[PATCH v6 00/33] Split ptdesc from struct page

[PATCH v6 00/33] Split ptdesc from struct page

[Vishal Moola (Oracle)]

The MM subsystem is trying to shrink struct page. This patchset
introduces a memory descriptor for page table tracking - struct ptdesc.

This patchset introduces ptdesc, splits ptdesc from struct page, and
converts many callers of page table constructor/destructors to use ptdescs.

Ptdesc is a foundation to further standardize page tables, and eventually
allow for dynamic allocation of page tables independent of struct page.
However, the use of pages for page table tracking is quite deeply
ingrained and varied across archictectures, so there is still a lot of
work to be done before that can happen.

This is rebased on next-20230626.

There is a minor conflict with patch 24 and the mm-unstable tree in
arch/m68k/mm/motorola.c - The end result of applying the patch should
be the same.

v6:
  Fix compiler warnings/errors

v5:
  More Acked-bys :)
  Cleanup some documentation wording and formatting
  Add pt_rcu_head to ptdesc
  Add memcg to ptdesc (and align it with struct page)
  Ensure all get_free_page() callers prohibit HIGHMEM for 32 bit support.
  Renamed folio_{set, clear}_table() to folio_{set, clear}_pgtable()
  Removed pagetable_clear() as it is not necessary right now
  Dropped s390 _refcount to _pt_frag_refcount conversion

Vishal Moola (Oracle) (33):
  mm: Add PAGE_TYPE_OP folio functions
  s390: Use _pt_s390_gaddr for gmap address tracking
  pgtable: Create struct ptdesc
  mm: add utility functions for ptdesc
  mm: Convert pmd_pgtable_page() to pmd_ptdesc()
  mm: Convert ptlock_alloc() to use ptdescs
  mm: Convert ptlock_ptr() to use ptdescs
  mm: Convert pmd_ptlock_init() to use ptdescs
  mm: Convert ptlock_init() to use ptdescs
  mm: Convert pmd_ptlock_free() to use ptdescs
  mm: Convert ptlock_free() to use ptdescs
  mm: Create ptdesc equivalents for pgtable_{pte,pmd}_page_{ctor,dtor}
  powerpc: Convert various functions to use ptdescs
  x86: Convert various functions to use ptdescs
  s390: Convert various gmap functions to use ptdescs
  s390: Convert various pgalloc functions to use ptdescs
  mm: Remove page table members from struct page
  pgalloc: Convert various functions to use ptdescs
  arm: Convert various functions to use ptdescs
  arm64: Convert various functions to use ptdescs
  csky: Convert __pte_free_tlb() to use ptdescs
  hexagon: Convert __pte_free_tlb() to use ptdescs
  loongarch: Convert various functions to use ptdescs
  m68k: Convert various functions to use ptdescs
  mips: Convert various functions to use ptdescs
  nios2: Convert __pte_free_tlb() to use ptdescs
  openrisc: Convert __pte_free_tlb() to use ptdescs
  riscv: Convert alloc_{pmd, pte}_late() to use ptdescs
  sh: Convert pte_free_tlb() to use ptdescs
  sparc64: Convert various functions to use ptdescs
  sparc: Convert pgtable_pte_page_{ctor, dtor}() to ptdesc equivalents
  um: Convert {pmd, pte}_free_tlb() to use ptdescs
  mm: Remove pgtable_{pmd, pte}_page_{ctor, dtor}() wrappers

 Documentation/mm/split_page_table_lock.rst    |  12 +-
 .../zh_CN/mm/split_page_table_lock.rst        |  14 +-
 arch/arm/include/asm/tlb.h                    |  12 +-
 arch/arm/mm/mmu.c                             |   7 +-
 arch/arm64/include/asm/tlb.h                  |  14 +-
 arch/arm64/mm/mmu.c                           |   7 +-
 arch/csky/include/asm/pgalloc.h               |   4 +-
 arch/hexagon/include/asm/pgalloc.h            |   8 +-
 arch/loongarch/include/asm/pgalloc.h          |  27 ++-
 arch/loongarch/mm/pgtable.c                   |   7 +-
 arch/m68k/include/asm/mcf_pgalloc.h           |  47 ++--
 arch/m68k/include/asm/sun3_pgalloc.h          |   8 +-
 arch/m68k/mm/motorola.c                       |   4 +-
 arch/mips/include/asm/pgalloc.h               |  32 +--
 arch/mips/mm/pgtable.c                        |   8 +-
 arch/nios2/include/asm/pgalloc.h              |   8 +-
 arch/openrisc/include/asm/pgalloc.h           |   8 +-
 arch/powerpc/mm/book3s64/mmu_context.c        |  10 +-
 arch/powerpc/mm/book3s64/pgtable.c            |  32 +--
 arch/powerpc/mm/pgtable-frag.c                |  46 ++--
 arch/riscv/include/asm/pgalloc.h              |   8 +-
 arch/riscv/mm/init.c                          |  16 +-
 arch/s390/include/asm/pgalloc.h               |   4 +-
 arch/s390/include/asm/tlb.h                   |   4 +-
 arch/s390/mm/gmap.c                           | 207 ++++++++++--------
 arch/s390/mm/pgalloc.c                        | 108 ++++-----
 arch/sh/include/asm/pgalloc.h                 |   9 +-
 arch/sparc/mm/init_64.c                       |  17 +-
 arch/sparc/mm/srmmu.c                         |   5 +-
 arch/um/include/asm/pgalloc.h                 |  18 +-
 arch/x86/mm/pgtable.c                         |  47 ++--
 arch/x86/xen/mmu_pv.c                         |   2 +-
 include/asm-generic/pgalloc.h                 |  88 +++++---
 include/asm-generic/tlb.h                     |  11 +
 include/linux/mm.h                            | 153 +++++++++----
 include/linux/mm_types.h                      |  14 --
 include/linux/page-flags.h                    |  30 ++-
 include/linux/pgtable.h                       |  77 +++++++
 mm/memory.c                                   |   8 +-
 39 files changed, 686 insertions(+), 455 deletions(-)

-- 
2.40.1

[PATCH v6 01/33] mm: Add PAGE_TYPE_OP folio functions

[Vishal Moola (Oracle)]

No folio equivalents for page type operations have been defined, so
define them for later folio conversions.

Also changes the Page##uname macros to take in const struct page* since
we only read the memory here.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 include/linux/page-flags.h | 30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 92a2063a0a23..9218028caf33 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -908,6 +908,8 @@ static inline bool is_page_hwpoison(struct page *page)
 
 #define PageType(page, flag)						\
 	((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
+#define folio_test_type(folio, flag)					\
+	((folio->page.page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
 
 static inline int page_type_has_type(unsigned int page_type)
 {
@@ -919,27 +921,41 @@ static inline int page_has_type(struct page *page)
 	return page_type_has_type(page->page_type);
 }
 
-#define PAGE_TYPE_OPS(uname, lname)					\
-static __always_inline int Page##uname(struct page *page)		\
+#define PAGE_TYPE_OPS(uname, lname, fname)				\
+static __always_inline int Page##uname(const struct page *page)		\
 {									\
 	return PageType(page, PG_##lname);				\
 }									\
+static __always_inline int folio_test_##fname(const struct folio *folio)\
+{									\
+	return folio_test_type(folio, PG_##lname);			\
+}									\
 static __always_inline void __SetPage##uname(struct page *page)		\
 {									\
 	VM_BUG_ON_PAGE(!PageType(page, 0), page);			\
 	page->page_type &= ~PG_##lname;					\
 }									\
+static __always_inline void __folio_set_##fname(struct folio *folio)	\
+{									\
+	VM_BUG_ON_FOLIO(!folio_test_type(folio, 0), folio);		\
+	folio->page.page_type &= ~PG_##lname;				\
+}									\
 static __always_inline void __ClearPage##uname(struct page *page)	\
 {									\
 	VM_BUG_ON_PAGE(!Page##uname(page), page);			\
 	page->page_type |= PG_##lname;					\
-}
+}									\
+static __always_inline void __folio_clear_##fname(struct folio *folio)	\
+{									\
+	VM_BUG_ON_FOLIO(!folio_test_##fname(folio), folio);		\
+	folio->page.page_type |= PG_##lname;				\
+}									\
 
 /*
  * PageBuddy() indicates that the page is free and in the buddy system
  * (see mm/page_alloc.c).
  */
-PAGE_TYPE_OPS(Buddy, buddy)
+PAGE_TYPE_OPS(Buddy, buddy, buddy)
 
 /*
  * PageOffline() indicates that the page is logically offline although the
@@ -963,7 +979,7 @@ PAGE_TYPE_OPS(Buddy, buddy)
  * pages should check PageOffline() and synchronize with such drivers using
  * page_offline_freeze()/page_offline_thaw().
  */
-PAGE_TYPE_OPS(Offline, offline)
+PAGE_TYPE_OPS(Offline, offline, offline)
 
 extern void page_offline_freeze(void);
 extern void page_offline_thaw(void);
@@ -973,12 +989,12 @@ extern void page_offline_end(void);
 /*
  * Marks pages in use as page tables.
  */
-PAGE_TYPE_OPS(Table, table)
+PAGE_TYPE_OPS(Table, table, pgtable)
 
 /*
  * Marks guardpages used with debug_pagealloc.
  */
-PAGE_TYPE_OPS(Guard, guard)
+PAGE_TYPE_OPS(Guard, guard, guard)
 
 extern bool is_free_buddy_page(struct page *page);
 
-- 
2.40.1

[PATCH v6 02/33] s390: Use _pt_s390_gaddr for gmap address tracking

[Vishal Moola (Oracle)]

s390 uses page->index to keep track of page tables for the guest address
space. In an attempt to consolidate the usage of page fields in s390,
replace _pt_pad_2 with _pt_s390_gaddr to replace page->index in gmap.

Since page->_pt_s390_gaddr aliases with mapping, ensure its set to NULL
before freeing the pages as well.

This also reverts commit 7e25de77bc5ea ("s390/mm: use pmd_pgtable_page()
helper in __gmap_segment_gaddr()") which had s390 use
pmd_pgtable_page() to get a gmap page table, as pmd_pgtable_page()
should be used for more generic process page tables.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/s390/mm/gmap.c      | 56 +++++++++++++++++++++++++++-------------
 include/linux/mm_types.h |  2 +-
 2 files changed, 39 insertions(+), 19 deletions(-)

diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index f4b6fc746fce..beb4804d9ca8 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -70,7 +70,7 @@ static struct gmap *gmap_alloc(unsigned long limit)
 	page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
 	if (!page)
 		goto out_free;
-	page->index = 0;
+	page->_pt_s390_gaddr = 0;
 	list_add(&page->lru, &gmap->crst_list);
 	table = page_to_virt(page);
 	crst_table_init(table, etype);
@@ -187,16 +187,20 @@ static void gmap_free(struct gmap *gmap)
 	if (!(gmap_is_shadow(gmap) && gmap->removed))
 		gmap_flush_tlb(gmap);
 	/* Free all segment & region tables. */
-	list_for_each_entry_safe(page, next, &gmap->crst_list, lru)
+	list_for_each_entry_safe(page, next, &gmap->crst_list, lru) {
+		page->_pt_s390_gaddr = 0;
 		__free_pages(page, CRST_ALLOC_ORDER);
+	}
 	gmap_radix_tree_free(&gmap->guest_to_host);
 	gmap_radix_tree_free(&gmap->host_to_guest);
 
 	/* Free additional data for a shadow gmap */
 	if (gmap_is_shadow(gmap)) {
 		/* Free all page tables. */
-		list_for_each_entry_safe(page, next, &gmap->pt_list, lru)
+		list_for_each_entry_safe(page, next, &gmap->pt_list, lru) {
+			page->_pt_s390_gaddr = 0;
 			page_table_free_pgste(page);
+		}
 		gmap_rmap_radix_tree_free(&gmap->host_to_rmap);
 		/* Release reference to the parent */
 		gmap_put(gmap->parent);
@@ -318,12 +322,14 @@ static int gmap_alloc_table(struct gmap *gmap, unsigned long *table,
 		list_add(&page->lru, &gmap->crst_list);
 		*table = __pa(new) | _REGION_ENTRY_LENGTH |
 			(*table & _REGION_ENTRY_TYPE_MASK);
-		page->index = gaddr;
+		page->_pt_s390_gaddr = gaddr;
 		page = NULL;
 	}
 	spin_unlock(&gmap->guest_table_lock);
-	if (page)
+	if (page) {
+		page->_pt_s390_gaddr = 0;
 		__free_pages(page, CRST_ALLOC_ORDER);
+	}
 	return 0;
 }
 
@@ -336,12 +342,14 @@ static int gmap_alloc_table(struct gmap *gmap, unsigned long *table,
 static unsigned long __gmap_segment_gaddr(unsigned long *entry)
 {
 	struct page *page;
-	unsigned long offset;
+	unsigned long offset, mask;
 
 	offset = (unsigned long) entry / sizeof(unsigned long);
 	offset = (offset & (PTRS_PER_PMD - 1)) * PMD_SIZE;
-	page = pmd_pgtable_page((pmd_t *) entry);
-	return page->index + offset;
+	mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
+	page = virt_to_page((void *)((unsigned long) entry & mask));
+
+	return page->_pt_s390_gaddr + offset;
 }
 
 /**
@@ -1351,6 +1359,7 @@ static void gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr)
 	/* Free page table */
 	page = phys_to_page(pgt);
 	list_del(&page->lru);
+	page->_pt_s390_gaddr = 0;
 	page_table_free_pgste(page);
 }
 
@@ -1379,6 +1388,7 @@ static void __gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr,
 		/* Free page table */
 		page = phys_to_page(pgt);
 		list_del(&page->lru);
+		page->_pt_s390_gaddr = 0;
 		page_table_free_pgste(page);
 	}
 }
@@ -1409,6 +1419,7 @@ static void gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr)
 	/* Free segment table */
 	page = phys_to_page(sgt);
 	list_del(&page->lru);
+	page->_pt_s390_gaddr = 0;
 	__free_pages(page, CRST_ALLOC_ORDER);
 }
 
@@ -1437,6 +1448,7 @@ static void __gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr,
 		/* Free segment table */
 		page = phys_to_page(sgt);
 		list_del(&page->lru);
+		page->_pt_s390_gaddr = 0;
 		__free_pages(page, CRST_ALLOC_ORDER);
 	}
 }
@@ -1467,6 +1479,7 @@ static void gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr)
 	/* Free region 3 table */
 	page = phys_to_page(r3t);
 	list_del(&page->lru);
+	page->_pt_s390_gaddr = 0;
 	__free_pages(page, CRST_ALLOC_ORDER);
 }
 
@@ -1495,6 +1508,7 @@ static void __gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr,
 		/* Free region 3 table */
 		page = phys_to_page(r3t);
 		list_del(&page->lru);
+		page->_pt_s390_gaddr = 0;
 		__free_pages(page, CRST_ALLOC_ORDER);
 	}
 }
@@ -1525,6 +1539,7 @@ static void gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr)
 	/* Free region 2 table */
 	page = phys_to_page(r2t);
 	list_del(&page->lru);
+	page->_pt_s390_gaddr = 0;
 	__free_pages(page, CRST_ALLOC_ORDER);
 }
 
@@ -1557,6 +1572,7 @@ static void __gmap_unshadow_r1t(struct gmap *sg, unsigned long raddr,
 		/* Free region 2 table */
 		page = phys_to_page(r2t);
 		list_del(&page->lru);
+		page->_pt_s390_gaddr = 0;
 		__free_pages(page, CRST_ALLOC_ORDER);
 	}
 }
@@ -1762,9 +1778,9 @@ int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t,
 	page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
 	if (!page)
 		return -ENOMEM;
-	page->index = r2t & _REGION_ENTRY_ORIGIN;
+	page->_pt_s390_gaddr = r2t & _REGION_ENTRY_ORIGIN;
 	if (fake)
-		page->index |= GMAP_SHADOW_FAKE_TABLE;
+		page->_pt_s390_gaddr |= GMAP_SHADOW_FAKE_TABLE;
 	s_r2t = page_to_phys(page);
 	/* Install shadow region second table */
 	spin_lock(&sg->guest_table_lock);
@@ -1814,6 +1830,7 @@ int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t,
 	return rc;
 out_free:
 	spin_unlock(&sg->guest_table_lock);
+	page->_pt_s390_gaddr = 0;
 	__free_pages(page, CRST_ALLOC_ORDER);
 	return rc;
 }
@@ -1846,9 +1863,9 @@ int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t,
 	page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
 	if (!page)
 		return -ENOMEM;
-	page->index = r3t & _REGION_ENTRY_ORIGIN;
+	page->_pt_s390_gaddr = r3t & _REGION_ENTRY_ORIGIN;
 	if (fake)
-		page->index |= GMAP_SHADOW_FAKE_TABLE;
+		page->_pt_s390_gaddr |= GMAP_SHADOW_FAKE_TABLE;
 	s_r3t = page_to_phys(page);
 	/* Install shadow region second table */
 	spin_lock(&sg->guest_table_lock);
@@ -1898,6 +1915,7 @@ int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t,
 	return rc;
 out_free:
 	spin_unlock(&sg->guest_table_lock);
+	page->_pt_s390_gaddr = 0;
 	__free_pages(page, CRST_ALLOC_ORDER);
 	return rc;
 }
@@ -1930,9 +1948,9 @@ int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt,
 	page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
 	if (!page)
 		return -ENOMEM;
-	page->index = sgt & _REGION_ENTRY_ORIGIN;
+	page->_pt_s390_gaddr = sgt & _REGION_ENTRY_ORIGIN;
 	if (fake)
-		page->index |= GMAP_SHADOW_FAKE_TABLE;
+		page->_pt_s390_gaddr |= GMAP_SHADOW_FAKE_TABLE;
 	s_sgt = page_to_phys(page);
 	/* Install shadow region second table */
 	spin_lock(&sg->guest_table_lock);
@@ -1982,6 +2000,7 @@ int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt,
 	return rc;
 out_free:
 	spin_unlock(&sg->guest_table_lock);
+	page->_pt_s390_gaddr = 0;
 	__free_pages(page, CRST_ALLOC_ORDER);
 	return rc;
 }
@@ -2014,9 +2033,9 @@ int gmap_shadow_pgt_lookup(struct gmap *sg, unsigned long saddr,
 	if (table && !(*table & _SEGMENT_ENTRY_INVALID)) {
 		/* Shadow page tables are full pages (pte+pgste) */
 		page = pfn_to_page(*table >> PAGE_SHIFT);
-		*pgt = page->index & ~GMAP_SHADOW_FAKE_TABLE;
+		*pgt = page->_pt_s390_gaddr & ~GMAP_SHADOW_FAKE_TABLE;
 		*dat_protection = !!(*table & _SEGMENT_ENTRY_PROTECT);
-		*fake = !!(page->index & GMAP_SHADOW_FAKE_TABLE);
+		*fake = !!(page->_pt_s390_gaddr & GMAP_SHADOW_FAKE_TABLE);
 		rc = 0;
 	} else  {
 		rc = -EAGAIN;
@@ -2054,9 +2073,9 @@ int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt,
 	page = page_table_alloc_pgste(sg->mm);
 	if (!page)
 		return -ENOMEM;
-	page->index = pgt & _SEGMENT_ENTRY_ORIGIN;
+	page->_pt_s390_gaddr = pgt & _SEGMENT_ENTRY_ORIGIN;
 	if (fake)
-		page->index |= GMAP_SHADOW_FAKE_TABLE;
+		page->_pt_s390_gaddr |= GMAP_SHADOW_FAKE_TABLE;
 	s_pgt = page_to_phys(page);
 	/* Install shadow page table */
 	spin_lock(&sg->guest_table_lock);
@@ -2101,6 +2120,7 @@ int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt,
 	return rc;
 out_free:
 	spin_unlock(&sg->guest_table_lock);
+	page->_pt_s390_gaddr = 0;
 	page_table_free_pgste(page);
 	return rc;
 
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index de10fc797c8e..fbbe4e93a9ba 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -144,7 +144,7 @@ struct page {
 		struct {	/* Page table pages */
 			unsigned long _pt_pad_1;	/* compound_head */
 			pgtable_t pmd_huge_pte; /* protected by page->ptl */
-			unsigned long _pt_pad_2;	/* mapping */
+			unsigned long _pt_s390_gaddr;	/* mapping */
 			union {
 				struct mm_struct *pt_mm; /* x86 pgds only */
 				atomic_t pt_frag_refcount; /* powerpc */
-- 
2.40.1

[PATCH v6 03/33] pgtable: Create struct ptdesc

[Vishal Moola (Oracle)]

Currently, page table information is stored within struct page. As part
of simplifying struct page, create struct ptdesc for page table
information.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 include/linux/pgtable.h | 68 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 5063b482e34f..d46cb709ce08 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -987,6 +987,74 @@ static inline void ptep_modify_prot_commit(struct vm_area_struct *vma,
 #endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
 #endif /* CONFIG_MMU */
 
+
+/**
+ * struct ptdesc -    Memory descriptor for page tables.
+ * @__page_flags:     Same as page flags. Unused for page tables.
+ * @pt_rcu_head:      For freeing page table pages.
+ * @pt_list:          List of used page tables. Used for s390 and x86.
+ * @_pt_pad_1:        Padding that aliases with page's compound head.
+ * @pmd_huge_pte:     Protected by ptdesc->ptl, used for THPs.
+ * @_pt_s390_gaddr:   Aliases with page's mapping. Used for s390 gmap only.
+ * @pt_mm:            Used for x86 pgds.
+ * @pt_frag_refcount: For fragmented page table tracking. Powerpc and s390 only.
+ * @ptl:              Lock for the page table.
+ * @__page_type:      Same as page->page_type. Unused for page tables.
+ * @_refcount:        Same as page refcount. Used for s390 page tables.
+ * @pt_memcg_data:    Memcg data. Tracked for page tables here.
+ *
+ * This struct overlays struct page for now. Do not modify without a good
+ * understanding of the issues.
+ */
+struct ptdesc {
+	unsigned long __page_flags;
+
+	union {
+		struct rcu_head pt_rcu_head;
+		struct list_head pt_list;
+		struct {
+			unsigned long _pt_pad_1;
+			pgtable_t pmd_huge_pte;
+		};
+	};
+	unsigned long _pt_s390_gaddr;
+
+	union {
+		struct mm_struct *pt_mm;
+		atomic_t pt_frag_refcount;
+	};
+
+	union {
+		unsigned long _pt_pad_2;
+#if ALLOC_SPLIT_PTLOCKS
+		spinlock_t *ptl;
+#else
+		spinlock_t ptl;
+#endif
+	};
+	unsigned int __page_type;
+	atomic_t _refcount;
+#ifdef CONFIG_MEMCG
+	unsigned long pt_memcg_data;
+#endif
+};
+
+#define TABLE_MATCH(pg, pt)						\
+	static_assert(offsetof(struct page, pg) == offsetof(struct ptdesc, pt))
+TABLE_MATCH(flags, __page_flags);
+TABLE_MATCH(compound_head, pt_list);
+TABLE_MATCH(compound_head, _pt_pad_1);
+TABLE_MATCH(pmd_huge_pte, pmd_huge_pte);
+TABLE_MATCH(mapping, _pt_s390_gaddr);
+TABLE_MATCH(pt_mm, pt_mm);
+TABLE_MATCH(ptl, ptl);
+TABLE_MATCH(rcu_head, pt_rcu_head);
+#ifdef CONFIG_MEMCG
+TABLE_MATCH(memcg_data, pt_memcg_data);
+#endif
+#undef TABLE_MATCH
+static_assert(sizeof(struct ptdesc) <= sizeof(struct page));
+
 /*
  * No-op macros that just return the current protection value. Defined here
  * because these macros can be used even if CONFIG_MMU is not defined.
-- 
2.40.1

[PATCH v6 04/33] mm: add utility functions for ptdesc

[Vishal Moola (Oracle)]

Introduce utility functions setting the foundation for ptdescs. These
will also assist in the splitting out of ptdesc from struct page.

