	int tail = DEACTIVATE_TO_HEAD;
 	unsigned long flags = 0;
-	struct page new;
-	struct page old;
+	struct slab new;
+	struct slab old;
 
-	if (page->freelist) {
+	if (slab->freelist) {
 		stat(s, DEACTIVATE_REMOTE_FREES);
 		tail = DEACTIVATE_TO_TAIL;
 	}
@@ -2378,7 +2378,7 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page,
 		 * 'freelist_iter' is already corrupted.  So isolate all objects
 		 * starting at 'freelist_iter' by skipping them.
 		 */
-		if (freelist_corrupted(s, page, &freelist_iter, nextfree))
+		if (freelist_corrupted(s, slab, &freelist_iter, nextfree))
 			break;
 
 		freelist_tail = freelist_iter;
@@ -2405,8 +2405,8 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page,
 	 */
 redo:
 
-	old.freelist = READ_ONCE(page->freelist);
-	old.counters = READ_ONCE(page->counters);
+	old.freelist = READ_ONCE(slab->freelist);
+	old.counters = READ_ONCE(slab->counters);
 	VM_BUG_ON(!old.frozen);
 
 	/* Determine target state of the slab */
@@ -2448,18 +2448,18 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page,
 
 	if (l != m) {
 		if (l == M_PARTIAL)
-			remove_partial(n, page);
+			remove_partial(n, slab);
 		else if (l == M_FULL)
-			remove_full(s, n, page);
+			remove_full(s, n, slab);
 
 		if (m == M_PARTIAL)
-			add_partial(n, page, tail);
+			add_partial(n, slab, tail);
 		else if (m == M_FULL)
-			add_full(s, n, page);
+			add_full(s, n, slab);
 	}
 
 	l = m;
-	if (!cmpxchg_double_slab(s, page,
+	if (!cmpxchg_double_slab(s, slab,
 				old.freelist, old.counters,
 				new.freelist, new.counters,
 				"unfreezing slab"))
@@ -2474,26 +2474,26 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page,
 		stat(s, DEACTIVATE_FULL);
 	else if (m == M_FREE) {
 		stat(s, DEACTIVATE_EMPTY);
-		discard_slab(s, page);
+		discard_slab(s, slab);
 		stat(s, FREE_SLAB);
 	}
 }
 
 #ifdef CONFIG_SLUB_CPU_PARTIAL
-static void __unfreeze_partials(struct kmem_cache *s, struct page *partial_page)
+static void __unfreeze_partials(struct kmem_cache *s, struct slab *partial_slab)
 {
 	struct kmem_cache_node *n = NULL, *n2 = NULL;
-	struct page *page, *discard_page = NULL;
+	struct slab *slab, *slab_to_discard = NULL;
 	unsigned long flags = 0;
 
-	while (partial_page) {
-		struct page new;
-		struct page old;
+	while (partial_slab) {
+		struct slab new;
+		struct slab old;
 
-		page = partial_page;
-		partial_page = page->next;
+		slab = partial_slab;
+		partial_slab = slab->next;
 
-		n2 = get_node(s, page_to_nid(page));
+		n2 = get_node(s, slab_nid(slab));
 		if (n != n2) {
 			if (n)
 				spin_unlock_irqrestore(&n->list_lock, flags);
@@ -2504,8 +2504,8 @@ static void __unfreeze_partials(struct kmem_cache *s, struct page *partial_page)
 
 		do {
 
-			old.freelist = page->freelist;
-			old.counters = page->counters;
+			old.freelist = slab->freelist;
+			old.counters = slab->counters;
 			VM_BUG_ON(!old.frozen);
 
 			new.counters = old.counters;
@@ -2513,16 +2513,16 @@ static void __unfreeze_partials(struct kmem_cache *s, struct page *partial_page)
 
 			new.frozen = 0;
 
-		} while (!__cmpxchg_double_slab(s, page,
+		} while (!__cmpxchg_double_slab(s, slab,
 				old.freelist, old.counters,
 				new.freelist, new.counters,
 				"unfreezing slab"));
 
 		if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) {
-			page->next = discard_page;
-			discard_page = page;
+			slab->next = slab_to_discard;
+			slab_to_discard = slab;
 		} else {
-			add_partial(n, page, DEACTIVATE_TO_TAIL);
+			add_partial(n, slab, DEACTIVATE_TO_TAIL);
 			stat(s, FREE_ADD_PARTIAL);
 		}
 	}
@@ -2530,12 +2530,12 @@ static void __unfreeze_partials(struct kmem_cache *s, struct page *partial_page)
 	if (n)
 		spin_unlock_irqrestore(&n->list_lock, flags);
 
-	while (discard_page) {
-		page = discard_page;
-		discard_page = discard_page->next;
+	while (slab_to_discard) {
+		slab = slab_to_discard;
+		slab_to_discard = slab_to_discard->next;
 
 		stat(s, DEACTIVATE_EMPTY);
-		discard_slab(s, page);
+		discard_slab(s, slab);
 		stat(s, FREE_SLAB);
 	}
 }
@@ -2545,28 +2545,28 @@ static void __unfreeze_partials(struct kmem_cache *s, struct page *partial_page)
  */
 static void unfreeze_partials(struct kmem_cache *s)
 {
-	struct page *partial_page;
+	struct slab *partial_slab;
 	unsigned long flags;
 
 	local_lock_irqsave(&s->cpu_slab->lock, flags);
-	partial_page = this_cpu_read(s->cpu_slab->partial);
+	partial_slab = this_cpu_read(s->cpu_slab->partial);
 	this_cpu_write(s->cpu_slab->partial, NULL);
 	local_unlock_irqrestore(&s->cpu_slab->lock, flags);
 
-	if (partial_page)
-		__unfreeze_partials(s, partial_page);
+	if (partial_slab)
+		__unfreeze_partials(s, partial_slab);
 }
 
 static void unfreeze_partials_cpu(struct kmem_cache *s,
 				  struct kmem_cache_cpu *c)
 {
-	struct page *partial_page;
+	struct slab *partial_slab;
 
-	partial_page = slub_percpu_partial(c);
+	partial_slab = slub_percpu_partial(c);
 	c->partial = NULL;
 
-	if (partial_page)
-		__unfreeze_partials(s, partial_page);
+	if (partial_slab)
+		__unfreeze_partials(s, partial_slab);
 }
 
 /*
@@ -2576,42 +2576,42 @@ static void unfreeze_partials_cpu(struct kmem_cache *s,
  * If we did not find a slot then simply move all the partials to the
  * per node partial list.
  */
-static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
+static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain)
 {
-	struct page *oldpage;
-	struct page *page_to_unfreeze = NULL;
+	struct slab *oldslab;
+	struct slab *slab_to_unfreeze = NULL;
 	unsigned long flags;
-	int pages = 0;
+	int slabs = 0;
 
 	local_lock_irqsave(&s->cpu_slab->lock, flags);
 
-	oldpage = this_cpu_read(s->cpu_slab->partial);
+	oldslab = this_cpu_read(s->cpu_slab->partial);
 
-	if (oldpage) {
-		if (drain && oldpage->pages >= s->cpu_partial_pages) {
+	if (oldslab) {
+		if (drain && oldslab->slabs >= s->cpu_partial_slabs) {
 			/*
 			 * Partial array is full. Move the existing set to the
 			 * per node partial list. Postpone the actual unfreezing
 			 * outside of the critical section.
 			 */
-			page_to_unfreeze = oldpage;
-			oldpage = NULL;
+			slab_to_unfreeze = oldslab;
+			oldslab = NULL;
 		} else {
-			pages = oldpage->pages;
+			slabs = oldslab->slabs;
 		}
 	}
 
-	pages++;
+	slabs++;
 
-	page->pages = pages;
-	page->next = oldpage;
+	slab->slabs = slabs;
+	slab->next = oldslab;
 
-	this_cpu_write(s->cpu_slab->partial, page);
+	this_cpu_write(s->cpu_slab->partial, slab);
 
 	local_unlock_irqrestore(&s->cpu_slab->lock, flags);
 
-	if (page_to_unfreeze) {
-		__unfreeze_partials(s, page_to_unfreeze);
+	if (slab_to_unfreeze) {
+		__unfreeze_partials(s, slab_to_unfreeze);
 		stat(s, CPU_PARTIAL_DRAIN);
 	}
 }
@@ -2627,22 +2627,22 @@ static inline void unfreeze_partials_cpu(struct kmem_cache *s,
 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
 {
 	unsigned long flags;
-	struct page *page;
+	struct slab *slab;
 	void *freelist;
 
 	local_lock_irqsave(&s->cpu_slab->lock, flags);
 
-	page = c->page;
+	slab = c->slab;
 	freelist = c->freelist;
 
-	c->page = NULL;
+	c->slab = NULL;
 	c->freelist = NULL;
 	c->tid = next_tid(c->tid);
 
 	local_unlock_irqrestore(&s->cpu_slab->lock, flags);
 
-	if (page) {
-		deactivate_slab(s, page, freelist);
+	if (slab) {
+		deactivate_slab(s, slab, freelist);
 		stat(s, CPUSLAB_FLUSH);
 	}
 }
@@ -2651,14 +2651,14 @@ static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
 {
 	struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
 	void *freelist = c->freelist;
-	struct page *page = c->page;
+	struct slab *slab = c->slab;
 
-	c->page = NULL;
+	c->slab = NULL;
 	c->freelist = NULL;
 	c->tid = next_tid(c->tid);
 
-	if (page) {
-		deactivate_slab(s, page, freelist);
+	if (slab) {
+		deactivate_slab(s, slab, freelist);
 		stat(s, CPUSLAB_FLUSH);
 	}
 
@@ -2687,7 +2687,7 @@ static void flush_cpu_slab(struct work_struct *w)
 	s = sfw->s;
 	c = this_cpu_ptr(s->cpu_slab);
 
-	if (c->page)
+	if (c->slab)
 		flush_slab(s, c);
 
 	unfreeze_partials(s);
@@ -2697,7 +2697,7 @@ static bool has_cpu_slab(int cpu, struct kmem_cache *s)
 {
 	struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
 
-	return c->page || slub_percpu_partial(c);
+	return c->slab || slub_percpu_partial(c);
 }
 
 static DEFINE_MUTEX(flush_lock);
@@ -2759,19 +2759,19 @@ static int slub_cpu_dead(unsigned int cpu)
  * Check if the objects in a per cpu structure fit numa
  * locality expectations.
  */
-static inline int node_match(struct page *page, int node)
+static inline int node_match(struct slab *slab, int node)
 {
 #ifdef CONFIG_NUMA
-	if (node != NUMA_NO_NODE && page_to_nid(page) != node)
+	if (node != NUMA_NO_NODE && slab_nid(slab) != node)
 		return 0;
 #endif
 	return 1;
 }
 
 #ifdef CONFIG_SLUB_DEBUG
-static int count_free(struct page *page)
+static int count_free(struct slab *slab)
 {
-	return page->objects - page->inuse;
+	return slab->objects - slab->inuse;
 }
 
 static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
@@ -2782,15 +2782,15 @@ static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
 
 #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
 static unsigned long count_partial(struct kmem_cache_node *n,
-					int (*get_count)(struct page *))
+					int (*get_count)(struct slab *))
 {
 	unsigned long flags;
 	unsigned long x = 0;
-	struct page *page;
+	struct slab *slab;
 
 	spin_lock_irqsave(&n->list_lock, flags);
-	list_for_each_entry(page, &n->partial, slab_list)
-		x += get_count(page);
+	list_for_each_entry(slab, &n->partial, slab_list)
+		x += get_count(slab);
 	spin_unlock_irqrestore(&n->list_lock, flags);
 	return x;
 }
@@ -2849,25 +2849,25 @@ static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags)
  *
  * If this function returns NULL then the page has been unfrozen.
  */
-static inline void *get_freelist(struct kmem_cache *s, struct page *page)
+static inline void *get_freelist(struct kmem_cache *s, struct slab *slab)
 {
-	struct page new;
+	struct slab new;
 	unsigned long counters;
 	void *freelist;
 
 	lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock));
 
 	do {
-		freelist = page->freelist;
-		counters = page->counters;
+		freelist = slab->freelist;
+		counters = slab->counters;
 
 		new.counters = counters;
 		VM_BUG_ON(!new.frozen);
 
-		new.inuse = page->objects;
+		new.inuse = slab->objects;
 		new.frozen = freelist != NULL;
 
-	} while (!__cmpxchg_double_slab(s, page,
+	} while (!__cmpxchg_double_slab(s, slab,
 		freelist, counters,
 		NULL, new.counters,
 		"get_freelist"));
@@ -2898,15 +2898,15 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 			  unsigned long addr, struct kmem_cache_cpu *c)
 {
 	void *freelist;
-	struct page *page;
+	struct slab *slab;
 	unsigned long flags;
 
 	stat(s, ALLOC_SLOWPATH);
 
 reread_page:
 
-	page = READ_ONCE(c->page);
-	if (!page) {
+	slab = READ_ONCE(c->slab);
+	if (!slab) {
 		/*
 		 * if the node is not online or has no normal memory, just
 		 * ignore the node constraint
@@ -2918,7 +2918,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 	}
 redo:
 
-	if (unlikely(!node_match(page, node))) {
+	if (unlikely(!node_match(slab, node))) {
 		/*
 		 * same as above but node_match() being false already
 		 * implies node != NUMA_NO_NODE
@@ -2937,12 +2937,12 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 	 * PFMEMALLOC but right now, we are losing the pfmemalloc
 	 * information when the page leaves the per-cpu allocator
 	 */
-	if (unlikely(!pfmemalloc_match(page_slab(page), gfpflags)))
+	if (unlikely(!pfmemalloc_match(slab, gfpflags)))
 		goto deactivate_slab;
 
 	/* must check again c->page in case we got preempted and it changed */
 	local_lock_irqsave(&s->cpu_slab->lock, flags);
-	if (unlikely(page != c->page)) {
+	if (unlikely(slab != c->slab)) {
 		local_unlock_irqrestore(&s->cpu_slab->lock, flags);
 		goto reread_page;
 	}
@@ -2950,10 +2950,10 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 	if (freelist)
 		goto load_freelist;
 
-	freelist = get_freelist(s, page);
+	freelist = get_freelist(s, slab);
 
 	if (!freelist) {
-		c->page = NULL;
+		c->slab = NULL;
 		local_unlock_irqrestore(&s->cpu_slab->lock, flags);
 		stat(s, DEACTIVATE_BYPASS);
 		goto new_slab;
@@ -2970,7 +2970,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 	 * page is pointing to the page from which the objects are obtained.
 	 * That page must be frozen for per cpu allocations to work.
 	 */
-	VM_BUG_ON(!c->page->frozen);
+	VM_BUG_ON(!c->slab->frozen);
 	c->freelist = get_freepointer(s, freelist);
 	c->tid = next_tid(c->tid);
 	local_unlock_irqrestore(&s->cpu_slab->lock, flags);
@@ -2979,21 +2979,21 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 deactivate_slab:
 
 	local_lock_irqsave(&s->cpu_slab->lock, flags);
-	if (page != c->page) {
+	if (slab != c->slab) {
 		local_unlock_irqrestore(&s->cpu_slab->lock, flags);
 		goto reread_page;
 	}
 	freelist = c->freelist;
-	c->page = NULL;
+	c->slab = NULL;
 	c->freelist = NULL;
 	local_unlock_irqrestore(&s->cpu_slab->lock, flags);
-	deactivate_slab(s, page, freelist);
+	deactivate_slab(s, slab, freelist);
 
 new_slab:
 
 	if (slub_percpu_partial(c)) {
 		local_lock_irqsave(&s->cpu_slab->lock, flags);
-		if (unlikely(c->page)) {
+		if (unlikely(c->slab)) {
 			local_unlock_irqrestore(&s->cpu_slab->lock, flags);
 			goto reread_page;
 		}
@@ -3003,8 +3003,8 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 			goto new_objects;
 		}
 
-		page = c->page = slub_percpu_partial(c);
-		slub_set_percpu_partial(c, page);
+		slab = c->slab = slub_percpu_partial(c);
+		slub_set_percpu_partial(c, slab);
 		local_unlock_irqrestore(&s->cpu_slab->lock, flags);
 		stat(s, CPU_PARTIAL_ALLOC);
 		goto redo;
@@ -3012,15 +3012,15 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 
 new_objects:
 
-	freelist = get_partial(s, gfpflags, node, &page);
+	freelist = get_partial(s, gfpflags, node, &slab);
 	if (freelist)
 		goto check_new_page;
 
 	slub_put_cpu_ptr(s->cpu_slab);
-	page = new_slab(s, gfpflags, node);
+	slab = new_slab(s, gfpflags, node);
 	c = slub_get_cpu_ptr(s->cpu_slab);
 
-	if (unlikely(!page)) {
+	if (unlikely(!slab)) {
 		slab_out_of_memory(s, gfpflags, node);
 		return NULL;
 	}
@@ -3029,15 +3029,15 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 	 * No other reference to the page yet so we can
 	 * muck around with it freely without cmpxchg
 	 */
-	freelist = page->freelist;
-	page->freelist = NULL;
+	freelist = slab->freelist;
+	slab->freelist = NULL;
 
 	stat(s, ALLOC_SLAB);
 
 check_new_page:
 
 	if (kmem_cache_debug(s)) {
-		if (!alloc_debug_processing(s, page, freelist, addr)) {
+		if (!alloc_debug_processing(s, slab, freelist, addr)) {
 			/* Slab failed checks. Next slab needed */
 			goto new_slab;
 		} else {
@@ -3049,7 +3049,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 		}
 	}
 
-	if (unlikely(!pfmemalloc_match(page_slab(page), gfpflags)))
+	if (unlikely(!pfmemalloc_match(slab, gfpflags)))
 		/*
 		 * For !pfmemalloc_match() case we don't load freelist so that
 		 * we don't make further mismatched allocations easier.
@@ -3059,29 +3059,29 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 retry_load_page:
 
 	local_lock_irqsave(&s->cpu_slab->lock, flags);
-	if (unlikely(c->page)) {
+	if (unlikely(c->slab)) {
 		void *flush_freelist = c->freelist;
-		struct page *flush_page = c->page;
+		struct slab *flush_slab = c->slab;
 
-		c->page = NULL;
+		c->slab = NULL;
 		c->freelist = NULL;
 		c->tid = next_tid(c->tid);
 
 		local_unlock_irqrestore(&s->cpu_slab->lock, flags);
 
-		deactivate_slab(s, flush_page, flush_freelist);
+		deactivate_slab(s, flush_slab, flush_freelist);
 
 		stat(s, CPUSLAB_FLUSH);
 
 		goto retry_load_page;
 	}
-	c->page = page;
+	c->slab = slab;
 
 	goto load_freelist;
 
 return_single:
 
-	deactivate_slab(s, page, get_freepointer(s, freelist));
+	deactivate_slab(s, slab, get_freepointer(s, freelist));
 	return freelist;
 }
 
@@ -3138,7 +3138,7 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s,
 {
 	void *object;
 	struct kmem_cache_cpu *c;
-	struct page *page;
+	struct slab *slab;
 	unsigned long tid;
 	struct obj_cgroup *objcg = NULL;
 	bool init = false;
@@ -3185,7 +3185,7 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s,
 	 */
 
 	object = c->freelist;
-	page = c->page;
+	slab = c->slab;
 	/*
 	 * We cannot use the lockless fastpath on PREEMPT_RT because if a
 	 * slowpath has taken the local_lock_irqsave(), it is not protected
@@ -3194,7 +3194,7 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s,
 	 * there is a suitable cpu freelist.
 	 */
 	if (IS_ENABLED(CONFIG_PREEMPT_RT) ||
-	    unlikely(!object || !page || !node_match(page, node))) {
+	    unlikely(!object || !slab || !node_match(slab, node))) {
 		object = __slab_alloc(s, gfpflags, node, addr, c);
 	} else {
 		void *next_object = get_freepointer_safe(s, object);
@@ -3299,14 +3299,14 @@ EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
  * lock and free the item. If there is no additional partial page
  * handling required then we can return immediately.
  */
-static void __slab_free(struct kmem_cache *s, struct page *page,
+static void __slab_free(struct kmem_cache *s, struct slab *slab,
 			void *head, void *tail, int cnt,
 			unsigned long addr)
 
 {
 	void *prior;
 	int was_frozen;
-	struct page new;
+	struct slab new;
 	unsigned long counters;
 	struct kmem_cache_node *n = NULL;
 	unsigned long flags;
@@ -3317,7 +3317,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
 		return;
 
 	if (kmem_cache_debug(s) &&
-	    !free_debug_processing(s, page, head, tail, cnt, addr))
+	    !free_debug_processing(s, slab, head, tail, cnt, addr))
 		return;
 
 	do {
@@ -3325,8 +3325,8 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
 			spin_unlock_irqrestore(&n->list_lock, flags);
 			n = NULL;
 		}
-		prior = page->freelist;
-		counters = page->counters;
+		prior = slab->freelist;
+		counters = slab->counters;
 		set_freepointer(s, tail, prior);
 		new.counters = counters;
 		was_frozen = new.frozen;
@@ -3345,7 +3345,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
 
 			} else { /* Needs to be taken off a list */
 
-				n = get_node(s, page_to_nid(page));
+				n = get_node(s, slab_nid(slab));
 				/*
 				 * Speculatively acquire the list_lock.
 				 * If the cmpxchg does not succeed then we may
@@ -3359,7 +3359,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
 			}
 		}
 
-	} while (!cmpxchg_double_slab(s, page,
+	} while (!cmpxchg_double_slab(s, slab,
 		prior, counters,
 		head, new.counters,
 		"__slab_free"));
@@ -3377,7 +3377,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
 			 * If we just froze the page then put it onto the
 			 * per cpu partial list.
 			 */
-			put_cpu_partial(s, page, 1);
+			put_cpu_partial(s, slab, 1);
 			stat(s, CPU_PARTIAL_FREE);
 		}
 
@@ -3392,8 +3392,8 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
 	 * then add it.
 	 */
 	if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
-		remove_full(s, n, page);
-		add_partial(n, page, DEACTIVATE_TO_TAIL);
+		remove_full(s, n, slab);
+		add_partial(n, slab, DEACTIVATE_TO_TAIL);
 		stat(s, FREE_ADD_PARTIAL);
 	}
 	spin_unlock_irqrestore(&n->list_lock, flags);
@@ -3404,16 +3404,16 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
 		/*
 		 * Slab on the partial list.
 		 */
-		remove_partial(n, page);
+		remove_partial(n, slab);
 		stat(s, FREE_REMOVE_PARTIAL);
 	} else {
 		/* Slab must be on the full list */
-		remove_full(s, n, page);
+		remove_full(s, n, slab);
 	}
 
 	spin_unlock_irqrestore(&n->list_lock, flags);
 	stat(s, FREE_SLAB);
-	discard_slab(s, page);
+	discard_slab(s, slab);
 }
 
 /*
@@ -3432,7 +3432,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
  * count (cnt). Bulk free indicated by tail pointer being set.
  */
 static __always_inline void do_slab_free(struct kmem_cache *s,
-				struct page *page, void *head, void *tail,
+				struct slab *slab, void *head, void *tail,
 				int cnt, unsigned long addr)
 {
 	void *tail_obj = tail ? : head;
@@ -3455,7 +3455,7 @@ static __always_inline void do_slab_free(struct kmem_cache *s,
 	/* Same with comment on barrier() in slab_alloc_node() */
 	barrier();
 
-	if (likely(page == c->page)) {
+	if (likely(slab == c->slab)) {
 #ifndef CONFIG_PREEMPT_RT
 		void **freelist = READ_ONCE(c->freelist);
 
@@ -3481,7 +3481,7 @@ static __always_inline void do_slab_free(struct kmem_cache *s,
 
 		local_lock(&s->cpu_slab->lock);
 		c = this_cpu_ptr(s->cpu_slab);
-		if (unlikely(page != c->page)) {
+		if (unlikely(slab != c->slab)) {
 			local_unlock(&s->cpu_slab->lock);
 			goto redo;
 		}
@@ -3496,11 +3496,11 @@ static __always_inline void do_slab_free(struct kmem_cache *s,
 #endif
 		stat(s, FREE_FASTPATH);
 	} else
-		__slab_free(s, page, head, tail_obj, cnt, addr);
+		__slab_free(s, slab, head, tail_obj, cnt, addr);
 
 }
 
-static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
+static __always_inline void slab_free(struct kmem_cache *s, struct slab *slab,
 				      void *head, void *tail, int cnt,
 				      unsigned long addr)
 {
@@ -3509,13 +3509,13 @@ static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
 	 * to remove objects, whose reuse must be delayed.
 	 */
 	if (slab_free_freelist_hook(s, &head, &tail, &cnt))
-		do_slab_free(s, page, head, tail, cnt, addr);
+		do_slab_free(s, slab, head, tail, cnt, addr);
 }
 
 #ifdef CONFIG_KASAN_GENERIC
 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
 {
-	do_slab_free(cache, slab_page(virt_to_slab(x)), x, NULL, 1, addr);
+	do_slab_free(cache, virt_to_slab(x), x, NULL, 1, addr);
 }
 #endif
 
@@ -3525,7 +3525,7 @@ void kmem_cache_free(struct kmem_cache *s, void *x)
 	if (!s)
 		return;
 	trace_kmem_cache_free(_RET_IP_, x, s->name);
-	slab_free(s, slab_page(virt_to_slab(x)), x, NULL, 1, _RET_IP_);
+	slab_free(s, virt_to_slab(x), x, NULL, 1, _RET_IP_);
 }
 EXPORT_SYMBOL(kmem_cache_free);
 
@@ -3654,7 +3654,7 @@ void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
 		if (!df.slab)
 			continue;
 
-		slab_free(df.s, slab_page(df.slab), df.freelist, df.tail, df.cnt, _RET_IP_);
+		slab_free(df.s, df.slab, df.freelist, df.tail, df.cnt, _RET_IP_);
 	} while (likely(size));
 }
 EXPORT_SYMBOL(kmem_cache_free_bulk);
@@ -3924,38 +3924,38 @@ static struct kmem_cache *kmem_cache_node;
  */
 static void early_kmem_cache_node_alloc(int node)
 {
-	struct page *page;
+	struct slab *slab;
 	struct kmem_cache_node *n;
 
 	BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
 
-	page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
+	slab = new_slab(kmem_cache_node, GFP_NOWAIT, node);
 
-	BUG_ON(!page);
-	if (page_to_nid(page) != node) {
+	BUG_ON(!slab);
+	if (slab_nid(slab) != node) {
 		pr_err("SLUB: Unable to allocate memory from node %d\n", node);
 		pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
 	}
 
-	n = page->freelist;
+	n = slab->freelist;
 	BUG_ON(!n);
 #ifdef CONFIG_SLUB_DEBUG
 	init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
 	init_tracking(kmem_cache_node, n);
 #endif
 	n = kasan_slab_alloc(kmem_cache_node, n, GFP_KERNEL, false);
-	page->freelist = get_freepointer(kmem_cache_node, n);
-	page->inuse = 1;
-	page->frozen = 0;
+	slab->freelist = get_freepointer(kmem_cache_node, n);
+	slab->inuse = 1;
+	slab->frozen = 0;
 	kmem_cache_node->node[node] = n;
 	init_kmem_cache_node(n);
-	inc_slabs_node(kmem_cache_node, node, page->objects);
+	inc_slabs_node(kmem_cache_node, node, slab->objects);
 
 	/*
 	 * No locks need to be taken here as it has just been
 	 * initialized and there is no concurrent access.
 	 */
-	__add_partial(n, page, DEACTIVATE_TO_HEAD);
+	__add_partial(n, slab, DEACTIVATE_TO_HEAD);
 }
 
 static void free_kmem_cache_nodes(struct kmem_cache *s)
@@ -4241,20 +4241,20 @@ static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
 	return -EINVAL;
 }
 
-static void list_slab_objects(struct kmem_cache *s, struct page *page,
+static void list_slab_objects(struct kmem_cache *s, struct slab *slab,
 			      const char *text)
 {
 #ifdef CONFIG_SLUB_DEBUG
-	void *addr = page_address(page);
+	void *addr = slab_address(slab);
 	unsigned long flags;
 	unsigned long *map;
 	void *p;
 
-	slab_err(s, page, text, s->name);
-	slab_lock(page, &flags);
+	slab_err(s, slab, text, s->name);
+	slab_lock(slab, &flags);
 
-	map = get_map(s, page);
-	for_each_object(p, s, addr, page->objects) {
+	map = get_map(s, slab);
+	for_each_object(p, s, addr, slab->objects) {
 
 		if (!test_bit(__obj_to_index(s, addr, p), map)) {
 			pr_err("Object 0x%p @offset=%tu\n", p, p - addr);
@@ -4262,7 +4262,7 @@ static void list_slab_objects(struct kmem_cache *s, struct page *page,
 		}
 	}
 	put_map(map);
-	slab_unlock(page, &flags);
+	slab_unlock(slab, &flags);
 #endif
 }
 
@@ -4274,23 +4274,23 @@ static void list_slab_objects(struct kmem_cache *s, struct page *page,
 static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
 {
 	LIST_HEAD(discard);
-	struct page *page, *h;
+	struct slab *slab, *h;
 
 	BUG_ON(irqs_disabled());
 	spin_lock_irq(&n->list_lock);
-	list_for_each_entry_safe(page, h, &n->partial, slab_list) {
-		if (!page->inuse) {
-			remove_partial(n, page);
-			list_add(&page->slab_list, &discard);
+	list_for_each_entry_safe(slab, h, &n->partial, slab_list) {
+		if (!slab->inuse) {
+			remove_partial(n, slab);
+			list_add(&slab->slab_list, &discard);
 		} else {
-			list_slab_objects(s, page,
+			list_slab_objects(s, slab,
 			  "Objects remaining in %s on __kmem_cache_shutdown()");
 		}
 	}
 	spin_unlock_irq(&n->list_lock);
 
-	list_for_each_entry_safe(page, h, &discard, slab_list)
-		discard_slab(s, page);
+	list_for_each_entry_safe(slab, h, &discard, slab_list)
+		discard_slab(s, slab);
 }
 
 bool __kmem_cache_empty(struct kmem_cache *s)
@@ -4559,7 +4559,7 @@ void kfree(const void *x)
 		return;
 	}
 	slab = folio_slab(folio);
-	slab_free(slab->slab_cache, slab_page(slab), object, NULL, 1, _RET_IP_);
+	slab_free(slab->slab_cache, slab, object, NULL, 1, _RET_IP_);
 }
 EXPORT_SYMBOL(kfree);
 
@@ -4579,8 +4579,8 @@ static int __kmem_cache_do_shrink(struct kmem_cache *s)
 	int node;
 	int i;
 	struct kmem_cache_node *n;
-	struct page *page;
-	struct page *t;
+	struct slab *slab;
+	struct slab *t;
 	struct list_head discard;
 	struct list_head promote[SHRINK_PROMOTE_MAX];
 	unsigned long flags;
@@ -4599,8 +4599,8 @@ static int __kmem_cache_do_shrink(struct kmem_cache *s)
 		 * Note that concurrent frees may occur while we hold the
 		 * list_lock. page->inuse here is the upper limit.
 		 */
-		list_for_each_entry_safe(page, t, &n->partial, slab_list) {
-			int free = page->objects - page->inuse;
+		list_for_each_entry_safe(slab, t, &n->partial, slab_list) {
+			int free = slab->objects - slab->inuse;
 
 			/* Do not reread page->inuse */
 			barrier();
@@ -4608,11 +4608,11 @@ static int __kmem_cache_do_shrink(struct kmem_cache *s)
 			/* We do not keep full slabs on the list */
 			BUG_ON(free <= 0);
 
-			if (free == page->objects) {
-				list_move(&page->slab_list, &discard);
+			if (free == slab->objects) {
+				list_move(&slab->slab_list, &discard);
 				n->nr_partial--;
 			} else if (free <= SHRINK_PROMOTE_MAX)
-				list_move(&page->slab_list, promote + free - 1);
+				list_move(&slab->slab_list, promote + free - 1);
 		}
 
 		/*
@@ -4625,8 +4625,8 @@ static int __kmem_cache_do_shrink(struct kmem_cache *s)
 		spin_unlock_irqrestore(&n->list_lock, flags);
 
 		/* Release empty slabs */
-		list_for_each_entry_safe(page, t, &discard, slab_list)
-			discard_slab(s, page);
+		list_for_each_entry_safe(slab, t, &discard, slab_list)
+			discard_slab(s, slab);
 
 		if (slabs_node(s, node))
 			ret = 1;
@@ -4787,7 +4787,7 @@ static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
 	 */
 	__flush_cpu_slab(s, smp_processor_id());
 	for_each_kmem_cache_node(s, node, n) {
-		struct page *p;
+		struct slab *p;
 
 		list_for_each_entry(p, &n->partial, slab_list)
 			p->slab_cache = s;
@@ -4965,54 +4965,54 @@ EXPORT_SYMBOL(__kmalloc_node_track_caller);
 #endif
 
 #ifdef CONFIG_SYSFS
-static int count_inuse(struct page *page)
+static int count_inuse(struct slab *slab)
 {
-	return page->inuse;
+	return slab->inuse;
 }
 
-static int count_total(struct page *page)
+static int count_total(struct slab *slab)
 {
-	return page->objects;
+	return slab->objects;
 }
 #endif
 
 #ifdef CONFIG_SLUB_DEBUG
-static void validate_slab(struct kmem_cache *s, struct page *page,
+static void validate_slab(struct kmem_cache *s, struct slab *slab,
 			  unsigned long *obj_map)
 {
 	void *p;
-	void *addr = page_address(page);
+	void *addr = slab_address(slab);
 	unsigned long flags;
 
-	slab_lock(page, &flags);
+	slab_lock(slab, &flags);
 
-	if (!check_slab(s, page) || !on_freelist(s, page, NULL))
+	if (!check_slab(s, slab) || !on_freelist(s, slab, NULL))
 		goto unlock;
 
 	/* Now we know that a valid freelist exists */
-	__fill_map(obj_map, s, page);
-	for_each_object(p, s, addr, page->objects) {
+	__fill_map(obj_map, s, slab);
+	for_each_object(p, s, addr, slab->objects) {
 		u8 val = test_bit(__obj_to_index(s, addr, p), obj_map) ?
 			 SLUB_RED_INACTIVE : SLUB_RED_ACTIVE;
 
-		if (!check_object(s, page, p, val))
+		if (!check_object(s, slab, p, val))
 			break;
 	}
 unlock:
-	slab_unlock(page, &flags);
+	slab_unlock(slab, &flags);
 }
 
 static int validate_slab_node(struct kmem_cache *s,
 		struct kmem_cache_node *n, unsigned long *obj_map)
 {
 	unsigned long count = 0;
-	struct page *page;
+	struct slab *slab;
 	unsigned long flags;
 
 	spin_lock_irqsave(&n->list_lock, flags);
 
-	list_for_each_entry(page, &n->partial, slab_list) {
-		validate_slab(s, page, obj_map);
+	list_for_each_entry(slab, &n->partial, slab_list) {
+		validate_slab(s, slab, obj_map);
 		count++;
 	}
 	if (count != n->nr_partial) {
@@ -5024,8 +5024,8 @@ static int validate_slab_node(struct kmem_cache *s,
 	if (!(s->flags & SLAB_STORE_USER))
 		goto out;
 
-	list_for_each_entry(page, &n->full, slab_list) {
-		validate_slab(s, page, obj_map);
+	list_for_each_entry(slab, &n->full, slab_list) {
+		validate_slab(s, slab, obj_map);
 		count++;
 	}
 	if (count != atomic_long_read(&n->nr_slabs)) {
@@ -5190,15 +5190,15 @@ static int add_location(struct loc_track *t, struct kmem_cache *s,
 }
 
 static void process_slab(struct loc_track *t, struct kmem_cache *s,
-		struct page *page, enum track_item alloc,
+		struct slab *slab, enum track_item alloc,
 		unsigned long *obj_map)
 {
-	void *addr = page_address(page);
+	void *addr = slab_address(slab);
 	void *p;
 
-	__fill_map(obj_map, s, page);
+	__fill_map(obj_map, s, slab);
 
-	for_each_object(p, s, addr, page->objects)
+	for_each_object(p, s, addr, slab->objects)
 		if (!test_bit(__obj_to_index(s, addr, p), obj_map))
 			add_location(t, s, get_track(s, p, alloc));
 }
@@ -5240,32 +5240,32 @@ static ssize_t show_slab_objects(struct kmem_cache *s,
 			struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
 							       cpu);
 			int node;
-			struct page *page;
+			struct slab *slab;
 
-			page = READ_ONCE(c->page);
-			if (!page)
+			slab = READ_ONCE(c->slab);
+			if (!slab)
 				continue;
 
-			node = page_to_nid(page);
+			node = slab_nid(slab);
 			if (flags & SO_TOTAL)
-				x = page->objects;
+				x = slab->objects;
 			else if (flags & SO_OBJECTS)
-				x = page->inuse;
+				x = slab->inuse;
 			else
 				x = 1;
 
 			total += x;
 			nodes[node] += x;
 
-			page = slub_percpu_partial_read_once(c);
-			if (page) {
-				node = page_to_nid(page);
+			slab = slub_percpu_partial_read_once(c);
+			if (slab) {
+				node = slab_nid(slab);
 				if (flags & SO_TOTAL)
 					WARN_ON_ONCE(1);
 				else if (flags & SO_OBJECTS)
 					WARN_ON_ONCE(1);
 				else
-					x = page->pages;
+					x = slab->slabs;
 				total += x;
 				nodes[node] += x;
 			}
@@ -5467,33 +5467,33 @@ SLAB_ATTR_RO(objects_partial);
 static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
 {
 	int objects = 0;
-	int pages = 0;
+	int slabs = 0;
 	int cpu;
 	int len = 0;
 
 	for_each_online_cpu(cpu) {
-		struct page *page;
+		struct slab *slab;
 
-		page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
+		slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
 
-		if (page)
-			pages += page->pages;
+		if (slab)
+			slabs += slab->slabs;
 	}
 
 	/* Approximate half-full pages , see slub_set_cpu_partial() */
-	objects = (pages * oo_objects(s->oo)) / 2;
-	len += sysfs_emit_at(buf, len, "%d(%d)", objects, pages);
+	objects = (slabs * oo_objects(s->oo)) / 2;
+	len += sysfs_emit_at(buf, len, "%d(%d)", objects, slabs);
 
 #ifdef CONFIG_SMP
 	for_each_online_cpu(cpu) {
-		struct page *page;
+		struct slab *slab;
 
-		page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
-		if (page) {
-			pages = READ_ONCE(page->pages);
-			objects = (pages * oo_objects(s->oo)) / 2;
+		slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
+		if (slab) {
+			slabs = READ_ONCE(slab->slabs);
+			objects = (slabs * oo_objects(s->oo)) / 2;
 			len += sysfs_emit_at(buf, len, " C%d=%d(%d)",
-					     cpu, objects, pages);
+					     cpu, objects, slabs);
 		}
 	}
 #endif
@@ -6159,16 +6159,16 @@ static int slab_debug_trace_open(struct inode *inode, struct file *filep)
 
 	for_each_kmem_cache_node(s, node, n) {
 		unsigned long flags;
-		struct page *page;
+		struct slab *slab;
 
 		if (!atomic_long_read(&n->nr_slabs))
 			continue;
 
 		spin_lock_irqsave(&n->list_lock, flags);
-		list_for_each_entry(page, &n->partial, slab_list)
-			process_slab(t, s, page, alloc, obj_map);
-		list_for_each_entry(page, &n->full, slab_list)
-			process_slab(t, s, page, alloc, obj_map);
+		list_for_each_entry(slab, &n->partial, slab_list)
+			process_slab(t, s, slab, alloc, obj_map);
+		list_for_each_entry(slab, &n->full, slab_list)
+			process_slab(t, s, slab, alloc, obj_map);
 		spin_unlock_irqrestore(&n->list_lock, flags);
 	}
 
-- 
2.33.1

[PATCH v2 18/33] mm/slub: Finish struct page to struct slab conversion

[Vlastimil Babka]

Update comments mentioning pages to mention slabs where appropriate. Also some
goto labels.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 include/linux/slub_def.h |   2 +-
 mm/slub.c                | 105 +++++++++++++++++++--------------------
 2 files changed, 53 insertions(+), 54 deletions(-)

diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 00d99afe1c0e..8a9c2876ca89 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -99,7 +99,7 @@ struct kmem_cache {
 #ifdef CONFIG_SLUB_CPU_PARTIAL
 	/* Number of per cpu partial objects to keep around */
 	unsigned int cpu_partial;
-	/* Number of per cpu partial pages to keep around */
+	/* Number of per cpu partial slabs to keep around */
 	unsigned int cpu_partial_slabs;
 #endif
 	struct kmem_cache_order_objects oo;
diff --git a/mm/slub.c b/mm/slub.c
index be46a7151e8c..f5344211d8cc 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -48,7 +48,7 @@
  *   1. slab_mutex (Global Mutex)
  *   2. node->list_lock (Spinlock)
  *   3. kmem_cache->cpu_slab->lock (Local lock)
- *   4. slab_lock(page) (Only on some arches or for debugging)
+ *   4. slab_lock(slab) (Only on some arches or for debugging)
  *   5. object_map_lock (Only for debugging)
  *
  *   slab_mutex
@@ -64,19 +64,19 @@
  *
  *   The slab_lock is only used for debugging and on arches that do not
  *   have the ability to do a cmpxchg_double. It only protects:
- *	A. page->freelist	-> List of object free in a page
- *	B. page->inuse		-> Number of objects in use
- *	C. page->objects	-> Number of objects in page
- *	D. page->frozen		-> frozen state
+ *	A. slab->freelist	-> List of free objects in a slab
+ *	B. slab->inuse		-> Number of objects in use
+ *	C. slab->objects	-> Number of objects in slab
+ *	D. slab->frozen		-> frozen state
  *
  *   Frozen slabs
  *
  *   If a slab is frozen then it is exempt from list management. It is not
  *   on any list except per cpu partial list. The processor that froze the
- *   slab is the one who can perform list operations on the page. Other
+ *   slab is the one who can perform list operations on the slab. Other
  *   processors may put objects onto the freelist but the processor that
  *   froze the slab is the only one that can retrieve the objects from the
- *   page's freelist.
+ *   slab's freelist.
  *
  *   list_lock
  *
@@ -135,7 +135,7 @@
  * minimal so we rely on the page allocators per cpu caches for
  * fast frees and allocs.
  *
- * page->frozen		The slab is frozen and exempt from list processing.
+ * slab->frozen		The slab is frozen and exempt from list processing.
  * 			This means that the slab is dedicated to a purpose
  * 			such as satisfying allocations for a specific
  * 			processor. Objects may be freed in the slab while
@@ -250,7 +250,7 @@ static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
 
