linux-mm.kvack.org archive mirror
 help / color / mirror / Atom feed
* [PATCH v7 00/19] The new cgroup slab memory controller
@ 2020-06-23  1:58 Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 01/19] mm: memcg: factor out memcg- and lruvec-level changes out of __mod_lruvec_state() Roman Gushchin
                   ` (19 more replies)
  0 siblings, 20 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

This is v7 of the slab cgroup controller rework.

The patchset moves the accounting from the page level to the object
level. It allows to share slab pages between memory cgroups.
This leads to a significant win in the slab utilization (up to 45%)
and the corresponding drop in the total kernel memory footprint.
The reduced number of unmovable slab pages should also have a positive
effect on the memory fragmentation.

The patchset makes the slab accounting code simpler: there is no more
need in the complicated dynamic creation and destruction of per-cgroup
slab caches, all memory cgroups use a global set of shared slab caches.
The lifetime of slab caches is not more connected to the lifetime
of memory cgroups.

The more precise accounting does require more CPU, however in practice
the difference seems to be negligible. We've been using the new slab
controller in Facebook production for several months with different
workloads and haven't seen any noticeable regressions. What we've seen
were memory savings in order of 1 GB per host (it varied heavily depending
on the actual workload, size of RAM, number of CPUs, memory pressure, etc).

The third version of the patchset added yet another step towards
the simplification of the code: sharing of slab caches between
accounted and non-accounted allocations. It comes with significant
upsides (most noticeable, a complete elimination of dynamic slab caches
creation) but not without some regression risks, so this change sits
on top of the patchset and is not completely merged in. So in the unlikely
event of a noticeable performance regression it can be reverted separately.

The slab memory accounting works in exactly the same way for SLAB and SLUB.
With both allocators the new controller shows significant memory savings,
with SLUB the difference is bigger. On my 16-core desktop machine running
Fedora 32 the size of the slab memory measured after the start of the system
was lower by 58% and 38% with SLUB and SLAB correspondingly.

v7:
  1) rebased on top of Vlastimil's slub improvements, by Andrew
  2) page->obj_cgroups is allocated from the same node, by Shakeel
  3) perf optimization in get_obj_cgroup_from_current(), by Shakeel
  4) added synchronization around allocation of page->obj_cgroups,
     by Shakeel
  5) fixed kmemleak false positives, by Qian Cai
  6) fixed a compiler warning on clang, by Nathan
  7) other minor fixes

v6:
  1) rebased on top of the mm tree
  2) removed a redundant check from cache_from_obj(), suggested by Vlastimil

v5:
  1) fixed a build error, spotted by Vlastimil
  2) added a comment about memcg->nr_charged_bytes, asked by Johannes
  3) added missed acks and reviews

v4:
  1) rebased on top of the mm tree, some fixes here and there
  2) merged obj_to_index() with slab_index(), suggested by Vlastimil
  3) changed objects_per_slab() to a better objects_per_slab_page(),
     suggested by Vlastimil
  4) other minor fixes and changes

v3:
  1) added a patch that switches to a global single set of kmem_caches
  2) kmem API clean up dropped, because if has been already merged
  3) byte-sized slab vmstat API over page-sized global counters and
     bytes-sized memcg/lruvec counters
  3) obj_cgroup refcounting simplifications and other minor fixes
  4) other minor changes

v2:
  1) implemented re-layering and renaming suggested by Johannes,
     added his patch to the set. Thanks!
  2) fixed the issue discovered by Bharata B Rao. Thanks!
  3) added kmem API clean up part
  4) added slab/memcg follow-up clean up part
  5) fixed a couple of issues discovered by internal testing on FB fleet.
  6) added kselftests
  7) included metadata into the charge calculation
  8) refreshed commit logs, regrouped patches, rebased onto mm tree, etc

v1:
  1) fixed a bug in zoneinfo_show_print()
  2) added some comments to the subpage charging API, a minor fix
  3) separated memory.kmem.slabinfo deprecation into a separate patch,
     provided a drgn-based replacement
  4) rebased on top of the current mm tree

RFC:
  https://lwn.net/Articles/798605/


Johannes Weiner (1):
  mm: memcontrol: decouple reference counting from page accounting

Roman Gushchin (18):
  mm: memcg: factor out memcg- and lruvec-level changes out of
    __mod_lruvec_state()
  mm: memcg: prepare for byte-sized vmstat items
  mm: memcg: convert vmstat slab counters to bytes
  mm: slub: implement SLUB version of obj_to_index()
  mm: memcg/slab: obj_cgroup API
  mm: memcg/slab: allocate obj_cgroups for non-root slab pages
  mm: memcg/slab: save obj_cgroup for non-root slab objects
  mm: memcg/slab: charge individual slab objects instead of pages
  mm: memcg/slab: deprecate memory.kmem.slabinfo
  mm: memcg/slab: move memcg_kmem_bypass() to memcontrol.h
  mm: memcg/slab: use a single set of kmem_caches for all accounted
    allocations
  mm: memcg/slab: simplify memcg cache creation
  mm: memcg/slab: remove memcg_kmem_get_cache()
  mm: memcg/slab: deprecate slab_root_caches
  mm: memcg/slab: remove redundant check in memcg_accumulate_slabinfo()
  mm: memcg/slab: use a single set of kmem_caches for all allocations
  kselftests: cgroup: add kernel memory accounting tests
  tools/cgroup: add memcg_slabinfo.py tool

 drivers/base/node.c                        |   6 +-
 fs/proc/meminfo.c                          |   4 +-
 include/linux/memcontrol.h                 |  85 ++-
 include/linux/mm_types.h                   |   5 +-
 include/linux/mmzone.h                     |  24 +-
 include/linux/slab.h                       |   5 -
 include/linux/slab_def.h                   |   9 +-
 include/linux/slub_def.h                   |  31 +-
 include/linux/vmstat.h                     |  14 +-
 kernel/power/snapshot.c                    |   2 +-
 mm/memcontrol.c                            | 610 +++++++++++--------
 mm/oom_kill.c                              |   2 +-
 mm/page_alloc.c                            |   8 +-
 mm/slab.c                                  |  70 +--
 mm/slab.h                                  | 370 +++++-------
 mm/slab_common.c                           | 643 +--------------------
 mm/slob.c                                  |  12 +-
 mm/slub.c                                  | 229 +-------
 mm/vmscan.c                                |   3 +-
 mm/vmstat.c                                |  30 +-
 mm/workingset.c                            |   6 +-
 tools/cgroup/memcg_slabinfo.py             | 226 ++++++++
 tools/testing/selftests/cgroup/.gitignore  |   1 +
 tools/testing/selftests/cgroup/Makefile    |   2 +
 tools/testing/selftests/cgroup/test_kmem.c | 382 ++++++++++++
 25 files changed, 1380 insertions(+), 1399 deletions(-)
 create mode 100644 tools/cgroup/memcg_slabinfo.py
 create mode 100644 tools/testing/selftests/cgroup/test_kmem.c

-- 
2.26.2



^ permalink raw reply	[flat|nested] 25+ messages in thread

* [PATCH v7 01/19] mm: memcg: factor out memcg- and lruvec-level changes out of __mod_lruvec_state()
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 02/19] mm: memcg: prepare for byte-sized vmstat items Roman Gushchin
                   ` (18 subsequent siblings)
  19 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

To convert memcg and lruvec slab counters to bytes there must be a way to
change these counters without touching node counters.  Factor out
__mod_memcg_lruvec_state() out of __mod_lruvec_state().

Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 include/linux/memcontrol.h | 17 +++++++++++++++
 mm/memcontrol.c            | 43 +++++++++++++++++++++-----------------
 2 files changed, 41 insertions(+), 19 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index e77197a62809..b250f8197710 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -679,11 +679,23 @@ static inline unsigned long lruvec_page_state_local(struct lruvec *lruvec,
 	return x;
 }
 
+void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
+			      int val);
 void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
 			int val);
 void __mod_lruvec_slab_state(void *p, enum node_stat_item idx, int val);
 void mod_memcg_obj_state(void *p, int idx, int val);
 
+static inline void mod_memcg_lruvec_state(struct lruvec *lruvec,
+					  enum node_stat_item idx, int val)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__mod_memcg_lruvec_state(lruvec, idx, val);
+	local_irq_restore(flags);
+}
+
 static inline void mod_lruvec_state(struct lruvec *lruvec,
 				    enum node_stat_item idx, int val)
 {
@@ -1057,6 +1069,11 @@ static inline unsigned long lruvec_page_state_local(struct lruvec *lruvec,
 	return node_page_state(lruvec_pgdat(lruvec), idx);
 }
 
+static inline void __mod_memcg_lruvec_state(struct lruvec *lruvec,
+					    enum node_stat_item idx, int val)
+{
+}
+
 static inline void __mod_lruvec_state(struct lruvec *lruvec,
 				      enum node_stat_item idx, int val)
 {
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 19622328e4b5..13ab84c7e4ac 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -713,30 +713,13 @@ parent_nodeinfo(struct mem_cgroup_per_node *pn, int nid)
 	return mem_cgroup_nodeinfo(parent, nid);
 }
 
-/**
- * __mod_lruvec_state - update lruvec memory statistics
- * @lruvec: the lruvec
- * @idx: the stat item
- * @val: delta to add to the counter, can be negative
- *
- * The lruvec is the intersection of the NUMA node and a cgroup. This
- * function updates the all three counters that are affected by a
- * change of state at this level: per-node, per-cgroup, per-lruvec.
- */
-void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
-			int val)
+void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
+			      int val)
 {
-	pg_data_t *pgdat = lruvec_pgdat(lruvec);
 	struct mem_cgroup_per_node *pn;
 	struct mem_cgroup *memcg;
 	long x;
 
-	/* Update node */
-	__mod_node_page_state(pgdat, idx, val);
-
-	if (mem_cgroup_disabled())
-		return;
-
 	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
 	memcg = pn->memcg;
 
@@ -748,6 +731,7 @@ void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
 
 	x = val + __this_cpu_read(pn->lruvec_stat_cpu->count[idx]);
 	if (unlikely(abs(x) > MEMCG_CHARGE_BATCH)) {
+		pg_data_t *pgdat = lruvec_pgdat(lruvec);
 		struct mem_cgroup_per_node *pi;
 
 		for (pi = pn; pi; pi = parent_nodeinfo(pi, pgdat->node_id))
@@ -757,6 +741,27 @@ void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
 	__this_cpu_write(pn->lruvec_stat_cpu->count[idx], x);
 }
 
+/**
+ * __mod_lruvec_state - update lruvec memory statistics
+ * @lruvec: the lruvec
+ * @idx: the stat item
+ * @val: delta to add to the counter, can be negative
+ *
+ * The lruvec is the intersection of the NUMA node and a cgroup. This
+ * function updates the all three counters that are affected by a
+ * change of state at this level: per-node, per-cgroup, per-lruvec.
+ */
+void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
+			int val)
+{
+	/* Update node */
+	__mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
+
+	/* Update memcg and lruvec */
+	if (!mem_cgroup_disabled())
+		__mod_memcg_lruvec_state(lruvec, idx, val);
+}
+
 void __mod_lruvec_slab_state(void *p, enum node_stat_item idx, int val)
 {
 	pg_data_t *pgdat = page_pgdat(virt_to_page(p));
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 02/19] mm: memcg: prepare for byte-sized vmstat items
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 01/19] mm: memcg: factor out memcg- and lruvec-level changes out of __mod_lruvec_state() Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 03/19] mm: memcg: convert vmstat slab counters to bytes Roman Gushchin
                   ` (17 subsequent siblings)
  19 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

To implement per-object slab memory accounting, we need to convert slab
vmstat counters to bytes.  Actually, out of 4 levels of counters: global,
per-node, per-memcg and per-lruvec only two last levels will require
byte-sized counters.  It's because global and per-node counters will be
counting the number of slab pages, and per-memcg and per-lruvec will be
counting the amount of memory taken by charged slab objects.

Converting all vmstat counters to bytes or even all slab counters to bytes
would introduce an additional overhead.  So instead let's store global and
per-node counters in pages, and memcg and lruvec counters in bytes.

To make the API clean all access helpers (both on the read and write
sides) are dealing with bytes.

To avoid back-and-forth conversions a new flavor of read-side helpers is
introduced, which always returns values in pages: node_page_state_pages()
and global_node_page_state_pages().

Actually new helpers are just reading raw values.  Old helpers are simple
wrappers, which will complain on an attempt to read byte value, because at
the moment no one actually needs bytes.

Thanks to Johannes Weiner for the idea of having the byte-sized API on top
of the page-sized internal storage.

Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 drivers/base/node.c    |  2 +-
 include/linux/mmzone.h | 10 ++++++++++
 include/linux/vmstat.h | 14 +++++++++++++-
 mm/memcontrol.c        | 14 ++++++++++----
 mm/vmstat.c            | 30 ++++++++++++++++++++++++++----
 5 files changed, 60 insertions(+), 10 deletions(-)

diff --git a/drivers/base/node.c b/drivers/base/node.c
index 5b02f69769e8..e21e31359297 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -513,7 +513,7 @@ static ssize_t node_read_vmstat(struct device *dev,
 
 	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
 		n += sprintf(buf+n, "%s %lu\n", node_stat_name(i),
-			     node_page_state(pgdat, i));
+			     node_page_state_pages(pgdat, i));
 
 	return n;
 }
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index f6f884970511..f16306e15b98 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -206,6 +206,16 @@ enum node_stat_item {
 	NR_VM_NODE_STAT_ITEMS
 };
 
+/*
+ * Returns true if the value is measured in bytes (most vmstat values are
+ * measured in pages). This defines the API part, the internal representation
+ * might be different.
+ */
+static __always_inline bool vmstat_item_in_bytes(int idx)
+{
+	return false;
+}
+
 /*
  * We do arithmetic on the LRU lists in various places in the code,
  * so it is important to keep the active lists LRU_ACTIVE higher in
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index aa961088c551..91220ace31da 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -8,6 +8,7 @@
 #include <linux/vm_event_item.h>
 #include <linux/atomic.h>
 #include <linux/static_key.h>
+#include <linux/mmdebug.h>
 
 extern int sysctl_stat_interval;
 
@@ -192,7 +193,8 @@ static inline unsigned long global_zone_page_state(enum zone_stat_item item)
 	return x;
 }
 
-static inline unsigned long global_node_page_state(enum node_stat_item item)
+static inline
+unsigned long global_node_page_state_pages(enum node_stat_item item)
 {
 	long x = atomic_long_read(&vm_node_stat[item]);
 #ifdef CONFIG_SMP
@@ -202,6 +204,13 @@ static inline unsigned long global_node_page_state(enum node_stat_item item)
 	return x;
 }
 
+static inline unsigned long global_node_page_state(enum node_stat_item item)
+{
+	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
+
+	return global_node_page_state_pages(item);
+}
+
 static inline unsigned long zone_page_state(struct zone *zone,
 					enum zone_stat_item item)
 {
@@ -242,9 +251,12 @@ extern unsigned long sum_zone_node_page_state(int node,
 extern unsigned long sum_zone_numa_state(int node, enum numa_stat_item item);
 extern unsigned long node_page_state(struct pglist_data *pgdat,
 						enum node_stat_item item);
+extern unsigned long node_page_state_pages(struct pglist_data *pgdat,
+					   enum node_stat_item item);
 #else
 #define sum_zone_node_page_state(node, item) global_zone_page_state(item)
 #define node_page_state(node, item) global_node_page_state(item)
+#define node_page_state_pages(node, item) global_node_page_state_pages(item)
 #endif /* CONFIG_NUMA */
 
 #ifdef CONFIG_SMP
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 13ab84c7e4ac..246f9c70118c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -681,13 +681,16 @@ mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
  */
 void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val)
 {
-	long x;
+	long x, threshold = MEMCG_CHARGE_BATCH;
 
 	if (mem_cgroup_disabled())
 		return;
 
+	if (vmstat_item_in_bytes(idx))
+		threshold <<= PAGE_SHIFT;
+
 	x = val + __this_cpu_read(memcg->vmstats_percpu->stat[idx]);
-	if (unlikely(abs(x) > MEMCG_CHARGE_BATCH)) {
+	if (unlikely(abs(x) > threshold)) {
 		struct mem_cgroup *mi;
 
 		/*
@@ -718,7 +721,7 @@ void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
 {
 	struct mem_cgroup_per_node *pn;
 	struct mem_cgroup *memcg;
-	long x;
+	long x, threshold = MEMCG_CHARGE_BATCH;
 
 	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
 	memcg = pn->memcg;
@@ -729,8 +732,11 @@ void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
 	/* Update lruvec */
 	__this_cpu_add(pn->lruvec_stat_local->count[idx], val);
 
+	if (vmstat_item_in_bytes(idx))
+		threshold <<= PAGE_SHIFT;
+
 	x = val + __this_cpu_read(pn->lruvec_stat_cpu->count[idx]);
-	if (unlikely(abs(x) > MEMCG_CHARGE_BATCH)) {
+	if (unlikely(abs(x) > threshold)) {
 		pg_data_t *pgdat = lruvec_pgdat(lruvec);
 		struct mem_cgroup_per_node *pi;
 
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 3fb23a21f6dd..b171a76bfe83 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -341,6 +341,11 @@ void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
 	long x;
 	long t;
 
+	if (vmstat_item_in_bytes(item)) {
+		VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
+		delta >>= PAGE_SHIFT;
+	}
+
 	x = delta + __this_cpu_read(*p);
 
 	t = __this_cpu_read(pcp->stat_threshold);
@@ -398,6 +403,8 @@ void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 	s8 __percpu *p = pcp->vm_node_stat_diff + item;
 	s8 v, t;
 
+	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
+
 	v = __this_cpu_inc_return(*p);
 	t = __this_cpu_read(pcp->stat_threshold);
 	if (unlikely(v > t)) {
@@ -442,6 +449,8 @@ void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 	s8 __percpu *p = pcp->vm_node_stat_diff + item;
 	s8 v, t;
 
+	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
+
 	v = __this_cpu_dec_return(*p);
 	t = __this_cpu_read(pcp->stat_threshold);
 	if (unlikely(v < - t)) {
@@ -541,6 +550,11 @@ static inline void mod_node_state(struct pglist_data *pgdat,
 	s8 __percpu *p = pcp->vm_node_stat_diff + item;
 	long o, n, t, z;
 
+	if (vmstat_item_in_bytes(item)) {
+		VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
+		delta >>= PAGE_SHIFT;
+	}
+
 	do {
 		z = 0;  /* overflow to node counters */
 
@@ -989,8 +1003,8 @@ unsigned long sum_zone_numa_state(int node,
 /*
  * Determine the per node value of a stat item.
  */
-unsigned long node_page_state(struct pglist_data *pgdat,
-				enum node_stat_item item)
+unsigned long node_page_state_pages(struct pglist_data *pgdat,
+				    enum node_stat_item item)
 {
 	long x = atomic_long_read(&pgdat->vm_stat[item]);
 #ifdef CONFIG_SMP
@@ -999,6 +1013,14 @@ unsigned long node_page_state(struct pglist_data *pgdat,
 #endif
 	return x;
 }
+
+unsigned long node_page_state(struct pglist_data *pgdat,
+			      enum node_stat_item item)
+{
+	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
+
+	return node_page_state_pages(pgdat, item);
+}
 #endif
 
 #ifdef CONFIG_COMPACTION
@@ -1577,7 +1599,7 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
 		seq_printf(m, "\n  per-node stats");
 		for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
 			seq_printf(m, "\n      %-12s %lu", node_stat_name(i),
-				   node_page_state(pgdat, i));
+				   node_page_state_pages(pgdat, i));
 		}
 	}
 	seq_printf(m,
@@ -1698,7 +1720,7 @@ static void *vmstat_start(struct seq_file *m, loff_t *pos)
 #endif
 
 	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
-		v[i] = global_node_page_state(i);
+		v[i] = global_node_page_state_pages(i);
 	v += NR_VM_NODE_STAT_ITEMS;
 
 	global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 03/19] mm: memcg: convert vmstat slab counters to bytes
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 01/19] mm: memcg: factor out memcg- and lruvec-level changes out of __mod_lruvec_state() Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 02/19] mm: memcg: prepare for byte-sized vmstat items Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 04/19] mm: slub: implement SLUB version of obj_to_index() Roman Gushchin
                   ` (16 subsequent siblings)
  19 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

In order to prepare for per-object slab memory accounting, convert
NR_SLAB_RECLAIMABLE and NR_SLAB_UNRECLAIMABLE vmstat items to bytes.

To make it obvious, rename them to NR_SLAB_RECLAIMABLE_B and
NR_SLAB_UNRECLAIMABLE_B (similar to NR_KERNEL_STACK_KB).

Internally global and per-node counters are stored in pages, however memcg
and lruvec counters are stored in bytes.  This scheme may look weird, but
only for now.  As soon as slab pages will be shared between multiple
cgroups, global and node counters will reflect the total number of slab
pages.  However memcg and lruvec counters will be used for per-memcg slab
memory tracking, which will take separate kernel objects in the account.
Keeping global and node counters in pages helps to avoid additional
overhead.

The size of slab memory shouldn't exceed 4Gb on 32-bit machines, so it
will fit into atomic_long_t we use for vmstats.

Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 drivers/base/node.c     |  4 ++--
 fs/proc/meminfo.c       |  4 ++--
 include/linux/mmzone.h  | 16 +++++++++++++---
 kernel/power/snapshot.c |  2 +-
 mm/memcontrol.c         | 11 ++++-------
 mm/oom_kill.c           |  2 +-
 mm/page_alloc.c         |  8 ++++----
 mm/slab.h               | 15 ++++++++-------
 mm/slab_common.c        |  4 ++--
 mm/slob.c               | 12 ++++++------
 mm/slub.c               |  8 ++++----
 mm/vmscan.c             |  3 ++-
 mm/workingset.c         |  6 ++++--
 13 files changed, 53 insertions(+), 42 deletions(-)

diff --git a/drivers/base/node.c b/drivers/base/node.c
index e21e31359297..0cf13e31603c 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -368,8 +368,8 @@ static ssize_t node_read_meminfo(struct device *dev,
 	unsigned long sreclaimable, sunreclaimable;
 
 	si_meminfo_node(&i, nid);
-	sreclaimable = node_page_state(pgdat, NR_SLAB_RECLAIMABLE);
-	sunreclaimable = node_page_state(pgdat, NR_SLAB_UNRECLAIMABLE);
+	sreclaimable = node_page_state_pages(pgdat, NR_SLAB_RECLAIMABLE_B);
+	sunreclaimable = node_page_state_pages(pgdat, NR_SLAB_UNRECLAIMABLE_B);
 	n = sprintf(buf,
 		       "Node %d MemTotal:       %8lu kB\n"
 		       "Node %d MemFree:        %8lu kB\n"
diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
index e9a6841fc25b..38ea95fd919a 100644
--- a/fs/proc/meminfo.c
+++ b/fs/proc/meminfo.c
@@ -52,8 +52,8 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
 		pages[lru] = global_node_page_state(NR_LRU_BASE + lru);
 
 	available = si_mem_available();
-	sreclaimable = global_node_page_state(NR_SLAB_RECLAIMABLE);
-	sunreclaim = global_node_page_state(NR_SLAB_UNRECLAIMABLE);
+	sreclaimable = global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B);
+	sunreclaim = global_node_page_state_pages(NR_SLAB_UNRECLAIMABLE_B);
 
 	show_val_kb(m, "MemTotal:       ", i.totalram);
 	show_val_kb(m, "MemFree:        ", i.freeram);
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index f16306e15b98..b79100edd228 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -174,8 +174,8 @@ enum node_stat_item {
 	NR_INACTIVE_FILE,	/*  "     "     "   "       "         */
 	NR_ACTIVE_FILE,		/*  "     "     "   "       "         */
 	NR_UNEVICTABLE,		/*  "     "     "   "       "         */
-	NR_SLAB_RECLAIMABLE,
-	NR_SLAB_UNRECLAIMABLE,
+	NR_SLAB_RECLAIMABLE_B,
+	NR_SLAB_UNRECLAIMABLE_B,
 	NR_ISOLATED_ANON,	/* Temporary isolated pages from anon lru */
 	NR_ISOLATED_FILE,	/* Temporary isolated pages from file lru */
 	WORKINGSET_NODES,
@@ -213,7 +213,17 @@ enum node_stat_item {
  */
 static __always_inline bool vmstat_item_in_bytes(int idx)
 {
-	return false;
+	/*
+	 * Global and per-node slab counters track slab pages.
+	 * It's expected that changes are multiples of PAGE_SIZE.
+	 * Internally values are stored in pages.
+	 *
+	 * Per-memcg and per-lruvec counters track memory, consumed
+	 * by individual slab objects. These counters are actually
+	 * byte-precise.
+	 */
+	return (idx == NR_SLAB_RECLAIMABLE_B ||
+		idx == NR_SLAB_UNRECLAIMABLE_B);
 }
 
 /*
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 881128b9351e..eefc907e5324 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -1663,7 +1663,7 @@ static unsigned long minimum_image_size(unsigned long saveable)
 {
 	unsigned long size;
 
-	size = global_node_page_state(NR_SLAB_RECLAIMABLE)
+	size = global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B)
 		+ global_node_page_state(NR_ACTIVE_ANON)
 		+ global_node_page_state(NR_INACTIVE_ANON)
 		+ global_node_page_state(NR_ACTIVE_FILE)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 246f9c70118c..a6216f7369b2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1391,9 +1391,8 @@ static char *memory_stat_format(struct mem_cgroup *memcg)
 		       (u64)memcg_page_state(memcg, MEMCG_KERNEL_STACK_KB) *
 		       1024);
 	seq_buf_printf(&s, "slab %llu\n",
-		       (u64)(memcg_page_state(memcg, NR_SLAB_RECLAIMABLE) +
-			     memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE)) *
-		       PAGE_SIZE);
+		       (u64)(memcg_page_state(memcg, NR_SLAB_RECLAIMABLE_B) +
+			     memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE_B)));
 	seq_buf_printf(&s, "sock %llu\n",
 		       (u64)memcg_page_state(memcg, MEMCG_SOCK) *
 		       PAGE_SIZE);
@@ -1423,11 +1422,9 @@ static char *memory_stat_format(struct mem_cgroup *memcg)
 			       PAGE_SIZE);
 
 	seq_buf_printf(&s, "slab_reclaimable %llu\n",
-		       (u64)memcg_page_state(memcg, NR_SLAB_RECLAIMABLE) *
-		       PAGE_SIZE);
+		       (u64)memcg_page_state(memcg, NR_SLAB_RECLAIMABLE_B));
 	seq_buf_printf(&s, "slab_unreclaimable %llu\n",
-		       (u64)memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE) *
-		       PAGE_SIZE);
+		       (u64)memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE_B));
 
 	/* Accumulated memory events */
 
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 6e94962893ee..d30ce75f23fb 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -184,7 +184,7 @@ static bool is_dump_unreclaim_slabs(void)
 		 global_node_page_state(NR_ISOLATED_FILE) +
 		 global_node_page_state(NR_UNEVICTABLE);
 
-	return (global_node_page_state(NR_SLAB_UNRECLAIMABLE) > nr_lru);
+	return (global_node_page_state_pages(NR_SLAB_UNRECLAIMABLE_B) > nr_lru);
 }
 
 /**
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 48eb0f1410d4..2304929c6a84 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5220,8 +5220,8 @@ long si_mem_available(void)
 	 * items that are in use, and cannot be freed. Cap this estimate at the
 	 * low watermark.
 	 */
-	reclaimable = global_node_page_state(NR_SLAB_RECLAIMABLE) +
-			global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE);
+	reclaimable = global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B) +
+		global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE);
 	available += reclaimable - min(reclaimable / 2, wmark_low);
 
 	if (available < 0)
@@ -5364,8 +5364,8 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
 		global_node_page_state(NR_UNEVICTABLE),
 		global_node_page_state(NR_FILE_DIRTY),
 		global_node_page_state(NR_WRITEBACK),
-		global_node_page_state(NR_SLAB_RECLAIMABLE),
-		global_node_page_state(NR_SLAB_UNRECLAIMABLE),
+		global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B),
+		global_node_page_state_pages(NR_SLAB_UNRECLAIMABLE_B),
 		global_node_page_state(NR_FILE_MAPPED),
 		global_node_page_state(NR_SHMEM),
 		global_zone_page_state(NR_PAGETABLE),
diff --git a/mm/slab.h b/mm/slab.h
index 136dead286b0..cc6afddd5632 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -272,7 +272,7 @@ int __kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
 static inline int cache_vmstat_idx(struct kmem_cache *s)
 {
 	return (s->flags & SLAB_RECLAIM_ACCOUNT) ?
-		NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE;
+		NR_SLAB_RECLAIMABLE_B : NR_SLAB_UNRECLAIMABLE_B;
 }
 
 #ifdef CONFIG_SLUB_DEBUG
@@ -389,7 +389,7 @@ static __always_inline int memcg_charge_slab(struct page *page,
 
 	if (unlikely(!memcg || mem_cgroup_is_root(memcg))) {
 		mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
-				    nr_pages);
+				    nr_pages << PAGE_SHIFT);
 		percpu_ref_get_many(&s->memcg_params.refcnt, nr_pages);
 		return 0;
 	}
@@ -399,7 +399,7 @@ static __always_inline int memcg_charge_slab(struct page *page,
 		goto out;
 
 	lruvec = mem_cgroup_lruvec(memcg, page_pgdat(page));
-	mod_lruvec_state(lruvec, cache_vmstat_idx(s), nr_pages);
+	mod_lruvec_state(lruvec, cache_vmstat_idx(s), nr_pages << PAGE_SHIFT);
 
 	/* transer try_charge() page references to kmem_cache */
 	percpu_ref_get_many(&s->memcg_params.refcnt, nr_pages);
@@ -424,11 +424,12 @@ static __always_inline void memcg_uncharge_slab(struct page *page, int order,
 	memcg = READ_ONCE(s->memcg_params.memcg);
 	if (likely(!mem_cgroup_is_root(memcg))) {
 		lruvec = mem_cgroup_lruvec(memcg, page_pgdat(page));
-		mod_lruvec_state(lruvec, cache_vmstat_idx(s), -nr_pages);
+		mod_lruvec_state(lruvec, cache_vmstat_idx(s),
+				 -(nr_pages << PAGE_SHIFT));
 		memcg_kmem_uncharge(memcg, nr_pages);
 	} else {
 		mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
-				    -nr_pages);
+				    -(nr_pages << PAGE_SHIFT));
 	}
 	rcu_read_unlock();
 
@@ -512,7 +513,7 @@ static __always_inline int charge_slab_page(struct page *page,
 {
 	if (is_root_cache(s)) {
 		mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
-				    1 << order);
+				    PAGE_SIZE << order);
 		return 0;
 	}
 
@@ -524,7 +525,7 @@ static __always_inline void uncharge_slab_page(struct page *page, int order,
 {
 	if (is_root_cache(s)) {
 		mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
-				    -(1 << order));
+				    -(PAGE_SIZE << order));
 		return;
 	}
 
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 5c2c11e59f0a..4fb76b45ce23 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1325,8 +1325,8 @@ void *kmalloc_order(size_t size, gfp_t flags, unsigned int order)
 	page = alloc_pages(flags, order);
 	if (likely(page)) {
 		ret = page_address(page);
-		mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE,
-				    1 << order);
+		mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE_B,
+				    PAGE_SIZE << order);
 	}
 	ret = kasan_kmalloc_large(ret, size, flags);
 	/* As ret might get tagged, call kmemleak hook after KASAN. */
diff --git a/mm/slob.c b/mm/slob.c
index ac2aecfbc7a8..7cc9805c8091 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -202,8 +202,8 @@ static void *slob_new_pages(gfp_t gfp, int order, int node)
 	if (!page)
 		return NULL;
 
-	mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE,
-			    1 << order);
+	mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE_B,
+			    PAGE_SIZE << order);
 	return page_address(page);
 }
 
@@ -214,8 +214,8 @@ static void slob_free_pages(void *b, int order)
 	if (current->reclaim_state)
 		current->reclaim_state->reclaimed_slab += 1 << order;
 
-	mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE,
-			    -(1 << order));
+	mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE_B,
+			    -(PAGE_SIZE << order));
 	__free_pages(sp, order);
 }
 
@@ -552,8 +552,8 @@ void kfree(const void *block)
 		slob_free(m, *m + align);
 	} else {
 		unsigned int order = compound_order(sp);
-		mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE,
-				    -(1 << order));
+		mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE_B,
+				    -(PAGE_SIZE << order));
 		__free_pages(sp, order);
 
 	}
diff --git a/mm/slub.c b/mm/slub.c
index 767738306171..c79d33cbe815 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3995,8 +3995,8 @@ static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
 	page = alloc_pages_node(node, flags, order);
 	if (page) {
 		ptr = page_address(page);
-		mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE,
-				    1 << order);
+		mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE_B,
+				    PAGE_SIZE << order);
 	}
 
 	return kmalloc_large_node_hook(ptr, size, flags);
@@ -4127,8 +4127,8 @@ void kfree(const void *x)
 
 		BUG_ON(!PageCompound(page));
 		kfree_hook(object);
-		mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE,
-				    -(1 << order));
+		mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE_B,
+				    -(PAGE_SIZE << order));
 		__free_pages(page, order);
 		return;
 	}
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 749d239c62b2..2ac43664aba4 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4222,7 +4222,8 @@ int node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned int order)
 	 * unmapped file backed pages.
 	 */
 	if (node_pagecache_reclaimable(pgdat) <= pgdat->min_unmapped_pages &&
-	    node_page_state(pgdat, NR_SLAB_RECLAIMABLE) <= pgdat->min_slab_pages)
+	    node_page_state_pages(pgdat, NR_SLAB_RECLAIMABLE_B) <=
+	    pgdat->min_slab_pages)
 		return NODE_RECLAIM_FULL;
 
 	/*
diff --git a/mm/workingset.c b/mm/workingset.c
index 50b7937bab32..b199726924dd 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -486,8 +486,10 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker,
 		for (pages = 0, i = 0; i < NR_LRU_LISTS; i++)
 			pages += lruvec_page_state_local(lruvec,
 							 NR_LRU_BASE + i);
-		pages += lruvec_page_state_local(lruvec, NR_SLAB_RECLAIMABLE);
-		pages += lruvec_page_state_local(lruvec, NR_SLAB_UNRECLAIMABLE);
+		pages += lruvec_page_state_local(
+			lruvec, NR_SLAB_RECLAIMABLE_B) >> PAGE_SHIFT;
+		pages += lruvec_page_state_local(
+			lruvec, NR_SLAB_UNRECLAIMABLE_B) >> PAGE_SHIFT;
 	} else
 #endif
 		pages = node_present_pages(sc->nid);
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 04/19] mm: slub: implement SLUB version of obj_to_index()
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
                   ` (2 preceding siblings ...)
  2020-06-23  1:58 ` [PATCH v7 03/19] mm: memcg: convert vmstat slab counters to bytes Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 05/19] mm: memcontrol: decouple reference counting from page accounting Roman Gushchin
                   ` (15 subsequent siblings)
  19 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

This commit implements SLUB version of the obj_to_index() function, which
will be required to calculate the offset of obj_cgroup in the obj_cgroups
vector to store/obtain the objcg ownership data.