Functions that focus on the descriptor are prefixed with ptdesc_* while
functions that focus on the pagetable are prefixed with pagetable_*.

pagetable_alloc() is defined to allocate new ptdesc pages as compound
pages. This is to standardize ptdescs by allowing for one allocation
and one free function, in contrast to 2 allocation and 2 free functions.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
---
 include/asm-generic/tlb.h | 11 ++++++++
 include/linux/mm.h        | 56 +++++++++++++++++++++++++++++++++++++++
 include/linux/pgtable.h   | 12 +++++++++
 3 files changed, 79 insertions(+)

diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index b46617207c93..6bade9e0e799 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -481,6 +481,17 @@ static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
 	return tlb_remove_page_size(tlb, page, PAGE_SIZE);
 }
 
+static inline void tlb_remove_ptdesc(struct mmu_gather *tlb, void *pt)
+{
+	tlb_remove_table(tlb, pt);
+}
+
+/* Like tlb_remove_ptdesc, but for page-like page directories. */
+static inline void tlb_remove_page_ptdesc(struct mmu_gather *tlb, struct ptdesc *pt)
+{
+	tlb_remove_page(tlb, ptdesc_page(pt));
+}
+
 static inline void tlb_change_page_size(struct mmu_gather *tlb,
 						     unsigned int page_size)
 {
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0dad5f40ef96..14d95d494958 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2744,6 +2744,57 @@ static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long a
 }
 #endif /* CONFIG_MMU */
 
+static inline struct ptdesc *virt_to_ptdesc(const void *x)
+{
+	return page_ptdesc(virt_to_page(x));
+}
+
+static inline void *ptdesc_to_virt(const struct ptdesc *pt)
+{
+	return page_to_virt(ptdesc_page(pt));
+}
+
+static inline void *ptdesc_address(const struct ptdesc *pt)
+{
+	return folio_address(ptdesc_folio(pt));
+}
+
+static inline bool pagetable_is_reserved(struct ptdesc *pt)
+{
+	return folio_test_reserved(ptdesc_folio(pt));
+}
+
+/**
+ * pagetable_alloc - Allocate pagetables
+ * @gfp:    GFP flags
+ * @order:  desired pagetable order
+ *
+ * pagetable_alloc allocates memory for page tables as well as a page table
+ * descriptor to describe that memory.
+ *
+ * Return: The ptdesc describing the allocated page tables.
+ */
+static inline struct ptdesc *pagetable_alloc(gfp_t gfp, unsigned int order)
+{
+	struct page *page = alloc_pages(gfp | __GFP_COMP, order);
+
+	return page_ptdesc(page);
+}
+
+/**
+ * pagetable_free - Free pagetables
+ * @pt:	The page table descriptor
+ *
+ * pagetable_free frees the memory of all page tables described by a page
+ * table descriptor and the memory for the descriptor itself.
+ */
+static inline void pagetable_free(struct ptdesc *pt)
+{
+	struct page *page = ptdesc_page(pt);
+
+	__free_pages(page, compound_order(page));
+}
+
 #if USE_SPLIT_PTE_PTLOCKS
 #if ALLOC_SPLIT_PTLOCKS
 void __init ptlock_cache_init(void);
@@ -2981,6 +3032,11 @@ static inline void mark_page_reserved(struct page *page)
 	adjust_managed_page_count(page, -1);
 }
 
+static inline void free_reserved_ptdesc(struct ptdesc *pt)
+{
+	free_reserved_page(ptdesc_page(pt));
+}
+
 /*
  * Default method to free all the __init memory into the buddy system.
  * The freed pages will be poisoned with pattern "poison" if it's within
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index d46cb709ce08..e9bb5f18cade 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1055,6 +1055,18 @@ TABLE_MATCH(memcg_data, pt_memcg_data);
 #undef TABLE_MATCH
 static_assert(sizeof(struct ptdesc) <= sizeof(struct page));
 
+#define ptdesc_page(pt)			(_Generic((pt),			\
+	const struct ptdesc *:		(const struct page *)(pt),	\
+	struct ptdesc *:		(struct page *)(pt)))
+
+#define ptdesc_folio(pt)		(_Generic((pt),			\
+	const struct ptdesc *:		(const struct folio *)(pt),	\
+	struct ptdesc *:		(struct folio *)(pt)))
+
+#define page_ptdesc(p)			(_Generic((p),			\
+	const struct page *:		(const struct ptdesc *)(p),	\
+	struct page *:			(struct ptdesc *)(p)))
+
 /*
  * No-op macros that just return the current protection value. Defined here
  * because these macros can be used even if CONFIG_MMU is not defined.
-- 
2.40.1

[PATCH v6 05/33] mm: Convert pmd_pgtable_page() to pmd_ptdesc()

[Vishal Moola (Oracle)]

Converts pmd_pgtable_page() to pmd_ptdesc() and all its callers. This
removes some direct accesses to struct page, working towards splitting
out struct ptdesc from struct page.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 include/linux/mm.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 14d95d494958..1511faf0263c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2915,15 +2915,15 @@ pte_t *pte_offset_map_nolock(struct mm_struct *mm, pmd_t *pmd,
 
 #if USE_SPLIT_PMD_PTLOCKS
 
-static inline struct page *pmd_pgtable_page(pmd_t *pmd)
+static inline struct ptdesc *pmd_ptdesc(pmd_t *pmd)
 {
 	unsigned long mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
-	return virt_to_page((void *)((unsigned long) pmd & mask));
+	return virt_to_ptdesc((void *)((unsigned long) pmd & mask));
 }
 
 static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
 {
-	return ptlock_ptr(pmd_pgtable_page(pmd));
+	return ptlock_ptr(ptdesc_page(pmd_ptdesc(pmd)));
 }
 
 static inline bool pmd_ptlock_init(struct page *page)
@@ -2942,7 +2942,7 @@ static inline void pmd_ptlock_free(struct page *page)
 	ptlock_free(page);
 }
 
-#define pmd_huge_pte(mm, pmd) (pmd_pgtable_page(pmd)->pmd_huge_pte)
+#define pmd_huge_pte(mm, pmd) (pmd_ptdesc(pmd)->pmd_huge_pte)
 
 #else
 
-- 
2.40.1

[PATCH v6 06/33] mm: Convert ptlock_alloc() to use ptdescs

[Vishal Moola (Oracle)]

This removes some direct accesses to struct page, working towards
splitting out struct ptdesc from struct page.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 include/linux/mm.h | 6 +++---
 mm/memory.c        | 4 ++--
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1511faf0263c..39b0a4661e44 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2798,7 +2798,7 @@ static inline void pagetable_free(struct ptdesc *pt)
 #if USE_SPLIT_PTE_PTLOCKS
 #if ALLOC_SPLIT_PTLOCKS
 void __init ptlock_cache_init(void);
-extern bool ptlock_alloc(struct page *page);
+bool ptlock_alloc(struct ptdesc *ptdesc);
 extern void ptlock_free(struct page *page);
 
 static inline spinlock_t *ptlock_ptr(struct page *page)
@@ -2810,7 +2810,7 @@ static inline void ptlock_cache_init(void)
 {
 }
 
-static inline bool ptlock_alloc(struct page *page)
+static inline bool ptlock_alloc(struct ptdesc *ptdesc)
 {
 	return true;
 }
@@ -2840,7 +2840,7 @@ static inline bool ptlock_init(struct page *page)
 	 * slab code uses page->slab_cache, which share storage with page->ptl.
 	 */
 	VM_BUG_ON_PAGE(*(unsigned long *)&page->ptl, page);
-	if (!ptlock_alloc(page))
+	if (!ptlock_alloc(page_ptdesc(page)))
 		return false;
 	spin_lock_init(ptlock_ptr(page));
 	return true;
diff --git a/mm/memory.c b/mm/memory.c
index 80faf3e76232..2ff14f50c7b3 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5920,14 +5920,14 @@ void __init ptlock_cache_init(void)
 			SLAB_PANIC, NULL);
 }
 
-bool ptlock_alloc(struct page *page)
+bool ptlock_alloc(struct ptdesc *ptdesc)
 {
 	spinlock_t *ptl;
 
 	ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL);
 	if (!ptl)
 		return false;
-	page->ptl = ptl;
+	ptdesc->ptl = ptl;
 	return true;
 }
 
-- 
2.40.1

[PATCH v6 07/33] mm: Convert ptlock_ptr() to use ptdescs

[Vishal Moola (Oracle)]

This removes some direct accesses to struct page, working towards
splitting out struct ptdesc from struct page.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/x86/xen/mmu_pv.c |  2 +-
 include/linux/mm.h    | 14 +++++++-------
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index e0a975165de7..8796ec310483 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -667,7 +667,7 @@ static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
 	spinlock_t *ptl = NULL;
 
 #if USE_SPLIT_PTE_PTLOCKS
-	ptl = ptlock_ptr(page);
+	ptl = ptlock_ptr(page_ptdesc(page));
 	spin_lock_nest_lock(ptl, &mm->page_table_lock);
 #endif
 
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 39b0a4661e44..0b230d5d229a 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2801,9 +2801,9 @@ void __init ptlock_cache_init(void);
 bool ptlock_alloc(struct ptdesc *ptdesc);
 extern void ptlock_free(struct page *page);
 
-static inline spinlock_t *ptlock_ptr(struct page *page)
+static inline spinlock_t *ptlock_ptr(struct ptdesc *ptdesc)
 {
-	return page->ptl;
+	return ptdesc->ptl;
 }
 #else /* ALLOC_SPLIT_PTLOCKS */
 static inline void ptlock_cache_init(void)
@@ -2819,15 +2819,15 @@ static inline void ptlock_free(struct page *page)
 {
 }
 
-static inline spinlock_t *ptlock_ptr(struct page *page)
+static inline spinlock_t *ptlock_ptr(struct ptdesc *ptdesc)
 {
-	return &page->ptl;
+	return &ptdesc->ptl;
 }
 #endif /* ALLOC_SPLIT_PTLOCKS */
 
 static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
 {
-	return ptlock_ptr(pmd_page(*pmd));
+	return ptlock_ptr(page_ptdesc(pmd_page(*pmd)));
 }
 
 static inline bool ptlock_init(struct page *page)
@@ -2842,7 +2842,7 @@ static inline bool ptlock_init(struct page *page)
 	VM_BUG_ON_PAGE(*(unsigned long *)&page->ptl, page);
 	if (!ptlock_alloc(page_ptdesc(page)))
 		return false;
-	spin_lock_init(ptlock_ptr(page));
+	spin_lock_init(ptlock_ptr(page_ptdesc(page)));
 	return true;
 }
 
@@ -2923,7 +2923,7 @@ static inline struct ptdesc *pmd_ptdesc(pmd_t *pmd)
 
 static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
 {
-	return ptlock_ptr(ptdesc_page(pmd_ptdesc(pmd)));
+	return ptlock_ptr(pmd_ptdesc(pmd));
 }
 
 static inline bool pmd_ptlock_init(struct page *page)
-- 
2.40.1

[PATCH v6 08/33] mm: Convert pmd_ptlock_init() to use ptdescs

[Vishal Moola (Oracle)]

This removes some direct accesses to struct page, working towards
splitting out struct ptdesc from struct page.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 include/linux/mm.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0b230d5d229a..1c4c6a7b69b3 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2926,12 +2926,12 @@ static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
 	return ptlock_ptr(pmd_ptdesc(pmd));
 }
 
-static inline bool pmd_ptlock_init(struct page *page)
+static inline bool pmd_ptlock_init(struct ptdesc *ptdesc)
 {
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-	page->pmd_huge_pte = NULL;
+	ptdesc->pmd_huge_pte = NULL;
 #endif
-	return ptlock_init(page);
+	return ptlock_init(ptdesc_page(ptdesc));
 }
 
 static inline void pmd_ptlock_free(struct page *page)
@@ -2951,7 +2951,7 @@ static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
 	return &mm->page_table_lock;
 }
 
-static inline bool pmd_ptlock_init(struct page *page) { return true; }
+static inline bool pmd_ptlock_init(struct ptdesc *ptdesc) { return true; }
 static inline void pmd_ptlock_free(struct page *page) {}
 
 #define pmd_huge_pte(mm, pmd) ((mm)->pmd_huge_pte)
@@ -2967,7 +2967,7 @@ static inline spinlock_t *pmd_lock(struct mm_struct *mm, pmd_t *pmd)
 
 static inline bool pgtable_pmd_page_ctor(struct page *page)
 {
-	if (!pmd_ptlock_init(page))
+	if (!pmd_ptlock_init(page_ptdesc(page)))
 		return false;
 	__SetPageTable(page);
 	inc_lruvec_page_state(page, NR_PAGETABLE);
-- 
2.40.1

[PATCH v6 09/33] mm: Convert ptlock_init() to use ptdescs

[Vishal Moola (Oracle)]

This removes some direct accesses to struct page, working towards
splitting out struct ptdesc from struct page.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 include/linux/mm.h | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1c4c6a7b69b3..4af424e4015a 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2830,7 +2830,7 @@ static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
 	return ptlock_ptr(page_ptdesc(pmd_page(*pmd)));
 }
 
-static inline bool ptlock_init(struct page *page)
+static inline bool ptlock_init(struct ptdesc *ptdesc)
 {
 	/*
 	 * prep_new_page() initialize page->private (and therefore page->ptl)
@@ -2839,10 +2839,10 @@ static inline bool ptlock_init(struct page *page)
 	 * It can happen if arch try to use slab for page table allocation:
 	 * slab code uses page->slab_cache, which share storage with page->ptl.
 	 */
-	VM_BUG_ON_PAGE(*(unsigned long *)&page->ptl, page);
-	if (!ptlock_alloc(page_ptdesc(page)))
+	VM_BUG_ON_PAGE(*(unsigned long *)&ptdesc->ptl, ptdesc_page(ptdesc));
+	if (!ptlock_alloc(ptdesc))
 		return false;
-	spin_lock_init(ptlock_ptr(page_ptdesc(page)));
+	spin_lock_init(ptlock_ptr(ptdesc));
 	return true;
 }
 
@@ -2855,13 +2855,13 @@ static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
 	return &mm->page_table_lock;
 }
 static inline void ptlock_cache_init(void) {}
-static inline bool ptlock_init(struct page *page) { return true; }
+static inline bool ptlock_init(struct ptdesc *ptdesc) { return true; }
 static inline void ptlock_free(struct page *page) {}
 #endif /* USE_SPLIT_PTE_PTLOCKS */
 
 static inline bool pgtable_pte_page_ctor(struct page *page)
 {
-	if (!ptlock_init(page))
+	if (!ptlock_init(page_ptdesc(page)))
 		return false;
 	__SetPageTable(page);
 	inc_lruvec_page_state(page, NR_PAGETABLE);
@@ -2931,7 +2931,7 @@ static inline bool pmd_ptlock_init(struct ptdesc *ptdesc)
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 	ptdesc->pmd_huge_pte = NULL;
 #endif
-	return ptlock_init(ptdesc_page(ptdesc));
+	return ptlock_init(ptdesc);
 }
 
 static inline void pmd_ptlock_free(struct page *page)
-- 
2.40.1

[PATCH v6 10/33] mm: Convert pmd_ptlock_free() to use ptdescs

[Vishal Moola (Oracle)]

This removes some direct accesses to struct page, working towards
splitting out struct ptdesc from struct page.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 include/linux/mm.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 4af424e4015a..0221675e4dc5 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2934,12 +2934,12 @@ static inline bool pmd_ptlock_init(struct ptdesc *ptdesc)
 	return ptlock_init(ptdesc);
 }
 
-static inline void pmd_ptlock_free(struct page *page)
+static inline void pmd_ptlock_free(struct ptdesc *ptdesc)
 {
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-	VM_BUG_ON_PAGE(page->pmd_huge_pte, page);
+	VM_BUG_ON_PAGE(ptdesc->pmd_huge_pte, ptdesc_page(ptdesc));
 #endif
-	ptlock_free(page);
+	ptlock_free(ptdesc_page(ptdesc));
 }
 
 #define pmd_huge_pte(mm, pmd) (pmd_ptdesc(pmd)->pmd_huge_pte)
@@ -2952,7 +2952,7 @@ static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
 }
 
 static inline bool pmd_ptlock_init(struct ptdesc *ptdesc) { return true; }
-static inline void pmd_ptlock_free(struct page *page) {}
+static inline void pmd_ptlock_free(struct ptdesc *ptdesc) {}
 
 #define pmd_huge_pte(mm, pmd) ((mm)->pmd_huge_pte)
 
@@ -2976,7 +2976,7 @@ static inline bool pgtable_pmd_page_ctor(struct page *page)
 
 static inline void pgtable_pmd_page_dtor(struct page *page)
 {
-	pmd_ptlock_free(page);
+	pmd_ptlock_free(page_ptdesc(page));
 	__ClearPageTable(page);
 	dec_lruvec_page_state(page, NR_PAGETABLE);
 }
-- 
2.40.1

[PATCH v6 11/33] mm: Convert ptlock_free() to use ptdescs

[Vishal Moola (Oracle)]

This removes some direct accesses to struct page, working towards
splitting out struct ptdesc from struct page.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 include/linux/mm.h | 10 +++++-----
 mm/memory.c        |  4 ++--
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0221675e4dc5..69e6d6696c44 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2799,7 +2799,7 @@ static inline void pagetable_free(struct ptdesc *pt)
 #if ALLOC_SPLIT_PTLOCKS
 void __init ptlock_cache_init(void);
 bool ptlock_alloc(struct ptdesc *ptdesc);
-extern void ptlock_free(struct page *page);
+void ptlock_free(struct ptdesc *ptdesc);
 
 static inline spinlock_t *ptlock_ptr(struct ptdesc *ptdesc)
 {
@@ -2815,7 +2815,7 @@ static inline bool ptlock_alloc(struct ptdesc *ptdesc)
 	return true;
 }
 
-static inline void ptlock_free(struct page *page)
+static inline void ptlock_free(struct ptdesc *ptdesc)
 {
 }
 
@@ -2856,7 +2856,7 @@ static inline spinlock_t *pte_lockptr(struct mm_struct *mm, pmd_t *pmd)
 }
 static inline void ptlock_cache_init(void) {}
 static inline bool ptlock_init(struct ptdesc *ptdesc) { return true; }
-static inline void ptlock_free(struct page *page) {}
+static inline void ptlock_free(struct ptdesc *ptdesc) {}
 #endif /* USE_SPLIT_PTE_PTLOCKS */
 
 static inline bool pgtable_pte_page_ctor(struct page *page)
@@ -2870,7 +2870,7 @@ static inline bool pgtable_pte_page_ctor(struct page *page)
 
 static inline void pgtable_pte_page_dtor(struct page *page)
 {
-	ptlock_free(page);
+	ptlock_free(page_ptdesc(page));
 	__ClearPageTable(page);
 	dec_lruvec_page_state(page, NR_PAGETABLE);
 }
@@ -2939,7 +2939,7 @@ static inline void pmd_ptlock_free(struct ptdesc *ptdesc)
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 	VM_BUG_ON_PAGE(ptdesc->pmd_huge_pte, ptdesc_page(ptdesc));
 #endif
-	ptlock_free(ptdesc_page(ptdesc));
+	ptlock_free(ptdesc);
 }
 