 #define OO_SHIFT	16
 #define OO_MASK		((1 << OO_SHIFT) - 1)
-#define MAX_OBJS_PER_PAGE	32767 /* since page.objects is u15 */
+#define MAX_OBJS_PER_PAGE	32767 /* since slab.objects is u15 */
 
 /* Internal SLUB flags */
 /* Poison object */
@@ -423,8 +423,8 @@ static void slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
 
 	/*
 	 * We take the number of objects but actually limit the number of
-	 * pages on the per cpu partial list, in order to limit excessive
-	 * growth of the list. For simplicity we assume that the pages will
+	 * slabs on the per cpu partial list, in order to limit excessive
+	 * growth of the list. For simplicity we assume that the slabs will
 	 * be half-full.
 	 */
 	nr_slabs = DIV_ROUND_UP(nr_objects * 2, oo_objects(s->oo));
@@ -594,9 +594,9 @@ static inline bool slab_add_kunit_errors(void) { return false; }
 #endif
 
 /*
- * Determine a map of object in use on a page.
+ * Determine a map of objects in use in a slab.
  *
- * Node listlock must be held to guarantee that the page does
+ * Node listlock must be held to guarantee that the slab does
  * not vanish from under us.
  */
 static unsigned long *get_map(struct kmem_cache *s, struct slab *slab)
@@ -1139,7 +1139,7 @@ static int check_slab(struct kmem_cache *s, struct slab *slab)
 }
 
 /*
- * Determine if a certain object on a page is on the freelist. Must hold the
+ * Determine if a certain object in a slab is on the freelist. Must hold the
  * slab lock to guarantee that the chains are in a consistent state.
  */
 static int on_freelist(struct kmem_cache *s, struct slab *slab, void *search)
@@ -2185,7 +2185,7 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
 }
 
 /*
- * Get a page from somewhere. Search in increasing NUMA distances.
+ * Get a slab from somewhere. Search in increasing NUMA distances.
  */
 static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
 			     struct slab **ret_slab)
@@ -2249,7 +2249,7 @@ static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
 }
 
 /*
- * Get a partial page, lock it and return it.
+ * Get a partial slab, lock it and return it.
  */
 static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
 			 struct slab **ret_slab)
@@ -2341,7 +2341,7 @@ static void init_kmem_cache_cpus(struct kmem_cache *s)
 }
 
 /*
- * Finishes removing the cpu slab. Merges cpu's freelist with page's freelist,
+ * Finishes removing the cpu slab. Merges cpu's freelist with slab's freelist,
  * unfreezes the slabs and puts it on the proper list.
  * Assumes the slab has been already safely taken away from kmem_cache_cpu
  * by the caller.
@@ -2388,18 +2388,18 @@ static void deactivate_slab(struct kmem_cache *s, struct slab *slab,
 	}
 
 	/*
-	 * Stage two: Unfreeze the page while splicing the per-cpu
-	 * freelist to the head of page's freelist.
+	 * Stage two: Unfreeze the slab while splicing the per-cpu
+	 * freelist to the head of slab's freelist.
 	 *
-	 * Ensure that the page is unfrozen while the list presence
+	 * Ensure that the slab is unfrozen while the list presence
 	 * reflects the actual number of objects during unfreeze.
 	 *
 	 * We setup the list membership and then perform a cmpxchg
-	 * with the count. If there is a mismatch then the page
-	 * is not unfrozen but the page is on the wrong list.
+	 * with the count. If there is a mismatch then the slab
+	 * is not unfrozen but the slab is on the wrong list.
 	 *
 	 * Then we restart the process which may have to remove
-	 * the page from the list that we just put it on again
+	 * the slab from the list that we just put it on again
 	 * because the number of objects in the slab may have
 	 * changed.
 	 */
@@ -2427,9 +2427,8 @@ static void deactivate_slab(struct kmem_cache *s, struct slab *slab,
 		if (!lock) {
 			lock = 1;
 			/*
-			 * Taking the spinlock removes the possibility
-			 * that acquire_slab() will see a slab page that
-			 * is frozen
+			 * Taking the spinlock removes the possibility that
+			 * acquire_slab() will see a slab that is frozen
 			 */
 			spin_lock_irqsave(&n->list_lock, flags);
 		}
@@ -2570,8 +2569,8 @@ static void unfreeze_partials_cpu(struct kmem_cache *s,
 }
 
 /*
- * Put a page that was just frozen (in __slab_free|get_partial_node) into a
- * partial page slot if available.
+ * Put a slab that was just frozen (in __slab_free|get_partial_node) into a
+ * partial slab slot if available.
  *
  * If we did not find a slot then simply move all the partials to the
  * per node partial list.
@@ -2842,12 +2841,12 @@ static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags)
 }
 
 /*
- * Check the page->freelist of a page and either transfer the freelist to the
- * per cpu freelist or deactivate the page.
+ * Check the slab->freelist and either transfer the freelist to the
+ * per cpu freelist or deactivate the slab.
  *
- * The page is still frozen if the return value is not NULL.
+ * The slab is still frozen if the return value is not NULL.
  *
- * If this function returns NULL then the page has been unfrozen.
+ * If this function returns NULL then the slab has been unfrozen.
  */
 static inline void *get_freelist(struct kmem_cache *s, struct slab *slab)
 {
@@ -2903,7 +2902,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 
 	stat(s, ALLOC_SLOWPATH);
 
-reread_page:
+reread_slab:
 
 	slab = READ_ONCE(c->slab);
 	if (!slab) {
@@ -2940,11 +2939,11 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 	if (unlikely(!pfmemalloc_match(slab, gfpflags)))
 		goto deactivate_slab;
 
-	/* must check again c->page in case we got preempted and it changed */
+	/* must check again c->slab in case we got preempted and it changed */
 	local_lock_irqsave(&s->cpu_slab->lock, flags);
 	if (unlikely(slab != c->slab)) {
 		local_unlock_irqrestore(&s->cpu_slab->lock, flags);
-		goto reread_page;
+		goto reread_slab;
 	}
 	freelist = c->freelist;
 	if (freelist)
@@ -2967,8 +2966,8 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 
 	/*
 	 * freelist is pointing to the list of objects to be used.
-	 * page is pointing to the page from which the objects are obtained.
-	 * That page must be frozen for per cpu allocations to work.
+	 * slab is pointing to the slab from which the objects are obtained.
+	 * That slab must be frozen for per cpu allocations to work.
 	 */
 	VM_BUG_ON(!c->slab->frozen);
 	c->freelist = get_freepointer(s, freelist);
@@ -2981,7 +2980,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 	local_lock_irqsave(&s->cpu_slab->lock, flags);
 	if (slab != c->slab) {
 		local_unlock_irqrestore(&s->cpu_slab->lock, flags);
-		goto reread_page;
+		goto reread_slab;
 	}
 	freelist = c->freelist;
 	c->slab = NULL;
@@ -2995,7 +2994,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 		local_lock_irqsave(&s->cpu_slab->lock, flags);
 		if (unlikely(c->slab)) {
 			local_unlock_irqrestore(&s->cpu_slab->lock, flags);
-			goto reread_page;
+			goto reread_slab;
 		}
 		if (unlikely(!slub_percpu_partial(c))) {
 			local_unlock_irqrestore(&s->cpu_slab->lock, flags);
@@ -3014,7 +3013,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 
 	freelist = get_partial(s, gfpflags, node, &slab);
 	if (freelist)
-		goto check_new_page;
+		goto check_new_slab;
 
 	slub_put_cpu_ptr(s->cpu_slab);
 	slab = new_slab(s, gfpflags, node);
@@ -3026,7 +3025,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 	}
 
 	/*
-	 * No other reference to the page yet so we can
+	 * No other reference to the slab yet so we can
 	 * muck around with it freely without cmpxchg
 	 */
 	freelist = slab->freelist;
@@ -3034,7 +3033,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 
 	stat(s, ALLOC_SLAB);
 
-check_new_page:
+check_new_slab:
 
 	if (kmem_cache_debug(s)) {
 		if (!alloc_debug_processing(s, slab, freelist, addr)) {
@@ -3056,7 +3055,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 		 */
 		goto return_single;
 
-retry_load_page:
+retry_load_slab:
 
 	local_lock_irqsave(&s->cpu_slab->lock, flags);
 	if (unlikely(c->slab)) {
@@ -3073,7 +3072,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 
 		stat(s, CPUSLAB_FLUSH);
 
-		goto retry_load_page;
+		goto retry_load_slab;
 	}
 	c->slab = slab;
 
@@ -3170,9 +3169,9 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s,
 	/*
 	 * Irqless object alloc/free algorithm used here depends on sequence
 	 * of fetching cpu_slab's data. tid should be fetched before anything
-	 * on c to guarantee that object and page associated with previous tid
+	 * on c to guarantee that object and slab associated with previous tid
 	 * won't be used with current tid. If we fetch tid first, object and
-	 * page could be one associated with next tid and our alloc/free
+	 * slab could be one associated with next tid and our alloc/free
 	 * request will be failed. In this case, we will retry. So, no problem.
 	 */
 	barrier();
@@ -3296,7 +3295,7 @@ EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
  * have a longer lifetime than the cpu slabs in most processing loads.
  *
  * So we still attempt to reduce cache line usage. Just take the slab
- * lock and free the item. If there is no additional partial page
+ * lock and free the item. If there is no additional partial slab
  * handling required then we can return immediately.
  */
 static void __slab_free(struct kmem_cache *s, struct slab *slab,
@@ -3374,7 +3373,7 @@ static void __slab_free(struct kmem_cache *s, struct slab *slab,
 			stat(s, FREE_FROZEN);
 		} else if (new.frozen) {
 			/*
-			 * If we just froze the page then put it onto the
+			 * If we just froze the slab then put it onto the
 			 * per cpu partial list.
 			 */
 			put_cpu_partial(s, slab, 1);
@@ -3428,7 +3427,7 @@ static void __slab_free(struct kmem_cache *s, struct slab *slab,
  * with all sorts of special processing.
  *
  * Bulk free of a freelist with several objects (all pointing to the
- * same page) possible by specifying head and tail ptr, plus objects
+ * same slab) possible by specifying head and tail ptr, plus objects
  * count (cnt). Bulk free indicated by tail pointer being set.
  */
 static __always_inline void do_slab_free(struct kmem_cache *s,
@@ -4213,7 +4212,7 @@ static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
 #endif
 
 	/*
-	 * The larger the object size is, the more pages we want on the partial
+	 * The larger the object size is, the more slabs we want on the partial
 	 * list to avoid pounding the page allocator excessively.
 	 */
 	set_min_partial(s, ilog2(s->size) / 2);
@@ -4597,12 +4596,12 @@ static int __kmem_cache_do_shrink(struct kmem_cache *s)
 		 * Build lists of slabs to discard or promote.
 		 *
 		 * Note that concurrent frees may occur while we hold the
-		 * list_lock. page->inuse here is the upper limit.
+		 * list_lock. slab->inuse here is the upper limit.
 		 */
 		list_for_each_entry_safe(slab, t, &n->partial, slab_list) {
 			int free = slab->objects - slab->inuse;
 
-			/* Do not reread page->inuse */
+			/* Do not reread slab->inuse */
 			barrier();
 
 			/* We do not keep full slabs on the list */
@@ -5480,7 +5479,7 @@ static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
 			slabs += slab->slabs;
 	}
 
-	/* Approximate half-full pages , see slub_set_cpu_partial() */
+	/* Approximate half-full slabs, see slub_set_cpu_partial() */
 	objects = (slabs * oo_objects(s->oo)) / 2;
 	len += sysfs_emit_at(buf, len, "%d(%d)", objects, slabs);
 
-- 
2.33.1

[PATCH v2 19/33] mm/slab: Convert kmem_getpages() and kmem_freepages() to struct slab

[Vlastimil Babka]

These functions sit at the boundary to page allocator. Also use folio
internally to avoid extra compound_head() when dealing with page flags.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slab.c | 52 ++++++++++++++++++++++++++++------------------------
 1 file changed, 28 insertions(+), 24 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index 38fcd3f496df..892f7042b3b9 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1367,57 +1367,61 @@ slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid)
  * did not request dmaable memory, we might get it, but that
  * would be relatively rare and ignorable.
  */
-static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
+static struct slab *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
 								int nodeid)
 {
-	struct page *page;
+	struct folio *folio;
+	struct slab *slab;
 
 	flags |= cachep->allocflags;
 
-	page = __alloc_pages_node(nodeid, flags, cachep->gfporder);
-	if (!page) {
+	folio = (struct folio *) __alloc_pages_node(nodeid, flags, cachep->gfporder);
+	if (!folio) {
 		slab_out_of_memory(cachep, flags, nodeid);
 		return NULL;
 	}
 
-	account_slab(page_slab(page), cachep->gfporder, cachep, flags);
-	__SetPageSlab(page);
+	slab = folio_slab(folio);
+
+	account_slab(slab, cachep->gfporder, cachep, flags);
+	__folio_set_slab(folio);
 	/* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
-	if (sk_memalloc_socks() && page_is_pfmemalloc(page))
-		SetPageSlabPfmemalloc(page);
+	if (sk_memalloc_socks() && page_is_pfmemalloc(folio_page(folio, 0)))
+		slab_set_pfmemalloc(slab);
 
-	return page;
+	return slab;
 }
 
 /*
  * Interface to system's page release.
  */
-static void kmem_freepages(struct kmem_cache *cachep, struct page *page)
+static void kmem_freepages(struct kmem_cache *cachep, struct slab *slab)
 {
 	int order = cachep->gfporder;
+	struct folio *folio = slab_folio(slab);
 
-	BUG_ON(!PageSlab(page));
-	__ClearPageSlabPfmemalloc(page);
-	__ClearPageSlab(page);
-	page_mapcount_reset(page);
+	BUG_ON(!folio_test_slab(folio));
+	__slab_clear_pfmemalloc(slab);
+	__folio_clear_slab(folio);
+	page_mapcount_reset(folio_page(folio, 0));
 	/* In union with page->mapping where page allocator expects NULL */
-	page->slab_cache = NULL;
+	slab->slab_cache = NULL;
 
 	if (current->reclaim_state)
 		current->reclaim_state->reclaimed_slab += 1 << order;
-	unaccount_slab(page_slab(page), order, cachep);
-	__free_pages(page, order);
+	unaccount_slab(slab, order, cachep);
+	__free_pages(folio_page(folio, 0), order);
 }
 
 static void kmem_rcu_free(struct rcu_head *head)
 {
 	struct kmem_cache *cachep;
-	struct page *page;
+	struct slab *slab;
 
-	page = container_of(head, struct page, rcu_head);
-	cachep = page->slab_cache;
+	slab = container_of(head, struct slab, rcu_head);
+	cachep = slab->slab_cache;
 
-	kmem_freepages(cachep, page);
+	kmem_freepages(cachep, slab);
 }
 
 #if DEBUG
@@ -1624,7 +1628,7 @@ static void slab_destroy(struct kmem_cache *cachep, struct page *page)
 	if (unlikely(cachep->flags & SLAB_TYPESAFE_BY_RCU))
 		call_rcu(&page->rcu_head, kmem_rcu_free);
 	else
-		kmem_freepages(cachep, page);
+		kmem_freepages(cachep, page_slab(page));
 
 	/*
 	 * From now on, we don't use freelist
@@ -2578,7 +2582,7 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep,
 	 * Get mem for the objs.  Attempt to allocate a physical page from
 	 * 'nodeid'.
 	 */
-	page = kmem_getpages(cachep, local_flags, nodeid);
+	page = slab_page(kmem_getpages(cachep, local_flags, nodeid));
 	if (!page)
 		goto failed;
 
@@ -2620,7 +2624,7 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep,
 	return page;
 
 opps1:
-	kmem_freepages(cachep, page);
+	kmem_freepages(cachep, page_slab(page));
 failed:
 	if (gfpflags_allow_blocking(local_flags))
 		local_irq_disable();
-- 
2.33.1

[PATCH v2 20/33] mm/slab: Convert most struct page to struct slab by spatch

[Vlastimil Babka]

The majority of conversion from struct page to struct slab in SLAB internals
can be delegated to a coccinelle semantic patch. This includes renaming of
variables with 'page' in name to 'slab', and similar.

Big thanks to Julia Lawall and Luis Chamberlain for help with coccinelle.

// Options: --include-headers --no-includes --smpl-spacing mm/slab.c
// Note: needs coccinelle 1.1.1 to avoid breaking whitespace, and ocaml for the
// embedded script script

// build list of functions for applying the next rule
@initialize:ocaml@
@@

let ok_function p =
  not (List.mem (List.hd p).current_element ["kmem_getpages";"kmem_freepages"])

// convert the type in selected functions
@@
position p : script:ocaml() { ok_function p };
@@

- struct page@p
+ struct slab

@@
@@

-PageSlabPfmemalloc(page)
+slab_test_pfmemalloc(slab)

@@
@@

-ClearPageSlabPfmemalloc(page)
+slab_clear_pfmemalloc(slab)

@@
@@

obj_to_index(
 ...,
- page
+ slab_page(slab)
,...)

// for all functions, change any "struct slab *page" parameter to "struct slab
// *slab" in the signature, and generally all occurences of "page" to "slab" in
// the body - with some special cases.
@@
identifier fn;
expression E;
@@

 fn(...,
-   struct slab *page
+   struct slab *slab
    ,...)
 {
<...
(
- int page_node;
+ int slab_node;
|
- page_node
+ slab_node
|
- page_slab(page)
+ slab
|
- page_address(page)
+ slab_address(slab)
|
- page_size(page)
+ slab_size(slab)
|
- page_to_nid(page)
+ slab_nid(slab)
|
- virt_to_head_page(E)
+ virt_to_slab(E)
|
- page
+ slab
)
...>
 }

// rename a function parameter
@@
identifier fn;
expression E;
@@

 fn(...,
-   int page_node
+   int slab_node
    ,...)
 {
<...
- page_node
+ slab_node
...>
 }

// functions converted by previous rules that were temporarily called using
// slab_page(E) so we want to remove the wrapper now that they accept struct
// slab ptr directly
@@
identifier fn =~ "index_to_obj";
expression E;
@@

 fn(...,
- slab_page(E)
+ E
 ,...)

// functions that were returning struct page ptr and now will return struct
// slab ptr, including slab_page() wrapper removal
@@
identifier fn =~ "cache_grow_begin|get_valid_first_slab|get_first_slab";
expression E;
@@

 fn(...)
 {
<...
- slab_page(E)
+ E
...>
 }

// rename any former struct page * declarations
@@
@@

struct slab *
-page
+slab
;

// all functions (with exceptions) with a local "struct slab *page" variable
// that will be renamed to "struct slab *slab"
@@
identifier fn !~ "kmem_getpages|kmem_freepages";
expression E;
@@

 fn(...)
 {
<...
(
- page_slab(page)
+ slab
|
- page_to_nid(page)
+ slab_nid(slab)
|
- kasan_poison_slab(page)
+ kasan_poison_slab(slab_page(slab))
|
- page_address(page)
+ slab_address(slab)
|
- page_size(page)
+ slab_size(slab)
|
- page->pages
+ slab->slabs
|
- page = virt_to_head_page(E)
+ slab = virt_to_slab(E)
|
- virt_to_head_page(E)
+ virt_to_slab(E)
|
- page
+ slab
)
...>
 }

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Julia Lawall <julia.lawall@inria.fr>
Cc: Luis Chamberlain <mcgrof@kernel.org>
---
 mm/slab.c | 360 +++++++++++++++++++++++++++---------------------------
 1 file changed, 180 insertions(+), 180 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index 892f7042b3b9..970b3e13b4c1 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -218,7 +218,7 @@ static void cache_reap(struct work_struct *unused);
 static inline void fixup_objfreelist_debug(struct kmem_cache *cachep,
 						void **list);
 static inline void fixup_slab_list(struct kmem_cache *cachep,
-				struct kmem_cache_node *n, struct page *page,
+				struct kmem_cache_node *n, struct slab *slab,
 				void **list);
 static int slab_early_init = 1;
 
@@ -373,9 +373,9 @@ static int slab_max_order = SLAB_MAX_ORDER_LO;
 static bool slab_max_order_set __initdata;
 
 static inline void *index_to_obj(struct kmem_cache *cache,
-				 const struct page *page, unsigned int idx)
+				 const struct slab *slab, unsigned int idx)
 {
-	return page->s_mem + cache->size * idx;
+	return slab->s_mem + cache->size * idx;
 }
 
 #define BOOT_CPUCACHE_ENTRIES	1
@@ -550,17 +550,17 @@ static struct array_cache *alloc_arraycache(int node, int entries,
 }
 
 static noinline void cache_free_pfmemalloc(struct kmem_cache *cachep,
-					struct page *page, void *objp)
+					struct slab *slab, void *objp)
 {
 	struct kmem_cache_node *n;
-	int page_node;
+	int slab_node;
 	LIST_HEAD(list);
 
-	page_node = page_to_nid(page);
-	n = get_node(cachep, page_node);
+	slab_node = slab_nid(slab);
+	n = get_node(cachep, slab_node);
 
 	spin_lock(&n->list_lock);
-	free_block(cachep, &objp, 1, page_node, &list);
+	free_block(cachep, &objp, 1, slab_node, &list);
 	spin_unlock(&n->list_lock);
 
 	slabs_destroy(cachep, &list);
@@ -761,7 +761,7 @@ static void drain_alien_cache(struct kmem_cache *cachep,
 }
 
 static int __cache_free_alien(struct kmem_cache *cachep, void *objp,
-				int node, int page_node)
+				int node, int slab_node)
 {
 	struct kmem_cache_node *n;
 	struct alien_cache *alien = NULL;
@@ -770,21 +770,21 @@ static int __cache_free_alien(struct kmem_cache *cachep, void *objp,
 
 	n = get_node(cachep, node);
 	STATS_INC_NODEFREES(cachep);
-	if (n->alien && n->alien[page_node]) {
-		alien = n->alien[page_node];
+	if (n->alien && n->alien[slab_node]) {
+		alien = n->alien[slab_node];
 		ac = &alien->ac;
 		spin_lock(&alien->lock);
 		if (unlikely(ac->avail == ac->limit)) {
 			STATS_INC_ACOVERFLOW(cachep);
-			__drain_alien_cache(cachep, ac, page_node, &list);
+			__drain_alien_cache(cachep, ac, slab_node, &list);
 		}
 		__free_one(ac, objp);
 		spin_unlock(&alien->lock);
 		slabs_destroy(cachep, &list);
 	} else {
-		n = get_node(cachep, page_node);
+		n = get_node(cachep, slab_node);
 		spin_lock(&n->list_lock);
-		free_block(cachep, &objp, 1, page_node, &list);
+		free_block(cachep, &objp, 1, slab_node, &list);
 		spin_unlock(&n->list_lock);
 		slabs_destroy(cachep, &list);
 	}
@@ -1557,18 +1557,18 @@ static void check_poison_obj(struct kmem_cache *cachep, void *objp)
 		/* Print some data about the neighboring objects, if they
 		 * exist:
 		 */
-		struct page *page = virt_to_head_page(objp);
+		struct slab *slab = virt_to_slab(objp);
 		unsigned int objnr;
 
-		objnr = obj_to_index(cachep, page, objp);
+		objnr = obj_to_index(cachep, slab_page(slab), objp);
 		if (objnr) {
-			objp = index_to_obj(cachep, page, objnr - 1);
+			objp = index_to_obj(cachep, slab, objnr - 1);
 			realobj = (char *)objp + obj_offset(cachep);
 			pr_err("Prev obj: start=%px, len=%d\n", realobj, size);
 			print_objinfo(cachep, objp, 2);
 		}
 		if (objnr + 1 < cachep->num) {
-			objp = index_to_obj(cachep, page, objnr + 1);
+			objp = index_to_obj(cachep, slab, objnr + 1);
 			realobj = (char *)objp + obj_offset(cachep);
 			pr_err("Next obj: start=%px, len=%d\n", realobj, size);
 			print_objinfo(cachep, objp, 2);
@@ -1579,17 +1579,17 @@ static void check_poison_obj(struct kmem_cache *cachep, void *objp)
 
 #if DEBUG
 static void slab_destroy_debugcheck(struct kmem_cache *cachep,
-						struct page *page)
+						struct slab *slab)
 {
 	int i;
 
 	if (OBJFREELIST_SLAB(cachep) && cachep->flags & SLAB_POISON) {
-		poison_obj(cachep, page->freelist - obj_offset(cachep),
+		poison_obj(cachep, slab->freelist - obj_offset(cachep),
 			POISON_FREE);
 	}
 
 	for (i = 0; i < cachep->num; i++) {
-		void *objp = index_to_obj(cachep, page, i);
+		void *objp = index_to_obj(cachep, slab, i);
 
 		if (cachep->flags & SLAB_POISON) {
 			check_poison_obj(cachep, objp);
@@ -1605,7 +1605,7 @@ static void slab_destroy_debugcheck(struct kmem_cache *cachep,
 }
 #else
 static void slab_destroy_debugcheck(struct kmem_cache *cachep,
-						struct page *page)
+						struct slab *slab)
 {
 }
 #endif
@@ -1619,16 +1619,16 @@ static void slab_destroy_debugcheck(struct kmem_cache *cachep,
  * Before calling the slab page must have been unlinked from the cache. The
  * kmem_cache_node ->list_lock is not held/needed.
  */
-static void slab_destroy(struct kmem_cache *cachep, struct page *page)
+static void slab_destroy(struct kmem_cache *cachep, struct slab *slab)
 {
 	void *freelist;
 
-	freelist = page->freelist;
-	slab_destroy_debugcheck(cachep, page);
+	freelist = slab->freelist;
+	slab_destroy_debugcheck(cachep, slab);
 	if (unlikely(cachep->flags & SLAB_TYPESAFE_BY_RCU))
-		call_rcu(&page->rcu_head, kmem_rcu_free);
+		call_rcu(&slab->rcu_head, kmem_rcu_free);
 	else
-		kmem_freepages(cachep, page_slab(page));
+		kmem_freepages(cachep, slab);
 
 	/*
 	 * From now on, we don't use freelist
@@ -1644,11 +1644,11 @@ static void slab_destroy(struct kmem_cache *cachep, struct page *page)
  */
 static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list)
 {
-	struct page *page, *n;
+	struct slab *slab, *n;
 
-	list_for_each_entry_safe(page, n, list, slab_list) {
-		list_del(&page->slab_list);
-		slab_destroy(cachep, page);
+	list_for_each_entry_safe(slab, n, list, slab_list) {
+		list_del(&slab->slab_list);
+		slab_destroy(cachep, slab);
 	}
 }
 
@@ -2198,7 +2198,7 @@ static int drain_freelist(struct kmem_cache *cache,
 {
 	struct list_head *p;
 	int nr_freed;
-	struct page *page;
+	struct slab *slab;
 
 	nr_freed = 0;
 	while (nr_freed < tofree && !list_empty(&n->slabs_free)) {
@@ -2210,8 +2210,8 @@ static int drain_freelist(struct kmem_cache *cache,
 			goto out;
 		}
 
-		page = list_entry(p, struct page, slab_list);
-		list_del(&page->slab_list);
+		slab = list_entry(p, struct slab, slab_list);
+		list_del(&slab->slab_list);
 		n->free_slabs--;
 		n->total_slabs--;
 		/*
@@ -2220,7 +2220,7 @@ static int drain_freelist(struct kmem_cache *cache,
 		 */
 		n->free_objects -= cache->num;
 		spin_unlock_irq(&n->list_lock);
-		slab_destroy(cache, page);
+		slab_destroy(cache, slab);
 		nr_freed++;
 	}
 out:
@@ -2295,14 +2295,14 @@ void __kmem_cache_release(struct kmem_cache *cachep)
  * which are all initialized during kmem_cache_init().
  */
 static void *alloc_slabmgmt(struct kmem_cache *cachep,
-				   struct page *page, int colour_off,
+				   struct slab *slab, int colour_off,
 				   gfp_t local_flags, int nodeid)
 {
 	void *freelist;
-	void *addr = page_address(page);
+	void *addr = slab_address(slab);
 
-	page->s_mem = addr + colour_off;
-	page->active = 0;
+	slab->s_mem = addr + colour_off;
+	slab->active = 0;
 
 	if (OBJFREELIST_SLAB(cachep))
 		freelist = NULL;
@@ -2319,24 +2319,24 @@ static void *alloc_slabmgmt(struct kmem_cache *cachep,
 	return freelist;
 }
 
-static inline freelist_idx_t get_free_obj(struct page *page, unsigned int idx)
+static inline freelist_idx_t get_free_obj(struct slab *slab, unsigned int idx)
 {
-	return ((freelist_idx_t *)page->freelist)[idx];
+	return ((freelist_idx_t *) slab->freelist)[idx];
 }
 
-static inline void set_free_obj(struct page *page,
+static inline void set_free_obj(struct slab *slab,
 					unsigned int idx, freelist_idx_t val)
 {
-	((freelist_idx_t *)(page->freelist))[idx] = val;
+	((freelist_idx_t *)(slab->freelist))[idx] = val;
 }
 
-static void cache_init_objs_debug(struct kmem_cache *cachep, struct page *page)
+static void cache_init_objs_debug(struct kmem_cache *cachep, struct slab *slab)
 {
 #if DEBUG
 	int i;
 
 	for (i = 0; i < cachep->num; i++) {
-		void *objp = index_to_obj(cachep, page, i);
+		void *objp = index_to_obj(cachep, slab, i);
 
 		if (cachep->flags & SLAB_STORE_USER)
 			*dbg_userword(cachep, objp) = NULL;
@@ -2420,17 +2420,17 @@ static freelist_idx_t next_random_slot(union freelist_init_state *state)
 }
 
 /* Swap two freelist entries */
-static void swap_free_obj(struct page *page, unsigned int a, unsigned int b)
+static void swap_free_obj(struct slab *slab, unsigned int a, unsigned int b)
 {
-	swap(((freelist_idx_t *)page->freelist)[a],
-		((freelist_idx_t *)page->freelist)[b]);
+	swap(((freelist_idx_t *) slab->freelist)[a],
+		((freelist_idx_t *) slab->freelist)[b]);
 }
 
 /*
  * Shuffle the freelist initialization state based on pre-computed lists.
  * return true if the list was successfully shuffled, false otherwise.
  */
-static bool shuffle_freelist(struct kmem_cache *cachep, struct page *page)
+static bool shuffle_freelist(struct kmem_cache *cachep, struct slab *slab)
 {
 	unsigned int objfreelist = 0, i, rand, count = cachep->num;
 	union freelist_init_state state;
@@ -2447,7 +2447,7 @@ static bool shuffle_freelist(struct kmem_cache *cachep, struct page *page)
 			objfreelist = count - 1;
 		else
 			objfreelist = next_random_slot(&state);
-		page->freelist = index_to_obj(cachep, page, objfreelist) +
+		slab->freelist = index_to_obj(cachep, slab, objfreelist) +
 						obj_offset(cachep);
 		count--;
 	}
@@ -2458,51 +2458,51 @@ static bool shuffle_freelist(struct kmem_cache *cachep, struct page *page)
 	 */
 	if (!precomputed) {
 		for (i = 0; i < count; i++)
-			set_free_obj(page, i, i);
+			set_free_obj(slab, i, i);
 
 		/* Fisher-Yates shuffle */
 		for (i = count - 1; i > 0; i--) {
 			rand = prandom_u32_state(&state.rnd_state);
 			rand %= (i + 1);
-			swap_free_obj(page, i, rand);
+			swap_free_obj(slab, i, rand);
 		}
 	} else {
 		for (i = 0; i < count; i++)
-			set_free_obj(page, i, next_random_slot(&state));
+			set_free_obj(slab, i, next_random_slot(&state));
 	}
 
 	if (OBJFREELIST_SLAB(cachep))
-		set_free_obj(page, cachep->num - 1, objfreelist);
+		set_free_obj(slab, cachep->num - 1, objfreelist);
 
 	return true;
 }
 #else
 static inline bool shuffle_freelist(struct kmem_cache *cachep,
-				struct page *page)
+				struct slab *slab)
 {
 	return false;
 }
 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
 
 static void cache_init_objs(struct kmem_cache *cachep,
-			    struct page *page)
+			    struct slab *slab)
 {
 	int i;
 	void *objp;
 	bool shuffled;
 
-	cache_init_objs_debug(cachep, page);
+	cache_init_objs_debug(cachep, slab);
 
 	/* Try to randomize the freelist if enabled */
-	shuffled = shuffle_freelist(cachep, page);
+	shuffled = shuffle_freelist(cachep, slab);
 
 	if (!shuffled && OBJFREELIST_SLAB(cachep)) {
-		page->freelist = index_to_obj(cachep, page, cachep->num - 1) +
+		slab->freelist = index_to_obj(cachep, slab, cachep->num - 1) +
 						obj_offset(cachep);
 	}
 
 	for (i = 0; i < cachep->num; i++) {
-		objp = index_to_obj(cachep, page, i);
+		objp = index_to_obj(cachep, slab, i);
 		objp = kasan_init_slab_obj(cachep, objp);
 
 		/* constructor could break poison info */
@@ -2513,48 +2513,48 @@ static void cache_init_objs(struct kmem_cache *cachep,
 		}
 
 		if (!shuffled)
-			set_free_obj(page, i, i);
+			set_free_obj(slab, i, i);
 	}
 }
 
-static void *slab_get_obj(struct kmem_cache *cachep, struct page *page)
+static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slab)
 {
 	void *objp;
 
-	objp = index_to_obj(cachep, page, get_free_obj(page, page->active));
-	page->active++;
+	objp = index_to_obj(cachep, slab, get_free_obj(slab, slab->active));
+	slab->active++;
 
 	return objp;
 }
 
 static void slab_put_obj(struct kmem_cache *cachep,
-			struct page *page, void *objp)
+			struct slab *slab, void *objp)
 {
-	unsigned int objnr = obj_to_index(cachep, page, objp);
+	unsigned int objnr = obj_to_index(cachep, slab_page(slab), objp);
 #if DEBUG
 	unsigned int i;
 
 	/* Verify double free bug */
-	for (i = page->active; i < cachep->num; i++) {
-		if (get_free_obj(page, i) == objnr) {
+	for (i = slab->active; i < cachep->num; i++) {
+		if (get_free_obj(slab, i) == objnr) {
 			pr_err("slab: double free detected in cache '%s', objp %px\n",
 			       cachep->name, objp);
 			BUG();
 		}
 	}
 #endif
-	page->active--;
-	if (!page->freelist)
-		page->freelist = objp + obj_offset(cachep);
+	slab->active--;
+	if (!slab->freelist)
+		slab->freelist = objp + obj_offset(cachep);
 
-	set_free_obj(page, page->active, objnr);
+	set_free_obj(slab, slab->active, objnr);
 }
 
 /*
  * Grow (by 1) the number of slabs within a cache.  This is called by
  * kmem_cache_alloc() when there are no active objs left in a cache.
  */
-static struct page *cache_grow_begin(struct kmem_cache *cachep,
+static struct slab *cache_grow_begin(struct kmem_cache *cachep,
 				gfp_t flags, int nodeid)
 {
 	void *freelist;
@@ -2562,7 +2562,7 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep,
 	gfp_t local_flags;
 	int page_node;
 	struct kmem_cache_node *n;
-	struct page *page;
+	struct slab *slab;
 
 	/*
 	 * Be lazy and only check for valid flags here,  keeping it out of the
@@ -2582,11 +2582,11 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep,
 	 * Get mem for the objs.  Attempt to allocate a physical page from
 	 * 'nodeid'.
 	 */
-	page = slab_page(kmem_getpages(cachep, local_flags, nodeid));
-	if (!page)
+	slab = kmem_getpages(cachep, local_flags, nodeid);
+	if (!slab)
 		goto failed;
 
-	page_node = page_to_nid(page);
+	page_node = slab_nid(slab);
 	n = get_node(cachep, page_node);
 
 	/* Get colour for the slab, and cal the next value. */
@@ -2605,55 +2605,55 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep,
 	 * page_address() in the latter returns a non-tagged pointer,
 	 * as it should be for slab pages.
 	 */
-	kasan_poison_slab(page);
+	kasan_poison_slab(slab_page(slab));
 
 	/* Get slab management. */
-	freelist = alloc_slabmgmt(cachep, page, offset,
+	freelist = alloc_slabmgmt(cachep, slab, offset,
 			local_flags & ~GFP_CONSTRAINT_MASK, page_node);
 	if (OFF_SLAB(cachep) && !freelist)
 		goto opps1;
 
-	page->slab_cache = cachep;
-	page->freelist = freelist;
+	slab->slab_cache = cachep;
+	slab->freelist = freelist;
 
-	cache_init_objs(cachep, page);
+	cache_init_objs(cachep, slab);
 
 	if (gfpflags_allow_blocking(local_flags))
 		local_irq_disable();
 
-	return page;
+	return slab;
 
 opps1:
-	kmem_freepages(cachep, page_slab(page));
+	kmem_freepages(cachep, slab);
 failed:
 	if (gfpflags_allow_blocking(local_flags))
 		local_irq_disable();
 	return NULL;
 }
 
-static void cache_grow_end(struct kmem_cache *cachep, struct page *page)
+static void cache_grow_end(struct kmem_cache *cachep, struct slab *slab)
 {
 	struct kmem_cache_node *n;
 	void *list = NULL;
 
 	check_irq_off();
 
-	if (!page)
+	if (!slab)
 		return;
 
-	INIT_LIST_HEAD(&page->slab_list);
-	n = get_node(cachep, page_to_nid(page));
+	INIT_LIST_HEAD(&slab->slab_list);
+	n = get_node(cachep, slab_nid(slab));
 
 	spin_lock(&n->list_lock);
 	n->total_slabs++;
-	if (!page->active) {
-		list_add_tail(&page->slab_list, &n->slabs_free);
+	if (!slab->active) {
+		list_add_tail(&slab->slab_list, &n->slabs_free);
 		n->free_slabs++;
 	} else
-		fixup_slab_list(cachep, n, page, &list);
+		fixup_slab_list(cachep, n, slab, &list);
 
 	STATS_INC_GROWN(cachep);
-	n->free_objects += cachep->num - page->active;
+	n->free_objects += cachep->num - slab->active;
 	spin_unlock(&n->list_lock);
 
 	fixup_objfreelist_debug(cachep, &list);
@@ -2701,13 +2701,13 @@ static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
 				   unsigned long caller)
 {
 	unsigned int objnr;
-	struct page *page;
+	struct slab *slab;
 
 	BUG_ON(virt_to_cache(objp) != cachep);
 
 	objp -= obj_offset(cachep);
 	kfree_debugcheck(objp);
-	page = virt_to_head_page(objp);
+	slab = virt_to_slab(objp);
 
 	if (cachep->flags & SLAB_RED_ZONE) {
 		verify_redzone_free(cachep, objp);
@@ -2717,10 +2717,10 @@ static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
 	if (cachep->flags & SLAB_STORE_USER)
 		*dbg_userword(cachep, objp) = (void *)caller;
 
-	objnr = obj_to_index(cachep, page, objp);
+	objnr = obj_to_index(cachep, slab_page(slab), objp);
 
 	BUG_ON(objnr >= cachep->num);
-	BUG_ON(objp != index_to_obj(cachep, page, objnr));
+	BUG_ON(objp != index_to_obj(cachep, slab, objnr));
 
 	if (cachep->flags & SLAB_POISON) {
 		poison_obj(cachep, objp, POISON_FREE);
@@ -2750,97 +2750,97 @@ static inline void fixup_objfreelist_debug(struct kmem_cache *cachep,
 }
 
 static inline void fixup_slab_list(struct kmem_cache *cachep,
-				struct kmem_cache_node *n, struct page *page,
+				struct kmem_cache_node *n, struct slab *slab,
 				void **list)
 {
 	/* move slabp to correct slabp list: */
-	list_del(&page->slab_list);
-	if (page->active == cachep->num) {
-		list_add(&page->slab_list, &n->slabs_full);
+	list_del(&slab->slab_list);
+	if (slab->active == cachep->num) {
+		list_add(&slab->slab_list, &n->slabs_full);
 		if (OBJFREELIST_SLAB(cachep)) {
 #if DEBUG
 			/* Poisoning will be done without holding the lock */
 			if (cachep->flags & SLAB_POISON) {
-				void **objp = page->freelist;
+				void **objp = slab->freelist;
 
 				*objp = *list;
 				*list = objp;
 			}
 #endif
-			page->freelist = NULL;
+			slab->freelist = NULL;
 		}
 	} else
-		list_add(&page->slab_list, &n->slabs_partial);
+		list_add(&slab->slab_list, &n->slabs_partial);
 }
 
 /* Try to find non-pfmemalloc slab if needed */
-static noinline struct page *get_valid_first_slab(struct kmem_cache_node *n,
-					struct page *page, bool pfmemalloc)
+static noinline struct slab *get_valid_first_slab(struct kmem_cache_node *n,
+					struct slab *slab, bool pfmemalloc)
 {
-	if (!page)
+	if (!slab)
 		return NULL;
 
 	if (pfmemalloc)
-		return page;
+		return slab;
 
-	if (!PageSlabPfmemalloc(page))
-		return page;
+	if (!slab_test_pfmemalloc(slab))
+		return slab;
 
 	/* No need to keep pfmemalloc slab if we have enough free objects */
 	if (n->free_objects > n->free_limit) {
-		ClearPageSlabPfmemalloc(page);
-		return page;
+		slab_clear_pfmemalloc(slab);
+		return slab;
 	}
 
 	/* Move pfmemalloc slab to the end of list to speed up next search */
-	list_del(&page->slab_list);
-	if (!page->active) {
-		list_add_tail(&page->slab_list, &n->slabs_free);
+	list_del(&slab->slab_list);
+	if (!slab->active) {
+		list_add_tail(&slab->slab_list, &n->slabs_free);
 		n->free_slabs++;
 	} else
-		list_add_tail(&page->slab_list, &n->slabs_partial);
+		list_add_tail(&slab->slab_list, &n->slabs_partial);
 
