[Devel] [PATCH 06/10] sl[au]b: Allocate objects from memcg cache

[Glauber Costa]

We are able to match a cache allocation to a particular memcg.  If the
task doesn't change groups during the allocation itself - a rare event,
this will give us a good picture about who is the first group to touch a
cache page.

This patch uses the now available infrastructure by calling
memcg_kmem_get_cache() before all the cache allocations.

Signed-off-by: Glauber Costa <glommer at parallels.com>
CC: Christoph Lameter <cl at linux.com>
CC: Pekka Enberg <penberg at cs.helsinki.fi>
CC: Michal Hocko <mhocko at suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
CC: Johannes Weiner <hannes at cmpxchg.org>
CC: Suleiman Souhlal <suleiman at google.com>
---
 include/linux/slub_def.h |   18 +++++++++++++-----
 mm/memcontrol.c          |    2 ++
 mm/slab.c                |    4 ++++
 mm/slub.c                |    1 +
 4 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 8bb8ad2..148000a 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -13,6 +13,8 @@
 #include <linux/kobject.h>
 
 #include <linux/kmemleak.h>
+#include <linux/memcontrol.h>
+#include <linux/mm.h>
 
 enum stat_item {
 	ALLOC_FASTPATH,		/* Allocation from cpu slab */
@@ -209,14 +211,14 @@ static __always_inline int kmalloc_index(size_t size)
  * This ought to end up with a global pointer to the right cache
  * in kmalloc_caches.
  */
-static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
+static __always_inline struct kmem_cache *kmalloc_slab(gfp_t flags, size_t size)
 {
 	int index = kmalloc_index(size);
 
 	if (index == 0)
 		return NULL;
 
-	return kmalloc_caches[index];
+	return memcg_kmem_get_cache(kmalloc_caches[index], flags);
 }
 
 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
@@ -225,7 +227,13 @@ void *__kmalloc(size_t size, gfp_t flags);
 static __always_inline void *
 kmalloc_order(size_t size, gfp_t flags, unsigned int order)
 {
-	void *ret = (void *) __get_free_pages(flags | __GFP_COMP, order);
+	void *ret;
+
+	flags = __GFP_COMP;
+#ifdef CONFIG_MEMCG_KMEM
+	flags |= __GFP_KMEMCG;
+#endif
+	ret = (void *) __get_free_pages(flags, order);
 	kmemleak_alloc(ret, size, 1, flags);
 	return ret;
 }
@@ -274,7 +282,7 @@ static __always_inline void *kmalloc(size_t size, gfp_t flags)
 			return kmalloc_large(size, flags);
 
 		if (!(flags & SLUB_DMA)) {
-			struct kmem_cache *s = kmalloc_slab(size);
+			struct kmem_cache *s = kmalloc_slab(flags, size);
 
 			if (!s)
 				return ZERO_SIZE_PTR;
@@ -307,7 +315,7 @@ static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 {
 	if (__builtin_constant_p(size) &&
 		size <= SLUB_MAX_SIZE && !(flags & SLUB_DMA)) {
-			struct kmem_cache *s = kmalloc_slab(size);
+			struct kmem_cache *s = kmalloc_slab(flags, size);
 
 		if (!s)
 			return ZERO_SIZE_PTR;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index b933474..2cc3acf 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -586,6 +586,8 @@ static struct kmem_cache *kmem_cache_dup(struct mem_cgroup *memcg,
 
 	new = kmem_cache_create_memcg(memcg, name, s->object_size, s->align,
 				      (s->flags & ~SLAB_PANIC), s->ctor, s);
+	if (new)
+		new->allocflags |= __GFP_KMEMCG;
 
 	kfree(name);
 	return new;
diff --git a/mm/slab.c b/mm/slab.c
index 76bc98f..ddc60a4 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3316,6 +3316,8 @@ __cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
 	if (slab_should_failslab(cachep, flags))
 		return NULL;
 
+	cachep = memcg_kmem_get_cache(cachep, flags);
+
 	cache_alloc_debugcheck_before(cachep, flags);
 	local_irq_save(save_flags);
 
@@ -3401,6 +3403,8 @@ __cache_alloc(struct kmem_cache *cachep, gfp_t flags, void *caller)
 	if (slab_should_failslab(cachep, flags))
 		return NULL;
 
+	cachep = memcg_kmem_get_cache(cachep, flags);
+
 	cache_alloc_debugcheck_before(cachep, flags);
 	local_irq_save(save_flags);
 	objp = __do_cache_alloc(cachep, flags);
diff --git a/mm/slub.c b/mm/slub.c
index 417a806..6175a72 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2292,6 +2292,7 @@ static __always_inline void *slab_alloc(struct kmem_cache *s,
 	if (slab_pre_alloc_hook(s, gfpflags))
 		return NULL;
 
+	s = memcg_kmem_get_cache(s, gfpflags);
 redo:
 
 	/*
-- 
1.7.10.4