 #define pmd_huge_pte(mm, pmd) (pmd_ptdesc(pmd)->pmd_huge_pte)
diff --git a/mm/memory.c b/mm/memory.c
index 2ff14f50c7b3..8743aef6095b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5931,8 +5931,8 @@ bool ptlock_alloc(struct ptdesc *ptdesc)
 	return true;
 }
 
-void ptlock_free(struct page *page)
+void ptlock_free(struct ptdesc *ptdesc)
 {
-	kmem_cache_free(page_ptl_cachep, page->ptl);
+	kmem_cache_free(page_ptl_cachep, ptdesc->ptl);
 }
 #endif
-- 
2.40.1

[PATCH v6 12/33] mm: Create ptdesc equivalents for pgtable_{pte,pmd}_page_{ctor,dtor}

[Vishal Moola (Oracle)]

Create pagetable_pte_ctor(), pagetable_pmd_ctor(), pagetable_pte_dtor(),
and pagetable_pmd_dtor() and make the original pgtable
constructor/destructors wrappers.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 include/linux/mm.h | 56 ++++++++++++++++++++++++++++++++++------------
 1 file changed, 42 insertions(+), 14 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 69e6d6696c44..356e79984cf9 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2859,20 +2859,34 @@ static inline bool ptlock_init(struct ptdesc *ptdesc) { return true; }
 static inline void ptlock_free(struct ptdesc *ptdesc) {}
 #endif /* USE_SPLIT_PTE_PTLOCKS */
 
-static inline bool pgtable_pte_page_ctor(struct page *page)
+static inline bool pagetable_pte_ctor(struct ptdesc *ptdesc)
 {
-	if (!ptlock_init(page_ptdesc(page)))
+	struct folio *folio = ptdesc_folio(ptdesc);
+
+	if (!ptlock_init(ptdesc))
 		return false;
-	__SetPageTable(page);
-	inc_lruvec_page_state(page, NR_PAGETABLE);
+	__folio_set_pgtable(folio);
+	lruvec_stat_add_folio(folio, NR_PAGETABLE);
 	return true;
 }
 
+static inline bool pgtable_pte_page_ctor(struct page *page)
+{
+	return pagetable_pte_ctor(page_ptdesc(page));
+}
+
+static inline void pagetable_pte_dtor(struct ptdesc *ptdesc)
+{
+	struct folio *folio = ptdesc_folio(ptdesc);
+
+	ptlock_free(ptdesc);
+	__folio_clear_pgtable(folio);
+	lruvec_stat_sub_folio(folio, NR_PAGETABLE);
+}
+
 static inline void pgtable_pte_page_dtor(struct page *page)
 {
-	ptlock_free(page_ptdesc(page));
-	__ClearPageTable(page);
-	dec_lruvec_page_state(page, NR_PAGETABLE);
+	pagetable_pte_dtor(page_ptdesc(page));
 }
 
 pte_t *__pte_offset_map(pmd_t *pmd, unsigned long addr, pmd_t *pmdvalp);
@@ -2965,20 +2979,34 @@ static inline spinlock_t *pmd_lock(struct mm_struct *mm, pmd_t *pmd)
 	return ptl;
 }
 
-static inline bool pgtable_pmd_page_ctor(struct page *page)
+static inline bool pagetable_pmd_ctor(struct ptdesc *ptdesc)
 {
-	if (!pmd_ptlock_init(page_ptdesc(page)))
+	struct folio *folio = ptdesc_folio(ptdesc);
+
+	if (!pmd_ptlock_init(ptdesc))
 		return false;
-	__SetPageTable(page);
-	inc_lruvec_page_state(page, NR_PAGETABLE);
+	__folio_set_pgtable(folio);
+	lruvec_stat_add_folio(folio, NR_PAGETABLE);
 	return true;
 }
 
+static inline bool pgtable_pmd_page_ctor(struct page *page)
+{
+	return pagetable_pmd_ctor(page_ptdesc(page));
+}
+
+static inline void pagetable_pmd_dtor(struct ptdesc *ptdesc)
+{
+	struct folio *folio = ptdesc_folio(ptdesc);
+
+	pmd_ptlock_free(ptdesc);
+	__folio_clear_pgtable(folio);
+	lruvec_stat_sub_folio(folio, NR_PAGETABLE);
+}
+
 static inline void pgtable_pmd_page_dtor(struct page *page)
 {
-	pmd_ptlock_free(page_ptdesc(page));
-	__ClearPageTable(page);
-	dec_lruvec_page_state(page, NR_PAGETABLE);
+	pagetable_pmd_dtor(page_ptdesc(page));
 }
 
 /*
-- 
2.40.1

[PATCH v6 13/33] powerpc: Convert various functions to use ptdescs

[Vishal Moola (Oracle)]

In order to split struct ptdesc from struct page, convert various
functions to use ptdescs.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/powerpc/mm/book3s64/mmu_context.c | 10 +++---
 arch/powerpc/mm/book3s64/pgtable.c     | 32 +++++++++---------
 arch/powerpc/mm/pgtable-frag.c         | 46 +++++++++++++-------------
 3 files changed, 44 insertions(+), 44 deletions(-)

diff --git a/arch/powerpc/mm/book3s64/mmu_context.c b/arch/powerpc/mm/book3s64/mmu_context.c
index c766e4c26e42..1715b07c630c 100644
--- a/arch/powerpc/mm/book3s64/mmu_context.c
+++ b/arch/powerpc/mm/book3s64/mmu_context.c
@@ -246,15 +246,15 @@ static void destroy_contexts(mm_context_t *ctx)
 static void pmd_frag_destroy(void *pmd_frag)
 {
 	int count;
-	struct page *page;
+	struct ptdesc *ptdesc;
 
-	page = virt_to_page(pmd_frag);
+	ptdesc = virt_to_ptdesc(pmd_frag);
 	/* drop all the pending references */
 	count = ((unsigned long)pmd_frag & ~PAGE_MASK) >> PMD_FRAG_SIZE_SHIFT;
 	/* We allow PTE_FRAG_NR fragments from a PTE page */
-	if (atomic_sub_and_test(PMD_FRAG_NR - count, &page->pt_frag_refcount)) {
-		pgtable_pmd_page_dtor(page);
-		__free_page(page);
+	if (atomic_sub_and_test(PMD_FRAG_NR - count, &ptdesc->pt_frag_refcount)) {
+		pagetable_pmd_dtor(ptdesc);
+		pagetable_free(ptdesc);
 	}
 }
 
diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c
index 85c84e89e3ea..1212deeabe15 100644
--- a/arch/powerpc/mm/book3s64/pgtable.c
+++ b/arch/powerpc/mm/book3s64/pgtable.c
@@ -306,22 +306,22 @@ static pmd_t *get_pmd_from_cache(struct mm_struct *mm)
 static pmd_t *__alloc_for_pmdcache(struct mm_struct *mm)
 {
 	void *ret = NULL;
-	struct page *page;
+	struct ptdesc *ptdesc;
 	gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO;
 
 	if (mm == &init_mm)
 		gfp &= ~__GFP_ACCOUNT;
-	page = alloc_page(gfp);
-	if (!page)
+	ptdesc = pagetable_alloc(gfp, 0);
+	if (!ptdesc)
 		return NULL;
-	if (!pgtable_pmd_page_ctor(page)) {
-		__free_pages(page, 0);
+	if (!pagetable_pmd_ctor(ptdesc)) {
+		pagetable_free(ptdesc);
 		return NULL;
 	}
 
-	atomic_set(&page->pt_frag_refcount, 1);
+	atomic_set(&ptdesc->pt_frag_refcount, 1);
 
-	ret = page_address(page);
+	ret = ptdesc_address(ptdesc);
 	/*
 	 * if we support only one fragment just return the
 	 * allocated page.
@@ -331,12 +331,12 @@ static pmd_t *__alloc_for_pmdcache(struct mm_struct *mm)
 
 	spin_lock(&mm->page_table_lock);
 	/*
-	 * If we find pgtable_page set, we return
+	 * If we find ptdesc_page set, we return
 	 * the allocated page with single fragment
 	 * count.
 	 */
 	if (likely(!mm->context.pmd_frag)) {
-		atomic_set(&page->pt_frag_refcount, PMD_FRAG_NR);
+		atomic_set(&ptdesc->pt_frag_refcount, PMD_FRAG_NR);
 		mm->context.pmd_frag = ret + PMD_FRAG_SIZE;
 	}
 	spin_unlock(&mm->page_table_lock);
@@ -357,15 +357,15 @@ pmd_t *pmd_fragment_alloc(struct mm_struct *mm, unsigned long vmaddr)
 
 void pmd_fragment_free(unsigned long *pmd)
 {
-	struct page *page = virt_to_page(pmd);
+	struct ptdesc *ptdesc = virt_to_ptdesc(pmd);
 
-	if (PageReserved(page))
-		return free_reserved_page(page);
+	if (pagetable_is_reserved(ptdesc))
+		return free_reserved_ptdesc(ptdesc);
 
-	BUG_ON(atomic_read(&page->pt_frag_refcount) <= 0);
-	if (atomic_dec_and_test(&page->pt_frag_refcount)) {
-		pgtable_pmd_page_dtor(page);
-		__free_page(page);
+	BUG_ON(atomic_read(&ptdesc->pt_frag_refcount) <= 0);
+	if (atomic_dec_and_test(&ptdesc->pt_frag_refcount)) {
+		pagetable_pmd_dtor(ptdesc);
+		pagetable_free(ptdesc);
 	}
 }
 
diff --git a/arch/powerpc/mm/pgtable-frag.c b/arch/powerpc/mm/pgtable-frag.c
index 20652daa1d7e..8961f1540209 100644
--- a/arch/powerpc/mm/pgtable-frag.c
+++ b/arch/powerpc/mm/pgtable-frag.c
@@ -18,15 +18,15 @@
 void pte_frag_destroy(void *pte_frag)
 {
 	int count;
-	struct page *page;
+	struct ptdesc *ptdesc;
 
-	page = virt_to_page(pte_frag);
+	ptdesc = virt_to_ptdesc(pte_frag);
 	/* drop all the pending references */
 	count = ((unsigned long)pte_frag & ~PAGE_MASK) >> PTE_FRAG_SIZE_SHIFT;
 	/* We allow PTE_FRAG_NR fragments from a PTE page */
-	if (atomic_sub_and_test(PTE_FRAG_NR - count, &page->pt_frag_refcount)) {
-		pgtable_pte_page_dtor(page);
-		__free_page(page);
+	if (atomic_sub_and_test(PTE_FRAG_NR - count, &ptdesc->pt_frag_refcount)) {
+		pagetable_pte_dtor(ptdesc);
+		pagetable_free(ptdesc);
 	}
 }
 
@@ -55,25 +55,25 @@ static pte_t *get_pte_from_cache(struct mm_struct *mm)
 static pte_t *__alloc_for_ptecache(struct mm_struct *mm, int kernel)
 {
 	void *ret = NULL;
-	struct page *page;
+	struct ptdesc *ptdesc;
 
 	if (!kernel) {
-		page = alloc_page(PGALLOC_GFP | __GFP_ACCOUNT);
-		if (!page)
+		ptdesc = pagetable_alloc(PGALLOC_GFP | __GFP_ACCOUNT, 0);
+		if (!ptdesc)
 			return NULL;
-		if (!pgtable_pte_page_ctor(page)) {
-			__free_page(page);
+		if (!pagetable_pte_ctor(ptdesc)) {
+			pagetable_free(ptdesc);
 			return NULL;
 		}
 	} else {
-		page = alloc_page(PGALLOC_GFP);
-		if (!page)
+		ptdesc = pagetable_alloc(PGALLOC_GFP, 0);
+		if (!ptdesc)
 			return NULL;
 	}
 
-	atomic_set(&page->pt_frag_refcount, 1);
+	atomic_set(&ptdesc->pt_frag_refcount, 1);
 
-	ret = page_address(page);
+	ret = ptdesc_address(ptdesc);
 	/*
 	 * if we support only one fragment just return the
 	 * allocated page.
@@ -82,12 +82,12 @@ static pte_t *__alloc_for_ptecache(struct mm_struct *mm, int kernel)
 		return ret;
 	spin_lock(&mm->page_table_lock);
 	/*
-	 * If we find pgtable_page set, we return
+	 * If we find ptdesc_page set, we return
 	 * the allocated page with single fragment
 	 * count.
 	 */
 	if (likely(!pte_frag_get(&mm->context))) {
-		atomic_set(&page->pt_frag_refcount, PTE_FRAG_NR);
+		atomic_set(&ptdesc->pt_frag_refcount, PTE_FRAG_NR);
 		pte_frag_set(&mm->context, ret + PTE_FRAG_SIZE);
 	}
 	spin_unlock(&mm->page_table_lock);
@@ -108,15 +108,15 @@ pte_t *pte_fragment_alloc(struct mm_struct *mm, int kernel)
 
 void pte_fragment_free(unsigned long *table, int kernel)
 {
-	struct page *page = virt_to_page(table);
+	struct ptdesc *ptdesc = virt_to_ptdesc(table);
 
-	if (PageReserved(page))
-		return free_reserved_page(page);
+	if (pagetable_is_reserved(ptdesc))
+		return free_reserved_ptdesc(ptdesc);
 
-	BUG_ON(atomic_read(&page->pt_frag_refcount) <= 0);
-	if (atomic_dec_and_test(&page->pt_frag_refcount)) {
+	BUG_ON(atomic_read(&ptdesc->pt_frag_refcount) <= 0);
+	if (atomic_dec_and_test(&ptdesc->pt_frag_refcount)) {
 		if (!kernel)
-			pgtable_pte_page_dtor(page);
-		__free_page(page);
+			pagetable_pte_dtor(ptdesc);
+		pagetable_free(ptdesc);
 	}
 }
-- 
2.40.1

[PATCH v6 14/33] x86: Convert various functions to use ptdescs

[Vishal Moola (Oracle)]

In order to split struct ptdesc from struct page, convert various
functions to use ptdescs.

Some of the functions use the *get*page*() helper functions. Convert
these to use pagetable_alloc() and ptdesc_address() instead to help
standardize page tables further.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
---
 arch/x86/mm/pgtable.c | 47 ++++++++++++++++++++++++++-----------------
 1 file changed, 28 insertions(+), 19 deletions(-)

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 15a8009a4480..d3a93e8766ee 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -52,7 +52,7 @@ early_param("userpte", setup_userpte);
 
 void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
 {
-	pgtable_pte_page_dtor(pte);
+	pagetable_pte_dtor(page_ptdesc(pte));
 	paravirt_release_pte(page_to_pfn(pte));
 	paravirt_tlb_remove_table(tlb, pte);
 }
@@ -60,7 +60,7 @@ void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
 #if CONFIG_PGTABLE_LEVELS > 2
 void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
 {
-	struct page *page = virt_to_page(pmd);
+	struct ptdesc *ptdesc = virt_to_ptdesc(pmd);
 	paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT);
 	/*
 	 * NOTE! For PAE, any changes to the top page-directory-pointer-table
@@ -69,8 +69,8 @@ void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
 #ifdef CONFIG_X86_PAE
 	tlb->need_flush_all = 1;
 #endif
-	pgtable_pmd_page_dtor(page);
-	paravirt_tlb_remove_table(tlb, page);
+	pagetable_pmd_dtor(ptdesc);
+	paravirt_tlb_remove_table(tlb, ptdesc_page(ptdesc));
 }
 
 #if CONFIG_PGTABLE_LEVELS > 3
@@ -92,16 +92,16 @@ void ___p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d)
 
 static inline void pgd_list_add(pgd_t *pgd)
 {
-	struct page *page = virt_to_page(pgd);
+	struct ptdesc *ptdesc = virt_to_ptdesc(pgd);
 
-	list_add(&page->lru, &pgd_list);
+	list_add(&ptdesc->pt_list, &pgd_list);
 }
 
 static inline void pgd_list_del(pgd_t *pgd)
 {
-	struct page *page = virt_to_page(pgd);
+	struct ptdesc *ptdesc = virt_to_ptdesc(pgd);
 
-	list_del(&page->lru);
+	list_del(&ptdesc->pt_list);
 }
 
 #define UNSHARED_PTRS_PER_PGD				\
@@ -112,12 +112,12 @@ static inline void pgd_list_del(pgd_t *pgd)
 
 static void pgd_set_mm(pgd_t *pgd, struct mm_struct *mm)
 {
-	virt_to_page(pgd)->pt_mm = mm;
+	virt_to_ptdesc(pgd)->pt_mm = mm;
 }
 
 struct mm_struct *pgd_page_get_mm(struct page *page)
 {
-	return page->pt_mm;
+	return page_ptdesc(page)->pt_mm;
 }
 
 static void pgd_ctor(struct mm_struct *mm, pgd_t *pgd)
@@ -213,11 +213,14 @@ void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd)
 static void free_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
 {
 	int i;
+	struct ptdesc *ptdesc;
 
 	for (i = 0; i < count; i++)
 		if (pmds[i]) {
-			pgtable_pmd_page_dtor(virt_to_page(pmds[i]));
-			free_page((unsigned long)pmds[i]);
+			ptdesc = virt_to_ptdesc(pmds[i]);
+
+			pagetable_pmd_dtor(ptdesc);
+			pagetable_free(ptdesc);
 			mm_dec_nr_pmds(mm);
 		}
 }
@@ -230,18 +233,24 @@ static int preallocate_pmds(struct mm_struct *mm, pmd_t *pmds[], int count)
 
 	if (mm == &init_mm)
 		gfp &= ~__GFP_ACCOUNT;
+	gfp &= ~__GFP_HIGHMEM;
 
 	for (i = 0; i < count; i++) {
-		pmd_t *pmd = (pmd_t *)__get_free_page(gfp);
-		if (!pmd)
+		pmd_t *pmd = NULL;
+		struct ptdesc *ptdesc = pagetable_alloc(gfp, 0);
+
+		if (!ptdesc)
 			failed = true;
-		if (pmd && !pgtable_pmd_page_ctor(virt_to_page(pmd))) {
-			free_page((unsigned long)pmd);
-			pmd = NULL;
+		if (ptdesc && !pagetable_pmd_ctor(ptdesc)) {
+			pagetable_free(ptdesc);
+			ptdesc = NULL;
 			failed = true;
 		}
-		if (pmd)
+		if (ptdesc) {
 			mm_inc_nr_pmds(mm);
+			pmd = ptdesc_address(ptdesc);
+		}
+
 		pmds[i] = pmd;
 	}
 
@@ -830,7 +839,7 @@ int pud_free_pmd_page(pud_t *pud, unsigned long addr)
 
 	free_page((unsigned long)pmd_sv);
 
-	pgtable_pmd_page_dtor(virt_to_page(pmd));
+	pagetable_pmd_dtor(virt_to_ptdesc(pmd));
 	free_page((unsigned long)pmd);
 
 	return 1;
-- 
2.40.1

[PATCH v6 15/33] s390: Convert various gmap functions to use ptdescs

[Vishal Moola (Oracle)]

In order to split struct ptdesc from struct page, convert various
functions to use ptdescs.

Some of the functions use the *get*page*() helper functions. Convert
these to use pagetable_alloc() and ptdesc_address() instead to help
standardize page tables further.