-	list_for_each_entry(page, &n->slabs_partial, slab_list) {
-		if (!PageSlabPfmemalloc(page))
-			return page;
+	list_for_each_entry(slab, &n->slabs_partial, slab_list) {
+		if (!slab_test_pfmemalloc(slab))
+			return slab;
 	}
 
 	n->free_touched = 1;
-	list_for_each_entry(page, &n->slabs_free, slab_list) {
-		if (!PageSlabPfmemalloc(page)) {
+	list_for_each_entry(slab, &n->slabs_free, slab_list) {
+		if (!slab_test_pfmemalloc(slab)) {
 			n->free_slabs--;
-			return page;
+			return slab;
 		}
 	}
 
 	return NULL;
 }
 
-static struct page *get_first_slab(struct kmem_cache_node *n, bool pfmemalloc)
+static struct slab *get_first_slab(struct kmem_cache_node *n, bool pfmemalloc)
 {
-	struct page *page;
+	struct slab *slab;
 
 	assert_spin_locked(&n->list_lock);
-	page = list_first_entry_or_null(&n->slabs_partial, struct page,
+	slab = list_first_entry_or_null(&n->slabs_partial, struct slab,
 					slab_list);
-	if (!page) {
+	if (!slab) {
 		n->free_touched = 1;
-		page = list_first_entry_or_null(&n->slabs_free, struct page,
+		slab = list_first_entry_or_null(&n->slabs_free, struct slab,
 						slab_list);
-		if (page)
+		if (slab)
 			n->free_slabs--;
 	}
 
 	if (sk_memalloc_socks())
-		page = get_valid_first_slab(n, page, pfmemalloc);
+		slab = get_valid_first_slab(n, slab, pfmemalloc);
 
-	return page;
+	return slab;
 }
 
 static noinline void *cache_alloc_pfmemalloc(struct kmem_cache *cachep,
 				struct kmem_cache_node *n, gfp_t flags)
 {
-	struct page *page;
+	struct slab *slab;
 	void *obj;
 	void *list = NULL;
 
@@ -2848,16 +2848,16 @@ static noinline void *cache_alloc_pfmemalloc(struct kmem_cache *cachep,
 		return NULL;
 
 	spin_lock(&n->list_lock);
-	page = get_first_slab(n, true);
-	if (!page) {
+	slab = get_first_slab(n, true);
+	if (!slab) {
 		spin_unlock(&n->list_lock);
 		return NULL;
 	}
 
-	obj = slab_get_obj(cachep, page);
+	obj = slab_get_obj(cachep, slab);
 	n->free_objects--;
 
-	fixup_slab_list(cachep, n, page, &list);
+	fixup_slab_list(cachep, n, slab, &list);
 
 	spin_unlock(&n->list_lock);
 	fixup_objfreelist_debug(cachep, &list);
@@ -2870,20 +2870,20 @@ static noinline void *cache_alloc_pfmemalloc(struct kmem_cache *cachep,
  * or cache_grow_end() for new slab
  */
 static __always_inline int alloc_block(struct kmem_cache *cachep,
-		struct array_cache *ac, struct page *page, int batchcount)
+		struct array_cache *ac, struct slab *slab, int batchcount)
 {
 	/*
 	 * There must be at least one object available for
 	 * allocation.
 	 */
-	BUG_ON(page->active >= cachep->num);
+	BUG_ON(slab->active >= cachep->num);
 
-	while (page->active < cachep->num && batchcount--) {
+	while (slab->active < cachep->num && batchcount--) {
 		STATS_INC_ALLOCED(cachep);
 		STATS_INC_ACTIVE(cachep);
 		STATS_SET_HIGH(cachep);
 
-		ac->entry[ac->avail++] = slab_get_obj(cachep, page);
+		ac->entry[ac->avail++] = slab_get_obj(cachep, slab);
 	}
 
 	return batchcount;
@@ -2896,7 +2896,7 @@ static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
 	struct array_cache *ac, *shared;
 	int node;
 	void *list = NULL;
-	struct page *page;
+	struct slab *slab;
 
 	check_irq_off();
 	node = numa_mem_id();
@@ -2929,14 +2929,14 @@ static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
 
 	while (batchcount > 0) {
 		/* Get slab alloc is to come from. */
-		page = get_first_slab(n, false);
-		if (!page)
+		slab = get_first_slab(n, false);
+		if (!slab)
 			goto must_grow;
 
 		check_spinlock_acquired(cachep);
 
-		batchcount = alloc_block(cachep, ac, page, batchcount);
-		fixup_slab_list(cachep, n, page, &list);
+		batchcount = alloc_block(cachep, ac, slab, batchcount);
+		fixup_slab_list(cachep, n, slab, &list);
 	}
 
 must_grow:
@@ -2955,16 +2955,16 @@ static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
 				return obj;
 		}
 
-		page = cache_grow_begin(cachep, gfp_exact_node(flags), node);
+		slab = cache_grow_begin(cachep, gfp_exact_node(flags), node);
 
 		/*
 		 * cache_grow_begin() can reenable interrupts,
 		 * then ac could change.
 		 */
 		ac = cpu_cache_get(cachep);
-		if (!ac->avail && page)
-			alloc_block(cachep, ac, page, batchcount);
-		cache_grow_end(cachep, page);
+		if (!ac->avail && slab)
+			alloc_block(cachep, ac, slab, batchcount);
+		cache_grow_end(cachep, slab);
 
 		if (!ac->avail)
 			return NULL;
@@ -3094,7 +3094,7 @@ static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
 	struct zone *zone;
 	enum zone_type highest_zoneidx = gfp_zone(flags);
 	void *obj = NULL;
-	struct page *page;
+	struct slab *slab;
 	int nid;
 	unsigned int cpuset_mems_cookie;
 
@@ -3130,10 +3130,10 @@ static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
 		 * We may trigger various forms of reclaim on the allowed
 		 * set and go into memory reserves if necessary.
 		 */
-		page = cache_grow_begin(cache, flags, numa_mem_id());
-		cache_grow_end(cache, page);
-		if (page) {
-			nid = page_to_nid(page);
+		slab = cache_grow_begin(cache, flags, numa_mem_id());
+		cache_grow_end(cache, slab);
+		if (slab) {
+			nid = slab_nid(slab);
 			obj = ____cache_alloc_node(cache,
 				gfp_exact_node(flags), nid);
 
@@ -3157,7 +3157,7 @@ static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
 static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
 				int nodeid)
 {
-	struct page *page;
+	struct slab *slab;
 	struct kmem_cache_node *n;
 	void *obj = NULL;
 	void *list = NULL;
@@ -3168,8 +3168,8 @@ static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
 
 	check_irq_off();
 	spin_lock(&n->list_lock);
-	page = get_first_slab(n, false);
-	if (!page)
+	slab = get_first_slab(n, false);
+	if (!slab)
 		goto must_grow;
 
 	check_spinlock_acquired_node(cachep, nodeid);
@@ -3178,12 +3178,12 @@ static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
 	STATS_INC_ACTIVE(cachep);
 	STATS_SET_HIGH(cachep);
 
-	BUG_ON(page->active == cachep->num);
+	BUG_ON(slab->active == cachep->num);
 
-	obj = slab_get_obj(cachep, page);
+	obj = slab_get_obj(cachep, slab);
 	n->free_objects--;
 
-	fixup_slab_list(cachep, n, page, &list);
+	fixup_slab_list(cachep, n, slab, &list);
 
 	spin_unlock(&n->list_lock);
 	fixup_objfreelist_debug(cachep, &list);
@@ -3191,12 +3191,12 @@ static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
 
 must_grow:
 	spin_unlock(&n->list_lock);
-	page = cache_grow_begin(cachep, gfp_exact_node(flags), nodeid);
-	if (page) {
+	slab = cache_grow_begin(cachep, gfp_exact_node(flags), nodeid);
+	if (slab) {
 		/* This slab isn't counted yet so don't update free_objects */
-		obj = slab_get_obj(cachep, page);
+		obj = slab_get_obj(cachep, slab);
 	}
-	cache_grow_end(cachep, page);
+	cache_grow_end(cachep, slab);
 
 	return obj ? obj : fallback_alloc(cachep, flags);
 }
@@ -3326,40 +3326,40 @@ static void free_block(struct kmem_cache *cachep, void **objpp,
 {
 	int i;
 	struct kmem_cache_node *n = get_node(cachep, node);
-	struct page *page;
+	struct slab *slab;
 
 	n->free_objects += nr_objects;
 
 	for (i = 0; i < nr_objects; i++) {
 		void *objp;
-		struct page *page;
+		struct slab *slab;
 
 		objp = objpp[i];
 
-		page = virt_to_head_page(objp);
-		list_del(&page->slab_list);
+		slab = virt_to_slab(objp);
+		list_del(&slab->slab_list);
 		check_spinlock_acquired_node(cachep, node);
-		slab_put_obj(cachep, page, objp);
+		slab_put_obj(cachep, slab, objp);
 		STATS_DEC_ACTIVE(cachep);
 
 		/* fixup slab chains */
-		if (page->active == 0) {
-			list_add(&page->slab_list, &n->slabs_free);
+		if (slab->active == 0) {
+			list_add(&slab->slab_list, &n->slabs_free);
 			n->free_slabs++;
 		} else {
 			/* Unconditionally move a slab to the end of the
 			 * partial list on free - maximum time for the
 			 * other objects to be freed, too.
 			 */
-			list_add_tail(&page->slab_list, &n->slabs_partial);
+			list_add_tail(&slab->slab_list, &n->slabs_partial);
 		}
 	}
 
 	while (n->free_objects > n->free_limit && !list_empty(&n->slabs_free)) {
 		n->free_objects -= cachep->num;
 
-		page = list_last_entry(&n->slabs_free, struct page, slab_list);
-		list_move(&page->slab_list, list);
+		slab = list_last_entry(&n->slabs_free, struct slab, slab_list);
+		list_move(&slab->slab_list, list);
 		n->free_slabs--;
 		n->total_slabs--;
 	}
@@ -3395,10 +3395,10 @@ static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
 #if STATS
 	{
 		int i = 0;
-		struct page *page;
+		struct slab *slab;
 
-		list_for_each_entry(page, &n->slabs_free, slab_list) {
-			BUG_ON(page->active);
+		list_for_each_entry(slab, &n->slabs_free, slab_list) {
+			BUG_ON(slab->active);
 
 			i++;
 		}
@@ -3474,10 +3474,10 @@ void ___cache_free(struct kmem_cache *cachep, void *objp,
 	}
 
 	if (sk_memalloc_socks()) {
-		struct page *page = virt_to_head_page(objp);
+		struct slab *slab = virt_to_slab(objp);
 
-		if (unlikely(PageSlabPfmemalloc(page))) {
-			cache_free_pfmemalloc(cachep, page, objp);
+		if (unlikely(slab_test_pfmemalloc(slab))) {
+			cache_free_pfmemalloc(cachep, slab, objp);
 			return;
 		}
 	}
@@ -3664,7 +3664,7 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
 	kpp->kp_data_offset = obj_offset(cachep);
 	slab = virt_to_slab(objp);
 	objnr = obj_to_index(cachep, slab_page(slab), objp);
-	objp = index_to_obj(cachep, slab_page(slab), objnr);
+	objp = index_to_obj(cachep, slab, objnr);
 	kpp->kp_objp = objp;
 	if (DEBUG && cachep->flags & SLAB_STORE_USER)
 		kpp->kp_ret = *dbg_userword(cachep, objp);
@@ -4188,7 +4188,7 @@ void __check_heap_object(const void *ptr, unsigned long n,
 	if (is_kfence_address(ptr))
 		offset = ptr - kfence_object_start(ptr);
 	else
-		offset = ptr - index_to_obj(cachep, slab_page(slab), objnr) - obj_offset(cachep);
+		offset = ptr - index_to_obj(cachep, slab, objnr) - obj_offset(cachep);
 
 	/* Allow address range falling entirely within usercopy region. */
 	if (offset >= cachep->useroffset &&
-- 
2.33.1

[PATCH v2 21/33] mm/slab: Finish struct page to struct slab conversion

[Vlastimil Babka]

Change cache_free_alien() to use slab_nid(virt_to_slab()). Otherwise just
update of comments and some remaining variable names.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slab.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index 970b3e13b4c1..f0447b087d02 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -793,16 +793,16 @@ static int __cache_free_alien(struct kmem_cache *cachep, void *objp,
 
 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
 {
-	int page_node = page_to_nid(virt_to_page(objp));
+	int slab_node = slab_nid(virt_to_slab(objp));
 	int node = numa_mem_id();
 	/*
 	 * Make sure we are not freeing a object from another node to the array
 	 * cache on this cpu.
 	 */
-	if (likely(node == page_node))
+	if (likely(node == slab_node))
 		return 0;
 
-	return __cache_free_alien(cachep, objp, node, page_node);
+	return __cache_free_alien(cachep, objp, node, slab_node);
 }
 
 /*
@@ -1613,10 +1613,10 @@ static void slab_destroy_debugcheck(struct kmem_cache *cachep,
 /**
  * slab_destroy - destroy and release all objects in a slab
  * @cachep: cache pointer being destroyed
- * @page: page pointer being destroyed
+ * @slab: slab being destroyed
  *
- * Destroy all the objs in a slab page, and release the mem back to the system.
- * Before calling the slab page must have been unlinked from the cache. The
+ * Destroy all the objs in a slab, and release the mem back to the system.
+ * Before calling the slab must have been unlinked from the cache. The
  * kmem_cache_node ->list_lock is not held/needed.
  */
 static void slab_destroy(struct kmem_cache *cachep, struct slab *slab)
@@ -2560,7 +2560,7 @@ static struct slab *cache_grow_begin(struct kmem_cache *cachep,
 	void *freelist;
 	size_t offset;
 	gfp_t local_flags;
-	int page_node;
+	int slab_node;
 	struct kmem_cache_node *n;
 	struct slab *slab;
 
@@ -2586,8 +2586,8 @@ static struct slab *cache_grow_begin(struct kmem_cache *cachep,
 	if (!slab)
 		goto failed;
 
-	page_node = slab_nid(slab);
-	n = get_node(cachep, page_node);
+	slab_node = slab_nid(slab);
+	n = get_node(cachep, slab_node);
 
 	/* Get colour for the slab, and cal the next value. */
 	n->colour_next++;
@@ -2609,7 +2609,7 @@ static struct slab *cache_grow_begin(struct kmem_cache *cachep,
 
 	/* Get slab management. */
 	freelist = alloc_slabmgmt(cachep, slab, offset,
-			local_flags & ~GFP_CONSTRAINT_MASK, page_node);
+			local_flags & ~GFP_CONSTRAINT_MASK, slab_node);
 	if (OFF_SLAB(cachep) && !freelist)
 		goto opps1;
 
-- 
2.33.1

[PATCH v2 22/33] mm: Convert struct page to struct slab in functions used by other subsystems

[Vlastimil Babka]

KASAN, KFENCE and memcg interact with SLAB or SLUB internals through functions
nearest_obj(), obj_to_index() and objs_per_slab() that use struct page as
parameter. This patch converts it to struct slab including all callers, through
a coccinelle semantic patch.

// Options: --include-headers --no-includes --smpl-spacing include/linux/slab_def.h include/linux/slub_def.h mm/slab.h mm/kasan/*.c mm/kfence/kfence_test.c mm/memcontrol.c mm/slab.c mm/slub.c
// Note: needs coccinelle 1.1.1 to avoid breaking whitespace

@@
@@

-objs_per_slab_page(
+objs_per_slab(
 ...
 )
 { ... }

@@
@@

-objs_per_slab_page(
+objs_per_slab(
 ...
 )

@@
identifier fn =~ "obj_to_index|objs_per_slab";
@@

 fn(...,
-   const struct page *page
+   const struct slab *slab
    ,...)
 {
<...
(
- page_address(page)
+ slab_address(slab)
|
- page
+ slab
)
...>
 }

@@
identifier fn =~ "nearest_obj";
@@

 fn(...,
-   struct page *page
+   const struct slab *slab
    ,...)
 {
<...
(
- page_address(page)
+ slab_address(slab)
|
- page
+ slab
)
...>
 }

@@
identifier fn =~ "nearest_obj|obj_to_index|objs_per_slab";
expression E;
@@

 fn(...,
(
- slab_page(E)
+ E
|
- virt_to_page(E)
+ virt_to_slab(E)
|
- virt_to_head_page(E)
+ virt_to_slab(E)
|
- page
+ page_slab(page)
)
  ,...)

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Julia Lawall <julia.lawall@inria.fr>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <kasan-dev@googlegroups.com>
Cc: <cgroups@vger.kernel.org>
---
 include/linux/slab_def.h | 16 ++++++++--------
 include/linux/slub_def.h | 18 +++++++++---------
 mm/kasan/common.c        |  4 ++--
 mm/kasan/generic.c       |  2 +-
 mm/kasan/report.c        |  2 +-
 mm/kasan/report_tags.c   |  2 +-
 mm/kfence/kfence_test.c  |  4 ++--
 mm/memcontrol.c          |  4 ++--
 mm/slab.c                | 10 +++++-----
 mm/slab.h                |  4 ++--
 mm/slub.c                |  2 +-
 11 files changed, 34 insertions(+), 34 deletions(-)

diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index 3aa5e1e73ab6..e24c9aff6fed 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -87,11 +87,11 @@ struct kmem_cache {
 	struct kmem_cache_node *node[MAX_NUMNODES];
 };
 
-static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
+static inline void *nearest_obj(struct kmem_cache *cache, const struct slab *slab,
 				void *x)
 {
-	void *object = x - (x - page->s_mem) % cache->size;
-	void *last_object = page->s_mem + (cache->num - 1) * cache->size;
+	void *object = x - (x - slab->s_mem) % cache->size;
+	void *last_object = slab->s_mem + (cache->num - 1) * cache->size;
 
 	if (unlikely(object > last_object))
 		return last_object;
@@ -106,16 +106,16 @@ static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
  *   reciprocal_divide(offset, cache->reciprocal_buffer_size)
  */
 static inline unsigned int obj_to_index(const struct kmem_cache *cache,
-					const struct page *page, void *obj)
+					const struct slab *slab, void *obj)
 {
-	u32 offset = (obj - page->s_mem);
+	u32 offset = (obj - slab->s_mem);
 	return reciprocal_divide(offset, cache->reciprocal_buffer_size);
 }
 
-static inline int objs_per_slab_page(const struct kmem_cache *cache,
-				     const struct page *page)
+static inline int objs_per_slab(const struct kmem_cache *cache,
+				     const struct slab *slab)
 {
-	if (is_kfence_address(page_address(page)))
+	if (is_kfence_address(slab_address(slab)))
 		return 1;
 	return cache->num;
 }
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 8a9c2876ca89..33c5c0e3bd8d 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -158,11 +158,11 @@ static inline void sysfs_slab_release(struct kmem_cache *s)
 
 void *fixup_red_left(struct kmem_cache *s, void *p);
 
-static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
+static inline void *nearest_obj(struct kmem_cache *cache, const struct slab *slab,
 				void *x) {
-	void *object = x - (x - page_address(page)) % cache->size;
-	void *last_object = page_address(page) +
-		(page->objects - 1) * cache->size;
+	void *object = x - (x - slab_address(slab)) % cache->size;
+	void *last_object = slab_address(slab) +
+		(slab->objects - 1) * cache->size;
 	void *result = (unlikely(object > last_object)) ? last_object : object;
 
 	result = fixup_red_left(cache, result);
@@ -178,16 +178,16 @@ static inline unsigned int __obj_to_index(const struct kmem_cache *cache,
 }
 
 static inline unsigned int obj_to_index(const struct kmem_cache *cache,
-					const struct page *page, void *obj)
+					const struct slab *slab, void *obj)
 {
 	if (is_kfence_address(obj))
 		return 0;
-	return __obj_to_index(cache, page_address(page), obj);
+	return __obj_to_index(cache, slab_address(slab), obj);
 }
 
-static inline int objs_per_slab_page(const struct kmem_cache *cache,
-				     const struct page *page)
+static inline int objs_per_slab(const struct kmem_cache *cache,
+				     const struct slab *slab)
 {
-	return page->objects;
+	return slab->objects;
 }
 #endif /* _LINUX_SLUB_DEF_H */
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 8428da2aaf17..6a1cd2d38bff 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -298,7 +298,7 @@ static inline u8 assign_tag(struct kmem_cache *cache,
 	/* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */
 #ifdef CONFIG_SLAB
 	/* For SLAB assign tags based on the object index in the freelist. */
-	return (u8)obj_to_index(cache, virt_to_head_page(object), (void *)object);
+	return (u8)obj_to_index(cache, virt_to_slab(object), (void *)object);
 #else
 	/*
 	 * For SLUB assign a random tag during slab creation, otherwise reuse
@@ -341,7 +341,7 @@ static inline bool ____kasan_slab_free(struct kmem_cache *cache, void *object,
 	if (is_kfence_address(object))
 		return false;
 
-	if (unlikely(nearest_obj(cache, virt_to_head_page(object), object) !=
+	if (unlikely(nearest_obj(cache, virt_to_slab(object), object) !=
 	    object)) {
 		kasan_report_invalid_free(tagged_object, ip);
 		return true;
diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
index 84a038b07c6f..5d0b79416c4e 100644
--- a/mm/kasan/generic.c
+++ b/mm/kasan/generic.c
@@ -339,7 +339,7 @@ static void __kasan_record_aux_stack(void *addr, bool can_alloc)
 		return;
 
 	cache = page->slab_cache;
-	object = nearest_obj(cache, page, addr);
+	object = nearest_obj(cache, page_slab(page), addr);
 	alloc_meta = kasan_get_alloc_meta(cache, object);
 	if (!alloc_meta)
 		return;
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 0bc10f452f7e..e00999dc6499 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -249,7 +249,7 @@ static void print_address_description(void *addr, u8 tag)
 
 	if (page && PageSlab(page)) {
 		struct kmem_cache *cache = page->slab_cache;
-		void *object = nearest_obj(cache, page,	addr);
+		void *object = nearest_obj(cache, page_slab(page),	addr);
 
 		describe_object(cache, object, addr, tag);
 	}
diff --git a/mm/kasan/report_tags.c b/mm/kasan/report_tags.c
index 8a319fc16dab..06c21dd77493 100644
--- a/mm/kasan/report_tags.c
+++ b/mm/kasan/report_tags.c
@@ -23,7 +23,7 @@ const char *kasan_get_bug_type(struct kasan_access_info *info)
 	page = kasan_addr_to_page(addr);
 	if (page && PageSlab(page)) {
 		cache = page->slab_cache;
-		object = nearest_obj(cache, page, (void *)addr);
+		object = nearest_obj(cache, page_slab(page), (void *)addr);
 		alloc_meta = kasan_get_alloc_meta(cache, object);
 
 		if (alloc_meta) {
diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c
index 695030c1fff8..f7276711d7b9 100644
--- a/mm/kfence/kfence_test.c
+++ b/mm/kfence/kfence_test.c
@@ -291,8 +291,8 @@ static void *test_alloc(struct kunit *test, size_t size, gfp_t gfp, enum allocat
 			 * even for KFENCE objects; these are required so that
 			 * memcg accounting works correctly.
 			 */
-			KUNIT_EXPECT_EQ(test, obj_to_index(s, page, alloc), 0U);
-			KUNIT_EXPECT_EQ(test, objs_per_slab_page(s, page), 1);
+			KUNIT_EXPECT_EQ(test, obj_to_index(s, page_slab(page), alloc), 0U);
+			KUNIT_EXPECT_EQ(test, objs_per_slab(s, page_slab(page)), 1);
 
 			if (policy == ALLOCATE_ANY)
 				return alloc;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6863a834ed42..906edbd92436 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2819,7 +2819,7 @@ static struct mem_cgroup *get_mem_cgroup_from_objcg(struct obj_cgroup *objcg)
 int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
 				 gfp_t gfp, bool new_page)
 {
-	unsigned int objects = objs_per_slab_page(s, page);
+	unsigned int objects = objs_per_slab(s, page_slab(page));
 	unsigned long memcg_data;
 	void *vec;
 
@@ -2881,7 +2881,7 @@ struct mem_cgroup *mem_cgroup_from_obj(void *p)
 		struct obj_cgroup *objcg;
 		unsigned int off;
 
-		off = obj_to_index(page->slab_cache, page, p);
+		off = obj_to_index(page->slab_cache, page_slab(page), p);
 		objcg = page_objcgs(page)[off];
 		if (objcg)
 			return obj_cgroup_memcg(objcg);
diff --git a/mm/slab.c b/mm/slab.c
index f0447b087d02..785fffd527fe 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1560,7 +1560,7 @@ static void check_poison_obj(struct kmem_cache *cachep, void *objp)
 		struct slab *slab = virt_to_slab(objp);
 		unsigned int objnr;
 
-		objnr = obj_to_index(cachep, slab_page(slab), objp);
+		objnr = obj_to_index(cachep, slab, objp);
 		if (objnr) {
 			objp = index_to_obj(cachep, slab, objnr - 1);
 			realobj = (char *)objp + obj_offset(cachep);
@@ -2530,7 +2530,7 @@ static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slab)
 static void slab_put_obj(struct kmem_cache *cachep,
 			struct slab *slab, void *objp)
 {
-	unsigned int objnr = obj_to_index(cachep, slab_page(slab), objp);
+	unsigned int objnr = obj_to_index(cachep, slab, objp);
 #if DEBUG
 	unsigned int i;
 
@@ -2717,7 +2717,7 @@ static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
 	if (cachep->flags & SLAB_STORE_USER)
 		*dbg_userword(cachep, objp) = (void *)caller;
 
-	objnr = obj_to_index(cachep, slab_page(slab), objp);
+	objnr = obj_to_index(cachep, slab, objp);
 
 	BUG_ON(objnr >= cachep->num);
 	BUG_ON(objp != index_to_obj(cachep, slab, objnr));
@@ -3663,7 +3663,7 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
 	objp = object - obj_offset(cachep);
 	kpp->kp_data_offset = obj_offset(cachep);
 	slab = virt_to_slab(objp);
-	objnr = obj_to_index(cachep, slab_page(slab), objp);
+	objnr = obj_to_index(cachep, slab, objp);
 	objp = index_to_obj(cachep, slab, objnr);
 	kpp->kp_objp = objp;
 	if (DEBUG && cachep->flags & SLAB_STORE_USER)
@@ -4181,7 +4181,7 @@ void __check_heap_object(const void *ptr, unsigned long n,
 
 	/* Find and validate object. */
 	cachep = slab->slab_cache;
-	objnr = obj_to_index(cachep, slab_page(slab), (void *)ptr);
+	objnr = obj_to_index(cachep, slab, (void *)ptr);
 	BUG_ON(objnr >= cachep->num);
 
 	/* Find offset within object. */
diff --git a/mm/slab.h b/mm/slab.h
index 7376c9d8aa2b..15d109d8ec89 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -483,7 +483,7 @@ static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
 				continue;
 			}
 
-			off = obj_to_index(s, page, p[i]);
+			off = obj_to_index(s, page_slab(page), p[i]);
 			obj_cgroup_get(objcg);
 			page_objcgs(page)[off] = objcg;
 			mod_objcg_state(objcg, page_pgdat(page),
@@ -522,7 +522,7 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s_orig,
 		else
 			s = s_orig;
 
-		off = obj_to_index(s, page, p[i]);
+		off = obj_to_index(s, page_slab(page), p[i]);
 		objcg = objcgs[off];
 		if (!objcg)
 			continue;
diff --git a/mm/slub.c b/mm/slub.c
index f5344211d8cc..61aaaa662c5e 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4342,7 +4342,7 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
 #else
 	objp = objp0;
 #endif
-	objnr = obj_to_index(s, slab_page(slab), objp);
+	objnr = obj_to_index(s, slab, objp);
 	kpp->kp_data_offset = (unsigned long)((char *)objp0 - (char *)objp);
 	objp = base + s->size * objnr;
 	kpp->kp_objp = objp;
-- 
2.33.1

Re: [PATCH v2 22/33] mm: Convert struct page to struct slab in functions used by other subsystems

[Andrey Konovalov]

On Wed, Dec 1, 2021 at 7:15 PM Vlastimil Babka <vbabka@suse.cz> wrote:
>
> KASAN, KFENCE and memcg interact with SLAB or SLUB internals through functions
> nearest_obj(), obj_to_index() and objs_per_slab() that use struct page as
> parameter. This patch converts it to struct slab including all callers, through
> a coccinelle semantic patch.
>
> // Options: --include-headers --no-includes --smpl-spacing include/linux/slab_def.h include/linux/slub_def.h mm/slab.h mm/kasan/*.c mm/kfence/kfence_test.c mm/memcontrol.c mm/slab.c mm/slub.c
> // Note: needs coccinelle 1.1.1 to avoid breaking whitespace
>
> @@
> @@
>
> -objs_per_slab_page(
> +objs_per_slab(
>  ...
>  )
>  { ... }
>
> @@
> @@
>
> -objs_per_slab_page(
> +objs_per_slab(
>  ...
>  )
>
> @@
> identifier fn =~ "obj_to_index|objs_per_slab";
> @@
>
>  fn(...,
> -   const struct page *page
> +   const struct slab *slab
>     ,...)
>  {
> <...
> (
> - page_address(page)
> + slab_address(slab)
> |
> - page
> + slab
> )
> ...>
>  }
>
> @@
> identifier fn =~ "nearest_obj";
> @@
>
>  fn(...,
> -   struct page *page
> +   const struct slab *slab
>     ,...)
>  {
> <...
> (
> - page_address(page)
> + slab_address(slab)
> |
> - page
> + slab
> )
> ...>
>  }
>
> @@
> identifier fn =~ "nearest_obj|obj_to_index|objs_per_slab";
> expression E;
> @@
>
>  fn(...,
> (
> - slab_page(E)
> + E
> |
> - virt_to_page(E)
> + virt_to_slab(E)
> |
> - virt_to_head_page(E)
> + virt_to_slab(E)
> |
> - page
> + page_slab(page)
> )
>   ,...)
>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> Cc: Julia Lawall <julia.lawall@inria.fr>
> Cc: Luis Chamberlain <mcgrof@kernel.org>
> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
> Cc: Alexander Potapenko <glider@google.com>
> Cc: Andrey Konovalov <andreyknvl@gmail.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Cc: Marco Elver <elver@google.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
> Cc: <kasan-dev@googlegroups.com>
> Cc: <cgroups@vger.kernel.org>
> ---
>  include/linux/slab_def.h | 16 ++++++++--------
>  include/linux/slub_def.h | 18 +++++++++---------
>  mm/kasan/common.c        |  4 ++--
>  mm/kasan/generic.c       |  2 +-
>  mm/kasan/report.c        |  2 +-
>  mm/kasan/report_tags.c   |  2 +-
>  mm/kfence/kfence_test.c  |  4 ++--
>  mm/memcontrol.c          |  4 ++--
>  mm/slab.c                | 10 +++++-----
>  mm/slab.h                |  4 ++--
>  mm/slub.c                |  2 +-
>  11 files changed, 34 insertions(+), 34 deletions(-)
>
> diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
> index 3aa5e1e73ab6..e24c9aff6fed 100644
> --- a/include/linux/slab_def.h
> +++ b/include/linux/slab_def.h
> @@ -87,11 +87,11 @@ struct kmem_cache {
>         struct kmem_cache_node *node[MAX_NUMNODES];
>  };
>
> -static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
> +static inline void *nearest_obj(struct kmem_cache *cache, const struct slab *slab,
>                                 void *x)
>  {
> -       void *object = x - (x - page->s_mem) % cache->size;
> -       void *last_object = page->s_mem + (cache->num - 1) * cache->size;
> +       void *object = x - (x - slab->s_mem) % cache->size;
> +       void *last_object = slab->s_mem + (cache->num - 1) * cache->size;
>
>         if (unlikely(object > last_object))
>                 return last_object;
> @@ -106,16 +106,16 @@ static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
>   *   reciprocal_divide(offset, cache->reciprocal_buffer_size)
>   */
>  static inline unsigned int obj_to_index(const struct kmem_cache *cache,
> -                                       const struct page *page, void *obj)
> +                                       const struct slab *slab, void *obj)
>  {
> -       u32 offset = (obj - page->s_mem);
> +       u32 offset = (obj - slab->s_mem);
>         return reciprocal_divide(offset, cache->reciprocal_buffer_size);
>  }
>
> -static inline int objs_per_slab_page(const struct kmem_cache *cache,
> -                                    const struct page *page)
> +static inline int objs_per_slab(const struct kmem_cache *cache,
> +                                    const struct slab *slab)
>  {
> -       if (is_kfence_address(page_address(page)))
> +       if (is_kfence_address(slab_address(slab)))
>                 return 1;
>         return cache->num;
>  }
> diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
> index 8a9c2876ca89..33c5c0e3bd8d 100644
> --- a/include/linux/slub_def.h
> +++ b/include/linux/slub_def.h
> @@ -158,11 +158,11 @@ static inline void sysfs_slab_release(struct kmem_cache *s)
>
>  void *fixup_red_left(struct kmem_cache *s, void *p);
>
> -static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
> +static inline void *nearest_obj(struct kmem_cache *cache, const struct slab *slab,
>                                 void *x) {
> -       void *object = x - (x - page_address(page)) % cache->size;
> -       void *last_object = page_address(page) +
> -               (page->objects - 1) * cache->size;
> +       void *object = x - (x - slab_address(slab)) % cache->size;
> +       void *last_object = slab_address(slab) +
> +               (slab->objects - 1) * cache->size;
>         void *result = (unlikely(object > last_object)) ? last_object : object;
>
>         result = fixup_red_left(cache, result);
> @@ -178,16 +178,16 @@ static inline unsigned int __obj_to_index(const struct kmem_cache *cache,
>  }
>
>  static inline unsigned int obj_to_index(const struct kmem_cache *cache,
> -                                       const struct page *page, void *obj)
> +                                       const struct slab *slab, void *obj)
>  {
>         if (is_kfence_address(obj))
>                 return 0;
> -       return __obj_to_index(cache, page_address(page), obj);
> +       return __obj_to_index(cache, slab_address(slab), obj);
>  }
>
> -static inline int objs_per_slab_page(const struct kmem_cache *cache,
> -                                    const struct page *page)
> +static inline int objs_per_slab(const struct kmem_cache *cache,
> +                                    const struct slab *slab)
>  {
> -       return page->objects;
> +       return slab->objects;
>  }
>  #endif /* _LINUX_SLUB_DEF_H */
> diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> index 8428da2aaf17..6a1cd2d38bff 100644
> --- a/mm/kasan/common.c
> +++ b/mm/kasan/common.c
> @@ -298,7 +298,7 @@ static inline u8 assign_tag(struct kmem_cache *cache,
>         /* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */
>  #ifdef CONFIG_SLAB
>         /* For SLAB assign tags based on the object index in the freelist. */
> -       return (u8)obj_to_index(cache, virt_to_head_page(object), (void *)object);
> +       return (u8)obj_to_index(cache, virt_to_slab(object), (void *)object);
>  #else
>         /*
>          * For SLUB assign a random tag during slab creation, otherwise reuse
> @@ -341,7 +341,7 @@ static inline bool ____kasan_slab_free(struct kmem_cache *cache, void *object,
>         if (is_kfence_address(object))
>                 return false;
>
> -       if (unlikely(nearest_obj(cache, virt_to_head_page(object), object) !=
> +       if (unlikely(nearest_obj(cache, virt_to_slab(object), object) !=
>             object)) {
>                 kasan_report_invalid_free(tagged_object, ip);
>                 return true;
> diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
> index 84a038b07c6f..5d0b79416c4e 100644
> --- a/mm/kasan/generic.c
> +++ b/mm/kasan/generic.c
> @@ -339,7 +339,7 @@ static void __kasan_record_aux_stack(void *addr, bool can_alloc)
>                 return;
>
>         cache = page->slab_cache;
> -       object = nearest_obj(cache, page, addr);
> +       object = nearest_obj(cache, page_slab(page), addr);
>         alloc_meta = kasan_get_alloc_meta(cache, object);
>         if (!alloc_meta)
>                 return;
> diff --git a/mm/kasan/report.c b/mm/kasan/report.c
> index 0bc10f452f7e..e00999dc6499 100644
> --- a/mm/kasan/report.c
> +++ b/mm/kasan/report.c
> @@ -249,7 +249,7 @@ static void print_address_description(void *addr, u8 tag)
>
>         if (page && PageSlab(page)) {
>                 struct kmem_cache *cache = page->slab_cache;
> -               void *object = nearest_obj(cache, page, addr);
> +               void *object = nearest_obj(cache, page_slab(page),      addr);
>
>                 describe_object(cache, object, addr, tag);
>         }
> diff --git a/mm/kasan/report_tags.c b/mm/kasan/report_tags.c
> index 8a319fc16dab..06c21dd77493 100644
> --- a/mm/kasan/report_tags.c
> +++ b/mm/kasan/report_tags.c
> @@ -23,7 +23,7 @@ const char *kasan_get_bug_type(struct kasan_access_info *info)
>         page = kasan_addr_to_page(addr);
>         if (page && PageSlab(page)) {
>                 cache = page->slab_cache;
> -               object = nearest_obj(cache, page, (void *)addr);
> +               object = nearest_obj(cache, page_slab(page), (void *)addr);
>                 alloc_meta = kasan_get_alloc_meta(cache, object);
>
>                 if (alloc_meta) {
> diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c
> index 695030c1fff8..f7276711d7b9 100644
> --- a/mm/kfence/kfence_test.c
> +++ b/mm/kfence/kfence_test.c
> @@ -291,8 +291,8 @@ static void *test_alloc(struct kunit *test, size_t size, gfp_t gfp, enum allocat
>                          * even for KFENCE objects; these are required so that
>                          * memcg accounting works correctly.
>                          */
> -                       KUNIT_EXPECT_EQ(test, obj_to_index(s, page, alloc), 0U);
> -                       KUNIT_EXPECT_EQ(test, objs_per_slab_page(s, page), 1);
> +                       KUNIT_EXPECT_EQ(test, obj_to_index(s, page_slab(page), alloc), 0U);
> +                       KUNIT_EXPECT_EQ(test, objs_per_slab(s, page_slab(page)), 1);
>
>                         if (policy == ALLOCATE_ANY)
>                                 return alloc;
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 6863a834ed42..906edbd92436 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2819,7 +2819,7 @@ static struct mem_cgroup *get_mem_cgroup_from_objcg(struct obj_cgroup *objcg)
>  int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
>                                  gfp_t gfp, bool new_page)
>  {
> -       unsigned int objects = objs_per_slab_page(s, page);
> +       unsigned int objects = objs_per_slab(s, page_slab(page));
>         unsigned long memcg_data;
>         void *vec;
>
> @@ -2881,7 +2881,7 @@ struct mem_cgroup *mem_cgroup_from_obj(void *p)
>                 struct obj_cgroup *objcg;
>                 unsigned int off;
>
> -               off = obj_to_index(page->slab_cache, page, p);
> +               off = obj_to_index(page->slab_cache, page_slab(page), p);
>                 objcg = page_objcgs(page)[off];
>                 if (objcg)
>                         return obj_cgroup_memcg(objcg);
> diff --git a/mm/slab.c b/mm/slab.c
> index f0447b087d02..785fffd527fe 100644
> --- a/mm/slab.c
> +++ b/mm/slab.c
> @@ -1560,7 +1560,7 @@ static void check_poison_obj(struct kmem_cache *cachep, void *objp)
>                 struct slab *slab = virt_to_slab(objp);
>                 unsigned int objnr;
>
> -               objnr = obj_to_index(cachep, slab_page(slab), objp);
> +               objnr = obj_to_index(cachep, slab, objp);
>                 if (objnr) {
>                         objp = index_to_obj(cachep, slab, objnr - 1);
>                         realobj = (char *)objp + obj_offset(cachep);
> @@ -2530,7 +2530,7 @@ static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slab)
>  static void slab_put_obj(struct kmem_cache *cachep,
>                         struct slab *slab, void *objp)
>  {
> -       unsigned int objnr = obj_to_index(cachep, slab_page(slab), objp);
> +       unsigned int objnr = obj_to_index(cachep, slab, objp);
>  #if DEBUG
>         unsigned int i;
>
> @@ -2717,7 +2717,7 @@ static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
>         if (cachep->flags & SLAB_STORE_USER)
>                 *dbg_userword(cachep, objp) = (void *)caller;
>
> -       objnr = obj_to_index(cachep, slab_page(slab), objp);
> +       objnr = obj_to_index(cachep, slab, objp);
>
>         BUG_ON(objnr >= cachep->num);
>         BUG_ON(objp != index_to_obj(cachep, slab, objnr));
> @@ -3663,7 +3663,7 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
>         objp = object - obj_offset(cachep);
>         kpp->kp_data_offset = obj_offset(cachep);
>         slab = virt_to_slab(objp);
> -       objnr = obj_to_index(cachep, slab_page(slab), objp);
> +       objnr = obj_to_index(cachep, slab, objp);
>         objp = index_to_obj(cachep, slab, objnr);
>         kpp->kp_objp = objp;
>         if (DEBUG && cachep->flags & SLAB_STORE_USER)
> @@ -4181,7 +4181,7 @@ void __check_heap_object(const void *ptr, unsigned long n,
>
>         /* Find and validate object. */
>         cachep = slab->slab_cache;
> -       objnr = obj_to_index(cachep, slab_page(slab), (void *)ptr);
> +       objnr = obj_to_index(cachep, slab, (void *)ptr);
>         BUG_ON(objnr >= cachep->num);
>
>         /* Find offset within object. */
> diff --git a/mm/slab.h b/mm/slab.h
> index 7376c9d8aa2b..15d109d8ec89 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -483,7 +483,7 @@ static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
>                                 continue;
>                         }
>
> -                       off = obj_to_index(s, page, p[i]);
> +                       off = obj_to_index(s, page_slab(page), p[i]);
>                         obj_cgroup_get(objcg);
>                         page_objcgs(page)[off] = objcg;
>                         mod_objcg_state(objcg, page_pgdat(page),
> @@ -522,7 +522,7 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s_orig,
>                 else
>                         s = s_orig;
>
> -               off = obj_to_index(s, page, p[i]);
> +               off = obj_to_index(s, page_slab(page), p[i]);
>                 objcg = objcgs[off];
>                 if (!objcg)
>                         continue;
> diff --git a/mm/slub.c b/mm/slub.c
> index f5344211d8cc..61aaaa662c5e 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -4342,7 +4342,7 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
>  #else
>         objp = objp0;
>  #endif
> -       objnr = obj_to_index(s, slab_page(slab), objp);
> +       objnr = obj_to_index(s, slab, objp);
>         kpp->kp_data_offset = (unsigned long)((char *)objp0 - (char *)objp);
>         objp = base + s->size * objnr;
>         kpp->kp_objp = objp;
> --
> 2.33.1
>

Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>

Thanks!