To make it faster, let's repeat the SLAB's trick introduced by commit
6a2d7a955d8d ("SLAB: use a multiply instead of a divide in
obj_to_index()") and avoid an expensive division.

Vlastimil Babka noticed, that SLUB does have already a similar function
called slab_index(), which is defined only if SLUB_DEBUG is enabled.  The
function does a similar math, but with a division, and it also takes a
page address instead of a page pointer.

Let's remove slab_index() and replace it with the new helper
__obj_to_index(), which takes a page address.  obj_to_index() will be a
simple wrapper taking a page pointer and passing page_address(page) into
__obj_to_index().

Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 include/linux/slub_def.h | 16 ++++++++++++++++
 mm/slub.c                | 15 +++++----------
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index d2153789bd9f..30e91c83d401 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -8,6 +8,7 @@
  * (C) 2007 SGI, Christoph Lameter
  */
 #include <linux/kobject.h>
+#include <linux/reciprocal_div.h>
 
 enum stat_item {
 	ALLOC_FASTPATH,		/* Allocation from cpu slab */
@@ -86,6 +87,7 @@ struct kmem_cache {
 	unsigned long min_partial;
 	unsigned int size;	/* The size of an object including metadata */
 	unsigned int object_size;/* The size of an object without metadata */
+	struct reciprocal_value reciprocal_size;
 	unsigned int offset;	/* Free pointer offset */
 #ifdef CONFIG_SLUB_CPU_PARTIAL
 	/* Number of per cpu partial objects to keep around */
@@ -182,4 +184,18 @@ static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
 	return result;
 }
 
+/* Determine object index from a given position */
+static inline unsigned int __obj_to_index(const struct kmem_cache *cache,
+					  void *addr, void *obj)
+{
+	return reciprocal_divide(kasan_reset_tag(obj) - addr,
+				 cache->reciprocal_size);
+}
+
+static inline unsigned int obj_to_index(const struct kmem_cache *cache,
+					const struct page *page, void *obj)
+{
+	return __obj_to_index(cache, page_address(page), obj);
+}
+
 #endif /* _LINUX_SLUB_DEF_H */
diff --git a/mm/slub.c b/mm/slub.c
index c79d33cbe815..aa8d18824e62 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -317,12 +317,6 @@ static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
 		__p < (__addr) + (__objects) * (__s)->size; \
 		__p += (__s)->size)
 
-/* Determine object index from a given position */
-static inline unsigned int slab_index(void *p, struct kmem_cache *s, void *addr)
-{
-	return (kasan_reset_tag(p) - addr) / s->size;
-}
-
 static inline unsigned int order_objects(unsigned int order, unsigned int size)
 {
 	return ((unsigned int)PAGE_SIZE << order) / size;
@@ -465,7 +459,7 @@ static unsigned long *get_map(struct kmem_cache *s, struct page *page)
 	bitmap_zero(object_map, page->objects);
 
 	for (p = page->freelist; p; p = get_freepointer(s, p))
-		set_bit(slab_index(p, s, addr), object_map);
+		set_bit(__obj_to_index(s, addr, p), object_map);
 
 	return object_map;
 }
@@ -3758,6 +3752,7 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order)
 	 */
 	size = ALIGN(size, s->align);
 	s->size = size;
+	s->reciprocal_size = reciprocal_value(size);
 	if (forced_order >= 0)
 		order = forced_order;
 	else
@@ -3862,7 +3857,7 @@ static void list_slab_objects(struct kmem_cache *s, struct page *page,
 	map = get_map(s, page);
 	for_each_object(p, s, addr, page->objects) {
 
-		if (!test_bit(slab_index(p, s, addr), map)) {
+		if (!test_bit(__obj_to_index(s, addr, p), map)) {
 			pr_err("INFO: Object 0x%p @offset=%tu\n", p, p - addr);
 			print_tracking(s, p);
 		}
@@ -4578,7 +4573,7 @@ static void validate_slab(struct kmem_cache *s, struct page *page)
 	/* Now we know that a valid freelist exists */
 	map = get_map(s, page);
 	for_each_object(p, s, addr, page->objects) {
-		u8 val = test_bit(slab_index(p, s, addr), map) ?
+		u8 val = test_bit(__obj_to_index(s, addr, p), map) ?
 			 SLUB_RED_INACTIVE : SLUB_RED_ACTIVE;
 
 		if (!check_object(s, page, p, val))
@@ -4769,7 +4764,7 @@ static void process_slab(struct loc_track *t, struct kmem_cache *s,
 
 	map = get_map(s, page);
 	for_each_object(p, s, addr, page->objects)
-		if (!test_bit(slab_index(p, s, addr), map))
+		if (!test_bit(__obj_to_index(s, addr, p), map))
 			add_location(t, s, get_track(s, p, alloc));
 	put_map(map);
 }
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 05/19] mm: memcontrol: decouple reference counting from page accounting
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
                   ` (3 preceding siblings ...)
  2020-06-23  1:58 ` [PATCH v7 04/19] mm: slub: implement SLUB version of obj_to_index() Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 06/19] mm: memcg/slab: obj_cgroup API Roman Gushchin
                   ` (14 subsequent siblings)
  19 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

From: Johannes Weiner <hannes@cmpxchg.org>

The reference counting of a memcg is currently coupled directly to how
many 4k pages are charged to it.  This doesn't work well with Roman's new
slab controller, which maintains pools of objects and doesn't want to keep
an extra balance sheet for the pages backing those objects.

This unusual refcounting design (reference counts usually track pointers
to an object) is only for historical reasons: memcg used to not take any
css references and simply stalled offlining until all charges had been
reparented and the page counters had dropped to zero.  When we got rid of
the reparenting requirement, the simple mechanical translation was to take
a reference for every charge.

More historical context can be found in commit e8ea14cc6ead ("mm:
memcontrol: take a css reference for each charged page"), commit
64f219938941 ("mm: memcontrol: remove obsolete kmemcg pinning tricks") and
commit b2052564e66d ("mm: memcontrol: continue cache reclaim from offlined
groups").

The new slab controller exposes the limitations in this scheme, so let's
switch it to a more idiomatic reference counting model based on actual
kernel pointers to the memcg:

- The per-cpu stock holds a reference to the memcg its caching

- User pages hold a reference for their page->mem_cgroup. Transparent
  huge pages will no longer acquire tail references in advance, we'll
  get them if needed during the split.

- Kernel pages hold a reference for their page->mem_cgroup

- Pages allocated in the root cgroup will acquire and release css
  references for simplicity. css_get() and css_put() optimize that.

- The current memcg_charge_slab() already hacked around the per-charge
  references; this change gets rid of that as well.

Roman:
1) Rebased on top of the current mm tree: added css_get() in
   mem_cgroup_charge(), dropped mem_cgroup_try_charge() part
2) I've reformatted commit references in the commit log to make
   checkpatch.pl happy.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 mm/memcontrol.c | 37 +++++++++++++++++++++----------------
 mm/slab.h       |  2 --
 2 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a6216f7369b2..3e5597f8dec5 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2094,13 +2094,17 @@ static void drain_stock(struct memcg_stock_pcp *stock)
 {
 	struct mem_cgroup *old = stock->cached;
 
+	if (!old)
+		return;
+
 	if (stock->nr_pages) {
 		page_counter_uncharge(&old->memory, stock->nr_pages);
 		if (do_memsw_account())
 			page_counter_uncharge(&old->memsw, stock->nr_pages);
-		css_put_many(&old->css, stock->nr_pages);
 		stock->nr_pages = 0;
 	}
+
+	css_put(&old->css);
 	stock->cached = NULL;
 }
 
@@ -2136,6 +2140,7 @@ static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
 	stock = this_cpu_ptr(&memcg_stock);
 	if (stock->cached != memcg) { /* reset if necessary */
 		drain_stock(stock);
+		css_get(&memcg->css);
 		stock->cached = memcg;
 	}
 	stock->nr_pages += nr_pages;
@@ -2594,12 +2599,10 @@ static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
 	page_counter_charge(&memcg->memory, nr_pages);
 	if (do_memsw_account())
 		page_counter_charge(&memcg->memsw, nr_pages);
-	css_get_many(&memcg->css, nr_pages);
 
 	return 0;
 
 done_restock:
-	css_get_many(&memcg->css, batch);
 	if (batch > nr_pages)
 		refill_stock(memcg, batch - nr_pages);
 
@@ -2657,8 +2660,6 @@ static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
 	page_counter_uncharge(&memcg->memory, nr_pages);
 	if (do_memsw_account())
 		page_counter_uncharge(&memcg->memsw, nr_pages);
-
-	css_put_many(&memcg->css, nr_pages);
 }
 #endif
 
@@ -2966,6 +2967,7 @@ int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order)
 		if (!ret) {
 			page->mem_cgroup = memcg;
 			__SetPageKmemcg(page);
+			return 0;
 		}
 	}
 	css_put(&memcg->css);
@@ -2988,12 +2990,11 @@ void __memcg_kmem_uncharge_page(struct page *page, int order)
 	VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page);
 	__memcg_kmem_uncharge(memcg, nr_pages);
 	page->mem_cgroup = NULL;
+	css_put(&memcg->css);
 
 	/* slab pages do not have PageKmemcg flag set */
 	if (PageKmemcg(page))
 		__ClearPageKmemcg(page);
-
-	css_put_many(&memcg->css, nr_pages);
 }
 #endif /* CONFIG_MEMCG_KMEM */
 
@@ -3005,13 +3006,16 @@ void __memcg_kmem_uncharge_page(struct page *page, int order)
  */
 void mem_cgroup_split_huge_fixup(struct page *head)
 {
+	struct mem_cgroup *memcg = head->mem_cgroup;
 	int i;
 
 	if (mem_cgroup_disabled())
 		return;
 
-	for (i = 1; i < HPAGE_PMD_NR; i++)
-		head[i].mem_cgroup = head->mem_cgroup;
+	for (i = 1; i < HPAGE_PMD_NR; i++) {
+		css_get(&memcg->css);
+		head[i].mem_cgroup = memcg;
+	}
 }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
@@ -5456,7 +5460,10 @@ static int mem_cgroup_move_account(struct page *page,
 	 */
 	smp_mb();
 
-	page->mem_cgroup = to; 	/* caller should have done css_get */
+	css_get(&to->css);
+	css_put(&from->css);
+
+	page->mem_cgroup = to;
 
 	__unlock_page_memcg(from);
 
@@ -6506,6 +6513,7 @@ int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask)
 	if (ret)
 		goto out_put;
 
+	css_get(&memcg->css);
 	commit_charge(page, memcg);
 
 	local_irq_disable();
@@ -6560,9 +6568,6 @@ static void uncharge_batch(const struct uncharge_gather *ug)
 	__this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, ug->nr_pages);
 	memcg_check_events(ug->memcg, ug->dummy_page);
 	local_irq_restore(flags);
-
-	if (!mem_cgroup_is_root(ug->memcg))
-		css_put_many(&ug->memcg->css, ug->nr_pages);
 }
 
 static void uncharge_page(struct page *page, struct uncharge_gather *ug)
@@ -6600,6 +6605,7 @@ static void uncharge_page(struct page *page, struct uncharge_gather *ug)
 
 	ug->dummy_page = page;
 	page->mem_cgroup = NULL;
+	css_put(&ug->memcg->css);
 }
 
 static void uncharge_list(struct list_head *page_list)
@@ -6705,8 +6711,8 @@ void mem_cgroup_migrate(struct page *oldpage, struct page *newpage)
 	page_counter_charge(&memcg->memory, nr_pages);
 	if (do_memsw_account())
 		page_counter_charge(&memcg->memsw, nr_pages);
-	css_get_many(&memcg->css, nr_pages);
 
+	css_get(&memcg->css);
 	commit_charge(newpage, memcg);
 
 	local_irq_save(flags);
@@ -6943,8 +6949,7 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
 	mem_cgroup_charge_statistics(memcg, page, -nr_entries);
 	memcg_check_events(memcg, page);
 
-	if (!mem_cgroup_is_root(memcg))
-		css_put_many(&memcg->css, nr_entries);
+	css_put(&memcg->css);
 }
 
 /**
diff --git a/mm/slab.h b/mm/slab.h
index cc6afddd5632..1e2d80991904 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -401,9 +401,7 @@ static __always_inline int memcg_charge_slab(struct page *page,
 	lruvec = mem_cgroup_lruvec(memcg, page_pgdat(page));
 	mod_lruvec_state(lruvec, cache_vmstat_idx(s), nr_pages << PAGE_SHIFT);
 
-	/* transer try_charge() page references to kmem_cache */
 	percpu_ref_get_many(&s->memcg_params.refcnt, nr_pages);
-	css_put_many(&memcg->css, nr_pages);
 out:
 	css_put(&memcg->css);
 	return ret;
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 06/19] mm: memcg/slab: obj_cgroup API
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
                   ` (4 preceding siblings ...)
  2020-06-23  1:58 ` [PATCH v7 05/19] mm: memcontrol: decouple reference counting from page accounting Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 07/19] mm: memcg/slab: allocate obj_cgroups for non-root slab pages Roman Gushchin
                   ` (13 subsequent siblings)
  19 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

Obj_cgroup API provides an ability to account sub-page sized kernel
objects, which potentially outlive the original memory cgroup.

The top-level API consists of the following functions:
  bool obj_cgroup_tryget(struct obj_cgroup *objcg);
  void obj_cgroup_get(struct obj_cgroup *objcg);
  void obj_cgroup_put(struct obj_cgroup *objcg);

  int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size);
  void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size);

  struct mem_cgroup *obj_cgroup_memcg(struct obj_cgroup *objcg);
  struct obj_cgroup *get_obj_cgroup_from_current(void);

Object cgroup is basically a pointer to a memory cgroup with a per-cpu
reference counter.  It substitutes a memory cgroup in places where it's
necessary to charge a custom amount of bytes instead of pages.

All charged memory rounded down to pages is charged to the corresponding
memory cgroup using __memcg_kmem_charge().

It implements reparenting: on memcg offlining it's getting reattached to
the parent memory cgroup.  Each online memory cgroup has an associated
active object cgroup to handle new allocations and the list of all
attached object cgroups.  On offlining of a cgroup this list is reparented
and for each object cgroup in the list the memcg pointer is swapped to the
parent memory cgroup.  It prevents long-living objects from pinning the
original memory cgroup in the memory.

The implementation is based on byte-sized per-cpu stocks.  A sub-page
sized leftover is stored in an atomic field, which is a part of obj_cgroup
object.  So on cgroup offlining the leftover is automatically reparented.

memcg->objcg is rcu protected.  objcg->memcg is a raw pointer, which is
always pointing at a memory cgroup, but can be atomically swapped to the
parent memory cgroup.  So a user must ensure the lifetime of the
cgroup, e.g.  grab rcu_read_lock or css_set_lock.

Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 include/linux/memcontrol.h |  51 +++++++
 mm/memcontrol.c            | 288 ++++++++++++++++++++++++++++++++++++-
 2 files changed, 338 insertions(+), 1 deletion(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index b250f8197710..f2f9d5d6b7d1 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -23,6 +23,7 @@
 #include <linux/page-flags.h>
 
 struct mem_cgroup;
+struct obj_cgroup;
 struct page;
 struct mm_struct;
 struct kmem_cache;
@@ -192,6 +193,22 @@ struct memcg_cgwb_frn {
 	struct wb_completion done;	/* tracks in-flight foreign writebacks */
 };
 
+/*
+ * Bucket for arbitrarily byte-sized objects charged to a memory
+ * cgroup. The bucket can be reparented in one piece when the cgroup
+ * is destroyed, without having to round up the individual references
+ * of all live memory objects in the wild.
+ */
+struct obj_cgroup {
+	struct percpu_ref refcnt;
+	struct mem_cgroup *memcg;
+	atomic_t nr_charged_bytes;
+	union {
+		struct list_head list;
+		struct rcu_head rcu;
+	};
+};
+
 /*
  * The memory controller data structure. The memory controller controls both
  * page cache and RSS per cgroup. We would eventually like to provide
@@ -301,6 +318,8 @@ struct mem_cgroup {
 	int kmemcg_id;
 	enum memcg_kmem_state kmem_state;
 	struct list_head kmem_caches;
+	struct obj_cgroup __rcu *objcg;
+	struct list_head objcg_list; /* list of inherited objcgs */
 #endif
 
 #ifdef CONFIG_CGROUP_WRITEBACK
@@ -416,6 +435,33 @@ struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css){
 	return css ? container_of(css, struct mem_cgroup, css) : NULL;
 }
 
+static inline bool obj_cgroup_tryget(struct obj_cgroup *objcg)
+{
+	return percpu_ref_tryget(&objcg->refcnt);
+}
+
+static inline void obj_cgroup_get(struct obj_cgroup *objcg)
+{
+	percpu_ref_get(&objcg->refcnt);
+}
+
+static inline void obj_cgroup_put(struct obj_cgroup *objcg)
+{
+	percpu_ref_put(&objcg->refcnt);
+}
+
+/*
+ * After the initialization objcg->memcg is always pointing at
+ * a valid memcg, but can be atomically swapped to the parent memcg.
+ *
+ * The caller must ensure that the returned memcg won't be released:
+ * e.g. acquire the rcu_read_lock or css_set_lock.
+ */
+static inline struct mem_cgroup *obj_cgroup_memcg(struct obj_cgroup *objcg)
+{
+	return READ_ONCE(objcg->memcg);
+}
+
 static inline void mem_cgroup_put(struct mem_cgroup *memcg)
 {
 	if (memcg)
@@ -1368,6 +1414,11 @@ void __memcg_kmem_uncharge(struct mem_cgroup *memcg, unsigned int nr_pages);
 int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order);
 void __memcg_kmem_uncharge_page(struct page *page, int order);
 
+struct obj_cgroup *get_obj_cgroup_from_current(void);
+
+int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size);
+void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size);
+
 extern struct static_key_false memcg_kmem_enabled_key;
 extern struct workqueue_struct *memcg_kmem_cache_wq;
 
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 3e5597f8dec5..407f90f7a2f7 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -257,6 +257,98 @@ struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr)
 }
 
 #ifdef CONFIG_MEMCG_KMEM
+extern spinlock_t css_set_lock;
+
+static void obj_cgroup_release(struct percpu_ref *ref)
+{
+	struct obj_cgroup *objcg = container_of(ref, struct obj_cgroup, refcnt);
+	struct mem_cgroup *memcg;
+	unsigned int nr_bytes;
+	unsigned int nr_pages;
+	unsigned long flags;
+
+	/*
+	 * At this point all allocated objects are freed, and
+	 * objcg->nr_charged_bytes can't have an arbitrary byte value.
+	 * However, it can be PAGE_SIZE or (x * PAGE_SIZE).
+	 *
+	 * The following sequence can lead to it:
+	 * 1) CPU0: objcg == stock->cached_objcg
+	 * 2) CPU1: we do a small allocation (e.g. 92 bytes),
+	 *          PAGE_SIZE bytes are charged
+	 * 3) CPU1: a process from another memcg is allocating something,
+	 *          the stock if flushed,
+	 *          objcg->nr_charged_bytes = PAGE_SIZE - 92
+	 * 5) CPU0: we do release this object,
+	 *          92 bytes are added to stock->nr_bytes
+	 * 6) CPU0: stock is flushed,
+	 *          92 bytes are added to objcg->nr_charged_bytes
+	 *
+	 * In the result, nr_charged_bytes == PAGE_SIZE.
+	 * This page will be uncharged in obj_cgroup_release().
+	 */
+	nr_bytes = atomic_read(&objcg->nr_charged_bytes);
+	WARN_ON_ONCE(nr_bytes & (PAGE_SIZE - 1));
+	nr_pages = nr_bytes >> PAGE_SHIFT;
+
+	spin_lock_irqsave(&css_set_lock, flags);
+	memcg = obj_cgroup_memcg(objcg);
+	if (nr_pages)
+		__memcg_kmem_uncharge(memcg, nr_pages);
+	list_del(&objcg->list);
+	mem_cgroup_put(memcg);
+	spin_unlock_irqrestore(&css_set_lock, flags);
+
+	percpu_ref_exit(ref);
+	kfree_rcu(objcg, rcu);
+}
+
+static struct obj_cgroup *obj_cgroup_alloc(void)
+{
+	struct obj_cgroup *objcg;
+	int ret;
+
+	objcg = kzalloc(sizeof(struct obj_cgroup), GFP_KERNEL);
+	if (!objcg)
+		return NULL;
+
+	ret = percpu_ref_init(&objcg->refcnt, obj_cgroup_release, 0,
+			      GFP_KERNEL);
+	if (ret) {
+		kfree(objcg);
+		return NULL;
+	}
+	INIT_LIST_HEAD(&objcg->list);
+	return objcg;
+}
+
+static void memcg_reparent_objcgs(struct mem_cgroup *memcg,
+				  struct mem_cgroup *parent)
+{
+	struct obj_cgroup *objcg, *iter;
+
+	objcg = rcu_replace_pointer(memcg->objcg, NULL, true);
+
+	spin_lock_irq(&css_set_lock);
+
+	/* Move active objcg to the parent's list */
+	xchg(&objcg->memcg, parent);
+	css_get(&parent->css);
+	list_add(&objcg->list, &parent->objcg_list);
+
+	/* Move already reparented objcgs to the parent's list */
+	list_for_each_entry(iter, &memcg->objcg_list, list) {
+		css_get(&parent->css);
+		xchg(&iter->memcg, parent);
+		css_put(&memcg->css);
+	}
+	list_splice(&memcg->objcg_list, &parent->objcg_list);
+
+	spin_unlock_irq(&css_set_lock);
+
+	percpu_ref_kill(&objcg->refcnt);
+}
+
 /*
  * This will be the memcg's index in each cache's ->memcg_params.memcg_caches.
  * The main reason for not using cgroup id for this:
@@ -2047,6 +2139,12 @@ EXPORT_SYMBOL(unlock_page_memcg);
 struct memcg_stock_pcp {
 	struct mem_cgroup *cached; /* this never be root cgroup */
 	unsigned int nr_pages;
+
+#ifdef CONFIG_MEMCG_KMEM
+	struct obj_cgroup *cached_objcg;
+	unsigned int nr_bytes;
+#endif
+
 	struct work_struct work;
 	unsigned long flags;
 #define FLUSHING_CACHED_CHARGE	0
@@ -2054,6 +2152,22 @@ struct memcg_stock_pcp {
 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
 static DEFINE_MUTEX(percpu_charge_mutex);
 
+#ifdef CONFIG_MEMCG_KMEM
+static void drain_obj_stock(struct memcg_stock_pcp *stock);
+static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
+				     struct mem_cgroup *root_memcg);
+
+#else
+static inline void drain_obj_stock(struct memcg_stock_pcp *stock)
+{
+}
+static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
+				     struct mem_cgroup *root_memcg)
+{
+	return false;
+}
+#endif
+
 /**
  * consume_stock: Try to consume stocked charge on this cpu.
  * @memcg: memcg to consume from.
@@ -2120,6 +2234,7 @@ static void drain_local_stock(struct work_struct *dummy)
 	local_irq_save(flags);
 
 	stock = this_cpu_ptr(&memcg_stock);
+	drain_obj_stock(stock);
 	drain_stock(stock);
 	clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
 
@@ -2179,6 +2294,8 @@ static void drain_all_stock(struct mem_cgroup *root_memcg)
 		if (memcg && stock->nr_pages &&
 		    mem_cgroup_is_descendant(memcg, root_memcg))
 			flush = true;
+		if (obj_stock_flush_required(stock, root_memcg))
+			flush = true;
 		rcu_read_unlock();
 
 		if (flush &&
@@ -2705,6 +2822,30 @@ struct mem_cgroup *mem_cgroup_from_obj(void *p)
 	return page->mem_cgroup;
 }
 
+__always_inline struct obj_cgroup *get_obj_cgroup_from_current(void)
+{
+	struct obj_cgroup *objcg = NULL;
+	struct mem_cgroup *memcg;
+
+	if (unlikely(!current->mm && !current->active_memcg))
+		return NULL;
+
+	rcu_read_lock();
+	if (unlikely(current->active_memcg))
+		memcg = rcu_dereference(current->active_memcg);
+	else
+		memcg = mem_cgroup_from_task(current);
+
+	for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) {
+		objcg = rcu_dereference(memcg->objcg);
+		if (objcg && obj_cgroup_tryget(objcg))
+			break;
+	}
+	rcu_read_unlock();
+
+	return objcg;
+}
+
 static int memcg_alloc_cache_id(void)
 {
 	int id, size;
@@ -2996,6 +3137,140 @@ void __memcg_kmem_uncharge_page(struct page *page, int order)
 	if (PageKmemcg(page))
 		__ClearPageKmemcg(page);
 }
+
+static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
+{
+	struct memcg_stock_pcp *stock;
+	unsigned long flags;
+	bool ret = false;
+
+	local_irq_save(flags);
+
+	stock = this_cpu_ptr(&memcg_stock);
+	if (objcg == stock->cached_objcg && stock->nr_bytes >= nr_bytes) {
+		stock->nr_bytes -= nr_bytes;
+		ret = true;
+	}
+
+	local_irq_restore(flags);
+
+	return ret;
+}
+
+static void drain_obj_stock(struct memcg_stock_pcp *stock)
+{
+	struct obj_cgroup *old = stock->cached_objcg;
+
+	if (!old)
+		return;
+
+	if (stock->nr_bytes) {
+		unsigned int nr_pages = stock->nr_bytes >> PAGE_SHIFT;
+		unsigned int nr_bytes = stock->nr_bytes & (PAGE_SIZE - 1);
+
+		if (nr_pages) {
+			rcu_read_lock();
+			__memcg_kmem_uncharge(obj_cgroup_memcg(old), nr_pages);
+			rcu_read_unlock();
+		}
+
+		/*
+		 * The leftover is flushed to the centralized per-memcg value.
+		 * On the next attempt to refill obj stock it will be moved
+		 * to a per-cpu stock (probably, on an other CPU), see
+		 * refill_obj_stock().
+		 *
+		 * How often it's flushed is a trade-off between the memory
+		 * limit enforcement accuracy and potential CPU contention,
+		 * so it might be changed in the future.
+		 */
+		atomic_add(nr_bytes, &old->nr_charged_bytes);
+		stock->nr_bytes = 0;
+	}
+
+	obj_cgroup_put(old);
+	stock->cached_objcg = NULL;
+}
+
+static bool obj_stock_flush_required(struct memcg_stock_pcp *stock,
+				     struct mem_cgroup *root_memcg)
+{
+	struct mem_cgroup *memcg;
+
+	if (stock->cached_objcg) {
+		memcg = obj_cgroup_memcg(stock->cached_objcg);
+		if (memcg && mem_cgroup_is_descendant(memcg, root_memcg))
+			return true;
+	}
+
+	return false;
+}
+
+static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes)
+{
+	struct memcg_stock_pcp *stock;
+	unsigned long flags;
+
+	local_irq_save(flags);
+
+	stock = this_cpu_ptr(&memcg_stock);
+	if (stock->cached_objcg != objcg) { /* reset if necessary */
+		drain_obj_stock(stock);
+		obj_cgroup_get(objcg);
+		stock->cached_objcg = objcg;
+		stock->nr_bytes = atomic_xchg(&objcg->nr_charged_bytes, 0);
+	}
+	stock->nr_bytes += nr_bytes;
+
+	if (stock->nr_bytes > PAGE_SIZE)
+		drain_obj_stock(stock);
+
+	local_irq_restore(flags);
+}
+
+int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size)
+{
+	struct mem_cgroup *memcg;
+	unsigned int nr_pages, nr_bytes;
+	int ret;
+
+	if (consume_obj_stock(objcg, size))
+		return 0;
+
+	/*
+	 * In theory, memcg->nr_charged_bytes can have enough
+	 * pre-charged bytes to satisfy the allocation. However,
+	 * flushing memcg->nr_charged_bytes requires two atomic
+	 * operations, and memcg->nr_charged_bytes can't be big,
+	 * so it's better to ignore it and try grab some new pages.
+	 * memcg->nr_charged_bytes will be flushed in
+	 * refill_obj_stock(), called from this function or
+	 * independently later.
+	 */
+	rcu_read_lock();
+	memcg = obj_cgroup_memcg(objcg);
+	css_get(&memcg->css);
+	rcu_read_unlock();
+
+	nr_pages = size >> PAGE_SHIFT;
+	nr_bytes = size & (PAGE_SIZE - 1);
+
+	if (nr_bytes)
+		nr_pages += 1;
+
+	ret = __memcg_kmem_charge(memcg, gfp, nr_pages);
+	if (!ret && nr_bytes)
+		refill_obj_stock(objcg, PAGE_SIZE - nr_bytes);
+
+	css_put(&memcg->css);
+	return ret;
+}
+
+void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size)
+{
+	refill_obj_stock(objcg, size);
+}
+
 #endif /* CONFIG_MEMCG_KMEM */
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -3416,6 +3691,7 @@ static void memcg_flush_percpu_vmevents(struct mem_cgroup *memcg)
 #ifdef CONFIG_MEMCG_KMEM
 static int memcg_online_kmem(struct mem_cgroup *memcg)
 {
+	struct obj_cgroup *objcg;
 	int memcg_id;
 
 	if (cgroup_memory_nokmem)
@@ -3428,6 +3704,14 @@ static int memcg_online_kmem(struct mem_cgroup *memcg)
 	if (memcg_id < 0)
 		return memcg_id;
 
+	objcg = obj_cgroup_alloc();
+	if (!objcg) {
+		memcg_free_cache_id(memcg_id);
+		return -ENOMEM;
+	}
+	objcg->memcg = memcg;
+	rcu_assign_pointer(memcg->objcg, objcg);
+
 	static_branch_inc(&memcg_kmem_enabled_key);
 	/*
 	 * A memory cgroup is considered kmem-online as soon as it gets
@@ -3463,9 +3747,10 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg)
 		parent = root_mem_cgroup;
 
 	/*
-	 * Deactivate and reparent kmem_caches.
+	 * Deactivate and reparent kmem_caches and objcgs.
 	 */
 	memcg_deactivate_kmem_caches(memcg, parent);
+	memcg_reparent_objcgs(memcg, parent);
 
 	kmemcg_id = memcg->kmemcg_id;
 	BUG_ON(kmemcg_id < 0);
@@ -5034,6 +5319,7 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
 	memcg->socket_pressure = jiffies;
 #ifdef CONFIG_MEMCG_KMEM
 	memcg->kmemcg_id = -1;
+	INIT_LIST_HEAD(&memcg->objcg_list);
 #endif
 #ifdef CONFIG_CGROUP_WRITEBACK
 	INIT_LIST_HEAD(&memcg->cgwb_list);
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 07/19] mm: memcg/slab: allocate obj_cgroups for non-root slab pages
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
                   ` (5 preceding siblings ...)
  2020-06-23  1:58 ` [PATCH v7 06/19] mm: memcg/slab: obj_cgroup API Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 08/19] mm: memcg/slab: save obj_cgroup for non-root slab objects Roman Gushchin
                   ` (12 subsequent siblings)
  19 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

Allocate and release memory to store obj_cgroup pointers for each non-root
slab page. Reuse page->mem_cgroup pointer to store a pointer to the
allocated space.