Since we're now using pagetable_free(), set _pt_s390_gaddr (which
aliases with page->mapping) to NULL in that function instead.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/s390/mm/gmap.c | 217 +++++++++++++++++++++++---------------------
 include/linux/mm.h  |   3 +
 2 files changed, 117 insertions(+), 103 deletions(-)

diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index beb4804d9ca8..8dbe0fdc0e44 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -34,7 +34,7 @@
 static struct gmap *gmap_alloc(unsigned long limit)
 {
 	struct gmap *gmap;
-	struct page *page;
+	struct ptdesc *ptdesc;
 	unsigned long *table;
 	unsigned long etype, atype;
 
@@ -67,12 +67,12 @@ static struct gmap *gmap_alloc(unsigned long limit)
 	spin_lock_init(&gmap->guest_table_lock);
 	spin_lock_init(&gmap->shadow_lock);
 	refcount_set(&gmap->ref_count, 1);
-	page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
-	if (!page)
+	ptdesc = pagetable_alloc(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
+	if (!ptdesc)
 		goto out_free;
-	page->_pt_s390_gaddr = 0;
-	list_add(&page->lru, &gmap->crst_list);
-	table = page_to_virt(page);
+	ptdesc->_pt_s390_gaddr = 0;
+	list_add(&ptdesc->pt_list, &gmap->crst_list);
+	table = ptdesc_to_virt(ptdesc);
 	crst_table_init(table, etype);
 	gmap->table = table;
 	gmap->asce = atype | _ASCE_TABLE_LENGTH |
@@ -181,25 +181,23 @@ static void gmap_rmap_radix_tree_free(struct radix_tree_root *root)
  */
 static void gmap_free(struct gmap *gmap)
 {
-	struct page *page, *next;
+	struct ptdesc *ptdesc, *next;
 
 	/* Flush tlb of all gmaps (if not already done for shadows) */
 	if (!(gmap_is_shadow(gmap) && gmap->removed))
 		gmap_flush_tlb(gmap);
 	/* Free all segment & region tables. */
-	list_for_each_entry_safe(page, next, &gmap->crst_list, lru) {
-		page->_pt_s390_gaddr = 0;
-		__free_pages(page, CRST_ALLOC_ORDER);
+	list_for_each_entry_safe(ptdesc, next, &gmap->crst_list, pt_list) {
+		pagetable_free(ptdesc);
 	}
 	gmap_radix_tree_free(&gmap->guest_to_host);
 	gmap_radix_tree_free(&gmap->host_to_guest);
 
 	/* Free additional data for a shadow gmap */
 	if (gmap_is_shadow(gmap)) {
-		/* Free all page tables. */
-		list_for_each_entry_safe(page, next, &gmap->pt_list, lru) {
-			page->_pt_s390_gaddr = 0;
-			page_table_free_pgste(page);
+		/* Free all ptdesc tables. */
+		list_for_each_entry_safe(ptdesc, next, &gmap->pt_list, pt_list) {
+			page_table_free_pgste(ptdesc_page(ptdesc));
 		}
 		gmap_rmap_radix_tree_free(&gmap->host_to_rmap);
 		/* Release reference to the parent */
@@ -308,28 +306,27 @@ EXPORT_SYMBOL_GPL(gmap_get_enabled);
 static int gmap_alloc_table(struct gmap *gmap, unsigned long *table,
 			    unsigned long init, unsigned long gaddr)
 {
-	struct page *page;
+	struct ptdesc *ptdesc;
 	unsigned long *new;
 
 	/* since we dont free the gmap table until gmap_free we can unlock */
-	page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
-	if (!page)
+	ptdesc = pagetable_alloc(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
+	if (!ptdesc)
 		return -ENOMEM;
-	new = page_to_virt(page);
+	new = ptdesc_to_virt(ptdesc);
 	crst_table_init(new, init);
 	spin_lock(&gmap->guest_table_lock);
 	if (*table & _REGION_ENTRY_INVALID) {
-		list_add(&page->lru, &gmap->crst_list);
+		list_add(&ptdesc->pt_list, &gmap->crst_list);
 		*table = __pa(new) | _REGION_ENTRY_LENGTH |
 			(*table & _REGION_ENTRY_TYPE_MASK);
-		page->_pt_s390_gaddr = gaddr;
-		page = NULL;
+		ptdesc->_pt_s390_gaddr = gaddr;
+		ptdesc = NULL;
 	}
 	spin_unlock(&gmap->guest_table_lock);
-	if (page) {
-		page->_pt_s390_gaddr = 0;
-		__free_pages(page, CRST_ALLOC_ORDER);
-	}
+	if (ptdesc)
+		pagetable_free(ptdesc);
+
 	return 0;
 }
 
@@ -341,15 +338,15 @@ static int gmap_alloc_table(struct gmap *gmap, unsigned long *table,
  */
 static unsigned long __gmap_segment_gaddr(unsigned long *entry)
 {
-	struct page *page;
+	struct ptdesc *ptdesc;
 	unsigned long offset, mask;
 
 	offset = (unsigned long) entry / sizeof(unsigned long);
 	offset = (offset & (PTRS_PER_PMD - 1)) * PMD_SIZE;
 	mask = ~(PTRS_PER_PMD * sizeof(pmd_t) - 1);
-	page = virt_to_page((void *)((unsigned long) entry & mask));
+	ptdesc = virt_to_ptdesc((void *)((unsigned long) entry & mask));
 
-	return page->_pt_s390_gaddr + offset;
+	return ptdesc->_pt_s390_gaddr + offset;
 }
 
 /**
@@ -1345,6 +1342,7 @@ static void gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr)
 	unsigned long *ste;
 	phys_addr_t sto, pgt;
 	struct page *page;
+	struct ptdesc *ptdesc;
 
 	BUG_ON(!gmap_is_shadow(sg));
 	ste = gmap_table_walk(sg, raddr, 1); /* get segment pointer */
@@ -1358,9 +1356,10 @@ static void gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr)
 	__gmap_unshadow_pgt(sg, raddr, __va(pgt));
 	/* Free page table */
 	page = phys_to_page(pgt);
-	list_del(&page->lru);
-	page->_pt_s390_gaddr = 0;
-	page_table_free_pgste(page);
+
+	ptdesc = page_ptdesc(page);
+	list_del(&ptdesc->pt_list);
+	page_table_free_pgste(ptdesc_page(ptdesc));
 }
 
 /**
@@ -1374,9 +1373,10 @@ static void gmap_unshadow_pgt(struct gmap *sg, unsigned long raddr)
 static void __gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr,
 				unsigned long *sgt)
 {
-	struct page *page;
 	phys_addr_t pgt;
 	int i;
+	struct page *page;
+	struct ptdesc *ptdesc;
 
 	BUG_ON(!gmap_is_shadow(sg));
 	for (i = 0; i < _CRST_ENTRIES; i++, raddr += _SEGMENT_SIZE) {
@@ -1387,9 +1387,10 @@ static void __gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr,
 		__gmap_unshadow_pgt(sg, raddr, __va(pgt));
 		/* Free page table */
 		page = phys_to_page(pgt);
-		list_del(&page->lru);
-		page->_pt_s390_gaddr = 0;
-		page_table_free_pgste(page);
+
+		ptdesc = page_ptdesc(page);
+		list_del(&ptdesc->pt_list);
+		page_table_free_pgste(ptdesc_page(ptdesc));
 	}
 }
 
@@ -1405,6 +1406,7 @@ static void gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr)
 	unsigned long r3o, *r3e;
 	phys_addr_t sgt;
 	struct page *page;
+	struct ptdesc *ptdesc;
 
 	BUG_ON(!gmap_is_shadow(sg));
 	r3e = gmap_table_walk(sg, raddr, 2); /* get region-3 pointer */
@@ -1418,9 +1420,10 @@ static void gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr)
 	__gmap_unshadow_sgt(sg, raddr, __va(sgt));
 	/* Free segment table */
 	page = phys_to_page(sgt);
-	list_del(&page->lru);
-	page->_pt_s390_gaddr = 0;
-	__free_pages(page, CRST_ALLOC_ORDER);
+
+	ptdesc = page_ptdesc(page);
+	list_del(&ptdesc->pt_list);
+	pagetable_free(ptdesc);
 }
 
 /**
@@ -1434,9 +1437,10 @@ static void gmap_unshadow_sgt(struct gmap *sg, unsigned long raddr)
 static void __gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr,
 				unsigned long *r3t)
 {
-	struct page *page;
 	phys_addr_t sgt;
 	int i;
+	struct page *page;
+	struct ptdesc *ptdesc;
 
 	BUG_ON(!gmap_is_shadow(sg));
 	for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION3_SIZE) {
@@ -1447,9 +1451,10 @@ static void __gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr,
 		__gmap_unshadow_sgt(sg, raddr, __va(sgt));
 		/* Free segment table */
 		page = phys_to_page(sgt);
-		list_del(&page->lru);
-		page->_pt_s390_gaddr = 0;
-		__free_pages(page, CRST_ALLOC_ORDER);
+
+		ptdesc = page_ptdesc(page);
+		list_del(&ptdesc->pt_list);
+		pagetable_free(ptdesc);
 	}
 }
 
@@ -1465,6 +1470,7 @@ static void gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr)
 	unsigned long r2o, *r2e;
 	phys_addr_t r3t;
 	struct page *page;
+	struct ptdesc *ptdesc;
 
 	BUG_ON(!gmap_is_shadow(sg));
 	r2e = gmap_table_walk(sg, raddr, 3); /* get region-2 pointer */
@@ -1478,9 +1484,10 @@ static void gmap_unshadow_r3t(struct gmap *sg, unsigned long raddr)
 	__gmap_unshadow_r3t(sg, raddr, __va(r3t));
 	/* Free region 3 table */
 	page = phys_to_page(r3t);
-	list_del(&page->lru);
-	page->_pt_s390_gaddr = 0;
-	__free_pages(page, CRST_ALLOC_ORDER);
+
+	ptdesc = page_ptdesc(page);
+	list_del(&ptdesc->pt_list);
+	pagetable_free(ptdesc);
 }
 
 /**
@@ -1495,8 +1502,9 @@ static void __gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr,
 				unsigned long *r2t)
 {
 	phys_addr_t r3t;
-	struct page *page;
 	int i;
+	struct page *page;
+	struct ptdesc *ptdesc;
 
 	BUG_ON(!gmap_is_shadow(sg));
 	for (i = 0; i < _CRST_ENTRIES; i++, raddr += _REGION2_SIZE) {
@@ -1507,9 +1515,10 @@ static void __gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr,
 		__gmap_unshadow_r3t(sg, raddr, __va(r3t));
 		/* Free region 3 table */
 		page = phys_to_page(r3t);
-		list_del(&page->lru);
-		page->_pt_s390_gaddr = 0;
-		__free_pages(page, CRST_ALLOC_ORDER);
+
+		ptdesc = page_ptdesc(page);
+		list_del(&ptdesc->pt_list);
+		pagetable_free(ptdesc);
 	}
 }
 
@@ -1525,6 +1534,7 @@ static void gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr)
 	unsigned long r1o, *r1e;
 	struct page *page;
 	phys_addr_t r2t;
+	struct ptdesc *ptdesc;
 
 	BUG_ON(!gmap_is_shadow(sg));
 	r1e = gmap_table_walk(sg, raddr, 4); /* get region-1 pointer */
@@ -1538,9 +1548,10 @@ static void gmap_unshadow_r2t(struct gmap *sg, unsigned long raddr)
 	__gmap_unshadow_r2t(sg, raddr, __va(r2t));
 	/* Free region 2 table */
 	page = phys_to_page(r2t);
-	list_del(&page->lru);
-	page->_pt_s390_gaddr = 0;
-	__free_pages(page, CRST_ALLOC_ORDER);
+
+	ptdesc = page_ptdesc(page);
+	list_del(&ptdesc->pt_list);
+	pagetable_free(ptdesc);
 }
 
 /**
@@ -1558,6 +1569,7 @@ static void __gmap_unshadow_r1t(struct gmap *sg, unsigned long raddr,
 	struct page *page;
 	phys_addr_t r2t;
 	int i;
+	struct ptdesc *ptdesc;
 
 	BUG_ON(!gmap_is_shadow(sg));
 	asce = __pa(r1t) | _ASCE_TYPE_REGION1;
@@ -1571,9 +1583,10 @@ static void __gmap_unshadow_r1t(struct gmap *sg, unsigned long raddr,
 		r1t[i] = _REGION1_ENTRY_EMPTY;
 		/* Free region 2 table */
 		page = phys_to_page(r2t);
-		list_del(&page->lru);
-		page->_pt_s390_gaddr = 0;
-		__free_pages(page, CRST_ALLOC_ORDER);
+
+		ptdesc = page_ptdesc(page);
+		list_del(&ptdesc->pt_list);
+		pagetable_free(ptdesc);
 	}
 }
 
@@ -1770,18 +1783,18 @@ int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t,
 	unsigned long raddr, origin, offset, len;
 	unsigned long *table;
 	phys_addr_t s_r2t;
-	struct page *page;
+	struct ptdesc *ptdesc;
 	int rc;
 
 	BUG_ON(!gmap_is_shadow(sg));
 	/* Allocate a shadow region second table */
-	page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
-	if (!page)
+	ptdesc = pagetable_alloc(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
+	if (!ptdesc)
 		return -ENOMEM;
-	page->_pt_s390_gaddr = r2t & _REGION_ENTRY_ORIGIN;
+	ptdesc->_pt_s390_gaddr = r2t & _REGION_ENTRY_ORIGIN;
 	if (fake)
-		page->_pt_s390_gaddr |= GMAP_SHADOW_FAKE_TABLE;
-	s_r2t = page_to_phys(page);
+		ptdesc->_pt_s390_gaddr |= GMAP_SHADOW_FAKE_TABLE;
+	s_r2t = page_to_phys(ptdesc_page(ptdesc));
 	/* Install shadow region second table */
 	spin_lock(&sg->guest_table_lock);
 	table = gmap_table_walk(sg, saddr, 4); /* get region-1 pointer */
@@ -1802,7 +1815,7 @@ int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t,
 		 _REGION_ENTRY_TYPE_R1 | _REGION_ENTRY_INVALID;
 	if (sg->edat_level >= 1)
 		*table |= (r2t & _REGION_ENTRY_PROTECT);
-	list_add(&page->lru, &sg->crst_list);
+	list_add(&ptdesc->pt_list, &sg->crst_list);
 	if (fake) {
 		/* nothing to protect for fake tables */
 		*table &= ~_REGION_ENTRY_INVALID;
@@ -1830,8 +1843,7 @@ int gmap_shadow_r2t(struct gmap *sg, unsigned long saddr, unsigned long r2t,
 	return rc;
 out_free:
 	spin_unlock(&sg->guest_table_lock);
-	page->_pt_s390_gaddr = 0;
-	__free_pages(page, CRST_ALLOC_ORDER);
+	pagetable_free(ptdesc);
 	return rc;
 }
 EXPORT_SYMBOL_GPL(gmap_shadow_r2t);
@@ -1855,18 +1867,18 @@ int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t,
 	unsigned long raddr, origin, offset, len;
 	unsigned long *table;
 	phys_addr_t s_r3t;
-	struct page *page;
+	struct ptdesc *ptdesc;
 	int rc;
 
 	BUG_ON(!gmap_is_shadow(sg));
 	/* Allocate a shadow region second table */
-	page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
-	if (!page)
+	ptdesc = pagetable_alloc(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
+	if (!ptdesc)
 		return -ENOMEM;
-	page->_pt_s390_gaddr = r3t & _REGION_ENTRY_ORIGIN;
+	ptdesc->_pt_s390_gaddr = r3t & _REGION_ENTRY_ORIGIN;
 	if (fake)
-		page->_pt_s390_gaddr |= GMAP_SHADOW_FAKE_TABLE;
-	s_r3t = page_to_phys(page);
+		ptdesc->_pt_s390_gaddr |= GMAP_SHADOW_FAKE_TABLE;
+	s_r3t = page_to_phys(ptdesc_page(ptdesc));
 	/* Install shadow region second table */
 	spin_lock(&sg->guest_table_lock);
 	table = gmap_table_walk(sg, saddr, 3); /* get region-2 pointer */
@@ -1887,7 +1899,7 @@ int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t,
 		 _REGION_ENTRY_TYPE_R2 | _REGION_ENTRY_INVALID;
 	if (sg->edat_level >= 1)
 		*table |= (r3t & _REGION_ENTRY_PROTECT);
-	list_add(&page->lru, &sg->crst_list);
+	list_add(&ptdesc->pt_list, &sg->crst_list);
 	if (fake) {
 		/* nothing to protect for fake tables */
 		*table &= ~_REGION_ENTRY_INVALID;
@@ -1915,8 +1927,7 @@ int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t,
 	return rc;
 out_free:
 	spin_unlock(&sg->guest_table_lock);
-	page->_pt_s390_gaddr = 0;
-	__free_pages(page, CRST_ALLOC_ORDER);
+	pagetable_free(ptdesc);
 	return rc;
 }
 EXPORT_SYMBOL_GPL(gmap_shadow_r3t);
@@ -1940,18 +1951,18 @@ int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt,
 	unsigned long raddr, origin, offset, len;
 	unsigned long *table;
 	phys_addr_t s_sgt;
-	struct page *page;
+	struct ptdesc *ptdesc;
 	int rc;
 
 	BUG_ON(!gmap_is_shadow(sg) || (sgt & _REGION3_ENTRY_LARGE));
 	/* Allocate a shadow segment table */
-	page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
-	if (!page)
+	ptdesc = pagetable_alloc(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
+	if (!ptdesc)
 		return -ENOMEM;
-	page->_pt_s390_gaddr = sgt & _REGION_ENTRY_ORIGIN;
+	ptdesc->_pt_s390_gaddr = sgt & _REGION_ENTRY_ORIGIN;
 	if (fake)
-		page->_pt_s390_gaddr |= GMAP_SHADOW_FAKE_TABLE;
-	s_sgt = page_to_phys(page);
+		ptdesc->_pt_s390_gaddr |= GMAP_SHADOW_FAKE_TABLE;
+	s_sgt = page_to_phys(ptdesc_page(ptdesc));
 	/* Install shadow region second table */
 	spin_lock(&sg->guest_table_lock);
 	table = gmap_table_walk(sg, saddr, 2); /* get region-3 pointer */
@@ -1972,7 +1983,7 @@ int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt,
 		 _REGION_ENTRY_TYPE_R3 | _REGION_ENTRY_INVALID;
 	if (sg->edat_level >= 1)
 		*table |= sgt & _REGION_ENTRY_PROTECT;
-	list_add(&page->lru, &sg->crst_list);
+	list_add(&ptdesc->pt_list, &sg->crst_list);
 	if (fake) {
 		/* nothing to protect for fake tables */
 		*table &= ~_REGION_ENTRY_INVALID;
@@ -2000,8 +2011,7 @@ int gmap_shadow_sgt(struct gmap *sg, unsigned long saddr, unsigned long sgt,
 	return rc;
 out_free:
 	spin_unlock(&sg->guest_table_lock);
-	page->_pt_s390_gaddr = 0;
-	__free_pages(page, CRST_ALLOC_ORDER);
+	pagetable_free(ptdesc);
 	return rc;
 }
 EXPORT_SYMBOL_GPL(gmap_shadow_sgt);
@@ -2024,8 +2034,9 @@ int gmap_shadow_pgt_lookup(struct gmap *sg, unsigned long saddr,
 			   int *fake)
 {
 	unsigned long *table;
-	struct page *page;
 	int rc;
+	struct page *page;
+	struct ptdesc *ptdesc;
 
 	BUG_ON(!gmap_is_shadow(sg));
 	spin_lock(&sg->guest_table_lock);
@@ -2033,9 +2044,10 @@ int gmap_shadow_pgt_lookup(struct gmap *sg, unsigned long saddr,
 	if (table && !(*table & _SEGMENT_ENTRY_INVALID)) {
 		/* Shadow page tables are full pages (pte+pgste) */
 		page = pfn_to_page(*table >> PAGE_SHIFT);
-		*pgt = page->_pt_s390_gaddr & ~GMAP_SHADOW_FAKE_TABLE;
+		ptdesc = page_ptdesc(page);
+		*pgt = ptdesc->_pt_s390_gaddr & ~GMAP_SHADOW_FAKE_TABLE;
 		*dat_protection = !!(*table & _SEGMENT_ENTRY_PROTECT);
-		*fake = !!(page->_pt_s390_gaddr & GMAP_SHADOW_FAKE_TABLE);
+		*fake = !!(ptdesc->_pt_s390_gaddr & GMAP_SHADOW_FAKE_TABLE);
 		rc = 0;
 	} else  {
 		rc = -EAGAIN;
@@ -2064,19 +2076,19 @@ int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt,
 {
 	unsigned long raddr, origin;
 	unsigned long *table;
-	struct page *page;
+	struct ptdesc *ptdesc;
 	phys_addr_t s_pgt;
 	int rc;
 
 	BUG_ON(!gmap_is_shadow(sg) || (pgt & _SEGMENT_ENTRY_LARGE));
 	/* Allocate a shadow page table */
-	page = page_table_alloc_pgste(sg->mm);
-	if (!page)
+	ptdesc = page_ptdesc(page_table_alloc_pgste(sg->mm));
+	if (!ptdesc)
 		return -ENOMEM;
-	page->_pt_s390_gaddr = pgt & _SEGMENT_ENTRY_ORIGIN;
+	ptdesc->_pt_s390_gaddr = pgt & _SEGMENT_ENTRY_ORIGIN;
 	if (fake)
-		page->_pt_s390_gaddr |= GMAP_SHADOW_FAKE_TABLE;
-	s_pgt = page_to_phys(page);
+		ptdesc->_pt_s390_gaddr |= GMAP_SHADOW_FAKE_TABLE;
+	s_pgt = page_to_phys(ptdesc_page(ptdesc));
 	/* Install shadow page table */
 	spin_lock(&sg->guest_table_lock);
 	table = gmap_table_walk(sg, saddr, 1); /* get segment pointer */
@@ -2094,7 +2106,7 @@ int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt,
 	/* mark as invalid as long as the parent table is not protected */
 	*table = (unsigned long) s_pgt | _SEGMENT_ENTRY |
 		 (pgt & _SEGMENT_ENTRY_PROTECT) | _SEGMENT_ENTRY_INVALID;
-	list_add(&page->lru, &sg->pt_list);
+	list_add(&ptdesc->pt_list, &sg->pt_list);
 	if (fake) {
 		/* nothing to protect for fake tables */
 		*table &= ~_SEGMENT_ENTRY_INVALID;
@@ -2120,8 +2132,7 @@ int gmap_shadow_pgt(struct gmap *sg, unsigned long saddr, unsigned long pgt,
 	return rc;
 out_free:
 	spin_unlock(&sg->guest_table_lock);
-	page->_pt_s390_gaddr = 0;
-	page_table_free_pgste(page);
+	page_table_free_pgste(ptdesc_page(ptdesc));
 	return rc;
 