Re: [PATCH v2 22/33] mm: Convert struct page to struct slab in functions used by other subsystems

[Johannes Weiner]

On Wed, Dec 01, 2021 at 07:14:59PM +0100, Vlastimil Babka wrote:
> KASAN, KFENCE and memcg interact with SLAB or SLUB internals through functions
> nearest_obj(), obj_to_index() and objs_per_slab() that use struct page as
> parameter. This patch converts it to struct slab including all callers, through
> a coccinelle semantic patch.
> 
> // Options: --include-headers --no-includes --smpl-spacing include/linux/slab_def.h include/linux/slub_def.h mm/slab.h mm/kasan/*.c mm/kfence/kfence_test.c mm/memcontrol.c mm/slab.c mm/slub.c
> // Note: needs coccinelle 1.1.1 to avoid breaking whitespace
> 
> @@
> @@
> 
> -objs_per_slab_page(
> +objs_per_slab(
>  ...
>  )
>  { ... }
> 
> @@
> @@
> 
> -objs_per_slab_page(
> +objs_per_slab(
>  ...
>  )
> 
> @@
> identifier fn =~ "obj_to_index|objs_per_slab";
> @@
> 
>  fn(...,
> -   const struct page *page
> +   const struct slab *slab
>     ,...)
>  {
> <...
> (
> - page_address(page)
> + slab_address(slab)
> |
> - page
> + slab
> )
> ...>
>  }
> 
> @@
> identifier fn =~ "nearest_obj";
> @@
> 
>  fn(...,
> -   struct page *page
> +   const struct slab *slab
>     ,...)
>  {
> <...
> (
> - page_address(page)
> + slab_address(slab)
> |
> - page
> + slab
> )
> ...>
>  }
> 
> @@
> identifier fn =~ "nearest_obj|obj_to_index|objs_per_slab";
> expression E;
> @@
> 
>  fn(...,
> (
> - slab_page(E)
> + E
> |
> - virt_to_page(E)
> + virt_to_slab(E)
> |
> - virt_to_head_page(E)
> + virt_to_slab(E)
> |
> - page
> + page_slab(page)
> )
>   ,...)
> 
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> Cc: Julia Lawall <julia.lawall@inria.fr>
> Cc: Luis Chamberlain <mcgrof@kernel.org>
> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
> Cc: Alexander Potapenko <glider@google.com>
> Cc: Andrey Konovalov <andreyknvl@gmail.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Cc: Marco Elver <elver@google.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
> Cc: <kasan-dev@googlegroups.com>
> Cc: <cgroups@vger.kernel.org>

LGTM.

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

[PATCH v2 23/33] mm/memcg: Convert slab objcgs from struct page to struct slab

[Vlastimil Babka]

page->memcg_data is used with MEMCG_DATA_OBJCGS flag only for slab pages
so convert all the related infrastructure to struct slab.

To avoid include cycles, move the inline definitions of slab_objcgs() and
slab_objcgs_check() from memcontrol.h to mm/slab.h.

This is not just mechanistic changing of types and names. Now in
mem_cgroup_from_obj() we use PageSlab flag to decide if we interpret the page
as slab, instead of relying on MEMCG_DATA_OBJCGS bit checked in
page_objcgs_check() (now slab_objcgs_check()). Similarly in
memcg_slab_free_hook() where we can encounter kmalloc_large() pages (here the
PageSlab flag check is implied by virt_to_slab()).

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <cgroups@vger.kernel.org>
---
 include/linux/memcontrol.h |  48 ------------------
 mm/memcontrol.c            |  43 +++++++++-------
 mm/slab.h                  | 101 ++++++++++++++++++++++++++++---------
 3 files changed, 103 insertions(+), 89 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 0c5c403f4be6..e34112f6a369 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -536,45 +536,6 @@ static inline bool folio_memcg_kmem(struct folio *folio)
 	return folio->memcg_data & MEMCG_DATA_KMEM;
 }
 
-/*
- * page_objcgs - get the object cgroups vector associated with a page
- * @page: a pointer to the page struct
- *
- * Returns a pointer to the object cgroups vector associated with the page,
- * or NULL. This function assumes that the page is known to have an
- * associated object cgroups vector. It's not safe to call this function
- * against pages, which might have an associated memory cgroup: e.g.
- * kernel stack pages.
- */
-static inline struct obj_cgroup **page_objcgs(struct page *page)
-{
-	unsigned long memcg_data = READ_ONCE(page->memcg_data);
-
-	VM_BUG_ON_PAGE(memcg_data && !(memcg_data & MEMCG_DATA_OBJCGS), page);
-	VM_BUG_ON_PAGE(memcg_data & MEMCG_DATA_KMEM, page);
-
-	return (struct obj_cgroup **)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
-}
-
-/*
- * page_objcgs_check - get the object cgroups vector associated with a page
- * @page: a pointer to the page struct
- *
- * Returns a pointer to the object cgroups vector associated with the page,
- * or NULL. This function is safe to use if the page can be directly associated
- * with a memory cgroup.
- */
-static inline struct obj_cgroup **page_objcgs_check(struct page *page)
-{
-	unsigned long memcg_data = READ_ONCE(page->memcg_data);
-
-	if (!memcg_data || !(memcg_data & MEMCG_DATA_OBJCGS))
-		return NULL;
-
-	VM_BUG_ON_PAGE(memcg_data & MEMCG_DATA_KMEM, page);
-
-	return (struct obj_cgroup **)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
-}
 
 #else
 static inline bool folio_memcg_kmem(struct folio *folio)
@@ -582,15 +543,6 @@ static inline bool folio_memcg_kmem(struct folio *folio)
 	return false;
 }
 
-static inline struct obj_cgroup **page_objcgs(struct page *page)
-{
-	return NULL;
-}
-
-static inline struct obj_cgroup **page_objcgs_check(struct page *page)
-{
-	return NULL;
-}
 #endif
 
 static inline bool PageMemcgKmem(struct page *page)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 906edbd92436..522fff11d6d1 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2816,31 +2816,31 @@ static struct mem_cgroup *get_mem_cgroup_from_objcg(struct obj_cgroup *objcg)
  */
 #define OBJCGS_CLEAR_MASK	(__GFP_DMA | __GFP_RECLAIMABLE | __GFP_ACCOUNT)
 
-int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
-				 gfp_t gfp, bool new_page)
+int memcg_alloc_slab_cgroups(struct slab *slab, struct kmem_cache *s,
+				 gfp_t gfp, bool new_slab)
 {
-	unsigned int objects = objs_per_slab(s, page_slab(page));
+	unsigned int objects = objs_per_slab(s, slab);
 	unsigned long memcg_data;
 	void *vec;
 
 	gfp &= ~OBJCGS_CLEAR_MASK;
 	vec = kcalloc_node(objects, sizeof(struct obj_cgroup *), gfp,
-			   page_to_nid(page));
+			   slab_nid(slab));
 	if (!vec)
 		return -ENOMEM;
 
 	memcg_data = (unsigned long) vec | MEMCG_DATA_OBJCGS;
-	if (new_page) {
+	if (new_slab) {
 		/*
-		 * If the slab page is brand new and nobody can yet access
-		 * it's memcg_data, no synchronization is required and
-		 * memcg_data can be simply assigned.
+		 * If the slab is brand new and nobody can yet access its
+		 * memcg_data, no synchronization is required and memcg_data can
+		 * be simply assigned.
 		 */
-		page->memcg_data = memcg_data;
-	} else if (cmpxchg(&page->memcg_data, 0, memcg_data)) {
+		slab->memcg_data = memcg_data;
+	} else if (cmpxchg(&slab->memcg_data, 0, memcg_data)) {
 		/*
-		 * If the slab page is already in use, somebody can allocate
-		 * and assign obj_cgroups in parallel. In this case the existing
+		 * If the slab is already in use, somebody can allocate and
+		 * assign obj_cgroups in parallel. In this case the existing
 		 * objcg vector should be reused.
 		 */
 		kfree(vec);
@@ -2865,24 +2865,31 @@ int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
  */
 struct mem_cgroup *mem_cgroup_from_obj(void *p)
 {
-	struct page *page;
+	struct folio *folio;
 
 	if (mem_cgroup_disabled())
 		return NULL;
 
-	page = virt_to_head_page(p);
+	folio = virt_to_folio(p);
 
 	/*
 	 * Slab objects are accounted individually, not per-page.
 	 * Memcg membership data for each individual object is saved in
 	 * the page->obj_cgroups.
 	 */
-	if (page_objcgs_check(page)) {
+	if (folio_test_slab(folio)) {
+		struct obj_cgroup **objcgs;
 		struct obj_cgroup *objcg;
+		struct slab *slab;
 		unsigned int off;
 
-		off = obj_to_index(page->slab_cache, page_slab(page), p);
-		objcg = page_objcgs(page)[off];
+		slab = folio_slab(folio);
+		objcgs = slab_objcgs_check(slab);
+		if (!objcgs)
+			return NULL;
+
+		off = obj_to_index(slab->slab_cache, slab, p);
+		objcg = objcgs[off];
 		if (objcg)
 			return obj_cgroup_memcg(objcg);
 
@@ -2896,7 +2903,7 @@ struct mem_cgroup *mem_cgroup_from_obj(void *p)
 	 * page_memcg_check(page) will guarantee that a proper memory
 	 * cgroup pointer or NULL will be returned.
 	 */
-	return page_memcg_check(page);
+	return page_memcg_check(folio_page(folio, 0));
 }
 
 __always_inline struct obj_cgroup *get_obj_cgroup_from_current(void)
diff --git a/mm/slab.h b/mm/slab.h
index 15d109d8ec89..0760f20686a7 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -412,15 +412,56 @@ static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t fla
 }
 
 #ifdef CONFIG_MEMCG_KMEM
-int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
-				 gfp_t gfp, bool new_page);
+/*
+ * slab_objcgs - get the object cgroups vector associated with a slab
+ * @slab: a pointer to the slab struct
+ *
+ * Returns a pointer to the object cgroups vector associated with the slab,
+ * or NULL. This function assumes that the slab is known to have an
+ * associated object cgroups vector. It's not safe to call this function
+ * against slabs with underlying pages, which might have an associated memory
+ * cgroup: e.g.  kernel stack pages.
+ */
+static inline struct obj_cgroup **slab_objcgs(struct slab *slab)
+{
+	unsigned long memcg_data = READ_ONCE(slab->memcg_data);
+
+	VM_BUG_ON_PAGE(memcg_data && !(memcg_data & MEMCG_DATA_OBJCGS),
+							slab_page(slab));
+	VM_BUG_ON_PAGE(memcg_data & MEMCG_DATA_KMEM, slab_page(slab));
+
+	return (struct obj_cgroup **)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
+}
+
+/*
+ * slab_objcgs_check - get the object cgroups vector associated with a slab
+ * @slab: a pointer to the slab struct
+ *
+ * Returns a pointer to the object cgroups vector associated with the slab, or
+ * NULL. This function is safe to use if the underlying page can be directly
+ * associated with a memory cgroup.
+ */
+static inline struct obj_cgroup **slab_objcgs_check(struct slab *slab)
+{
+	unsigned long memcg_data = READ_ONCE(slab->memcg_data);
+
+	if (!memcg_data || !(memcg_data & MEMCG_DATA_OBJCGS))
+		return NULL;
+
+	VM_BUG_ON_PAGE(memcg_data & MEMCG_DATA_KMEM, slab_page(slab));
+
+	return (struct obj_cgroup **)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
+}
+
+int memcg_alloc_slab_cgroups(struct slab *slab, struct kmem_cache *s,
+				 gfp_t gfp, bool new_slab);
 void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
 		     enum node_stat_item idx, int nr);
 
-static inline void memcg_free_page_obj_cgroups(struct page *page)
+static inline void memcg_free_slab_cgroups(struct slab *slab)
 {
-	kfree(page_objcgs(page));
-	page->memcg_data = 0;
+	kfree(slab_objcgs(slab));
+	slab->memcg_data = 0;
 }
 
 static inline size_t obj_full_size(struct kmem_cache *s)
@@ -465,7 +506,7 @@ static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
 					      gfp_t flags, size_t size,
 					      void **p)
 {
-	struct page *page;
+	struct slab *slab;
 	unsigned long off;
 	size_t i;
 
@@ -474,19 +515,19 @@ static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
 
 	for (i = 0; i < size; i++) {
 		if (likely(p[i])) {
-			page = virt_to_head_page(p[i]);
+			slab = virt_to_slab(p[i]);
 
-			if (!page_objcgs(page) &&
-			    memcg_alloc_page_obj_cgroups(page, s, flags,
+			if (!slab_objcgs(slab) &&
+			    memcg_alloc_slab_cgroups(slab, s, flags,
 							 false)) {
 				obj_cgroup_uncharge(objcg, obj_full_size(s));
 				continue;
 			}
 
-			off = obj_to_index(s, page_slab(page), p[i]);
+			off = obj_to_index(s, slab, p[i]);
 			obj_cgroup_get(objcg);
-			page_objcgs(page)[off] = objcg;
-			mod_objcg_state(objcg, page_pgdat(page),
+			slab_objcgs(slab)[off] = objcg;
+			mod_objcg_state(objcg, slab_pgdat(slab),
 					cache_vmstat_idx(s), obj_full_size(s));
 		} else {
 			obj_cgroup_uncharge(objcg, obj_full_size(s));
@@ -501,7 +542,7 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s_orig,
 	struct kmem_cache *s;
 	struct obj_cgroup **objcgs;
 	struct obj_cgroup *objcg;
-	struct page *page;
+	struct slab *slab;
 	unsigned int off;
 	int i;
 
@@ -512,43 +553,57 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s_orig,
 		if (unlikely(!p[i]))
 			continue;
 
-		page = virt_to_head_page(p[i]);
-		objcgs = page_objcgs_check(page);
+		slab = virt_to_slab(p[i]);
+		/* we could be given a kmalloc_large() object, skip those */
+		if (!slab)
+			continue;
+
+		objcgs = slab_objcgs_check(slab);
 		if (!objcgs)
 			continue;
 
 		if (!s_orig)
-			s = page->slab_cache;
+			s = slab->slab_cache;
 		else
 			s = s_orig;
 
-		off = obj_to_index(s, page_slab(page), p[i]);
+		off = obj_to_index(s, slab, p[i]);
 		objcg = objcgs[off];
 		if (!objcg)
 			continue;
 
 		objcgs[off] = NULL;
 		obj_cgroup_uncharge(objcg, obj_full_size(s));
-		mod_objcg_state(objcg, page_pgdat(page), cache_vmstat_idx(s),
+		mod_objcg_state(objcg, slab_pgdat(slab), cache_vmstat_idx(s),
 				-obj_full_size(s));
 		obj_cgroup_put(objcg);
 	}
 }
 
 #else /* CONFIG_MEMCG_KMEM */
+static inline struct obj_cgroup **slab_objcgs(struct slab *slab)
+{
+	return NULL;
+}
+
+static inline struct obj_cgroup **slab_objcgs_check(struct slab *slab)
+{
+	return NULL;
+}
+
 static inline struct mem_cgroup *memcg_from_slab_obj(void *ptr)
 {
 	return NULL;
 }
 
-static inline int memcg_alloc_page_obj_cgroups(struct page *page,
+static inline int memcg_alloc_slab_cgroups(struct slab *slab,
 					       struct kmem_cache *s, gfp_t gfp,
-					       bool new_page)
+					       bool new_slab)
 {
 	return 0;
 }
 
-static inline void memcg_free_page_obj_cgroups(struct page *page)
+static inline void memcg_free_slab_cgroups(struct slab *slab)
 {
 }
 
@@ -587,7 +642,7 @@ static __always_inline void account_slab(struct slab *slab, int order,
 					 struct kmem_cache *s, gfp_t gfp)
 {
 	if (memcg_kmem_enabled() && (s->flags & SLAB_ACCOUNT))
-		memcg_alloc_page_obj_cgroups(slab_page(slab), s, gfp, true);
+		memcg_alloc_slab_cgroups(slab, s, gfp, true);
 
 	mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
 			    PAGE_SIZE << order);
@@ -597,7 +652,7 @@ static __always_inline void unaccount_slab(struct slab *slab, int order,
 					   struct kmem_cache *s)
 {
 	if (memcg_kmem_enabled())
-		memcg_free_page_obj_cgroups(slab_page(slab));
+		memcg_free_slab_cgroups(slab);
 
 	mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
 			    -(PAGE_SIZE << order));
-- 
2.33.1

Re: [PATCH v2 23/33] mm/memcg: Convert slab objcgs from struct page to struct slab

[Johannes Weiner]

On Wed, Dec 01, 2021 at 07:15:00PM +0100, Vlastimil Babka wrote:
> page->memcg_data is used with MEMCG_DATA_OBJCGS flag only for slab pages
> so convert all the related infrastructure to struct slab.
> 
> To avoid include cycles, move the inline definitions of slab_objcgs() and
> slab_objcgs_check() from memcontrol.h to mm/slab.h.
> 
> This is not just mechanistic changing of types and names. Now in
> mem_cgroup_from_obj() we use PageSlab flag to decide if we interpret the page
> as slab, instead of relying on MEMCG_DATA_OBJCGS bit checked in
> page_objcgs_check() (now slab_objcgs_check()). Similarly in
> memcg_slab_free_hook() where we can encounter kmalloc_large() pages (here the
> PageSlab flag check is implied by virt_to_slab()).

Yup, this is great.

> @@ -2865,24 +2865,31 @@ int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
>   */
>  struct mem_cgroup *mem_cgroup_from_obj(void *p)
>  {
> -	struct page *page;
> +	struct folio *folio;
>  
>  	if (mem_cgroup_disabled())
>  		return NULL;
>  
> -	page = virt_to_head_page(p);
> +	folio = virt_to_folio(p);
>  
>  	/*
>  	 * Slab objects are accounted individually, not per-page.
>  	 * Memcg membership data for each individual object is saved in
>  	 * the page->obj_cgroups.
>  	 */
> -	if (page_objcgs_check(page)) {
> +	if (folio_test_slab(folio)) {
> +		struct obj_cgroup **objcgs;
>  		struct obj_cgroup *objcg;
> +		struct slab *slab;
>  		unsigned int off;
>  
> -		off = obj_to_index(page->slab_cache, page_slab(page), p);
> -		objcg = page_objcgs(page)[off];
> +		slab = folio_slab(folio);
> +		objcgs = slab_objcgs_check(slab);

AFAICS the change to the _check() variant was accidental.

folio_test_slab() makes sure it's a slab page, so the legit options
for memcg_data are NULL or |MEMCG_DATA_OBJCGS; using slab_objcgs()
here would include the proper asserts, like page_objcgs() used to.

Re: [PATCH v2 23/33] mm/memcg: Convert slab objcgs from struct page to struct slab

[Vlastimil Babka]

On 12/14/21 15:43, Johannes Weiner wrote:
> On Wed, Dec 01, 2021 at 07:15:00PM +0100, Vlastimil Babka wrote:
>> page->memcg_data is used with MEMCG_DATA_OBJCGS flag only for slab pages
>> so convert all the related infrastructure to struct slab.
>> 
>> To avoid include cycles, move the inline definitions of slab_objcgs() and
>> slab_objcgs_check() from memcontrol.h to mm/slab.h.
>> 
>> This is not just mechanistic changing of types and names. Now in
>> mem_cgroup_from_obj() we use PageSlab flag to decide if we interpret the page
>> as slab, instead of relying on MEMCG_DATA_OBJCGS bit checked in
>> page_objcgs_check() (now slab_objcgs_check()). Similarly in
>> memcg_slab_free_hook() where we can encounter kmalloc_large() pages (here the
>> PageSlab flag check is implied by virt_to_slab()).
> 
> Yup, this is great.
> 
>> @@ -2865,24 +2865,31 @@ int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
>>   */
>>  struct mem_cgroup *mem_cgroup_from_obj(void *p)
>>  {
>> -	struct page *page;
>> +	struct folio *folio;
>>  
>>  	if (mem_cgroup_disabled())
>>  		return NULL;
>>  
>> -	page = virt_to_head_page(p);
>> +	folio = virt_to_folio(p);
>>  
>>  	/*
>>  	 * Slab objects are accounted individually, not per-page.
>>  	 * Memcg membership data for each individual object is saved in
>>  	 * the page->obj_cgroups.
>>  	 */
>> -	if (page_objcgs_check(page)) {
>> +	if (folio_test_slab(folio)) {
>> +		struct obj_cgroup **objcgs;
>>  		struct obj_cgroup *objcg;
>> +		struct slab *slab;
>>  		unsigned int off;
>>  
>> -		off = obj_to_index(page->slab_cache, page_slab(page), p);
>> -		objcg = page_objcgs(page)[off];
>> +		slab = folio_slab(folio);
>> +		objcgs = slab_objcgs_check(slab);
> 
> AFAICS the change to the _check() variant was accidental.
> 
> folio_test_slab() makes sure it's a slab page, so the legit options
> for memcg_data are NULL or |MEMCG_DATA_OBJCGS; using slab_objcgs()
> here would include the proper asserts, like page_objcgs() used to.

Well spotted. On closer look, it's actually the same in
memcg_slab_free_hook() where I also added a folio_test_slab() as part of
virt_to_slab(). In fact it means page_objcgs_check() can be just deleted
instead of replaced by slab_objcgs_check(). Thanks!

[PATCH v2 24/33] mm/slob: Convert SLOB to use struct slab

[Vlastimil Babka]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

Use struct slab throughout the slob allocator.

[ vbabka@suse.cz: don't introduce wrappers for PageSlobFree in mm/slab.h just
  for the single callers being wrappers in mm/slob.c ]

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slob.c | 34 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/mm/slob.c b/mm/slob.c
index d2d15e7f191c..d3512bcc3141 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -105,21 +105,21 @@ static LIST_HEAD(free_slob_large);
 /*
  * slob_page_free: true for pages on free_slob_pages list.
  */
-static inline int slob_page_free(struct page *sp)
+static inline int slob_page_free(struct slab *slab)
 {
-	return PageSlobFree(sp);
+	return PageSlobFree(slab_page(slab));
 }
 
-static void set_slob_page_free(struct page *sp, struct list_head *list)
+static void set_slob_page_free(struct slab *slab, struct list_head *list)
 {
-	list_add(&sp->slab_list, list);
-	__SetPageSlobFree(sp);
+	list_add(&slab->slab_list, list);
+	__SetPageSlobFree(slab_page(slab));
 }
 
-static inline void clear_slob_page_free(struct page *sp)
+static inline void clear_slob_page_free(struct slab *slab)
 {
-	list_del(&sp->slab_list);
-	__ClearPageSlobFree(sp);
+	list_del(&slab->slab_list);
+	__ClearPageSlobFree(slab_page(slab));
 }
 
 #define SLOB_UNIT sizeof(slob_t)
@@ -234,7 +234,7 @@ static void slob_free_pages(void *b, int order)
  *         freelist, in this case @page_removed_from_list will be set to
  *         true (set to false otherwise).
  */
-static void *slob_page_alloc(struct page *sp, size_t size, int align,
+static void *slob_page_alloc(struct slab *sp, size_t size, int align,
 			      int align_offset, bool *page_removed_from_list)
 {
 	slob_t *prev, *cur, *aligned = NULL;
@@ -301,7 +301,7 @@ static void *slob_page_alloc(struct page *sp, size_t size, int align,
 static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
 							int align_offset)
 {
-	struct page *sp;
+	struct slab *sp;
 	struct list_head *slob_list;
 	slob_t *b = NULL;
 	unsigned long flags;
@@ -323,7 +323,7 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
 		 * If there's a node specification, search for a partial
 		 * page with a matching node id in the freelist.
 		 */
-		if (node != NUMA_NO_NODE && page_to_nid(sp) != node)
+		if (node != NUMA_NO_NODE && slab_nid(sp) != node)
 			continue;
 #endif
 		/* Enough room on this page? */
@@ -358,8 +358,8 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
 		b = slob_new_pages(gfp & ~__GFP_ZERO, 0, node);
 		if (!b)
 			return NULL;
-		sp = virt_to_page(b);
-		__SetPageSlab(sp);
+		sp = virt_to_slab(b);
+		__SetPageSlab(slab_page(sp));
 
 		spin_lock_irqsave(&slob_lock, flags);
 		sp->units = SLOB_UNITS(PAGE_SIZE);
@@ -381,7 +381,7 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
  */
 static void slob_free(void *block, int size)
 {
-	struct page *sp;
+	struct slab *sp;
 	slob_t *prev, *next, *b = (slob_t *)block;
 	slobidx_t units;
 	unsigned long flags;
@@ -391,7 +391,7 @@ static void slob_free(void *block, int size)
 		return;
 	BUG_ON(!size);
 
-	sp = virt_to_page(block);
+	sp = virt_to_slab(block);
 	units = SLOB_UNITS(size);
 
 	spin_lock_irqsave(&slob_lock, flags);
@@ -401,8 +401,8 @@ static void slob_free(void *block, int size)
 		if (slob_page_free(sp))
 			clear_slob_page_free(sp);
 		spin_unlock_irqrestore(&slob_lock, flags);
-		__ClearPageSlab(sp);
-		page_mapcount_reset(sp);
+		__ClearPageSlab(slab_page(sp));
+		page_mapcount_reset(slab_page(sp));
 		slob_free_pages(b, 0);
 		return;
 	}
-- 
2.33.1

Re: [PATCH v2 24/33] mm/slob: Convert SLOB to use struct slab

[Hyeonggon Yoo]

On Wed, Dec 01, 2021 at 07:15:01PM +0100, Vlastimil Babka wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> Use struct slab throughout the slob allocator.
> 
> [ vbabka@suse.cz: don't introduce wrappers for PageSlobFree in mm/slab.h just
>   for the single callers being wrappers in mm/slob.c ]
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> ---
>  mm/slob.c | 34 +++++++++++++++++-----------------
>  1 file changed, 17 insertions(+), 17 deletions(-)
> 
> diff --git a/mm/slob.c b/mm/slob.c
> index d2d15e7f191c..d3512bcc3141 100644
> --- a/mm/slob.c
> +++ b/mm/slob.c

...

>  		/* Enough room on this page? */
> @@ -358,8 +358,8 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
>  		b = slob_new_pages(gfp & ~__GFP_ZERO, 0, node);
>  		if (!b)
>  			return NULL;
> -		sp = virt_to_page(b);
> -		__SetPageSlab(sp);
> +		sp = virt_to_slab(b);
> +		__SetPageSlab(slab_page(sp));

Hello Vlastimil.

I've tested this patch on my machine and it causes NULL pointer dereference.
that's because virt_to_slab returns NULL if folio_test_slab is false.
and __SetPageSlab is called with sp = NULL.

diff below fixed bug.

diff --git a/mm/slob.c b/mm/slob.c
index d3512bcc3141..cf669f03440f 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -358,8 +358,8 @@ static void *slob_alloc(size_t size, gfp_t gfp, int a
lign, int node,
                b = slob_new_pages(gfp & ~__GFP_ZERO, 0, node);
                if (!b)
                        return NULL;
+               __SetPageSlab(virt_to_page(b));
                sp = virt_to_slab(b);
-               __SetPageSlab(slab_page(sp));

                spin_lock_irqsave(&slob_lock, flags);
                sp->units = SLOB_UNITS(PAGE_SIZE);
 
 Thanks,
 Hyeonggon.

>  
>  		spin_lock_irqsave(&slob_lock, flags);
>  		sp->units = SLOB_UNITS(PAGE_SIZE);
> @@ -381,7 +381,7 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
>   */
>  static void slob_free(void *block, int size)
>  {
> -	struct page *sp;
> +	struct slab *sp;
>  	slob_t *prev, *next, *b = (slob_t *)block;
>  	slobidx_t units;
>  	unsigned long flags;
> @@ -391,7 +391,7 @@ static void slob_free(void *block, int size)
>  		return;
>  	BUG_ON(!size);
>  
> -	sp = virt_to_page(block);
> +	sp = virt_to_slab(block);
>  	units = SLOB_UNITS(size);
>  
>  	spin_lock_irqsave(&slob_lock, flags);
> @@ -401,8 +401,8 @@ static void slob_free(void *block, int size)
>  		if (slob_page_free(sp))
>  			clear_slob_page_free(sp);
>  		spin_unlock_irqrestore(&slob_lock, flags);
> -		__ClearPageSlab(sp);
> -		page_mapcount_reset(sp);
> +		__ClearPageSlab(slab_page(sp));
> +		page_mapcount_reset(slab_page(sp));
>  		slob_free_pages(b, 0);
>  		return;
>  	}
> -- 
> 2.33.1
> 
> 

Re: [PATCH v2 24/33] mm/slob: Convert SLOB to use struct slab

[Vlastimil Babka]

On 12/10/21 11:44, Hyeonggon Yoo wrote:
> On Wed, Dec 01, 2021 at 07:15:01PM +0100, Vlastimil Babka wrote:
>> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
>> 
>> Use struct slab throughout the slob allocator.
>> 
>> [ vbabka@suse.cz: don't introduce wrappers for PageSlobFree in mm/slab.h just
>>   for the single callers being wrappers in mm/slob.c ]
>> 
>> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
>> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
>> ---
>>  mm/slob.c | 34 +++++++++++++++++-----------------
>>  1 file changed, 17 insertions(+), 17 deletions(-)
>> 
>> diff --git a/mm/slob.c b/mm/slob.c
>> index d2d15e7f191c..d3512bcc3141 100644
>> --- a/mm/slob.c
>> +++ b/mm/slob.c
> 
> ...
> 
>>  		/* Enough room on this page? */
>> @@ -358,8 +358,8 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
>>  		b = slob_new_pages(gfp & ~__GFP_ZERO, 0, node);
>>  		if (!b)
>>  			return NULL;
>> -		sp = virt_to_page(b);
>> -		__SetPageSlab(sp);
>> +		sp = virt_to_slab(b);
>> +		__SetPageSlab(slab_page(sp));
> 
> Hello Vlastimil.
> 
> I've tested this patch on my machine and it causes NULL pointer dereference.
> that's because virt_to_slab returns NULL if folio_test_slab is false.
> and __SetPageSlab is called with sp = NULL.

Oops, thanks for catching this.

> diff below fixed bug.

Changed it to use folio and will push an updated branch
slab-struct_slab-v3r2

Thanks!

> diff --git a/mm/slob.c b/mm/slob.c
> index d3512bcc3141..cf669f03440f 100644
> --- a/mm/slob.c
> +++ b/mm/slob.c
> @@ -358,8 +358,8 @@ static void *slob_alloc(size_t size, gfp_t gfp, int a
> lign, int node,
>                 b = slob_new_pages(gfp & ~__GFP_ZERO, 0, node);
>                 if (!b)
>                         return NULL;
> +               __SetPageSlab(virt_to_page(b));
>                 sp = virt_to_slab(b);
> -               __SetPageSlab(slab_page(sp));
> 
>                 spin_lock_irqsave(&slob_lock, flags);
>                 sp->units = SLOB_UNITS(PAGE_SIZE);
>  
>  Thanks,
>  Hyeonggon.
> 
>>  
>>  		spin_lock_irqsave(&slob_lock, flags);
>>  		sp->units = SLOB_UNITS(PAGE_SIZE);
>> @@ -381,7 +381,7 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
>>   */
>>  static void slob_free(void *block, int size)
>>  {
>> -	struct page *sp;
>> +	struct slab *sp;
>>  	slob_t *prev, *next, *b = (slob_t *)block;
>>  	slobidx_t units;
>>  	unsigned long flags;
>> @@ -391,7 +391,7 @@ static void slob_free(void *block, int size)
>>  		return;
>>  	BUG_ON(!size);
>>  
>> -	sp = virt_to_page(block);
>> +	sp = virt_to_slab(block);
>>  	units = SLOB_UNITS(size);
>>  
>>  	spin_lock_irqsave(&slob_lock, flags);
>> @@ -401,8 +401,8 @@ static void slob_free(void *block, int size)
>>  		if (slob_page_free(sp))
>>  			clear_slob_page_free(sp);
>>  		spin_unlock_irqrestore(&slob_lock, flags);
>> -		__ClearPageSlab(sp);
>> -		page_mapcount_reset(sp);
>> +		__ClearPageSlab(slab_page(sp));
>> +		page_mapcount_reset(slab_page(sp));
>>  		slob_free_pages(b, 0);
>>  		return;
>>  	}
>> -- 
>> 2.33.1
>> 
>> 

Re: [PATCH v2 24/33] mm/slob: Convert SLOB to use struct slab

[Hyeonggon Yoo]

On Fri, Dec 10, 2021 at 12:44:32PM +0100, Vlastimil Babka wrote:
> On 12/10/21 11:44, Hyeonggon Yoo wrote:
> > On Wed, Dec 01, 2021 at 07:15:01PM +0100, Vlastimil Babka wrote:
> >> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> >> 
> >> Use struct slab throughout the slob allocator.
> >> 
> >> [ vbabka@suse.cz: don't introduce wrappers for PageSlobFree in mm/slab.h just
> >>   for the single callers being wrappers in mm/slob.c ]
> >> 
> >> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> >> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> >> ---
> >>  mm/slob.c | 34 +++++++++++++++++-----------------
> >>  1 file changed, 17 insertions(+), 17 deletions(-)
> >> 
> >> diff --git a/mm/slob.c b/mm/slob.c
> >> index d2d15e7f191c..d3512bcc3141 100644
> >> --- a/mm/slob.c
> >> +++ b/mm/slob.c
> > 
> > ...
> > 
> >>  		/* Enough room on this page? */
> >> @@ -358,8 +358,8 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
> >>  		b = slob_new_pages(gfp & ~__GFP_ZERO, 0, node);
> >>  		if (!b)
> >>  			return NULL;
> >> -		sp = virt_to_page(b);
> >> -		__SetPageSlab(sp);
> >> +		sp = virt_to_slab(b);
> >> +		__SetPageSlab(slab_page(sp));
> > 
> > Hello Vlastimil.
> > 
> > I've tested this patch on my machine and it causes NULL pointer dereference.
> > that's because virt_to_slab returns NULL if folio_test_slab is false.
> > and __SetPageSlab is called with sp = NULL.
> 
> Oops, thanks for catching this.
> 
> > diff below fixed bug.
> 
> Changed it to use folio and will push an updated branch
> slab-struct_slab-v3r2
> 
> Thanks!

Tested again on slab-struct_slab-v3r2 and everyting works fine!
And the code overall looks good to me.

Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

And below is not about this patch,
but what about something like this?

Because it's not necessary that page->_mapcount and
slab->units have same offset, so we can remove
(somewhat confusing) page_mapcount_reset function call.

I want to remove calling page_mapcount_reset also in
SLAB, but I have no idea. (maybe we can do that if we remove
SLAB colouring but that's going too far)

diff --git a/mm/slab.h b/mm/slab.h
index 90d7fceba470..dd0480149d38 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -50,8 +50,8 @@ struct slab {
        struct list_head slab_list;
        void * __unused_1;
        void *freelist;         /* first free block */
-       void * __unused_2;
-       int units;
+       long units;
+       unsigned int __unused_2;

 #else
 #error "Unexpected slab allocator configured"
diff --git a/mm/slob.c b/mm/slob.c
index 39b651b3e6e7..7b2d2c7d69cc 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -404,7 +404,6 @@ static void slob_free(void *block, int size)
                        clear_slob_page_free(sp);
                spin_unlock_irqrestore(&slob_lock, flags);
                __ClearPageSlab(slab_page(sp));
-               page_mapcount_reset(slab_page(sp));
                slob_free_pages(b, 0);
                return;
        }

> 
> > diff --git a/mm/slob.c b/mm/slob.c
> > index d3512bcc3141..cf669f03440f 100644
> > --- a/mm/slob.c
> > +++ b/mm/slob.c
> > @@ -358,8 +358,8 @@ static void *slob_alloc(size_t size, gfp_t gfp, int a
> > lign, int node,
> >                 b = slob_new_pages(gfp & ~__GFP_ZERO, 0, node);
> >                 if (!b)
> >                         return NULL;
> > +               __SetPageSlab(virt_to_page(b));
> >                 sp = virt_to_slab(b);
> > -               __SetPageSlab(slab_page(sp));
> > 
> >                 spin_lock_irqsave(&slob_lock, flags);
> >                 sp->units = SLOB_UNITS(PAGE_SIZE);
> >  
> >  Thanks,
> >  Hyeonggon.
> > 
> >>  
> >>  		spin_lock_irqsave(&slob_lock, flags);
> >>  		sp->units = SLOB_UNITS(PAGE_SIZE);
> >> @@ -381,7 +381,7 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
> >>   */
> >>  static void slob_free(void *block, int size)
> >>  {
> >> -	struct page *sp;
> >> +	struct slab *sp;
> >>  	slob_t *prev, *next, *b = (slob_t *)block;
> >>  	slobidx_t units;
> >>  	unsigned long flags;
> >> @@ -391,7 +391,7 @@ static void slob_free(void *block, int size)
> >>  		return;
> >>  	BUG_ON(!size);
> >>  
> >> -	sp = virt_to_page(block);
> >> +	sp = virt_to_slab(block);
> >>  	units = SLOB_UNITS(size);
> >>  
> >>  	spin_lock_irqsave(&slob_lock, flags);
> >> @@ -401,8 +401,8 @@ static void slob_free(void *block, int size)
> >>  		if (slob_page_free(sp))
> >>  			clear_slob_page_free(sp);
> >>  		spin_unlock_irqrestore(&slob_lock, flags);
> >> -		__ClearPageSlab(sp);
> >> -		page_mapcount_reset(sp);
> >> +		__ClearPageSlab(slab_page(sp));
> >> +		page_mapcount_reset(slab_page(sp));
> >>  		slob_free_pages(b, 0);
> >>  		return;
> >>  	}
> >> -- 
> >> 2.33.1
> >> 
> >> 
> 

Re: [PATCH v2 24/33] mm/slob: Convert SLOB to use struct slab

[Vlastimil Babka]

On 12/10/21 16:29, Hyeonggon Yoo wrote:
> On Fri, Dec 10, 2021 at 12:44:32PM +0100, Vlastimil Babka wrote:
>> On 12/10/21 11:44, Hyeonggon Yoo wrote:
>> > On Wed, Dec 01, 2021 at 07:15:01PM +0100, Vlastimil Babka wrote:
>> >> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
>> >> 
>> >> Use struct slab throughout the slob allocator.
>> >> 
>> >> [ vbabka@suse.cz: don't introduce wrappers for PageSlobFree in mm/slab.h just
>> >>   for the single callers being wrappers in mm/slob.c ]
>> >> 
>> >> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
>> >> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
>> >> ---
>> >>  mm/slob.c | 34 +++++++++++++++++-----------------
>> >>  1 file changed, 17 insertions(+), 17 deletions(-)
>> >> 
>> >> diff --git a/mm/slob.c b/mm/slob.c
>> >> index d2d15e7f191c..d3512bcc3141 100644
>> >> --- a/mm/slob.c
>> >> +++ b/mm/slob.c
>> > 
>> > ...
>> > 
>> >>  		/* Enough room on this page? */
>> >> @@ -358,8 +358,8 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
>> >>  		b = slob_new_pages(gfp & ~__GFP_ZERO, 0, node);
>> >>  		if (!b)
>> >>  			return NULL;
>> >> -		sp = virt_to_page(b);
>> >> -		__SetPageSlab(sp);
>> >> +		sp = virt_to_slab(b);
>> >> +		__SetPageSlab(slab_page(sp));
>> > 
>> > Hello Vlastimil.
>> > 
>> > I've tested this patch on my machine and it causes NULL pointer dereference.
>> > that's because virt_to_slab returns NULL if folio_test_slab is false.
>> > and __SetPageSlab is called with sp = NULL.
>> 
>> Oops, thanks for catching this.
>> 
>> > diff below fixed bug.
>> 
>> Changed it to use folio and will push an updated branch
>> slab-struct_slab-v3r2
>> 
>> Thanks!
> 
> Tested again on slab-struct_slab-v3r2 and everyting works fine!
> And the code overall looks good to me.
> 
> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

Thanks!

> And below is not about this patch,
> but what about something like this?
> 
> Because it's not necessary that page->_mapcount and
> slab->units have same offset, so we can remove
> (somewhat confusing) page_mapcount_reset function call.

Yeah this could be done as new patch on top of 21/33. I wouldn't squash it
there so that it remains just a split without functional change.