This commit temporarily increases the memory footprint of the kernel memory
accounting. To store obj_cgroup pointers we'll need a place for an
objcg_pointer for each allocated object. However, the following patches
in the series will enable sharing of slab pages between memory cgroups,
which will dramatically increase the total slab utilization. And the final
memory footprint will be significantly smaller than before.

To distinguish between obj_cgroups and memcg pointers in case when it's
not obvious which one is used (as in page_cgroup_ino()), let's always set
the lowest bit in the obj_cgroup case. The original obj_cgroups
pointer is marked to be ignored by kmemleak, which otherwise would
report a memory leak for each allocated vector.

Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 include/linux/mm_types.h |  5 +++-
 include/linux/slab_def.h |  6 +++++
 include/linux/slub_def.h |  5 ++++
 mm/memcontrol.c          | 17 ++++++++++---
 mm/slab.h                | 52 ++++++++++++++++++++++++++++++++++++++++
 5 files changed, 81 insertions(+), 4 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 64ede5f150dc..0277fbab7c93 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -198,7 +198,10 @@ struct page {
 	atomic_t _refcount;
 
 #ifdef CONFIG_MEMCG
-	struct mem_cgroup *mem_cgroup;
+	union {
+		struct mem_cgroup *mem_cgroup;
+		struct obj_cgroup **obj_cgroups;
+	};
 #endif
 
 	/*
diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index abc7de77b988..ccda7b9669a5 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -114,4 +114,10 @@ static inline unsigned int obj_to_index(const struct kmem_cache *cache,
 	return reciprocal_divide(offset, cache->reciprocal_buffer_size);
 }
 
+static inline int objs_per_slab_page(const struct kmem_cache *cache,
+				     const struct page *page)
+{
+	return cache->num;
+}
+
 #endif	/* _LINUX_SLAB_DEF_H */
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 30e91c83d401..f87302dcfe8c 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -198,4 +198,9 @@ static inline unsigned int obj_to_index(const struct kmem_cache *cache,
 	return __obj_to_index(cache, page_address(page), obj);
 }
 
+static inline int objs_per_slab_page(const struct kmem_cache *cache,
+				     const struct page *page)
+{
+	return page->objects;
+}
 #endif /* _LINUX_SLUB_DEF_H */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 407f90f7a2f7..60e3f3ca75ca 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -569,10 +569,21 @@ ino_t page_cgroup_ino(struct page *page)
 	unsigned long ino = 0;
 
 	rcu_read_lock();
-	if (PageSlab(page) && !PageTail(page))
+	if (PageSlab(page) && !PageTail(page)) {
 		memcg = memcg_from_slab_page(page);
-	else
-		memcg = READ_ONCE(page->mem_cgroup);
+	} else {
+		memcg = page->mem_cgroup;
+
+		/*
+		 * The lowest bit set means that memcg isn't a valid
+		 * memcg pointer, but a obj_cgroups pointer.
+		 * In this case the page is shared and doesn't belong
+		 * to any specific memory cgroup.
+		 */
+		if ((unsigned long) memcg & 0x1UL)
+			memcg = NULL;
+	}
+
 	while (memcg && !(memcg->css.flags & CSS_ONLINE))
 		memcg = parent_mem_cgroup(memcg);
 	if (memcg)
diff --git a/mm/slab.h b/mm/slab.h
index 1e2d80991904..7d175c2f1a61 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -109,6 +109,7 @@ struct memcg_cache_params {
 #include <linux/kmemleak.h>
 #include <linux/random.h>
 #include <linux/sched/mm.h>
+#include <linux/kmemleak.h>
 
 /*
  * State of the slab allocator.
@@ -347,6 +348,18 @@ static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 	return s->memcg_params.root_cache;
 }
 
+static inline struct obj_cgroup **page_obj_cgroups(struct page *page)
+{
+	/*
+	 * page->mem_cgroup and page->obj_cgroups are sharing the same
+	 * space. To distinguish between them in case we don't know for sure
+	 * that the page is a slab page (e.g. page_cgroup_ino()), let's
+	 * always set the lowest bit of obj_cgroups.
+	 */
+	return (struct obj_cgroup **)
+		((unsigned long)page->obj_cgroups & ~0x1UL);
+}
+
 /*
  * Expects a pointer to a slab page. Please note, that PageSlab() check
  * isn't sufficient, as it returns true also for tail compound slab pages,
@@ -434,6 +447,28 @@ static __always_inline void memcg_uncharge_slab(struct page *page, int order,
 	percpu_ref_put_many(&s->memcg_params.refcnt, nr_pages);
 }
 
+static inline int memcg_alloc_page_obj_cgroups(struct page *page,
+					       struct kmem_cache *s, gfp_t gfp)
+{
+	unsigned int objects = objs_per_slab_page(s, page);
+	void *vec;
+
+	vec = kcalloc_node(objects, sizeof(struct obj_cgroup *), gfp,
+			   page_to_nid(page));
+	if (!vec)
+		return -ENOMEM;
+
+	kmemleak_not_leak(vec);
+	page->obj_cgroups = (struct obj_cgroup **) ((unsigned long)vec | 0x1UL);
+	return 0;
+}
+
+static inline void memcg_free_page_obj_cgroups(struct page *page)
+{
+	kfree(page_obj_cgroups(page));
+	page->obj_cgroups = NULL;
+}
+
 extern void slab_init_memcg_params(struct kmem_cache *);
 extern void memcg_link_cache(struct kmem_cache *s, struct mem_cgroup *memcg);
 
@@ -483,6 +518,16 @@ static inline void memcg_uncharge_slab(struct page *page, int order,
 {
 }
 
+static inline int memcg_alloc_page_obj_cgroups(struct page *page,
+					       struct kmem_cache *s, gfp_t gfp)
+{
+	return 0;
+}
+
+static inline void memcg_free_page_obj_cgroups(struct page *page)
+{
+}
+
 static inline void slab_init_memcg_params(struct kmem_cache *s)
 {
 }
@@ -509,12 +554,18 @@ static __always_inline int charge_slab_page(struct page *page,
 					    gfp_t gfp, int order,
 					    struct kmem_cache *s)
 {
+	int ret;
+
 	if (is_root_cache(s)) {
 		mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
 				    PAGE_SIZE << order);
 		return 0;
 	}
 
+	ret = memcg_alloc_page_obj_cgroups(page, s, gfp);
+	if (ret)
+		return ret;
+
 	return memcg_charge_slab(page, gfp, order, s);
 }
 
@@ -527,6 +578,7 @@ static __always_inline void uncharge_slab_page(struct page *page, int order,
 		return;
 	}
 
+	memcg_free_page_obj_cgroups(page);
 	memcg_uncharge_slab(page, order, s);
 }
 
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 08/19] mm: memcg/slab: save obj_cgroup for non-root slab objects
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
                   ` (6 preceding siblings ...)
  2020-06-23  1:58 ` [PATCH v7 07/19] mm: memcg/slab: allocate obj_cgroups for non-root slab pages Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 09/19] mm: memcg/slab: charge individual slab objects instead of pages Roman Gushchin
                   ` (11 subsequent siblings)
  19 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

Store the obj_cgroup pointer in the corresponding place of
page->obj_cgroups for each allocated non-root slab object.  Make sure that
each allocated object holds a reference to obj_cgroup.

Objcg pointer is obtained from the memcg->objcg dereferencing in
memcg_kmem_get_cache() and passed from pre_alloc_hook to post_alloc_hook.
Then in case of successful allocation(s) it's getting stored in the
page->obj_cgroups vector.

The objcg obtaining part look a bit bulky now, but it will be simplified
by next commits in the series.

Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 include/linux/memcontrol.h |  3 +-
 mm/memcontrol.c            | 14 +++++++--
 mm/slab.c                  | 18 +++++++-----
 mm/slab.h                  | 60 ++++++++++++++++++++++++++++++++++----
 mm/slub.c                  | 14 +++++----
 5 files changed, 88 insertions(+), 21 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index f2f9d5d6b7d1..b845e908e76e 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1404,7 +1404,8 @@ static inline void memcg_set_shrinker_bit(struct mem_cgroup *memcg,
 }
 #endif
 
-struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep);
+struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep,
+					struct obj_cgroup **objcgp);
 void memcg_kmem_put_cache(struct kmem_cache *cachep);
 
 #ifdef CONFIG_MEMCG_KMEM
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 60e3f3ca75ca..5e55c7afc18c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2973,7 +2973,8 @@ static inline bool memcg_kmem_bypass(void)
  * done with it, memcg_kmem_put_cache() must be called to release the
  * reference.
  */
-struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep)
+struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep,
+					struct obj_cgroup **objcgp)
 {
 	struct mem_cgroup *memcg;
 	struct kmem_cache *memcg_cachep;
@@ -3029,8 +3030,17 @@ struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep)
 	 */
 	if (unlikely(!memcg_cachep))
 		memcg_schedule_kmem_cache_create(memcg, cachep);
-	else if (percpu_ref_tryget(&memcg_cachep->memcg_params.refcnt))
+	else if (percpu_ref_tryget(&memcg_cachep->memcg_params.refcnt)) {
+		struct obj_cgroup *objcg = rcu_dereference(memcg->objcg);
+
+		if (!objcg || !obj_cgroup_tryget(objcg)) {
+			percpu_ref_put(&memcg_cachep->memcg_params.refcnt);
+			goto out_unlock;
+		}
+
+		*objcgp = objcg;
 		cachep = memcg_cachep;
+	}
 out_unlock:
 	rcu_read_unlock();
 	return cachep;
diff --git a/mm/slab.c b/mm/slab.c
index 4c7013eeacd9..a7cc1336221f 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3222,9 +3222,10 @@ slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
 	unsigned long save_flags;
 	void *ptr;
 	int slab_node = numa_mem_id();
+	struct obj_cgroup *objcg = NULL;
 
 	flags &= gfp_allowed_mask;
-	cachep = slab_pre_alloc_hook(cachep, flags);
+	cachep = slab_pre_alloc_hook(cachep, &objcg, 1, flags);
 	if (unlikely(!cachep))
 		return NULL;
 
@@ -3260,7 +3261,7 @@ slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
 	if (unlikely(slab_want_init_on_alloc(flags, cachep)) && ptr)
 		memset(ptr, 0, cachep->object_size);
 
-	slab_post_alloc_hook(cachep, flags, 1, &ptr);
+	slab_post_alloc_hook(cachep, objcg, flags, 1, &ptr);
 	return ptr;
 }
 
@@ -3301,9 +3302,10 @@ slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller)
 {
 	unsigned long save_flags;
 	void *objp;
+	struct obj_cgroup *objcg = NULL;
 
 	flags &= gfp_allowed_mask;
-	cachep = slab_pre_alloc_hook(cachep, flags);
+	cachep = slab_pre_alloc_hook(cachep, &objcg, 1, flags);
 	if (unlikely(!cachep))
 		return NULL;
 
@@ -3317,7 +3319,7 @@ slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller)
 	if (unlikely(slab_want_init_on_alloc(flags, cachep)) && objp)
 		memset(objp, 0, cachep->object_size);
 
-	slab_post_alloc_hook(cachep, flags, 1, &objp);
+	slab_post_alloc_hook(cachep, objcg, flags, 1, &objp);
 	return objp;
 }
 
@@ -3443,6 +3445,7 @@ void ___cache_free(struct kmem_cache *cachep, void *objp,
 		memset(objp, 0, cachep->object_size);
 	kmemleak_free_recursive(objp, cachep->flags);
 	objp = cache_free_debugcheck(cachep, objp, caller);
+	memcg_slab_free_hook(cachep, virt_to_head_page(objp), objp);
 
 	/*
 	 * Skip calling cache_free_alien() when the platform is not numa.
@@ -3508,8 +3511,9 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
 			  void **p)
 {
 	size_t i;
+	struct obj_cgroup *objcg = NULL;
 
-	s = slab_pre_alloc_hook(s, flags);
+	s = slab_pre_alloc_hook(s, &objcg, size, flags);
 	if (!s)
 		return 0;
 
@@ -3532,13 +3536,13 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
 		for (i = 0; i < size; i++)
 			memset(p[i], 0, s->object_size);
 
-	slab_post_alloc_hook(s, flags, size, p);
+	slab_post_alloc_hook(s, objcg, flags, size, p);
 	/* FIXME: Trace call missing. Christoph would like a bulk variant */
 	return size;
 error:
 	local_irq_enable();
 	cache_alloc_debugcheck_after_bulk(s, flags, i, p, _RET_IP_);
-	slab_post_alloc_hook(s, flags, i, p);
+	slab_post_alloc_hook(s, objcg, flags, i, p);
 	__kmem_cache_free_bulk(s, i, p);
 	return 0;
 }
diff --git a/mm/slab.h b/mm/slab.h
index 7d175c2f1a61..c37a50f26e41 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -469,6 +469,41 @@ static inline void memcg_free_page_obj_cgroups(struct page *page)
 	page->obj_cgroups = NULL;
 }
 
+static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
+					      struct obj_cgroup *objcg,
+					      size_t size, void **p)
+{
+	struct page *page;
+	unsigned long off;
+	size_t i;
+
+	for (i = 0; i < size; i++) {
+		if (likely(p[i])) {
+			page = virt_to_head_page(p[i]);
+			off = obj_to_index(s, page, p[i]);
+			obj_cgroup_get(objcg);
+			page_obj_cgroups(page)[off] = objcg;
+		}
+	}
+	obj_cgroup_put(objcg);
+	memcg_kmem_put_cache(s);
+}
+
+static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page,
+					void *p)
+{
+	struct obj_cgroup *objcg;
+	unsigned int off;
+
+	if (!memcg_kmem_enabled() || is_root_cache(s))
+		return;
+
+	off = obj_to_index(s, page, p);
+	objcg = page_obj_cgroups(page)[off];
+	page_obj_cgroups(page)[off] = NULL;
+	obj_cgroup_put(objcg);
+}
+
 extern void slab_init_memcg_params(struct kmem_cache *);
 extern void memcg_link_cache(struct kmem_cache *s, struct mem_cgroup *memcg);
 
@@ -528,6 +563,17 @@ static inline void memcg_free_page_obj_cgroups(struct page *page)
 {
 }
 
+static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
+					      struct obj_cgroup *objcg,
+					      size_t size, void **p)
+{
+}
+
+static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page,
+					void *p)
+{
+}
+
 static inline void slab_init_memcg_params(struct kmem_cache *s)
 {
 }
@@ -630,7 +676,8 @@ static inline size_t slab_ksize(const struct kmem_cache *s)
 }
 
 static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
-						     gfp_t flags)
+						     struct obj_cgroup **objcgp,
+						     size_t size, gfp_t flags)
 {
 	flags &= gfp_allowed_mask;
 
@@ -644,13 +691,14 @@ static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
 
 	if (memcg_kmem_enabled() &&
 	    ((flags & __GFP_ACCOUNT) || (s->flags & SLAB_ACCOUNT)))
-		return memcg_kmem_get_cache(s);
+		return memcg_kmem_get_cache(s, objcgp);
 
 	return s;
 }
 
-static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
-					size_t size, void **p)
+static inline void slab_post_alloc_hook(struct kmem_cache *s,
+					struct obj_cgroup *objcg,
+					gfp_t flags, size_t size, void **p)
 {
 	size_t i;
 
@@ -662,8 +710,8 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
 					 s->flags, flags);
 	}
 
-	if (memcg_kmem_enabled())
-		memcg_kmem_put_cache(s);
+	if (memcg_kmem_enabled() && !is_root_cache(s))
+		memcg_slab_post_alloc_hook(s, objcg, size, p);
 }
 
 #ifndef CONFIG_SLOB
diff --git a/mm/slub.c b/mm/slub.c
index aa8d18824e62..25810980a26c 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2821,8 +2821,9 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s,
 	struct kmem_cache_cpu *c;
 	struct page *page;
 	unsigned long tid;
+	struct obj_cgroup *objcg = NULL;
 
-	s = slab_pre_alloc_hook(s, gfpflags);
+	s = slab_pre_alloc_hook(s, &objcg, 1, gfpflags);
 	if (!s)
 		return NULL;
 redo:
@@ -2898,7 +2899,7 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s,
 	if (unlikely(slab_want_init_on_alloc(gfpflags, s)) && object)
 		memset(object, 0, s->object_size);
 
-	slab_post_alloc_hook(s, gfpflags, 1, &object);
+	slab_post_alloc_hook(s, objcg, gfpflags, 1, &object);
 
 	return object;
 }
@@ -3103,6 +3104,8 @@ static __always_inline void do_slab_free(struct kmem_cache *s,
 	void *tail_obj = tail ? : head;
 	struct kmem_cache_cpu *c;
 	unsigned long tid;
+
+	memcg_slab_free_hook(s, page, head);
 redo:
 	/*
 	 * Determine the currently cpus per cpu slab.
@@ -3282,9 +3285,10 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
 {
 	struct kmem_cache_cpu *c;
 	int i;
+	struct obj_cgroup *objcg = NULL;
 
 	/* memcg and kmem_cache debug support */
-	s = slab_pre_alloc_hook(s, flags);
+	s = slab_pre_alloc_hook(s, &objcg, size, flags);
 	if (unlikely(!s))
 		return false;
 	/*
@@ -3338,11 +3342,11 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
 	}
 
 	/* memcg and kmem_cache debug support */
-	slab_post_alloc_hook(s, flags, size, p);
+	slab_post_alloc_hook(s, objcg, flags, size, p);
 	return i;
 error:
 	local_irq_enable();
-	slab_post_alloc_hook(s, flags, i, p);
+	slab_post_alloc_hook(s, objcg, flags, i, p);
 	__kmem_cache_free_bulk(s, i, p);
 	return 0;
 }
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 09/19] mm: memcg/slab: charge individual slab objects instead of pages
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
                   ` (7 preceding siblings ...)
  2020-06-23  1:58 ` [PATCH v7 08/19] mm: memcg/slab: save obj_cgroup for non-root slab objects Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  5:19   ` Shakeel Butt
  2020-06-23  1:58 ` [PATCH v7 10/19] mm: memcg/slab: deprecate memory.kmem.slabinfo Roman Gushchin
                   ` (10 subsequent siblings)
  19 siblings, 1 reply; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

Switch to per-object accounting of non-root slab objects.

Charging is performed using obj_cgroup API in the pre_alloc hook.
Obj_cgroup is charged with the size of the object and the size of
metadata: as now it's the size of an obj_cgroup pointer.  If the amount of
memory has been charged successfully, the actual allocation code is
executed.  Otherwise, -ENOMEM is returned.

In the post_alloc hook if the actual allocation succeeded, corresponding
vmstats are bumped and the obj_cgroup pointer is saved.  Otherwise, the
charge is canceled.

On the free path obj_cgroup pointer is obtained and used to uncharge the
size of the releasing object.

Memcg and lruvec counters are now representing only memory used by active
slab objects and do not include the free space.  The free space is shared
and doesn't belong to any specific cgroup.

Global per-node slab vmstats are still modified from
(un)charge_slab_page() functions.  The idea is to keep all slab pages
accounted as slab pages on system level.

Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slab.h | 173 ++++++++++++++++++++++++------------------------------
 1 file changed, 77 insertions(+), 96 deletions(-)

diff --git a/mm/slab.h b/mm/slab.h
index c37a50f26e41..09d2c659cb68 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -381,72 +381,6 @@ static inline struct mem_cgroup *memcg_from_slab_page(struct page *page)
 	return NULL;
 }
 
-/*
- * Charge the slab page belonging to the non-root kmem_cache.
- * Can be called for non-root kmem_caches only.
- */
-static __always_inline int memcg_charge_slab(struct page *page,
-					     gfp_t gfp, int order,
-					     struct kmem_cache *s)
-{
-	int nr_pages = 1 << order;
-	struct mem_cgroup *memcg;
-	struct lruvec *lruvec;
-	int ret;
-
-	rcu_read_lock();
-	memcg = READ_ONCE(s->memcg_params.memcg);
-	while (memcg && !css_tryget_online(&memcg->css))
-		memcg = parent_mem_cgroup(memcg);
-	rcu_read_unlock();
-
-	if (unlikely(!memcg || mem_cgroup_is_root(memcg))) {
-		mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
-				    nr_pages << PAGE_SHIFT);
-		percpu_ref_get_many(&s->memcg_params.refcnt, nr_pages);
-		return 0;
-	}
-
-	ret = memcg_kmem_charge(memcg, gfp, nr_pages);
-	if (ret)
-		goto out;
-
-	lruvec = mem_cgroup_lruvec(memcg, page_pgdat(page));
-	mod_lruvec_state(lruvec, cache_vmstat_idx(s), nr_pages << PAGE_SHIFT);
-
-	percpu_ref_get_many(&s->memcg_params.refcnt, nr_pages);
-out:
-	css_put(&memcg->css);
-	return ret;
-}
-
-/*
- * Uncharge a slab page belonging to a non-root kmem_cache.
- * Can be called for non-root kmem_caches only.
- */
-static __always_inline void memcg_uncharge_slab(struct page *page, int order,
-						struct kmem_cache *s)
-{
-	int nr_pages = 1 << order;
-	struct mem_cgroup *memcg;
-	struct lruvec *lruvec;
-
-	rcu_read_lock();
-	memcg = READ_ONCE(s->memcg_params.memcg);
-	if (likely(!mem_cgroup_is_root(memcg))) {
-		lruvec = mem_cgroup_lruvec(memcg, page_pgdat(page));
-		mod_lruvec_state(lruvec, cache_vmstat_idx(s),
-				 -(nr_pages << PAGE_SHIFT));
-		memcg_kmem_uncharge(memcg, nr_pages);
-	} else {
-		mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
-				    -(nr_pages << PAGE_SHIFT));
-	}
-	rcu_read_unlock();
-
-	percpu_ref_put_many(&s->memcg_params.refcnt, nr_pages);
-}
-
 static inline int memcg_alloc_page_obj_cgroups(struct page *page,
 					       struct kmem_cache *s, gfp_t gfp)
 {
@@ -469,6 +403,47 @@ static inline void memcg_free_page_obj_cgroups(struct page *page)
 	page->obj_cgroups = NULL;
 }
 
+static inline size_t obj_full_size(struct kmem_cache *s)
+{
+	/*
+	 * For each accounted object there is an extra space which is used
+	 * to store obj_cgroup membership. Charge it too.
+	 */
+	return s->size + sizeof(struct obj_cgroup *);
+}
+
+static inline struct kmem_cache *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
+						struct obj_cgroup **objcgp,
+						size_t objects, gfp_t flags)
+{
+	struct kmem_cache *cachep;
+
+	cachep = memcg_kmem_get_cache(s, objcgp);
+	if (is_root_cache(cachep))
+		return s;
+
+	if (obj_cgroup_charge(*objcgp, flags, objects * obj_full_size(s))) {
+		memcg_kmem_put_cache(cachep);
+		cachep = NULL;
+	}
+
+	return cachep;
+}
+
+static inline void mod_objcg_state(struct obj_cgroup *objcg,
+				   struct pglist_data *pgdat,
+				   int idx, int nr)
+{
+	struct mem_cgroup *memcg;
+	struct lruvec *lruvec;
+
+	rcu_read_lock();
+	memcg = obj_cgroup_memcg(objcg);
+	lruvec = mem_cgroup_lruvec(memcg, pgdat);
+	mod_memcg_lruvec_state(lruvec, idx, nr);
+	rcu_read_unlock();
+}
+
 static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
 					      struct obj_cgroup *objcg,
 					      size_t size, void **p)
@@ -483,6 +458,10 @@ static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
 			off = obj_to_index(s, page, p[i]);
 			obj_cgroup_get(objcg);
 			page_obj_cgroups(page)[off] = objcg;
+			mod_objcg_state(objcg, page_pgdat(page),
+					cache_vmstat_idx(s), obj_full_size(s));
+		} else {
+			obj_cgroup_uncharge(objcg, obj_full_size(s));
 		}
 	}
 	obj_cgroup_put(objcg);
@@ -501,6 +480,11 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page,
 	off = obj_to_index(s, page, p);
 	objcg = page_obj_cgroups(page)[off];
 	page_obj_cgroups(page)[off] = NULL;
+
+	obj_cgroup_uncharge(objcg, obj_full_size(s));
+	mod_objcg_state(objcg, page_pgdat(page), cache_vmstat_idx(s),
+			-obj_full_size(s));
+
 	obj_cgroup_put(objcg);
 }
 
@@ -542,17 +526,6 @@ static inline struct mem_cgroup *memcg_from_slab_page(struct page *page)
 	return NULL;
 }
 
-static inline int memcg_charge_slab(struct page *page, gfp_t gfp, int order,
-				    struct kmem_cache *s)
-{
-	return 0;
-}
-
-static inline void memcg_uncharge_slab(struct page *page, int order,
-				       struct kmem_cache *s)
-{
-}
-
 static inline int memcg_alloc_page_obj_cgroups(struct page *page,
 					       struct kmem_cache *s, gfp_t gfp)
 {
@@ -563,6 +536,13 @@ static inline void memcg_free_page_obj_cgroups(struct page *page)
 {
 }
 
+static inline struct kmem_cache *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
+						struct obj_cgroup **objcgp,
+						size_t objects, gfp_t flags)
+{
+	return NULL;
+}
+
 static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
 					      struct obj_cgroup *objcg,
 					      size_t size, void **p)
@@ -600,32 +580,33 @@ static __always_inline int charge_slab_page(struct page *page,
 					    gfp_t gfp, int order,
 					    struct kmem_cache *s)
 {
-	int ret;
-
-	if (is_root_cache(s)) {
-		mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
-				    PAGE_SIZE << order);
-		return 0;
-	}
+#ifdef CONFIG_MEMCG_KMEM
+	if (memcg_kmem_enabled() && !is_root_cache(s)) {
+		int ret;
 
-	ret = memcg_alloc_page_obj_cgroups(page, s, gfp);
-	if (ret)
-		return ret;
+		ret = memcg_alloc_page_obj_cgroups(page, s, gfp);
+		if (ret)
+			return ret;
 
-	return memcg_charge_slab(page, gfp, order, s);
+		percpu_ref_get_many(&s->memcg_params.refcnt, 1 << order);
+	}
+#endif
+	mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
+			    PAGE_SIZE << order);
+	return 0;
 }
 
 static __always_inline void uncharge_slab_page(struct page *page, int order,
 					       struct kmem_cache *s)
 {
-	if (is_root_cache(s)) {
-		mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
-				    -(PAGE_SIZE << order));
-		return;
+#ifdef CONFIG_MEMCG_KMEM
+	if (memcg_kmem_enabled() && !is_root_cache(s)) {
+		memcg_free_page_obj_cgroups(page);
+		percpu_ref_put_many(&s->memcg_params.refcnt, 1 << order);
 	}
-
-	memcg_free_page_obj_cgroups(page);
-	memcg_uncharge_slab(page, order, s);
+#endif
+	mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
+			    -(PAGE_SIZE << order));
 }
 
 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
@@ -691,7 +672,7 @@ static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
 
 	if (memcg_kmem_enabled() &&
 	    ((flags & __GFP_ACCOUNT) || (s->flags & SLAB_ACCOUNT)))
-		return memcg_kmem_get_cache(s, objcgp);
+		return memcg_slab_pre_alloc_hook(s, objcgp, size, flags);
 
 	return s;
 }
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 10/19] mm: memcg/slab: deprecate memory.kmem.slabinfo
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
                   ` (8 preceding siblings ...)
  2020-06-23  1:58 ` [PATCH v7 09/19] mm: memcg/slab: charge individual slab objects instead of pages Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 11/19] mm: memcg/slab: move memcg_kmem_bypass() to memcontrol.h Roman Gushchin
                   ` (9 subsequent siblings)
  19 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

Deprecate memory.kmem.slabinfo.

An empty file will be presented if corresponding config options are
enabled.

The interface is implementation dependent, isn't present in cgroup v2, and
is generally useful only for core mm debugging purposes.  In other words,
it doesn't provide any value for the absolute majority of users.

A drgn-based replacement can be found in tools/cgroup/slabinfo.py .  It
does support cgroup v1 and v2, mimics memory.kmem.slabinfo output and also
allows to get any additional information without a need to recompile the
kernel.

If a drgn-based solution is too slow for a task, a bpf-based tracing tool
can be used, which can easily keep track of all slab allocations belonging
to a memory cgroup.

Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 mm/memcontrol.c  |  3 ---
 mm/slab_common.c | 31 ++++---------------------------
 2 files changed, 4 insertions(+), 30 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 5e55c7afc18c..ad43e5bc482b 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5118,9 +5118,6 @@ static struct cftype mem_cgroup_legacy_files[] = {
 	(defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG))
 	{
 		.name = "kmem.slabinfo",
-		.seq_start = memcg_slab_start,
-		.seq_next = memcg_slab_next,
-		.seq_stop = memcg_slab_stop,
 		.seq_show = memcg_slab_show,
 	},
 #endif
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 4fb76b45ce23..42edfa46fee6 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1523,35 +1523,12 @@ void dump_unreclaimable_slab(void)
 }
 
 #if defined(CONFIG_MEMCG_KMEM)
-void *memcg_slab_start(struct seq_file *m, loff_t *pos)
-{
-	struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
-
-	mutex_lock(&slab_mutex);
-	return seq_list_start(&memcg->kmem_caches, *pos);
-}
-
-void *memcg_slab_next(struct seq_file *m, void *p, loff_t *pos)
-{
-	struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
-
-	return seq_list_next(p, &memcg->kmem_caches, pos);
-}
-
-void memcg_slab_stop(struct seq_file *m, void *p)
-{
-	mutex_unlock(&slab_mutex);
-}
-
 int memcg_slab_show(struct seq_file *m, void *p)
 {
-	struct kmem_cache *s = list_entry(p, struct kmem_cache,
-					  memcg_params.kmem_caches_node);
-	struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
-
-	if (p == memcg->kmem_caches.next)
-		print_slabinfo_header(m);
-	cache_show(s, m);
+	/*
+	 * Deprecated.
+	 * Please, take a look at tools/cgroup/slabinfo.py .
+	 */
 	return 0;
 }
 #endif
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 11/19] mm: memcg/slab: move memcg_kmem_bypass() to memcontrol.h
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
                   ` (9 preceding siblings ...)
  2020-06-23  1:58 ` [PATCH v7 10/19] mm: memcg/slab: deprecate memory.kmem.slabinfo Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 12/19] mm: memcg/slab: use a single set of kmem_caches for all accounted allocations Roman Gushchin
                   ` (8 subsequent siblings)
  19 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

To make the memcg_kmem_bypass() function available outside of the
memcontrol.c, let's move it to memcontrol.h.  The function is small and
nicely fits into static inline sort of functions.

It will be used from the slab code.

Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 include/linux/memcontrol.h | 12 ++++++++++++
 mm/memcontrol.c            | 12 ------------
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index b845e908e76e..83e2858aecf2 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1440,6 +1440,18 @@ static inline bool memcg_kmem_enabled(void)
 	return static_branch_unlikely(&memcg_kmem_enabled_key);
 }
 
+static inline bool memcg_kmem_bypass(void)
+{
+	if (in_interrupt())
+		return true;
+
+	/* Allow remote memcg charging in kthread contexts. */
+	if ((!current->mm || (current->flags & PF_KTHREAD)) &&
+	     !current->active_memcg)
+		return true;
+	return false;
+}
+
 static inline int memcg_kmem_charge_page(struct page *page, gfp_t gfp,
 					 int order)
 {
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ad43e5bc482b..2ad1ff0f0107 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2945,18 +2945,6 @@ static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
 	queue_work(memcg_kmem_cache_wq, &cw->work);
 }
 
-static inline bool memcg_kmem_bypass(void)
-{
-	if (in_interrupt())
-		return true;
-
-	/* Allow remote memcg charging in kthread contexts. */
-	if ((!current->mm || (current->flags & PF_KTHREAD)) &&
-	     !current->active_memcg)
-		return true;
-	return false;
-}
-
 /**
  * memcg_kmem_get_cache: select the correct per-memcg cache for allocation
  * @cachep: the original global kmem cache
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 12/19] mm: memcg/slab: use a single set of kmem_caches for all accounted allocations
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
                   ` (10 preceding siblings ...)
  2020-06-23  1:58 ` [PATCH v7 11/19] mm: memcg/slab: move memcg_kmem_bypass() to memcontrol.h Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 13/19] mm: memcg/slab: simplify memcg cache creation Roman Gushchin
                   ` (7 subsequent siblings)
  19 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

This is fairly big but mostly red patch, which makes all accounted slab
allocations use a single set of kmem_caches instead of creating a separate
set for each memory cgroup.

Because the number of non-root kmem_caches is now capped by the number of
root kmem_caches, there is no need to shrink or destroy them prematurely.
They can be perfectly destroyed together with their root counterparts.
This allows to dramatically simplify the management of non-root
kmem_caches and delete a ton of code.

This patch performs the following changes:
1) introduces memcg_params.memcg_cache pointer to represent the
   kmem_cache which will be used for all non-root allocations
2) reuses the existing memcg kmem_cache creation mechanism
   to create memcg kmem_cache on the first allocation attempt
3) memcg kmem_caches are named <kmemcache_name>-memcg,
   e.g. dentry-memcg
4) simplifies memcg_kmem_get_cache() to just return memcg kmem_cache
   or schedule it's creation and return the root cache
5) removes almost all non-root kmem_cache management code
   (separate refcounter, reparenting, shrinking, etc)
6) makes slab debugfs to display root_mem_cgroup css id and never
   show :dead and :deact flags in the memcg_slabinfo attribute.

Following patches in the series will simplify the kmem_cache creation.

Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 include/linux/memcontrol.h |   5 +-
 include/linux/slab.h       |   5 +-
 mm/memcontrol.c            | 167 +++------------
 mm/slab.c                  |  16 +-
 mm/slab.h                  | 145 ++++---------
 mm/slab_common.c           | 426 ++++---------------------------------
 mm/slub.c                  |  38 +---
 7 files changed, 129 insertions(+), 673 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 83e2858aecf2..11fd18b3d6c6 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -317,7 +317,6 @@ struct mem_cgroup {
         /* Index in the kmem_cache->memcg_params.memcg_caches array */
 	int kmemcg_id;
 	enum memcg_kmem_state kmem_state;
-	struct list_head kmem_caches;
 	struct obj_cgroup __rcu *objcg;
 	struct list_head objcg_list; /* list of inherited objcgs */
 #endif
@@ -1404,9 +1403,7 @@ static inline void memcg_set_shrinker_bit(struct mem_cgroup *memcg,
 }
 #endif
 
-struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep,
-					struct obj_cgroup **objcgp);
-void memcg_kmem_put_cache(struct kmem_cache *cachep);
+struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep);
 
 #ifdef CONFIG_MEMCG_KMEM
 int __memcg_kmem_charge(struct mem_cgroup *memcg, gfp_t gfp,
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 0884d82c55ee..8b1f91e320f9 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -155,8 +155,7 @@ struct kmem_cache *kmem_cache_create_usercopy(const char *name,
 void kmem_cache_destroy(struct kmem_cache *);
 int kmem_cache_shrink(struct kmem_cache *);
 
-void memcg_create_kmem_cache(struct mem_cgroup *, struct kmem_cache *);
-void memcg_deactivate_kmem_caches(struct mem_cgroup *, struct mem_cgroup *);
+void memcg_create_kmem_cache(struct kmem_cache *cachep);
 
 /*
  * Please use this macro to create slab caches. Simply specify the
@@ -580,8 +579,6 @@ static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 	return __kmalloc_node(size, flags, node);
 }
 
-int memcg_update_all_caches(int num_memcgs);
-
 /**
  * kmalloc_array - allocate memory for an array.
  * @n: number of elements.
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2ad1ff0f0107..417070fb0fd0 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -350,7 +350,7 @@ static void memcg_reparent_objcgs(struct mem_cgroup *memcg,
 }
 
 /*
- * This will be the memcg's index in each cache's ->memcg_params.memcg_caches.
+ * This will be used as a shrinker list's index.
  * The main reason for not using cgroup id for this:
  *  this works better in sparse environments, where we have a lot of memcgs,
  *  but only a few kmem-limited. Or also, if we have, for instance, 200
@@ -569,20 +569,16 @@ ino_t page_cgroup_ino(struct page *page)
 	unsigned long ino = 0;
 
 	rcu_read_lock();
-	if (PageSlab(page) && !PageTail(page)) {
-		memcg = memcg_from_slab_page(page);
-	} else {
-		memcg = page->mem_cgroup;
+	memcg = page->mem_cgroup;
 
-		/*
-		 * The lowest bit set means that memcg isn't a valid
-		 * memcg pointer, but a obj_cgroups pointer.
-		 * In this case the page is shared and doesn't belong
-		 * to any specific memory cgroup.
-		 */
-		if ((unsigned long) memcg & 0x1UL)
-			memcg = NULL;
-	}
+	/*
+	 * The lowest bit set means that memcg isn't a valid
+	 * memcg pointer, but a obj_cgroups pointer.
+	 * In this case the page is shared and doesn't belong
+	 * to any specific memory cgroup.
+	 */
+	if ((unsigned long) memcg & 0x1UL)
+		memcg = NULL;
 
 	while (memcg && !(memcg->css.flags & CSS_ONLINE))
 		memcg = parent_mem_cgroup(memcg);
@@ -2822,12 +2818,18 @@ struct mem_cgroup *mem_cgroup_from_obj(void *p)
 	page = virt_to_head_page(p);
 
 	/*
-	 * Slab pages don't have page->mem_cgroup set because corresponding
-	 * kmem caches can be reparented during the lifetime. That's why
-	 * memcg_from_slab_page() should be used instead.
+	 * Slab objects are accounted individually, not per-page.
+	 * Memcg membership data for each individual object is saved in
+	 * the page->obj_cgroups.
 	 */
-	if (PageSlab(page))
-		return memcg_from_slab_page(page);
+	if (page_has_obj_cgroups(page)) {
+		struct obj_cgroup *objcg;
+		unsigned int off;
+
+		off = obj_to_index(page->slab_cache, page, p);
+		objcg = page_obj_cgroups(page)[off];
+		return obj_cgroup_memcg(objcg);
+	}
 
 	/* All other pages use page->mem_cgroup */
 	return page->mem_cgroup;
@@ -2882,9 +2884,7 @@ static int memcg_alloc_cache_id(void)
 	else if (size > MEMCG_CACHES_MAX_SIZE)
 		size = MEMCG_CACHES_MAX_SIZE;
 
-	err = memcg_update_all_caches(size);
-	if (!err)
-		err = memcg_update_all_list_lrus(size);
+	err = memcg_update_all_list_lrus(size);
 	if (!err)
 		memcg_nr_cache_ids = size;
 
@@ -2903,7 +2903,6 @@ static void memcg_free_cache_id(int id)
 }
 
 struct memcg_kmem_cache_create_work {
-	struct mem_cgroup *memcg;
 	struct kmem_cache *cachep;
 	struct work_struct work;
 };
@@ -2912,33 +2911,24 @@ static void memcg_kmem_cache_create_func(struct work_struct *w)
 {
 	struct memcg_kmem_cache_create_work *cw =
 		container_of(w, struct memcg_kmem_cache_create_work, work);
-	struct mem_cgroup *memcg = cw->memcg;
 	struct kmem_cache *cachep = cw->cachep;
 
-	memcg_create_kmem_cache(memcg, cachep);
+	memcg_create_kmem_cache(cachep);
 
-	css_put(&memcg->css);
 	kfree(cw);
 }
 
 /*
  * Enqueue the creation of a per-memcg kmem_cache.
  */
-static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
-					       struct kmem_cache *cachep)
+static void memcg_schedule_kmem_cache_create(struct kmem_cache *cachep)
 {
 	struct memcg_kmem_cache_create_work *cw;
 
-	if (!css_tryget_online(&memcg->css))
-		return;
-
 	cw = kmalloc(sizeof(*cw), GFP_NOWAIT | __GFP_NOWARN);
-	if (!cw) {
-		css_put(&memcg->css);
+	if (!cw)
 		return;
-	}
 
-	cw->memcg = memcg;
 	cw->cachep = cachep;
 	INIT_WORK(&cw->work, memcg_kmem_cache_create_func);
 
@@ -2946,102 +2936,26 @@ static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
 }
 
 /**
- * memcg_kmem_get_cache: select the correct per-memcg cache for allocation
+ * memcg_kmem_get_cache: select memcg or root cache for allocation
  * @cachep: the original global kmem cache
  *
  * Return the kmem_cache we're supposed to use for a slab allocation.
- * We try to use the current memcg's version of the cache.
  *
  * If the cache does not exist yet, if we are the first user of it, we
  * create it asynchronously in a workqueue and let the current allocation
  * go through with the original cache.
- *
- * This function takes a reference to the cache it returns to assure it
- * won't get destroyed while we are working with it. Once the caller is
- * done with it, memcg_kmem_put_cache() must be called to release the
- * reference.
  */
-struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep,
-					struct obj_cgroup **objcgp)
+struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep)
 {
-	struct mem_cgroup *memcg;
 	struct kmem_cache *memcg_cachep;
-	struct memcg_cache_array *arr;
-	int kmemcg_id;
 
-	VM_BUG_ON(!is_root_cache(cachep));
-
-	if (memcg_kmem_bypass())
+	memcg_cachep = READ_ONCE(cachep->memcg_params.memcg_cache);
+	if (unlikely(!memcg_cachep)) {
+		memcg_schedule_kmem_cache_create(cachep);
 		return cachep;
-
-	rcu_read_lock();
-
-	if (unlikely(current->active_memcg))
-		memcg = current->active_memcg;
-	else
-		memcg = mem_cgroup_from_task(current);
-
-	if (!memcg || memcg == root_mem_cgroup)
-		goto out_unlock;
-
-	kmemcg_id = READ_ONCE(memcg->kmemcg_id);
-	if (kmemcg_id < 0)
-		goto out_unlock;
-
-	arr = rcu_dereference(cachep->memcg_params.memcg_caches);
-
-	/*
-	 * Make sure we will access the up-to-date value. The code updating
-	 * memcg_caches issues a write barrier to match the data dependency
-	 * barrier inside READ_ONCE() (see memcg_create_kmem_cache()).
-	 */
-	memcg_cachep = READ_ONCE(arr->entries[kmemcg_id]);
-
-	/*
-	 * If we are in a safe context (can wait, and not in interrupt
-	 * context), we could be be predictable and return right away.
-	 * This would guarantee that the allocation being performed
-	 * already belongs in the new cache.
-	 *
-	 * However, there are some clashes that can arrive from locking.
-	 * For instance, because we acquire the slab_mutex while doing
-	 * memcg_create_kmem_cache, this means no further allocation
-	 * could happen with the slab_mutex held. So it's better to
-	 * defer everything.
-	 *
-	 * If the memcg is dying or memcg_cache is about to be released,
-	 * don't bother creating new kmem_caches. Because memcg_cachep
-	 * is ZEROed as the fist step of kmem offlining, we don't need
-	 * percpu_ref_tryget_live() here. css_tryget_online() check in
-	 * memcg_schedule_kmem_cache_create() will prevent us from
-	 * creation of a new kmem_cache.
-	 */
-	if (unlikely(!memcg_cachep))
-		memcg_schedule_kmem_cache_create(memcg, cachep);
-	else if (percpu_ref_tryget(&memcg_cachep->memcg_params.refcnt)) {
-		struct obj_cgroup *objcg = rcu_dereference(memcg->objcg);
-
-		if (!objcg || !obj_cgroup_tryget(objcg)) {
-			percpu_ref_put(&memcg_cachep->memcg_params.refcnt);
-			goto out_unlock;
-		}
-
-		*objcgp = objcg;
-		cachep = memcg_cachep;
 	}
-out_unlock:
-	rcu_read_unlock();
-	return cachep;
-}
 
-/**
- * memcg_kmem_put_cache: drop reference taken by memcg_kmem_get_cache
- * @cachep: the cache returned by memcg_kmem_get_cache
- */
-void memcg_kmem_put_cache(struct kmem_cache *cachep)
-{
-	if (!is_root_cache(cachep))
-		percpu_ref_put(&cachep->memcg_params.refcnt);
+	return memcg_cachep;
 }
 
 /**
@@ -3730,7 +3644,6 @@ static int memcg_online_kmem(struct mem_cgroup *memcg)
 	 */
 	memcg->kmemcg_id = memcg_id;
 	memcg->kmem_state = KMEM_ONLINE;
-	INIT_LIST_HEAD(&memcg->kmem_caches);
 
 	return 0;
 }
@@ -3743,22 +3656,13 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg)
 
 	if (memcg->kmem_state != KMEM_ONLINE)
 		return;
-	/*
-	 * Clear the online state before clearing memcg_caches array
-	 * entries. The slab_mutex in memcg_deactivate_kmem_caches()
-	 * guarantees that no cache will be created for this cgroup
-	 * after we are done (see memcg_create_kmem_cache()).
-	 */
+
 	memcg->kmem_state = KMEM_ALLOCATED;
 
 	parent = parent_mem_cgroup(memcg);
 	if (!parent)
 		parent = root_mem_cgroup;
 
-	/*
-	 * Deactivate and reparent kmem_caches and objcgs.
-	 */
-	memcg_deactivate_kmem_caches(memcg, parent);
 	memcg_reparent_objcgs(memcg, parent);
 
 	kmemcg_id = memcg->kmemcg_id;
@@ -3793,10 +3697,8 @@ static void memcg_free_kmem(struct mem_cgroup *memcg)
 	if (unlikely(memcg->kmem_state == KMEM_ONLINE))
 		memcg_offline_kmem(memcg);
 
-	if (memcg->kmem_state == KMEM_ALLOCATED) {
-		WARN_ON(!list_empty(&memcg->kmem_caches));
+	if (memcg->kmem_state == KMEM_ALLOCATED)
 		static_branch_dec(&memcg_kmem_enabled_key);
-	}
 }
 #else
 static int memcg_online_kmem(struct mem_cgroup *memcg)
@@ -5388,9 +5290,6 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
 
 	/* The following stuff does not apply to the root */
 	if (!parent) {
-#ifdef CONFIG_MEMCG_KMEM
-		INIT_LIST_HEAD(&memcg->kmem_caches);
-#endif
 		root_mem_cgroup = memcg;
 		return &memcg->css;
 	}
diff --git a/mm/slab.c b/mm/slab.c
index a7cc1336221f..84e218fd0bcf 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1239,7 +1239,7 @@ void __init kmem_cache_init(void)
 				  nr_node_ids * sizeof(struct kmem_cache_node *),
 				  SLAB_HWCACHE_ALIGN, 0, 0);
 	list_add(&kmem_cache->list, &slab_caches);
-	memcg_link_cache(kmem_cache, NULL);
+	memcg_link_cache(kmem_cache);
 	slab_state = PARTIAL;
 
 	/*
@@ -2243,17 +2243,6 @@ int __kmem_cache_shrink(struct kmem_cache *cachep)
 	return (ret ? 1 : 0);
 }
 
-#ifdef CONFIG_MEMCG
-void __kmemcg_cache_deactivate(struct kmem_cache *cachep)
-{
-	__kmem_cache_shrink(cachep);
-}
-
-void __kmemcg_cache_deactivate_after_rcu(struct kmem_cache *s)
-{
-}
-#endif
-
 int __kmem_cache_shutdown(struct kmem_cache *cachep)
 {
 	return __kmem_cache_shrink(cachep);
@@ -3865,7 +3854,8 @@ static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
 		return ret;
 
 	lockdep_assert_held(&slab_mutex);
-	for_each_memcg_cache(c, cachep) {
+	c = memcg_cache(cachep);
+	if (c) {
 		/* return value determined by the root cache only */
 		__do_tune_cpucache(c, limit, batchcount, shared, gfp);
 	}
diff --git a/mm/slab.h b/mm/slab.h
index 09d2c659cb68..673448e5cfb3 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -32,66 +32,25 @@ struct kmem_cache {
 
 #else /* !CONFIG_SLOB */
 
-struct memcg_cache_array {
-	struct rcu_head rcu;
-	struct kmem_cache *entries[0];
-};
-
 /*
  * This is the main placeholder for memcg-related information in kmem caches.
- * Both the root cache and the child caches will have it. For the root cache,
- * this will hold a dynamically allocated array large enough to hold
- * information about the currently limited memcgs in the system. To allow the
- * array to be accessed without taking any locks, on relocation we free the old
- * version only after a grace period.
- *
- * Root and child caches hold different metadata.
+ * Both the root cache and the child cache will have it. Some fields are used
+ * in both cases, other are specific to root caches.
  *
  * @root_cache:	Common to root and child caches.  NULL for root, pointer to
  *		the root cache for children.
  *
  * The following fields are specific to root caches.
  *
- * @memcg_caches: kmemcg ID indexed table of child caches.  This table is
- *		used to index child cachces during allocation and cleared
- *		early during shutdown.
- *
- * @root_caches_node: List node for slab_root_caches list.
- *
- * @children:	List of all child caches.  While the child caches are also
- *		reachable through @memcg_caches, a child cache remains on
- *		this list until it is actually destroyed.
- *
- * The following fields are specific to child caches.
- *
- * @memcg:	Pointer to the memcg this cache belongs to.
- *
- * @children_node: List node for @root_cache->children list.
- *
- * @kmem_caches_node: List node for @memcg->kmem_caches list.
+ * @memcg_cache: pointer to memcg kmem cache, used by all non-root memory
+ *		cgroups.
+ * @root_caches_node: list node for slab_root_caches list.
  */
 struct memcg_cache_params {
 	struct kmem_cache *root_cache;
-	union {
-		struct {
-			struct memcg_cache_array __rcu *memcg_caches;
-			struct list_head __root_caches_node;
-			struct list_head children;
-			bool dying;
-		};
-		struct {
-			struct mem_cgroup *memcg;
-			struct list_head children_node;
-			struct list_head kmem_caches_node;
-			struct percpu_ref refcnt;
-
-			void (*work_fn)(struct kmem_cache *);
-			union {
-				struct rcu_head rcu_head;
-				struct work_struct work;
-			};
-		};
-	};
+
+	struct kmem_cache *memcg_cache;
+	struct list_head __root_caches_node;
 };
 #endif /* CONFIG_SLOB */
 
@@ -235,8 +194,6 @@ bool __kmem_cache_empty(struct kmem_cache *);
 int __kmem_cache_shutdown(struct kmem_cache *);
 void __kmem_cache_release(struct kmem_cache *);
 int __kmem_cache_shrink(struct kmem_cache *);
-void __kmemcg_cache_deactivate(struct kmem_cache *s);
-void __kmemcg_cache_deactivate_after_rcu(struct kmem_cache *s);
 void slab_kmem_cache_release(struct kmem_cache *);
 void kmem_cache_shrink_all(struct kmem_cache *s);
 
@@ -310,14 +267,6 @@ static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t fla
 extern struct list_head		slab_root_caches;
 #define root_caches_node	memcg_params.__root_caches_node
 
-/*
- * Iterate over all memcg caches of the given root cache. The caller must hold
- * slab_mutex.
- */
-#define for_each_memcg_cache(iter, root) \
-	list_for_each_entry(iter, &(root)->memcg_params.children, \
-			    memcg_params.children_node)
-
 static inline bool is_root_cache(struct kmem_cache *s)
 {
 	return !s->memcg_params.root_cache;
@@ -348,6 +297,13 @@ static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 	return s->memcg_params.root_cache;
 }
 
+static inline struct kmem_cache *memcg_cache(struct kmem_cache *s)
+{
+	if (is_root_cache(s))
+		return s->memcg_params.memcg_cache;
+	return NULL;
+}
+
 static inline struct obj_cgroup **page_obj_cgroups(struct page *page)
 {
 	/*
@@ -360,25 +316,9 @@ static inline struct obj_cgroup **page_obj_cgroups(struct page *page)
 		((unsigned long)page->obj_cgroups & ~0x1UL);
 }
 
-/*
- * Expects a pointer to a slab page. Please note, that PageSlab() check
- * isn't sufficient, as it returns true also for tail compound slab pages,
- * which do not have slab_cache pointer set.
- * So this function assumes that the page can pass PageSlab() && !PageTail()
- * check.
- *
- * The kmem_cache can be reparented asynchronously. The caller must ensure
- * the memcg lifetime, e.g. by taking rcu_read_lock() or cgroup_mutex.
- */
-static inline struct mem_cgroup *memcg_from_slab_page(struct page *page)
+static inline bool page_has_obj_cgroups(struct page *page)
 {
-	struct kmem_cache *s;
-
-	s = READ_ONCE(page->slab_cache);
-	if (s && !is_root_cache(s))
-		return READ_ONCE(s->memcg_params.memcg);
-
-	return NULL;
+	return ((unsigned long)page->obj_cgroups & 0x1UL);
 }
 
 static inline int memcg_alloc_page_obj_cgroups(struct page *page,
@@ -417,16 +357,25 @@ static inline struct kmem_cache *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
 						size_t objects, gfp_t flags)
 {
 	struct kmem_cache *cachep;
+	struct obj_cgroup *objcg;
+
+	if (memcg_kmem_bypass())
+		return s;
 
-	cachep = memcg_kmem_get_cache(s, objcgp);
+	cachep = memcg_kmem_get_cache(s);
 	if (is_root_cache(cachep))
 		return s;
 
-	if (obj_cgroup_charge(*objcgp, flags, objects * obj_full_size(s))) {
-		memcg_kmem_put_cache(cachep);
+	objcg = get_obj_cgroup_from_current();
+	if (!objcg)
+		return s;
+
+	if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s))) {
+		obj_cgroup_put(objcg);
 		cachep = NULL;
 	}
 
+	*objcgp = objcg;
 	return cachep;
 }
 
@@ -465,7 +414,6 @@ static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
 		}
 	}
 	obj_cgroup_put(objcg);
-	memcg_kmem_put_cache(s);
 }
 
 static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page,
@@ -489,7 +437,7 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page,
 }
 
 extern void slab_init_memcg_params(struct kmem_cache *);
-extern void memcg_link_cache(struct kmem_cache *s, struct mem_cgroup *memcg);
+extern void memcg_link_cache(struct kmem_cache *s);
 
 #else /* CONFIG_MEMCG_KMEM */
 
@@ -497,9 +445,6 @@ extern void memcg_link_cache(struct kmem_cache *s, struct mem_cgroup *memcg);
 #define slab_root_caches	slab_caches
 #define root_caches_node	list
 
-#define for_each_memcg_cache(iter, root) \
-	for ((void)(iter), (void)(root); 0; )
-
 static inline bool is_root_cache(struct kmem_cache *s)
 {
 	return true;
@@ -521,7 +466,17 @@ static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 	return s;
 }
 
-static inline struct mem_cgroup *memcg_from_slab_page(struct page *page)
+static inline struct kmem_cache *memcg_cache(struct kmem_cache *s)
+{
+	return NULL;
+}
+
+static inline bool page_has_obj_cgroups(struct page *page)
+{
+	return false;
+}
+
+static inline struct mem_cgroup *memcg_from_slab_obj(void *ptr)
 {
 	return NULL;
 }
@@ -558,8 +513,7 @@ static inline void slab_init_memcg_params(struct kmem_cache *s)
 {
 }
 
-static inline void memcg_link_cache(struct kmem_cache *s,
-				    struct mem_cgroup *memcg)
+static inline void memcg_link_cache(struct kmem_cache *s)
 {
 }
 
@@ -580,17 +534,14 @@ static __always_inline int charge_slab_page(struct page *page,
 					    gfp_t gfp, int order,
 					    struct kmem_cache *s)
 {
-#ifdef CONFIG_MEMCG_KMEM
 	if (memcg_kmem_enabled() && !is_root_cache(s)) {
 		int ret;
 
 		ret = memcg_alloc_page_obj_cgroups(page, s, gfp);
 		if (ret)
 			return ret;
-
-		percpu_ref_get_many(&s->memcg_params.refcnt, 1 << order);
 	}
-#endif
+
 	mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
 			    PAGE_SIZE << order);
 	return 0;
@@ -599,12 +550,9 @@ static __always_inline int charge_slab_page(struct page *page,
 static __always_inline void uncharge_slab_page(struct page *page, int order,
 					       struct kmem_cache *s)
 {
-#ifdef CONFIG_MEMCG_KMEM
-	if (memcg_kmem_enabled() && !is_root_cache(s)) {
+	if (memcg_kmem_enabled() && !is_root_cache(s))
 		memcg_free_page_obj_cgroups(page);
-		percpu_ref_put_many(&s->memcg_params.refcnt, 1 << order);
-	}
-#endif
+
 	mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
 			    -(PAGE_SIZE << order));
 }
@@ -747,9 +695,6 @@ static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
 void *slab_start(struct seq_file *m, loff_t *pos);
 void *slab_next(struct seq_file *m, void *p, loff_t *pos);
 void slab_stop(struct seq_file *m, void *p);
-void *memcg_slab_start(struct seq_file *m, loff_t *pos);
-void *memcg_slab_next(struct seq_file *m, void *p, loff_t *pos);
-void memcg_slab_stop(struct seq_file *m, void *p);
 int memcg_slab_show(struct seq_file *m, void *p);
 
 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 42edfa46fee6..90c25c8db1a5 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -131,141 +131,36 @@ int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr,
 #ifdef CONFIG_MEMCG_KMEM
 
 LIST_HEAD(slab_root_caches);
-static DEFINE_SPINLOCK(memcg_kmem_wq_lock);
-
-static void kmemcg_cache_shutdown(struct percpu_ref *percpu_ref);
 
 void slab_init_memcg_params(struct kmem_cache *s)
 {
 	s->memcg_params.root_cache = NULL;
-	RCU_INIT_POINTER(s->memcg_params.memcg_caches, NULL);
-	INIT_LIST_HEAD(&s->memcg_params.children);
-	s->memcg_params.dying = false;
+	s->memcg_params.memcg_cache = NULL;
 }
 
-static int init_memcg_params(struct kmem_cache *s,
-			     struct kmem_cache *root_cache)
+static void init_memcg_params(struct kmem_cache *s,
+			      struct kmem_cache *root_cache)
 {
-	struct memcg_cache_array *arr;
-
-	if (root_cache) {
-		int ret = percpu_ref_init(&s->memcg_params.refcnt,
-					  kmemcg_cache_shutdown,
-					  0, GFP_KERNEL);
-		if (ret)
-			return ret;
-
+	if (root_cache)
 		s->memcg_params.root_cache = root_cache;
-		INIT_LIST_HEAD(&s->memcg_params.children_node);
-		INIT_LIST_HEAD(&s->memcg_params.kmem_caches_node);
-		return 0;
-	}
-
-	slab_init_memcg_params(s);
-
-	if (!memcg_nr_cache_ids)
-		return 0;
-
-	arr = kvzalloc(sizeof(struct memcg_cache_array) +
-		       memcg_nr_cache_ids * sizeof(void *),
-		       GFP_KERNEL);
-	if (!arr)
-		return -ENOMEM;
-
-	RCU_INIT_POINTER(s->memcg_params.memcg_caches, arr);
-	return 0;
-}
-
-static void destroy_memcg_params(struct kmem_cache *s)
-{
-	if (is_root_cache(s)) {
-		kvfree(rcu_access_pointer(s->memcg_params.memcg_caches));
-	} else {
-		mem_cgroup_put(s->memcg_params.memcg);
-		WRITE_ONCE(s->memcg_params.memcg, NULL);
-		percpu_ref_exit(&s->memcg_params.refcnt);
-	}
-}
-
-static void free_memcg_params(struct rcu_head *rcu)
-{
-	struct memcg_cache_array *old;
-
-	old = container_of(rcu, struct memcg_cache_array, rcu);
-	kvfree(old);
-}
-
-static int update_memcg_params(struct kmem_cache *s, int new_array_size)
-{
-	struct memcg_cache_array *old, *new;
-
-	new = kvzalloc(sizeof(struct memcg_cache_array) +
-		       new_array_size * sizeof(void *), GFP_KERNEL);
-	if (!new)
-		return -ENOMEM;
-
-	old = rcu_dereference_protected(s->memcg_params.memcg_caches,
-					lockdep_is_held(&slab_mutex));
-	if (old)
-		memcpy(new->entries, old->entries,
-		       memcg_nr_cache_ids * sizeof(void *));
-
-	rcu_assign_pointer(s->memcg_params.memcg_caches, new);
-	if (old)
-		call_rcu(&old->rcu, free_memcg_params);
-	return 0;
-}
-
-int memcg_update_all_caches(int num_memcgs)
-{
-	struct kmem_cache *s;
-	int ret = 0;
-
-	mutex_lock(&slab_mutex);
-	list_for_each_entry(s, &slab_root_caches, root_caches_node) {
-		ret = update_memcg_params(s, num_memcgs);
-		/*
-		 * Instead of freeing the memory, we'll just leave the caches
-		 * up to this point in an updated state.
-		 */
-		if (ret)
-			break;
-	}
-	mutex_unlock(&slab_mutex);
-	return ret;
+	else
+		slab_init_memcg_params(s);
 }
 
-void memcg_link_cache(struct kmem_cache *s, struct mem_cgroup *memcg)
+void memcg_link_cache(struct kmem_cache *s)
 {
-	if (is_root_cache(s)) {
+	if (is_root_cache(s))
 		list_add(&s->root_caches_node, &slab_root_caches);
-	} else {
-		css_get(&memcg->css);
-		s->memcg_params.memcg = memcg;
-		list_add(&s->memcg_params.children_node,
-			 &s->memcg_params.root_cache->memcg_params.children);
-		list_add(&s->memcg_params.kmem_caches_node,
-			 &s->memcg_params.memcg->kmem_caches);
-	}
 }
 
 static void memcg_unlink_cache(struct kmem_cache *s)
 {
-	if (is_root_cache(s)) {
+	if (is_root_cache(s))
 		list_del(&s->root_caches_node);
-	} else {
-		list_del(&s->memcg_params.children_node);
-		list_del(&s->memcg_params.kmem_caches_node);
-	}
 }
 #else
-static inline int init_memcg_params(struct kmem_cache *s,
-				    struct kmem_cache *root_cache)
-{
-	return 0;
-}
-
-static inline void destroy_memcg_params(struct kmem_cache *s)
+static inline void init_memcg_params(struct kmem_cache *s,
+				     struct kmem_cache *root_cache)
 {
 }
 
@@ -380,7 +275,7 @@ static struct kmem_cache *create_cache(const char *name,
 		unsigned int object_size, unsigned int align,
 		slab_flags_t flags, unsigned int useroffset,
 		unsigned int usersize, void (*ctor)(void *),
-		struct mem_cgroup *memcg, struct kmem_cache *root_cache)
+		struct kmem_cache *root_cache)
 {
 	struct kmem_cache *s;
 	int err;
@@ -400,24 +295,20 @@ static struct kmem_cache *create_cache(const char *name,
 	s->useroffset = useroffset;
 	s->usersize = usersize;
 
-	err = init_memcg_params(s, root_cache);
-	if (err)
-		goto out_free_cache;
-
+	init_memcg_params(s, root_cache);
 	err = __kmem_cache_create(s, flags);
 	if (err)
 		goto out_free_cache;
 
 	s->refcount = 1;
 	list_add(&s->list, &slab_caches);
-	memcg_link_cache(s, memcg);
+	memcg_link_cache(s);
 out:
 	if (err)
 		return ERR_PTR(err);
 	return s;
 
 out_free_cache:
-	destroy_memcg_params(s);
 	kmem_cache_free(kmem_cache, s);
 	goto out;
 }
@@ -504,7 +395,7 @@ kmem_cache_create_usercopy(const char *name,
 
 	s = create_cache(cache_name, size,
 			 calculate_alignment(flags, align, size),
-			 flags, useroffset, usersize, ctor, NULL, NULL);
+			 flags, useroffset, usersize, ctor, NULL);
 	if (IS_ERR(s)) {
 		err = PTR_ERR(s);
 		kfree_const(cache_name);
@@ -629,51 +520,27 @@ static int shutdown_cache(struct kmem_cache *s)
 