 }
@@ -2821,11 +2832,11 @@ EXPORT_SYMBOL_GPL(__s390_uv_destroy_range);
  */
 void s390_unlist_old_asce(struct gmap *gmap)
 {
-	struct page *old;
+	struct ptdesc *old;
 
-	old = virt_to_page(gmap->table);
+	old = virt_to_ptdesc(gmap->table);
 	spin_lock(&gmap->guest_table_lock);
-	list_del(&old->lru);
+	list_del(&old->pt_list);
 	/*
 	 * Sometimes the topmost page might need to be "removed" multiple
 	 * times, for example if the VM is rebooted into secure mode several
@@ -2840,7 +2851,7 @@ void s390_unlist_old_asce(struct gmap *gmap)
 	 * pointers, so list_del can work (and do nothing) without
 	 * dereferencing stale or invalid pointers.
 	 */
-	INIT_LIST_HEAD(&old->lru);
+	INIT_LIST_HEAD(&old->pt_list);
 	spin_unlock(&gmap->guest_table_lock);
 }
 EXPORT_SYMBOL_GPL(s390_unlist_old_asce);
@@ -2861,7 +2872,7 @@ EXPORT_SYMBOL_GPL(s390_unlist_old_asce);
 int s390_replace_asce(struct gmap *gmap)
 {
 	unsigned long asce;
-	struct page *page;
+	struct ptdesc *ptdesc;
 	void *table;
 
 	s390_unlist_old_asce(gmap);
@@ -2870,10 +2881,10 @@ int s390_replace_asce(struct gmap *gmap)
 	if ((gmap->asce & _ASCE_TYPE_MASK) == _ASCE_TYPE_SEGMENT)
 		return -EINVAL;
 
-	page = alloc_pages(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
-	if (!page)
+	ptdesc = pagetable_alloc(GFP_KERNEL_ACCOUNT, CRST_ALLOC_ORDER);
+	if (!ptdesc)
 		return -ENOMEM;
-	table = page_to_virt(page);
+	table = ptdesc_to_virt(ptdesc);
 	memcpy(table, gmap->table, 1UL << (CRST_ALLOC_ORDER + PAGE_SHIFT));
 
 	/*
@@ -2882,7 +2893,7 @@ int s390_replace_asce(struct gmap *gmap)
 	 * it will be freed when the VM is torn down.
 	 */
 	spin_lock(&gmap->guest_table_lock);
-	list_add(&page->lru, &gmap->crst_list);
+	list_add(&ptdesc->pt_list, &gmap->crst_list);
 	spin_unlock(&gmap->guest_table_lock);
 
 	/* Set new table origin while preserving existing ASCE control bits */
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 356e79984cf9..0e4d5f6d10e5 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2792,6 +2792,9 @@ static inline void pagetable_free(struct ptdesc *pt)
 {
 	struct page *page = ptdesc_page(pt);
 
+	/* set page->mapping to NULL since s390 gmap may have used it */
+	pt->_pt_s390_gaddr = 0;
+
 	__free_pages(page, compound_order(page));
 }
 
-- 
2.40.1

[PATCH v6 16/33] s390: Convert various pgalloc functions to use ptdescs

[Vishal Moola (Oracle)]

As part of the conversions to replace pgtable constructor/destructors with
ptdesc equivalents, convert various page table functions to use ptdescs.

Some of the functions use the *get*page*() helper functions. Convert
these to use pagetable_alloc() and ptdesc_address() instead to help
standardize page tables further.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/s390/include/asm/pgalloc.h |   4 +-
 arch/s390/include/asm/tlb.h     |   4 +-
 arch/s390/mm/pgalloc.c          | 108 ++++++++++++++++----------------
 3 files changed, 59 insertions(+), 57 deletions(-)

diff --git a/arch/s390/include/asm/pgalloc.h b/arch/s390/include/asm/pgalloc.h
index 17eb618f1348..00ad9b88fda9 100644
--- a/arch/s390/include/asm/pgalloc.h
+++ b/arch/s390/include/asm/pgalloc.h
@@ -86,7 +86,7 @@ static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long vmaddr)
 	if (!table)
 		return NULL;
 	crst_table_init(table, _SEGMENT_ENTRY_EMPTY);
-	if (!pgtable_pmd_page_ctor(virt_to_page(table))) {
+	if (!pagetable_pmd_ctor(virt_to_ptdesc(table))) {
 		crst_table_free(mm, table);
 		return NULL;
 	}
@@ -97,7 +97,7 @@ static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
 {
 	if (mm_pmd_folded(mm))
 		return;
-	pgtable_pmd_page_dtor(virt_to_page(pmd));
+	pagetable_pmd_dtor(virt_to_ptdesc(pmd));
 	crst_table_free(mm, (unsigned long *) pmd);
 }
 
diff --git a/arch/s390/include/asm/tlb.h b/arch/s390/include/asm/tlb.h
index b91f4a9b044c..383b1f91442c 100644
--- a/arch/s390/include/asm/tlb.h
+++ b/arch/s390/include/asm/tlb.h
@@ -89,12 +89,12 @@ static inline void pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd,
 {
 	if (mm_pmd_folded(tlb->mm))
 		return;
-	pgtable_pmd_page_dtor(virt_to_page(pmd));
+	pagetable_pmd_dtor(virt_to_ptdesc(pmd));
 	__tlb_adjust_range(tlb, address, PAGE_SIZE);
 	tlb->mm->context.flush_mm = 1;
 	tlb->freed_tables = 1;
 	tlb->cleared_puds = 1;
-	tlb_remove_table(tlb, pmd);
+	tlb_remove_ptdesc(tlb, pmd);
 }
 
 /*
diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c
index 66ab68db9842..79b1c2458d85 100644
--- a/arch/s390/mm/pgalloc.c
+++ b/arch/s390/mm/pgalloc.c
@@ -43,17 +43,17 @@ __initcall(page_table_register_sysctl);
 
 unsigned long *crst_table_alloc(struct mm_struct *mm)
 {
-	struct page *page = alloc_pages(GFP_KERNEL, CRST_ALLOC_ORDER);
+	struct ptdesc *ptdesc = pagetable_alloc(GFP_KERNEL, CRST_ALLOC_ORDER);
 
-	if (!page)
+	if (!ptdesc)
 		return NULL;
-	arch_set_page_dat(page, CRST_ALLOC_ORDER);
-	return (unsigned long *) page_to_virt(page);
+	arch_set_page_dat(ptdesc_page(ptdesc), CRST_ALLOC_ORDER);
+	return (unsigned long *) ptdesc_to_virt(ptdesc);
 }
 
 void crst_table_free(struct mm_struct *mm, unsigned long *table)
 {
-	free_pages((unsigned long)table, CRST_ALLOC_ORDER);
+	pagetable_free(virt_to_ptdesc(table));
 }
 
 static void __crst_table_upgrade(void *arg)
@@ -140,21 +140,21 @@ static inline unsigned int atomic_xor_bits(atomic_t *v, unsigned int bits)
 
 struct page *page_table_alloc_pgste(struct mm_struct *mm)
 {
-	struct page *page;
+	struct ptdesc *ptdesc;
 	u64 *table;
 
-	page = alloc_page(GFP_KERNEL);
-	if (page) {
-		table = (u64 *)page_to_virt(page);
+	ptdesc = pagetable_alloc(GFP_KERNEL, 0);
+	if (ptdesc) {
+		table = (u64 *)ptdesc_to_virt(ptdesc);
 		memset64(table, _PAGE_INVALID, PTRS_PER_PTE);
 		memset64(table + PTRS_PER_PTE, 0, PTRS_PER_PTE);
 	}
-	return page;
+	return ptdesc_page(ptdesc);
 }
 
 void page_table_free_pgste(struct page *page)
 {
-	__free_page(page);
+	pagetable_free(page_ptdesc(page));
 }
 
 #endif /* CONFIG_PGSTE */
@@ -233,7 +233,7 @@ void page_table_free_pgste(struct page *page)
 unsigned long *page_table_alloc(struct mm_struct *mm)
 {
 	unsigned long *table;
-	struct page *page;
+	struct ptdesc *ptdesc;
 	unsigned int mask, bit;
 
 	/* Try to get a fragment of a 4K page as a 2K page table */
@@ -241,9 +241,9 @@ unsigned long *page_table_alloc(struct mm_struct *mm)
 		table = NULL;
 		spin_lock_bh(&mm->context.lock);
 		if (!list_empty(&mm->context.pgtable_list)) {
-			page = list_first_entry(&mm->context.pgtable_list,
-						struct page, lru);
-			mask = atomic_read(&page->_refcount) >> 24;
+			ptdesc = list_first_entry(&mm->context.pgtable_list,
+						struct ptdesc, pt_list);
+			mask = atomic_read(&ptdesc->_refcount) >> 24;
 			/*
 			 * The pending removal bits must also be checked.
 			 * Failure to do so might lead to an impossible
@@ -255,13 +255,13 @@ unsigned long *page_table_alloc(struct mm_struct *mm)
 			 */
 			mask = (mask | (mask >> 4)) & 0x03U;
 			if (mask != 0x03U) {
-				table = (unsigned long *) page_to_virt(page);
+				table = (unsigned long *) ptdesc_to_virt(ptdesc);
 				bit = mask & 1;		/* =1 -> second 2K */
 				if (bit)
 					table += PTRS_PER_PTE;
-				atomic_xor_bits(&page->_refcount,
+				atomic_xor_bits(&ptdesc->_refcount,
 							0x01U << (bit + 24));
-				list_del(&page->lru);
+				list_del(&ptdesc->pt_list);
 			}
 		}
 		spin_unlock_bh(&mm->context.lock);
@@ -269,27 +269,27 @@ unsigned long *page_table_alloc(struct mm_struct *mm)
 			return table;
 	}
 	/* Allocate a fresh page */
-	page = alloc_page(GFP_KERNEL);
-	if (!page)
+	ptdesc = pagetable_alloc(GFP_KERNEL, 0);
+	if (!ptdesc)
 		return NULL;
-	if (!pgtable_pte_page_ctor(page)) {
-		__free_page(page);
+	if (!pagetable_pte_ctor(ptdesc)) {
+		pagetable_free(ptdesc);
 		return NULL;
 	}
-	arch_set_page_dat(page, 0);
+	arch_set_page_dat(ptdesc_page(ptdesc), 0);
 	/* Initialize page table */
-	table = (unsigned long *) page_to_virt(page);
+	table = (unsigned long *) ptdesc_to_virt(ptdesc);
 	if (mm_alloc_pgste(mm)) {
 		/* Return 4K page table with PGSTEs */
-		atomic_xor_bits(&page->_refcount, 0x03U << 24);
+		atomic_xor_bits(&ptdesc->_refcount, 0x03U << 24);
 		memset64((u64 *)table, _PAGE_INVALID, PTRS_PER_PTE);
 		memset64((u64 *)table + PTRS_PER_PTE, 0, PTRS_PER_PTE);
 	} else {
 		/* Return the first 2K fragment of the page */
-		atomic_xor_bits(&page->_refcount, 0x01U << 24);
+		atomic_xor_bits(&ptdesc->_refcount, 0x01U << 24);
 		memset64((u64 *)table, _PAGE_INVALID, 2 * PTRS_PER_PTE);
 		spin_lock_bh(&mm->context.lock);
-		list_add(&page->lru, &mm->context.pgtable_list);
+		list_add(&ptdesc->pt_list, &mm->context.pgtable_list);
 		spin_unlock_bh(&mm->context.lock);
 	}
 	return table;
@@ -311,9 +311,8 @@ static void page_table_release_check(struct page *page, void *table,
 void page_table_free(struct mm_struct *mm, unsigned long *table)
 {
 	unsigned int mask, bit, half;
-	struct page *page;
+	struct ptdesc *ptdesc = virt_to_ptdesc(table);
 
-	page = virt_to_page(table);
 	if (!mm_alloc_pgste(mm)) {
 		/* Free 2K page table fragment of a 4K page */
 		bit = ((unsigned long) table & ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t));
@@ -323,42 +322,41 @@ void page_table_free(struct mm_struct *mm, unsigned long *table)
 		 * will happen outside of the critical section from this
 		 * function or from __tlb_remove_table()
 		 */
-		mask = atomic_xor_bits(&page->_refcount, 0x11U << (bit + 24));
+		mask = atomic_xor_bits(&ptdesc->_refcount, 0x11U << (bit + 24));
 		mask >>= 24;
 		if (mask & 0x03U)
-			list_add(&page->lru, &mm->context.pgtable_list);
+			list_add(&ptdesc->pt_list, &mm->context.pgtable_list);
 		else
-			list_del(&page->lru);
+			list_del(&ptdesc->pt_list);
 		spin_unlock_bh(&mm->context.lock);
-		mask = atomic_xor_bits(&page->_refcount, 0x10U << (bit + 24));
+		mask = atomic_xor_bits(&ptdesc->_refcount, 0x10U << (bit + 24));
 		mask >>= 24;
 		if (mask != 0x00U)
 			return;
 		half = 0x01U << bit;
 	} else {
 		half = 0x03U;
-		mask = atomic_xor_bits(&page->_refcount, 0x03U << 24);
+		mask = atomic_xor_bits(&ptdesc->_refcount, 0x03U << 24);
 		mask >>= 24;
 	}
 
-	page_table_release_check(page, table, half, mask);
-	pgtable_pte_page_dtor(page);
-	__free_page(page);
+	page_table_release_check(ptdesc_page(ptdesc), table, half, mask);
+	pagetable_pte_dtor(ptdesc);
+	pagetable_free(ptdesc);
 }
 
 void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table,
 			 unsigned long vmaddr)
 {
 	struct mm_struct *mm;
-	struct page *page;
 	unsigned int bit, mask;
+	struct ptdesc *ptdesc = virt_to_ptdesc(table);
 
 	mm = tlb->mm;
-	page = virt_to_page(table);
 	if (mm_alloc_pgste(mm)) {
 		gmap_unlink(mm, table, vmaddr);
 		table = (unsigned long *) ((unsigned long)table | 0x03U);
-		tlb_remove_table(tlb, table);
+		tlb_remove_ptdesc(tlb, table);
 		return;
 	}
 	bit = ((unsigned long) table & ~PAGE_MASK) / (PTRS_PER_PTE*sizeof(pte_t));
@@ -368,12 +366,12 @@ void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table,
 	 * outside of the critical section from __tlb_remove_table() or from
 	 * page_table_free()
 	 */
-	mask = atomic_xor_bits(&page->_refcount, 0x11U << (bit + 24));
+	mask = atomic_xor_bits(&ptdesc->_refcount, 0x11U << (bit + 24));
 	mask >>= 24;
 	if (mask & 0x03U)
-		list_add_tail(&page->lru, &mm->context.pgtable_list);
+		list_add_tail(&ptdesc->pt_list, &mm->context.pgtable_list);
 	else
-		list_del(&page->lru);
+		list_del(&ptdesc->pt_list);
 	spin_unlock_bh(&mm->context.lock);
 	table = (unsigned long *) ((unsigned long) table | (0x01U << bit));
 	tlb_remove_table(tlb, table);
@@ -383,7 +381,7 @@ void __tlb_remove_table(void *_table)
 {
 	unsigned int mask = (unsigned long) _table & 0x03U, half = mask;
 	void *table = (void *)((unsigned long) _table ^ mask);
-	struct page *page = virt_to_page(table);
+	struct ptdesc *ptdesc = virt_to_ptdesc(table);
 
 	switch (half) {
 	case 0x00U:	/* pmd, pud, or p4d */
@@ -391,20 +389,20 @@ void __tlb_remove_table(void *_table)
 		return;
 	case 0x01U:	/* lower 2K of a 4K page table */
 	case 0x02U:	/* higher 2K of a 4K page table */
-		mask = atomic_xor_bits(&page->_refcount, mask << (4 + 24));
+		mask = atomic_xor_bits(&ptdesc->_refcount, mask << (4 + 24));
 		mask >>= 24;
 		if (mask != 0x00U)
 			return;
 		break;
 	case 0x03U:	/* 4K page table with pgstes */
-		mask = atomic_xor_bits(&page->_refcount, 0x03U << 24);
+		mask = atomic_xor_bits(&ptdesc->_refcount, 0x03U << 24);
 		mask >>= 24;
 		break;
 	}
 
-	page_table_release_check(page, table, half, mask);
-	pgtable_pte_page_dtor(page);
-	__free_page(page);
+	page_table_release_check(ptdesc_page(ptdesc), table, half, mask);
+	pagetable_pte_dtor(ptdesc);
+	pagetable_free(ptdesc);
 }
 
 /*
@@ -432,16 +430,20 @@ static void base_pgt_free(unsigned long *table)
 static unsigned long *base_crst_alloc(unsigned long val)
 {
 	unsigned long *table;
+	struct ptdesc *ptdesc;
 
-	table =	(unsigned long *)__get_free_pages(GFP_KERNEL, CRST_ALLOC_ORDER);
-	if (table)
-		crst_table_init(table, val);
+	ptdesc = pagetable_alloc(GFP_KERNEL & ~__GFP_HIGHMEM, CRST_ALLOC_ORDER);
+	if (!ptdesc)
+		return NULL;
+	table = ptdesc_address(ptdesc);
+
+	crst_table_init(table, val);
 	return table;
 }
 
 static void base_crst_free(unsigned long *table)
 {
-	free_pages((unsigned long)table, CRST_ALLOC_ORDER);
+	pagetable_free(virt_to_ptdesc(table));
 }
 
 #define BASE_ADDR_END_FUNC(NAME, SIZE)					\
-- 
2.40.1

[PATCH v6 17/33] mm: Remove page table members from struct page

[Vishal Moola (Oracle)]

The page table members are now split out into their own ptdesc struct.
Remove them from struct page.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 include/linux/mm_types.h | 14 --------------
 include/linux/pgtable.h  |  3 ---
 2 files changed, 17 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index fbbe4e93a9ba..434e54440686 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -141,20 +141,6 @@ struct page {
 		struct {	/* Tail pages of compound page */
 			unsigned long compound_head;	/* Bit zero is set */
 		};
-		struct {	/* Page table pages */
-			unsigned long _pt_pad_1;	/* compound_head */
-			pgtable_t pmd_huge_pte; /* protected by page->ptl */
-			unsigned long _pt_s390_gaddr;	/* mapping */
-			union {
-				struct mm_struct *pt_mm; /* x86 pgds only */
-				atomic_t pt_frag_refcount; /* powerpc */
-			};
-#if ALLOC_SPLIT_PTLOCKS
-			spinlock_t *ptl;
-#else
-			spinlock_t ptl;
-#endif
-		};
 		struct {	/* ZONE_DEVICE pages */
 			/** @pgmap: Points to the hosting device page map. */
 			struct dev_pagemap *pgmap;
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index e9bb5f18cade..daeacfe3930d 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1044,10 +1044,7 @@ struct ptdesc {
 TABLE_MATCH(flags, __page_flags);
 TABLE_MATCH(compound_head, pt_list);
 TABLE_MATCH(compound_head, _pt_pad_1);
-TABLE_MATCH(pmd_huge_pte, pmd_huge_pte);
 TABLE_MATCH(mapping, _pt_s390_gaddr);
-TABLE_MATCH(pt_mm, pt_mm);
-TABLE_MATCH(ptl, ptl);
 TABLE_MATCH(rcu_head, pt_rcu_head);
 #ifdef CONFIG_MEMCG
 TABLE_MATCH(memcg_data, pt_memcg_data);
-- 
2.40.1

[PATCH v6 18/33] pgalloc: Convert various functions to use ptdescs

[Vishal Moola (Oracle)]

As part of the conversions to replace pgtable constructor/destructors with
ptdesc equivalents, convert various page table functions to use ptdescs.