> I want to remove calling page_mapcount_reset also in
> SLAB, but I have no idea. (maybe we can do that if we remove
> SLAB colouring but that's going too far)
> 
> diff --git a/mm/slab.h b/mm/slab.h
> index 90d7fceba470..dd0480149d38 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -50,8 +50,8 @@ struct slab {
>         struct list_head slab_list;
>         void * __unused_1;
>         void *freelist;         /* first free block */
> -       void * __unused_2;
> -       int units;
> +       long units;
> +       unsigned int __unused_2;
> 
>  #else
>  #error "Unexpected slab allocator configured"
> diff --git a/mm/slob.c b/mm/slob.c
> index 39b651b3e6e7..7b2d2c7d69cc 100644
> --- a/mm/slob.c
> +++ b/mm/slob.c
> @@ -404,7 +404,6 @@ static void slob_free(void *block, int size)
>                         clear_slob_page_free(sp);
>                 spin_unlock_irqrestore(&slob_lock, flags);
>                 __ClearPageSlab(slab_page(sp));
> -               page_mapcount_reset(slab_page(sp));
>                 slob_free_pages(b, 0);
>                 return;
>         }
> 
>> 
>> > diff --git a/mm/slob.c b/mm/slob.c
>> > index d3512bcc3141..cf669f03440f 100644
>> > --- a/mm/slob.c
>> > +++ b/mm/slob.c
>> > @@ -358,8 +358,8 @@ static void *slob_alloc(size_t size, gfp_t gfp, int a
>> > lign, int node,
>> >                 b = slob_new_pages(gfp & ~__GFP_ZERO, 0, node);
>> >                 if (!b)
>> >                         return NULL;
>> > +               __SetPageSlab(virt_to_page(b));
>> >                 sp = virt_to_slab(b);
>> > -               __SetPageSlab(slab_page(sp));
>> > 
>> >                 spin_lock_irqsave(&slob_lock, flags);
>> >                 sp->units = SLOB_UNITS(PAGE_SIZE);
>> >  
>> >  Thanks,
>> >  Hyeonggon.
>> > 
>> >>  
>> >>  		spin_lock_irqsave(&slob_lock, flags);
>> >>  		sp->units = SLOB_UNITS(PAGE_SIZE);
>> >> @@ -381,7 +381,7 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
>> >>   */
>> >>  static void slob_free(void *block, int size)
>> >>  {
>> >> -	struct page *sp;
>> >> +	struct slab *sp;
>> >>  	slob_t *prev, *next, *b = (slob_t *)block;
>> >>  	slobidx_t units;
>> >>  	unsigned long flags;
>> >> @@ -391,7 +391,7 @@ static void slob_free(void *block, int size)
>> >>  		return;
>> >>  	BUG_ON(!size);
>> >>  
>> >> -	sp = virt_to_page(block);
>> >> +	sp = virt_to_slab(block);
>> >>  	units = SLOB_UNITS(size);
>> >>  
>> >>  	spin_lock_irqsave(&slob_lock, flags);
>> >> @@ -401,8 +401,8 @@ static void slob_free(void *block, int size)
>> >>  		if (slob_page_free(sp))
>> >>  			clear_slob_page_free(sp);
>> >>  		spin_unlock_irqrestore(&slob_lock, flags);
>> >> -		__ClearPageSlab(sp);
>> >> -		page_mapcount_reset(sp);
>> >> +		__ClearPageSlab(slab_page(sp));
>> >> +		page_mapcount_reset(slab_page(sp));
>> >>  		slob_free_pages(b, 0);
>> >>  		return;
>> >>  	}
>> >> -- 
>> >> 2.33.1
>> >> 
>> >> 
>> 

Re: [PATCH v2 24/33] mm/slob: Convert SLOB to use struct slab

[Hyeonggon Yoo]

On Fri, Dec 10, 2021 at 07:09:56PM +0100, Vlastimil Babka wrote:
> On 12/10/21 16:29, Hyeonggon Yoo wrote:
> > On Fri, Dec 10, 2021 at 12:44:32PM +0100, Vlastimil Babka wrote:
> >> On 12/10/21 11:44, Hyeonggon Yoo wrote:
> >> > On Wed, Dec 01, 2021 at 07:15:01PM +0100, Vlastimil Babka wrote:
> >> >> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> >> >> 
> >> >> Use struct slab throughout the slob allocator.
> >> >> 
> >> >> [ vbabka@suse.cz: don't introduce wrappers for PageSlobFree in mm/slab.h just
> >> >>   for the single callers being wrappers in mm/slob.c ]
> >> >> 
> >> >> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> >> >> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> >> >> ---
> >> >>  mm/slob.c | 34 +++++++++++++++++-----------------
> >> >>  1 file changed, 17 insertions(+), 17 deletions(-)
> >> >> 
> >> >> diff --git a/mm/slob.c b/mm/slob.c
> >> >> index d2d15e7f191c..d3512bcc3141 100644
> >> >> --- a/mm/slob.c
> >> >> +++ b/mm/slob.c
> >> > 
> >> > ...
> >> > 
> >> >>  		/* Enough room on this page? */
> >> >> @@ -358,8 +358,8 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
> >> >>  		b = slob_new_pages(gfp & ~__GFP_ZERO, 0, node);
> >> >>  		if (!b)
> >> >>  			return NULL;
> >> >> -		sp = virt_to_page(b);
> >> >> -		__SetPageSlab(sp);
> >> >> +		sp = virt_to_slab(b);
> >> >> +		__SetPageSlab(slab_page(sp));
> >> > 
> >> > Hello Vlastimil.
> >> > 
> >> > I've tested this patch on my machine and it causes NULL pointer dereference.
> >> > that's because virt_to_slab returns NULL if folio_test_slab is false.
> >> > and __SetPageSlab is called with sp = NULL.
> >> 
> >> Oops, thanks for catching this.
> >> 
> >> > diff below fixed bug.
> >> 
> >> Changed it to use folio and will push an updated branch
> >> slab-struct_slab-v3r2
> >> 
> >> Thanks!
> > 
> > Tested again on slab-struct_slab-v3r2 and everyting works fine!
> > And the code overall looks good to me.
> > 
> > Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> 
> Thanks!
>

You're welcome! :)

> > And below is not about this patch,
> > but what about something like this?
> > 
> > Because it's not necessary that page->_mapcount and
> > slab->units have same offset, so we can remove
> > (somewhat confusing) page_mapcount_reset function call.
> 
> Yeah this could be done as new patch on top of 21/33. I wouldn't squash it
> there so that it remains just a split without functional change.
>

Yeah, It is better to be done as separate patch.
I'll send it as a patch.

Thanks,
Hyeonggon

> > I want to remove calling page_mapcount_reset also in
> > SLAB, but I have no idea. (maybe we can do that if we remove
> > SLAB colouring but that's going too far)
> > 
> > diff --git a/mm/slab.h b/mm/slab.h
> > index 90d7fceba470..dd0480149d38 100644
> > --- a/mm/slab.h
> > +++ b/mm/slab.h
> > @@ -50,8 +50,8 @@ struct slab {
> >         struct list_head slab_list;
> >         void * __unused_1;
> >         void *freelist;         /* first free block */
> > -       void * __unused_2;
> > -       int units;
> > +       long units;
> > +       unsigned int __unused_2;
> > 
> >  #else
> >  #error "Unexpected slab allocator configured"
> > diff --git a/mm/slob.c b/mm/slob.c
> > index 39b651b3e6e7..7b2d2c7d69cc 100644
> > --- a/mm/slob.c
> > +++ b/mm/slob.c
> > @@ -404,7 +404,6 @@ static void slob_free(void *block, int size)
> >                         clear_slob_page_free(sp);
> >                 spin_unlock_irqrestore(&slob_lock, flags);
> >                 __ClearPageSlab(slab_page(sp));
> > -               page_mapcount_reset(slab_page(sp));
> >                 slob_free_pages(b, 0);
> >                 return;
> >         }
> > 
> >> 
> >> > diff --git a/mm/slob.c b/mm/slob.c
> >> > index d3512bcc3141..cf669f03440f 100644
> >> > --- a/mm/slob.c
> >> > +++ b/mm/slob.c
> >> > @@ -358,8 +358,8 @@ static void *slob_alloc(size_t size, gfp_t gfp, int a
> >> > lign, int node,
> >> >                 b = slob_new_pages(gfp & ~__GFP_ZERO, 0, node);
> >> >                 if (!b)
> >> >                         return NULL;
> >> > +               __SetPageSlab(virt_to_page(b));
> >> >                 sp = virt_to_slab(b);
> >> > -               __SetPageSlab(slab_page(sp));
> >> > 
> >> >                 spin_lock_irqsave(&slob_lock, flags);
> >> >                 sp->units = SLOB_UNITS(PAGE_SIZE);
> >> >  
> >> >  Thanks,
> >> >  Hyeonggon.
> >> > 
> >> >>  
> >> >>  		spin_lock_irqsave(&slob_lock, flags);
> >> >>  		sp->units = SLOB_UNITS(PAGE_SIZE);
> >> >> @@ -381,7 +381,7 @@ static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
> >> >>   */
> >> >>  static void slob_free(void *block, int size)
> >> >>  {
> >> >> -	struct page *sp;
> >> >> +	struct slab *sp;
> >> >>  	slob_t *prev, *next, *b = (slob_t *)block;
> >> >>  	slobidx_t units;
> >> >>  	unsigned long flags;
> >> >> @@ -391,7 +391,7 @@ static void slob_free(void *block, int size)
> >> >>  		return;
> >> >>  	BUG_ON(!size);
> >> >>  
> >> >> -	sp = virt_to_page(block);
> >> >> +	sp = virt_to_slab(block);
> >> >>  	units = SLOB_UNITS(size);
> >> >>  
> >> >>  	spin_lock_irqsave(&slob_lock, flags);
> >> >> @@ -401,8 +401,8 @@ static void slob_free(void *block, int size)
> >> >>  		if (slob_page_free(sp))
> >> >>  			clear_slob_page_free(sp);
> >> >>  		spin_unlock_irqrestore(&slob_lock, flags);
> >> >> -		__ClearPageSlab(sp);
> >> >> -		page_mapcount_reset(sp);
> >> >> +		__ClearPageSlab(slab_page(sp));
> >> >> +		page_mapcount_reset(slab_page(sp));
> >> >>  		slob_free_pages(b, 0);
> >> >>  		return;
> >> >>  	}
> >> >> -- 
> >> >> 2.33.1
> >> >> 
> >> >> 
> >> 
> 

[PATCH v2 25/33] mm/kasan: Convert to struct folio and struct slab

[Vlastimil Babka]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

KASAN accesses some slab related struct page fields so we need to convert it
to struct slab. Some places are a bit simplified thanks to kasan_addr_to_slab()
encapsulating the PageSlab flag check through virt_to_slab().
When resolving object address to either a real slab or a large kmalloc, use
struct folio as the intermediate type for testing the slab flag to avoid
unnecessary implicit compound_head().

[ vbabka@suse.cz: use struct folio, adjust to differences in previous patches ]

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: <kasan-dev@googlegroups.com>
---
 include/linux/kasan.h  |  9 +++++----
 mm/kasan/common.c      | 23 +++++++++++++----------
 mm/kasan/generic.c     |  8 ++++----
 mm/kasan/kasan.h       |  1 +
 mm/kasan/quarantine.c  |  2 +-
 mm/kasan/report.c      | 13 +++++++++++--
 mm/kasan/report_tags.c | 10 +++++-----
 mm/slab.c              |  2 +-
 mm/slub.c              |  2 +-
 9 files changed, 42 insertions(+), 28 deletions(-)

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index d8783b682669..fb78108d694e 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -9,6 +9,7 @@
 
 struct kmem_cache;
 struct page;
+struct slab;
 struct vm_struct;
 struct task_struct;
 
@@ -193,11 +194,11 @@ static __always_inline size_t kasan_metadata_size(struct kmem_cache *cache)
 	return 0;
 }
 
-void __kasan_poison_slab(struct page *page);
-static __always_inline void kasan_poison_slab(struct page *page)
+void __kasan_poison_slab(struct slab *slab);
+static __always_inline void kasan_poison_slab(struct slab *slab)
 {
 	if (kasan_enabled())
-		__kasan_poison_slab(page);
+		__kasan_poison_slab(slab);
 }
 
 void __kasan_unpoison_object_data(struct kmem_cache *cache, void *object);
@@ -322,7 +323,7 @@ static inline void kasan_cache_create(struct kmem_cache *cache,
 				      slab_flags_t *flags) {}
 static inline void kasan_cache_create_kmalloc(struct kmem_cache *cache) {}
 static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
-static inline void kasan_poison_slab(struct page *page) {}
+static inline void kasan_poison_slab(struct slab *slab) {}
 static inline void kasan_unpoison_object_data(struct kmem_cache *cache,
 					void *object) {}
 static inline void kasan_poison_object_data(struct kmem_cache *cache,
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 6a1cd2d38bff..7c06db78a76c 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -247,8 +247,9 @@ struct kasan_free_meta *kasan_get_free_meta(struct kmem_cache *cache,
 }
 #endif
 
-void __kasan_poison_slab(struct page *page)
+void __kasan_poison_slab(struct slab *slab)
 {
+	struct page *page = slab_page(slab);
 	unsigned long i;
 
 	for (i = 0; i < compound_nr(page); i++)
@@ -401,9 +402,9 @@ void __kasan_kfree_large(void *ptr, unsigned long ip)
 
 void __kasan_slab_free_mempool(void *ptr, unsigned long ip)
 {
-	struct page *page;
+	struct folio *folio;
 
-	page = virt_to_head_page(ptr);
+	folio = virt_to_folio(ptr);
 
 	/*
 	 * Even though this function is only called for kmem_cache_alloc and
@@ -411,12 +412,14 @@ void __kasan_slab_free_mempool(void *ptr, unsigned long ip)
 	 * !PageSlab() when the size provided to kmalloc is larger than
 	 * KMALLOC_MAX_SIZE, and kmalloc falls back onto page_alloc.
 	 */
-	if (unlikely(!PageSlab(page))) {
+	if (unlikely(!folio_test_slab(folio))) {
 		if (____kasan_kfree_large(ptr, ip))
 			return;
-		kasan_poison(ptr, page_size(page), KASAN_FREE_PAGE, false);
+		kasan_poison(ptr, folio_size(folio), KASAN_FREE_PAGE, false);
 	} else {
-		____kasan_slab_free(page->slab_cache, ptr, ip, false, false);
+		struct slab *slab = folio_slab(folio);
+
+		____kasan_slab_free(slab->slab_cache, ptr, ip, false, false);
 	}
 }
 
@@ -560,7 +563,7 @@ void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size,
 
 void * __must_check __kasan_krealloc(const void *object, size_t size, gfp_t flags)
 {
-	struct page *page;
+	struct slab *slab;
 
 	if (unlikely(object == ZERO_SIZE_PTR))
 		return (void *)object;
@@ -572,13 +575,13 @@ void * __must_check __kasan_krealloc(const void *object, size_t size, gfp_t flag
 	 */
 	kasan_unpoison(object, size, false);
 
-	page = virt_to_head_page(object);
+	slab = virt_to_slab(object);
 
 	/* Piggy-back on kmalloc() instrumentation to poison the redzone. */
-	if (unlikely(!PageSlab(page)))
+	if (unlikely(!slab))
 		return __kasan_kmalloc_large(object, size, flags);
 	else
-		return ____kasan_kmalloc(page->slab_cache, object, size, flags);
+		return ____kasan_kmalloc(slab->slab_cache, object, size, flags);
 }
 
 bool __kasan_check_byte(const void *address, unsigned long ip)
diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
index 5d0b79416c4e..a25ad4090615 100644
--- a/mm/kasan/generic.c
+++ b/mm/kasan/generic.c
@@ -330,16 +330,16 @@ DEFINE_ASAN_SET_SHADOW(f8);
 
 static void __kasan_record_aux_stack(void *addr, bool can_alloc)
 {
-	struct page *page = kasan_addr_to_page(addr);
+	struct slab *slab = kasan_addr_to_slab(addr);
 	struct kmem_cache *cache;
 	struct kasan_alloc_meta *alloc_meta;
 	void *object;
 
-	if (is_kfence_address(addr) || !(page && PageSlab(page)))
+	if (is_kfence_address(addr) || !slab)
 		return;
 
-	cache = page->slab_cache;
-	object = nearest_obj(cache, page_slab(page), addr);
+	cache = slab->slab_cache;
+	object = nearest_obj(cache, slab, addr);
 	alloc_meta = kasan_get_alloc_meta(cache, object);
 	if (!alloc_meta)
 		return;
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index aebd8df86a1f..c17fa8d26ffe 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -265,6 +265,7 @@ bool kasan_report(unsigned long addr, size_t size,
 void kasan_report_invalid_free(void *object, unsigned long ip);
 
 struct page *kasan_addr_to_page(const void *addr);
+struct slab *kasan_addr_to_slab(const void *addr);
 
 depot_stack_handle_t kasan_save_stack(gfp_t flags, bool can_alloc);
 void kasan_set_track(struct kasan_track *track, gfp_t flags);
diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
index d8ccff4c1275..587da8995f2d 100644
--- a/mm/kasan/quarantine.c
+++ b/mm/kasan/quarantine.c
@@ -117,7 +117,7 @@ static unsigned long quarantine_batch_size;
 
 static struct kmem_cache *qlink_to_cache(struct qlist_node *qlink)
 {
-	return virt_to_head_page(qlink)->slab_cache;
+	return virt_to_slab(qlink)->slab_cache;
 }
 
 static void *qlink_to_object(struct qlist_node *qlink, struct kmem_cache *cache)
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index e00999dc6499..3ad9624dcc56 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -150,6 +150,14 @@ struct page *kasan_addr_to_page(const void *addr)
 	return NULL;
 }
 
+struct slab *kasan_addr_to_slab(const void *addr)
+{
+	if ((addr >= (void *)PAGE_OFFSET) &&
+			(addr < high_memory))
+		return virt_to_slab(addr);
+	return NULL;
+}
+
 static void describe_object_addr(struct kmem_cache *cache, void *object,
 				const void *addr)
 {
@@ -248,8 +256,9 @@ static void print_address_description(void *addr, u8 tag)
 	pr_err("\n");
 
 	if (page && PageSlab(page)) {
-		struct kmem_cache *cache = page->slab_cache;
-		void *object = nearest_obj(cache, page_slab(page),	addr);
+		struct slab *slab = page_slab(page);
+		struct kmem_cache *cache = slab->slab_cache;
+		void *object = nearest_obj(cache, slab,	addr);
 
 		describe_object(cache, object, addr, tag);
 	}
diff --git a/mm/kasan/report_tags.c b/mm/kasan/report_tags.c
index 06c21dd77493..1b41de88c53e 100644
--- a/mm/kasan/report_tags.c
+++ b/mm/kasan/report_tags.c
@@ -12,7 +12,7 @@ const char *kasan_get_bug_type(struct kasan_access_info *info)
 #ifdef CONFIG_KASAN_TAGS_IDENTIFY
 	struct kasan_alloc_meta *alloc_meta;
 	struct kmem_cache *cache;
-	struct page *page;
+	struct slab *slab;
 	const void *addr;
 	void *object;
 	u8 tag;
@@ -20,10 +20,10 @@ const char *kasan_get_bug_type(struct kasan_access_info *info)
 
 	tag = get_tag(info->access_addr);
 	addr = kasan_reset_tag(info->access_addr);
-	page = kasan_addr_to_page(addr);
-	if (page && PageSlab(page)) {
-		cache = page->slab_cache;
-		object = nearest_obj(cache, page_slab(page), (void *)addr);
+	slab = kasan_addr_to_slab(addr);
+	if (slab) {
+		cache = slab->slab_cache;
+		object = nearest_obj(cache, slab, (void *)addr);
 		alloc_meta = kasan_get_alloc_meta(cache, object);
 
 		if (alloc_meta) {
diff --git a/mm/slab.c b/mm/slab.c
index 785fffd527fe..fed55fa1b7d0 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2605,7 +2605,7 @@ static struct slab *cache_grow_begin(struct kmem_cache *cachep,
 	 * page_address() in the latter returns a non-tagged pointer,
 	 * as it should be for slab pages.
 	 */
-	kasan_poison_slab(slab_page(slab));
+	kasan_poison_slab(slab);
 
 	/* Get slab management. */
 	freelist = alloc_slabmgmt(cachep, slab, offset,
diff --git a/mm/slub.c b/mm/slub.c
index 61aaaa662c5e..58f0d499a293 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1961,7 +1961,7 @@ static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 
 	slab->slab_cache = s;
 
-	kasan_poison_slab(slab_page(slab));
+	kasan_poison_slab(slab);
 
 	start = slab_address(slab);
 
-- 
2.33.1

Re: [PATCH v2 25/33] mm/kasan: Convert to struct folio and struct slab

[Andrey Konovalov]

On Wed, Dec 1, 2021 at 7:15 PM Vlastimil Babka <vbabka@suse.cz> wrote:
>
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
>
> KASAN accesses some slab related struct page fields so we need to convert it
> to struct slab. Some places are a bit simplified thanks to kasan_addr_to_slab()
> encapsulating the PageSlab flag check through virt_to_slab().
> When resolving object address to either a real slab or a large kmalloc, use
> struct folio as the intermediate type for testing the slab flag to avoid
> unnecessary implicit compound_head().
>
> [ vbabka@suse.cz: use struct folio, adjust to differences in previous patches ]
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
> Cc: Alexander Potapenko <glider@google.com>
> Cc: Andrey Konovalov <andreyknvl@gmail.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Cc: <kasan-dev@googlegroups.com>
> ---
>  include/linux/kasan.h  |  9 +++++----
>  mm/kasan/common.c      | 23 +++++++++++++----------
>  mm/kasan/generic.c     |  8 ++++----
>  mm/kasan/kasan.h       |  1 +
>  mm/kasan/quarantine.c  |  2 +-
>  mm/kasan/report.c      | 13 +++++++++++--
>  mm/kasan/report_tags.c | 10 +++++-----
>  mm/slab.c              |  2 +-
>  mm/slub.c              |  2 +-
>  9 files changed, 42 insertions(+), 28 deletions(-)
>
> diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> index d8783b682669..fb78108d694e 100644
> --- a/include/linux/kasan.h
> +++ b/include/linux/kasan.h
> @@ -9,6 +9,7 @@
>
>  struct kmem_cache;
>  struct page;
> +struct slab;
>  struct vm_struct;
>  struct task_struct;
>
> @@ -193,11 +194,11 @@ static __always_inline size_t kasan_metadata_size(struct kmem_cache *cache)
>         return 0;
>  }
>
> -void __kasan_poison_slab(struct page *page);
> -static __always_inline void kasan_poison_slab(struct page *page)
> +void __kasan_poison_slab(struct slab *slab);
> +static __always_inline void kasan_poison_slab(struct slab *slab)
>  {
>         if (kasan_enabled())
> -               __kasan_poison_slab(page);
> +               __kasan_poison_slab(slab);
>  }
>
>  void __kasan_unpoison_object_data(struct kmem_cache *cache, void *object);
> @@ -322,7 +323,7 @@ static inline void kasan_cache_create(struct kmem_cache *cache,
>                                       slab_flags_t *flags) {}
>  static inline void kasan_cache_create_kmalloc(struct kmem_cache *cache) {}
>  static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
> -static inline void kasan_poison_slab(struct page *page) {}
> +static inline void kasan_poison_slab(struct slab *slab) {}
>  static inline void kasan_unpoison_object_data(struct kmem_cache *cache,
>                                         void *object) {}
>  static inline void kasan_poison_object_data(struct kmem_cache *cache,
> diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> index 6a1cd2d38bff..7c06db78a76c 100644
> --- a/mm/kasan/common.c
> +++ b/mm/kasan/common.c
> @@ -247,8 +247,9 @@ struct kasan_free_meta *kasan_get_free_meta(struct kmem_cache *cache,
>  }
>  #endif
>
> -void __kasan_poison_slab(struct page *page)
> +void __kasan_poison_slab(struct slab *slab)
>  {
> +       struct page *page = slab_page(slab);
>         unsigned long i;
>
>         for (i = 0; i < compound_nr(page); i++)
> @@ -401,9 +402,9 @@ void __kasan_kfree_large(void *ptr, unsigned long ip)
>
>  void __kasan_slab_free_mempool(void *ptr, unsigned long ip)
>  {
> -       struct page *page;
> +       struct folio *folio;
>
> -       page = virt_to_head_page(ptr);
> +       folio = virt_to_folio(ptr);
>
>         /*
>          * Even though this function is only called for kmem_cache_alloc and
> @@ -411,12 +412,14 @@ void __kasan_slab_free_mempool(void *ptr, unsigned long ip)
>          * !PageSlab() when the size provided to kmalloc is larger than
>          * KMALLOC_MAX_SIZE, and kmalloc falls back onto page_alloc.
>          */
> -       if (unlikely(!PageSlab(page))) {
> +       if (unlikely(!folio_test_slab(folio))) {
>                 if (____kasan_kfree_large(ptr, ip))
>                         return;
> -               kasan_poison(ptr, page_size(page), KASAN_FREE_PAGE, false);
> +               kasan_poison(ptr, folio_size(folio), KASAN_FREE_PAGE, false);
>         } else {
> -               ____kasan_slab_free(page->slab_cache, ptr, ip, false, false);
> +               struct slab *slab = folio_slab(folio);
> +
> +               ____kasan_slab_free(slab->slab_cache, ptr, ip, false, false);
>         }
>  }
>
> @@ -560,7 +563,7 @@ void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size,
>
>  void * __must_check __kasan_krealloc(const void *object, size_t size, gfp_t flags)
>  {
> -       struct page *page;
> +       struct slab *slab;
>
>         if (unlikely(object == ZERO_SIZE_PTR))
>                 return (void *)object;
> @@ -572,13 +575,13 @@ void * __must_check __kasan_krealloc(const void *object, size_t size, gfp_t flag
>          */
>         kasan_unpoison(object, size, false);
>
> -       page = virt_to_head_page(object);
> +       slab = virt_to_slab(object);
>
>         /* Piggy-back on kmalloc() instrumentation to poison the redzone. */
> -       if (unlikely(!PageSlab(page)))
> +       if (unlikely(!slab))
>                 return __kasan_kmalloc_large(object, size, flags);
>         else
> -               return ____kasan_kmalloc(page->slab_cache, object, size, flags);
> +               return ____kasan_kmalloc(slab->slab_cache, object, size, flags);
>  }
>
>  bool __kasan_check_byte(const void *address, unsigned long ip)
> diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
> index 5d0b79416c4e..a25ad4090615 100644
> --- a/mm/kasan/generic.c
> +++ b/mm/kasan/generic.c
> @@ -330,16 +330,16 @@ DEFINE_ASAN_SET_SHADOW(f8);
>
>  static void __kasan_record_aux_stack(void *addr, bool can_alloc)
>  {
> -       struct page *page = kasan_addr_to_page(addr);
> +       struct slab *slab = kasan_addr_to_slab(addr);
>         struct kmem_cache *cache;
>         struct kasan_alloc_meta *alloc_meta;
>         void *object;
>
> -       if (is_kfence_address(addr) || !(page && PageSlab(page)))
> +       if (is_kfence_address(addr) || !slab)
>                 return;
>
> -       cache = page->slab_cache;
> -       object = nearest_obj(cache, page_slab(page), addr);
> +       cache = slab->slab_cache;
> +       object = nearest_obj(cache, slab, addr);
>         alloc_meta = kasan_get_alloc_meta(cache, object);
>         if (!alloc_meta)
>                 return;
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index aebd8df86a1f..c17fa8d26ffe 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -265,6 +265,7 @@ bool kasan_report(unsigned long addr, size_t size,
>  void kasan_report_invalid_free(void *object, unsigned long ip);
>
>  struct page *kasan_addr_to_page(const void *addr);
> +struct slab *kasan_addr_to_slab(const void *addr);
>
>  depot_stack_handle_t kasan_save_stack(gfp_t flags, bool can_alloc);
>  void kasan_set_track(struct kasan_track *track, gfp_t flags);
> diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
> index d8ccff4c1275..587da8995f2d 100644
> --- a/mm/kasan/quarantine.c
> +++ b/mm/kasan/quarantine.c
> @@ -117,7 +117,7 @@ static unsigned long quarantine_batch_size;
>
>  static struct kmem_cache *qlink_to_cache(struct qlist_node *qlink)
>  {
> -       return virt_to_head_page(qlink)->slab_cache;
> +       return virt_to_slab(qlink)->slab_cache;
>  }
>
>  static void *qlink_to_object(struct qlist_node *qlink, struct kmem_cache *cache)
> diff --git a/mm/kasan/report.c b/mm/kasan/report.c
> index e00999dc6499..3ad9624dcc56 100644
> --- a/mm/kasan/report.c
> +++ b/mm/kasan/report.c
> @@ -150,6 +150,14 @@ struct page *kasan_addr_to_page(const void *addr)
>         return NULL;
>  }
>
> +struct slab *kasan_addr_to_slab(const void *addr)
> +{
> +       if ((addr >= (void *)PAGE_OFFSET) &&
> +                       (addr < high_memory))
> +               return virt_to_slab(addr);
> +       return NULL;
> +}
> +
>  static void describe_object_addr(struct kmem_cache *cache, void *object,
>                                 const void *addr)
>  {
> @@ -248,8 +256,9 @@ static void print_address_description(void *addr, u8 tag)
>         pr_err("\n");
>
>         if (page && PageSlab(page)) {
> -               struct kmem_cache *cache = page->slab_cache;
> -               void *object = nearest_obj(cache, page_slab(page),      addr);
> +               struct slab *slab = page_slab(page);
> +               struct kmem_cache *cache = slab->slab_cache;
> +               void *object = nearest_obj(cache, slab, addr);
>
>                 describe_object(cache, object, addr, tag);
>         }
> diff --git a/mm/kasan/report_tags.c b/mm/kasan/report_tags.c
> index 06c21dd77493..1b41de88c53e 100644
> --- a/mm/kasan/report_tags.c
> +++ b/mm/kasan/report_tags.c
> @@ -12,7 +12,7 @@ const char *kasan_get_bug_type(struct kasan_access_info *info)
>  #ifdef CONFIG_KASAN_TAGS_IDENTIFY
>         struct kasan_alloc_meta *alloc_meta;
>         struct kmem_cache *cache;
> -       struct page *page;
> +       struct slab *slab;
>         const void *addr;
>         void *object;
>         u8 tag;
> @@ -20,10 +20,10 @@ const char *kasan_get_bug_type(struct kasan_access_info *info)
>
>         tag = get_tag(info->access_addr);
>         addr = kasan_reset_tag(info->access_addr);
> -       page = kasan_addr_to_page(addr);
> -       if (page && PageSlab(page)) {
> -               cache = page->slab_cache;
> -               object = nearest_obj(cache, page_slab(page), (void *)addr);
> +       slab = kasan_addr_to_slab(addr);
> +       if (slab) {
> +               cache = slab->slab_cache;
> +               object = nearest_obj(cache, slab, (void *)addr);
>                 alloc_meta = kasan_get_alloc_meta(cache, object);
>
>                 if (alloc_meta) {
> diff --git a/mm/slab.c b/mm/slab.c
> index 785fffd527fe..fed55fa1b7d0 100644
> --- a/mm/slab.c
> +++ b/mm/slab.c
> @@ -2605,7 +2605,7 @@ static struct slab *cache_grow_begin(struct kmem_cache *cachep,
>          * page_address() in the latter returns a non-tagged pointer,
>          * as it should be for slab pages.
>          */
> -       kasan_poison_slab(slab_page(slab));
> +       kasan_poison_slab(slab);
>
>         /* Get slab management. */
>         freelist = alloc_slabmgmt(cachep, slab, offset,
> diff --git a/mm/slub.c b/mm/slub.c
> index 61aaaa662c5e..58f0d499a293 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -1961,7 +1961,7 @@ static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
>
>         slab->slab_cache = s;
>
> -       kasan_poison_slab(slab_page(slab));
> +       kasan_poison_slab(slab);
>
>         start = slab_address(slab);
>
> --
> 2.33.1
>

Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>

Great job with the overall struct page refactoring!

Thanks!

[PATCH v2 26/33] mm/kfence: Convert kfence_guarded_alloc() to struct slab

[Vlastimil Babka]

The function sets some fields that are being moved from struct page to struct
slab so it needs to be converted.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: <kasan-dev@googlegroups.com>
---
 mm/kfence/core.c        | 12 ++++++------
 mm/kfence/kfence_test.c |  6 +++---
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 09945784df9e..4eb60cf5ff8b 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -360,7 +360,7 @@ static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t g
 {
 	struct kfence_metadata *meta = NULL;
 	unsigned long flags;
-	struct page *page;
+	struct slab *slab;
 	void *addr;
 
 	/* Try to obtain a free object. */
@@ -424,13 +424,13 @@ static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t g
 
 	alloc_covered_add(alloc_stack_hash, 1);
 
-	/* Set required struct page fields. */
-	page = virt_to_page(meta->addr);
-	page->slab_cache = cache;
+	/* Set required slab fields. */
+	slab = virt_to_slab((void *)meta->addr);
+	slab->slab_cache = cache;
 	if (IS_ENABLED(CONFIG_SLUB))
-		page->objects = 1;
+		slab->objects = 1;
 	if (IS_ENABLED(CONFIG_SLAB))
-		page->s_mem = addr;
+		slab->s_mem = addr;
 
 	/* Memory initialization. */
 	for_each_canary(meta, set_canary_byte);
diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c
index f7276711d7b9..a22b1af85577 100644
--- a/mm/kfence/kfence_test.c
+++ b/mm/kfence/kfence_test.c
@@ -282,7 +282,7 @@ static void *test_alloc(struct kunit *test, size_t size, gfp_t gfp, enum allocat
 			alloc = kmalloc(size, gfp);
 
 		if (is_kfence_address(alloc)) {
-			struct page *page = virt_to_head_page(alloc);
+			struct slab *slab = virt_to_slab(alloc);
 			struct kmem_cache *s = test_cache ?:
 					kmalloc_caches[kmalloc_type(GFP_KERNEL)][__kmalloc_index(size, false)];
 
@@ -291,8 +291,8 @@ static void *test_alloc(struct kunit *test, size_t size, gfp_t gfp, enum allocat
 			 * even for KFENCE objects; these are required so that
 			 * memcg accounting works correctly.
 			 */
-			KUNIT_EXPECT_EQ(test, obj_to_index(s, page_slab(page), alloc), 0U);
-			KUNIT_EXPECT_EQ(test, objs_per_slab(s, page_slab(page)), 1);
+			KUNIT_EXPECT_EQ(test, obj_to_index(s, slab, alloc), 0U);
+			KUNIT_EXPECT_EQ(test, objs_per_slab(s, slab), 1);
 
 			if (policy == ALLOCATE_ANY)
 				return alloc;
-- 
2.33.1

[PATCH v2 27/33] zsmalloc: Stop using slab fields in struct page

[Vlastimil Babka]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

The ->freelist and ->units members of struct page are for the use of slab
only.  I'm not particularly familiar with zsmalloc, so generate the same
code by using page->index to store 'page' (page->index and page->freelist
are at the same offset in struct page).  This should be cleaned up
properly at some point by somebody who is familiar with zsmalloc.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
---
 mm/zsmalloc.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index b897ce3b399a..0d3b65939016 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -17,10 +17,10 @@
  *
  * Usage of struct page fields:
  *	page->private: points to zspage
- *	page->freelist(index): links together all component pages of a zspage
+ *	page->index: links together all component pages of a zspage
  *		For the huge page, this is always 0, so we use this field
  *		to store handle.
- *	page->units: first object offset in a subpage of zspage
+ *	page->page_type: first object offset in a subpage of zspage
  *
  * Usage of struct page flags:
  *	PG_private: identifies the first component page
@@ -489,12 +489,12 @@ static inline struct page *get_first_page(struct zspage *zspage)
 
 static inline int get_first_obj_offset(struct page *page)
 {
-	return page->units;
+	return page->page_type;
 }
 
 static inline void set_first_obj_offset(struct page *page, int offset)
 {
-	page->units = offset;
+	page->page_type = offset;
 }
 
 static inline unsigned int get_freeobj(struct zspage *zspage)
@@ -827,7 +827,7 @@ static struct page *get_next_page(struct page *page)
 	if (unlikely(PageHugeObject(page)))
 		return NULL;
 
-	return page->freelist;
+	return (struct page *)page->index;
 }
 
 /**
@@ -901,7 +901,7 @@ static void reset_page(struct page *page)
 	set_page_private(page, 0);
 	page_mapcount_reset(page);
 	ClearPageHugeObject(page);
-	page->freelist = NULL;
+	page->index = 0;
 }
 
 static int trylock_zspage(struct zspage *zspage)
@@ -1027,7 +1027,7 @@ static void create_page_chain(struct size_class *class, struct zspage *zspage,
 
 	/*
 	 * Allocate individual pages and link them together as:
-	 * 1. all pages are linked together using page->freelist
+	 * 1. all pages are linked together using page->index
 	 * 2. each sub-page point to zspage using page->private
 	 *
 	 * we set PG_private to identify the first page (i.e. no other sub-page
@@ -1036,7 +1036,7 @@ static void create_page_chain(struct size_class *class, struct zspage *zspage,
 	for (i = 0; i < nr_pages; i++) {
 		page = pages[i];
 		set_page_private(page, (unsigned long)zspage);
-		page->freelist = NULL;
+		page->index = 0;
 		if (i == 0) {
 			zspage->first_page = page;
 			SetPagePrivate(page);
@@ -1044,7 +1044,7 @@ static void create_page_chain(struct size_class *class, struct zspage *zspage,
 					class->pages_per_zspage == 1))
 				SetPageHugeObject(page);
 		} else {
-			prev_page->freelist = page;
+			prev_page->index = (unsigned long)page;
 		}
 		prev_page = page;
 	}
-- 
2.33.1

Re: [PATCH v2 27/33] zsmalloc: Stop using slab fields in struct page

[Minchan Kim]

On Wed, Dec 01, 2021 at 07:15:04PM +0100, Vlastimil Babka wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> The ->freelist and ->units members of struct page are for the use of slab
> only.  I'm not particularly familiar with zsmalloc, so generate the same
> code by using page->index to store 'page' (page->index and page->freelist
> are at the same offset in struct page).  This should be cleaned up
> properly at some point by somebody who is familiar with zsmalloc.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Minchan Kim <minchan@kernel.org>

Re: [PATCH v2 27/33] zsmalloc: Stop using slab fields in struct page

[Johannes Weiner]

On Wed, Dec 01, 2021 at 07:15:04PM +0100, Vlastimil Babka wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> The ->freelist and ->units members of struct page are for the use of slab
> only.  I'm not particularly familiar with zsmalloc, so generate the same
> code by using page->index to store 'page' (page->index and page->freelist
> are at the same offset in struct page).  This should be cleaned up
> properly at some point by somebody who is familiar with zsmalloc.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> Cc: Minchan Kim <minchan@kernel.org>
> Cc: Nitin Gupta <ngupta@vflare.org>
> Cc: Sergey Senozhatsky <senozhatsky@chromium.org>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

[PATCH v2 28/33] bootmem: Use page->index instead of page->freelist

[Vlastimil Babka]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

page->freelist is for the use of slab.  Using page->index is the same
set of bits as page->freelist, and by using an integer instead of a
pointer, we can avoid casts.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: <x86@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
---
 arch/x86/mm/init_64.c        | 2 +-
 include/linux/bootmem_info.h | 2 +-
 mm/bootmem_info.c            | 7 +++----
 mm/sparse.c                  | 2 +-
 4 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 36098226a957..96d34ebb20a9 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -981,7 +981,7 @@ static void __meminit free_pagetable(struct page *page, int order)
 	if (PageReserved(page)) {
 		__ClearPageReserved(page);
 
-		magic = (unsigned long)page->freelist;
+		magic = page->index;
 		if (magic == SECTION_INFO || magic == MIX_SECTION_INFO) {
 			while (nr_pages--)
 				put_page_bootmem(page++);
diff --git a/include/linux/bootmem_info.h b/include/linux/bootmem_info.h
index 2bc8b1f69c93..cc35d010fa94 100644
--- a/include/linux/bootmem_info.h
+++ b/include/linux/bootmem_info.h
@@ -30,7 +30,7 @@ void put_page_bootmem(struct page *page);
  */
 static inline void free_bootmem_page(struct page *page)
 {
-	unsigned long magic = (unsigned long)page->freelist;
+	unsigned long magic = page->index;
 
 	/*
 	 * The reserve_bootmem_region sets the reserved flag on bootmem
diff --git a/mm/bootmem_info.c b/mm/bootmem_info.c
index f03f42f426f6..f18a631e7479 100644
--- a/mm/bootmem_info.c
+++ b/mm/bootmem_info.c
@@ -15,7 +15,7 @@
 
 void get_page_bootmem(unsigned long info, struct page *page, unsigned long type)
 {
-	page->freelist = (void *)type;
+	page->index = type;
 	SetPagePrivate(page);
 	set_page_private(page, info);
 	page_ref_inc(page);
@@ -23,14 +23,13 @@ void get_page_bootmem(unsigned long info, struct page *page, unsigned long type)
 
 void put_page_bootmem(struct page *page)
 {
-	unsigned long type;
+	unsigned long type = page->index;
 
-	type = (unsigned long) page->freelist;
 	BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
 	       type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
 
 	if (page_ref_dec_return(page) == 1) {
-		page->freelist = NULL;
+		page->index = 0;
 		ClearPagePrivate(page);
 		set_page_private(page, 0);
 		INIT_LIST_HEAD(&page->lru);
diff --git a/mm/sparse.c b/mm/sparse.c
index e5c84b0cf0c9..d21c6e5910d0 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -722,7 +722,7 @@ static void free_map_bootmem(struct page *memmap)
 		>> PAGE_SHIFT;
 
 	for (i = 0; i < nr_pages; i++, page++) {
-		magic = (unsigned long) page->freelist;
+		magic = page->index;
 
 		BUG_ON(magic == NODE_INFO);
 
-- 
2.33.1

Re: [PATCH v2 28/33] bootmem: Use page->index instead of page->freelist

[Johannes Weiner]

On Wed, Dec 01, 2021 at 07:15:05PM +0100, Vlastimil Babka wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> page->freelist is for the use of slab.  Using page->index is the same
> set of bits as page->freelist, and by using an integer instead of a
> pointer, we can avoid casts.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: <x86@kernel.org>
> Cc: "H. Peter Anvin" <hpa@zytor.com>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

[PATCH v2 29/33] iommu: Use put_pages_list

[Vlastimil Babka]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

page->freelist is for the use of slab.  We already have the ability
to free a list of pages in the core mm, but it requires the use of a
list_head and for the pages to be chained together through page->lru.
Switch the iommu code over to using put_pages_list().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: Will Deacon <will@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Cc: <iommu@lists.linux-foundation.org>
---
 drivers/iommu/amd/io_pgtable.c | 59 +++++++++-------------
 drivers/iommu/dma-iommu.c      | 11 +----
 drivers/iommu/intel/iommu.c    | 89 ++++++++++++----------------------
 include/linux/iommu.h          |  3 +-
 4 files changed, 57 insertions(+), 105 deletions(-)

diff --git a/drivers/iommu/amd/io_pgtable.c b/drivers/iommu/amd/io_pgtable.c
index 182c93a43efd..08ea6a02cda9 100644
--- a/drivers/iommu/amd/io_pgtable.c
+++ b/drivers/iommu/amd/io_pgtable.c
@@ -74,27 +74,15 @@ static u64 *first_pte_l7(u64 *pte, unsigned long *page_size,
  *
  ****************************************************************************/
 
-static void free_page_list(struct page *freelist)
-{
-	while (freelist != NULL) {
-		unsigned long p = (unsigned long)page_address(freelist);
-
-		freelist = freelist->freelist;
-		free_page(p);
-	}
-}
-
-static struct page *free_pt_page(unsigned long pt, struct page *freelist)
+static void free_pt_page(unsigned long pt, struct list_head *list)
 {
 	struct page *p = virt_to_page((void *)pt);
 
-	p->freelist = freelist;
-
-	return p;
+	list_add(&p->lru, list);
 }
 
 #define DEFINE_FREE_PT_FN(LVL, FN)						\
-static struct page *free_pt_##LVL (unsigned long __pt, struct page *freelist)	\
+static void free_pt_##LVL (unsigned long __pt, struct list_head *list)		\
 {										\
 	unsigned long p;							\
 	u64 *pt;								\
@@ -113,10 +101,10 @@ static struct page *free_pt_##LVL (unsigned long __pt, struct page *freelist)	\
 			continue;						\
 										\
 		p = (unsigned long)IOMMU_PTE_PAGE(pt[i]);			\
-		freelist = FN(p, freelist);					\
+		FN(p, list);							\
 	}									\
 										\
-	return free_pt_page((unsigned long)pt, freelist);			\
+	free_pt_page((unsigned long)pt, list);					\
 }
 