 #ifdef CONFIG_MEMCG_KMEM
 /*
- * memcg_create_kmem_cache - Create a cache for a memory cgroup.
- * @memcg: The memory cgroup the new cache is for.
+ * memcg_create_kmem_cache - Create a cache for non-root memory cgroups.
  * @root_cache: The parent of the new cache.
  *
  * This function attempts to create a kmem cache that will serve allocation
- * requests going from @memcg to @root_cache. The new cache inherits properties
- * from its parent.
+ * requests going all non-root memory cgroups to @root_cache. The new cache
+ * inherits properties from its parent.
  */
-void memcg_create_kmem_cache(struct mem_cgroup *memcg,
-			     struct kmem_cache *root_cache)
+void memcg_create_kmem_cache(struct kmem_cache *root_cache)
 {
-	static char memcg_name_buf[NAME_MAX + 1]; /* protected by slab_mutex */
-	struct cgroup_subsys_state *css = &memcg->css;
-	struct memcg_cache_array *arr;
 	struct kmem_cache *s = NULL;
 	char *cache_name;
-	int idx;
 
 	get_online_cpus();
 	get_online_mems();
 
 	mutex_lock(&slab_mutex);
 
-	/*
-	 * The memory cgroup could have been offlined while the cache
-	 * creation work was pending.
-	 */
-	if (memcg->kmem_state != KMEM_ONLINE)
+	if (root_cache->memcg_params.memcg_cache)
 		goto out_unlock;
 
-	idx = memcg_cache_id(memcg);
-	arr = rcu_dereference_protected(root_cache->memcg_params.memcg_caches,
-					lockdep_is_held(&slab_mutex));
-
-	/*
-	 * Since per-memcg caches are created asynchronously on first
-	 * allocation (see memcg_kmem_get_cache()), several threads can try to
-	 * create the same cache, but only one of them may succeed.
-	 */
-	if (arr->entries[idx])
-		goto out_unlock;
-
-	cgroup_name(css->cgroup, memcg_name_buf, sizeof(memcg_name_buf));
-	cache_name = kasprintf(GFP_KERNEL, "%s(%llu:%s)", root_cache->name,
-			       css->serial_nr, memcg_name_buf);
+	cache_name = kasprintf(GFP_KERNEL, "%s-memcg", root_cache->name);
 	if (!cache_name)
 		goto out_unlock;
 
@@ -681,7 +548,7 @@ void memcg_create_kmem_cache(struct mem_cgroup *memcg,
 			 root_cache->align,
 			 root_cache->flags & CACHE_CREATE_MASK,
 			 root_cache->useroffset, root_cache->usersize,
-			 root_cache->ctor, memcg, root_cache);
+			 root_cache->ctor, root_cache);
 	/*
 	 * If we could not create a memcg cache, do not complain, because
 	 * that's not critical at all as we can always proceed with the root
@@ -698,7 +565,7 @@ void memcg_create_kmem_cache(struct mem_cgroup *memcg,
 	 * initialized.
 	 */
 	smp_wmb();
-	arr->entries[idx] = s;
+	root_cache->memcg_params.memcg_cache = s;
 
 out_unlock:
 	mutex_unlock(&slab_mutex);
@@ -707,197 +574,18 @@ void memcg_create_kmem_cache(struct mem_cgroup *memcg,
 	put_online_cpus();
 }
 
-static void kmemcg_workfn(struct work_struct *work)
-{
-	struct kmem_cache *s = container_of(work, struct kmem_cache,
-					    memcg_params.work);
-
-	get_online_cpus();
-	get_online_mems();
-
-	mutex_lock(&slab_mutex);
-	s->memcg_params.work_fn(s);
-	mutex_unlock(&slab_mutex);
-
-	put_online_mems();
-	put_online_cpus();
-}
-
-static void kmemcg_rcufn(struct rcu_head *head)
-{
-	struct kmem_cache *s = container_of(head, struct kmem_cache,
-					    memcg_params.rcu_head);
-
-	/*
-	 * We need to grab blocking locks.  Bounce to ->work.  The
-	 * work item shares the space with the RCU head and can't be
-	 * initialized earlier.
-	 */
-	INIT_WORK(&s->memcg_params.work, kmemcg_workfn);
-	queue_work(memcg_kmem_cache_wq, &s->memcg_params.work);
-}
-
-static void kmemcg_cache_shutdown_fn(struct kmem_cache *s)
-{
-	WARN_ON(shutdown_cache(s));
-}
-
-static void kmemcg_cache_shutdown(struct percpu_ref *percpu_ref)
-{
-	struct kmem_cache *s = container_of(percpu_ref, struct kmem_cache,
-					    memcg_params.refcnt);
-	unsigned long flags;
-
-	spin_lock_irqsave(&memcg_kmem_wq_lock, flags);
-	if (s->memcg_params.root_cache->memcg_params.dying)
-		goto unlock;
-
-	s->memcg_params.work_fn = kmemcg_cache_shutdown_fn;
-	INIT_WORK(&s->memcg_params.work, kmemcg_workfn);
-	queue_work(memcg_kmem_cache_wq, &s->memcg_params.work);
-
-unlock:
-	spin_unlock_irqrestore(&memcg_kmem_wq_lock, flags);
-}
-
-static void kmemcg_cache_deactivate_after_rcu(struct kmem_cache *s)
-{
-	__kmemcg_cache_deactivate_after_rcu(s);
-	percpu_ref_kill(&s->memcg_params.refcnt);
-}
-
-static void kmemcg_cache_deactivate(struct kmem_cache *s)
-{
-	if (WARN_ON_ONCE(is_root_cache(s)))
-		return;
-
-	__kmemcg_cache_deactivate(s);
-	s->flags |= SLAB_DEACTIVATED;
-
-	/*
-	 * memcg_kmem_wq_lock is used to synchronize memcg_params.dying
-	 * flag and make sure that no new kmem_cache deactivation tasks
-	 * are queued (see flush_memcg_workqueue() ).
-	 */
-	spin_lock_irq(&memcg_kmem_wq_lock);
-	if (s->memcg_params.root_cache->memcg_params.dying)
-		goto unlock;
-
-	s->memcg_params.work_fn = kmemcg_cache_deactivate_after_rcu;
-	call_rcu(&s->memcg_params.rcu_head, kmemcg_rcufn);
-unlock:
-	spin_unlock_irq(&memcg_kmem_wq_lock);
-}
-
-void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg,
-				  struct mem_cgroup *parent)
-{
-	int idx;
-	struct memcg_cache_array *arr;
-	struct kmem_cache *s, *c;
-	unsigned int nr_reparented;
-
-	idx = memcg_cache_id(memcg);
-
-	get_online_cpus();
-	get_online_mems();
-
-	mutex_lock(&slab_mutex);
-	list_for_each_entry(s, &slab_root_caches, root_caches_node) {
-		arr = rcu_dereference_protected(s->memcg_params.memcg_caches,
-						lockdep_is_held(&slab_mutex));
-		c = arr->entries[idx];
-		if (!c)
-			continue;
-
-		kmemcg_cache_deactivate(c);
-		arr->entries[idx] = NULL;
-	}
-	nr_reparented = 0;
-	list_for_each_entry(s, &memcg->kmem_caches,
-			    memcg_params.kmem_caches_node) {
-		WRITE_ONCE(s->memcg_params.memcg, parent);
-		css_put(&memcg->css);
-		nr_reparented++;
-	}
-	if (nr_reparented) {
-		list_splice_init(&memcg->kmem_caches,
-				 &parent->kmem_caches);
-		css_get_many(&parent->css, nr_reparented);
-	}
-	mutex_unlock(&slab_mutex);
-
-	put_online_mems();
-	put_online_cpus();
-}
-
 static int shutdown_memcg_caches(struct kmem_cache *s)
 {
-	struct memcg_cache_array *arr;
-	struct kmem_cache *c, *c2;
-	LIST_HEAD(busy);
-	int i;
-
 	BUG_ON(!is_root_cache(s));
 
-	/*
-	 * First, shutdown active caches, i.e. caches that belong to online
-	 * memory cgroups.
-	 */
-	arr = rcu_dereference_protected(s->memcg_params.memcg_caches,
-					lockdep_is_held(&slab_mutex));
-	for_each_memcg_cache_index(i) {
-		c = arr->entries[i];
-		if (!c)
-			continue;
-		if (shutdown_cache(c))
-			/*
-			 * The cache still has objects. Move it to a temporary
-			 * list so as not to try to destroy it for a second
-			 * time while iterating over inactive caches below.
-			 */
-			list_move(&c->memcg_params.children_node, &busy);
-		else
-			/*
-			 * The cache is empty and will be destroyed soon. Clear
-			 * the pointer to it in the memcg_caches array so that
-			 * it will never be accessed even if the root cache
-			 * stays alive.
-			 */
-			arr->entries[i] = NULL;
-	}
-
-	/*
-	 * Second, shutdown all caches left from memory cgroups that are now
-	 * offline.
-	 */
-	list_for_each_entry_safe(c, c2, &s->memcg_params.children,
-				 memcg_params.children_node)
-		shutdown_cache(c);
-
-	list_splice(&busy, &s->memcg_params.children);
+	if (s->memcg_params.memcg_cache)
+		WARN_ON(shutdown_cache(s->memcg_params.memcg_cache));
 
-	/*
-	 * A cache being destroyed must be empty. In particular, this means
-	 * that all per memcg caches attached to it must be empty too.
-	 */
-	if (!list_empty(&s->memcg_params.children))
-		return -EBUSY;
 	return 0;
 }
 
 static void flush_memcg_workqueue(struct kmem_cache *s)
 {
-	spin_lock_irq(&memcg_kmem_wq_lock);
-	s->memcg_params.dying = true;
-	spin_unlock_irq(&memcg_kmem_wq_lock);
-
-	/*
-	 * SLAB and SLUB deactivate the kmem_caches through call_rcu. Make
-	 * sure all registered rcu callbacks have been invoked.
-	 */
-	rcu_barrier();
-
 	/*
 	 * SLAB and SLUB create memcg kmem_caches through workqueue and SLUB
 	 * deactivates the memcg kmem_caches through workqueue. Make sure all
@@ -905,18 +593,6 @@ static void flush_memcg_workqueue(struct kmem_cache *s)
 	 */
 	if (likely(memcg_kmem_cache_wq))
 		flush_workqueue(memcg_kmem_cache_wq);
-
-	/*
-	 * If we're racing with children kmem_cache deactivation, it might
-	 * take another rcu grace period to complete their destruction.
-	 * At this moment the corresponding percpu_ref_kill() call should be
-	 * done, but it might take another rcu grace period to complete
-	 * switching to the atomic mode.
-	 * Please, note that we check without grabbing the slab_mutex. It's safe
-	 * because at this moment the children list can't grow.
-	 */
-	if (!list_empty(&s->memcg_params.children))
-		rcu_barrier();
 }
 #else
 static inline int shutdown_memcg_caches(struct kmem_cache *s)
@@ -932,7 +608,6 @@ static inline void flush_memcg_workqueue(struct kmem_cache *s)
 void slab_kmem_cache_release(struct kmem_cache *s)
 {
 	__kmem_cache_release(s);
-	destroy_memcg_params(s);
 	kfree_const(s->name);
 	kmem_cache_free(kmem_cache, s);
 }
@@ -996,7 +671,7 @@ int kmem_cache_shrink(struct kmem_cache *cachep)
 EXPORT_SYMBOL(kmem_cache_shrink);
 
 /**
- * kmem_cache_shrink_all - shrink a cache and all memcg caches for root cache
+ * kmem_cache_shrink_all - shrink root and memcg caches
  * @s: The cache pointer
  */
 void kmem_cache_shrink_all(struct kmem_cache *s)
@@ -1013,21 +688,11 @@ void kmem_cache_shrink_all(struct kmem_cache *s)
 	kasan_cache_shrink(s);
 	__kmem_cache_shrink(s);
 
-	/*
-	 * We have to take the slab_mutex to protect from the memcg list
-	 * modification.
-	 */
-	mutex_lock(&slab_mutex);
-	for_each_memcg_cache(c, s) {
-		/*
-		 * Don't need to shrink deactivated memcg caches.
-		 */
-		if (s->flags & SLAB_DEACTIVATED)
-			continue;
+	c = memcg_cache(s);
+	if (c) {
 		kasan_cache_shrink(c);
 		__kmem_cache_shrink(c);
 	}
-	mutex_unlock(&slab_mutex);
 	put_online_mems();
 	put_online_cpus();
 }
@@ -1082,7 +747,7 @@ struct kmem_cache *__init create_kmalloc_cache(const char *name,
 
 	create_boot_cache(s, name, size, flags, useroffset, usersize);
 	list_add(&s->list, &slab_caches);
-	memcg_link_cache(s, NULL);
+	memcg_link_cache(s);
 	s->refcount = 1;
 	return s;
 }
@@ -1445,7 +1110,8 @@ memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info)
 	if (!is_root_cache(s))
 		return;
 
-	for_each_memcg_cache(c, s) {
+	c = memcg_cache(s);
+	if (c) {
 		memset(&sinfo, 0, sizeof(sinfo));
 		get_slabinfo(c, &sinfo);
 
@@ -1576,7 +1242,7 @@ module_init(slab_proc_init);
 
 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_MEMCG_KMEM)
 /*
- * Display information about kmem caches that have child memcg caches.
+ * Display information about kmem caches that have memcg cache.
  */
 static int memcg_slabinfo_show(struct seq_file *m, void *unused)
 {
@@ -1588,9 +1254,9 @@ static int memcg_slabinfo_show(struct seq_file *m, void *unused)
 	seq_puts(m, " <active_slabs> <num_slabs>\n");
 	list_for_each_entry(s, &slab_root_caches, root_caches_node) {
 		/*
-		 * Skip kmem caches that don't have any memcg children.
+		 * Skip kmem caches that don't have the memcg cache.
 		 */
-		if (list_empty(&s->memcg_params.children))
+		if (!s->memcg_params.memcg_cache)
 			continue;
 
 		memset(&sinfo, 0, sizeof(sinfo));
@@ -1599,23 +1265,13 @@ static int memcg_slabinfo_show(struct seq_file *m, void *unused)
 			   cache_name(s), sinfo.active_objs, sinfo.num_objs,
 			   sinfo.active_slabs, sinfo.num_slabs);
 
-		for_each_memcg_cache(c, s) {
-			struct cgroup_subsys_state *css;
-			char *status = "";
-
-			css = &c->memcg_params.memcg->css;
-			if (!(css->flags & CSS_ONLINE))
-				status = ":dead";
-			else if (c->flags & SLAB_DEACTIVATED)
-				status = ":deact";
-
-			memset(&sinfo, 0, sizeof(sinfo));
-			get_slabinfo(c, &sinfo);
-			seq_printf(m, "%-17s %4d%-6s %6lu %6lu %6lu %6lu\n",
-				   cache_name(c), css->id, status,
-				   sinfo.active_objs, sinfo.num_objs,
-				   sinfo.active_slabs, sinfo.num_slabs);
-		}
+		c = s->memcg_params.memcg_cache;
+		memset(&sinfo, 0, sizeof(sinfo));
+		get_slabinfo(c, &sinfo);
+		seq_printf(m, "%-17s %4d %6lu %6lu %6lu %6lu\n",
+			   cache_name(c), root_mem_cgroup->css.id,
+			   sinfo.active_objs, sinfo.num_objs,
+			   sinfo.active_slabs, sinfo.num_slabs);
 	}
 	mutex_unlock(&slab_mutex);
 	return 0;
diff --git a/mm/slub.c b/mm/slub.c
index 25810980a26c..91a1dce932e9 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4208,36 +4208,6 @@ int __kmem_cache_shrink(struct kmem_cache *s)
 	return ret;
 }
 
-#ifdef CONFIG_MEMCG
-void __kmemcg_cache_deactivate_after_rcu(struct kmem_cache *s)
-{
-	/*
-	 * Called with all the locks held after a sched RCU grace period.
-	 * Even if @s becomes empty after shrinking, we can't know that @s
-	 * doesn't have allocations already in-flight and thus can't
-	 * destroy @s until the associated memcg is released.
-	 *
-	 * However, let's remove the sysfs files for empty caches here.
-	 * Each cache has a lot of interface files which aren't
-	 * particularly useful for empty draining caches; otherwise, we can
-	 * easily end up with millions of unnecessary sysfs files on
-	 * systems which have a lot of memory and transient cgroups.
-	 */
-	if (!__kmem_cache_shrink(s))
-		sysfs_slab_remove(s);
-}
-
-void __kmemcg_cache_deactivate(struct kmem_cache *s)
-{
-	/*
-	 * Disable empty slabs caching. Used to avoid pinning offline
-	 * memory cgroups by kmem pages that can be freed.
-	 */
-	slub_set_cpu_partial(s, 0);
-	s->min_partial = 0;
-}
-#endif	/* CONFIG_MEMCG */
-
 static int slab_mem_going_offline_callback(void *arg)
 {
 	struct kmem_cache *s;
@@ -4394,7 +4364,7 @@ static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
 	}
 	slab_init_memcg_params(s);
 	list_add(&s->list, &slab_caches);
-	memcg_link_cache(s, NULL);
+	memcg_link_cache(s);
 	return s;
 }
 
@@ -4462,7 +4432,8 @@ __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
 		s->object_size = max(s->object_size, size);
 		s->inuse = max(s->inuse, ALIGN(size, sizeof(void *)));
 
-		for_each_memcg_cache(c, s) {
+		c = memcg_cache(s);
+		if (c) {
 			c->object_size = s->object_size;
 			c->inuse = max(c->inuse, ALIGN(size, sizeof(void *)));
 		}
@@ -5595,7 +5566,8 @@ static ssize_t slab_attr_store(struct kobject *kobj,
 		 * directly either failed or succeeded, in which case we loop
 		 * through the descendants with best-effort propagation.
 		 */
-		for_each_memcg_cache(c, s)
+		c = memcg_cache(s);
+		if (c)
 			attribute->store(c, buf, len);
 		mutex_unlock(&slab_mutex);
 	}
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 13/19] mm: memcg/slab: simplify memcg cache creation
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
                   ` (11 preceding siblings ...)
  2020-06-23  1:58 ` [PATCH v7 12/19] mm: memcg/slab: use a single set of kmem_caches for all accounted allocations Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 14/19] mm: memcg/slab: remove memcg_kmem_get_cache() Roman Gushchin
                   ` (6 subsequent siblings)
  19 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

Because the number of non-root kmem_caches doesn't depend on the number of
memory cgroups anymore and is generally not very big, there is no more
need for a dedicated workqueue.

Also, as there is no more need to pass any arguments to the
memcg_create_kmem_cache() except the root kmem_cache, it's possible to
just embed the work structure into the kmem_cache and avoid the dynamic
allocation of the work structure.

This will also simplify the synchronization: for each root kmem_cache
there is only one work.  So there will be no more concurrent attempts to
create a non-root kmem_cache for a root kmem_cache: the second and all
following attempts to queue the work will fail.

On the kmem_cache destruction path there is no more need to call the
expensive flush_workqueue() and wait for all pending works to be finished.
Instead, cancel_work_sync() can be used to cancel/wait for only one work.

Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 include/linux/memcontrol.h |  1 -
 mm/memcontrol.c            | 48 +-------------------------------------
 mm/slab.h                  |  2 ++
 mm/slab_common.c           | 22 +++++++++--------
 4 files changed, 15 insertions(+), 58 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 11fd18b3d6c6..2ac84dcfc9e5 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1418,7 +1418,6 @@ int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size);
 void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size);
 
 extern struct static_key_false memcg_kmem_enabled_key;
-extern struct workqueue_struct *memcg_kmem_cache_wq;
 
 extern int memcg_nr_cache_ids;
 void memcg_get_cache_ids(void);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 417070fb0fd0..d23c2bdeea66 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -399,8 +399,6 @@ void memcg_put_cache_ids(void)
  */
 DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key);
 EXPORT_SYMBOL(memcg_kmem_enabled_key);
-
-struct workqueue_struct *memcg_kmem_cache_wq;
 #endif
 
 static int memcg_shrinker_map_size;
@@ -2902,39 +2900,6 @@ static void memcg_free_cache_id(int id)
 	ida_simple_remove(&memcg_cache_ida, id);
 }
 
-struct memcg_kmem_cache_create_work {
-	struct kmem_cache *cachep;
-	struct work_struct work;
-};
-
-static void memcg_kmem_cache_create_func(struct work_struct *w)
-{
-	struct memcg_kmem_cache_create_work *cw =
-		container_of(w, struct memcg_kmem_cache_create_work, work);
-	struct kmem_cache *cachep = cw->cachep;
-
-	memcg_create_kmem_cache(cachep);
-
-	kfree(cw);
-}
-
-/*
- * Enqueue the creation of a per-memcg kmem_cache.
- */
-static void memcg_schedule_kmem_cache_create(struct kmem_cache *cachep)
-{
-	struct memcg_kmem_cache_create_work *cw;
-
-	cw = kmalloc(sizeof(*cw), GFP_NOWAIT | __GFP_NOWARN);
-	if (!cw)
-		return;
-
-	cw->cachep = cachep;
-	INIT_WORK(&cw->work, memcg_kmem_cache_create_func);
-
-	queue_work(memcg_kmem_cache_wq, &cw->work);
-}
-
 /**
  * memcg_kmem_get_cache: select memcg or root cache for allocation
  * @cachep: the original global kmem cache
@@ -2951,7 +2916,7 @@ struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep)
 
 	memcg_cachep = READ_ONCE(cachep->memcg_params.memcg_cache);
 	if (unlikely(!memcg_cachep)) {
-		memcg_schedule_kmem_cache_create(cachep);
+		queue_work(system_wq, &cachep->memcg_params.work);
 		return cachep;
 	}
 
@@ -7026,17 +6991,6 @@ static int __init mem_cgroup_init(void)
 {
 	int cpu, node;
 
-#ifdef CONFIG_MEMCG_KMEM
-	/*
-	 * Kmem cache creation is mostly done with the slab_mutex held,
-	 * so use a workqueue with limited concurrency to avoid stalling
-	 * all worker threads in case lots of cgroups are created and
-	 * destroyed simultaneously.
-	 */
-	memcg_kmem_cache_wq = alloc_workqueue("memcg_kmem_cache", 0, 1);
-	BUG_ON(!memcg_kmem_cache_wq);
-#endif
-
 	cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD, "mm/memctrl:dead", NULL,
 				  memcg_hotplug_cpu_dead);
 
diff --git a/mm/slab.h b/mm/slab.h
index 673448e5cfb3..66482f8467e7 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -45,12 +45,14 @@ struct kmem_cache {
  * @memcg_cache: pointer to memcg kmem cache, used by all non-root memory
  *		cgroups.
  * @root_caches_node: list node for slab_root_caches list.
+ * @work: work struct used to create the non-root cache.
  */
 struct memcg_cache_params {
 	struct kmem_cache *root_cache;
 
 	struct kmem_cache *memcg_cache;
 	struct list_head __root_caches_node;
+	struct work_struct work;
 };
 #endif /* CONFIG_SLOB */
 
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 90c25c8db1a5..fe4f5be0e51f 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -132,10 +132,18 @@ int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr,
 
 LIST_HEAD(slab_root_caches);
 
+static void memcg_kmem_cache_create_func(struct work_struct *work)
+{
+	struct kmem_cache *cachep = container_of(work, struct kmem_cache,
+						 memcg_params.work);
+	memcg_create_kmem_cache(cachep);
+}
+
 void slab_init_memcg_params(struct kmem_cache *s)
 {
 	s->memcg_params.root_cache = NULL;
 	s->memcg_params.memcg_cache = NULL;
+	INIT_WORK(&s->memcg_params.work, memcg_kmem_cache_create_func);
 }
 
 static void init_memcg_params(struct kmem_cache *s,
@@ -584,15 +592,9 @@ static int shutdown_memcg_caches(struct kmem_cache *s)
 	return 0;
 }
 
-static void flush_memcg_workqueue(struct kmem_cache *s)
+static void cancel_memcg_cache_creation(struct kmem_cache *s)
 {
-	/*
-	 * SLAB and SLUB create memcg kmem_caches through workqueue and SLUB
-	 * deactivates the memcg kmem_caches through workqueue. Make sure all
-	 * previous workitems on workqueue are processed.
-	 */
-	if (likely(memcg_kmem_cache_wq))
-		flush_workqueue(memcg_kmem_cache_wq);
+	cancel_work_sync(&s->memcg_params.work);
 }
 #else
 static inline int shutdown_memcg_caches(struct kmem_cache *s)
@@ -600,7 +602,7 @@ static inline int shutdown_memcg_caches(struct kmem_cache *s)
 	return 0;
 }
 
-static inline void flush_memcg_workqueue(struct kmem_cache *s)
+static inline void cancel_memcg_cache_creation(struct kmem_cache *s)
 {
 }
 #endif /* CONFIG_MEMCG_KMEM */
@@ -619,7 +621,7 @@ void kmem_cache_destroy(struct kmem_cache *s)
 	if (unlikely(!s))
 		return;
 
-	flush_memcg_workqueue(s);
+	cancel_memcg_cache_creation(s);
 
 	get_online_cpus();
 	get_online_mems();
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 14/19] mm: memcg/slab: remove memcg_kmem_get_cache()
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
                   ` (12 preceding siblings ...)
  2020-06-23  1:58 ` [PATCH v7 13/19] mm: memcg/slab: simplify memcg cache creation Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 15/19] mm: memcg/slab: deprecate slab_root_caches Roman Gushchin
                   ` (5 subsequent siblings)
  19 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

The memcg_kmem_get_cache() function became really trivial, so let's just
inline it into the single call point: memcg_slab_pre_alloc_hook().

It will make the code less bulky and can also help the compiler to
generate a better code.

Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 include/linux/memcontrol.h |  2 --
 mm/memcontrol.c            | 25 +------------------------
 mm/slab.h                  | 11 +++++++++--
 mm/slab_common.c           |  2 +-
 4 files changed, 11 insertions(+), 29 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 2ac84dcfc9e5..5a8b62d075e6 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1403,8 +1403,6 @@ static inline void memcg_set_shrinker_bit(struct mem_cgroup *memcg,
 }
 #endif
 
-struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep);
-
 #ifdef CONFIG_MEMCG_KMEM
 int __memcg_kmem_charge(struct mem_cgroup *memcg, gfp_t gfp,
 			unsigned int nr_pages);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d23c2bdeea66..c910fe326ca6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -393,7 +393,7 @@ void memcg_put_cache_ids(void)
 
 /*
  * A lot of the calls to the cache allocation functions are expected to be
- * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
+ * inlined by the compiler. Since the calls to memcg_slab_pre_alloc_hook() are
  * conditional to this static branch, we'll have to allow modules that does
  * kmem_cache_alloc and the such to see this symbol as well
  */
@@ -2900,29 +2900,6 @@ static void memcg_free_cache_id(int id)
 	ida_simple_remove(&memcg_cache_ida, id);
 }
 
-/**
- * memcg_kmem_get_cache: select memcg or root cache for allocation
- * @cachep: the original global kmem cache
- *
- * Return the kmem_cache we're supposed to use for a slab allocation.
- *
- * If the cache does not exist yet, if we are the first user of it, we
- * create it asynchronously in a workqueue and let the current allocation
- * go through with the original cache.
- */
-struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep)
-{
-	struct kmem_cache *memcg_cachep;
-
-	memcg_cachep = READ_ONCE(cachep->memcg_params.memcg_cache);
-	if (unlikely(!memcg_cachep)) {
-		queue_work(system_wq, &cachep->memcg_params.work);
-		return cachep;
-	}
-
-	return memcg_cachep;
-}
-
 /**
  * __memcg_kmem_charge: charge a number of kernel pages to a memcg
  * @memcg: memory cgroup to charge
diff --git a/mm/slab.h b/mm/slab.h
index 66482f8467e7..d47430e97ff1 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -364,9 +364,16 @@ static inline struct kmem_cache *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
 	if (memcg_kmem_bypass())
 		return s;
 
-	cachep = memcg_kmem_get_cache(s);
-	if (is_root_cache(cachep))
+	cachep = READ_ONCE(s->memcg_params.memcg_cache);
+	if (unlikely(!cachep)) {
+		/*
+		 * If memcg cache does not exist yet, we schedule it's
+		 * asynchronous creation and let the current allocation
+		 * go through with the root cache.
+		 */
+		queue_work(system_wq, &s->memcg_params.work);
 		return s;
+	}
 
 	objcg = get_obj_cgroup_from_current();
 	if (!objcg)
diff --git a/mm/slab_common.c b/mm/slab_common.c
index fe4f5be0e51f..e0a2a904fdd9 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -568,7 +568,7 @@ void memcg_create_kmem_cache(struct kmem_cache *root_cache)
 	}
 
 	/*
-	 * Since readers won't lock (see memcg_kmem_get_cache()), we need a
+	 * Since readers won't lock (see memcg_slab_pre_alloc_hook()), we need a
 	 * barrier here to ensure nobody will see the kmem_cache partially
 	 * initialized.
 	 */
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 15/19] mm: memcg/slab: deprecate slab_root_caches
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
                   ` (13 preceding siblings ...)
  2020-06-23  1:58 ` [PATCH v7 14/19] mm: memcg/slab: remove memcg_kmem_get_cache() Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 16/19] mm: memcg/slab: remove redundant check in memcg_accumulate_slabinfo() Roman Gushchin
                   ` (4 subsequent siblings)
  19 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

Currently there are two lists of kmem_caches:
1) slab_caches, which contains all kmem_caches,
2) slab_root_caches, which contains only root kmem_caches.

And there is some preprocessor magic to have a single list if
CONFIG_MEMCG_KMEM isn't enabled.

It was required earlier because the number of non-root kmem_caches was
proportional to the number of memory cgroups and could reach really big
values.  Now, when it cannot exceed the number of root kmem_caches, there
is really no reason to maintain two lists.

We never iterate over the slab_root_caches list on any hot paths, so it's
perfectly fine to iterate over slab_caches and filter out non-root
kmem_caches.

It allows to remove a lot of config-dependent code and two pointers from
the kmem_cache structure.

Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 mm/slab.c        |  1 -
 mm/slab.h        | 17 -----------------
 mm/slab_common.c | 37 ++++++++-----------------------------
 mm/slub.c        |  1 -
 4 files changed, 8 insertions(+), 48 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index 84e218fd0bcf..23f0376f66ba 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1239,7 +1239,6 @@ void __init kmem_cache_init(void)
 				  nr_node_ids * sizeof(struct kmem_cache_node *),
 				  SLAB_HWCACHE_ALIGN, 0, 0);
 	list_add(&kmem_cache->list, &slab_caches);
-	memcg_link_cache(kmem_cache);
 	slab_state = PARTIAL;
 
 	/*
diff --git a/mm/slab.h b/mm/slab.h
index d47430e97ff1..46ac1de9a0b7 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -44,14 +44,12 @@ struct kmem_cache {
  *
  * @memcg_cache: pointer to memcg kmem cache, used by all non-root memory
  *		cgroups.
- * @root_caches_node: list node for slab_root_caches list.
  * @work: work struct used to create the non-root cache.
  */
 struct memcg_cache_params {
 	struct kmem_cache *root_cache;
 
 	struct kmem_cache *memcg_cache;
-	struct list_head __root_caches_node;
 	struct work_struct work;
 };
 #endif /* CONFIG_SLOB */
@@ -264,11 +262,6 @@ static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t fla
 }
 
 #ifdef CONFIG_MEMCG_KMEM
-
-/* List of all root caches. */
-extern struct list_head		slab_root_caches;
-#define root_caches_node	memcg_params.__root_caches_node
-
 static inline bool is_root_cache(struct kmem_cache *s)
 {
 	return !s->memcg_params.root_cache;
@@ -446,14 +439,8 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page,
 }
 
 extern void slab_init_memcg_params(struct kmem_cache *);
-extern void memcg_link_cache(struct kmem_cache *s);
 
 #else /* CONFIG_MEMCG_KMEM */
-
-/* If !memcg, all caches are root. */
-#define slab_root_caches	slab_caches
-#define root_caches_node	list
-
 static inline bool is_root_cache(struct kmem_cache *s)
 {
 	return true;
@@ -522,10 +509,6 @@ static inline void slab_init_memcg_params(struct kmem_cache *s)
 {
 }
 
-static inline void memcg_link_cache(struct kmem_cache *s)
-{
-}
-
 #endif /* CONFIG_MEMCG_KMEM */
 
 static inline struct kmem_cache *virt_to_cache(const void *obj)
diff --git a/mm/slab_common.c b/mm/slab_common.c
index e0a2a904fdd9..0618d3595c08 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -129,9 +129,6 @@ int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr,
 }
 
 #ifdef CONFIG_MEMCG_KMEM
-
-LIST_HEAD(slab_root_caches);
-
 static void memcg_kmem_cache_create_func(struct work_struct *work)
 {
 	struct kmem_cache *cachep = container_of(work, struct kmem_cache,
@@ -154,27 +151,11 @@ static void init_memcg_params(struct kmem_cache *s,
 	else
 		slab_init_memcg_params(s);
 }
-
-void memcg_link_cache(struct kmem_cache *s)
-{
-	if (is_root_cache(s))
-		list_add(&s->root_caches_node, &slab_root_caches);
-}
-
-static void memcg_unlink_cache(struct kmem_cache *s)
-{
-	if (is_root_cache(s))
-		list_del(&s->root_caches_node);
-}
 #else
 static inline void init_memcg_params(struct kmem_cache *s,
 				     struct kmem_cache *root_cache)
 {
 }
-
-static inline void memcg_unlink_cache(struct kmem_cache *s)
-{
-}
 #endif /* CONFIG_MEMCG_KMEM */
 
 /*
@@ -251,7 +232,7 @@ struct kmem_cache *find_mergeable(unsigned int size, unsigned int align,
 	if (flags & SLAB_NEVER_MERGE)
 		return NULL;
 
-	list_for_each_entry_reverse(s, &slab_root_caches, root_caches_node) {
+	list_for_each_entry_reverse(s, &slab_caches, list) {
 		if (slab_unmergeable(s))
 			continue;
 
@@ -310,7 +291,6 @@ static struct kmem_cache *create_cache(const char *name,
 
 	s->refcount = 1;
 	list_add(&s->list, &slab_caches);
-	memcg_link_cache(s);
 out:
 	if (err)
 		return ERR_PTR(err);
@@ -505,7 +485,6 @@ static int shutdown_cache(struct kmem_cache *s)
 	if (__kmem_cache_shutdown(s) != 0)
 		return -EBUSY;
 
-	memcg_unlink_cache(s);
 	list_del(&s->list);
 
 	if (s->flags & SLAB_TYPESAFE_BY_RCU) {
@@ -749,7 +728,6 @@ struct kmem_cache *__init create_kmalloc_cache(const char *name,
 
 	create_boot_cache(s, name, size, flags, useroffset, usersize);
 	list_add(&s->list, &slab_caches);
-	memcg_link_cache(s);
 	s->refcount = 1;
 	return s;
 }
@@ -1090,12 +1068,12 @@ static void print_slabinfo_header(struct seq_file *m)
 void *slab_start(struct seq_file *m, loff_t *pos)
 {
 	mutex_lock(&slab_mutex);
-	return seq_list_start(&slab_root_caches, *pos);
+	return seq_list_start(&slab_caches, *pos);
 }
 
 void *slab_next(struct seq_file *m, void *p, loff_t *pos)
 {
-	return seq_list_next(p, &slab_root_caches, pos);
+	return seq_list_next(p, &slab_caches, pos);
 }
 
 void slab_stop(struct seq_file *m, void *p)
@@ -1148,11 +1126,12 @@ static void cache_show(struct kmem_cache *s, struct seq_file *m)
 
 static int slab_show(struct seq_file *m, void *p)
 {
-	struct kmem_cache *s = list_entry(p, struct kmem_cache, root_caches_node);
+	struct kmem_cache *s = list_entry(p, struct kmem_cache, list);
 
-	if (p == slab_root_caches.next)
+	if (p == slab_caches.next)
 		print_slabinfo_header(m);
-	cache_show(s, m);
+	if (is_root_cache(s))
+		cache_show(s, m);
 	return 0;
 }
 
@@ -1254,7 +1233,7 @@ static int memcg_slabinfo_show(struct seq_file *m, void *unused)
 	mutex_lock(&slab_mutex);
 	seq_puts(m, "# <name> <css_id[:dead|deact]> <active_objs> <num_objs>");
 	seq_puts(m, " <active_slabs> <num_slabs>\n");
-	list_for_each_entry(s, &slab_root_caches, root_caches_node) {
+	list_for_each_entry(s, &slab_caches, list) {
 		/*
 		 * Skip kmem caches that don't have the memcg cache.
 		 */
diff --git a/mm/slub.c b/mm/slub.c
index 91a1dce932e9..7a5d6861b088 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4364,7 +4364,6 @@ static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
 	}
 	slab_init_memcg_params(s);
 	list_add(&s->list, &slab_caches);
-	memcg_link_cache(s);
 	return s;
 }
 
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 16/19] mm: memcg/slab: remove redundant check in memcg_accumulate_slabinfo()
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
                   ` (14 preceding siblings ...)
  2020-06-23  1:58 ` [PATCH v7 15/19] mm: memcg/slab: deprecate slab_root_caches Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 17/19] mm: memcg/slab: use a single set of kmem_caches for all allocations Roman Gushchin
                   ` (3 subsequent siblings)
  19 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

memcg_accumulate_slabinfo() is never called with a non-root kmem_cache as
a first argument, so the is_root_cache(s) check is redundant and can be
removed without any functional change.

Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 mm/slab_common.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 0618d3595c08..e546778030a2 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1087,9 +1087,6 @@ memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info)
 	struct kmem_cache *c;
 	struct slabinfo sinfo;
 
-	if (!is_root_cache(s))
-		return;
-
 	c = memcg_cache(s);
 	if (c) {
 		memset(&sinfo, 0, sizeof(sinfo));
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 17/19] mm: memcg/slab: use a single set of kmem_caches for all allocations
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
                   ` (15 preceding siblings ...)
  2020-06-23  1:58 ` [PATCH v7 16/19] mm: memcg/slab: remove redundant check in memcg_accumulate_slabinfo() Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  5:25   ` Shakeel Butt
  2020-06-23  1:58 ` [PATCH v7 18/19] kselftests: cgroup: add kernel memory accounting tests Roman Gushchin
                   ` (2 subsequent siblings)
  19 siblings, 1 reply; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

Instead of having two sets of kmem_caches: one for system-wide and
non-accounted allocations and the second one shared by all accounted
allocations, we can use just one.

The idea is simple: space for obj_cgroup metadata can be allocated on
demand and filled only for accounted allocations.

It allows to remove a bunch of code which is required to handle kmem_cache
clones for accounted allocations.  There is no more need to create them,
accumulate statistics, propagate attributes, etc.  It's a quite
significant simplification.

Also, because the total number of slab_caches is reduced almost twice (not
all kmem_caches have a memcg clone), some additional memory savings are
expected.  On my devvm it additionally saves about 3.5% of slab memory.

Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
---
 include/linux/slab.h     |   2 -
 include/linux/slab_def.h |   3 -
 include/linux/slub_def.h |  10 --
 mm/memcontrol.c          |   5 +-
 mm/slab.c                |  41 +------
 mm/slab.h                | 185 ++++++++-----------------------
 mm/slab_common.c         | 230 +--------------------------------------
 mm/slub.c                | 163 +--------------------------
 8 files changed, 62 insertions(+), 577 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 8b1f91e320f9..24df2393ec03 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -155,8 +155,6 @@ struct kmem_cache *kmem_cache_create_usercopy(const char *name,
 void kmem_cache_destroy(struct kmem_cache *);
 int kmem_cache_shrink(struct kmem_cache *);
 
-void memcg_create_kmem_cache(struct kmem_cache *cachep);
-
 /*
  * Please use this macro to create slab caches. Simply specify the
  * name of the structure and maybe some flags that are listed above.
diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index ccda7b9669a5..9eb430c163c2 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -72,9 +72,6 @@ struct kmem_cache {
 	int obj_offset;
 #endif /* CONFIG_DEBUG_SLAB */
 
-#ifdef CONFIG_MEMCG
-	struct memcg_cache_params memcg_params;
-#endif
 #ifdef CONFIG_KASAN
 	struct kasan_cache kasan_info;
 #endif
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index f87302dcfe8c..1be0ed5befa1 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -108,17 +108,7 @@ struct kmem_cache {
 	struct list_head list;	/* List of slab caches */
 #ifdef CONFIG_SYSFS
 	struct kobject kobj;	/* For sysfs */
-	struct work_struct kobj_remove_work;
 #endif
-#ifdef CONFIG_MEMCG
-	struct memcg_cache_params memcg_params;
-	/* For propagation, maximum size of a stored attr */
-	unsigned int max_attr_size;
-#ifdef CONFIG_SYSFS
-	struct kset *memcg_kset;
-#endif
-#endif
-
 #ifdef CONFIG_SLAB_FREELIST_HARDENED
 	unsigned long random;
 #endif
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c910fe326ca6..1b858cd18b52 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2826,7 +2826,10 @@ struct mem_cgroup *mem_cgroup_from_obj(void *p)
 
 		off = obj_to_index(page->slab_cache, page, p);
 		objcg = page_obj_cgroups(page)[off];
-		return obj_cgroup_memcg(objcg);
+		if (objcg)
+			return obj_cgroup_memcg(objcg);
+
+		return NULL;
 	}
 
 	/* All other pages use page->mem_cgroup */
diff --git a/mm/slab.c b/mm/slab.c
index 23f0376f66ba..ebac5e400ad0 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1369,11 +1369,7 @@ static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
 		return NULL;
 	}
 
-	if (charge_slab_page(page, flags, cachep->gfporder, cachep)) {
-		__free_pages(page, cachep->gfporder);
-		return NULL;
-	}
-
+	charge_slab_page(page, flags, cachep->gfporder, cachep);
 	__SetPageSlab(page);
 	/* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
 	if (sk_memalloc_socks() && page_is_pfmemalloc(page))
@@ -3792,8 +3788,8 @@ static int setup_kmem_cache_nodes(struct kmem_cache *cachep, gfp_t gfp)
 }
 
 /* Always called with the slab_mutex held */
-static int __do_tune_cpucache(struct kmem_cache *cachep, int limit,
-				int batchcount, int shared, gfp_t gfp)
+static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
+			    int batchcount, int shared, gfp_t gfp)
 {
 	struct array_cache __percpu *cpu_cache, *prev;
 	int cpu;
@@ -3838,30 +3834,6 @@ static int __do_tune_cpucache(struct kmem_cache *cachep, int limit,
 	return setup_kmem_cache_nodes(cachep, gfp);
 }
 
-static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
-				int batchcount, int shared, gfp_t gfp)
-{
-	int ret;
-	struct kmem_cache *c;
-
-	ret = __do_tune_cpucache(cachep, limit, batchcount, shared, gfp);
-
-	if (slab_state < FULL)
-		return ret;
-
-	if ((ret < 0) || !is_root_cache(cachep))
-		return ret;
-
-	lockdep_assert_held(&slab_mutex);
-	c = memcg_cache(cachep);
-	if (c) {
-		/* return value determined by the root cache only */
-		__do_tune_cpucache(c, limit, batchcount, shared, gfp);
-	}
-
-	return ret;
-}
-
 /* Called with slab_mutex held always */
 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp)
 {
@@ -3874,13 +3846,6 @@ static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp)
 	if (err)
 		goto end;
 
-	if (!is_root_cache(cachep)) {
-		struct kmem_cache *root = memcg_root_cache(cachep);
-		limit = root->limit;
-		shared = root->shared;
-		batchcount = root->batchcount;
-	}
-
 	if (limit && shared && batchcount)
 		goto skip_setup;
 	/*
diff --git a/mm/slab.h b/mm/slab.h
index 46ac1de9a0b7..893d39739ed6 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -30,28 +30,6 @@ struct kmem_cache {
 	struct list_head list;	/* List of all slab caches on the system */
 };
 
-#else /* !CONFIG_SLOB */
-
-/*
- * This is the main placeholder for memcg-related information in kmem caches.
- * Both the root cache and the child cache will have it. Some fields are used
- * in both cases, other are specific to root caches.
- *
- * @root_cache:	Common to root and child caches.  NULL for root, pointer to
- *		the root cache for children.
- *
- * The following fields are specific to root caches.
- *
- * @memcg_cache: pointer to memcg kmem cache, used by all non-root memory
- *		cgroups.
- * @work: work struct used to create the non-root cache.
- */
-struct memcg_cache_params {
-	struct kmem_cache *root_cache;
-
-	struct kmem_cache *memcg_cache;
-	struct work_struct work;
-};
 #endif /* CONFIG_SLOB */
 
 #ifdef CONFIG_SLAB
@@ -195,7 +173,6 @@ int __kmem_cache_shutdown(struct kmem_cache *);
 void __kmem_cache_release(struct kmem_cache *);
 int __kmem_cache_shrink(struct kmem_cache *);
 void slab_kmem_cache_release(struct kmem_cache *);
-void kmem_cache_shrink_all(struct kmem_cache *s);
 
 struct seq_file;
 struct file;
@@ -262,43 +239,6 @@ static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t fla
 }
 
 #ifdef CONFIG_MEMCG_KMEM
-static inline bool is_root_cache(struct kmem_cache *s)
-{
-	return !s->memcg_params.root_cache;
-}
-
-static inline bool slab_equal_or_root(struct kmem_cache *s,
-				      struct kmem_cache *p)
-{
-	return p == s || p == s->memcg_params.root_cache;
-}
-
-/*
- * We use suffixes to the name in memcg because we can't have caches
- * created in the system with the same name. But when we print them
- * locally, better refer to them with the base name
- */
-static inline const char *cache_name(struct kmem_cache *s)
-{
-	if (!is_root_cache(s))
-		s = s->memcg_params.root_cache;
-	return s->name;
-}
-
-static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
-{
-	if (is_root_cache(s))
-		return s;
-	return s->memcg_params.root_cache;
-}
-
-static inline struct kmem_cache *memcg_cache(struct kmem_cache *s)
-{
-	if (is_root_cache(s))
-		return s->memcg_params.memcg_cache;
-	return NULL;
-}
-
 static inline struct obj_cgroup **page_obj_cgroups(struct page *page)
 {
 	/*
@@ -327,8 +267,12 @@ static inline int memcg_alloc_page_obj_cgroups(struct page *page,
 	if (!vec)
 		return -ENOMEM;
 
-	kmemleak_not_leak(vec);
-	page->obj_cgroups = (struct obj_cgroup **) ((unsigned long)vec | 0x1UL);
+	if (cmpxchg(&page->obj_cgroups, NULL,
+		    (struct obj_cgroup **) ((unsigned long)vec | 0x1UL)))
+		kfree(vec);
+	else
+		kmemleak_not_leak(vec);
+
 	return 0;
 }
 
@@ -347,38 +291,25 @@ static inline size_t obj_full_size(struct kmem_cache *s)
 	return s->size + sizeof(struct obj_cgroup *);
 }
 
-static inline struct kmem_cache *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
-						struct obj_cgroup **objcgp,
-						size_t objects, gfp_t flags)
+static inline struct obj_cgroup *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
+							   size_t objects,
+							   gfp_t flags)
 {
-	struct kmem_cache *cachep;
 	struct obj_cgroup *objcg;
 
 	if (memcg_kmem_bypass())
-		return s;
-
-	cachep = READ_ONCE(s->memcg_params.memcg_cache);
-	if (unlikely(!cachep)) {
-		/*
-		 * If memcg cache does not exist yet, we schedule it's
-		 * asynchronous creation and let the current allocation
-		 * go through with the root cache.
-		 */
-		queue_work(system_wq, &s->memcg_params.work);
-		return s;
-	}
+		return NULL;
 
 	objcg = get_obj_cgroup_from_current();
 	if (!objcg)
-		return s;
+		return NULL;
 
 	if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s))) {
 		obj_cgroup_put(objcg);
-		cachep = NULL;
+		return NULL;
 	}
 
-	*objcgp = objcg;
-	return cachep;
+	return objcg;
 }
 
 static inline void mod_objcg_state(struct obj_cgroup *objcg,
@@ -397,15 +328,27 @@ static inline void mod_objcg_state(struct obj_cgroup *objcg,
 
 static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
 					      struct obj_cgroup *objcg,
-					      size_t size, void **p)
+					      gfp_t flags, size_t size,
+					      void **p)
 {
 	struct page *page;
 	unsigned long off;
 	size_t i;
 
+	if (!objcg)
+		return;
+
+	flags &= ~__GFP_ACCOUNT;
 	for (i = 0; i < size; i++) {
 		if (likely(p[i])) {
 			page = virt_to_head_page(p[i]);
+
+			if (!page_has_obj_cgroups(page) &&
+			    memcg_alloc_page_obj_cgroups(page, s, flags)) {
+				obj_cgroup_uncharge(objcg, obj_full_size(s));
+				continue;
+			}
+
 			off = obj_to_index(s, page, p[i]);
 			obj_cgroup_get(objcg);
 			page_obj_cgroups(page)[off] = objcg;
@@ -424,13 +367,19 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page,
 	struct obj_cgroup *objcg;
 	unsigned int off;
 
-	if (!memcg_kmem_enabled() || is_root_cache(s))
+	if (!memcg_kmem_enabled())
+		return;
+
+	if (!page_has_obj_cgroups(page))
 		return;
 
 	off = obj_to_index(s, page, p);
 	objcg = page_obj_cgroups(page)[off];
 	page_obj_cgroups(page)[off] = NULL;
 
+	if (!objcg)
+		return;
+
 	obj_cgroup_uncharge(objcg, obj_full_size(s));
 	mod_objcg_state(objcg, page_pgdat(page), cache_vmstat_idx(s),
 			-obj_full_size(s));
@@ -438,35 +387,7 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page,
 	obj_cgroup_put(objcg);
 }
 
-extern void slab_init_memcg_params(struct kmem_cache *);
-
 #else /* CONFIG_MEMCG_KMEM */
-static inline bool is_root_cache(struct kmem_cache *s)
-{
-	return true;
-}
-
-static inline bool slab_equal_or_root(struct kmem_cache *s,
-				      struct kmem_cache *p)
-{
-	return s == p;
-}
-
-static inline const char *cache_name(struct kmem_cache *s)
-{
-	return s->name;
-}
-
-static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
-{
-	return s;
-}
-
-static inline struct kmem_cache *memcg_cache(struct kmem_cache *s)
-{
-	return NULL;
-}
-
 static inline bool page_has_obj_cgroups(struct page *page)
 {
 	return false;
@@ -487,16 +408,17 @@ static inline void memcg_free_page_obj_cgroups(struct page *page)
 {
 }
 
-static inline struct kmem_cache *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
-						struct obj_cgroup **objcgp,
-						size_t objects, gfp_t flags)
+static inline struct obj_cgroup *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
+							   size_t objects,
+							   gfp_t flags)
 {
 	return NULL;
 }
 
 static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
 					      struct obj_cgroup *objcg,
-					      size_t size, void **p)
+					      gfp_t flags, size_t size,
+					      void **p)
 {
 }
 
@@ -504,11 +426,6 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page,
 					void *p)
 {
 }
-
-static inline void slab_init_memcg_params(struct kmem_cache *s)
-{
-}
-
 #endif /* CONFIG_MEMCG_KMEM */
 
 static inline struct kmem_cache *virt_to_cache(const void *obj)
@@ -522,27 +439,18 @@ static inline struct kmem_cache *virt_to_cache(const void *obj)
 	return page->slab_cache;
 }
 
-static __always_inline int charge_slab_page(struct page *page,
-					    gfp_t gfp, int order,
-					    struct kmem_cache *s)
+static __always_inline void charge_slab_page(struct page *page,
+					     gfp_t gfp, int order,
+					     struct kmem_cache *s)
 {
-	if (memcg_kmem_enabled() && !is_root_cache(s)) {
-		int ret;
-
-		ret = memcg_alloc_page_obj_cgroups(page, s, gfp);
-		if (ret)
-			return ret;
-	}
-
 	mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
 			    PAGE_SIZE << order);
-	return 0;
 }
 
 static __always_inline void uncharge_slab_page(struct page *page, int order,
 					       struct kmem_cache *s)
 {
-	if (memcg_kmem_enabled() && !is_root_cache(s))
+	if (memcg_kmem_enabled())
 		memcg_free_page_obj_cgroups(page);
 
 	mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
@@ -554,12 +462,11 @@ static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
 	struct kmem_cache *cachep;
 
 	if (!IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) &&
-	    !memcg_kmem_enabled() &&
 	    !kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS))
 		return s;
 
 	cachep = virt_to_cache(x);
-	if (WARN(cachep && !slab_equal_or_root(cachep, s),
+	if (WARN(cachep && cachep != s,
 		  "%s: Wrong slab cache. %s but object is from %s\n",
 		  __func__, s->name, cachep->name))
 		print_tracking(cachep, x);
@@ -612,7 +519,7 @@ static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
 
 	if (memcg_kmem_enabled() &&
 	    ((flags & __GFP_ACCOUNT) || (s->flags & SLAB_ACCOUNT)))
-		return memcg_slab_pre_alloc_hook(s, objcgp, size, flags);
+		*objcgp = memcg_slab_pre_alloc_hook(s, size, flags);
 
 	return s;
 }
@@ -631,8 +538,8 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s,
 					 s->flags, flags);
 	}
 
-	if (memcg_kmem_enabled() && !is_root_cache(s))
-		memcg_slab_post_alloc_hook(s, objcg, size, p);
+	if (memcg_kmem_enabled())
+		memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
 }
 
 #ifndef CONFIG_SLOB
diff --git a/mm/slab_common.c b/mm/slab_common.c
index e546778030a2..a143a8c8f874 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -128,36 +128,6 @@ int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr,
 	return i;
 }
 
-#ifdef CONFIG_MEMCG_KMEM
-static void memcg_kmem_cache_create_func(struct work_struct *work)
-{
-	struct kmem_cache *cachep = container_of(work, struct kmem_cache,
-						 memcg_params.work);
-	memcg_create_kmem_cache(cachep);
-}
-
-void slab_init_memcg_params(struct kmem_cache *s)
-{
-	s->memcg_params.root_cache = NULL;
-	s->memcg_params.memcg_cache = NULL;
-	INIT_WORK(&s->memcg_params.work, memcg_kmem_cache_create_func);
-}
-
-static void init_memcg_params(struct kmem_cache *s,
-			      struct kmem_cache *root_cache)
-{
-	if (root_cache)
-		s->memcg_params.root_cache = root_cache;
-	else
-		slab_init_memcg_params(s);
-}
-#else
-static inline void init_memcg_params(struct kmem_cache *s,
-				     struct kmem_cache *root_cache)
-{
-}
-#endif /* CONFIG_MEMCG_KMEM */
-
 /*
  * Figure out what the alignment of the objects will be given a set of
  * flags, a user specified alignment and the size of the objects.
@@ -195,9 +165,6 @@ int slab_unmergeable(struct kmem_cache *s)
 	if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE))
 		return 1;
 
-	if (!is_root_cache(s))
-		return 1;
-
 	if (s->ctor)
 		return 1;
 
@@ -284,7 +251,6 @@ static struct kmem_cache *create_cache(const char *name,
 	s->useroffset = useroffset;
 	s->usersize = usersize;
 
-	init_memcg_params(s, root_cache);
 	err = __kmem_cache_create(s, flags);
 	if (err)
 		goto out_free_cache;
@@ -342,7 +308,6 @@ kmem_cache_create_usercopy(const char *name,
 
 	get_online_cpus();
 	get_online_mems();
-	memcg_get_cache_ids();
 
 	mutex_lock(&slab_mutex);
 
@@ -392,7 +357,6 @@ kmem_cache_create_usercopy(const char *name,
 out_unlock:
 	mutex_unlock(&slab_mutex);
 
-	memcg_put_cache_ids();
 	put_online_mems();
 	put_online_cpus();
 
@@ -505,87 +469,6 @@ static int shutdown_cache(struct kmem_cache *s)
 	return 0;
 }
 
-#ifdef CONFIG_MEMCG_KMEM
-/*
- * memcg_create_kmem_cache - Create a cache for non-root memory cgroups.
- * @root_cache: The parent of the new cache.
- *
- * This function attempts to create a kmem cache that will serve allocation
- * requests going all non-root memory cgroups to @root_cache. The new cache
- * inherits properties from its parent.
- */
-void memcg_create_kmem_cache(struct kmem_cache *root_cache)
-{
-	struct kmem_cache *s = NULL;
-	char *cache_name;
-
-	get_online_cpus();
-	get_online_mems();
-
-	mutex_lock(&slab_mutex);
-
-	if (root_cache->memcg_params.memcg_cache)
-		goto out_unlock;
-
-	cache_name = kasprintf(GFP_KERNEL, "%s-memcg", root_cache->name);
-	if (!cache_name)
-		goto out_unlock;
-
-	s = create_cache(cache_name, root_cache->object_size,
-			 root_cache->align,
-			 root_cache->flags & CACHE_CREATE_MASK,
-			 root_cache->useroffset, root_cache->usersize,
-			 root_cache->ctor, root_cache);
-	/*
-	 * If we could not create a memcg cache, do not complain, because
-	 * that's not critical at all as we can always proceed with the root
-	 * cache.
-	 */
-	if (IS_ERR(s)) {
-		kfree(cache_name);
-		goto out_unlock;
-	}
-
-	/*
-	 * Since readers won't lock (see memcg_slab_pre_alloc_hook()), we need a
-	 * barrier here to ensure nobody will see the kmem_cache partially
-	 * initialized.
-	 */
-	smp_wmb();
-	root_cache->memcg_params.memcg_cache = s;
-
-out_unlock:
-	mutex_unlock(&slab_mutex);
-
-	put_online_mems();
-	put_online_cpus();
-}
-
-static int shutdown_memcg_caches(struct kmem_cache *s)
-{
-	BUG_ON(!is_root_cache(s));
-
-	if (s->memcg_params.memcg_cache)
-		WARN_ON(shutdown_cache(s->memcg_params.memcg_cache));
-
-	return 0;
-}
-
-static void cancel_memcg_cache_creation(struct kmem_cache *s)
-{
-	cancel_work_sync(&s->memcg_params.work);
-}
-#else
-static inline int shutdown_memcg_caches(struct kmem_cache *s)
-{
-	return 0;
-}
-
-static inline void cancel_memcg_cache_creation(struct kmem_cache *s)
-{
-}
-#endif /* CONFIG_MEMCG_KMEM */
-
 void slab_kmem_cache_release(struct kmem_cache *s)
 {
 	__kmem_cache_release(s);
@@ -600,8 +483,6 @@ void kmem_cache_destroy(struct kmem_cache *s)
 	if (unlikely(!s))
 		return;
 
-	cancel_memcg_cache_creation(s);
-
 	get_online_cpus();
 	get_online_mems();
 
@@ -611,10 +492,7 @@ void kmem_cache_destroy(struct kmem_cache *s)
 	if (s->refcount)
 		goto out_unlock;
 
-	err = shutdown_memcg_caches(s);
-	if (!err)
-		err = shutdown_cache(s);
-
+	err = shutdown_cache(s);
 	if (err) {
 		pr_err("kmem_cache_destroy %s: Slab cache still has objects\n",
 		       s->name);
@@ -651,33 +529,6 @@ int kmem_cache_shrink(struct kmem_cache *cachep)
 }
 EXPORT_SYMBOL(kmem_cache_shrink);
 
-/**
- * kmem_cache_shrink_all - shrink root and memcg caches
- * @s: The cache pointer
- */
-void kmem_cache_shrink_all(struct kmem_cache *s)
-{
-	struct kmem_cache *c;
-
-	if (!IS_ENABLED(CONFIG_MEMCG_KMEM) || !is_root_cache(s)) {
-		kmem_cache_shrink(s);
-		return;
-	}
-
-	get_online_cpus();
-	get_online_mems();
-	kasan_cache_shrink(s);
-	__kmem_cache_shrink(s);
-
-	c = memcg_cache(s);
-	if (c) {
-		kasan_cache_shrink(c);
-		__kmem_cache_shrink(c);
-	}
-	put_online_mems();
-	put_online_cpus();
-}
-
 bool slab_is_available(void)
 {
 	return slab_state >= UP;
@@ -706,8 +557,6 @@ void __init create_boot_cache(struct kmem_cache *s, const char *name,
 	s->useroffset = useroffset;
 	s->usersize = usersize;
 
-	slab_init_memcg_params(s);
-
 	err = __kmem_cache_create(s, flags);
 
 	if (err)
@@ -1081,25 +930,6 @@ void slab_stop(struct seq_file *m, void *p)
 	mutex_unlock(&slab_mutex);
 }
 
-static void
-memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info)
-{
-	struct kmem_cache *c;
-	struct slabinfo sinfo;
-
-	c = memcg_cache(s);
-	if (c) {
-		memset(&sinfo, 0, sizeof(sinfo));
-		get_slabinfo(c, &sinfo);
-
-		info->active_slabs += sinfo.active_slabs;
-		info->num_slabs += sinfo.num_slabs;
-		info->shared_avail += sinfo.shared_avail;
-		info->active_objs += sinfo.active_objs;
-		info->num_objs += sinfo.num_objs;
-	}
-}
-
 static void cache_show(struct kmem_cache *s, struct seq_file *m)
 {
 	struct slabinfo sinfo;
@@ -1107,10 +937,8 @@ static void cache_show(struct kmem_cache *s, struct seq_file *m)
 	memset(&sinfo, 0, sizeof(sinfo));
 	get_slabinfo(s, &sinfo);
 
-	memcg_accumulate_slabinfo(s, &sinfo);
-
 	seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
-		   cache_name(s), sinfo.active_objs, sinfo.num_objs, s->size,
+		   s->name, sinfo.active_objs, sinfo.num_objs, s->size,
 		   sinfo.objects_per_slab, (1 << sinfo.cache_order));
 
 	seq_printf(m, " : tunables %4u %4u %4u",
@@ -1127,8 +955,7 @@ static int slab_show(struct seq_file *m, void *p)
 
 	if (p == slab_caches.next)
 		print_slabinfo_header(m);
-	if (is_root_cache(s))
-		cache_show(s, m);
+	cache_show(s, m);
 	return 0;
 }
 
@@ -1153,13 +980,13 @@ void dump_unreclaimable_slab(void)
 	pr_info("Name                      Used          Total\n");
 
 	list_for_each_entry_safe(s, s2, &slab_caches, list) {
-		if (!is_root_cache(s) || (s->flags & SLAB_RECLAIM_ACCOUNT))
+		if (s->flags & SLAB_RECLAIM_ACCOUNT)
 			continue;
 
 		get_slabinfo(s, &sinfo);
 
 		if (sinfo.num_objs > 0)
-			pr_info("%-17s %10luKB %10luKB\n", cache_name(s),
+			pr_info("%-17s %10luKB %10luKB\n", s->name,
 				(sinfo.active_objs * s->size) / 1024,
 				(sinfo.num_objs * s->size) / 1024);
 	}
@@ -1218,53 +1045,6 @@ static int __init slab_proc_init(void)
 }
 module_init(slab_proc_init);
 
-#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_MEMCG_KMEM)
-/*
- * Display information about kmem caches that have memcg cache.
- */
-static int memcg_slabinfo_show(struct seq_file *m, void *unused)
-{
-	struct kmem_cache *s, *c;
-	struct slabinfo sinfo;
-
-	mutex_lock(&slab_mutex);
-	seq_puts(m, "# <name> <css_id[:dead|deact]> <active_objs> <num_objs>");
-	seq_puts(m, " <active_slabs> <num_slabs>\n");
-	list_for_each_entry(s, &slab_caches, list) {
-		/*
-		 * Skip kmem caches that don't have the memcg cache.
-		 */
-		if (!s->memcg_params.memcg_cache)
-			continue;
-
-		memset(&sinfo, 0, sizeof(sinfo));
-		get_slabinfo(s, &sinfo);
-		seq_printf(m, "%-17s root       %6lu %6lu %6lu %6lu\n",
-			   cache_name(s), sinfo.active_objs, sinfo.num_objs,
-			   sinfo.active_slabs, sinfo.num_slabs);
-
-		c = s->memcg_params.memcg_cache;
-		memset(&sinfo, 0, sizeof(sinfo));
-		get_slabinfo(c, &sinfo);
-		seq_printf(m, "%-17s %4d %6lu %6lu %6lu %6lu\n",
-			   cache_name(c), root_mem_cgroup->css.id,
-			   sinfo.active_objs, sinfo.num_objs,
-			   sinfo.active_slabs, sinfo.num_slabs);
-	}
-	mutex_unlock(&slab_mutex);
-	return 0;
-}
-DEFINE_SHOW_ATTRIBUTE(memcg_slabinfo);
-
-static int __init memcg_slabinfo_init(void)
-{
-	debugfs_create_file("memcg_slabinfo", S_IFREG | S_IRUGO,
-			    NULL, NULL, &memcg_slabinfo_fops);
-	return 0;
-}
-
-late_initcall(memcg_slabinfo_init);
-#endif /* CONFIG_DEBUG_FS && CONFIG_MEMCG_KMEM */
 #endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */
 
 static __always_inline void *__do_krealloc(const void *p, size_t new_size,
diff --git a/mm/slub.c b/mm/slub.c
index 7a5d6861b088..0a2a37fdcc52 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -218,14 +218,10 @@ enum track_item { TRACK_ALLOC, TRACK_FREE };
 #ifdef CONFIG_SYSFS
 static int sysfs_slab_add(struct kmem_cache *);
 static int sysfs_slab_alias(struct kmem_cache *, const char *);
-static void memcg_propagate_slab_attrs(struct kmem_cache *s);
-static void sysfs_slab_remove(struct kmem_cache *s);
 #else
 static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
 							{ return 0; }
-static inline void memcg_propagate_slab_attrs(struct kmem_cache *s) { }
-static inline void sysfs_slab_remove(struct kmem_cache *s) { }
 #endif
 
 static inline void stat(const struct kmem_cache *s, enum stat_item si)
@@ -1623,10 +1619,8 @@ static inline struct page *alloc_slab_page(struct kmem_cache *s,
 	else
 		page = __alloc_pages_node(node, flags, order);
 