Some of the functions use the *get*page*() helper functions. Convert
these to use pagetable_alloc() and ptdesc_address() instead to help
standardize page tables further.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
---
 include/asm-generic/pgalloc.h | 88 +++++++++++++++++++++--------------
 1 file changed, 52 insertions(+), 36 deletions(-)

diff --git a/include/asm-generic/pgalloc.h b/include/asm-generic/pgalloc.h
index a7cf825befae..c75d4a753849 100644
--- a/include/asm-generic/pgalloc.h
+++ b/include/asm-generic/pgalloc.h
@@ -8,7 +8,7 @@
 #define GFP_PGTABLE_USER	(GFP_PGTABLE_KERNEL | __GFP_ACCOUNT)
 
 /**
- * __pte_alloc_one_kernel - allocate a page for PTE-level kernel page table
+ * __pte_alloc_one_kernel - allocate memory for a PTE-level kernel page table
  * @mm: the mm_struct of the current context
  *
  * This function is intended for architectures that need
@@ -18,12 +18,17 @@
  */
 static inline pte_t *__pte_alloc_one_kernel(struct mm_struct *mm)
 {
-	return (pte_t *)__get_free_page(GFP_PGTABLE_KERNEL);
+	struct ptdesc *ptdesc = pagetable_alloc(GFP_PGTABLE_KERNEL &
+			~__GFP_HIGHMEM, 0);
+
+	if (!ptdesc)
+		return NULL;
+	return ptdesc_address(ptdesc);
 }
 
 #ifndef __HAVE_ARCH_PTE_ALLOC_ONE_KERNEL
 /**
- * pte_alloc_one_kernel - allocate a page for PTE-level kernel page table
+ * pte_alloc_one_kernel - allocate memory for a PTE-level kernel page table
  * @mm: the mm_struct of the current context
  *
  * Return: pointer to the allocated memory or %NULL on error
@@ -35,40 +40,40 @@ static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
 #endif
 
 /**
- * pte_free_kernel - free PTE-level kernel page table page
+ * pte_free_kernel - free PTE-level kernel page table memory
  * @mm: the mm_struct of the current context
  * @pte: pointer to the memory containing the page table
  */
 static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 {
-	free_page((unsigned long)pte);
+	pagetable_free(virt_to_ptdesc(pte));
 }
 
 /**
- * __pte_alloc_one - allocate a page for PTE-level user page table
+ * __pte_alloc_one - allocate memory for a PTE-level user page table
  * @mm: the mm_struct of the current context
  * @gfp: GFP flags to use for the allocation
  *
- * Allocates a page and runs the pgtable_pte_page_ctor().
+ * Allocate memory for a page table and ptdesc and runs pagetable_pte_ctor().
  *
  * This function is intended for architectures that need
  * anything beyond simple page allocation or must have custom GFP flags.
  *
- * Return: `struct page` initialized as page table or %NULL on error
+ * Return: `struct page` referencing the ptdesc or %NULL on error
  */
 static inline pgtable_t __pte_alloc_one(struct mm_struct *mm, gfp_t gfp)
 {
-	struct page *pte;
+	struct ptdesc *ptdesc;
 
-	pte = alloc_page(gfp);
-	if (!pte)
+	ptdesc = pagetable_alloc(gfp, 0);
+	if (!ptdesc)
 		return NULL;
-	if (!pgtable_pte_page_ctor(pte)) {
-		__free_page(pte);
+	if (!pagetable_pte_ctor(ptdesc)) {
+		pagetable_free(ptdesc);
 		return NULL;
 	}
 
-	return pte;
+	return ptdesc_page(ptdesc);
 }
 
 #ifndef __HAVE_ARCH_PTE_ALLOC_ONE
@@ -76,9 +81,9 @@ static inline pgtable_t __pte_alloc_one(struct mm_struct *mm, gfp_t gfp)
  * pte_alloc_one - allocate a page for PTE-level user page table
  * @mm: the mm_struct of the current context
  *
- * Allocates a page and runs the pgtable_pte_page_ctor().
+ * Allocate memory for a page table and ptdesc and runs pagetable_pte_ctor().
  *
- * Return: `struct page` initialized as page table or %NULL on error
+ * Return: `struct page` referencing the ptdesc or %NULL on error
  */
 static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
 {
@@ -92,14 +97,16 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
  */
 
 /**
- * pte_free - free PTE-level user page table page
+ * pte_free - free PTE-level user page table memory
  * @mm: the mm_struct of the current context
- * @pte_page: the `struct page` representing the page table
+ * @pte_page: the `struct page` referencing the ptdesc
  */
 static inline void pte_free(struct mm_struct *mm, struct page *pte_page)
 {
-	pgtable_pte_page_dtor(pte_page);
-	__free_page(pte_page);
+	struct ptdesc *ptdesc = page_ptdesc(pte_page);
+
+	pagetable_pte_dtor(ptdesc);
+	pagetable_free(ptdesc);
 }
 
 
@@ -107,10 +114,11 @@ static inline void pte_free(struct mm_struct *mm, struct page *pte_page)
 
 #ifndef __HAVE_ARCH_PMD_ALLOC_ONE
 /**
- * pmd_alloc_one - allocate a page for PMD-level page table
+ * pmd_alloc_one - allocate memory for a PMD-level page table
  * @mm: the mm_struct of the current context
  *
- * Allocates a page and runs the pgtable_pmd_page_ctor().
+ * Allocate memory for a page table and ptdesc and runs pagetable_pmd_ctor().
+ *
  * Allocations use %GFP_PGTABLE_USER in user context and
  * %GFP_PGTABLE_KERNEL in kernel context.
  *
@@ -118,28 +126,30 @@ static inline void pte_free(struct mm_struct *mm, struct page *pte_page)
  */
 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
 {
-	struct page *page;
+	struct ptdesc *ptdesc;
 	gfp_t gfp = GFP_PGTABLE_USER;
 
 	if (mm == &init_mm)
 		gfp = GFP_PGTABLE_KERNEL;
-	page = alloc_page(gfp);
-	if (!page)
+	ptdesc = pagetable_alloc(gfp, 0);
+	if (!ptdesc)
 		return NULL;
-	if (!pgtable_pmd_page_ctor(page)) {
-		__free_page(page);
+	if (!pagetable_pmd_ctor(ptdesc)) {
+		pagetable_free(ptdesc);
 		return NULL;
 	}
-	return (pmd_t *)page_address(page);
+	return ptdesc_address(ptdesc);
 }
 #endif
 
 #ifndef __HAVE_ARCH_PMD_FREE
 static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
 {
+	struct ptdesc *ptdesc = virt_to_ptdesc(pmd);
+
 	BUG_ON((unsigned long)pmd & (PAGE_SIZE-1));
-	pgtable_pmd_page_dtor(virt_to_page(pmd));
-	free_page((unsigned long)pmd);
+	pagetable_pmd_dtor(ptdesc);
+	pagetable_free(ptdesc);
 }
 #endif
 
@@ -150,19 +160,25 @@ static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
 static inline pud_t *__pud_alloc_one(struct mm_struct *mm, unsigned long addr)
 {
 	gfp_t gfp = GFP_PGTABLE_USER;
+	struct ptdesc *ptdesc;
 
 	if (mm == &init_mm)
 		gfp = GFP_PGTABLE_KERNEL;
-	return (pud_t *)get_zeroed_page(gfp);
+	gfp &= ~__GFP_HIGHMEM;
+
+	ptdesc = pagetable_alloc(gfp, 0);
+	if (!ptdesc)
+		return NULL;
+	return ptdesc_address(ptdesc);
 }
 
 #ifndef __HAVE_ARCH_PUD_ALLOC_ONE
 /**
- * pud_alloc_one - allocate a page for PUD-level page table
+ * pud_alloc_one - allocate memory for a PUD-level page table
  * @mm: the mm_struct of the current context
  *
- * Allocates a page using %GFP_PGTABLE_USER for user context and
- * %GFP_PGTABLE_KERNEL for kernel context.
+ * Allocate memory for a page table using %GFP_PGTABLE_USER for user context
+ * and %GFP_PGTABLE_KERNEL for kernel context.
  *
  * Return: pointer to the allocated memory or %NULL on error
  */
@@ -175,7 +191,7 @@ static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
 static inline void __pud_free(struct mm_struct *mm, pud_t *pud)
 {
 	BUG_ON((unsigned long)pud & (PAGE_SIZE-1));
-	free_page((unsigned long)pud);
+	pagetable_free(virt_to_ptdesc(pud));
 }
 
 #ifndef __HAVE_ARCH_PUD_FREE
@@ -190,7 +206,7 @@ static inline void pud_free(struct mm_struct *mm, pud_t *pud)
 #ifndef __HAVE_ARCH_PGD_FREE
 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 {
-	free_page((unsigned long)pgd);
+	pagetable_free(virt_to_ptdesc(pgd));
 }
 #endif
 
-- 
2.40.1

[PATCH v6 19/33] arm: Convert various functions to use ptdescs

[Vishal Moola (Oracle)]

As part of the conversions to replace pgtable constructor/destructors with
ptdesc equivalents, convert various page table functions to use ptdescs.

late_alloc() also uses the __get_free_pages() helper function. Convert
this to use pagetable_alloc() and ptdesc_address() instead to help
standardize page tables further.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/arm/include/asm/tlb.h | 12 +++++++-----
 arch/arm/mm/mmu.c          |  7 ++++---
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/arch/arm/include/asm/tlb.h b/arch/arm/include/asm/tlb.h
index b8cbe03ad260..f40d06ad5d2a 100644
--- a/arch/arm/include/asm/tlb.h
+++ b/arch/arm/include/asm/tlb.h
@@ -39,7 +39,9 @@ static inline void __tlb_remove_table(void *_table)
 static inline void
 __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte, unsigned long addr)
 {
-	pgtable_pte_page_dtor(pte);
+	struct ptdesc *ptdesc = page_ptdesc(pte);
+
+	pagetable_pte_dtor(ptdesc);
 
 #ifndef CONFIG_ARM_LPAE
 	/*
@@ -50,17 +52,17 @@ __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte, unsigned long addr)
 	__tlb_adjust_range(tlb, addr - PAGE_SIZE, 2 * PAGE_SIZE);
 #endif
 
-	tlb_remove_table(tlb, pte);
+	tlb_remove_ptdesc(tlb, ptdesc);
 }
 
 static inline void
 __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp, unsigned long addr)
 {
 #ifdef CONFIG_ARM_LPAE
-	struct page *page = virt_to_page(pmdp);
+	struct ptdesc *ptdesc = virt_to_ptdesc(pmdp);
 
-	pgtable_pmd_page_dtor(page);
-	tlb_remove_table(tlb, page);
+	pagetable_pmd_dtor(ptdesc);
+	tlb_remove_ptdesc(tlb, ptdesc);
 #endif
 }
 
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 13fc4bb5f792..fdeaee30d167 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -737,11 +737,12 @@ static void __init *early_alloc(unsigned long sz)
 
 static void *__init late_alloc(unsigned long sz)
 {
-	void *ptr = (void *)__get_free_pages(GFP_PGTABLE_KERNEL, get_order(sz));
+	void *ptdesc = pagetable_alloc(GFP_PGTABLE_KERNEL & ~__GFP_HIGHMEM,
+			get_order(sz));
 
-	if (!ptr || !pgtable_pte_page_ctor(virt_to_page(ptr)))
+	if (!ptdesc || !pagetable_pte_ctor(ptdesc))
 		BUG();
-	return ptr;
+	return ptdesc_to_virt(ptdesc);
 }
 
 static pte_t * __init arm_pte_alloc(pmd_t *pmd, unsigned long addr,
-- 
2.40.1

[PATCH v6 20/33] arm64: Convert various functions to use ptdescs

[Vishal Moola (Oracle)]

As part of the conversions to replace pgtable constructor/destructors with
ptdesc equivalents, convert various page table functions to use ptdescs.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
---
 arch/arm64/include/asm/tlb.h | 14 ++++++++------
 arch/arm64/mm/mmu.c          |  7 ++++---
 2 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/include/asm/tlb.h b/arch/arm64/include/asm/tlb.h
index c995d1f4594f..2c29239d05c3 100644
--- a/arch/arm64/include/asm/tlb.h
+++ b/arch/arm64/include/asm/tlb.h
@@ -75,18 +75,20 @@ static inline void tlb_flush(struct mmu_gather *tlb)
 static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
 				  unsigned long addr)
 {
-	pgtable_pte_page_dtor(pte);
-	tlb_remove_table(tlb, pte);
+	struct ptdesc *ptdesc = page_ptdesc(pte);
+
+	pagetable_pte_dtor(ptdesc);
+	tlb_remove_ptdesc(tlb, ptdesc);
 }
 
 #if CONFIG_PGTABLE_LEVELS > 2
 static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp,
 				  unsigned long addr)
 {
-	struct page *page = virt_to_page(pmdp);
+	struct ptdesc *ptdesc = virt_to_ptdesc(pmdp);
 
-	pgtable_pmd_page_dtor(page);
-	tlb_remove_table(tlb, page);
+	pagetable_pmd_dtor(ptdesc);
+	tlb_remove_ptdesc(tlb, ptdesc);
 }
 #endif
 
@@ -94,7 +96,7 @@ static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp,
 static inline void __pud_free_tlb(struct mmu_gather *tlb, pud_t *pudp,
 				  unsigned long addr)
 {
-	tlb_remove_table(tlb, virt_to_page(pudp));
+	tlb_remove_ptdesc(tlb, virt_to_ptdesc(pudp));
 }
 #endif
 
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 95d360805f8a..47781bec6171 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -426,6 +426,7 @@ static phys_addr_t __pgd_pgtable_alloc(int shift)
 static phys_addr_t pgd_pgtable_alloc(int shift)
 {
 	phys_addr_t pa = __pgd_pgtable_alloc(shift);
+	struct ptdesc *ptdesc = page_ptdesc(phys_to_page(pa));
 
 	/*
 	 * Call proper page table ctor in case later we need to
@@ -433,12 +434,12 @@ static phys_addr_t pgd_pgtable_alloc(int shift)
 	 * this pre-allocated page table.
 	 *
 	 * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is
-	 * folded, and if so pgtable_pmd_page_ctor() becomes nop.
+	 * folded, and if so pagetable_pte_ctor() becomes nop.
 	 */
 	if (shift == PAGE_SHIFT)
-		BUG_ON(!pgtable_pte_page_ctor(phys_to_page(pa)));
+		BUG_ON(!pagetable_pte_ctor(ptdesc));
 	else if (shift == PMD_SHIFT)
-		BUG_ON(!pgtable_pmd_page_ctor(phys_to_page(pa)));
+		BUG_ON(!pagetable_pmd_ctor(ptdesc));
 
 	return pa;
 }
-- 
2.40.1

[PATCH v6 21/33] csky: Convert __pte_free_tlb() to use ptdescs

[Vishal Moola (Oracle)]

Part of the conversions to replace pgtable constructor/destructors with
ptdesc equivalents.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Guo Ren <guoren@kernel.org>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/csky/include/asm/pgalloc.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/csky/include/asm/pgalloc.h b/arch/csky/include/asm/pgalloc.h
index 7d57e5da0914..9c84c9012e53 100644
--- a/arch/csky/include/asm/pgalloc.h
+++ b/arch/csky/include/asm/pgalloc.h
@@ -63,8 +63,8 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 
 #define __pte_free_tlb(tlb, pte, address)		\
 do {							\
-	pgtable_pte_page_dtor(pte);			\
-	tlb_remove_page(tlb, pte);			\
+	pagetable_pte_dtor(page_ptdesc(pte));		\
+	tlb_remove_page_ptdesc(tlb, page_ptdesc(pte));	\
 } while (0)
 
 extern void pagetable_init(void);
-- 
2.40.1

[PATCH v6 22/33] hexagon: Convert __pte_free_tlb() to use ptdescs

[Vishal Moola (Oracle)]

Part of the conversions to replace pgtable constructor/destructors with
ptdesc equivalents.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/hexagon/include/asm/pgalloc.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/hexagon/include/asm/pgalloc.h b/arch/hexagon/include/asm/pgalloc.h
index f0c47e6a7427..55988625e6fb 100644
--- a/arch/hexagon/include/asm/pgalloc.h
+++ b/arch/hexagon/include/asm/pgalloc.h
@@ -87,10 +87,10 @@ static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
 		max_kernel_seg = pmdindex;
 }
 
-#define __pte_free_tlb(tlb, pte, addr)		\
-do {						\
-	pgtable_pte_page_dtor((pte));		\
-	tlb_remove_page((tlb), (pte));		\
+#define __pte_free_tlb(tlb, pte, addr)				\
+do {								\
+	pagetable_pte_dtor((page_ptdesc(pte)));			\
+	tlb_remove_page_ptdesc((tlb), (page_ptdesc(pte)));	\
 } while (0)
 
 #endif
-- 
2.40.1

[PATCH v6 23/33] loongarch: Convert various functions to use ptdescs

[Vishal Moola (Oracle)]

As part of the conversions to replace pgtable constructor/destructors with
ptdesc equivalents, convert various page table functions to use ptdescs.

Some of the functions use the *get*page*() helper functions. Convert
these to use pagetable_alloc() and ptdesc_address() instead to help
standardize page tables further.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/loongarch/include/asm/pgalloc.h | 27 +++++++++++++++------------
 arch/loongarch/mm/pgtable.c          |  7 ++++---
 2 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/arch/loongarch/include/asm/pgalloc.h b/arch/loongarch/include/asm/pgalloc.h
index af1d1e4a6965..23f5b1107246 100644
--- a/arch/loongarch/include/asm/pgalloc.h
+++ b/arch/loongarch/include/asm/pgalloc.h
@@ -45,9 +45,9 @@ extern void pagetable_init(void);
 extern pgd_t *pgd_alloc(struct mm_struct *mm);
 
 #define __pte_free_tlb(tlb, pte, address)			\
-do {							\
-	pgtable_pte_page_dtor(pte);			\
-	tlb_remove_page((tlb), pte);			\
+do {								\
+	pagetable_pte_dtor(page_ptdesc(pte));			\
+	tlb_remove_page_ptdesc((tlb), page_ptdesc(pte));	\
 } while (0)
 
 #ifndef __PAGETABLE_PMD_FOLDED
@@ -55,18 +55,18 @@ do {							\
 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 {
 	pmd_t *pmd;
-	struct page *pg;
+	struct ptdesc *ptdesc;
 
-	pg = alloc_page(GFP_KERNEL_ACCOUNT);
-	if (!pg)
+	ptdesc = pagetable_alloc(GFP_KERNEL_ACCOUNT, 0);
+	if (!ptdesc)
 		return NULL;
 
-	if (!pgtable_pmd_page_ctor(pg)) {
-		__free_page(pg);
+	if (!pagetable_pmd_ctor(ptdesc)) {
+		pagetable_free(ptdesc);
 		return NULL;
 	}
 
-	pmd = (pmd_t *)page_address(pg);
+	pmd = ptdesc_address(ptdesc);
 	pmd_init(pmd);
 	return pmd;
 }
@@ -80,10 +80,13 @@ static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long address)
 {
 	pud_t *pud;
+	struct ptdesc *ptdesc = pagetable_alloc(GFP_KERNEL & ~__GFP_HIGHMEM, 0);
 
-	pud = (pud_t *) __get_free_page(GFP_KERNEL);
-	if (pud)
-		pud_init(pud);
+	if (!ptdesc)
+		return NULL;
+	pud = ptdesc_address(ptdesc);
+
+	pud_init(pud);
 	return pud;
 }
 
diff --git a/arch/loongarch/mm/pgtable.c b/arch/loongarch/mm/pgtable.c
index 36a6dc0148ae..5bd102b51f7c 100644
--- a/arch/loongarch/mm/pgtable.c
+++ b/arch/loongarch/mm/pgtable.c
@@ -11,10 +11,11 @@
 
 pgd_t *pgd_alloc(struct mm_struct *mm)
 {
-	pgd_t *ret, *init;
+	pgd_t *init, *ret = NULL;
+	struct ptdesc *ptdesc = pagetable_alloc(GFP_KERNEL & ~__GFP_HIGHMEM, 0);
 
-	ret = (pgd_t *) __get_free_page(GFP_KERNEL);
-	if (ret) {
+	if (ptdesc) {
+		ret = (pgd_t *)ptdesc_address(ptdesc);
 		init = pgd_offset(&init_mm, 0UL);
 		pgd_init(ret);
 		memcpy(ret + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,
-- 
2.40.1

[PATCH v6 24/33] m68k: Convert various functions to use ptdescs

[Vishal Moola (Oracle)]

As part of the conversions to replace pgtable constructor/destructors with
ptdesc equivalents, convert various page table functions to use ptdescs.