 DEFINE_FREE_PT_FN(l2, free_pt_page)
@@ -125,36 +113,33 @@ DEFINE_FREE_PT_FN(l4, free_pt_l3)
 DEFINE_FREE_PT_FN(l5, free_pt_l4)
 DEFINE_FREE_PT_FN(l6, free_pt_l5)
 
-static struct page *free_sub_pt(unsigned long root, int mode,
-				struct page *freelist)
+static void free_sub_pt(unsigned long root, int mode, struct list_head *list)
 {
 	switch (mode) {
 	case PAGE_MODE_NONE:
 	case PAGE_MODE_7_LEVEL:
 		break;
 	case PAGE_MODE_1_LEVEL:
-		freelist = free_pt_page(root, freelist);
+		free_pt_page(root, list);
 		break;
 	case PAGE_MODE_2_LEVEL:
-		freelist = free_pt_l2(root, freelist);
+		free_pt_l2(root, list);
 		break;
 	case PAGE_MODE_3_LEVEL:
-		freelist = free_pt_l3(root, freelist);
+		free_pt_l3(root, list);
 		break;
 	case PAGE_MODE_4_LEVEL:
-		freelist = free_pt_l4(root, freelist);
+		free_pt_l4(root, list);
 		break;
 	case PAGE_MODE_5_LEVEL:
-		freelist = free_pt_l5(root, freelist);
+		free_pt_l5(root, list);
 		break;
 	case PAGE_MODE_6_LEVEL:
-		freelist = free_pt_l6(root, freelist);
+		free_pt_l6(root, list);
 		break;
 	default:
 		BUG();
 	}
-
-	return freelist;
 }
 
 void amd_iommu_domain_set_pgtable(struct protection_domain *domain,
@@ -362,7 +347,7 @@ static u64 *fetch_pte(struct amd_io_pgtable *pgtable,
 	return pte;
 }
 
-static struct page *free_clear_pte(u64 *pte, u64 pteval, struct page *freelist)
+static void free_clear_pte(u64 *pte, u64 pteval, struct list_head *list)
 {
 	unsigned long pt;
 	int mode;
@@ -373,12 +358,12 @@ static struct page *free_clear_pte(u64 *pte, u64 pteval, struct page *freelist)
 	}
 
 	if (!IOMMU_PTE_PRESENT(pteval))
-		return freelist;
+		return;
 
 	pt   = (unsigned long)IOMMU_PTE_PAGE(pteval);
 	mode = IOMMU_PTE_MODE(pteval);
 
-	return free_sub_pt(pt, mode, freelist);
+	free_sub_pt(pt, mode, list);
 }
 
 /*
@@ -392,7 +377,7 @@ static int iommu_v1_map_page(struct io_pgtable_ops *ops, unsigned long iova,
 			  phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
 {
 	struct protection_domain *dom = io_pgtable_ops_to_domain(ops);
-	struct page *freelist = NULL;
+	LIST_HEAD(freelist);
 	bool updated = false;
 	u64 __pte, *pte;
 	int ret, i, count;
@@ -412,9 +397,9 @@ static int iommu_v1_map_page(struct io_pgtable_ops *ops, unsigned long iova,
 		goto out;
 
 	for (i = 0; i < count; ++i)
-		freelist = free_clear_pte(&pte[i], pte[i], freelist);
+		free_clear_pte(&pte[i], pte[i], &freelist);
 
-	if (freelist != NULL)
+	if (!list_empty(&freelist))
 		updated = true;
 
 	if (count > 1) {
@@ -449,7 +434,7 @@ static int iommu_v1_map_page(struct io_pgtable_ops *ops, unsigned long iova,
 	}
 
 	/* Everything flushed out, free pages now */
-	free_page_list(freelist);
+	put_pages_list(&freelist);
 
 	return ret;
 }
@@ -511,7 +496,7 @@ static void v1_free_pgtable(struct io_pgtable *iop)
 {
 	struct amd_io_pgtable *pgtable = container_of(iop, struct amd_io_pgtable, iop);
 	struct protection_domain *dom;
-	struct page *freelist = NULL;
+	LIST_HEAD(freelist);
 	unsigned long root;
 
 	if (pgtable->mode == PAGE_MODE_NONE)
@@ -530,9 +515,9 @@ static void v1_free_pgtable(struct io_pgtable *iop)
 	       pgtable->mode > PAGE_MODE_6_LEVEL);
 
 	root = (unsigned long)pgtable->root;
-	freelist = free_sub_pt(root, pgtable->mode, freelist);
+	free_sub_pt(root, pgtable->mode, &freelist);
 
-	free_page_list(freelist);
+	put_pages_list(&freelist);
 }
 
 static struct io_pgtable *v1_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index b42e38a0dbe2..e61881c2c258 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -66,14 +66,7 @@ early_param("iommu.forcedac", iommu_dma_forcedac_setup);
 
 static void iommu_dma_entry_dtor(unsigned long data)
 {
-	struct page *freelist = (struct page *)data;
-
-	while (freelist) {
-		unsigned long p = (unsigned long)page_address(freelist);
-
-		freelist = freelist->freelist;
-		free_page(p);
-	}
+	put_pages_list((struct list_head *)data);
 }
 
 static inline size_t cookie_msi_granule(struct iommu_dma_cookie *cookie)
@@ -479,7 +472,7 @@ static void iommu_dma_free_iova(struct iommu_dma_cookie *cookie,
 	else if (gather && gather->queued)
 		queue_iova(iovad, iova_pfn(iovad, iova),
 				size >> iova_shift(iovad),
-				(unsigned long)gather->freelist);
+				(unsigned long)&gather->freelist);
 	else
 		free_iova_fast(iovad, iova_pfn(iovad, iova),
 				size >> iova_shift(iovad));
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index b6a8f3282411..cd2ec6779cac 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -1303,35 +1303,30 @@ static void dma_pte_free_pagetable(struct dmar_domain *domain,
    know the hardware page-walk will no longer touch them.
    The 'pte' argument is the *parent* PTE, pointing to the page that is to
    be freed. */
-static struct page *dma_pte_list_pagetables(struct dmar_domain *domain,
-					    int level, struct dma_pte *pte,
-					    struct page *freelist)
+static void dma_pte_list_pagetables(struct dmar_domain *domain,
+				    int level, struct dma_pte *pte,
+				    struct list_head *list)
 {
 	struct page *pg;
 
 	pg = pfn_to_page(dma_pte_addr(pte) >> PAGE_SHIFT);
-	pg->freelist = freelist;
-	freelist = pg;
+	list_add(&pg->lru, list);
 
 	if (level == 1)
-		return freelist;
+		return;
 
 	pte = page_address(pg);
 	do {
 		if (dma_pte_present(pte) && !dma_pte_superpage(pte))
-			freelist = dma_pte_list_pagetables(domain, level - 1,
-							   pte, freelist);
+			dma_pte_list_pagetables(domain, level - 1, pte, list);
 		pte++;
 	} while (!first_pte_in_page(pte));
-
-	return freelist;
 }
 
-static struct page *dma_pte_clear_level(struct dmar_domain *domain, int level,
-					struct dma_pte *pte, unsigned long pfn,
-					unsigned long start_pfn,
-					unsigned long last_pfn,
-					struct page *freelist)
+static void dma_pte_clear_level(struct dmar_domain *domain, int level,
+				struct dma_pte *pte, unsigned long pfn,
+				unsigned long start_pfn, unsigned long last_pfn,
+				struct list_head *list)
 {
 	struct dma_pte *first_pte = NULL, *last_pte = NULL;
 
@@ -1350,7 +1345,7 @@ static struct page *dma_pte_clear_level(struct dmar_domain *domain, int level,
 			/* These suborbinate page tables are going away entirely. Don't
 			   bother to clear them; we're just going to *free* them. */
 			if (level > 1 && !dma_pte_superpage(pte))
-				freelist = dma_pte_list_pagetables(domain, level - 1, pte, freelist);
+				dma_pte_list_pagetables(domain, level - 1, pte, list);
 
 			dma_clear_pte(pte);
 			if (!first_pte)
@@ -1358,10 +1353,10 @@ static struct page *dma_pte_clear_level(struct dmar_domain *domain, int level,
 			last_pte = pte;
 		} else if (level > 1) {
 			/* Recurse down into a level that isn't *entirely* obsolete */
-			freelist = dma_pte_clear_level(domain, level - 1,
-						       phys_to_virt(dma_pte_addr(pte)),
-						       level_pfn, start_pfn, last_pfn,
-						       freelist);
+			dma_pte_clear_level(domain, level - 1,
+					    phys_to_virt(dma_pte_addr(pte)),
+					    level_pfn, start_pfn, last_pfn,
+					    list);
 		}
 next:
 		pfn = level_pfn + level_size(level);
@@ -1370,47 +1365,28 @@ static struct page *dma_pte_clear_level(struct dmar_domain *domain, int level,
 	if (first_pte)
 		domain_flush_cache(domain, first_pte,
 				   (void *)++last_pte - (void *)first_pte);
-
-	return freelist;
 }
 
 /* We can't just free the pages because the IOMMU may still be walking
    the page tables, and may have cached the intermediate levels. The
    pages can only be freed after the IOTLB flush has been done. */
-static struct page *domain_unmap(struct dmar_domain *domain,
-				 unsigned long start_pfn,
-				 unsigned long last_pfn,
-				 struct page *freelist)
+static void domain_unmap(struct dmar_domain *domain, unsigned long start_pfn,
+			 unsigned long last_pfn, struct list_head *list)
 {
 	BUG_ON(!domain_pfn_supported(domain, start_pfn));
 	BUG_ON(!domain_pfn_supported(domain, last_pfn));
 	BUG_ON(start_pfn > last_pfn);
 
 	/* we don't need lock here; nobody else touches the iova range */
-	freelist = dma_pte_clear_level(domain, agaw_to_level(domain->agaw),
-				       domain->pgd, 0, start_pfn, last_pfn,
-				       freelist);
+	dma_pte_clear_level(domain, agaw_to_level(domain->agaw),
+			    domain->pgd, 0, start_pfn, last_pfn, list);
 
 	/* free pgd */
 	if (start_pfn == 0 && last_pfn == DOMAIN_MAX_PFN(domain->gaw)) {
 		struct page *pgd_page = virt_to_page(domain->pgd);
-		pgd_page->freelist = freelist;
-		freelist = pgd_page;
-
+		list_add(&pgd_page->lru, list);
 		domain->pgd = NULL;
 	}
-
-	return freelist;
-}
-
-static void dma_free_pagelist(struct page *freelist)
-{
-	struct page *pg;
-
-	while ((pg = freelist)) {
-		freelist = pg->freelist;
-		free_pgtable_page(page_address(pg));
-	}
 }
 
 /* iommu handling */
@@ -2095,11 +2071,10 @@ static void domain_exit(struct dmar_domain *domain)
 	domain_remove_dev_info(domain);
 
 	if (domain->pgd) {
-		struct page *freelist;
+		LIST_HEAD(pages);
 
-		freelist = domain_unmap(domain, 0,
-					DOMAIN_MAX_PFN(domain->gaw), NULL);
-		dma_free_pagelist(freelist);
+		domain_unmap(domain, 0, DOMAIN_MAX_PFN(domain->gaw), &pages);
+		put_pages_list(&pages);
 	}
 
 	free_domain_mem(domain);
@@ -4192,19 +4167,17 @@ static int intel_iommu_memory_notifier(struct notifier_block *nb,
 		{
 			struct dmar_drhd_unit *drhd;
 			struct intel_iommu *iommu;
-			struct page *freelist;
+			LIST_HEAD(pages);
 
-			freelist = domain_unmap(si_domain,
-						start_vpfn, last_vpfn,
-						NULL);
+			domain_unmap(si_domain, start_vpfn, last_vpfn, &pages);
 
 			rcu_read_lock();
 			for_each_active_iommu(iommu, drhd)
 				iommu_flush_iotlb_psi(iommu, si_domain,
 					start_vpfn, mhp->nr_pages,
-					!freelist, 0);
+					list_empty(&pages), 0);
 			rcu_read_unlock();
-			dma_free_pagelist(freelist);
+			put_pages_list(&pages);
 		}
 		break;
 	}
@@ -5211,8 +5184,7 @@ static size_t intel_iommu_unmap(struct iommu_domain *domain,
 	start_pfn = iova >> VTD_PAGE_SHIFT;
 	last_pfn = (iova + size - 1) >> VTD_PAGE_SHIFT;
 
-	gather->freelist = domain_unmap(dmar_domain, start_pfn,
-					last_pfn, gather->freelist);
+	domain_unmap(dmar_domain, start_pfn, last_pfn, &gather->freelist);
 
 	if (dmar_domain->max_addr == iova + size)
 		dmar_domain->max_addr = iova;
@@ -5248,9 +5220,10 @@ static void intel_iommu_tlb_sync(struct iommu_domain *domain,
 
 	for_each_domain_iommu(iommu_id, dmar_domain)
 		iommu_flush_iotlb_psi(g_iommus[iommu_id], dmar_domain,
-				      start_pfn, nrpages, !gather->freelist, 0);
+				      start_pfn, nrpages,
+				      list_empty(&gather->freelist), 0);
 
-	dma_free_pagelist(gather->freelist);
+	put_pages_list(&gather->freelist);
 }
 
 static phys_addr_t intel_iommu_iova_to_phys(struct iommu_domain *domain,
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index d2f3435e7d17..de0c57a567c8 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -186,7 +186,7 @@ struct iommu_iotlb_gather {
 	unsigned long		start;
 	unsigned long		end;
 	size_t			pgsize;
-	struct page		*freelist;
+	struct list_head	freelist;
 	bool			queued;
 };
 
@@ -399,6 +399,7 @@ static inline void iommu_iotlb_gather_init(struct iommu_iotlb_gather *gather)
 {
 	*gather = (struct iommu_iotlb_gather) {
 		.start	= ULONG_MAX,
+		.freelist = LIST_HEAD_INIT(gather->freelist),
 	};
 }
 
-- 
2.33.1

Re: [PATCH v2 29/33] iommu: Use put_pages_list

[Matthew Wilcox]

On Wed, Dec 01, 2021 at 07:15:06PM +0100, Vlastimil Babka wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> page->freelist is for the use of slab.  We already have the ability
> to free a list of pages in the core mm, but it requires the use of a
> list_head and for the pages to be chained together through page->lru.
> Switch the iommu code over to using put_pages_list().

FYI, this is going to have conflicts with
https://lore.kernel.org/lkml/cover.1637671820.git.robin.murphy@arm.com/

I'm not sure what the appropriate resolution is going to be here;
maybe hold back part of this patch series to the following merge
window to give the iommu people time to merge their own patches?

Re: [PATCH v2 29/33] iommu: Use put_pages_list

[Robin Murphy]

On 2021-12-01 19:07, Matthew Wilcox wrote:
> On Wed, Dec 01, 2021 at 07:15:06PM +0100, Vlastimil Babka wrote:
>> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
>>
>> page->freelist is for the use of slab.  We already have the ability
>> to free a list of pages in the core mm, but it requires the use of a
>> list_head and for the pages to be chained together through page->lru.
>> Switch the iommu code over to using put_pages_list().
> 
> FYI, this is going to have conflicts with
> https://lore.kernel.org/lkml/cover.1637671820.git.robin.murphy@arm.com/
> 
> I'm not sure what the appropriate resolution is going to be here;
> maybe hold back part of this patch series to the following merge
> window to give the iommu people time to merge their own patches?

More than that, this version is subtly but catastrophically broken - we 
can't simply pass &gather->freelist through the current IOVA entry_dtor 
machinery, since gather is a stack variable from a few call frames up so 
the actual list head will be long gone by the time 
iommu_dma_entry_dtor() tries to dereference it. It took until I was 
elbow-deep in refactoring the RFC to notice that one :)

Thanks,
Robin.

[PATCH v2 30/33] mm: Remove slab from struct page

[Vlastimil Babka]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

All members of struct slab can now be removed from struct page.
This shrinks the definition of struct page by 30 LOC, making
it easier to understand.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 include/linux/mm_types.h   | 28 ----------------------------
 include/linux/page-flags.h | 37 -------------------------------------
 mm/slab.h                  |  4 ----
 3 files changed, 69 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 1ae3537c7920..646f3ed4f6df 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -118,31 +118,6 @@ struct page {
 				atomic_long_t pp_frag_count;
 			};
 		};
-		struct {	/* slab, slob and slub */
-			union {
-				struct list_head slab_list;
-				struct {	/* Partial pages */
-					struct page *next;
-#ifdef CONFIG_64BIT
-					int pages;	/* Nr of pages left */
-#else
-					short int pages;
-#endif
-				};
-			};
-			struct kmem_cache *slab_cache; /* not slob */
-			/* Double-word boundary */
-			void *freelist;		/* first free object */
-			union {
-				void *s_mem;	/* slab: first object */
-				unsigned long counters;		/* SLUB */
-				struct {			/* SLUB */
-					unsigned inuse:16;
-					unsigned objects:15;
-					unsigned frozen:1;
-				};
-			};
-		};
 		struct {	/* Tail pages of compound page */
 			unsigned long compound_head;	/* Bit zero is set */
 
@@ -206,9 +181,6 @@ struct page {
 		 * which are currently stored here.
 		 */
 		unsigned int page_type;
-
-		unsigned int active;		/* SLAB */
-		int units;			/* SLOB */
 	};
 
 	/* Usage count. *DO NOT USE DIRECTLY*. See page_ref.h */
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index b5f14d581113..1b08e33265fa 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -909,43 +909,6 @@ extern bool is_free_buddy_page(struct page *page);
 
 __PAGEFLAG(Isolated, isolated, PF_ANY);
 
-/*
- * If network-based swap is enabled, sl*b must keep track of whether pages
- * were allocated from pfmemalloc reserves.
- */
-static inline int PageSlabPfmemalloc(struct page *page)
-{
-	VM_BUG_ON_PAGE(!PageSlab(page), page);
-	return PageActive(page);
-}
-
-/*
- * A version of PageSlabPfmemalloc() for opportunistic checks where the page
- * might have been freed under us and not be a PageSlab anymore.
- */
-static inline int __PageSlabPfmemalloc(struct page *page)
-{
-	return PageActive(page);
-}
-
-static inline void SetPageSlabPfmemalloc(struct page *page)
-{
-	VM_BUG_ON_PAGE(!PageSlab(page), page);
-	SetPageActive(page);
-}
-
-static inline void __ClearPageSlabPfmemalloc(struct page *page)
-{
-	VM_BUG_ON_PAGE(!PageSlab(page), page);
-	__ClearPageActive(page);
-}
-
-static inline void ClearPageSlabPfmemalloc(struct page *page)
-{
-	VM_BUG_ON_PAGE(!PageSlab(page), page);
-	ClearPageActive(page);
-}
-
 #ifdef CONFIG_MMU
 #define __PG_MLOCKED		(1UL << PG_mlocked)
 #else
diff --git a/mm/slab.h b/mm/slab.h
index 0760f20686a7..2d50c099a222 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -47,11 +47,7 @@ struct slab {
 	static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl))
 SLAB_MATCH(flags, __page_flags);
 SLAB_MATCH(compound_head, slab_list);	/* Ensure bit 0 is clear */
-SLAB_MATCH(slab_list, slab_list);
 SLAB_MATCH(rcu_head, rcu_head);
-SLAB_MATCH(slab_cache, slab_cache);
-SLAB_MATCH(s_mem, s_mem);
-SLAB_MATCH(active, active);
 SLAB_MATCH(_refcount, __page_refcount);
 #ifdef CONFIG_MEMCG
 SLAB_MATCH(memcg_data, memcg_data);
-- 
2.33.1

Re: [PATCH v2 30/33] mm: Remove slab from struct page

[Johannes Weiner]

On Wed, Dec 01, 2021 at 07:15:07PM +0100, Vlastimil Babka wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> All members of struct slab can now be removed from struct page.
> This shrinks the definition of struct page by 30 LOC, making
> it easier to understand.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

[PATCH v2 31/33] mm/sl*b: Differentiate struct slab fields by sl*b implementations

[Vlastimil Babka]

With a struct slab definition separate from struct page, we can go further and
define only fields that the chosen sl*b implementation uses. This means
everything between __page_flags and __page_refcount placeholders now depends on
the chosen CONFIG_SL*B. Some fields exist in all implementations (slab_list)
but can be part of a union in some, so it's simpler to repeat them than
complicate the definition with ifdefs even more.

The patch doesn't change physical offsets of the fields, although it could be
done later - for example it's now clear that tighter packing in SLOB could be
possible.

This should also prevent accidental use of fields that don't exist in given
implementation. Before this patch virt_to_cache() and and cache_from_obj() was
visible for SLOB (albeit not used), although it relies on the slab_cache field
that isn't set by SLOB. With this patch it's now a compile error, so these
functions are now hidden behind #ifndef CONFIG_SLOB.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Marco Elver <elver@google.com> # kfence
Cc: Alexander Potapenko <glider@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: <kasan-dev@googlegroups.com>
---
 mm/kfence/core.c |  9 +++++----
 mm/slab.h        | 46 ++++++++++++++++++++++++++++++++++++----------
 2 files changed, 41 insertions(+), 14 deletions(-)

diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 4eb60cf5ff8b..46103a7628a6 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -427,10 +427,11 @@ static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t g
 	/* Set required slab fields. */
 	slab = virt_to_slab((void *)meta->addr);
 	slab->slab_cache = cache;
-	if (IS_ENABLED(CONFIG_SLUB))
-		slab->objects = 1;
-	if (IS_ENABLED(CONFIG_SLAB))
-		slab->s_mem = addr;
+#if defined(CONFIG_SLUB)
+	slab->objects = 1;
+#elif defined (CONFIG_SLAB)
+	slab->s_mem = addr;
+#endif
 
 	/* Memory initialization. */
 	for_each_canary(meta, set_canary_byte);
diff --git a/mm/slab.h b/mm/slab.h
index 2d50c099a222..8c5a8c005896 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -8,9 +8,24 @@
 /* Reuses the bits in struct page */
 struct slab {
 	unsigned long __page_flags;
+
+#if defined(CONFIG_SLAB)
+
+	union {
+		struct list_head slab_list;
+		struct rcu_head rcu_head;
+	};
+	struct kmem_cache *slab_cache;
+	void *freelist;	/* array of free object indexes */
+	void * s_mem;	/* first object */
+	unsigned int active;
+
+#elif defined(CONFIG_SLUB)
+
 	union {
 		struct list_head slab_list;
-		struct {	/* Partial pages */
+		struct rcu_head rcu_head;
+		struct {
 			struct slab *next;
 #ifdef CONFIG_64BIT
 			int slabs;	/* Nr of slabs left */
@@ -18,25 +33,32 @@ struct slab {
 			short int slabs;
 #endif
 		};
-		struct rcu_head rcu_head;
 	};
-	struct kmem_cache *slab_cache; /* not slob */
+	struct kmem_cache *slab_cache;
 	/* Double-word boundary */
 	void *freelist;		/* first free object */
 	union {
-		void *s_mem;	/* slab: first object */
-		unsigned long counters;		/* SLUB */
-		struct {			/* SLUB */
+		unsigned long counters;
+		struct {
 			unsigned inuse:16;
 			unsigned objects:15;
 			unsigned frozen:1;
 		};
 	};
+	unsigned int __unused;
+
+#elif defined(CONFIG_SLOB)
+
+	struct list_head slab_list;
+	void * __unused_1;
+	void *freelist;		/* first free block */
+	void * __unused_2;
+	int units;
+
+#else
+#error "Unexpected slab allocator configured"
+#endif
 
-	union {
-		unsigned int active;		/* SLAB */
-		int units;			/* SLOB */
-	};
 	atomic_t __page_refcount;
 #ifdef CONFIG_MEMCG
 	unsigned long memcg_data;
@@ -47,7 +69,9 @@ struct slab {
 	static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl))
 SLAB_MATCH(flags, __page_flags);
 SLAB_MATCH(compound_head, slab_list);	/* Ensure bit 0 is clear */
+#ifndef CONFIG_SLOB
 SLAB_MATCH(rcu_head, rcu_head);
+#endif
 SLAB_MATCH(_refcount, __page_refcount);
 #ifdef CONFIG_MEMCG
 SLAB_MATCH(memcg_data, memcg_data);
@@ -623,6 +647,7 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s,
 }
 #endif /* CONFIG_MEMCG_KMEM */
 
+#ifndef CONFIG_SLOB
 static inline struct kmem_cache *virt_to_cache(const void *obj)
 {
 	struct slab *slab;
@@ -669,6 +694,7 @@ static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
 		print_tracking(cachep, x);
 	return cachep;
 }
+#endif /* CONFIG_SLOB */
 
 static inline size_t slab_ksize(const struct kmem_cache *s)
 {
-- 
2.33.1

Re: [PATCH v2 31/33] mm/sl*b: Differentiate struct slab fields by sl*b implementations

[Hyeonggon Yoo]

On Wed, Dec 01, 2021 at 07:15:08PM +0100, Vlastimil Babka wrote:
> With a struct slab definition separate from struct page, we can go further and
> define only fields that the chosen sl*b implementation uses. This means
> everything between __page_flags and __page_refcount placeholders now depends on
> the chosen CONFIG_SL*B.

When I read this patch series first, I thought struct slab is allocated
separately from struct page.

But after reading it again, It uses same allocated space of struct page.

So, the code should care about fields that page allocator cares when
freeing page. (->mapping, ->refcount, ->flags, ...)

And, we can change offset of fields between page->flags and page->refcount,
If we care about the value of page->mapping before freeing it.

Did I get it right?

> Some fields exist in all implementations (slab_list)
> but can be part of a union in some, so it's simpler to repeat them than
> complicate the definition with ifdefs even more.

Before this patch I always ran preprocessor in my brain.
now it's MUCH easier to understand than before!

> 
> The patch doesn't change physical offsets of the fields, although it could be
> done later - for example it's now clear that tighter packing in SLOB could be
> possible.
>

Is there a benefit if we pack SLOB's struct slab tighter?

...

>  #ifdef CONFIG_MEMCG
>  	unsigned long memcg_data;
> @@ -47,7 +69,9 @@ struct slab {
>  	static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl))
>  SLAB_MATCH(flags, __page_flags);
>  SLAB_MATCH(compound_head, slab_list);	/* Ensure bit 0 is clear */
> +#ifndef CONFIG_SLOB
>  SLAB_MATCH(rcu_head, rcu_head);

Because SLUB and SLAB sets slab->slab_cache = NULL (to set page->mapping = NULL),
What about adding this?:

SLAB_MATCH(mapping, slab_cache);

there was SLAB_MATCH(slab_cache, slab_cache) but removed.

> +#endif
>  SLAB_MATCH(_refcount, __page_refcount);
>  #ifdef CONFIG_MEMCG
>  SLAB_MATCH(memcg_data, memcg_data);

I couldn't find any functional problem on this patch.
but it seems there's some style issues.

Below is what checkpatch.pl complains.
it's better to fix them!

WARNING: Possible unwrapped commit description (prefer a maximum 75 chars per line)
#7: 
With a struct slab definition separate from struct page, we can go further and

WARNING: Possible repeated word: 'and'
#19: 
implementation. Before this patch virt_to_cache() and and cache_from_obj() was

WARNING: space prohibited between function name and open parenthesis '('
#49: FILE: mm/kfence/core.c:432:
+#elif defined (CONFIG_SLAB)

ERROR: "foo * bar" should be "foo *bar"
#73: FILE: mm/slab.h:20:
+void * s_mem;/* first object */

ERROR: "foo * bar" should be "foo *bar"
#111: FILE: mm/slab.h:53:
+void * __unused_1;

ERROR: "foo * bar" should be "foo *bar"
#113: FILE: mm/slab.h:55:
+void * __unused_2;

---
Thanks,
Hyeonggon.

Re: [PATCH v2 31/33] mm/sl*b: Differentiate struct slab fields by sl*b implementations

[Vlastimil Babka]

On 12/10/21 17:37, Hyeonggon Yoo wrote:
> On Wed, Dec 01, 2021 at 07:15:08PM +0100, Vlastimil Babka wrote:
>> With a struct slab definition separate from struct page, we can go further and
>> define only fields that the chosen sl*b implementation uses. This means
>> everything between __page_flags and __page_refcount placeholders now depends on
>> the chosen CONFIG_SL*B.
> 
> When I read this patch series first, I thought struct slab is allocated
> separately from struct page.
> 
> But after reading it again, It uses same allocated space of struct page.

Yes. Allocating it elsewhere is something that can be discussed later. It's
not a simple clear win - more memory used, more overhead, complicated code...

> So, the code should care about fields that page allocator cares when
> freeing page. (->mapping, ->refcount, ->flags, ...)
> 
> And, we can change offset of fields between page->flags and page->refcount,
> If we care about the value of page->mapping before freeing it.
> 
> Did I get it right?

Yeah. Also whatever aliases with compound_head must not have bit zero set as
that means a tail page.

>> Some fields exist in all implementations (slab_list)
>> but can be part of a union in some, so it's simpler to repeat them than
>> complicate the definition with ifdefs even more.
> 
> Before this patch I always ran preprocessor in my brain.
> now it's MUCH easier to understand than before!
> 
>> 
>> The patch doesn't change physical offsets of the fields, although it could be
>> done later - for example it's now clear that tighter packing in SLOB could be
>> possible.
>>
> 
> Is there a benefit if we pack SLOB's struct slab tighter?

I don't see any immediate benefit, except avoiding the page->mapping alias
as you suggested.

> ...
> 
>>  #ifdef CONFIG_MEMCG
>>  	unsigned long memcg_data;
>> @@ -47,7 +69,9 @@ struct slab {
>>  	static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl))
>>  SLAB_MATCH(flags, __page_flags);
>>  SLAB_MATCH(compound_head, slab_list);	/* Ensure bit 0 is clear */
>> +#ifndef CONFIG_SLOB
>>  SLAB_MATCH(rcu_head, rcu_head);
> 
> Because SLUB and SLAB sets slab->slab_cache = NULL (to set page->mapping = NULL),

Hm, now that you mention it, maybe it would be better to do a
"folio->mapping = NULL" instead as we now have a more clearer view where we
operate on struct slab, and where we transition between that and a plain
folio. This is IMHO part of preparing the folio for freeing, not a struct
slab cleanup as struct slab doesn't need this cleanup.

> What about adding this?:
> 
> SLAB_MATCH(mapping, slab_cache);
> 
> there was SLAB_MATCH(slab_cache, slab_cache) but removed.

With the change suggested above, it wouldn't be needed as a safety check
anymore.

>> +#endif
>>  SLAB_MATCH(_refcount, __page_refcount);
>>  #ifdef CONFIG_MEMCG
>>  SLAB_MATCH(memcg_data, memcg_data);
> 
> I couldn't find any functional problem on this patch.
> but it seems there's some style issues.
> 
> Below is what checkpatch.pl complains.
> it's better to fix them!

Not all checkpatch suggestions are correct and have to be followed, but I'll
check what I missed. Thanks.

> WARNING: Possible unwrapped commit description (prefer a maximum 75 chars per line)
> #7: 
> With a struct slab definition separate from struct page, we can go further and
> 
> WARNING: Possible repeated word: 'and'
> #19: 
> implementation. Before this patch virt_to_cache() and and cache_from_obj() was
> 
> WARNING: space prohibited between function name and open parenthesis '('
> #49: FILE: mm/kfence/core.c:432:
> +#elif defined (CONFIG_SLAB)
> 
> ERROR: "foo * bar" should be "foo *bar"
> #73: FILE: mm/slab.h:20:
> +void * s_mem;/* first object */
> 
> ERROR: "foo * bar" should be "foo *bar"
> #111: FILE: mm/slab.h:53:
> +void * __unused_1;
> 
> ERROR: "foo * bar" should be "foo *bar"
> #113: FILE: mm/slab.h:55:
> +void * __unused_2;
> 
> ---
> Thanks,
> Hyeonggon.

Re: [PATCH v2 31/33] mm/sl*b: Differentiate struct slab fields by sl*b implementations

[Hyeonggon Yoo]

On Fri, Dec 10, 2021 at 07:26:11PM +0100, Vlastimil Babka wrote:
> On 12/10/21 17:37, Hyeonggon Yoo wrote:
> > On Wed, Dec 01, 2021 at 07:15:08PM +0100, Vlastimil Babka wrote:
> >> With a struct slab definition separate from struct page, we can go further and
> >> define only fields that the chosen sl*b implementation uses. This means
> >> everything between __page_flags and __page_refcount placeholders now depends on
> >> the chosen CONFIG_SL*B.
> > 
> > When I read this patch series first, I thought struct slab is allocated
> > separately from struct page.
> > 
> > But after reading it again, It uses same allocated space of struct page.
> 
> Yes. Allocating it elsewhere is something that can be discussed later. It's
> not a simple clear win - more memory used, more overhead, complicated code...
>

Right. That is a something that can be discussed,
But I don't think there will be much win.

> > So, the code should care about fields that page allocator cares when
> > freeing page. (->mapping, ->refcount, ->flags, ...)
> > 
> > And, we can change offset of fields between page->flags and page->refcount,
> > If we care about the value of page->mapping before freeing it.
> > 
> > Did I get it right?
> 
> Yeah. Also whatever aliases with compound_head must not have bit zero set as
> that means a tail page.
> 

Oh I was missing that. Thank you.

Hmm then in struct slab, page->compound_head and slab->list_head (or
slab->rcu_head) has same offset. And list_head / rcu_head both store pointers.

then it has a alignment requirement. (address saved in list_head/rcu_head
should be multiple of 2)

Anyway, it was required long time before this patch,
so it is not a problem for this patch.

> >> Some fields exist in all implementations (slab_list)
> >> but can be part of a union in some, so it's simpler to repeat them than
> >> complicate the definition with ifdefs even more.
> > 
> > Before this patch I always ran preprocessor in my brain.
> > now it's MUCH easier to understand than before!
> > 
> >> 
> >> The patch doesn't change physical offsets of the fields, although it could be
> >> done later - for example it's now clear that tighter packing in SLOB could be
> >> possible.
> >>
> > 
> > Is there a benefit if we pack SLOB's struct slab tighter?
> 
> I don't see any immediate benefit, except avoiding the page->mapping alias
> as you suggested.
> 
> > ...
> > 
> >>  #ifdef CONFIG_MEMCG
> >>  	unsigned long memcg_data;
> >> @@ -47,7 +69,9 @@ struct slab {
> >>  	static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl))
> >>  SLAB_MATCH(flags, __page_flags);
> >>  SLAB_MATCH(compound_head, slab_list);	/* Ensure bit 0 is clear */
> >> +#ifndef CONFIG_SLOB
> >>  SLAB_MATCH(rcu_head, rcu_head);
> > 
> > Because SLUB and SLAB sets slab->slab_cache = NULL (to set page->mapping = NULL),
> 
> Hm, now that you mention it, maybe it would be better to do a
> "folio->mapping = NULL" instead as we now have a more clearer view where we
> operate on struct slab, and where we transition between that and a plain
> folio. 

Oh, folio->mapping = NULL seems more intuitive.

And we can reorder fields of struct slab more flexibly with
folio->mapping = NULL because we have no reason to make page->mapping
and slab->slab_cache to have same offset.

So it should be done in separate patch for SLUB/SLAB.
Do you mind If I send a patch for this after some testing?

> This is IMHO part of preparing the folio for freeing, not a struct
> slab cleanup as struct slab doesn't need this cleanup.

I agree that. it's needed for folio, not for struct slab.

> > What about adding this?:
> > 
> > SLAB_MATCH(mapping, slab_cache);
> > 
> > there was SLAB_MATCH(slab_cache, slab_cache) but removed.
> 
> With the change suggested above, it wouldn't be needed as a safety check
> anymore.
> 

Okay.

> >> +#endif
> >>  SLAB_MATCH(_refcount, __page_refcount);
> >>  #ifdef CONFIG_MEMCG
> >>  SLAB_MATCH(memcg_data, memcg_data);
> > 
> > I couldn't find any functional problem on this patch.
> > but it seems there's some style issues.
> > 
> > Below is what checkpatch.pl complains.
> > it's better to fix them!
> 
> Not all checkpatch suggestions are correct and have to be followed, but I'll
> check what I missed. Thanks.
>

You're welcome.
They are just a typo in changelog and white space warnings.

So now, exept few style issues, I can't find any problem in this patch.
And this patch gives us much better view of struct slab.

Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

Thanks,
Hyeonggon.

> > WARNING: Possible unwrapped commit description (prefer a maximum 75 chars per line)
> > #7: 
> > With a struct slab definition separate from struct page, we can go further and
> > 
> > WARNING: Possible repeated word: 'and'
> > #19: 
> > implementation. Before this patch virt_to_cache() and and cache_from_obj() was
> > 
> > WARNING: space prohibited between function name and open parenthesis '('
> > #49: FILE: mm/kfence/core.c:432:
> > +#elif defined (CONFIG_SLAB)
> > 
> > ERROR: "foo * bar" should be "foo *bar"
> > #73: FILE: mm/slab.h:20:
> > +void * s_mem;/* first object */
> > 
> > ERROR: "foo * bar" should be "foo *bar"
> > #111: FILE: mm/slab.h:53:
> > +void * __unused_1;
> > 
> > ERROR: "foo * bar" should be "foo *bar"
> > #113: FILE: mm/slab.h:55:
> > +void * __unused_2;
> > 
> > ---
> > Thanks,
> > Hyeonggon.
> 

Re: [PATCH v2 31/33] mm/sl*b: Differentiate struct slab fields by sl*b implementations

[Matthew Wilcox]

On Sat, Dec 11, 2021 at 11:55:27AM +0000, Hyeonggon Yoo wrote:
> On Fri, Dec 10, 2021 at 07:26:11PM +0100, Vlastimil Babka wrote:
> > On 12/10/21 17:37, Hyeonggon Yoo wrote:
> > > On Wed, Dec 01, 2021 at 07:15:08PM +0100, Vlastimil Babka wrote:
> > >> With a struct slab definition separate from struct page, we can go further and
> > >> define only fields that the chosen sl*b implementation uses. This means
> > >> everything between __page_flags and __page_refcount placeholders now depends on
> > >> the chosen CONFIG_SL*B.
> > > 
> > > When I read this patch series first, I thought struct slab is allocated
> > > separately from struct page.
> > > 
> > > But after reading it again, It uses same allocated space of struct page.
> > 
> > Yes. Allocating it elsewhere is something that can be discussed later. It's
> > not a simple clear win - more memory used, more overhead, complicated code...
> >
> 
> Right. That is a something that can be discussed,
> But I don't think there will be much win.

Oh no, there's a substantial win.  If we can reduce struct page to a
single pointer, that shrinks it from 64 bytes/4k to 8 bytes/4k.  Set
against that, you have to allocate the struct folio / struct slab / ...
but then it's one _per allocation_ rather than one per page.  So for
an order-2 allocation, it takes 32 bytes + 64 bytes (= 96 bytes)
rather than 4*64 = 256 bytes.  It's an even bigger win for larger
allocations, and it lets us grow the memory descriptors independently
of each other.

But it's also a substantial amount of work, so don't expect us to get
there any time soon.  Everything currently using struct page needs to
be converted to use another type, and that's just the pre-requisite
step.

Some more thoughts on this here:
https://lore.kernel.org/linux-mm/YXcLqcFhDq3uUwIj@casper.infradead.org/

> > Yeah. Also whatever aliases with compound_head must not have bit zero set as
> > that means a tail page.
> > 
> 
> Oh I was missing that. Thank you.
> 
> Hmm then in struct slab, page->compound_head and slab->list_head (or
> slab->rcu_head) has same offset. And list_head / rcu_head both store pointers.
> 
> then it has a alignment requirement. (address saved in list_head/rcu_head
> should be multiple of 2)
> 
> Anyway, it was required long time before this patch,
> so it is not a problem for this patch.

Yes, that's why there's an assert that the list_heads all line up.  This
requirement will go away if we do get separately allocated memory
descriptors (because that bottom bit is no longer PageTail).

Re: [PATCH v2 31/33] mm/sl*b: Differentiate struct slab fields by sl*b implementations

[Hyeonggon Yoo]

On Sat, Dec 11, 2021 at 04:52:47PM +0000, Matthew Wilcox wrote:
> On Sat, Dec 11, 2021 at 11:55:27AM +0000, Hyeonggon Yoo wrote:
> > On Fri, Dec 10, 2021 at 07:26:11PM +0100, Vlastimil Babka wrote:
> > > On 12/10/21 17:37, Hyeonggon Yoo wrote:
> > > > On Wed, Dec 01, 2021 at 07:15:08PM +0100, Vlastimil Babka wrote:
> > > >> With a struct slab definition separate from struct page, we can go further and
> > > >> define only fields that the chosen sl*b implementation uses. This means
> > > >> everything between __page_flags and __page_refcount placeholders now depends on
> > > >> the chosen CONFIG_SL*B.
> > > > 
> > > > When I read this patch series first, I thought struct slab is allocated
> > > > separately from struct page.
> > > > 
> > > > But after reading it again, It uses same allocated space of struct page.
> > > 
> > > Yes. Allocating it elsewhere is something that can be discussed later. It's
> > > not a simple clear win - more memory used, more overhead, complicated code...
> > >
> > 
> > Right. That is a something that can be discussed,
> > But I don't think there will be much win.
> 
> Oh no, there's a substantial win.  If we can reduce struct page to a
> single pointer, that shrinks it from 64 bytes/4k to 8 bytes/4k.  Set
> against that, you have to allocate the struct folio / struct slab / ...
> but then it's one _per allocation_ rather than one per page.  So for
> an order-2 allocation, it takes 32 bytes + 64 bytes (= 96 bytes)
> rather than 4*64 = 256 bytes.  It's an even bigger win for larger
> allocations, and it lets us grow the memory descriptors independently
> of each other.

Oh I thought there won't be much win because I thought it was
just allocating additional memory for struct slab and still allocating
memory for struct page as we do now.

It will be more efficient if we can allocate descriptor of slab/page/...etc
per *allocation*, which may have order > 1. And currently we're
duplicating memory descriptor (struct page) even on high order
allocation.

Even if we do not allocate high order page at all, it's
still efficient if we can reduce struct page into double word.
And we can allocate something like struct slab only when we need it. 

One challenge here is that we should allocate the descriptors
dynamically... I'm going to read the link you sent.

> Everything currently using struct page needs to
> be converted to use another type, and that's just the pre-requisite
> step.
> 

Oh, you're planning to separate *everything* from
struct page, not only struct slab!

So your intention of this patch series is preparing for
physical separation. It's fascinating...

> But it's also a substantial amount of work, so don't expect us to get
> there any time soon.

Yeah, that will require much work. But I'll wait for your good work.
It's so interesting.

> Some more thoughts on this here:
> https://lore.kernel.org/linux-mm/YXcLqcFhDq3uUwIj@casper.infradead.org/
> 

Thank you for the link.