-	if (page && charge_slab_page(page, flags, order, s)) {
-		__free_pages(page, order);
-		page = NULL;
-	}
+	if (page)
+		charge_slab_page(page, flags, order, s);
 
 	return page;
 }
@@ -3924,7 +3918,6 @@ int __kmem_cache_shutdown(struct kmem_cache *s)
 		if (n->nr_partial || slabs_node(s, node))
 			return 1;
 	}
-	sysfs_slab_remove(s);
 	return 0;
 }
 
@@ -4362,7 +4355,6 @@ static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
 			p->slab_cache = s;
 #endif
 	}
-	slab_init_memcg_params(s);
 	list_add(&s->list, &slab_caches);
 	return s;
 }
@@ -4418,7 +4410,7 @@ struct kmem_cache *
 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
 		   slab_flags_t flags, void (*ctor)(void *))
 {
-	struct kmem_cache *s, *c;
+	struct kmem_cache *s;
 
 	s = find_mergeable(size, align, flags, name, ctor);
 	if (s) {
@@ -4431,12 +4423,6 @@ __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
 		s->object_size = max(s->object_size, size);
 		s->inuse = max(s->inuse, ALIGN(size, sizeof(void *)));
 
-		c = memcg_cache(s);
-		if (c) {
-			c->object_size = s->object_size;
-			c->inuse = max(c->inuse, ALIGN(size, sizeof(void *)));
-		}
-
 		if (sysfs_slab_alias(s, name)) {
 			s->refcount--;
 			s = NULL;
@@ -4458,7 +4444,6 @@ int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
 	if (slab_state <= UP)
 		return 0;
 
-	memcg_propagate_slab_attrs(s);
 	err = sysfs_slab_add(s);
 	if (err)
 		__kmem_cache_release(s);
@@ -5316,7 +5301,7 @@ static ssize_t shrink_store(struct kmem_cache *s,
 			const char *buf, size_t length)
 {
 	if (buf[0] == '1')
-		kmem_cache_shrink_all(s);
+		kmem_cache_shrink(s);
 	else
 		return -EINVAL;
 	return length;
@@ -5540,99 +5525,9 @@ static ssize_t slab_attr_store(struct kobject *kobj,
 		return -EIO;
 
 	err = attribute->store(s, buf, len);
-#ifdef CONFIG_MEMCG
-	if (slab_state >= FULL && err >= 0 && is_root_cache(s)) {
-		struct kmem_cache *c;
-
-		mutex_lock(&slab_mutex);
-		if (s->max_attr_size < len)
-			s->max_attr_size = len;
-
-		/*
-		 * This is a best effort propagation, so this function's return
-		 * value will be determined by the parent cache only. This is
-		 * basically because not all attributes will have a well
-		 * defined semantics for rollbacks - most of the actions will
-		 * have permanent effects.
-		 *
-		 * Returning the error value of any of the children that fail
-		 * is not 100 % defined, in the sense that users seeing the
-		 * error code won't be able to know anything about the state of
-		 * the cache.
-		 *
-		 * Only returning the error code for the parent cache at least
-		 * has well defined semantics. The cache being written to
-		 * directly either failed or succeeded, in which case we loop
-		 * through the descendants with best-effort propagation.
-		 */
-		c = memcg_cache(s);
-		if (c)
-			attribute->store(c, buf, len);
-		mutex_unlock(&slab_mutex);
-	}
-#endif
 	return err;
 }
 
-static void memcg_propagate_slab_attrs(struct kmem_cache *s)
-{
-#ifdef CONFIG_MEMCG
-	int i;
-	char *buffer = NULL;
-	struct kmem_cache *root_cache;
-
-	if (is_root_cache(s))
-		return;
-
-	root_cache = s->memcg_params.root_cache;
-
-	/*
-	 * This mean this cache had no attribute written. Therefore, no point
-	 * in copying default values around
-	 */
-	if (!root_cache->max_attr_size)
-		return;
-
-	for (i = 0; i < ARRAY_SIZE(slab_attrs); i++) {
-		char mbuf[64];
-		char *buf;
-		struct slab_attribute *attr = to_slab_attr(slab_attrs[i]);
-		ssize_t len;
-
-		if (!attr || !attr->store || !attr->show)
-			continue;
-
-		/*
-		 * It is really bad that we have to allocate here, so we will
-		 * do it only as a fallback. If we actually allocate, though,
-		 * we can just use the allocated buffer until the end.
-		 *
-		 * Most of the slub attributes will tend to be very small in
-		 * size, but sysfs allows buffers up to a page, so they can
-		 * theoretically happen.
-		 */
-		if (buffer)
-			buf = buffer;
-		else if (root_cache->max_attr_size < ARRAY_SIZE(mbuf) &&
-			 !IS_ENABLED(CONFIG_SLUB_STATS))
-			buf = mbuf;
-		else {
-			buffer = (char *) get_zeroed_page(GFP_KERNEL);
-			if (WARN_ON(!buffer))
-				continue;
-			buf = buffer;
-		}
-
-		len = attr->show(root_cache, buf);
-		if (len > 0)
-			attr->store(s, buf, len);
-	}
-
-	if (buffer)
-		free_page((unsigned long)buffer);
-#endif	/* CONFIG_MEMCG */
-}
-
 static void kmem_cache_release(struct kobject *k)
 {
 	slab_kmem_cache_release(to_slab(k));
@@ -5652,10 +5547,6 @@ static struct kset *slab_kset;
 
 static inline struct kset *cache_kset(struct kmem_cache *s)
 {
-#ifdef CONFIG_MEMCG
-	if (!is_root_cache(s))
-		return s->memcg_params.root_cache->memcg_kset;
-#endif
 	return slab_kset;
 }
 
@@ -5698,27 +5589,6 @@ static char *create_unique_id(struct kmem_cache *s)
 	return name;
 }
 
-static void sysfs_slab_remove_workfn(struct work_struct *work)
-{
-	struct kmem_cache *s =
-		container_of(work, struct kmem_cache, kobj_remove_work);
-
-	if (!s->kobj.state_in_sysfs)
-		/*
-		 * For a memcg cache, this may be called during
-		 * deactivation and again on shutdown.  Remove only once.
-		 * A cache is never shut down before deactivation is
-		 * complete, so no need to worry about synchronization.
-		 */
-		goto out;
-
-#ifdef CONFIG_MEMCG
-	kset_unregister(s->memcg_kset);
-#endif
-out:
-	kobject_put(&s->kobj);
-}
-
 static int sysfs_slab_add(struct kmem_cache *s)
 {
 	int err;
@@ -5726,8 +5596,6 @@ static int sysfs_slab_add(struct kmem_cache *s)
 	struct kset *kset = cache_kset(s);
 	int unmergeable = slab_unmergeable(s);
 
-	INIT_WORK(&s->kobj_remove_work, sysfs_slab_remove_workfn);
-
 	if (!kset) {
 		kobject_init(&s->kobj, &slab_ktype);
 		return 0;
@@ -5764,16 +5632,6 @@ static int sysfs_slab_add(struct kmem_cache *s)
 	if (err)
 		goto out_del_kobj;
 
-#ifdef CONFIG_MEMCG
-	if (is_root_cache(s) && memcg_sysfs_enabled) {
-		s->memcg_kset = kset_create_and_add("cgroup", NULL, &s->kobj);
-		if (!s->memcg_kset) {
-			err = -ENOMEM;
-			goto out_del_kobj;
-		}
-	}
-#endif
-
 	if (!unmergeable) {
 		/* Setup first alias */
 		sysfs_slab_alias(s, s->name);
@@ -5787,19 +5645,6 @@ static int sysfs_slab_add(struct kmem_cache *s)
 	goto out;
 }
 
-static void sysfs_slab_remove(struct kmem_cache *s)
-{
-	if (slab_state < FULL)
-		/*
-		 * Sysfs has not been setup yet so no need to remove the
-		 * cache from sysfs.
-		 */
-		return;
-
-	kobject_get(&s->kobj);
-	schedule_work(&s->kobj_remove_work);
-}
-
 void sysfs_slab_unlink(struct kmem_cache *s)
 {
 	if (slab_state >= FULL)
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 18/19] kselftests: cgroup: add kernel memory accounting tests
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
                   ` (16 preceding siblings ...)
  2020-06-23  1:58 ` [PATCH v7 17/19] mm: memcg/slab: use a single set of kmem_caches for all allocations Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23  1:58 ` [PATCH v7 19/19] tools/cgroup: add memcg_slabinfo.py tool Roman Gushchin
  2020-06-23 13:53 ` [PATCH v7 00/19] The new cgroup slab memory controller Vlastimil Babka
  19 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

Add some tests to cover the kernel memory accounting functionality.  These
are covering some issues (and changes) we had recently.

1) A test which allocates a lot of negative dentries, checks memcg slab
   statistics, creates memory pressure by setting memory.max to some low
   value and checks that some number of slabs was reclaimed.

2) A test which covers side effects of memcg destruction: it creates
   and destroys a large number of sub-cgroups, each containing a
   multi-threaded workload which allocates and releases some kernel
   memory.  Then it checks that the charge ans memory.stats do add up on
   the parent level.

3) A test which reads /proc/kpagecgroup and implicitly checks that it
   doesn't crash the system.

4) A test which spawns a large number of threads and checks that the
   kernel stacks accounting works as expected.

5) A test which checks that living charged slab objects are not
   preventing the memory cgroup from being released after being deleted by
   a user.

Signed-off-by: Roman Gushchin <guro@fb.com>
---
 tools/testing/selftests/cgroup/.gitignore  |   1 +
 tools/testing/selftests/cgroup/Makefile    |   2 +
 tools/testing/selftests/cgroup/test_kmem.c | 382 +++++++++++++++++++++
 3 files changed, 385 insertions(+)
 create mode 100644 tools/testing/selftests/cgroup/test_kmem.c

diff --git a/tools/testing/selftests/cgroup/.gitignore b/tools/testing/selftests/cgroup/.gitignore
index aa6de65b0838..84cfcabea838 100644
--- a/tools/testing/selftests/cgroup/.gitignore
+++ b/tools/testing/selftests/cgroup/.gitignore
@@ -2,3 +2,4 @@
 test_memcontrol
 test_core
 test_freezer
+test_kmem
\ No newline at end of file
diff --git a/tools/testing/selftests/cgroup/Makefile b/tools/testing/selftests/cgroup/Makefile
index 967f268fde74..f027d933595b 100644
--- a/tools/testing/selftests/cgroup/Makefile
+++ b/tools/testing/selftests/cgroup/Makefile
@@ -6,11 +6,13 @@ all:
 TEST_FILES     := with_stress.sh
 TEST_PROGS     := test_stress.sh
 TEST_GEN_PROGS = test_memcontrol
+TEST_GEN_PROGS += test_kmem
 TEST_GEN_PROGS += test_core
 TEST_GEN_PROGS += test_freezer
 
 include ../lib.mk
 
 $(OUTPUT)/test_memcontrol: cgroup_util.c ../clone3/clone3_selftests.h
+$(OUTPUT)/test_kmem: cgroup_util.c ../clone3/clone3_selftests.h
 $(OUTPUT)/test_core: cgroup_util.c ../clone3/clone3_selftests.h
 $(OUTPUT)/test_freezer: cgroup_util.c ../clone3/clone3_selftests.h
diff --git a/tools/testing/selftests/cgroup/test_kmem.c b/tools/testing/selftests/cgroup/test_kmem.c
new file mode 100644
index 000000000000..5224dae216e5
--- /dev/null
+++ b/tools/testing/selftests/cgroup/test_kmem.c
@@ -0,0 +1,382 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+
+#include <linux/limits.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <sys/wait.h>
+#include <errno.h>
+#include <sys/sysinfo.h>
+#include <pthread.h>
+
+#include "../kselftest.h"
+#include "cgroup_util.h"
+
+
+static int alloc_dcache(const char *cgroup, void *arg)
+{
+	unsigned long i;
+	struct stat st;
+	char buf[128];
+
+	for (i = 0; i < (unsigned long)arg; i++) {
+		snprintf(buf, sizeof(buf),
+			"/something-non-existent-with-a-long-name-%64lu-%d",
+			 i, getpid());
+		stat(buf, &st);
+	}
+
+	return 0;
+}
+
+/*
+ * This test allocates 100000 of negative dentries with long names.
+ * Then it checks that "slab" in memory.stat is larger than 1M.
+ * Then it sets memory.high to 1M and checks that at least 1/2
+ * of slab memory has been reclaimed.
+ */
+static int test_kmem_basic(const char *root)
+{
+	int ret = KSFT_FAIL;
+	char *cg = NULL;
+	long slab0, slab1, current;
+
+	cg = cg_name(root, "kmem_basic_test");
+	if (!cg)
+		goto cleanup;
+
+	if (cg_create(cg))
+		goto cleanup;
+
+	if (cg_run(cg, alloc_dcache, (void *)100000))
+		goto cleanup;
+
+	slab0 = cg_read_key_long(cg, "memory.stat", "slab ");
+	if (slab0 < (1 << 20))
+		goto cleanup;
+
+	cg_write(cg, "memory.high", "1M");
+	slab1 = cg_read_key_long(cg, "memory.stat", "slab ");
+	if (slab1 <= 0)
+		goto cleanup;
+
+	current = cg_read_long(cg, "memory.current");
+	if (current <= 0)
+		goto cleanup;
+
+	if (slab1 < slab0 / 2 && current < slab0 / 2)
+		ret = KSFT_PASS;
+cleanup:
+	cg_destroy(cg);
+	free(cg);
+
+	return ret;
+}
+
+static void *alloc_kmem_fn(void *arg)
+{
+	alloc_dcache(NULL, (void *)100);
+	return NULL;
+}
+
+static int alloc_kmem_smp(const char *cgroup, void *arg)
+{
+	int nr_threads = 2 * get_nprocs();
+	pthread_t *tinfo;
+	unsigned long i;
+	int ret = -1;
+
+	tinfo = calloc(nr_threads, sizeof(pthread_t));
+	if (tinfo == NULL)
+		return -1;
+
+	for (i = 0; i < nr_threads; i++) {
+		if (pthread_create(&tinfo[i], NULL, &alloc_kmem_fn,
+				   (void *)i)) {
+			free(tinfo);
+			return -1;
+		}
+	}
+
+	for (i = 0; i < nr_threads; i++) {
+		ret = pthread_join(tinfo[i], NULL);
+		if (ret)
+			break;
+	}
+
+	free(tinfo);
+	return ret;
+}
+
+static int cg_run_in_subcgroups(const char *parent,
+				int (*fn)(const char *cgroup, void *arg),
+				void *arg, int times)
+{
+	char *child;
+	int i;
+
+	for (i = 0; i < times; i++) {
+		child = cg_name_indexed(parent, "child", i);
+		if (!child)
+			return -1;
+
+		if (cg_create(child)) {
+			cg_destroy(child);
+			free(child);
+			return -1;
+		}
+
+		if (cg_run(child, fn, NULL)) {
+			cg_destroy(child);
+			free(child);
+			return -1;
+		}
+
+		cg_destroy(child);
+		free(child);
+	}
+
+	return 0;
+}
+
+/*
+ * The test creates and destroys a large number of cgroups. In each cgroup it
+ * allocates some slab memory (mostly negative dentries) using 2 * NR_CPUS
+ * threads. Then it checks the sanity of numbers on the parent level:
+ * the total size of the cgroups should be roughly equal to
+ * anon + file + slab + kernel_stack.
+ */
+static int test_kmem_memcg_deletion(const char *root)
+{
+	long current, slab, anon, file, kernel_stack, sum;
+	int ret = KSFT_FAIL;
+	char *parent;
+
+	parent = cg_name(root, "kmem_memcg_deletion_test");
+	if (!parent)
+		goto cleanup;
+
+	if (cg_create(parent))
+		goto cleanup;
+
+	if (cg_write(parent, "cgroup.subtree_control", "+memory"))
+		goto cleanup;
+
+	if (cg_run_in_subcgroups(parent, alloc_kmem_smp, NULL, 100))
+		goto cleanup;
+
+	current = cg_read_long(parent, "memory.current");
+	slab = cg_read_key_long(parent, "memory.stat", "slab ");
+	anon = cg_read_key_long(parent, "memory.stat", "anon ");
+	file = cg_read_key_long(parent, "memory.stat", "file ");
+	kernel_stack = cg_read_key_long(parent, "memory.stat", "kernel_stack ");
+	if (current < 0 || slab < 0 || anon < 0 || file < 0 ||
+	    kernel_stack < 0)
+		goto cleanup;
+
+	sum = slab + anon + file + kernel_stack;
+	if (abs(sum - current) < 4096 * 32 * 2 * get_nprocs()) {
+		ret = KSFT_PASS;
+	} else {
+		printf("memory.current = %ld\n", current);
+		printf("slab + anon + file + kernel_stack = %ld\n", sum);
+		printf("slab = %ld\n", slab);
+		printf("anon = %ld\n", anon);
+		printf("file = %ld\n", file);
+		printf("kernel_stack = %ld\n", kernel_stack);
+	}
+
+cleanup:
+	cg_destroy(parent);
+	free(parent);
+
+	return ret;
+}
+
+/*
+ * The test reads the entire /proc/kpagecgroup. If the operation went
+ * successfully (and the kernel didn't panic), the test is treated as passed.
+ */
+static int test_kmem_proc_kpagecgroup(const char *root)
+{
+	unsigned long buf[128];
+	int ret = KSFT_FAIL;
+	ssize_t len;
+	int fd;
+
+	fd = open("/proc/kpagecgroup", O_RDONLY);
+	if (fd < 0)
+		return ret;
+
+	do {
+		len = read(fd, buf, sizeof(buf));
+	} while (len > 0);
+
+	if (len == 0)
+		ret = KSFT_PASS;
+
+	close(fd);
+	return ret;
+}
+
+static void *pthread_wait_fn(void *arg)
+{
+	sleep(100);
+	return NULL;
+}
+
+static int spawn_1000_threads(const char *cgroup, void *arg)
+{
+	int nr_threads = 1000;
+	pthread_t *tinfo;
+	unsigned long i;
+	long stack;
+	int ret = -1;
+
+	tinfo = calloc(nr_threads, sizeof(pthread_t));
+	if (tinfo == NULL)
+		return -1;
+
+	for (i = 0; i < nr_threads; i++) {
+		if (pthread_create(&tinfo[i], NULL, &pthread_wait_fn,
+				   (void *)i)) {
+			free(tinfo);
+			return(-1);
+		}
+	}
+
+	stack = cg_read_key_long(cgroup, "memory.stat", "kernel_stack ");
+	if (stack >= 4096 * 1000)
+		ret = 0;
+
+	free(tinfo);
+	return ret;
+}
+
+/*
+ * The test spawns a process, which spawns 1000 threads. Then it checks
+ * that memory.stat's kernel_stack is at least 1000 pages large.
+ */
+static int test_kmem_kernel_stacks(const char *root)
+{
+	int ret = KSFT_FAIL;
+	char *cg = NULL;
+
+	cg = cg_name(root, "kmem_kernel_stacks_test");
+	if (!cg)
+		goto cleanup;
+
+	if (cg_create(cg))
+		goto cleanup;
+
+	if (cg_run(cg, spawn_1000_threads, NULL))
+		goto cleanup;
+
+	ret = KSFT_PASS;
+cleanup:
+	cg_destroy(cg);
+	free(cg);
+
+	return ret;
+}
+
+/*
+ * This test sequentionally creates 30 child cgroups, allocates some
+ * kernel memory in each of them, and deletes them. Then it checks
+ * that the number of dying cgroups on the parent level is 0.
+ */
+static int test_kmem_dead_cgroups(const char *root)
+{
+	int ret = KSFT_FAIL;
+	char *parent;
+	long dead;
+	int i;
+
+	parent = cg_name(root, "kmem_dead_cgroups_test");
+	if (!parent)
+		goto cleanup;
+
+	if (cg_create(parent))
+		goto cleanup;
+
+	if (cg_write(parent, "cgroup.subtree_control", "+memory"))
+		goto cleanup;
+
+	if (cg_run_in_subcgroups(parent, alloc_dcache, (void *)100, 30))
+		goto cleanup;
+
+	for (i = 0; i < 5; i++) {
+		dead = cg_read_key_long(parent, "cgroup.stat",
+					"nr_dying_descendants ");
+		if (dead == 0) {
+			ret = KSFT_PASS;
+			break;
+		}
+		/*
+		 * Reclaiming cgroups might take some time,
+		 * let's wait a bit and repeat.
+		 */
+		sleep(1);
+	}
+
+cleanup:
+	cg_destroy(parent);
+	free(parent);
+
+	return ret;
+}
+
+#define T(x) { x, #x }
+struct kmem_test {
+	int (*fn)(const char *root);
+	const char *name;
+} tests[] = {
+	T(test_kmem_basic),
+	T(test_kmem_memcg_deletion),
+	T(test_kmem_proc_kpagecgroup),
+	T(test_kmem_kernel_stacks),
+	T(test_kmem_dead_cgroups),
+};
+#undef T
+
+int main(int argc, char **argv)
+{
+	char root[PATH_MAX];
+	int i, ret = EXIT_SUCCESS;
+
+	if (cg_find_unified_root(root, sizeof(root)))
+		ksft_exit_skip("cgroup v2 isn't mounted\n");
+
+	/*
+	 * Check that memory controller is available:
+	 * memory is listed in cgroup.controllers
+	 */
+	if (cg_read_strstr(root, "cgroup.controllers", "memory"))
+		ksft_exit_skip("memory controller isn't available\n");
+
+	if (cg_read_strstr(root, "cgroup.subtree_control", "memory"))
+		if (cg_write(root, "cgroup.subtree_control", "+memory"))
+			ksft_exit_skip("Failed to set memory controller\n");
+
+	for (i = 0; i < ARRAY_SIZE(tests); i++) {
+		switch (tests[i].fn(root)) {
+		case KSFT_PASS:
+			ksft_test_result_pass("%s\n", tests[i].name);
+			break;
+		case KSFT_SKIP:
+			ksft_test_result_skip("%s\n", tests[i].name);
+			break;
+		default:
+			ret = EXIT_FAILURE;
+			ksft_test_result_fail("%s\n", tests[i].name);
+			break;
+		}
+	}
+
+	return ret;
+}
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* [PATCH v7 19/19] tools/cgroup: add memcg_slabinfo.py tool
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
                   ` (17 preceding siblings ...)
  2020-06-23  1:58 ` [PATCH v7 18/19] kselftests: cgroup: add kernel memory accounting tests Roman Gushchin
@ 2020-06-23  1:58 ` Roman Gushchin
  2020-06-23 13:53 ` [PATCH v7 00/19] The new cgroup slab memory controller Vlastimil Babka
  19 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23  1:58 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin,
	Tejun Heo

Add a drgn-based tool to display slab information for a given memcg.  Can
replace cgroup v1 memory.kmem.slabinfo interface on cgroup v2, but in a
more flexiable way.

Currently supports only SLUB configuration, but SLAB can be trivially
added later.

Output example:
$ sudo ./tools/cgroup/memcg_slabinfo.py /sys/fs/cgroup/user.slice/user-111017.slice/user\@111017.service
shmem_inode_cache     92     92    704   46    8 : tunables    0    0    0 : slabdata      2      2      0
eventpoll_pwq         56     56     72   56    1 : tunables    0    0    0 : slabdata      1      1      0
eventpoll_epi         32     32    128   32    1 : tunables    0    0    0 : slabdata      1      1      0
kmalloc-8              0      0      8  512    1 : tunables    0    0    0 : slabdata      0      0      0
kmalloc-96             0      0     96   42    1 : tunables    0    0    0 : slabdata      0      0      0
kmalloc-2048           0      0   2048   16    8 : tunables    0    0    0 : slabdata      0      0      0
kmalloc-64           128    128     64   64    1 : tunables    0    0    0 : slabdata      2      2      0
mm_struct            160    160   1024   32    8 : tunables    0    0    0 : slabdata      5      5      0
signal_cache          96     96   1024   32    8 : tunables    0    0    0 : slabdata      3      3      0
sighand_cache         45     45   2112   15    8 : tunables    0    0    0 : slabdata      3      3      0
files_cache          138    138    704   46    8 : tunables    0    0    0 : slabdata      3      3      0
task_delay_info      153    153     80   51    1 : tunables    0    0    0 : slabdata      3      3      0
task_struct           27     27   3520    9    8 : tunables    0    0    0 : slabdata      3      3      0
radix_tree_node       56     56    584   28    4 : tunables    0    0    0 : slabdata      2      2      0
btrfs_inode          140    140   1136   28    8 : tunables    0    0    0 : slabdata      5      5      0
kmalloc-1024          64     64   1024   32    8 : tunables    0    0    0 : slabdata      2      2      0
kmalloc-192           84     84    192   42    2 : tunables    0    0    0 : slabdata      2      2      0
inode_cache           54     54    600   27    4 : tunables    0    0    0 : slabdata      2      2      0
kmalloc-128            0      0    128   32    1 : tunables    0    0    0 : slabdata      0      0      0
kmalloc-512           32     32    512   32    4 : tunables    0    0    0 : slabdata      1      1      0
skbuff_head_cache     32     32    256   32    2 : tunables    0    0    0 : slabdata      1      1      0
sock_inode_cache      46     46    704   46    8 : tunables    0    0    0 : slabdata      1      1      0
cred_jar             378    378    192   42    2 : tunables    0    0    0 : slabdata      9      9      0
proc_inode_cache      96     96    672   24    4 : tunables    0    0    0 : slabdata      4      4      0
dentry               336    336    192   42    2 : tunables    0    0    0 : slabdata      8      8      0
filp                 697    864    256   32    2 : tunables    0    0    0 : slabdata     27     27      0
anon_vma             644    644     88   46    1 : tunables    0    0    0 : slabdata     14     14      0
pid                 1408   1408     64   64    1 : tunables    0    0    0 : slabdata     22     22      0
vm_area_struct      1200   1200    200   40    2 : tunables    0    0    0 : slabdata     30     30      0

Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Tejun Heo <tj@kernel.org>
---
 tools/cgroup/memcg_slabinfo.py | 226 +++++++++++++++++++++++++++++++++
 1 file changed, 226 insertions(+)
 create mode 100644 tools/cgroup/memcg_slabinfo.py

diff --git a/tools/cgroup/memcg_slabinfo.py b/tools/cgroup/memcg_slabinfo.py
new file mode 100644
index 000000000000..c4225ed63565
--- /dev/null
+++ b/tools/cgroup/memcg_slabinfo.py
@@ -0,0 +1,226 @@
+#!/usr/bin/env drgn
+#
+# Copyright (C) 2020 Roman Gushchin <guro@fb.com>
+# Copyright (C) 2020 Facebook
+
+from os import stat
+import argparse
+import sys
+
+from drgn.helpers.linux import list_for_each_entry, list_empty
+from drgn.helpers.linux import for_each_page
+from drgn.helpers.linux.cpumask import for_each_online_cpu
+from drgn.helpers.linux.percpu import per_cpu_ptr
+from drgn import container_of, FaultError, Object
+
+
+DESC = """
+This is a drgn script to provide slab statistics for memory cgroups.
+It supports cgroup v2 and v1 and can emulate memory.kmem.slabinfo
+interface of cgroup v1.
+For drgn, visit https://github.com/osandov/drgn.
+"""
+
+
+MEMCGS = {}
+
+OO_SHIFT = 16
+OO_MASK = ((1 << OO_SHIFT) - 1)
+
+
+def err(s):
+    print('slabinfo.py: error: %s' % s, file=sys.stderr, flush=True)
+    sys.exit(1)
+
+
+def find_memcg_ids(css=prog['root_mem_cgroup'].css, prefix=''):
+    if not list_empty(css.children.address_of_()):
+        for css in list_for_each_entry('struct cgroup_subsys_state',
+                                       css.children.address_of_(),
+                                       'sibling'):
+            name = prefix + '/' + css.cgroup.kn.name.string_().decode('utf-8')
+            memcg = container_of(css, 'struct mem_cgroup', 'css')
+            MEMCGS[css.cgroup.kn.id.value_()] = memcg
+            find_memcg_ids(css, name)
+
+
+def is_root_cache(s):
+    try:
+        return False if s.memcg_params.root_cache else True
+    except AttributeError:
+        return True
+
+
+def cache_name(s):
+    if is_root_cache(s):
+        return s.name.string_().decode('utf-8')
+    else:
+        return s.memcg_params.root_cache.name.string_().decode('utf-8')
+
+
+# SLUB
+
+def oo_order(s):
+    return s.oo.x >> OO_SHIFT
+
+
+def oo_objects(s):
+    return s.oo.x & OO_MASK
+
+
+def count_partial(n, fn):
+    nr_pages = 0
+    for page in list_for_each_entry('struct page', n.partial.address_of_(),
+                                    'lru'):
+         nr_pages += fn(page)
+    return nr_pages
+
+
+def count_free(page):
+    return page.objects - page.inuse
+
+
+def slub_get_slabinfo(s, cfg):
+    nr_slabs = 0
+    nr_objs = 0
+    nr_free = 0
+
+    for node in range(cfg['nr_nodes']):
+        n = s.node[node]
+        nr_slabs += n.nr_slabs.counter.value_()
+        nr_objs += n.total_objects.counter.value_()
+        nr_free += count_partial(n, count_free)
+
+    return {'active_objs': nr_objs - nr_free,
+            'num_objs': nr_objs,
+            'active_slabs': nr_slabs,
+            'num_slabs': nr_slabs,
+            'objects_per_slab': oo_objects(s),
+            'cache_order': oo_order(s),
+            'limit': 0,
+            'batchcount': 0,
+            'shared': 0,
+            'shared_avail': 0}
+
+
+def cache_show(s, cfg, objs):
+    if cfg['allocator'] == 'SLUB':
+        sinfo = slub_get_slabinfo(s, cfg)
+    else:
+        err('SLAB isn\'t supported yet')
+
+    if cfg['shared_slab_pages']:
+        sinfo['active_objs'] = objs
+        sinfo['num_objs'] = objs
+
+    print('%-17s %6lu %6lu %6u %4u %4d'
+          ' : tunables %4u %4u %4u'
+          ' : slabdata %6lu %6lu %6lu' % (
+              cache_name(s), sinfo['active_objs'], sinfo['num_objs'],
+              s.size, sinfo['objects_per_slab'], 1 << sinfo['cache_order'],
+              sinfo['limit'], sinfo['batchcount'], sinfo['shared'],
+              sinfo['active_slabs'], sinfo['num_slabs'],
+              sinfo['shared_avail']))
+
+
+def detect_kernel_config():
+    cfg = {}
+
+    cfg['nr_nodes'] = prog['nr_online_nodes'].value_()
+
+    if prog.type('struct kmem_cache').members[1][1] == 'flags':
+        cfg['allocator'] = 'SLUB'
+    elif prog.type('struct kmem_cache').members[1][1] == 'batchcount':
+        cfg['allocator'] = 'SLAB'
+    else:
+        err('Can\'t determine the slab allocator')
+
+    cfg['shared_slab_pages'] = False
+    try:
+        if prog.type('struct obj_cgroup'):
+            cfg['shared_slab_pages'] = True
+    except:
+        pass
+
+    return cfg
+
+
+def for_each_slab_page(prog):
+    PGSlab = 1 << prog.constant('PG_slab')
+    PGHead = 1 << prog.constant('PG_head')
+
+    for page in for_each_page(prog):
+        try:
+            if page.flags.value_() & PGSlab:
+                yield page
+        except FaultError:
+            pass
+
+
+def main():
+    parser = argparse.ArgumentParser(description=DESC,
+                                     formatter_class=
+                                     argparse.RawTextHelpFormatter)
+    parser.add_argument('cgroup', metavar='CGROUP',
+                        help='Target memory cgroup')
+    args = parser.parse_args()
+
+    try:
+        cgroup_id = stat(args.cgroup).st_ino
+        find_memcg_ids()
+        memcg = MEMCGS[cgroup_id]
+    except KeyError:
+        err('Can\'t find the memory cgroup')
+
+    cfg = detect_kernel_config()
+
+    print('# name            <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>'
+          ' : tunables <limit> <batchcount> <sharedfactor>'
+          ' : slabdata <active_slabs> <num_slabs> <sharedavail>')
+
+    if cfg['shared_slab_pages']:
+        obj_cgroups = set()
+        stats = {}
+        caches = {}
+
+        # find memcg pointers belonging to the specified cgroup
+        obj_cgroups.add(memcg.objcg.value_())
+        for ptr in list_for_each_entry('struct obj_cgroup',
+                                       memcg.objcg_list.address_of_(),
+                                       'list'):
+            obj_cgroups.add(ptr.value_())
+
+        # look over all slab pages, belonging to non-root memcgs
+        # and look for objects belonging to the given memory cgroup
+        for page in for_each_slab_page(prog):
+            objcg_vec_raw = page.obj_cgroups.value_()
+            if objcg_vec_raw == 0:
+                continue
+            cache = page.slab_cache
+            if not cache:
+                continue
+            addr = cache.value_()
+            caches[addr] = cache
+            # clear the lowest bit to get the true obj_cgroups
+            objcg_vec = Object(prog, page.obj_cgroups.type_,
+                               value=objcg_vec_raw & ~1)
+
+            if addr not in stats:
+                stats[addr] = 0
+
+            for i in range(oo_objects(cache)):
+                if objcg_vec[i].value_() in obj_cgroups:
+                    stats[addr] += 1
+
+        for addr in caches:
+            if stats[addr] > 0:
+                cache_show(caches[addr], cfg, stats[addr])
+
+    else:
+        for s in list_for_each_entry('struct kmem_cache',
+                                     memcg.kmem_caches.address_of_(),
+                                     'memcg_params.kmem_caches_node'):
+            cache_show(s, cfg, None)
+
+
+main()
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

* Re: [PATCH v7 09/19] mm: memcg/slab: charge individual slab objects instead of pages
  2020-06-23  1:58 ` [PATCH v7 09/19] mm: memcg/slab: charge individual slab objects instead of pages Roman Gushchin
@ 2020-06-23  5:19   ` Shakeel Butt
  0 siblings, 0 replies; 25+ messages in thread
From: Shakeel Butt @ 2020-06-23  5:19 UTC (permalink / raw)
  To: Roman Gushchin
  Cc: Andrew Morton, Christoph Lameter, Johannes Weiner, Michal Hocko,
	Linux MM, Vlastimil Babka, Kernel Team, LKML

On Mon, Jun 22, 2020 at 6:58 PM Roman Gushchin <guro@fb.com> wrote:
>
> Switch to per-object accounting of non-root slab objects.
>
> Charging is performed using obj_cgroup API in the pre_alloc hook.
> Obj_cgroup is charged with the size of the object and the size of
> metadata: as now it's the size of an obj_cgroup pointer.  If the amount of
> memory has been charged successfully, the actual allocation code is
> executed.  Otherwise, -ENOMEM is returned.
>
> In the post_alloc hook if the actual allocation succeeded, corresponding
> vmstats are bumped and the obj_cgroup pointer is saved.  Otherwise, the
> charge is canceled.
>
> On the free path obj_cgroup pointer is obtained and used to uncharge the
> size of the releasing object.
>
> Memcg and lruvec counters are now representing only memory used by active
> slab objects and do not include the free space.  The free space is shared
> and doesn't belong to any specific cgroup.
>
> Global per-node slab vmstats are still modified from
> (un)charge_slab_page() functions.  The idea is to keep all slab pages
> accounted as slab pages on system level.
>
> Signed-off-by: Roman Gushchin <guro@fb.com>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> ---
[snip]
> +static inline struct kmem_cache *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
> +                                               struct obj_cgroup **objcgp,
> +                                               size_t objects, gfp_t flags)
> +{
> +       struct kmem_cache *cachep;
> +
> +       cachep = memcg_kmem_get_cache(s, objcgp);
> +       if (is_root_cache(cachep))
> +               return s;
> +
> +       if (obj_cgroup_charge(*objcgp, flags, objects * obj_full_size(s))) {
> +               memcg_kmem_put_cache(cachep);

I think you forgot to put obj_cgroup_put(*objcgp) here again.