Some of the functions use the *get*page*() helper functions. Convert
these to use pagetable_alloc() and ptdesc_address() instead to help
standardize page tables further.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
 arch/m68k/include/asm/mcf_pgalloc.h  | 47 ++++++++++++++--------------
 arch/m68k/include/asm/sun3_pgalloc.h |  8 ++---
 arch/m68k/mm/motorola.c              |  4 +--
 3 files changed, 30 insertions(+), 29 deletions(-)

diff --git a/arch/m68k/include/asm/mcf_pgalloc.h b/arch/m68k/include/asm/mcf_pgalloc.h
index 5c2c0a864524..302c5bf67179 100644
--- a/arch/m68k/include/asm/mcf_pgalloc.h
+++ b/arch/m68k/include/asm/mcf_pgalloc.h
@@ -5,22 +5,22 @@
 #include <asm/tlb.h>
 #include <asm/tlbflush.h>
 
-extern inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
+static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 {
-	free_page((unsigned long) pte);
+	pagetable_free(virt_to_ptdesc(pte));
 }
 
 extern const char bad_pmd_string[];
 
-extern inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
+static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
 {
-	unsigned long page = __get_free_page(GFP_DMA);
+	struct ptdesc *ptdesc = pagetable_alloc((GFP_DMA | __GFP_ZERO) &
+			~__GFP_HIGHMEM, 0);
 
-	if (!page)
+	if (!ptdesc)
 		return NULL;
 
-	memset((void *)page, 0, PAGE_SIZE);
-	return (pte_t *) (page);
+	return ptdesc_address(ptdesc);
 }
 
 extern inline pmd_t *pmd_alloc_kernel(pgd_t *pgd, unsigned long address)
@@ -35,36 +35,34 @@ extern inline pmd_t *pmd_alloc_kernel(pgd_t *pgd, unsigned long address)
 static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pgtable,
 				  unsigned long address)
 {
-	struct page *page = virt_to_page(pgtable);
+	struct ptdesc *ptdesc = virt_to_ptdesc(pgtable);
 
-	pgtable_pte_page_dtor(page);
-	__free_page(page);
+	pagetable_pte_dtor(ptdesc);
+	pagetable_free(ptdesc);
 }
 
 static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
 {
-	struct page *page = alloc_pages(GFP_DMA, 0);
+	struct ptdesc *ptdesc = pagetable_alloc(GFP_DMA | __GFP_ZERO, 0);
 	pte_t *pte;
 
-	if (!page)
+	if (!ptdesc)
 		return NULL;
-	if (!pgtable_pte_page_ctor(page)) {
-		__free_page(page);
+	if (!pagetable_pte_ctor(ptdesc)) {
+		pagetable_free(ptdesc);
 		return NULL;
 	}
 
-	pte = page_address(page);
-	clear_page(pte);
-
+	pte = ptdesc_address(ptdesc);
 	return pte;
 }
 
 static inline void pte_free(struct mm_struct *mm, pgtable_t pgtable)
 {
-	struct page *page = virt_to_page(pgtable);
+	struct ptdesc *ptdesc = virt_to_ptdesc(pgtable);
 
-	pgtable_pte_page_dtor(page);
-	__free_page(page);
+	pagetable_pte_dtor(ptdesc);
+	pagetable_free(ptdesc);
 }
 
 /*
@@ -75,16 +73,19 @@ static inline void pte_free(struct mm_struct *mm, pgtable_t pgtable)
 
 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 {
-	free_page((unsigned long) pgd);
+	pagetable_free(virt_to_ptdesc(pgd));
 }
 
 static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 {
 	pgd_t *new_pgd;
+	struct ptdesc *ptdesc = pagetable_alloc((GFP_DMA | __GFP_NOWARN) &
+			~__GFP_HIGHMEM, 0);
 
-	new_pgd = (pgd_t *)__get_free_page(GFP_DMA | __GFP_NOWARN);
-	if (!new_pgd)
+	if (!ptdesc)
 		return NULL;
+	new_pgd = ptdesc_address(ptdesc);
+
 	memcpy(new_pgd, swapper_pg_dir, PTRS_PER_PGD * sizeof(pgd_t));
 	memset(new_pgd, 0, PAGE_OFFSET >> PGDIR_SHIFT);
 	return new_pgd;
diff --git a/arch/m68k/include/asm/sun3_pgalloc.h b/arch/m68k/include/asm/sun3_pgalloc.h
index 198036aff519..ff48573db2c0 100644
--- a/arch/m68k/include/asm/sun3_pgalloc.h
+++ b/arch/m68k/include/asm/sun3_pgalloc.h
@@ -17,10 +17,10 @@
 
 extern const char bad_pmd_string[];
 
-#define __pte_free_tlb(tlb,pte,addr)			\
-do {							\
-	pgtable_pte_page_dtor(pte);			\
-	tlb_remove_page((tlb), pte);			\
+#define __pte_free_tlb(tlb, pte, addr)				\
+do {								\
+	pagetable_pte_dtor(page_ptdesc(pte));			\
+	tlb_remove_page_ptdesc((tlb), page_ptdesc(pte));	\
 } while (0)
 
 static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
diff --git a/arch/m68k/mm/motorola.c b/arch/m68k/mm/motorola.c
index c75984e2d86b..594575a0780c 100644
--- a/arch/m68k/mm/motorola.c
+++ b/arch/m68k/mm/motorola.c
@@ -161,7 +161,7 @@ void *get_pointer_table(int type)
 			 * m68k doesn't have SPLIT_PTE_PTLOCKS for not having
 			 * SMP.
 			 */
-			pgtable_pte_page_ctor(virt_to_page(page));
+			pagetable_pte_ctor(virt_to_ptdesc(page));
 		}
 
 		mmu_page_ctor(page);
@@ -201,7 +201,7 @@ int free_pointer_table(void *table, int type)
 		list_del(dp);
 		mmu_page_dtor((void *)page);
 		if (type == TABLE_PTE)
-			pgtable_pte_page_dtor(virt_to_page((void *)page));
+			pagetable_pte_dtor(virt_to_ptdesc((void *)page));
 		free_page (page);
 		return 1;
 	} else if (ptable_list[type].next != dp) {
-- 
2.40.1

[PATCH v6 25/33] mips: Convert various functions to use ptdescs

[Vishal Moola (Oracle)]

As part of the conversions to replace pgtable constructor/destructors with
ptdesc equivalents, convert various page table functions to use ptdescs.

Some of the functions use the *get*page*() helper functions. Convert
these to use pagetable_alloc() and ptdesc_address() instead to help
standardize page tables further.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/mips/include/asm/pgalloc.h | 32 ++++++++++++++++++--------------
 arch/mips/mm/pgtable.c          |  8 +++++---
 2 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/arch/mips/include/asm/pgalloc.h b/arch/mips/include/asm/pgalloc.h
index f72e737dda21..40e40a7eb94a 100644
--- a/arch/mips/include/asm/pgalloc.h
+++ b/arch/mips/include/asm/pgalloc.h
@@ -51,13 +51,13 @@ extern pgd_t *pgd_alloc(struct mm_struct *mm);
 
 static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 {
-	free_pages((unsigned long)pgd, PGD_TABLE_ORDER);
+	pagetable_free(virt_to_ptdesc(pgd));
 }
 
-#define __pte_free_tlb(tlb,pte,address)			\
-do {							\
-	pgtable_pte_page_dtor(pte);			\
-	tlb_remove_page((tlb), pte);			\
+#define __pte_free_tlb(tlb, pte, address)			\
+do {								\
+	pagetable_pte_dtor(page_ptdesc(pte));			\
+	tlb_remove_page_ptdesc((tlb), page_ptdesc(pte));	\
 } while (0)
 
 #ifndef __PAGETABLE_PMD_FOLDED
@@ -65,18 +65,18 @@ do {							\
 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 {
 	pmd_t *pmd;
-	struct page *pg;
+	struct ptdesc *ptdesc;
 
-	pg = alloc_pages(GFP_KERNEL_ACCOUNT, PMD_TABLE_ORDER);
-	if (!pg)
+	ptdesc = pagetable_alloc(GFP_KERNEL_ACCOUNT, PMD_TABLE_ORDER);
+	if (!ptdesc)
 		return NULL;
 
-	if (!pgtable_pmd_page_ctor(pg)) {
-		__free_pages(pg, PMD_TABLE_ORDER);
+	if (!pagetable_pmd_ctor(ptdesc)) {
+		pagetable_free(ptdesc);
 		return NULL;
 	}
 
-	pmd = (pmd_t *)page_address(pg);
+	pmd = ptdesc_address(ptdesc);
 	pmd_init(pmd);
 	return pmd;
 }
@@ -90,10 +90,14 @@ static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long address)
 {
 	pud_t *pud;
+	struct ptdesc *ptdesc = pagetable_alloc(GFP_KERNEL & ~__GFP_HIGHMEM,
+			PUD_TABLE_ORDER);
 
-	pud = (pud_t *) __get_free_pages(GFP_KERNEL, PUD_TABLE_ORDER);
-	if (pud)
-		pud_init(pud);
+	if (!ptdesc)
+		return NULL;
+	pud = ptdesc_address(ptdesc);
+
+	pud_init(pud);
 	return pud;
 }
 
diff --git a/arch/mips/mm/pgtable.c b/arch/mips/mm/pgtable.c
index b13314be5d0e..1506e458040d 100644
--- a/arch/mips/mm/pgtable.c
+++ b/arch/mips/mm/pgtable.c
@@ -10,10 +10,12 @@
 
 pgd_t *pgd_alloc(struct mm_struct *mm)
 {
-	pgd_t *ret, *init;
+	pgd_t *init, *ret = NULL;
+	struct ptdesc *ptdesc = pagetable_alloc(GFP_KERNEL & ~__GFP_HIGHMEM,
+			PGD_TABLE_ORDER);
 
-	ret = (pgd_t *) __get_free_pages(GFP_KERNEL, PGD_TABLE_ORDER);
-	if (ret) {
+	if (ptdesc) {
+		ret = ptdesc_address(ptdesc);
 		init = pgd_offset(&init_mm, 0UL);
 		pgd_init(ret);
 		memcpy(ret + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,
-- 
2.40.1

[PATCH v6 26/33] nios2: Convert __pte_free_tlb() to use ptdescs

[Vishal Moola (Oracle)]

Part of the conversions to replace pgtable constructor/destructors with
ptdesc equivalents.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
---
 arch/nios2/include/asm/pgalloc.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/nios2/include/asm/pgalloc.h b/arch/nios2/include/asm/pgalloc.h
index ecd1657bb2ce..ce6bb8e74271 100644
--- a/arch/nios2/include/asm/pgalloc.h
+++ b/arch/nios2/include/asm/pgalloc.h
@@ -28,10 +28,10 @@ static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
 
 extern pgd_t *pgd_alloc(struct mm_struct *mm);
 
-#define __pte_free_tlb(tlb, pte, addr)				\
-	do {							\
-		pgtable_pte_page_dtor(pte);			\
-		tlb_remove_page((tlb), (pte));			\
+#define __pte_free_tlb(tlb, pte, addr)					\
+	do {								\
+		pagetable_pte_dtor(page_ptdesc(pte));			\
+		tlb_remove_page_ptdesc((tlb), (page_ptdesc(pte)));	\
 	} while (0)
 
 #endif /* _ASM_NIOS2_PGALLOC_H */
-- 
2.40.1

[PATCH v6 27/33] openrisc: Convert __pte_free_tlb() to use ptdescs

[Vishal Moola (Oracle)]

Part of the conversions to replace pgtable constructor/destructors with
ptdesc equivalents.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/openrisc/include/asm/pgalloc.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/openrisc/include/asm/pgalloc.h b/arch/openrisc/include/asm/pgalloc.h
index b7b2b8d16fad..c6a73772a546 100644
--- a/arch/openrisc/include/asm/pgalloc.h
+++ b/arch/openrisc/include/asm/pgalloc.h
@@ -66,10 +66,10 @@ extern inline pgd_t *pgd_alloc(struct mm_struct *mm)
 
 extern pte_t *pte_alloc_one_kernel(struct mm_struct *mm);
 
-#define __pte_free_tlb(tlb, pte, addr)	\
-do {					\
-	pgtable_pte_page_dtor(pte);	\
-	tlb_remove_page((tlb), (pte));	\
+#define __pte_free_tlb(tlb, pte, addr)				\
+do {								\
+	pagetable_pte_dtor(page_ptdesc(pte));			\
+	tlb_remove_page_ptdesc((tlb), (page_ptdesc(pte)));	\
 } while (0)
 
 #endif
-- 
2.40.1

[PATCH v6 28/33] riscv: Convert alloc_{pmd, pte}_late() to use ptdescs

[Vishal Moola (Oracle)]

As part of the conversions to replace pgtable constructor/destructors with
ptdesc equivalents, convert various page table functions to use ptdescs.

Some of the functions use the *get*page*() helper functions. Convert
these to use pagetable_alloc() and ptdesc_address() instead to help
standardize page tables further.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/riscv/include/asm/pgalloc.h |  8 ++++----
 arch/riscv/mm/init.c             | 16 ++++++----------
 2 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/arch/riscv/include/asm/pgalloc.h b/arch/riscv/include/asm/pgalloc.h
index 59dc12b5b7e8..d169a4f41a2e 100644
--- a/arch/riscv/include/asm/pgalloc.h
+++ b/arch/riscv/include/asm/pgalloc.h
@@ -153,10 +153,10 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 
 #endif /* __PAGETABLE_PMD_FOLDED */
 
-#define __pte_free_tlb(tlb, pte, buf)   \
-do {                                    \
-	pgtable_pte_page_dtor(pte);     \
-	tlb_remove_page((tlb), pte);    \
+#define __pte_free_tlb(tlb, pte, buf)			\
+do {							\
+	pagetable_pte_dtor(page_ptdesc(pte));		\
+	tlb_remove_page_ptdesc((tlb), page_ptdesc(pte));\
 } while (0)
 #endif /* CONFIG_MMU */
 
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 4b95d8999120..efff9c752fcf 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -354,12 +354,10 @@ static inline phys_addr_t __init alloc_pte_fixmap(uintptr_t va)
 
 static phys_addr_t __init alloc_pte_late(uintptr_t va)
 {
-	unsigned long vaddr;
-
-	vaddr = __get_free_page(GFP_KERNEL);
-	BUG_ON(!vaddr || !pgtable_pte_page_ctor(virt_to_page((void *)vaddr)));
+	struct ptdesc *ptdesc = pagetable_alloc(GFP_KERNEL & ~__GFP_HIGHMEM, 0);
 
-	return __pa(vaddr);
+	BUG_ON(!ptdesc || !pagetable_pte_ctor(ptdesc));
+	return __pa((pte_t *)ptdesc_address(ptdesc));
 }
 
 static void __init create_pte_mapping(pte_t *ptep,
@@ -437,12 +435,10 @@ static phys_addr_t __init alloc_pmd_fixmap(uintptr_t va)
 
 static phys_addr_t __init alloc_pmd_late(uintptr_t va)
 {
-	unsigned long vaddr;
-
-	vaddr = __get_free_page(GFP_KERNEL);
-	BUG_ON(!vaddr || !pgtable_pmd_page_ctor(virt_to_page((void *)vaddr)));
+	struct ptdesc *ptdesc = pagetable_alloc(GFP_KERNEL & ~__GFP_HIGHMEM, 0);
 
-	return __pa(vaddr);
+	BUG_ON(!ptdesc || !pagetable_pmd_ctor(ptdesc));
+	return __pa((pmd_t *)ptdesc_address(ptdesc));
 }
 
 static void __init create_pmd_mapping(pmd_t *pmdp,
-- 
2.40.1

[PATCH v6 29/33] sh: Convert pte_free_tlb() to use ptdescs

[Vishal Moola (Oracle)]

Part of the conversions to replace pgtable constructor/destructors with
ptdesc equivalents. Also cleans up some spacing issues.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/sh/include/asm/pgalloc.h | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/sh/include/asm/pgalloc.h b/arch/sh/include/asm/pgalloc.h
index a9e98233c4d4..5d8577ab1591 100644
--- a/arch/sh/include/asm/pgalloc.h
+++ b/arch/sh/include/asm/pgalloc.h
@@ -2,6 +2,7 @@
 #ifndef __ASM_SH_PGALLOC_H
 #define __ASM_SH_PGALLOC_H
 
+#include <linux/mm.h>
 #include <asm/page.h>
 
 #define __HAVE_ARCH_PMD_ALLOC_ONE
@@ -31,10 +32,10 @@ static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
 	set_pmd(pmd, __pmd((unsigned long)page_address(pte)));
 }
 
-#define __pte_free_tlb(tlb,pte,addr)			\
-do {							\
-	pgtable_pte_page_dtor(pte);			\
-	tlb_remove_page((tlb), (pte));			\
+#define __pte_free_tlb(tlb, pte, addr)				\
+do {								\
+	pagetable_pte_dtor(page_ptdesc(pte));			\
+	tlb_remove_page_ptdesc((tlb), (page_ptdesc(pte)));	\
 } while (0)
 
 #endif /* __ASM_SH_PGALLOC_H */
-- 
2.40.1

[PATCH v6 30/33] sparc64: Convert various functions to use ptdescs

[Vishal Moola (Oracle)]

As part of the conversions to replace pgtable constructor/destructors with
ptdesc equivalents, convert various page table functions to use ptdescs.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/sparc/mm/init_64.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 04f9db0c3111..105915cd2eee 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -2893,14 +2893,15 @@ pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
 
 pgtable_t pte_alloc_one(struct mm_struct *mm)
 {
-	struct page *page = alloc_page(GFP_KERNEL | __GFP_ZERO);
-	if (!page)
+	struct ptdesc *ptdesc = pagetable_alloc(GFP_KERNEL | __GFP_ZERO, 0);
+
+	if (!ptdesc)
 		return NULL;
-	if (!pgtable_pte_page_ctor(page)) {
-		__free_page(page);
+	if (!pagetable_pte_ctor(ptdesc)) {
+		pagetable_free(ptdesc);
 		return NULL;
 	}
-	return (pte_t *) page_address(page);
+	return ptdesc_address(ptdesc);
 }
 
 void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
@@ -2910,10 +2911,10 @@ void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 
 static void __pte_free(pgtable_t pte)
 {
-	struct page *page = virt_to_page(pte);
+	struct ptdesc *ptdesc = virt_to_ptdesc(pte);
 
-	pgtable_pte_page_dtor(page);
-	__free_page(page);
+	pagetable_pte_dtor(ptdesc);
+	pagetable_free(ptdesc);
 }
 
 void pte_free(struct mm_struct *mm, pgtable_t pte)
-- 
2.40.1

[PATCH v6 31/33] sparc: Convert pgtable_pte_page_{ctor, dtor}() to ptdesc equivalents

[Vishal Moola (Oracle)]

Part of the conversions to replace pgtable pte constructor/destructors with
ptdesc equivalents.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/sparc/mm/srmmu.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/sparc/mm/srmmu.c b/arch/sparc/mm/srmmu.c
index 13f027afc875..8393faa3e596 100644
--- a/arch/sparc/mm/srmmu.c
+++ b/arch/sparc/mm/srmmu.c
@@ -355,7 +355,8 @@ pgtable_t pte_alloc_one(struct mm_struct *mm)
 		return NULL;
 	page = pfn_to_page(__nocache_pa((unsigned long)ptep) >> PAGE_SHIFT);
 	spin_lock(&mm->page_table_lock);
-	if (page_ref_inc_return(page) == 2 && !pgtable_pte_page_ctor(page)) {
+	if (page_ref_inc_return(page) == 2 &&
+			!pagetable_pte_ctor(page_ptdesc(page))) {
 		page_ref_dec(page);
 		ptep = NULL;
 	}
@@ -371,7 +372,7 @@ void pte_free(struct mm_struct *mm, pgtable_t ptep)
 	page = pfn_to_page(__nocache_pa((unsigned long)ptep) >> PAGE_SHIFT);
 	spin_lock(&mm->page_table_lock);
 	if (page_ref_dec_return(page) == 1)
-		pgtable_pte_page_dtor(page);
+		pagetable_pte_dtor(page_ptdesc(page));
 	spin_unlock(&mm->page_table_lock);
 
 	srmmu_free_nocache(ptep, SRMMU_PTE_TABLE_SIZE);
-- 
2.40.1

[PATCH v6 32/33] um: Convert {pmd, pte}_free_tlb() to use ptdescs

[Vishal Moola (Oracle)]

Part of the conversions to replace pgtable constructor/destructors with
ptdesc equivalents. Also cleans up some spacing issues.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/um/include/asm/pgalloc.h | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/arch/um/include/asm/pgalloc.h b/arch/um/include/asm/pgalloc.h
index 8ec7cd46dd96..de5e31c64793 100644
--- a/arch/um/include/asm/pgalloc.h
+++ b/arch/um/include/asm/pgalloc.h
@@ -25,19 +25,19 @@
  */
 extern pgd_t *pgd_alloc(struct mm_struct *);
 
-#define __pte_free_tlb(tlb,pte, address)		\
-do {							\
-	pgtable_pte_page_dtor(pte);			\
-	tlb_remove_page((tlb),(pte));			\
+#define __pte_free_tlb(tlb, pte, address)			\
+do {								\
+	pagetable_pte_dtor(page_ptdesc(pte));			\
+	tlb_remove_page_ptdesc((tlb), (page_ptdesc(pte)));	\
 } while (0)
 
 #ifdef CONFIG_3_LEVEL_PGTABLES
 
-#define __pmd_free_tlb(tlb, pmd, address)		\
-do {							\
-	pgtable_pmd_page_dtor(virt_to_page(pmd));	\
-	tlb_remove_page((tlb),virt_to_page(pmd));	\
-} while (0)						\
+#define __pmd_free_tlb(tlb, pmd, address)			\
+do {								\
+	pagetable_pmd_dtor(virt_to_ptdesc(pmd));			\
+	tlb_remove_page_ptdesc((tlb), virt_to_ptdesc(pmd));	\
+} while (0)
 
 #endif
 
-- 
2.40.1

[PATCH v6 33/33] mm: Remove pgtable_{pmd, pte}_page_{ctor, dtor}() wrappers

[Vishal Moola (Oracle)]

These functions are no longer necessary. Remove them and cleanup
Documentation referencing them.

Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 Documentation/mm/split_page_table_lock.rst    | 12 +++++------
 .../zh_CN/mm/split_page_table_lock.rst        | 14 ++++++-------
 include/linux/mm.h                            | 20 -------------------
 3 files changed, 13 insertions(+), 33 deletions(-)

diff --git a/Documentation/mm/split_page_table_lock.rst b/Documentation/mm/split_page_table_lock.rst
index a834fad9de12..e4f6972eb6c0 100644
--- a/Documentation/mm/split_page_table_lock.rst
+++ b/Documentation/mm/split_page_table_lock.rst
@@ -58,7 +58,7 @@ Support of split page table lock by an architecture
 ===================================================
 
 There's no need in special enabling of PTE split page table lock: everything
-required is done by pgtable_pte_page_ctor() and pgtable_pte_page_dtor(), which
+required is done by pagetable_pte_ctor() and pagetable_pte_dtor(), which
 must be called on PTE table allocation / freeing.
 
 Make sure the architecture doesn't use slab allocator for page table
@@ -68,8 +68,8 @@ This field shares storage with page->ptl.
 PMD split lock only makes sense if you have more than two page table
 levels.
 
-PMD split lock enabling requires pgtable_pmd_page_ctor() call on PMD table
-allocation and pgtable_pmd_page_dtor() on freeing.
+PMD split lock enabling requires pagetable_pmd_ctor() call on PMD table
+allocation and pagetable_pmd_dtor() on freeing.
 