> > > Yeah. Also whatever aliases with compound_head must not have bit zero set as
> > > that means a tail page.
> > > 
> > 
> > Oh I was missing that. Thank you.
> > 
> > Hmm then in struct slab, page->compound_head and slab->list_head (or
> > slab->rcu_head) has same offset. And list_head / rcu_head both store pointers.
> > 
> > then it has a alignment requirement. (address saved in list_head/rcu_head
> > should be multiple of 2)
> > 
> > Anyway, it was required long time before this patch,
> > so it is not a problem for this patch.
> 
> Yes, that's why there's an assert that the list_heads all line up.  This
> requirement will go away if we do get separately allocated memory
> descriptors (because that bottom bit is no longer PageTail).

Yeah, we don't need to care that if we separately allocate memory for
struct slab.

Thanks,
Hyeonggon.

Re: [PATCH v2 31/33] mm/sl*b: Differentiate struct slab fields by sl*b implementations

[Matthew Wilcox]

On Fri, Dec 10, 2021 at 07:26:11PM +0100, Vlastimil Babka wrote:
> > Because SLUB and SLAB sets slab->slab_cache = NULL (to set page->mapping = NULL),
> 
> Hm, now that you mention it, maybe it would be better to do a
> "folio->mapping = NULL" instead as we now have a more clearer view where we
> operate on struct slab, and where we transition between that and a plain
> folio. This is IMHO part of preparing the folio for freeing, not a struct
> slab cleanup as struct slab doesn't need this cleanup.

Yes, I did that as part of "mm/slub: Convert slab freeing to struct slab"
in my original series:

-       __ClearPageSlabPfmemalloc(page);
+       __slab_clear_pfmemalloc(slab);
        __ClearPageSlab(page);
-       /* In union with page->mapping where page allocator expects NULL */
-       page->slab_cache = NULL;
+       page->mapping = NULL;

Re: [PATCH v2 31/33] mm/sl*b: Differentiate struct slab fields by sl*b implementations

[Hyeonggon Yoo]

On Sat, Dec 11, 2021 at 04:23:47PM +0000, Matthew Wilcox wrote:
> On Fri, Dec 10, 2021 at 07:26:11PM +0100, Vlastimil Babka wrote:
> > > Because SLUB and SLAB sets slab->slab_cache = NULL (to set page->mapping = NULL),
> > 
> > Hm, now that you mention it, maybe it would be better to do a
> > "folio->mapping = NULL" instead as we now have a more clearer view where we
> > operate on struct slab, and where we transition between that and a plain
> > folio. This is IMHO part of preparing the folio for freeing, not a struct
> > slab cleanup as struct slab doesn't need this cleanup.
> 
> Yes, I did that as part of "mm/slub: Convert slab freeing to struct slab"
> in my original series:
> 
> -       __ClearPageSlabPfmemalloc(page);
> +       __slab_clear_pfmemalloc(slab);
>         __ClearPageSlab(page);
> -       /* In union with page->mapping where page allocator expects NULL */
> -       page->slab_cache = NULL;
> +       page->mapping = NULL;

Didn't know your original patch series did it already.
Vlastimil, would you update that patch?

[PATCH] mm/slob: Remove unnecessary page_mapcount_reset() function call

[Hyeonggon Yoo]

After commit f1ac9059ca34 ("mm/sl*b: Differentiate struct slab fields
by sl*b implementations"), we can reorder fields of struct slab
depending on slab allocator.

For now, page_mapcount_reset() is called because page->_mapcount and
slab->units have same offset. But this is not necessary for
struct slab. Use unused field for units instead.

Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
---
 mm/slab.h | 4 ++--
 mm/slob.c | 1 -
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/mm/slab.h b/mm/slab.h
index 90d7fceba470..dd0480149d38 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -50,8 +50,8 @@ struct slab {
 	struct list_head slab_list;
 	void * __unused_1;
 	void *freelist;		/* first free block */
-	void * __unused_2;
-	int units;
+	long units;
+	unsigned int __unused_2;
 
 #else
 #error "Unexpected slab allocator configured"
diff --git a/mm/slob.c b/mm/slob.c
index 39b651b3e6e7..7b2d2c7d69cc 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -404,7 +404,6 @@ static void slob_free(void *block, int size)
 			clear_slob_page_free(sp);
 		spin_unlock_irqrestore(&slob_lock, flags);
 		__ClearPageSlab(slab_page(sp));
-		page_mapcount_reset(slab_page(sp));
 		slob_free_pages(b, 0);
 		return;
 	}
-- 
2.30.2

Re: [PATCH] mm/slob: Remove unnecessary page_mapcount_reset() function call

[Vlastimil Babka]

On 12/12/21 07:52, Hyeonggon Yoo wrote:
> After commit f1ac9059ca34 ("mm/sl*b: Differentiate struct slab fields
> by sl*b implementations"), we can reorder fields of struct slab
> depending on slab allocator.
> 
> For now, page_mapcount_reset() is called because page->_mapcount and
> slab->units have same offset. But this is not necessary for
> struct slab. Use unused field for units instead.
> 
> Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

Will add to the series, thanks!

> ---
>  mm/slab.h | 4 ++--
>  mm/slob.c | 1 -
>  2 files changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/slab.h b/mm/slab.h
> index 90d7fceba470..dd0480149d38 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -50,8 +50,8 @@ struct slab {
>  	struct list_head slab_list;
>  	void * __unused_1;
>  	void *freelist;		/* first free block */
> -	void * __unused_2;
> -	int units;
> +	long units;
> +	unsigned int __unused_2;
>  
>  #else
>  #error "Unexpected slab allocator configured"
> diff --git a/mm/slob.c b/mm/slob.c
> index 39b651b3e6e7..7b2d2c7d69cc 100644
> --- a/mm/slob.c
> +++ b/mm/slob.c
> @@ -404,7 +404,6 @@ static void slob_free(void *block, int size)
>  			clear_slob_page_free(sp);
>  		spin_unlock_irqrestore(&slob_lock, flags);
>  		__ClearPageSlab(slab_page(sp));
> -		page_mapcount_reset(slab_page(sp));
>  		slob_free_pages(b, 0);
>  		return;
>  	}

[PATCH v2 32/33] mm/slub: Simplify struct slab slabs field definition

[Vlastimil Babka]

Before commit b47291ef02b0 ("mm, slub: change percpu partial accounting from
objects to pages") we had to fit two integer fields into a native word size, so
we used short int on 32-bit and int on 64-bit via #ifdef. After that commit
there is only one integer field, so we can simply define it as int everywhere.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slab.h | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/mm/slab.h b/mm/slab.h
index 8c5a8c005896..ee4344a44987 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -27,11 +27,7 @@ struct slab {
 		struct rcu_head rcu_head;
 		struct {
 			struct slab *next;
-#ifdef CONFIG_64BIT
 			int slabs;	/* Nr of slabs left */
-#else
-			short int slabs;
-#endif
 		};
 	};
 	struct kmem_cache *slab_cache;
-- 
2.33.1

Re: [PATCH v2 32/33] mm/slub: Simplify struct slab slabs field definition

[Johannes Weiner]

On Wed, Dec 01, 2021 at 07:15:09PM +0100, Vlastimil Babka wrote:
> Before commit b47291ef02b0 ("mm, slub: change percpu partial accounting from
> objects to pages") we had to fit two integer fields into a native word size, so
> we used short int on 32-bit and int on 64-bit via #ifdef. After that commit
> there is only one integer field, so we can simply define it as int everywhere.
> 
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

[PATCH v2 33/33] mm/slub: Define struct slab fields for CONFIG_SLUB_CPU_PARTIAL only when enabled

[Vlastimil Babka]

The fields 'next' and 'slabs' are only used when CONFIG_SLUB_CPU_PARTIAL is
enabled. We can put their definition to #ifdef to prevent accidental use when
disabled.

Currenlty show_slab_objects() and slabs_cpu_partial_show() contain code
accessing the slabs field that's effectively dead with
CONFIG_SLUB_CPU_PARTIAL=n through the wrappers slub_percpu_partial() and
slub_percpu_partial_read_once(), but to prevent a compile error, we need to
hide all this code behind #ifdef.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slab.h | 2 ++
 mm/slub.c | 8 ++++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/mm/slab.h b/mm/slab.h
index ee4344a44987..46ea468b29aa 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -25,10 +25,12 @@ struct slab {
 	union {
 		struct list_head slab_list;
 		struct rcu_head rcu_head;
+#ifdef CONFIG_SLUB_CPU_PARTIAL
 		struct {
 			struct slab *next;
 			int slabs;	/* Nr of slabs left */
 		};
+#endif
 	};
 	struct kmem_cache *slab_cache;
 	/* Double-word boundary */
diff --git a/mm/slub.c b/mm/slub.c
index 58f0d499a293..978d754d0ada 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5256,6 +5256,7 @@ static ssize_t show_slab_objects(struct kmem_cache *s,
 			total += x;
 			nodes[node] += x;
 
+#ifdef CONFIG_SLUB_CPU_PARTIAL
 			slab = slub_percpu_partial_read_once(c);
 			if (slab) {
 				node = slab_nid(slab);
@@ -5268,6 +5269,7 @@ static ssize_t show_slab_objects(struct kmem_cache *s,
 				total += x;
 				nodes[node] += x;
 			}
+#endif
 		}
 	}
 
@@ -5467,9 +5469,10 @@ static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
 {
 	int objects = 0;
 	int slabs = 0;
-	int cpu;
+	int cpu __maybe_unused;
 	int len = 0;
 
+#ifdef CONFIG_SLUB_CPU_PARTIAL
 	for_each_online_cpu(cpu) {
 		struct slab *slab;
 
@@ -5478,12 +5481,13 @@ static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
 		if (slab)
 			slabs += slab->slabs;
 	}
+#endif
 
 	/* Approximate half-full slabs, see slub_set_cpu_partial() */
 	objects = (slabs * oo_objects(s->oo)) / 2;
 	len += sysfs_emit_at(buf, len, "%d(%d)", objects, slabs);
 
-#ifdef CONFIG_SMP
+#if defined(CONFIG_SLUB_CPU_PARTIAL) && defined(CONFIG_SMP)
 	for_each_online_cpu(cpu) {
 		struct slab *slab;
 
-- 
2.33.1

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Vlastimil Babka]

On 12/1/21 19:14, Vlastimil Babka wrote:
> Folks from non-slab subsystems are Cc'd only to patches affecting them, and
> this cover letter.
> 
> Series also available in git, based on 5.16-rc3:
> https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2

I have pushed a v3, but not going to resent immediately to avoid unnecessary
spamming, the differences is just that some patches are removed and other
reordered, so the current v2 posting should be still sufficient for on-list
review:

https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v3r1

patch 29/33 iommu: Use put_pages_list
- removed as this version is broken and Robin Murphy has meanwhile
incorporated it partially to his series:
https://lore.kernel.org/lkml/cover.1637671820.git.robin.murphy@arm.com/

patch 30/33 mm: Remove slab from struct page
- removed and postponed for later as this can be only be applied after the
iommu use of page.freelist is resolved

patch 27/33 zsmalloc: Stop using slab fields in struct page
patch 28/33 bootmem: Use page->index instead of page->freelist
- moved towards the end of series, to further separate the part that adjusts
non-slab users of slab fields towards removing those fields from struct page.

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Vlastimil Babka]

On 12/1/21 19:14, Vlastimil Babka wrote:
> Folks from non-slab subsystems are Cc'd only to patches affecting them, and
> this cover letter.
> 
> Series also available in git, based on 5.16-rc3:
> https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2

Pushed a new branch slab-struct-slab-v3r3 with accumulated fixes and small tweaks
and a new patch from Hyeonggon Yoo on top. To avoid too much spam, here's a range diff:

 1:  10b656f9eb1e =  1:  10b656f9eb1e mm: add virt_to_folio() and folio_address()
 2:  5e6ad846acf1 =  2:  5e6ad846acf1 mm/slab: Dissolve slab_map_pages() in its caller
 3:  48d4e9407aa0 =  3:  48d4e9407aa0 mm/slub: Make object_err() static
 4:  fe1e19081321 =  4:  fe1e19081321 mm: Split slab into its own type
 5:  af7fd46fbb9b =  5:  af7fd46fbb9b mm: Add account_slab() and unaccount_slab()
 6:  7ed088d601d9 =  6:  7ed088d601d9 mm: Convert virt_to_cache() to use struct slab
 7:  1d41188b9401 =  7:  1d41188b9401 mm: Convert __ksize() to struct slab
 8:  5d9d1231461f !  8:  8fd22e0b086e mm: Use struct slab in kmem_obj_info()
    @@ Commit message
         slab type instead of the page type, we make it obvious that this can
         only be called for slabs.
     
    +    [ vbabka@suse.cz: also convert the related kmem_valid_obj() to folios ]
    +
         Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
         Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
     
    @@ mm/slab.h: struct kmem_obj_info {
      #endif /* MM_SLAB_H */
     
      ## mm/slab_common.c ##
    +@@ mm/slab_common.c: bool slab_is_available(void)
    +  */
    + bool kmem_valid_obj(void *object)
    + {
    +-	struct page *page;
    ++	struct folio *folio;
    + 
    + 	/* Some arches consider ZERO_SIZE_PTR to be a valid address. */
    + 	if (object < (void *)PAGE_SIZE || !virt_addr_valid(object))
    + 		return false;
    +-	page = virt_to_head_page(object);
    +-	return PageSlab(page);
    ++	folio = virt_to_folio(object);
    ++	return folio_test_slab(folio);
    + }
    + EXPORT_SYMBOL_GPL(kmem_valid_obj);
    + 
     @@ mm/slab_common.c: void kmem_dump_obj(void *object)
      {
      	char *cp = IS_ENABLED(CONFIG_MMU) ? "" : "/vmalloc";
    @@ mm/slub.c: int __kmem_cache_shutdown(struct kmem_cache *s)
      	objp = base + s->size * objnr;
      	kpp->kp_objp = objp;
     -	if (WARN_ON_ONCE(objp < base || objp >= base + page->objects * s->size || (objp - base) % s->size) ||
    -+	if (WARN_ON_ONCE(objp < base || objp >= base + slab->objects * s->size || (objp - base) % s->size) ||
    ++	if (WARN_ON_ONCE(objp < base || objp >= base + slab->objects * s->size
    ++			 || (objp - base) % s->size) ||
      	    !(s->flags & SLAB_STORE_USER))
      		return;
      #ifdef CONFIG_SLUB_DEBUG
 9:  3aef771be335 !  9:  c97e73c3b6c2 mm: Convert check_heap_object() to use struct slab
    @@ mm/slab.h: struct kmem_obj_info {
     +#else
     +static inline
     +void __check_heap_object(const void *ptr, unsigned long n,
    -+			 const struct slab *slab, bool to_user) { }
    ++			 const struct slab *slab, bool to_user)
    ++{
    ++}
     +#endif
     +
      #endif /* MM_SLAB_H */
10:  2253e45e6bef = 10:  da05e0f7179c mm/slub: Convert detached_freelist to use a struct slab
11:  f28202bc27ba = 11:  383887e77104 mm/slub: Convert kfree() to use a struct slab
12:  31b58b1e914f = 12:  c46be093c637 mm/slub: Convert __slab_lock() and __slab_unlock() to struct slab
13:  636406a3ad59 = 13:  49dbbf917052 mm/slub: Convert print_page_info() to print_slab_info()
14:  3b49efda3b6f = 14:  4bb0c932156a mm/slub: Convert alloc_slab_page() to return a struct slab
15:  61a195526d3b ! 15:  4b9761b5cfab mm/slub: Convert __free_slab() to use struct slab
    @@ mm/slub.c: static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int n
      
     -	__ClearPageSlabPfmemalloc(page);
     -	__ClearPageSlab(page);
    +-	/* In union with page->mapping where page allocator expects NULL */
    +-	page->slab_cache = NULL;
     +	__slab_clear_pfmemalloc(slab);
     +	__folio_clear_slab(folio);
    - 	/* In union with page->mapping where page allocator expects NULL */
    --	page->slab_cache = NULL;
    -+	slab->slab_cache = NULL;
    ++	folio->mapping = NULL;
      	if (current->reclaim_state)
      		current->reclaim_state->reclaimed_slab += pages;
     -	unaccount_slab(page_slab(page), order, s);
16:  987c7ed31580 = 16:  f384ec918065 mm/slub: Convert pfmemalloc_match() to take a struct slab
17:  cc742564237e ! 17:  06738ade4e17 mm/slub: Convert most struct page to struct slab by spatch
    @@ Commit message
     
         // Options: --include-headers --no-includes --smpl-spacing include/linux/slub_def.h mm/slub.c
         // Note: needs coccinelle 1.1.1 to avoid breaking whitespace, and ocaml for the
    -    // embedded script script
    +    // embedded script
     
         // build list of functions to exclude from applying the next rule
         @initialize:ocaml@
18:  b45acac9aace = 18:  1a4f69a4cced mm/slub: Finish struct page to struct slab conversion
19:  76c3eeb39684 ! 19:  1d62d706e884 mm/slab: Convert kmem_getpages() and kmem_freepages() to struct slab
    @@ mm/slab.c: slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nod
     -	__ClearPageSlabPfmemalloc(page);
     -	__ClearPageSlab(page);
     -	page_mapcount_reset(page);
    +-	/* In union with page->mapping where page allocator expects NULL */
    +-	page->slab_cache = NULL;
     +	BUG_ON(!folio_test_slab(folio));
     +	__slab_clear_pfmemalloc(slab);
     +	__folio_clear_slab(folio);
     +	page_mapcount_reset(folio_page(folio, 0));
    - 	/* In union with page->mapping where page allocator expects NULL */
    --	page->slab_cache = NULL;
    -+	slab->slab_cache = NULL;
    ++	folio->mapping = NULL;
      
      	if (current->reclaim_state)
      		current->reclaim_state->reclaimed_slab += 1 << order;
20:  ed6144dbebce ! 20:  fd4c3aabacd3 mm/slab: Convert most struct page to struct slab by spatch
    @@ Commit message
     
         // Options: --include-headers --no-includes --smpl-spacing mm/slab.c
         // Note: needs coccinelle 1.1.1 to avoid breaking whitespace, and ocaml for the
    -    // embedded script script
    +    // embedded script
     
         // build list of functions for applying the next rule
         @initialize:ocaml@
21:  17fb81e601e6 = 21:  b59720b2edba mm/slab: Finish struct page to struct slab conversion
22:  4e8d1faebc24 ! 22:  65ced071c3e7 mm: Convert struct page to struct slab in functions used by other subsystems
    @@ Commit message
           ,...)
     
         Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
    +    Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
         Cc: Julia Lawall <julia.lawall@inria.fr>
         Cc: Luis Chamberlain <mcgrof@kernel.org>
         Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
23:  eefa12e18a92 = 23:  c9c8dee01e5d mm/memcg: Convert slab objcgs from struct page to struct slab
24:  fa5ba4107ce2 ! 24:  def731137335 mm/slob: Convert SLOB to use struct slab
    @@ Metadata
     Author: Matthew Wilcox (Oracle) <willy@infradead.org>
     
      ## Commit message ##
    -    mm/slob: Convert SLOB to use struct slab
    +    mm/slob: Convert SLOB to use struct slab and struct folio
     
    -    Use struct slab throughout the slob allocator.
    +    Use struct slab throughout the slob allocator. Where non-slab page can appear
    +    use struct folio instead of struct page.
     
         [ vbabka@suse.cz: don't introduce wrappers for PageSlobFree in mm/slab.h just
           for the single callers being wrappers in mm/slob.c ]
     
    +    [ Hyeonggon Yoo <42.hyeyoo@gmail.com>: fix NULL pointer deference ]
    +
         Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
         Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
     
      ## mm/slob.c ##
    +@@
    +  * If kmalloc is asked for objects of PAGE_SIZE or larger, it calls
    +  * alloc_pages() directly, allocating compound pages so the page order
    +  * does not have to be separately tracked.
    +- * These objects are detected in kfree() because PageSlab()
    ++ * These objects are detected in kfree() because folio_test_slab()
    +  * is false for them.
    +  *
    +  * SLAB is emulated on top of SLOB by simply calling constructors and
     @@ mm/slob.c: static LIST_HEAD(free_slob_large);
      /*
       * slob_page_free: true for pages on free_slob_pages list.
    @@ mm/slob.c: static void *slob_page_alloc(struct page *sp, size_t size, int align,
      							int align_offset)
      {
     -	struct page *sp;
    ++	struct folio *folio;
     +	struct slab *sp;
      	struct list_head *slob_list;
      	slob_t *b = NULL;
    @@ mm/slob.c: static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
      			return NULL;
     -		sp = virt_to_page(b);
     -		__SetPageSlab(sp);
    -+		sp = virt_to_slab(b);
    -+		__SetPageSlab(slab_page(sp));
    ++		folio = virt_to_folio(b);
    ++		__folio_set_slab(folio);
    ++		sp = folio_slab(folio);
      
      		spin_lock_irqsave(&slob_lock, flags);
      		sp->units = SLOB_UNITS(PAGE_SIZE);
    @@ mm/slob.c: static void slob_free(void *block, int size)
      		spin_unlock_irqrestore(&slob_lock, flags);
     -		__ClearPageSlab(sp);
     -		page_mapcount_reset(sp);
    -+		__ClearPageSlab(slab_page(sp));
    ++		__folio_clear_slab(slab_folio(sp));
     +		page_mapcount_reset(slab_page(sp));
      		slob_free_pages(b, 0);
      		return;
      	}
    +@@ mm/slob.c: EXPORT_SYMBOL(__kmalloc_node_track_caller);
    + 
    + void kfree(const void *block)
    + {
    +-	struct page *sp;
    ++	struct folio *sp;
    + 
    + 	trace_kfree(_RET_IP_, block);
    + 
    +@@ mm/slob.c: void kfree(const void *block)
    + 		return;
    + 	kmemleak_free(block);
    + 
    +-	sp = virt_to_page(block);
    +-	if (PageSlab(sp)) {
    ++	sp = virt_to_folio(block);
    ++	if (folio_test_slab(sp)) {
    + 		int align = max_t(size_t, ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
    + 		unsigned int *m = (unsigned int *)(block - align);
    + 		slob_free(m, *m + align);
    + 	} else {
    +-		unsigned int order = compound_order(sp);
    +-		mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE_B,
    ++		unsigned int order = folio_order(sp);
    ++
    ++		mod_node_page_state(folio_pgdat(sp), NR_SLAB_UNRECLAIMABLE_B,
    + 				    -(PAGE_SIZE << order));
    +-		__free_pages(sp, order);
    ++		__free_pages(folio_page(sp, 0), order);
    + 
    + 	}
    + }
25:  aa4f573a4c96 ! 25:  466b9fb1f6e5 mm/kasan: Convert to struct folio and struct slab
    @@ Commit message
     
         Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
         Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
    +    Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
         Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
         Cc: Alexander Potapenko <glider@google.com>
         Cc: Andrey Konovalov <andreyknvl@gmail.com>
26:  67b7966d2fb6 = 26:  b8159ae8e5cd mm/kfence: Convert kfence_guarded_alloc() to struct slab
31:  d64dfe49c1e7 ! 27:  4525180926f9 mm/sl*b: Differentiate struct slab fields by sl*b implementations
    @@ Commit message
         possible.
     
         This should also prevent accidental use of fields that don't exist in given
    -    implementation. Before this patch virt_to_cache() and and cache_from_obj() was
    -    visible for SLOB (albeit not used), although it relies on the slab_cache field
    +    implementation. Before this patch virt_to_cache() and cache_from_obj() were
    +    visible for SLOB (albeit not used), although they rely on the slab_cache field
         that isn't set by SLOB. With this patch it's now a compile error, so these
         functions are now hidden behind #ifndef CONFIG_SLOB.
     
    @@ mm/kfence/core.c: static void *kfence_guarded_alloc(struct kmem_cache *cache, si
     -		slab->s_mem = addr;
     +#if defined(CONFIG_SLUB)
     +	slab->objects = 1;
    -+#elif defined (CONFIG_SLAB)
    ++#elif defined(CONFIG_SLAB)
     +	slab->s_mem = addr;
     +#endif
      
    @@ mm/slab.h
     +
     +#if defined(CONFIG_SLAB)
     +
    -+	union {
    -+		struct list_head slab_list;
    + 	union {
    + 		struct list_head slab_list;
    +-		struct {	/* Partial pages */
     +		struct rcu_head rcu_head;
     +	};
     +	struct kmem_cache *slab_cache;
     +	void *freelist;	/* array of free object indexes */
    -+	void * s_mem;	/* first object */
    ++	void *s_mem;	/* first object */
     +	unsigned int active;
     +
     +#elif defined(CONFIG_SLUB)
     +
    - 	union {
    - 		struct list_head slab_list;
    --		struct {	/* Partial pages */
    ++	union {
    ++		struct list_head slab_list;
     +		struct rcu_head rcu_head;
     +		struct {
      			struct slab *next;
    @@ mm/slab.h: struct slab {
     +#elif defined(CONFIG_SLOB)
     +
     +	struct list_head slab_list;
    -+	void * __unused_1;
    ++	void *__unused_1;
     +	void *freelist;		/* first free block */
    -+	void * __unused_2;
    ++	void *__unused_2;
     +	int units;
     +
     +#else
    @@ mm/slab.h: struct slab {
      #ifdef CONFIG_MEMCG
      	unsigned long memcg_data;
     @@ mm/slab.h: struct slab {
    - 	static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl))
      SLAB_MATCH(flags, __page_flags);
      SLAB_MATCH(compound_head, slab_list);	/* Ensure bit 0 is clear */
    + SLAB_MATCH(slab_list, slab_list);
     +#ifndef CONFIG_SLOB
      SLAB_MATCH(rcu_head, rcu_head);
    + SLAB_MATCH(slab_cache, slab_cache);
    ++#endif
    ++#ifdef CONFIG_SLAB
    + SLAB_MATCH(s_mem, s_mem);
    + SLAB_MATCH(active, active);
     +#endif
      SLAB_MATCH(_refcount, __page_refcount);
      #ifdef CONFIG_MEMCG
32:  0abf87bae67e = 28:  94b78948d53f mm/slub: Simplify struct slab slabs field definition
33:  813c304f18e4 = 29:  f5261e6375f0 mm/slub: Define struct slab fields for CONFIG_SLUB_CPU_PARTIAL only when enabled
27:  ebce4b5b5ced ! 30:  1414e8c87de6 zsmalloc: Stop using slab fields in struct page
    @@ Commit message
     
         Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
         Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
    -    Cc: Minchan Kim <minchan@kernel.org>
    +    Acked-by: Minchan Kim <minchan@kernel.org>
         Cc: Nitin Gupta <ngupta@vflare.org>
         Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
     
28:  f124425ae7de = 31:  8a3cda6b38eb bootmem: Use page->index instead of page->freelist
29:  82da48c73b2e <  -:  ------------ iommu: Use put_pages_list
30:  181e16dfefbb <  -:  ------------ mm: Remove slab from struct page
 -:  ------------ > 32:  91e069ba116b mm/slob: Remove unnecessary page_mapcount_reset() function call

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Hyeonggon Yoo]

On Tue, Dec 14, 2021 at 01:57:22PM +0100, Vlastimil Babka wrote:
> On 12/1/21 19:14, Vlastimil Babka wrote:
> > Folks from non-slab subsystems are Cc'd only to patches affecting them, and
> > this cover letter.
> > 
> > Series also available in git, based on 5.16-rc3:
> > https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2
> 
> Pushed a new branch slab-struct-slab-v3r3 with accumulated fixes and small tweaks
> and a new patch from Hyeonggon Yoo on top. To avoid too much spam, here's a range diff:
> 

Hello Vlastimil, Thank you for nice work.
I'm going to review and test new version soon in free time.

Btw, I gave you some review and test tags and seems to be missing in new
series. Did I do review/test process wrongly? It's first time to review
patches so please let me know if I did it wrongly.

--
Thank you.
Hyeonggon.

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Vlastimil Babka]

On 12/14/21 15:38, Hyeonggon Yoo wrote:
> On Tue, Dec 14, 2021 at 01:57:22PM +0100, Vlastimil Babka wrote:
>> On 12/1/21 19:14, Vlastimil Babka wrote:
>> > Folks from non-slab subsystems are Cc'd only to patches affecting them, and
>> > this cover letter.
>> > 
>> > Series also available in git, based on 5.16-rc3:
>> > https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2
>> 
>> Pushed a new branch slab-struct-slab-v3r3 with accumulated fixes and small tweaks
>> and a new patch from Hyeonggon Yoo on top. To avoid too much spam, here's a range diff:
>> 
> 
> Hello Vlastimil, Thank you for nice work.
> I'm going to review and test new version soon in free time.

Thanks!

> Btw, I gave you some review and test tags and seems to be missing in new
> series. Did I do review/test process wrongly? It's first time to review
> patches so please let me know if I did it wrongly.

You did right, sorry! I didn't include them as those were for patches that I
was additionally changing after your review/test and the decision what is
substantial change enough to need a new test/review is often fuzzy. So if
you can recheck the new versions it would be great and then I will pick that
up, thanks!

> --
> Thank you.
> Hyeonggon.

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Hyeonggon Yoo]

On Tue, Dec 14, 2021 at 03:43:35PM +0100, Vlastimil Babka wrote:
> On 12/14/21 15:38, Hyeonggon Yoo wrote:
> > On Tue, Dec 14, 2021 at 01:57:22PM +0100, Vlastimil Babka wrote:
> >> On 12/1/21 19:14, Vlastimil Babka wrote:
> >> > Folks from non-slab subsystems are Cc'd only to patches affecting them, and
> >> > this cover letter.
> >> > 
> >> > Series also available in git, based on 5.16-rc3:
> >> > https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2
> >> 
> >> Pushed a new branch slab-struct-slab-v3r3 with accumulated fixes and small tweaks
> >> and a new patch from Hyeonggon Yoo on top. To avoid too much spam, here's a range diff:
> >> 
> > 
> > Hello Vlastimil, Thank you for nice work.
> > I'm going to review and test new version soon in free time.
> 
> Thanks!
> 

You're welcome!

> > Btw, I gave you some review and test tags and seems to be missing in new
> > series. Did I do review/test process wrongly? It's first time to review
> > patches so please let me know if I did it wrongly.
> 
> You did right, sorry! I didn't include them as those were for patches that I
> was additionally changing after your review/test and the decision what is
> substantial change enough to need a new test/review is often fuzzy. 

Ah, Okay. review/test becomes invalid after some changing.
that's okay. I was just unfamiliar with the process. Thank you!

> So if you can recheck the new versions it would be great and then I will pick that
> up, thanks!

Okay. I'll new versions.

> 
> > --
> > Thank you.
> > Hyeonggon.
> 

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Roman Gushchin]

On Tue, Dec 14, 2021 at 01:57:22PM +0100, Vlastimil Babka wrote:
> On 12/1/21 19:14, Vlastimil Babka wrote:
> > Folks from non-slab subsystems are Cc'd only to patches affecting them, and
> > this cover letter.
> > 
> > Series also available in git, based on 5.16-rc3:
> > https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2
> 
> Pushed a new branch slab-struct-slab-v3r3 with accumulated fixes and small tweaks
> and a new patch from Hyeonggon Yoo on top. To avoid too much spam, here's a range diff:

Hi Vlastimil!

I've started to review this patchset (btw, a really nice work, I like
the resulting code way more). Because I'm looking at v3 and I don't have
the whole v2 in my mailbox, here is what I've now:

* mm: add virt_to_folio() and folio_address()
Reviewed-by: Roman Gushchin <guro@fb.com>

* mm/slab: Dissolve slab_map_pages() in its caller
Reviewed-by: Roman Gushchin <guro@fb.com>

* mm/slub: Make object_err() static
Reviewed-by: Roman Gushchin <guro@fb.com>

* mm: Split slab into its own type
1) Shouldn't SLAB_MATCH() macro use struct folio instead of struct page for the
comparison?
2) page_slab() is used only in kasan and only in one place, so maybe it's better
to not introduce it as a generic helper?
Other than that
Reviewed-by: Roman Gushchin <guro@fb.com>

* mm: Add account_slab() and unaccount_slab()
1) maybe change the title to convert/replace instead of add?
2) maybe move later changes to memcg_alloc_page_obj_cgroups() to this patch?
Reviewed-by: Roman Gushchin <guro@fb.com>

* mm: Convert virt_to_cache() to use struct slab
Reviewed-by: Roman Gushchin <guro@fb.com>

* mm: Convert __ksize() to struct slab
It looks like certain parts of __ksize() can be merged between slab, slub and slob?
Reviewed-by: Roman Gushchin <guro@fb.com>

* mm: Use struct slab in kmem_obj_info()
Reviewed-by: Roman Gushchin <guro@fb.com>


I'll try to finish reviewing the patchset until the  end of the week.

Thanks!

Roman

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Roman Gushchin]

On Tue, Dec 14, 2021 at 05:03:12PM -0800, Roman Gushchin wrote:
> On Tue, Dec 14, 2021 at 01:57:22PM +0100, Vlastimil Babka wrote:
> > On 12/1/21 19:14, Vlastimil Babka wrote:
> > > Folks from non-slab subsystems are Cc'd only to patches affecting them, and
> > > this cover letter.
> > > 
> > > Series also available in git, based on 5.16-rc3:
> > > https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2
> > 
> > Pushed a new branch slab-struct-slab-v3r3 with accumulated fixes and small tweaks
> > and a new patch from Hyeonggon Yoo on top. To avoid too much spam, here's a range diff:
> 
> Hi Vlastimil!
> 
> I've started to review this patchset (btw, a really nice work, I like
> the resulting code way more). Because I'm looking at v3 and I don't have
> the whole v2 in my mailbox, here is what I've now:
> 
> * mm: add virt_to_folio() and folio_address()
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm/slab: Dissolve slab_map_pages() in its caller
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm/slub: Make object_err() static
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm: Split slab into its own type
> 1) Shouldn't SLAB_MATCH() macro use struct folio instead of struct page for the
> comparison?
> 2) page_slab() is used only in kasan and only in one place, so maybe it's better
> to not introduce it as a generic helper?
> Other than that
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm: Add account_slab() and unaccount_slab()
> 1) maybe change the title to convert/replace instead of add?
> 2) maybe move later changes to memcg_alloc_page_obj_cgroups() to this patch?
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm: Convert virt_to_cache() to use struct slab
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm: Convert __ksize() to struct slab
> It looks like certain parts of __ksize() can be merged between slab, slub and slob?
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm: Use struct slab in kmem_obj_info()
> Reviewed-by: Roman Gushchin <guro@fb.com>

Part 2:

* mm: Convert check_heap_object() to use struct slab
Reviewed-by: Roman Gushchin <guro@fb.com>

* mm/slub: Convert detached_freelist to use a struct slab
How about to convert free_nonslab_page() to free_nonslab_folio()?
And maybe rename it to something like free_large_kmalloc()?
If I'm not missing something, large kmallocs is the only way how we can end up
there with a !slab folio/page.

* mm/slub: Convert kfree() to use a struct slab
Reviewed-by: Roman Gushchin <guro@fb.com>

* mm/slub: Convert __slab_lock() and __slab_unlock() to struct slab
Reviewed-by: Roman Gushchin <guro@fb.com>

* mm/slub: Convert print_page_info() to print_slab_info()
Do we really need to explicitly convert slab_folio()'s result to (struct folio *)?
Reviewed-by: Roman Gushchin <guro@fb.com>

* mm/slub: Convert alloc_slab_page() to return a struct slab
Reviewed-by: Roman Gushchin <guro@fb.com>

* mm/slub: Convert __free_slab() to use struct slab
Reviewed-by: Roman Gushchin <guro@fb.com>

* mm/slub: Convert pfmemalloc_match() to take a struct slab
Cool! Removing pfmemalloc_unsafe() is really nice.
Reviewed-by: Roman Gushchin <guro@fb.com>

* mm/slub: Convert most struct page to struct slab by spatch
Reviewed-by: Roman Gushchin <guro@fb.com>

* mm/slub: Finish struct page to struct slab conversion
Reviewed-by: Roman Gushchin <guro@fb.com>

* mm/slab: Convert kmem_getpages() and kmem_freepages() to struct slab
Reviewed-by: Roman Gushchin <guro@fb.com>

* mm/slab: Convert most struct page to struct slab by spatch

Another patch with the same title? Rebase error?

* mm/slab: Finish struct page to struct slab conversion

And this one too?


Thanks!

Roman

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Vlastimil Babka]

On 12/16/21 00:38, Roman Gushchin wrote:
> On Tue, Dec 14, 2021 at 05:03:12PM -0800, Roman Gushchin wrote:
>> On Tue, Dec 14, 2021 at 01:57:22PM +0100, Vlastimil Babka wrote:
>> > On 12/1/21 19:14, Vlastimil Babka wrote:
>> > > Folks from non-slab subsystems are Cc'd only to patches affecting them, and
>> > > this cover letter.
>> > > 
>> > > Series also available in git, based on 5.16-rc3:
>> > > https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2
>> > 
>> > Pushed a new branch slab-struct-slab-v3r3 with accumulated fixes and small tweaks
>> > and a new patch from Hyeonggon Yoo on top. To avoid too much spam, here's a range diff:
>> 
>> Hi Vlastimil!
>> 
>> I've started to review this patchset (btw, a really nice work, I like
>> the resulting code way more). Because I'm looking at v3 and I don't have

Thanks a lot, Roman!

...

> 
> * mm/slab: Convert most struct page to struct slab by spatch
> 
> Another patch with the same title? Rebase error?
> 
> * mm/slab: Finish struct page to struct slab conversion
> 
> And this one too?

No, these are for mm/slab.c, the previous were for mm/slub.c :)

> 
> Thanks!
> 
> Roman

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Vlastimil Babka]

On 12/16/21 00:38, Roman Gushchin wrote:
> Part 2:
> 
> * mm: Convert check_heap_object() to use struct slab
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm/slub: Convert detached_freelist to use a struct slab
> How about to convert free_nonslab_page() to free_nonslab_folio()?
> And maybe rename it to something like free_large_kmalloc()?
> If I'm not missing something, large kmallocs is the only way how we can end up
> there with a !slab folio/page.

Good point, thanks! But did at as part of the following patch, where it fits
logically better.

> * mm/slub: Convert kfree() to use a struct slab
> Reviewed-by: Roman Gushchin <guro@fb.com>

Didn't add your tag because of the addition of free_large_kmalloc() change.

> * mm/slub: Convert __slab_lock() and __slab_unlock() to struct slab
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm/slub: Convert print_page_info() to print_slab_info()
> Do we really need to explicitly convert slab_folio()'s result to (struct folio *)?

Unfortunately yes, as long as folio_flags() don't take const struct folio *,
which will need some yak shaving.

> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm/slub: Convert alloc_slab_page() to return a struct slab
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm/slub: Convert __free_slab() to use struct slab
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm/slub: Convert pfmemalloc_match() to take a struct slab
> Cool! Removing pfmemalloc_unsafe() is really nice.
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm/slub: Convert most struct page to struct slab by spatch
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm/slub: Finish struct page to struct slab conversion
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm/slab: Convert kmem_getpages() and kmem_freepages() to struct slab
> Reviewed-by: Roman Gushchin <guro@fb.com>

Thanks again!

> * mm/slab: Convert most struct page to struct slab by spatch
> 
> Another patch with the same title? Rebase error?
> 
> * mm/slab: Finish struct page to struct slab conversion
> 
> And this one too?
> 
> 
> Thanks!
> 
> Roman

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Matthew Wilcox]

On Mon, Dec 20, 2021 at 01:47:54AM +0100, Vlastimil Babka wrote:
> > * mm/slub: Convert print_page_info() to print_slab_info()
> > Do we really need to explicitly convert slab_folio()'s result to (struct folio *)?
> 
> Unfortunately yes, as long as folio_flags() don't take const struct folio *,
> which will need some yak shaving.

In case anyone's interested ...

folio_flags calls VM_BUG_ON_PGFLAGS() which would need its second
argument to be const.

That means dump_page() needs to take a const struct page, which
means __dump_page() needs its argument to be const.

That calls ...

is_migrate_cma_page()
page_mapping()
page_mapcount()
page_ref_count()
page_to_pgoff()
page_to_pfn()
hpage_pincount_available()
head_compound_mapcount()
head_compound_pincount()
compound_order()
PageKsm()
PageAnon()
PageCompound()

... and at that point, I ran out of motivation to track down some parts
of this tarbaby that could be fixed.  I did do:

    mm: constify page_count and page_ref_count
    mm: constify get_pfnblock_flags_mask and get_pfnblock_migratetype
    mm: make compound_head const-preserving
    mm/page_owner: constify dump_page_owner

so some of those are already done.  But a lot of them just need to be
done at the same time.  For example, page_mapping() calls
folio_mapping() which calls folio_test_slab() which calls folio_flags(),
so dump_page() and page_mapping() need to be done at the same time.

One bit that could be broken off easily (I think ...) is PageTransTail()
PageTail(), PageCompound(), PageHuge(), page_to_pgoff() and
page_to_index().  One wrinkle is needed a temporary
TESTPAGEFLAGS_FALSE_CONST.  But I haven't tried it yet.

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Vlastimil Babka]

On 12/15/21 02:03, Roman Gushchin wrote:
> On Tue, Dec 14, 2021 at 01:57:22PM +0100, Vlastimil Babka wrote:
>> On 12/1/21 19:14, Vlastimil Babka wrote:
>> > Folks from non-slab subsystems are Cc'd only to patches affecting them, and
>> > this cover letter.
>> > 
>> > Series also available in git, based on 5.16-rc3:
>> > https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2
>> 
>> Pushed a new branch slab-struct-slab-v3r3 with accumulated fixes and small tweaks
>> and a new patch from Hyeonggon Yoo on top. To avoid too much spam, here's a range diff:
> 
> Hi Vlastimil!
> 
> I've started to review this patchset (btw, a really nice work, I like
> the resulting code way more). Because I'm looking at v3 and I don't have
> the whole v2 in my mailbox, here is what I've now:

Thanks a lot, Roman!

> * mm: add virt_to_folio() and folio_address()
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm/slab: Dissolve slab_map_pages() in its caller
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm/slub: Make object_err() static
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm: Split slab into its own type
> 1) Shouldn't SLAB_MATCH() macro use struct folio instead of struct page for the
> comparison?

Folio doesn't have define most of the fields, and matching some to page and
others to folio seems like unnecessary complication. Maybe as part of the
final struct page cleanup when the slab fields are gone from struct page,
the rest could all be in folio - I'll check once we get there.