> +               cachep = NULL;
> +       }
> +
> +       return cachep;
> +}
> +

After the above fix:

Reviewed-by: Shakeel Butt <shakeelb@google.com>


^ permalink raw reply	[flat|nested] 25+ messages in thread

* Re: [PATCH v7 17/19] mm: memcg/slab: use a single set of kmem_caches for all allocations
  2020-06-23  1:58 ` [PATCH v7 17/19] mm: memcg/slab: use a single set of kmem_caches for all allocations Roman Gushchin
@ 2020-06-23  5:25   ` Shakeel Butt
  0 siblings, 0 replies; 25+ messages in thread
From: Shakeel Butt @ 2020-06-23  5:25 UTC (permalink / raw)
  To: Roman Gushchin
  Cc: Andrew Morton, Christoph Lameter, Johannes Weiner, Michal Hocko,
	Linux MM, Vlastimil Babka, Kernel Team, LKML

On Mon, Jun 22, 2020 at 6:58 PM Roman Gushchin <guro@fb.com> wrote:
>
> Instead of having two sets of kmem_caches: one for system-wide and
> non-accounted allocations and the second one shared by all accounted
> allocations, we can use just one.
>
> The idea is simple: space for obj_cgroup metadata can be allocated on
> demand and filled only for accounted allocations.
>
> It allows to remove a bunch of code which is required to handle kmem_cache
> clones for accounted allocations.  There is no more need to create them,
> accumulate statistics, propagate attributes, etc.  It's a quite
> significant simplification.
>
> Also, because the total number of slab_caches is reduced almost twice (not
> all kmem_caches have a memcg clone), some additional memory savings are
> expected.  On my devvm it additionally saves about 3.5% of slab memory.
>
> Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
> Signed-off-by: Roman Gushchin <guro@fb.com>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>

Reviewed-by: Shakeel Butt <shakeelb@google.com>


^ permalink raw reply	[flat|nested] 25+ messages in thread

* Re: [PATCH v7 00/19] The new cgroup slab memory controller
  2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
                   ` (18 preceding siblings ...)
  2020-06-23  1:58 ` [PATCH v7 19/19] tools/cgroup: add memcg_slabinfo.py tool Roman Gushchin
@ 2020-06-23 13:53 ` Vlastimil Babka
  2020-06-23 15:39   ` Roman Gushchin
  19 siblings, 1 reply; 25+ messages in thread
From: Vlastimil Babka @ 2020-06-23 13:53 UTC (permalink / raw)
  To: Roman Gushchin, Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	kernel-team, linux-kernel, Jesper Dangaard Brouer

On 6/23/20 3:58 AM, Roman Gushchin wrote:
> This is v7 of the slab cgroup controller rework.

Hi,

As you and Jesper did those measurements on v6, and are sending v7, it would be
great to put some summary in the cover letter?

Thanks,
Vlastimil

> The patchset moves the accounting from the page level to the object
> level. It allows to share slab pages between memory cgroups.
> This leads to a significant win in the slab utilization (up to 45%)
> and the corresponding drop in the total kernel memory footprint.
> The reduced number of unmovable slab pages should also have a positive
> effect on the memory fragmentation.
> 
> The patchset makes the slab accounting code simpler: there is no more
> need in the complicated dynamic creation and destruction of per-cgroup
> slab caches, all memory cgroups use a global set of shared slab caches.
> The lifetime of slab caches is not more connected to the lifetime
> of memory cgroups.
> 
> The more precise accounting does require more CPU, however in practice
> the difference seems to be negligible. We've been using the new slab
> controller in Facebook production for several months with different
> workloads and haven't seen any noticeable regressions. What we've seen
> were memory savings in order of 1 GB per host (it varied heavily depending
> on the actual workload, size of RAM, number of CPUs, memory pressure, etc).
> 
> The third version of the patchset added yet another step towards
> the simplification of the code: sharing of slab caches between
> accounted and non-accounted allocations. It comes with significant
> upsides (most noticeable, a complete elimination of dynamic slab caches
> creation) but not without some regression risks, so this change sits
> on top of the patchset and is not completely merged in. So in the unlikely
> event of a noticeable performance regression it can be reverted separately.
> 
> The slab memory accounting works in exactly the same way for SLAB and SLUB.
> With both allocators the new controller shows significant memory savings,
> with SLUB the difference is bigger. On my 16-core desktop machine running
> Fedora 32 the size of the slab memory measured after the start of the system
> was lower by 58% and 38% with SLUB and SLAB correspondingly.
> 
> v7:
>   1) rebased on top of Vlastimil's slub improvements, by Andrew
>   2) page->obj_cgroups is allocated from the same node, by Shakeel
>   3) perf optimization in get_obj_cgroup_from_current(), by Shakeel
>   4) added synchronization around allocation of page->obj_cgroups,
>      by Shakeel
>   5) fixed kmemleak false positives, by Qian Cai
>   6) fixed a compiler warning on clang, by Nathan
>   7) other minor fixes
> 
> v6:
>   1) rebased on top of the mm tree
>   2) removed a redundant check from cache_from_obj(), suggested by Vlastimil
> 
> v5:
>   1) fixed a build error, spotted by Vlastimil
>   2) added a comment about memcg->nr_charged_bytes, asked by Johannes
>   3) added missed acks and reviews
> 
> v4:
>   1) rebased on top of the mm tree, some fixes here and there
>   2) merged obj_to_index() with slab_index(), suggested by Vlastimil
>   3) changed objects_per_slab() to a better objects_per_slab_page(),
>      suggested by Vlastimil
>   4) other minor fixes and changes
> 
> v3:
>   1) added a patch that switches to a global single set of kmem_caches
>   2) kmem API clean up dropped, because if has been already merged
>   3) byte-sized slab vmstat API over page-sized global counters and
>      bytes-sized memcg/lruvec counters
>   3) obj_cgroup refcounting simplifications and other minor fixes
>   4) other minor changes
> 
> v2:
>   1) implemented re-layering and renaming suggested by Johannes,
>      added his patch to the set. Thanks!
>   2) fixed the issue discovered by Bharata B Rao. Thanks!
>   3) added kmem API clean up part
>   4) added slab/memcg follow-up clean up part
>   5) fixed a couple of issues discovered by internal testing on FB fleet.
>   6) added kselftests
>   7) included metadata into the charge calculation
>   8) refreshed commit logs, regrouped patches, rebased onto mm tree, etc
> 
> v1:
>   1) fixed a bug in zoneinfo_show_print()
>   2) added some comments to the subpage charging API, a minor fix
>   3) separated memory.kmem.slabinfo deprecation into a separate patch,
>      provided a drgn-based replacement
>   4) rebased on top of the current mm tree
> 
> RFC:
>   https://lwn.net/Articles/798605/
> 
> 
> Johannes Weiner (1):
>   mm: memcontrol: decouple reference counting from page accounting
> 
> Roman Gushchin (18):
>   mm: memcg: factor out memcg- and lruvec-level changes out of
>     __mod_lruvec_state()
>   mm: memcg: prepare for byte-sized vmstat items
>   mm: memcg: convert vmstat slab counters to bytes
>   mm: slub: implement SLUB version of obj_to_index()
>   mm: memcg/slab: obj_cgroup API
>   mm: memcg/slab: allocate obj_cgroups for non-root slab pages
>   mm: memcg/slab: save obj_cgroup for non-root slab objects
>   mm: memcg/slab: charge individual slab objects instead of pages
>   mm: memcg/slab: deprecate memory.kmem.slabinfo
>   mm: memcg/slab: move memcg_kmem_bypass() to memcontrol.h
>   mm: memcg/slab: use a single set of kmem_caches for all accounted
>     allocations
>   mm: memcg/slab: simplify memcg cache creation
>   mm: memcg/slab: remove memcg_kmem_get_cache()
>   mm: memcg/slab: deprecate slab_root_caches
>   mm: memcg/slab: remove redundant check in memcg_accumulate_slabinfo()
>   mm: memcg/slab: use a single set of kmem_caches for all allocations
>   kselftests: cgroup: add kernel memory accounting tests
>   tools/cgroup: add memcg_slabinfo.py tool
> 
>  drivers/base/node.c                        |   6 +-
>  fs/proc/meminfo.c                          |   4 +-
>  include/linux/memcontrol.h                 |  85 ++-
>  include/linux/mm_types.h                   |   5 +-
>  include/linux/mmzone.h                     |  24 +-
>  include/linux/slab.h                       |   5 -
>  include/linux/slab_def.h                   |   9 +-
>  include/linux/slub_def.h                   |  31 +-
>  include/linux/vmstat.h                     |  14 +-
>  kernel/power/snapshot.c                    |   2 +-
>  mm/memcontrol.c                            | 610 +++++++++++--------
>  mm/oom_kill.c                              |   2 +-
>  mm/page_alloc.c                            |   8 +-
>  mm/slab.c                                  |  70 +--
>  mm/slab.h                                  | 370 +++++-------
>  mm/slab_common.c                           | 643 +--------------------
>  mm/slob.c                                  |  12 +-
>  mm/slub.c                                  | 229 +-------
>  mm/vmscan.c                                |   3 +-
>  mm/vmstat.c                                |  30 +-
>  mm/workingset.c                            |   6 +-
>  tools/cgroup/memcg_slabinfo.py             | 226 ++++++++
>  tools/testing/selftests/cgroup/.gitignore  |   1 +
>  tools/testing/selftests/cgroup/Makefile    |   2 +
>  tools/testing/selftests/cgroup/test_kmem.c | 382 ++++++++++++
>  25 files changed, 1380 insertions(+), 1399 deletions(-)
>  create mode 100644 tools/cgroup/memcg_slabinfo.py
>  create mode 100644 tools/testing/selftests/cgroup/test_kmem.c
> 



^ permalink raw reply	[flat|nested] 25+ messages in thread

* Re: [PATCH v7 00/19] The new cgroup slab memory controller
  2020-06-23 13:53 ` [PATCH v7 00/19] The new cgroup slab memory controller Vlastimil Babka
@ 2020-06-23 15:39   ` Roman Gushchin
  0 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23 15:39 UTC (permalink / raw)
  To: Vlastimil Babka
  Cc: Andrew Morton, Christoph Lameter, Johannes Weiner, Michal Hocko,
	Shakeel Butt, linux-mm, kernel-team, linux-kernel,
	Jesper Dangaard Brouer

On Tue, Jun 23, 2020 at 03:53:06PM +0200, Vlastimil Babka wrote:
> On 6/23/20 3:58 AM, Roman Gushchin wrote:
> > This is v7 of the slab cgroup controller rework.
> 
> Hi,
> 
> As you and Jesper did those measurements on v6, and are sending v7, it would be
> great to put some summary in the cover letter?

Good point! Let me add this and resend.

Thanks!


^ permalink raw reply	[flat|nested] 25+ messages in thread

* [PATCH v7 03/19] mm: memcg: convert vmstat slab counters to bytes
  2020-06-23 17:40 Roman Gushchin
@ 2020-06-23 17:40 ` Roman Gushchin
  0 siblings, 0 replies; 25+ messages in thread
From: Roman Gushchin @ 2020-06-23 17:40 UTC (permalink / raw)
  To: Andrew Morton, Christoph Lameter
  Cc: Johannes Weiner, Michal Hocko, Shakeel Butt, linux-mm,
	Vlastimil Babka, kernel-team, linux-kernel, Roman Gushchin

In order to prepare for per-object slab memory accounting, convert
NR_SLAB_RECLAIMABLE and NR_SLAB_UNRECLAIMABLE vmstat items to bytes.

To make it obvious, rename them to NR_SLAB_RECLAIMABLE_B and
NR_SLAB_UNRECLAIMABLE_B (similar to NR_KERNEL_STACK_KB).

Internally global and per-node counters are stored in pages, however memcg
and lruvec counters are stored in bytes.  This scheme may look weird, but
only for now.  As soon as slab pages will be shared between multiple
cgroups, global and node counters will reflect the total number of slab
pages.  However memcg and lruvec counters will be used for per-memcg slab
memory tracking, which will take separate kernel objects in the account.
Keeping global and node counters in pages helps to avoid additional
overhead.

The size of slab memory shouldn't exceed 4Gb on 32-bit machines, so it
will fit into atomic_long_t we use for vmstats.

Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 drivers/base/node.c     |  4 ++--
 fs/proc/meminfo.c       |  4 ++--
 include/linux/mmzone.h  | 16 +++++++++++++---
 kernel/power/snapshot.c |  2 +-
 mm/memcontrol.c         | 11 ++++-------
 mm/oom_kill.c           |  2 +-
 mm/page_alloc.c         |  8 ++++----
 mm/slab.h               | 15 ++++++++-------
 mm/slab_common.c        |  4 ++--
 mm/slob.c               | 12 ++++++------
 mm/slub.c               |  8 ++++----
 mm/vmscan.c             |  3 ++-
 mm/workingset.c         |  6 ++++--
 13 files changed, 53 insertions(+), 42 deletions(-)

diff --git a/drivers/base/node.c b/drivers/base/node.c
index e21e31359297..0cf13e31603c 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -368,8 +368,8 @@ static ssize_t node_read_meminfo(struct device *dev,
 	unsigned long sreclaimable, sunreclaimable;
 
 	si_meminfo_node(&i, nid);
-	sreclaimable = node_page_state(pgdat, NR_SLAB_RECLAIMABLE);
-	sunreclaimable = node_page_state(pgdat, NR_SLAB_UNRECLAIMABLE);
+	sreclaimable = node_page_state_pages(pgdat, NR_SLAB_RECLAIMABLE_B);
+	sunreclaimable = node_page_state_pages(pgdat, NR_SLAB_UNRECLAIMABLE_B);
 	n = sprintf(buf,
 		       "Node %d MemTotal:       %8lu kB\n"
 		       "Node %d MemFree:        %8lu kB\n"
diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
index e9a6841fc25b..38ea95fd919a 100644
--- a/fs/proc/meminfo.c
+++ b/fs/proc/meminfo.c
@@ -52,8 +52,8 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
 		pages[lru] = global_node_page_state(NR_LRU_BASE + lru);
 
 	available = si_mem_available();
-	sreclaimable = global_node_page_state(NR_SLAB_RECLAIMABLE);
-	sunreclaim = global_node_page_state(NR_SLAB_UNRECLAIMABLE);
+	sreclaimable = global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B);
+	sunreclaim = global_node_page_state_pages(NR_SLAB_UNRECLAIMABLE_B);
 
 	show_val_kb(m, "MemTotal:       ", i.totalram);
 	show_val_kb(m, "MemFree:        ", i.freeram);
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index f16306e15b98..b79100edd228 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -174,8 +174,8 @@ enum node_stat_item {
 	NR_INACTIVE_FILE,	/*  "     "     "   "       "         */
 	NR_ACTIVE_FILE,		/*  "     "     "   "       "         */
 	NR_UNEVICTABLE,		/*  "     "     "   "       "         */
-	NR_SLAB_RECLAIMABLE,
-	NR_SLAB_UNRECLAIMABLE,
+	NR_SLAB_RECLAIMABLE_B,
+	NR_SLAB_UNRECLAIMABLE_B,
 	NR_ISOLATED_ANON,	/* Temporary isolated pages from anon lru */
 	NR_ISOLATED_FILE,	/* Temporary isolated pages from file lru */
 	WORKINGSET_NODES,
@@ -213,7 +213,17 @@ enum node_stat_item {
  */
 static __always_inline bool vmstat_item_in_bytes(int idx)
 {
-	return false;
+	/*
+	 * Global and per-node slab counters track slab pages.
+	 * It's expected that changes are multiples of PAGE_SIZE.
+	 * Internally values are stored in pages.
+	 *
+	 * Per-memcg and per-lruvec counters track memory, consumed
+	 * by individual slab objects. These counters are actually
+	 * byte-precise.
+	 */
+	return (idx == NR_SLAB_RECLAIMABLE_B ||
+		idx == NR_SLAB_UNRECLAIMABLE_B);
 }
 
 /*
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 881128b9351e..eefc907e5324 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -1663,7 +1663,7 @@ static unsigned long minimum_image_size(unsigned long saveable)
 {
 	unsigned long size;
 
-	size = global_node_page_state(NR_SLAB_RECLAIMABLE)
+	size = global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B)
 		+ global_node_page_state(NR_ACTIVE_ANON)
 		+ global_node_page_state(NR_INACTIVE_ANON)
 		+ global_node_page_state(NR_ACTIVE_FILE)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 246f9c70118c..a6216f7369b2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1391,9 +1391,8 @@ static char *memory_stat_format(struct mem_cgroup *memcg)
 		       (u64)memcg_page_state(memcg, MEMCG_KERNEL_STACK_KB) *
 		       1024);
 	seq_buf_printf(&s, "slab %llu\n",
-		       (u64)(memcg_page_state(memcg, NR_SLAB_RECLAIMABLE) +
-			     memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE)) *
-		       PAGE_SIZE);
+		       (u64)(memcg_page_state(memcg, NR_SLAB_RECLAIMABLE_B) +
+			     memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE_B)));
 	seq_buf_printf(&s, "sock %llu\n",
 		       (u64)memcg_page_state(memcg, MEMCG_SOCK) *
 		       PAGE_SIZE);
@@ -1423,11 +1422,9 @@ static char *memory_stat_format(struct mem_cgroup *memcg)
 			       PAGE_SIZE);
 
 	seq_buf_printf(&s, "slab_reclaimable %llu\n",
-		       (u64)memcg_page_state(memcg, NR_SLAB_RECLAIMABLE) *
-		       PAGE_SIZE);
+		       (u64)memcg_page_state(memcg, NR_SLAB_RECLAIMABLE_B));
 	seq_buf_printf(&s, "slab_unreclaimable %llu\n",
-		       (u64)memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE) *
-		       PAGE_SIZE);
+		       (u64)memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE_B));
 
 	/* Accumulated memory events */
 
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 6e94962893ee..d30ce75f23fb 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -184,7 +184,7 @@ static bool is_dump_unreclaim_slabs(void)
 		 global_node_page_state(NR_ISOLATED_FILE) +
 		 global_node_page_state(NR_UNEVICTABLE);
 
-	return (global_node_page_state(NR_SLAB_UNRECLAIMABLE) > nr_lru);
+	return (global_node_page_state_pages(NR_SLAB_UNRECLAIMABLE_B) > nr_lru);
 }
 
 /**
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 48eb0f1410d4..2304929c6a84 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5220,8 +5220,8 @@ long si_mem_available(void)
 	 * items that are in use, and cannot be freed. Cap this estimate at the
 	 * low watermark.
 	 */
-	reclaimable = global_node_page_state(NR_SLAB_RECLAIMABLE) +
-			global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE);
+	reclaimable = global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B) +
+		global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE);
 	available += reclaimable - min(reclaimable / 2, wmark_low);
 
 	if (available < 0)
@@ -5364,8 +5364,8 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
 		global_node_page_state(NR_UNEVICTABLE),
 		global_node_page_state(NR_FILE_DIRTY),
 		global_node_page_state(NR_WRITEBACK),
-		global_node_page_state(NR_SLAB_RECLAIMABLE),
-		global_node_page_state(NR_SLAB_UNRECLAIMABLE),
+		global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B),
+		global_node_page_state_pages(NR_SLAB_UNRECLAIMABLE_B),
 		global_node_page_state(NR_FILE_MAPPED),
 		global_node_page_state(NR_SHMEM),
 		global_zone_page_state(NR_PAGETABLE),
diff --git a/mm/slab.h b/mm/slab.h
index 136dead286b0..cc6afddd5632 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -272,7 +272,7 @@ int __kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
 static inline int cache_vmstat_idx(struct kmem_cache *s)
 {
 	return (s->flags & SLAB_RECLAIM_ACCOUNT) ?
-		NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE;
+		NR_SLAB_RECLAIMABLE_B : NR_SLAB_UNRECLAIMABLE_B;
 }
 
 #ifdef CONFIG_SLUB_DEBUG
@@ -389,7 +389,7 @@ static __always_inline int memcg_charge_slab(struct page *page,
 
 	if (unlikely(!memcg || mem_cgroup_is_root(memcg))) {
 		mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
-				    nr_pages);
+				    nr_pages << PAGE_SHIFT);
 		percpu_ref_get_many(&s->memcg_params.refcnt, nr_pages);
 		return 0;
 	}
@@ -399,7 +399,7 @@ static __always_inline int memcg_charge_slab(struct page *page,
 		goto out;
 
 	lruvec = mem_cgroup_lruvec(memcg, page_pgdat(page));
-	mod_lruvec_state(lruvec, cache_vmstat_idx(s), nr_pages);
+	mod_lruvec_state(lruvec, cache_vmstat_idx(s), nr_pages << PAGE_SHIFT);
 
 	/* transer try_charge() page references to kmem_cache */
 	percpu_ref_get_many(&s->memcg_params.refcnt, nr_pages);
@@ -424,11 +424,12 @@ static __always_inline void memcg_uncharge_slab(struct page *page, int order,
 	memcg = READ_ONCE(s->memcg_params.memcg);
 	if (likely(!mem_cgroup_is_root(memcg))) {
 		lruvec = mem_cgroup_lruvec(memcg, page_pgdat(page));
-		mod_lruvec_state(lruvec, cache_vmstat_idx(s), -nr_pages);
+		mod_lruvec_state(lruvec, cache_vmstat_idx(s),
+				 -(nr_pages << PAGE_SHIFT));
 		memcg_kmem_uncharge(memcg, nr_pages);
 	} else {
 		mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
-				    -nr_pages);
+				    -(nr_pages << PAGE_SHIFT));
 	}
 	rcu_read_unlock();
 
@@ -512,7 +513,7 @@ static __always_inline int charge_slab_page(struct page *page,
 {
 	if (is_root_cache(s)) {
 		mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
-				    1 << order);
+				    PAGE_SIZE << order);
 		return 0;
 	}
 
@@ -524,7 +525,7 @@ static __always_inline void uncharge_slab_page(struct page *page, int order,
 {
 	if (is_root_cache(s)) {
 		mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
-				    -(1 << order));
+				    -(PAGE_SIZE << order));
 		return;
 	}
 
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 5c2c11e59f0a..4fb76b45ce23 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1325,8 +1325,8 @@ void *kmalloc_order(size_t size, gfp_t flags, unsigned int order)
 	page = alloc_pages(flags, order);
 	if (likely(page)) {
 		ret = page_address(page);
-		mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE,
-				    1 << order);
+		mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE_B,
+				    PAGE_SIZE << order);
 	}
 	ret = kasan_kmalloc_large(ret, size, flags);
 	/* As ret might get tagged, call kmemleak hook after KASAN. */
diff --git a/mm/slob.c b/mm/slob.c
index ac2aecfbc7a8..7cc9805c8091 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -202,8 +202,8 @@ static void *slob_new_pages(gfp_t gfp, int order, int node)
 	if (!page)
 		return NULL;
 
-	mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE,
-			    1 << order);
+	mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE_B,
+			    PAGE_SIZE << order);
 	return page_address(page);
 }
 
@@ -214,8 +214,8 @@ static void slob_free_pages(void *b, int order)
 	if (current->reclaim_state)
 		current->reclaim_state->reclaimed_slab += 1 << order;
 
-	mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE,
-			    -(1 << order));
+	mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE_B,
+			    -(PAGE_SIZE << order));
 	__free_pages(sp, order);
 }
 
@@ -552,8 +552,8 @@ void kfree(const void *block)
 		slob_free(m, *m + align);
 	} else {
 		unsigned int order = compound_order(sp);
-		mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE,
-				    -(1 << order));
+		mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE_B,
+				    -(PAGE_SIZE << order));
 		__free_pages(sp, order);
 
 	}
diff --git a/mm/slub.c b/mm/slub.c
index 767738306171..c79d33cbe815 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3995,8 +3995,8 @@ static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
 	page = alloc_pages_node(node, flags, order);
 	if (page) {
 		ptr = page_address(page);
-		mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE,
-				    1 << order);
+		mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE_B,
+				    PAGE_SIZE << order);
 	}
 
 	return kmalloc_large_node_hook(ptr, size, flags);
@@ -4127,8 +4127,8 @@ void kfree(const void *x)
 
 		BUG_ON(!PageCompound(page));
 		kfree_hook(object);
-		mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE,
-				    -(1 << order));
+		mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE_B,
+				    -(PAGE_SIZE << order));
 		__free_pages(page, order);
 		return;
 	}
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 749d239c62b2..2ac43664aba4 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4222,7 +4222,8 @@ int node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned int order)
 	 * unmapped file backed pages.
 	 */
 	if (node_pagecache_reclaimable(pgdat) <= pgdat->min_unmapped_pages &&
-	    node_page_state(pgdat, NR_SLAB_RECLAIMABLE) <= pgdat->min_slab_pages)
+	    node_page_state_pages(pgdat, NR_SLAB_RECLAIMABLE_B) <=
+	    pgdat->min_slab_pages)
 		return NODE_RECLAIM_FULL;
 
 	/*
diff --git a/mm/workingset.c b/mm/workingset.c
index 50b7937bab32..b199726924dd 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -486,8 +486,10 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker,
 		for (pages = 0, i = 0; i < NR_LRU_LISTS; i++)
 			pages += lruvec_page_state_local(lruvec,
 							 NR_LRU_BASE + i);
-		pages += lruvec_page_state_local(lruvec, NR_SLAB_RECLAIMABLE);
-		pages += lruvec_page_state_local(lruvec, NR_SLAB_UNRECLAIMABLE);
+		pages += lruvec_page_state_local(
+			lruvec, NR_SLAB_RECLAIMABLE_B) >> PAGE_SHIFT;
+		pages += lruvec_page_state_local(
+			lruvec, NR_SLAB_UNRECLAIMABLE_B) >> PAGE_SHIFT;
 	} else
 #endif
 		pages = node_present_pages(sc->nid);
-- 
2.26.2



^ permalink raw reply related	[flat|nested] 25+ messages in thread

end of thread, other threads:[~2020-06-23 17:40 UTC | newest]

Thread overview: 25+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 01/19] mm: memcg: factor out memcg- and lruvec-level changes out of __mod_lruvec_state() Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 02/19] mm: memcg: prepare for byte-sized vmstat items Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 03/19] mm: memcg: convert vmstat slab counters to bytes Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 04/19] mm: slub: implement SLUB version of obj_to_index() Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 05/19] mm: memcontrol: decouple reference counting from page accounting Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 06/19] mm: memcg/slab: obj_cgroup API Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 07/19] mm: memcg/slab: allocate obj_cgroups for non-root slab pages Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 08/19] mm: memcg/slab: save obj_cgroup for non-root slab objects Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 09/19] mm: memcg/slab: charge individual slab objects instead of pages Roman Gushchin
2020-06-23  5:19   ` Shakeel Butt
2020-06-23  1:58 ` [PATCH v7 10/19] mm: memcg/slab: deprecate memory.kmem.slabinfo Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 11/19] mm: memcg/slab: move memcg_kmem_bypass() to memcontrol.h Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 12/19] mm: memcg/slab: use a single set of kmem_caches for all accounted allocations Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 13/19] mm: memcg/slab: simplify memcg cache creation Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 14/19] mm: memcg/slab: remove memcg_kmem_get_cache() Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 15/19] mm: memcg/slab: deprecate slab_root_caches Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 16/19] mm: memcg/slab: remove redundant check in memcg_accumulate_slabinfo() Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 17/19] mm: memcg/slab: use a single set of kmem_caches for all allocations Roman Gushchin
2020-06-23  5:25   ` Shakeel Butt
2020-06-23  1:58 ` [PATCH v7 18/19] kselftests: cgroup: add kernel memory accounting tests Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 19/19] tools/cgroup: add memcg_slabinfo.py tool Roman Gushchin
2020-06-23 13:53 ` [PATCH v7 00/19] The new cgroup slab memory controller Vlastimil Babka
2020-06-23 15:39   ` Roman Gushchin
2020-06-23 17:40 Roman Gushchin
2020-06-23 17:40 ` [PATCH v7 03/19] mm: memcg: convert vmstat slab counters to bytes Roman Gushchin

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).