 Allocation usually happens in pmd_alloc_one(), freeing in pmd_free() and
 pmd_free_tlb(), but make sure you cover all PMD table allocation / freeing
@@ -77,7 +77,7 @@ paths: i.e X86_PAE preallocate few PMDs on pgd_alloc().
 
 With everything in place you can set CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK.
 
-NOTE: pgtable_pte_page_ctor() and pgtable_pmd_page_ctor() can fail -- it must
+NOTE: pagetable_pte_ctor() and pagetable_pmd_ctor() can fail -- it must
 be handled properly.
 
 page->ptl
@@ -97,7 +97,7 @@ trick:
    split lock with enabled DEBUG_SPINLOCK or DEBUG_LOCK_ALLOC, but costs
    one more cache line for indirect access;
 
-The spinlock_t allocated in pgtable_pte_page_ctor() for PTE table and in
-pgtable_pmd_page_ctor() for PMD table.
+The spinlock_t allocated in pagetable_pte_ctor() for PTE table and in
+pagetable_pmd_ctor() for PMD table.
 
 Please, never access page->ptl directly -- use appropriate helper.
diff --git a/Documentation/translations/zh_CN/mm/split_page_table_lock.rst b/Documentation/translations/zh_CN/mm/split_page_table_lock.rst
index 4fb7aa666037..a2c288670a24 100644
--- a/Documentation/translations/zh_CN/mm/split_page_table_lock.rst
+++ b/Documentation/translations/zh_CN/mm/split_page_table_lock.rst
@@ -56,16 +56,16 @@ Hugetlb特定的辅助函数:
 架构对分页表锁的支持
 ====================
 
-没有必要特别启用PTE分页表锁：所有需要的东西都由pgtable_pte_page_ctor()
-和pgtable_pte_page_dtor()完成，它们必须在PTE表分配/释放时被调用。
+没有必要特别启用PTE分页表锁：所有需要的东西都由pagetable_pte_ctor()
+和pagetable_pte_dtor()完成，它们必须在PTE表分配/释放时被调用。
 
 确保架构不使用slab分配器来分配页表：slab使用page->slab_cache来分配其页
 面。这个区域与page->ptl共享存储。
 
 PMD分页锁只有在你有两个以上的页表级别时才有意义。
 
-启用PMD分页锁需要在PMD表分配时调用pgtable_pmd_page_ctor()，在释放时调
-用pgtable_pmd_page_dtor()。
+启用PMD分页锁需要在PMD表分配时调用pagetable_pmd_ctor()，在释放时调
+用pagetable_pmd_dtor()。
 
 分配通常发生在pmd_alloc_one()中，释放发生在pmd_free()和pmd_free_tlb()
 中，但要确保覆盖所有的PMD表分配/释放路径：即X86_PAE在pgd_alloc()中预先
@@ -73,7 +73,7 @@ PMD分页锁只有在你有两个以上的页表级别时才有意义。
 
 一切就绪后，你可以设置CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK。
 
-注意：pgtable_pte_page_ctor()和pgtable_pmd_page_ctor()可能失败--必
+注意：pagetable_pte_ctor()和pagetable_pmd_ctor()可能失败--必
 须正确处理。
 
 page->ptl
@@ -90,7 +90,7 @@ page->ptl用于访问分割页表锁，其中'page'是包含该表的页面struc
    的指针并动态分配它。这允许在启用DEBUG_SPINLOCK或DEBUG_LOCK_ALLOC的
    情况下使用分页锁，但由于间接访问而多花了一个缓存行。
 
-PTE表的spinlock_t分配在pgtable_pte_page_ctor()中，PMD表的spinlock_t
-分配在pgtable_pmd_page_ctor()中。
+PTE表的spinlock_t分配在pagetable_pte_ctor()中，PMD表的spinlock_t
+分配在pagetable_pmd_ctor()中。
 
 请不要直接访问page->ptl - -使用适当的辅助函数。
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0e4d5f6d10e5..dc0f19f35424 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2873,11 +2873,6 @@ static inline bool pagetable_pte_ctor(struct ptdesc *ptdesc)
 	return true;
 }
 
-static inline bool pgtable_pte_page_ctor(struct page *page)
-{
-	return pagetable_pte_ctor(page_ptdesc(page));
-}
-
 static inline void pagetable_pte_dtor(struct ptdesc *ptdesc)
 {
 	struct folio *folio = ptdesc_folio(ptdesc);
@@ -2887,11 +2882,6 @@ static inline void pagetable_pte_dtor(struct ptdesc *ptdesc)
 	lruvec_stat_sub_folio(folio, NR_PAGETABLE);
 }
 
-static inline void pgtable_pte_page_dtor(struct page *page)
-{
-	pagetable_pte_dtor(page_ptdesc(page));
-}
-
 pte_t *__pte_offset_map(pmd_t *pmd, unsigned long addr, pmd_t *pmdvalp);
 static inline pte_t *pte_offset_map(pmd_t *pmd, unsigned long addr)
 {
@@ -2993,11 +2983,6 @@ static inline bool pagetable_pmd_ctor(struct ptdesc *ptdesc)
 	return true;
 }
 
-static inline bool pgtable_pmd_page_ctor(struct page *page)
-{
-	return pagetable_pmd_ctor(page_ptdesc(page));
-}
-
 static inline void pagetable_pmd_dtor(struct ptdesc *ptdesc)
 {
 	struct folio *folio = ptdesc_folio(ptdesc);
@@ -3007,11 +2992,6 @@ static inline void pagetable_pmd_dtor(struct ptdesc *ptdesc)
 	lruvec_stat_sub_folio(folio, NR_PAGETABLE);
 }
 
-static inline void pgtable_pmd_page_dtor(struct page *page)
-{
-	pagetable_pmd_dtor(page_ptdesc(page));
-}
-
 /*
  * No scalability reason to split PUD locks yet, but follow the same pattern
  * as the PMD locks to make it easier if we decide to.  The VM should not be
-- 
2.40.1

Re: [PATCH v6 00/33] Split ptdesc from struct page

[Hugh Dickins]

On Mon, 26 Jun 2023, Vishal Moola (Oracle) wrote:

> The MM subsystem is trying to shrink struct page. This patchset
> introduces a memory descriptor for page table tracking - struct ptdesc.
...
>  39 files changed, 686 insertions(+), 455 deletions(-)

I don't see the point of this patchset: to me it is just obfuscation of
the present-day tight relationship between page table and struct page.

Matthew already explained:

> The intent is to get ptdescs to be dynamically allocated at some point
> in the ~2-3 years out future when we have finished the folio project ...

So in a kindly mood, I'd say that this patchset is ahead of its time.
But I can certainly adapt to it, if everyone else sees some point to it.

Hugh

Re: [PATCH v6 00/33] Split ptdesc from struct page

[David Hildenbrand]

On 27.06.23 06:44, Hugh Dickins wrote:
> On Mon, 26 Jun 2023, Vishal Moola (Oracle) wrote:
> 
>> The MM subsystem is trying to shrink struct page. This patchset
>> introduces a memory descriptor for page table tracking - struct ptdesc.
> ...
>>   39 files changed, 686 insertions(+), 455 deletions(-)
> 
> I don't see the point of this patchset: to me it is just obfuscation of
> the present-day tight relationship between page table and struct page.
> 
> Matthew already explained:
> 
>> The intent is to get ptdescs to be dynamically allocated at some point
>> in the ~2-3 years out future when we have finished the folio project ...
> 
> So in a kindly mood, I'd say that this patchset is ahead of its time.
> But I can certainly adapt to it, if everyone else sees some point to it.

I share your thoughts, that code churn which will help eventually in the 
far, far future (not wanting to sound too pessimistic, but it's not 
going to be there tomorrow ;) ).

However, if it's just the same as the other conversions we already did 
(e.g., struct slab), then I guess there is no reason to stop now -- the 
obfuscation already happened.

... or is there a difference regarding this conversion and the previous 
ones?

-- 
Cheers,

David / dhildenb

Re: [PATCH v6 00/33] Split ptdesc from struct page

[Matthew Wilcox]

On Mon, Jun 26, 2023 at 09:44:08PM -0700, Hugh Dickins wrote:
> On Mon, 26 Jun 2023, Vishal Moola (Oracle) wrote:
> 
> > The MM subsystem is trying to shrink struct page. This patchset
> > introduces a memory descriptor for page table tracking - struct ptdesc.
> ...
> >  39 files changed, 686 insertions(+), 455 deletions(-)
> 
> I don't see the point of this patchset: to me it is just obfuscation of
> the present-day tight relationship between page table and struct page.
> 
> Matthew already explained:
> 
> > The intent is to get ptdescs to be dynamically allocated at some point
> > in the ~2-3 years out future when we have finished the folio project ...
> 
> So in a kindly mood, I'd say that this patchset is ahead of its time.
> But I can certainly adapt to it, if everyone else sees some point to it.

If you think this patchset is ahead of its time, we can certainly put
it on hold.  We're certainly prepared to redo it to be merged after your
current patch series.

I think you can see the advantage of the destination, so I don't think
you're against that.  Are you opposed to the sequencing of the work to
get us there?  I'd be happy to discuss another way to do it.

For example, we could dynamically allocate ptdescs right now.  We'd get
the benefit of having an arbitrary amount of space in the ptdesc,
although not the benefit of a smaller memmap until everything else is
also dynamically allocated.

Re: [PATCH v6 03/33] pgtable: Create struct ptdesc

[Peter Xu]

On Mon, Jun 26, 2023 at 08:14:01PM -0700, Vishal Moola (Oracle) wrote:
> Currently, page table information is stored within struct page. As part
> of simplifying struct page, create struct ptdesc for page table
> information.
> 
> Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
> ---
>  include/linux/pgtable.h | 68 +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 68 insertions(+)
> 
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index 5063b482e34f..d46cb709ce08 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -987,6 +987,74 @@ static inline void ptep_modify_prot_commit(struct vm_area_struct *vma,
>  #endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
>  #endif /* CONFIG_MMU */
>  
> +
> +/**
> + * struct ptdesc -    Memory descriptor for page tables.
> + * @__page_flags:     Same as page flags. Unused for page tables.
> + * @pt_rcu_head:      For freeing page table pages.
> + * @pt_list:          List of used page tables. Used for s390 and x86.
> + * @_pt_pad_1:        Padding that aliases with page's compound head.
> + * @pmd_huge_pte:     Protected by ptdesc->ptl, used for THPs.
> + * @_pt_s390_gaddr:   Aliases with page's mapping. Used for s390 gmap only.

Should some arch-specific bits (and a few others) always under some
#ifdefs, so it shouldn't appear on other archs?

> + * @pt_mm:            Used for x86 pgds.
> + * @pt_frag_refcount: For fragmented page table tracking. Powerpc and s390 only.
> + * @ptl:              Lock for the page table.
> + * @__page_type:      Same as page->page_type. Unused for page tables.
> + * @_refcount:        Same as page refcount. Used for s390 page tables.
> + * @pt_memcg_data:    Memcg data. Tracked for page tables here.
> + *
> + * This struct overlays struct page for now. Do not modify without a good
> + * understanding of the issues.
> + */
> +struct ptdesc {
> +	unsigned long __page_flags;
> +
> +	union {
> +		struct rcu_head pt_rcu_head;
> +		struct list_head pt_list;
> +		struct {
> +			unsigned long _pt_pad_1;
> +			pgtable_t pmd_huge_pte;
> +		};
> +	};
> +	unsigned long _pt_s390_gaddr;
> +
> +	union {
> +		struct mm_struct *pt_mm;
> +		atomic_t pt_frag_refcount;
> +	};
> +
> +	union {
> +		unsigned long _pt_pad_2;
> +#if ALLOC_SPLIT_PTLOCKS
> +		spinlock_t *ptl;
> +#else
> +		spinlock_t ptl;
> +#endif
> +	};
> +	unsigned int __page_type;
> +	atomic_t _refcount;
> +#ifdef CONFIG_MEMCG
> +	unsigned long pt_memcg_data;
> +#endif
> +};

-- 
Peter Xu

Re: [PATCH v6 03/33] pgtable: Create struct ptdesc

[Vishal Moola]

On Tue, Jun 27, 2023 at 9:07 AM Peter Xu <peterx@redhat.com> wrote:
>
> On Mon, Jun 26, 2023 at 08:14:01PM -0700, Vishal Moola (Oracle) wrote:
> > Currently, page table information is stored within struct page. As part
> > of simplifying struct page, create struct ptdesc for page table
> > information.
> >
> > Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
> > Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
> > ---
> >  include/linux/pgtable.h | 68 +++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 68 insertions(+)
> >
> > diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> > index 5063b482e34f..d46cb709ce08 100644
> > --- a/include/linux/pgtable.h
> > +++ b/include/linux/pgtable.h
> > @@ -987,6 +987,74 @@ static inline void ptep_modify_prot_commit(struct vm_area_struct *vma,
> >  #endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */
> >  #endif /* CONFIG_MMU */
> >
> > +
> > +/**
> > + * struct ptdesc -    Memory descriptor for page tables.
> > + * @__page_flags:     Same as page flags. Unused for page tables.
> > + * @pt_rcu_head:      For freeing page table pages.
> > + * @pt_list:          List of used page tables. Used for s390 and x86.
> > + * @_pt_pad_1:        Padding that aliases with page's compound head.
> > + * @pmd_huge_pte:     Protected by ptdesc->ptl, used for THPs.
> > + * @_pt_s390_gaddr:   Aliases with page's mapping. Used for s390 gmap only.
>
> Should some arch-specific bits (and a few others) always under some
> #ifdefs, so it shouldn't appear on other archs?

Right now this struct completely overlays struct page, so the padding as
well as any arch-specific fields have to stay. Whenever we get ptdescs
independent of struct page we can cleanup any unnecessary fields, as
well as omit unnecessary fields from unrelated architectures.

Re: [PATCH v6 00/33] Split ptdesc from struct page

[Hugh Dickins]

On Tue, 27 Jun 2023, David Hildenbrand wrote:
> On 27.06.23 06:44, Hugh Dickins wrote:
> > On Mon, 26 Jun 2023, Vishal Moola (Oracle) wrote:
> > 
> >> The MM subsystem is trying to shrink struct page. This patchset
> >> introduces a memory descriptor for page table tracking - struct ptdesc.
> > ...
> >>   39 files changed, 686 insertions(+), 455 deletions(-)
> > 
> > I don't see the point of this patchset: to me it is just obfuscation of
> > the present-day tight relationship between page table and struct page.
> > 
> > Matthew already explained:
> > 
> >> The intent is to get ptdescs to be dynamically allocated at some point
> >> in the ~2-3 years out future when we have finished the folio project ...
> > 
> > So in a kindly mood, I'd say that this patchset is ahead of its time.
> > But I can certainly adapt to it, if everyone else sees some point to it.
> 
> I share your thoughts, that code churn which will help eventually in the far,
> far future (not wanting to sound too pessimistic, but it's not going to be
> there tomorrow ;) ).
> 
> However, if it's just the same as the other conversions we already did (e.g.,
> struct slab), then I guess there is no reason to stop now -- the obfuscation
> already happened.
> 
> ... or is there a difference regarding this conversion and the previous ones?

I was aware of the struct slab thing, didn't see much point there myself
either; but it was welcomed by Vlastimil, and barely affected outside of
slab allocators, so I had no reason to object.

You think that if a little unnecessary churn (a *lot* of churn if you
include folios, which did save some repeated calls to compound_head())
has already occurred, that's a good precedent for allowing more and more?
My opinion happens to differ on that.

Hugh

Re: [PATCH v6 00/33] Split ptdesc from struct page

[Hugh Dickins]

On Tue, 27 Jun 2023, Matthew Wilcox wrote:
> On Mon, Jun 26, 2023 at 09:44:08PM -0700, Hugh Dickins wrote:
> > On Mon, 26 Jun 2023, Vishal Moola (Oracle) wrote:
> > 
> > > The MM subsystem is trying to shrink struct page. This patchset
> > > introduces a memory descriptor for page table tracking - struct ptdesc.
> > ...
> > >  39 files changed, 686 insertions(+), 455 deletions(-)
> > 
> > I don't see the point of this patchset: to me it is just obfuscation of
> > the present-day tight relationship between page table and struct page.
> > 
> > Matthew already explained:
> > 
> > > The intent is to get ptdescs to be dynamically allocated at some point
> > > in the ~2-3 years out future when we have finished the folio project ...
> > 
> > So in a kindly mood, I'd say that this patchset is ahead of its time.
> > But I can certainly adapt to it, if everyone else sees some point to it.
> 
> If you think this patchset is ahead of its time, we can certainly put
> it on hold.  We're certainly prepared to redo it to be merged after your
> current patch series.

Thank you, but I can adapt.  That was not my point:
I'm claiming this patchset is ~2-3 years ahead of its time.

> 
> I think you can see the advantage of the destination, so I don't think
> you're against that.

Maybe - I have some scepticism, but I'll be happy for that to be dissolved.

> Are you opposed to the sequencing of the work to
> get us there?  I'd be happy to discuss another way to do it.

Yes, I'm opposed to churn for no benefit.

> 
> For example, we could dynamically allocate ptdescs right now.  We'd get
> the benefit of having an arbitrary amount of space in the ptdesc,
> although not the benefit of a smaller memmap until everything else is
> also dynamically allocated.

That sounded much better, at first: churn serving good purpose.  But now
I suspect you're offering to dynamically allocate a ptdesc, in addition
to the struct page of the page table(s) itself, which will be wasted:
more memory consumption to no advantage.  If that's so, no thanks.

Hugh

Re: [PATCH v6 00/33] Split ptdesc from struct page

[David Hildenbrand]

On 27.06.23 22:13, Hugh Dickins wrote:
> On Tue, 27 Jun 2023, David Hildenbrand wrote:
>> On 27.06.23 06:44, Hugh Dickins wrote:
>>> On Mon, 26 Jun 2023, Vishal Moola (Oracle) wrote:
>>>
>>>> The MM subsystem is trying to shrink struct page. This patchset
>>>> introduces a memory descriptor for page table tracking - struct ptdesc.
>>> ...
>>>>    39 files changed, 686 insertions(+), 455 deletions(-)
>>>
>>> I don't see the point of this patchset: to me it is just obfuscation of
>>> the present-day tight relationship between page table and struct page.
>>>
>>> Matthew already explained:
>>>
>>>> The intent is to get ptdescs to be dynamically allocated at some point
>>>> in the ~2-3 years out future when we have finished the folio project ...
>>>
>>> So in a kindly mood, I'd say that this patchset is ahead of its time.
>>> But I can certainly adapt to it, if everyone else sees some point to it.
>>
>> I share your thoughts, that code churn which will help eventually in the far,
>> far future (not wanting to sound too pessimistic, but it's not going to be
>> there tomorrow ;) ).
>>
>> However, if it's just the same as the other conversions we already did (e.g.,
>> struct slab), then I guess there is no reason to stop now -- the obfuscation
>> already happened.
>>
>> ... or is there a difference regarding this conversion and the previous ones?
> 
> I was aware of the struct slab thing, didn't see much point there myself
> either; but it was welcomed by Vlastimil, and barely affected outside of
> slab allocators, so I had no reason to object.
> 
> You think that if a little unnecessary churn (a *lot* of churn if you
> include folios, which did save some repeated calls to compound_head())
> has already occurred, that's a good precedent for allowing more and more?

Well, if you phrase it like that ... no, I'm not in favor of unnecessary 
churn at all. Yes, folios were/are a lot of churn (IMHO not unnecessary, 
though).

I'm not a friend of these "overlays"; it all only really makes sense to 
me once we actually allocate the descriptors dynamically. Maybe some of 
the existing/ongoing conversions were different (that's why I was asking 
for the difference, as you said the "struct slab" thing was well received).

If they are primarily only unnecessary churn for now (and unclear 
when/how it will become useful), I share your opinion.

-- 
Cheers,

David / dhildenb

Re: [PATCH v6 00/33] Split ptdesc from struct page

[Matthew Wilcox]

On Wed, Jun 28, 2023 at 09:41:18AM +0200, David Hildenbrand wrote:
> I'm not a friend of these "overlays"; it all only really makes sense to me
> once we actually allocate the descriptors dynamically. Maybe some of the
> existing/ongoing conversions were different (that's why I was asking for the
> difference, as you said the "struct slab" thing was well received).
> 
> If they are primarily only unnecessary churn for now (and unclear when/how
> it will become useful), I share your opinion.

One of the reasons for doing these conversions "early" is that it helps
people who work on this code know what fields they can actually use in
their memory descriptor.  We have a _lot_ of historical baggage with
people just using random bits in struct page for their own purposes
without necessarily considering the effects on the rest of the system.

By creating specific types for each user of struct page, we can see
what's actually going on.  Before the ptdesc conversion started, I could
not have told you which bits in struct page were used by the s390 code.
I knew they were playing some fun games with the refcount (it's even
documented in the s390 code!) but I didn't know they were using ...
whetever it is; page->private to point to the kvm private data?

So maybe it is harder for MM developers right now to see what fields in
memdesc A overlap with which fields in memdesc B.  That _ought_ not to
be a concern!  We document which fields are available in each memdesc,
and have various assertions to trip when people make things not line up
any more.  There can still be problems, of course; we haven't set the
assertions quite tightly enough in some cases.

People are going to keep adding crap to struct page, and they're going
to keep misusing the crap that's in struct page.  That has to stop.