> 2) page_slab() is used only in kasan and only in one place, so maybe it's better
> to not introduce it as a generic helper?

Yeah that's the case after the series, but as part of the incremental steps,
page_slab() gets used in many places. I'll consider removing it on top though.

> Other than that
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm: Add account_slab() and unaccount_slab()
> 1) maybe change the title to convert/replace instead of add?

Done.

> 2) maybe move later changes to memcg_alloc_page_obj_cgroups() to this patch?

Maybe possible, but that would distort the series more than I'd like to at
this rc6 time.

> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm: Convert virt_to_cache() to use struct slab
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm: Convert __ksize() to struct slab
> It looks like certain parts of __ksize() can be merged between slab, slub and slob?
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> * mm: Use struct slab in kmem_obj_info()
> Reviewed-by: Roman Gushchin <guro@fb.com>
> 
> 
> I'll try to finish reviewing the patchset until the  end of the week.
> 
> Thanks!
> 
> Roman

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Hyeonggon Yoo]

On Tue, Dec 14, 2021 at 01:57:22PM +0100, Vlastimil Babka wrote:
> On 12/1/21 19:14, Vlastimil Babka wrote:
> > Folks from non-slab subsystems are Cc'd only to patches affecting them, and
> > this cover letter.
> > 
> > Series also available in git, based on 5.16-rc3:
> > https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2
> 
> Pushed a new branch slab-struct-slab-v3r3 with accumulated fixes and small tweaks
> and a new patch from Hyeonggon Yoo on top. To avoid too much spam, here's a range diff:

Reviewing the whole patch series takes longer than I thought.
I'll try to review and test rest of patches when I have time.

I added Tested-by if kernel builds okay and kselftests
does not break the kernel on my machine.
(with CONFIG_SLAB/SLUB/SLOB depending on the patch),
Let me know me if you know better way to test a patch.

# mm/slub: Define struct slab fields for CONFIG_SLUB_CPU_PARTIAL only when enabled

Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

Comment:
Works on both SLUB_CPU_PARTIAL and !SLUB_CPU_PARTIAL.
btw, do we need slabs_cpu_partial attribute when we don't use
cpu partials? (!SLUB_CPU_PARTIAL)

# mm/slub: Simplify struct slab slabs field definition
Comment:

This is how struct page looks on the top of v3r3 branch:
struct page {
[...]
                struct {        /* slab, slob and slub */
                        union {
                                struct list_head slab_list;
                                struct {        /* Partial pages */
                                        struct page *next;
#ifdef CONFIG_64BIT
                                        int pages;      /* Nr of pages left */
#else
                                        short int pages;
#endif
                                };
                        };
[...]

It's not consistent with struct slab.
I think this is because "mm: Remove slab from struct page" was dropped.
Would you update some of patches?

# mm/sl*b: Differentiate struct slab fields by sl*b implementations
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Works SL[AUO]B on my machine and makes code much better.

# mm/slob: Convert SLOB to use struct slab and struct folio
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
It still works fine on SLOB.

# mm/slab: Convert kmem_getpages() and kmem_freepages() to struct slab
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

# mm/slub: Convert __free_slab() to use struct slab
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

Thanks,
Hyeonggon.

> 
>  1:  10b656f9eb1e =  1:  10b656f9eb1e mm: add virt_to_folio() and folio_address()
>  2:  5e6ad846acf1 =  2:  5e6ad846acf1 mm/slab: Dissolve slab_map_pages() in its caller
>  3:  48d4e9407aa0 =  3:  48d4e9407aa0 mm/slub: Make object_err() static
>  4:  fe1e19081321 =  4:  fe1e19081321 mm: Split slab into its own type
>  5:  af7fd46fbb9b =  5:  af7fd46fbb9b mm: Add account_slab() and unaccount_slab()
>  6:  7ed088d601d9 =  6:  7ed088d601d9 mm: Convert virt_to_cache() to use struct slab
>  7:  1d41188b9401 =  7:  1d41188b9401 mm: Convert __ksize() to struct slab
>  8:  5d9d1231461f !  8:  8fd22e0b086e mm: Use struct slab in kmem_obj_info()
>     @@ Commit message
>          slab type instead of the page type, we make it obvious that this can
>          only be called for slabs.
>      
>     +    [ vbabka@suse.cz: also convert the related kmem_valid_obj() to folios ]
>     +
>          Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
>          Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
>      
>     @@ mm/slab.h: struct kmem_obj_info {
>       #endif /* MM_SLAB_H */
>      
>       ## mm/slab_common.c ##
>     +@@ mm/slab_common.c: bool slab_is_available(void)
>     +  */
>     + bool kmem_valid_obj(void *object)
>     + {
>     +-	struct page *page;
>     ++	struct folio *folio;
>     + 
>     + 	/* Some arches consider ZERO_SIZE_PTR to be a valid address. */
>     + 	if (object < (void *)PAGE_SIZE || !virt_addr_valid(object))
>     + 		return false;
>     +-	page = virt_to_head_page(object);
>     +-	return PageSlab(page);
>     ++	folio = virt_to_folio(object);
>     ++	return folio_test_slab(folio);
>     + }
>     + EXPORT_SYMBOL_GPL(kmem_valid_obj);
>     + 
>      @@ mm/slab_common.c: void kmem_dump_obj(void *object)
>       {
>       	char *cp = IS_ENABLED(CONFIG_MMU) ? "" : "/vmalloc";
>     @@ mm/slub.c: int __kmem_cache_shutdown(struct kmem_cache *s)
>       	objp = base + s->size * objnr;
>       	kpp->kp_objp = objp;
>      -	if (WARN_ON_ONCE(objp < base || objp >= base + page->objects * s->size || (objp - base) % s->size) ||
>     -+	if (WARN_ON_ONCE(objp < base || objp >= base + slab->objects * s->size || (objp - base) % s->size) ||
>     ++	if (WARN_ON_ONCE(objp < base || objp >= base + slab->objects * s->size
>     ++			 || (objp - base) % s->size) ||
>       	    !(s->flags & SLAB_STORE_USER))
>       		return;
>       #ifdef CONFIG_SLUB_DEBUG
>  9:  3aef771be335 !  9:  c97e73c3b6c2 mm: Convert check_heap_object() to use struct slab
>     @@ mm/slab.h: struct kmem_obj_info {
>      +#else
>      +static inline
>      +void __check_heap_object(const void *ptr, unsigned long n,
>     -+			 const struct slab *slab, bool to_user) { }
>     ++			 const struct slab *slab, bool to_user)
>     ++{
>     ++}
>      +#endif
>      +
>       #endif /* MM_SLAB_H */
> 10:  2253e45e6bef = 10:  da05e0f7179c mm/slub: Convert detached_freelist to use a struct slab
> 11:  f28202bc27ba = 11:  383887e77104 mm/slub: Convert kfree() to use a struct slab
> 12:  31b58b1e914f = 12:  c46be093c637 mm/slub: Convert __slab_lock() and __slab_unlock() to struct slab
> 13:  636406a3ad59 = 13:  49dbbf917052 mm/slub: Convert print_page_info() to print_slab_info()
> 14:  3b49efda3b6f = 14:  4bb0c932156a mm/slub: Convert alloc_slab_page() to return a struct slab
> 15:  61a195526d3b ! 15:  4b9761b5cfab mm/slub: Convert __free_slab() to use struct slab
>     @@ mm/slub.c: static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int n
>       
>      -	__ClearPageSlabPfmemalloc(page);
>      -	__ClearPageSlab(page);
>     +-	/* In union with page->mapping where page allocator expects NULL */
>     +-	page->slab_cache = NULL;
>      +	__slab_clear_pfmemalloc(slab);
>      +	__folio_clear_slab(folio);
>     - 	/* In union with page->mapping where page allocator expects NULL */
>     --	page->slab_cache = NULL;
>     -+	slab->slab_cache = NULL;
>     ++	folio->mapping = NULL;
>       	if (current->reclaim_state)
>       		current->reclaim_state->reclaimed_slab += pages;
>      -	unaccount_slab(page_slab(page), order, s);
> 16:  987c7ed31580 = 16:  f384ec918065 mm/slub: Convert pfmemalloc_match() to take a struct slab
> 17:  cc742564237e ! 17:  06738ade4e17 mm/slub: Convert most struct page to struct slab by spatch
>     @@ Commit message
>      
>          // Options: --include-headers --no-includes --smpl-spacing include/linux/slub_def.h mm/slub.c
>          // Note: needs coccinelle 1.1.1 to avoid breaking whitespace, and ocaml for the
>     -    // embedded script script
>     +    // embedded script
>      
>          // build list of functions to exclude from applying the next rule
>          @initialize:ocaml@
> 18:  b45acac9aace = 18:  1a4f69a4cced mm/slub: Finish struct page to struct slab conversion
> 19:  76c3eeb39684 ! 19:  1d62d706e884 mm/slab: Convert kmem_getpages() and kmem_freepages() to struct slab
>     @@ mm/slab.c: slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nod
>      -	__ClearPageSlabPfmemalloc(page);
>      -	__ClearPageSlab(page);
>      -	page_mapcount_reset(page);
>     +-	/* In union with page->mapping where page allocator expects NULL */
>     +-	page->slab_cache = NULL;
>      +	BUG_ON(!folio_test_slab(folio));
>      +	__slab_clear_pfmemalloc(slab);
>      +	__folio_clear_slab(folio);
>      +	page_mapcount_reset(folio_page(folio, 0));
>     - 	/* In union with page->mapping where page allocator expects NULL */
>     --	page->slab_cache = NULL;
>     -+	slab->slab_cache = NULL;
>     ++	folio->mapping = NULL;
>       
>       	if (current->reclaim_state)
>       		current->reclaim_state->reclaimed_slab += 1 << order;
> 20:  ed6144dbebce ! 20:  fd4c3aabacd3 mm/slab: Convert most struct page to struct slab by spatch
>     @@ Commit message
>      
>          // Options: --include-headers --no-includes --smpl-spacing mm/slab.c
>          // Note: needs coccinelle 1.1.1 to avoid breaking whitespace, and ocaml for the
>     -    // embedded script script
>     +    // embedded script
>      
>          // build list of functions for applying the next rule
>          @initialize:ocaml@
> 21:  17fb81e601e6 = 21:  b59720b2edba mm/slab: Finish struct page to struct slab conversion
> 22:  4e8d1faebc24 ! 22:  65ced071c3e7 mm: Convert struct page to struct slab in functions used by other subsystems
>     @@ Commit message
>            ,...)
>      
>          Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
>     +    Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
>          Cc: Julia Lawall <julia.lawall@inria.fr>
>          Cc: Luis Chamberlain <mcgrof@kernel.org>
>          Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
> 23:  eefa12e18a92 = 23:  c9c8dee01e5d mm/memcg: Convert slab objcgs from struct page to struct slab
> 24:  fa5ba4107ce2 ! 24:  def731137335 mm/slob: Convert SLOB to use struct slab
>     @@ Metadata
>      Author: Matthew Wilcox (Oracle) <willy@infradead.org>
>      
>       ## Commit message ##
>     -    mm/slob: Convert SLOB to use struct slab
>     +    mm/slob: Convert SLOB to use struct slab and struct folio
>      
>     -    Use struct slab throughout the slob allocator.
>     +    Use struct slab throughout the slob allocator. Where non-slab page can appear
>     +    use struct folio instead of struct page.
>      
>          [ vbabka@suse.cz: don't introduce wrappers for PageSlobFree in mm/slab.h just
>            for the single callers being wrappers in mm/slob.c ]
>      
>     +    [ Hyeonggon Yoo <42.hyeyoo@gmail.com>: fix NULL pointer deference ]
>     +
>          Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
>          Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
>      
>       ## mm/slob.c ##
>     +@@
>     +  * If kmalloc is asked for objects of PAGE_SIZE or larger, it calls
>     +  * alloc_pages() directly, allocating compound pages so the page order
>     +  * does not have to be separately tracked.
>     +- * These objects are detected in kfree() because PageSlab()
>     ++ * These objects are detected in kfree() because folio_test_slab()
>     +  * is false for them.
>     +  *
>     +  * SLAB is emulated on top of SLOB by simply calling constructors and
>      @@ mm/slob.c: static LIST_HEAD(free_slob_large);
>       /*
>        * slob_page_free: true for pages on free_slob_pages list.
>     @@ mm/slob.c: static void *slob_page_alloc(struct page *sp, size_t size, int align,
>       							int align_offset)
>       {
>      -	struct page *sp;
>     ++	struct folio *folio;
>      +	struct slab *sp;
>       	struct list_head *slob_list;
>       	slob_t *b = NULL;
>     @@ mm/slob.c: static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
>       			return NULL;
>      -		sp = virt_to_page(b);
>      -		__SetPageSlab(sp);
>     -+		sp = virt_to_slab(b);
>     -+		__SetPageSlab(slab_page(sp));
>     ++		folio = virt_to_folio(b);
>     ++		__folio_set_slab(folio);
>     ++		sp = folio_slab(folio);
>       
>       		spin_lock_irqsave(&slob_lock, flags);
>       		sp->units = SLOB_UNITS(PAGE_SIZE);
>     @@ mm/slob.c: static void slob_free(void *block, int size)
>       		spin_unlock_irqrestore(&slob_lock, flags);
>      -		__ClearPageSlab(sp);
>      -		page_mapcount_reset(sp);
>     -+		__ClearPageSlab(slab_page(sp));
>     ++		__folio_clear_slab(slab_folio(sp));
>      +		page_mapcount_reset(slab_page(sp));
>       		slob_free_pages(b, 0);
>       		return;
>       	}
>     +@@ mm/slob.c: EXPORT_SYMBOL(__kmalloc_node_track_caller);
>     + 
>     + void kfree(const void *block)
>     + {
>     +-	struct page *sp;
>     ++	struct folio *sp;
>     + 
>     + 	trace_kfree(_RET_IP_, block);
>     + 
>     +@@ mm/slob.c: void kfree(const void *block)
>     + 		return;
>     + 	kmemleak_free(block);
>     + 
>     +-	sp = virt_to_page(block);
>     +-	if (PageSlab(sp)) {
>     ++	sp = virt_to_folio(block);
>     ++	if (folio_test_slab(sp)) {
>     + 		int align = max_t(size_t, ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
>     + 		unsigned int *m = (unsigned int *)(block - align);
>     + 		slob_free(m, *m + align);
>     + 	} else {
>     +-		unsigned int order = compound_order(sp);
>     +-		mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE_B,
>     ++		unsigned int order = folio_order(sp);
>     ++
>     ++		mod_node_page_state(folio_pgdat(sp), NR_SLAB_UNRECLAIMABLE_B,
>     + 				    -(PAGE_SIZE << order));
>     +-		__free_pages(sp, order);
>     ++		__free_pages(folio_page(sp, 0), order);
>     + 
>     + 	}
>     + }
> 25:  aa4f573a4c96 ! 25:  466b9fb1f6e5 mm/kasan: Convert to struct folio and struct slab
>     @@ Commit message
>      
>          Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
>          Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
>     +    Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
>          Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
>          Cc: Alexander Potapenko <glider@google.com>
>          Cc: Andrey Konovalov <andreyknvl@gmail.com>
> 26:  67b7966d2fb6 = 26:  b8159ae8e5cd mm/kfence: Convert kfence_guarded_alloc() to struct slab
> 31:  d64dfe49c1e7 ! 27:  4525180926f9 mm/sl*b: Differentiate struct slab fields by sl*b implementations
>     @@ Commit message
>          possible.
>      
>          This should also prevent accidental use of fields that don't exist in given
>     -    implementation. Before this patch virt_to_cache() and and cache_from_obj() was
>     -    visible for SLOB (albeit not used), although it relies on the slab_cache field
>     +    implementation. Before this patch virt_to_cache() and cache_from_obj() were
>     +    visible for SLOB (albeit not used), although they rely on the slab_cache field
>          that isn't set by SLOB. With this patch it's now a compile error, so these
>          functions are now hidden behind #ifndef CONFIG_SLOB.
>      
>     @@ mm/kfence/core.c: static void *kfence_guarded_alloc(struct kmem_cache *cache, si
>      -		slab->s_mem = addr;
>      +#if defined(CONFIG_SLUB)
>      +	slab->objects = 1;
>     -+#elif defined (CONFIG_SLAB)
>     ++#elif defined(CONFIG_SLAB)
>      +	slab->s_mem = addr;
>      +#endif
>       
>     @@ mm/slab.h
>      +
>      +#if defined(CONFIG_SLAB)
>      +
>     -+	union {
>     -+		struct list_head slab_list;
>     + 	union {
>     + 		struct list_head slab_list;
>     +-		struct {	/* Partial pages */
>      +		struct rcu_head rcu_head;
>      +	};
>      +	struct kmem_cache *slab_cache;
>      +	void *freelist;	/* array of free object indexes */
>     -+	void * s_mem;	/* first object */
>     ++	void *s_mem;	/* first object */
>      +	unsigned int active;
>      +
>      +#elif defined(CONFIG_SLUB)
>      +
>     - 	union {
>     - 		struct list_head slab_list;
>     --		struct {	/* Partial pages */
>     ++	union {
>     ++		struct list_head slab_list;
>      +		struct rcu_head rcu_head;
>      +		struct {
>       			struct slab *next;
>     @@ mm/slab.h: struct slab {
>      +#elif defined(CONFIG_SLOB)
>      +
>      +	struct list_head slab_list;
>     -+	void * __unused_1;
>     ++	void *__unused_1;
>      +	void *freelist;		/* first free block */
>     -+	void * __unused_2;
>     ++	void *__unused_2;
>      +	int units;
>      +
>      +#else
>     @@ mm/slab.h: struct slab {
>       #ifdef CONFIG_MEMCG
>       	unsigned long memcg_data;
>      @@ mm/slab.h: struct slab {
>     - 	static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl))
>       SLAB_MATCH(flags, __page_flags);
>       SLAB_MATCH(compound_head, slab_list);	/* Ensure bit 0 is clear */
>     + SLAB_MATCH(slab_list, slab_list);
>      +#ifndef CONFIG_SLOB
>       SLAB_MATCH(rcu_head, rcu_head);
>     + SLAB_MATCH(slab_cache, slab_cache);
>     ++#endif
>     ++#ifdef CONFIG_SLAB
>     + SLAB_MATCH(s_mem, s_mem);
>     + SLAB_MATCH(active, active);
>      +#endif
>       SLAB_MATCH(_refcount, __page_refcount);
>       #ifdef CONFIG_MEMCG
> 32:  0abf87bae67e = 28:  94b78948d53f mm/slub: Simplify struct slab slabs field definition
> 33:  813c304f18e4 = 29:  f5261e6375f0 mm/slub: Define struct slab fields for CONFIG_SLUB_CPU_PARTIAL only when enabled
> 27:  ebce4b5b5ced ! 30:  1414e8c87de6 zsmalloc: Stop using slab fields in struct page
>     @@ Commit message
>      
>          Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
>          Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
>     -    Cc: Minchan Kim <minchan@kernel.org>
>     +    Acked-by: Minchan Kim <minchan@kernel.org>
>          Cc: Nitin Gupta <ngupta@vflare.org>
>          Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
>      
> 28:  f124425ae7de = 31:  8a3cda6b38eb bootmem: Use page->index instead of page->freelist
> 29:  82da48c73b2e <  -:  ------------ iommu: Use put_pages_list
> 30:  181e16dfefbb <  -:  ------------ mm: Remove slab from struct page
>  -:  ------------ > 32:  91e069ba116b mm/slob: Remove unnecessary page_mapcount_reset() function call

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Vlastimil Babka]

On 12/16/21 16:00, Hyeonggon Yoo wrote:
> On Tue, Dec 14, 2021 at 01:57:22PM +0100, Vlastimil Babka wrote:
>> On 12/1/21 19:14, Vlastimil Babka wrote:
>> > Folks from non-slab subsystems are Cc'd only to patches affecting them, and
>> > this cover letter.
>> > 
>> > Series also available in git, based on 5.16-rc3:
>> > https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2
>> 
>> Pushed a new branch slab-struct-slab-v3r3 with accumulated fixes and small tweaks
>> and a new patch from Hyeonggon Yoo on top. To avoid too much spam, here's a range diff:
> 
> Reviewing the whole patch series takes longer than I thought.
> I'll try to review and test rest of patches when I have time.
> 
> I added Tested-by if kernel builds okay and kselftests
> does not break the kernel on my machine.
> (with CONFIG_SLAB/SLUB/SLOB depending on the patch),

Thanks!

> Let me know me if you know better way to test a patch.

Testing on your machine is just fine.

> # mm/slub: Define struct slab fields for CONFIG_SLUB_CPU_PARTIAL only when enabled
> 
> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> 
> Comment:
> Works on both SLUB_CPU_PARTIAL and !SLUB_CPU_PARTIAL.
> btw, do we need slabs_cpu_partial attribute when we don't use
> cpu partials? (!SLUB_CPU_PARTIAL)

The sysfs attribute? Yeah we should be consistent to userspace expecting to
read it (even with zeroes), regardless of config.

> # mm/slub: Simplify struct slab slabs field definition
> Comment:
> 
> This is how struct page looks on the top of v3r3 branch:
> struct page {
> [...]
>                 struct {        /* slab, slob and slub */
>                         union {
>                                 struct list_head slab_list;
>                                 struct {        /* Partial pages */
>                                         struct page *next;
> #ifdef CONFIG_64BIT
>                                         int pages;      /* Nr of pages left */
> #else
>                                         short int pages;
> #endif
>                                 };
>                         };
> [...]
> 
> It's not consistent with struct slab.

Hm right. But as we don't actually use the struct page version anymore, and
it's not one of the fields checked by SLAB_MATCH(), we can ignore this.

> I think this is because "mm: Remove slab from struct page" was dropped.

That was just postponed until iommu changes are in. Matthew mentioned those
might be merged too, so that final cleanup will happen too and take care of
the discrepancy above, so no need for extra churn to address it speficially.

> Would you update some of patches?
> 
> # mm/sl*b: Differentiate struct slab fields by sl*b implementations
> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> Works SL[AUO]B on my machine and makes code much better.
> 
> # mm/slob: Convert SLOB to use struct slab and struct folio
> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> It still works fine on SLOB.
> 
> # mm/slab: Convert kmem_getpages() and kmem_freepages() to struct slab
> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> 
> # mm/slub: Convert __free_slab() to use struct slab
> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> 
> Thanks,
> Hyeonggon.

Thanks again,
Vlastimil

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Robin Murphy]

On 2021-12-20 23:58, Vlastimil Babka wrote:
> On 12/16/21 16:00, Hyeonggon Yoo wrote:
>> On Tue, Dec 14, 2021 at 01:57:22PM +0100, Vlastimil Babka wrote:
>>> On 12/1/21 19:14, Vlastimil Babka wrote:
>>>> Folks from non-slab subsystems are Cc'd only to patches affecting them, and
>>>> this cover letter.
>>>>
>>>> Series also available in git, based on 5.16-rc3:
>>>> https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2
>>>
>>> Pushed a new branch slab-struct-slab-v3r3 with accumulated fixes and small tweaks
>>> and a new patch from Hyeonggon Yoo on top. To avoid too much spam, here's a range diff:
>>
>> Reviewing the whole patch series takes longer than I thought.
>> I'll try to review and test rest of patches when I have time.
>>
>> I added Tested-by if kernel builds okay and kselftests
>> does not break the kernel on my machine.
>> (with CONFIG_SLAB/SLUB/SLOB depending on the patch),
> 
> Thanks!
> 
>> Let me know me if you know better way to test a patch.
> 
> Testing on your machine is just fine.
> 
>> # mm/slub: Define struct slab fields for CONFIG_SLUB_CPU_PARTIAL only when enabled
>>
>> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
>> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
>>
>> Comment:
>> Works on both SLUB_CPU_PARTIAL and !SLUB_CPU_PARTIAL.
>> btw, do we need slabs_cpu_partial attribute when we don't use
>> cpu partials? (!SLUB_CPU_PARTIAL)
> 
> The sysfs attribute? Yeah we should be consistent to userspace expecting to
> read it (even with zeroes), regardless of config.
> 
>> # mm/slub: Simplify struct slab slabs field definition
>> Comment:
>>
>> This is how struct page looks on the top of v3r3 branch:
>> struct page {
>> [...]
>>                  struct {        /* slab, slob and slub */
>>                          union {
>>                                  struct list_head slab_list;
>>                                  struct {        /* Partial pages */
>>                                          struct page *next;
>> #ifdef CONFIG_64BIT
>>                                          int pages;      /* Nr of pages left */
>> #else
>>                                          short int pages;
>> #endif
>>                                  };
>>                          };
>> [...]
>>
>> It's not consistent with struct slab.
> 
> Hm right. But as we don't actually use the struct page version anymore, and
> it's not one of the fields checked by SLAB_MATCH(), we can ignore this.
> 
>> I think this is because "mm: Remove slab from struct page" was dropped.
> 
> That was just postponed until iommu changes are in. Matthew mentioned those
> might be merged too, so that final cleanup will happen too and take care of
> the discrepancy above, so no need for extra churn to address it speficially.

FYI the IOMMU changes are now queued in linux-next, so if all goes well 
you might be able to sneak that final patch in too.

Robin.

> 
>> Would you update some of patches?
>>
>> # mm/sl*b: Differentiate struct slab fields by sl*b implementations
>> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
>> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
>> Works SL[AUO]B on my machine and makes code much better.
>>
>> # mm/slob: Convert SLOB to use struct slab and struct folio
>> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
>> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
>> It still works fine on SLOB.
>>
>> # mm/slab: Convert kmem_getpages() and kmem_freepages() to struct slab
>> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
>> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
>>
>> # mm/slub: Convert __free_slab() to use struct slab
>> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
>> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
>>
>> Thanks,
>> Hyeonggon.
> 
> Thanks again,
> Vlastimil
> _______________________________________________
> iommu mailing list
> iommu@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/iommu

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Hyeonggon Yoo]

On Tue, Dec 21, 2021 at 12:58:14AM +0100, Vlastimil Babka wrote:
> On 12/16/21 16:00, Hyeonggon Yoo wrote:
> > On Tue, Dec 14, 2021 at 01:57:22PM +0100, Vlastimil Babka wrote:
> >> On 12/1/21 19:14, Vlastimil Babka wrote:
> >> > Folks from non-slab subsystems are Cc'd only to patches affecting them, and
> >> > this cover letter.
> >> > 
> >> > Series also available in git, based on 5.16-rc3:
> >> > https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2
> >> 
> >> Pushed a new branch slab-struct-slab-v3r3 with accumulated fixes and small tweaks
> >> and a new patch from Hyeonggon Yoo on top. To avoid too much spam, here's a range diff:
> > 
> > Reviewing the whole patch series takes longer than I thought.
> > I'll try to review and test rest of patches when I have time.
> > 
> > I added Tested-by if kernel builds okay and kselftests
> > does not break the kernel on my machine.
> > (with CONFIG_SLAB/SLUB/SLOB depending on the patch),
> 
> Thanks!
>

:)

> > Let me know me if you know better way to test a patch.
> 
> Testing on your machine is just fine.
>

Good!

> > # mm/slub: Define struct slab fields for CONFIG_SLUB_CPU_PARTIAL only when enabled
> > 
> > Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > 
> > Comment:
> > Works on both SLUB_CPU_PARTIAL and !SLUB_CPU_PARTIAL.
> > btw, do we need slabs_cpu_partial attribute when we don't use
> > cpu partials? (!SLUB_CPU_PARTIAL)
> 
> The sysfs attribute? Yeah we should be consistent to userspace expecting to
> read it (even with zeroes), regardless of config.
> 

I thought entirely disabling the attribute is simpler,
But okay If it should be exposed even if it's always zero.

> > # mm/slub: Simplify struct slab slabs field definition
> > Comment:
> > 
> > This is how struct page looks on the top of v3r3 branch:
> > struct page {
> > [...]
> >                 struct {        /* slab, slob and slub */
> >                         union {
> >                                 struct list_head slab_list;
> >                                 struct {        /* Partial pages */
> >                                         struct page *next;
> > #ifdef CONFIG_64BIT
> >                                         int pages;      /* Nr of pages left */
> > #else
> >                                         short int pages;
> > #endif
> >                                 };
> >                         };
> > [...]
> > 
> > It's not consistent with struct slab.
> 
> Hm right. But as we don't actually use the struct page version anymore, and
> it's not one of the fields checked by SLAB_MATCH(), we can ignore this.
>

Yeah this is not a big problem. just mentioned this because 
it looked weird and I didn't know when the patch "mm: Remove slab from struct page"
will come back.

> > I think this is because "mm: Remove slab from struct page" was dropped.
>
> That was just postponed until iommu changes are in. Matthew mentioned those
> might be merged too, so that final cleanup will happen too and take care of
> the discrepancy above, so no need for extra churn to address it speficially.
> 

Okay it seems no extra work needed until the iommu changes are in!

BTW, in the patch (that I sent) ("mm/slob: Remove unnecessary page_mapcount_reset()
function call"), it refers commit 4525180926f9  ("mm/sl*b: Differentiate struct slab fields by
sl*b implementations"). But the commit hash 4525180926f9 changed after the
tree has been changed.

It will be nice to write a script to handle situations like this.

> > Would you update some of patches?
> > 
> > # mm/sl*b: Differentiate struct slab fields by sl*b implementations
> > Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > Works SL[AUO]B on my machine and makes code much better.
> > 
> > # mm/slob: Convert SLOB to use struct slab and struct folio
> > Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > It still works fine on SLOB.
> > 
> > # mm/slab: Convert kmem_getpages() and kmem_freepages() to struct slab
> > Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> >
> > # mm/slub: Convert __free_slab() to use struct slab
> > Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> > 
> > Thanks,
> > Hyeonggon.
> 
> Thanks again,
> Vlastimil

Have a nice day, thanks!
Hyeonggon.

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Vlastimil Babka]

On 12/14/21 13:57, Vlastimil Babka wrote:
> On 12/1/21 19:14, Vlastimil Babka wrote:
>> Folks from non-slab subsystems are Cc'd only to patches affecting them, and
>> this cover letter.
>>
>> Series also available in git, based on 5.16-rc3:
>> https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2
> 
> Pushed a new branch slab-struct-slab-v3r3 with accumulated fixes and small tweaks
> and a new patch from Hyeonggon Yoo on top. To avoid too much spam, here's a range diff:

Hi, I've pushed another update branch slab-struct_slab-v4r1, and also to
-next. I've shortened git commit log lines to make checkpatch happier,
so no range-diff as it would be too long. I believe it would be useless
spam to post the whole series now, shortly before xmas, so I will do it
at rc8 time, to hopefully collect remaining reviews. But if anyone wants
a mailed version, I can do that.

Changes in v4:
- rebase to 5.16-rc6 to avoid a conflict with mainline
- collect acks/reviews/tested-by from Johannes, Roman, Hyeonggon Yoo -
thanks!
- in patch "mm/slub: Convert detached_freelist to use a struct slab"
renamed free_nonslab_page() to free_large_kmalloc() and use folio there,
as suggested by Roman
- in "mm/memcg: Convert slab objcgs from struct page to struct slab"
change one caller of slab_objcgs_check() to slab_objcgs() as suggested
by Johannes, realize the other caller should be also changed, and remove
slab_objcgs_check() completely.

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Hyeonggon Yoo]

On Wed, Dec 22, 2021 at 05:56:50PM +0100, Vlastimil Babka wrote:
> On 12/14/21 13:57, Vlastimil Babka wrote:
> > On 12/1/21 19:14, Vlastimil Babka wrote:
> >> Folks from non-slab subsystems are Cc'd only to patches affecting them, and
> >> this cover letter.
> >>
> >> Series also available in git, based on 5.16-rc3:
> >> https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2
> > 
> > Pushed a new branch slab-struct-slab-v3r3 with accumulated fixes and small tweaks
> > and a new patch from Hyeonggon Yoo on top. To avoid too much spam, here's a range diff:
> 
> Hi, I've pushed another update branch slab-struct_slab-v4r1, and also to
> -next. I've shortened git commit log lines to make checkpatch happier,
> so no range-diff as it would be too long. I believe it would be useless
> spam to post the whole series now, shortly before xmas, so I will do it
> at rc8 time, to hopefully collect remaining reviews. But if anyone wants
> a mailed version, I can do that.

Hello Vlastimil, Merry Christmas!
This is part 2 of reviewing/testing patches.

# mm/kasan: Convert to struct folio and struct slab
I'm not familiar with kasan yet but kasan runs well on my machine and
kasan's bug report functionality too works fine.
Tested-by: Hyeongogn Yoo <42.hyeyoo@gmail.com>

# mm: Convert struct page to struct slab in functions used by other subsystems
I'm not familiar with kasan, but to ask:
Does ____kasan_slab_free detect invalid free if someone frees
an object that is not allocated from slab?

@@ -341,7 +341,7 @@ static inline bool ____kasan_slab_free(struct kmem_cache *cache, void *object,
-       if (unlikely(nearest_obj(cache, virt_to_head_page(object), object) !=
+       if (unlikely(nearest_obj(cache, virt_to_slab(object), object) !=
            object)) {
                kasan_report_invalid_free(tagged_object, ip);
                return true;

I'm asking this because virt_to_slab() will return NULL if folio_test_slab()
returns false. That will cause NULL pointer dereference in nearest_obj.
I don't think this change is intended.

This makes me think some of virt_to_head_page() -> virt_to_slab()
conversion need to be reviewed with caution.

# mm/slab: Finish struct page to struct slab conversion
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

# mm/slab: Convert most struct page to struct slab by spatch
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

I'll come back with part 3 :)
Enjoy your Christmas!
Hyeonggon

> Changes in v4:
> - rebase to 5.16-rc6 to avoid a conflict with mainline
> - collect acks/reviews/tested-by from Johannes, Roman, Hyeonggon Yoo -
> thanks!
> - in patch "mm/slub: Convert detached_freelist to use a struct slab"
> renamed free_nonslab_page() to free_large_kmalloc() and use folio there,
> as suggested by Roman
> - in "mm/memcg: Convert slab objcgs from struct page to struct slab"
> change one caller of slab_objcgs_check() to slab_objcgs() as suggested
> by Johannes, realize the other caller should be also changed, and remove
> slab_objcgs_check() completely.

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Matthew Wilcox]

On Sat, Dec 25, 2021 at 09:16:55AM +0000, Hyeonggon Yoo wrote:
> # mm: Convert struct page to struct slab in functions used by other subsystems
> I'm not familiar with kasan, but to ask:
> Does ____kasan_slab_free detect invalid free if someone frees
> an object that is not allocated from slab?
> 
> @@ -341,7 +341,7 @@ static inline bool ____kasan_slab_free(struct kmem_cache *cache, void *object,
> -       if (unlikely(nearest_obj(cache, virt_to_head_page(object), object) !=
> +       if (unlikely(nearest_obj(cache, virt_to_slab(object), object) !=
>             object)) {
>                 kasan_report_invalid_free(tagged_object, ip);
>                 return true;
> 
> I'm asking this because virt_to_slab() will return NULL if folio_test_slab()
> returns false. That will cause NULL pointer dereference in nearest_obj.
> I don't think this change is intended.

You need to track down how this could happen.  As far as I can tell,
it's always called when we know the object is part of a slab.  That's
where the cachep pointer is deduced from.

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Hyeonggon Yoo]

On Sat, Dec 25, 2021 at 05:53:23PM +0000, Matthew Wilcox wrote:
> On Sat, Dec 25, 2021 at 09:16:55AM +0000, Hyeonggon Yoo wrote:
> > # mm: Convert struct page to struct slab in functions used by other subsystems
> > I'm not familiar with kasan, but to ask:
> > Does ____kasan_slab_free detect invalid free if someone frees
> > an object that is not allocated from slab?
> > 
> > @@ -341,7 +341,7 @@ static inline bool ____kasan_slab_free(struct kmem_cache *cache, void *object,
> > -       if (unlikely(nearest_obj(cache, virt_to_head_page(object), object) !=
> > +       if (unlikely(nearest_obj(cache, virt_to_slab(object), object) !=
> >             object)) {
> >                 kasan_report_invalid_free(tagged_object, ip);
> >                 return true;
> > 
> > I'm asking this because virt_to_slab() will return NULL if folio_test_slab()
> > returns false. That will cause NULL pointer dereference in nearest_obj.
> > I don't think this change is intended.
> 
> You need to track down how this could happen.  As far as I can tell,
> it's always called when we know the object is part of a slab.  That's
> where the cachep pointer is deduced from.

Thank you Matthew, you are right. I read the code too narrowly.
when we call kasan hooks, we know that the object is allocated from
the slab cache. (through cache_from_obj)

I'll review that patch again in part 3!

Thanks,
Hyeonggon

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Hyeonggon Yoo]

On Wed, Dec 22, 2021 at 05:56:50PM +0100, Vlastimil Babka wrote:
> On 12/14/21 13:57, Vlastimil Babka wrote:
> > On 12/1/21 19:14, Vlastimil Babka wrote:
> >> Folks from non-slab subsystems are Cc'd only to patches affecting them, and
> >> this cover letter.
> >>
> >> Series also available in git, based on 5.16-rc3:
> >> https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2
> > 
> > Pushed a new branch slab-struct-slab-v3r3 with accumulated fixes and small tweaks
> > and a new patch from Hyeonggon Yoo on top. To avoid too much spam, here's a range diff:
> 
> Hi, I've pushed another update branch slab-struct_slab-v4r1, and also to
> -next. I've shortened git commit log lines to make checkpatch happier,
> so no range-diff as it would be too long. I believe it would be useless
> spam to post the whole series now, shortly before xmas, so I will do it
> at rc8 time, to hopefully collect remaining reviews. But if anyone wants
> a mailed version, I can do that.
>

Hello Matthew and Vlastimil.
it's part 3 of review.

# mm: Convert struct page to struct slab in functions used by other subsystems
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>


# mm/slub: Convert most struct page to struct slab by spatch
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
with a question below.

-static int check_slab(struct kmem_cache *s, struct page *page)
+static int check_slab(struct kmem_cache *s, struct slab *slab)
 {
        int maxobj;
 
-       if (!PageSlab(page)) {
-               slab_err(s, page, "Not a valid slab page");
+       if (!folio_test_slab(slab_folio(slab))) {
+               slab_err(s, slab, "Not a valid slab page");
                return 0;
        }

Can't we guarantee that struct slab * always points to a slab?

for struct page * it can be !PageSlab(page) because struct page *
can be other than slab. but struct slab * can only be slab
unlike struct page. code will be simpler if we guarantee that
struct slab * always points to a slab (or NULL).


# mm/slub: Convert pfmemalloc_match() to take a struct slab
It's confusing to me because the original pfmemalloc_match() is removed
and pfmemalloc_match_unsafe() was renamed to pfmemalloc_match() and
converted to use slab_test_pfmemalloc() helper.

But I agree with the resulting code. so:
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>


# mm/slub: Convert alloc_slab_page() to return a struct slab
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>


# mm/slub: Convert print_page_info() to print_slab_info()
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

I hope to review rest of patches in a week.

Thanks,
Hyeonggon

> Changes in v4:
> - rebase to 5.16-rc6 to avoid a conflict with mainline
> - collect acks/reviews/tested-by from Johannes, Roman, Hyeonggon Yoo -
> thanks!
> - in patch "mm/slub: Convert detached_freelist to use a struct slab"
> renamed free_nonslab_page() to free_large_kmalloc() and use folio there,
> as suggested by Roman
> - in "mm/memcg: Convert slab objcgs from struct page to struct slab"
> change one caller of slab_objcgs_check() to slab_objcgs() as suggested
> by Johannes, realize the other caller should be also changed, and remove
> slab_objcgs_check() completely.

Re: [PATCH v2 00/33] Separate struct slab from struct page

[Vlastimil Babka]

On 12/29/21 12:22, Hyeonggon Yoo wrote:
> On Wed, Dec 22, 2021 at 05:56:50PM +0100, Vlastimil Babka wrote:
>> On 12/14/21 13:57, Vlastimil Babka wrote:
>> > On 12/1/21 19:14, Vlastimil Babka wrote:
>> >> Folks from non-slab subsystems are Cc'd only to patches affecting them, and
>> >> this cover letter.
>> >>
>> >> Series also available in git, based on 5.16-rc3:
>> >> https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slab-struct_slab-v2r2
>> > 
>> > Pushed a new branch slab-struct-slab-v3r3 with accumulated fixes and small tweaks
>> > and a new patch from Hyeonggon Yoo on top. To avoid too much spam, here's a range diff:
>> 
>> Hi, I've pushed another update branch slab-struct_slab-v4r1, and also to
>> -next. I've shortened git commit log lines to make checkpatch happier,
>> so no range-diff as it would be too long. I believe it would be useless
>> spam to post the whole series now, shortly before xmas, so I will do it
>> at rc8 time, to hopefully collect remaining reviews. But if anyone wants
>> a mailed version, I can do that.
>>
> 
> Hello Matthew and Vlastimil.
> it's part 3 of review.
> 
> # mm: Convert struct page to struct slab in functions used by other subsystems
> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> 
> 
> # mm/slub: Convert most struct page to struct slab by spatch
> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> with a question below.
> 
> -static int check_slab(struct kmem_cache *s, struct page *page)
> +static int check_slab(struct kmem_cache *s, struct slab *slab)
>  {
>         int maxobj;
>  
> -       if (!PageSlab(page)) {
> -               slab_err(s, page, "Not a valid slab page");
> +       if (!folio_test_slab(slab_folio(slab))) {
> +               slab_err(s, slab, "Not a valid slab page");
>                 return 0;
>         }
> 
> Can't we guarantee that struct slab * always points to a slab?

Normally, yes.

> for struct page * it can be !PageSlab(page) because struct page *
> can be other than slab. but struct slab * can only be slab
> unlike struct page. code will be simpler if we guarantee that
> struct slab * always points to a slab (or NULL).

That's what the code does indeed. But check_slab() is called as part of
various consistency checks, so there we on purpose question all assumptions
in order to find a bug (e.g. memory corruption) - such as a page that's
still on the list of slabs while it was already freed and reused and thus
e.g. lacks the slab page flag.

But it's nice how using struct slab makes such a check immediately stand out
as suspicious, right?

> # mm/slub: Convert pfmemalloc_match() to take a struct slab
> It's confusing to me because the original pfmemalloc_match() is removed
> and pfmemalloc_match_unsafe() was renamed to pfmemalloc_match() and
> converted to use slab_test_pfmemalloc() helper.
> 
> But I agree with the resulting code. so:
> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> 
> 
> # mm/slub: Convert alloc_slab_page() to return a struct slab
> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> 
> 
> # mm/slub: Convert print_page_info() to print_slab_info()
> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> 
> I hope to review rest of patches in a week.

Thanks for your reviews/tests!