Re: [PATCH 11/23] slub: consider a memcg parameter in kmem_create_cache
From: Glauber Costa
Date: Wed May 02 2012 - 11:20:17 EST
On 04/30/2012 04:51 PM, Suleiman Souhlal wrote:
On Fri, Apr 20, 2012 at 2:57 PM, Glauber Costa<glommer@xxxxxxxxxxxxx> wrote:
Allow a memcg parameter to be passed during cache creation.
The slub allocator will only merge caches that belong to
the same memcg.
Default function is created as a wrapper, passing NULL
to the memcg version. We only merge caches that belong
to the same memcg.
From the memcontrol.c side, 3 helper functions are created:
1) memcg_css_id: because slub needs a unique cache name
for sysfs. Since this is visible, but not the canonical
location for slab data, the cache name is not used, the
css_id should suffice.
2) mem_cgroup_register_cache: is responsible for assigning
a unique index to each cache, and other general purpose
setup. The index is only assigned for the root caches. All
others are assigned index == -1.
3) mem_cgroup_release_cache: can be called from the root cache
destruction, and will release the index for other caches.
This index mechanism was developed by Suleiman Souhlal.
Signed-off-by: Glauber Costa<glommer@xxxxxxxxxxxxx>
CC: Christoph Lameter<cl@xxxxxxxxx>
CC: Pekka Enberg<penberg@xxxxxxxxxxxxxx>
CC: Michal Hocko<mhocko@xxxxxxx>
CC: Kamezawa Hiroyuki<kamezawa.hiroyu@xxxxxxxxxxxxxx>
CC: Johannes Weiner<hannes@xxxxxxxxxxx>
CC: Suleiman Souhlal<suleiman@xxxxxxxxxx>
---
include/linux/memcontrol.h | 14 ++++++++++++++
include/linux/slab.h | 6 ++++++
mm/memcontrol.c | 29 +++++++++++++++++++++++++++++
mm/slub.c | 31 +++++++++++++++++++++++++++----
4 files changed, 76 insertions(+), 4 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index f94efd2..99e14b9 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -26,6 +26,7 @@ struct mem_cgroup;
struct page_cgroup;
struct page;
struct mm_struct;
+struct kmem_cache;
/* Stats that can be updated by kernel. */
enum mem_cgroup_page_stat_item {
@@ -440,7 +441,20 @@ struct sock;
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
void sock_update_memcg(struct sock *sk);
void sock_release_memcg(struct sock *sk);
+int memcg_css_id(struct mem_cgroup *memcg);
+void mem_cgroup_register_cache(struct mem_cgroup *memcg,
+ struct kmem_cache *s);
+void mem_cgroup_release_cache(struct kmem_cache *cachep);
#else
+static inline void mem_cgroup_register_cache(struct mem_cgroup *memcg,
+ struct kmem_cache *s)
+{
+}
+
+static inline void mem_cgroup_release_cache(struct kmem_cache *cachep)
+{
+}
+
static inline void sock_update_memcg(struct sock *sk)
{
}
diff --git a/include/linux/slab.h b/include/linux/slab.h
index a5127e1..c7a7e05 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -321,6 +321,12 @@ extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
__kmalloc(size, flags)
#endif /* DEBUG_SLAB */
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+#define MAX_KMEM_CACHE_TYPES 400
+#else
+#define MAX_KMEM_CACHE_TYPES 0
+#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
+
#ifdef CONFIG_NUMA
/*
* kmalloc_node_track_caller is a special version of kmalloc_node that
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 36f1e6b..0015ed0 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -323,6 +323,11 @@ struct mem_cgroup {
#endif
};
+int memcg_css_id(struct mem_cgroup *memcg)
+{
+ return css_id(&memcg->css);
+}
+
/* Stuffs for move charges at task migration. */
/*
* Types of charges to be moved. "move_charge_at_immitgrate" is treated as a
@@ -461,6 +466,30 @@ struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
}
EXPORT_SYMBOL(tcp_proto_cgroup);
#endif /* CONFIG_INET */
+
+/* Bitmap used for allocating the cache id numbers. */
+static DECLARE_BITMAP(cache_types, MAX_KMEM_CACHE_TYPES);
+
+void mem_cgroup_register_cache(struct mem_cgroup *memcg,
+ struct kmem_cache *cachep)
+{
+ int id = -1;
+
+ cachep->memcg_params.memcg = memcg;
+
+ if (!memcg) {
+ id = find_first_zero_bit(cache_types, MAX_KMEM_CACHE_TYPES);
+ BUG_ON(id< 0 || id>= MAX_KMEM_CACHE_TYPES);
+ __set_bit(id, cache_types);
+ } else
+ INIT_LIST_HEAD(&cachep->memcg_params.destroyed_list);
+ cachep->memcg_params.id = id;
+}
+
+void mem_cgroup_release_cache(struct kmem_cache *cachep)
+{
+ __clear_bit(cachep->memcg_params.id, cache_types);
+}
#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
static void drain_all_stock_async(struct mem_cgroup *memcg);
diff --git a/mm/slub.c b/mm/slub.c
index 2652e7c..86e40cc 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -32,6 +32,7 @@
#include<linux/prefetch.h>
#include<trace/events/kmem.h>
+#include<linux/memcontrol.h>
/*
* Lock order:
@@ -3880,7 +3881,7 @@ static int slab_unmergeable(struct kmem_cache *s)
return 0;
}
-static struct kmem_cache *find_mergeable(size_t size,
+static struct kmem_cache *find_mergeable(struct mem_cgroup *memcg, size_t size,
size_t align, unsigned long flags, const char *name,
void (*ctor)(void *))
{
@@ -3916,21 +3917,29 @@ static struct kmem_cache *find_mergeable(size_t size,
if (s->size - size>= sizeof(void *))
continue;
+ if (memcg&& s->memcg_params.memcg != memcg)
+ continue;
+
return s;
}
return NULL;
}
-struct kmem_cache *kmem_cache_create(const char *name, size_t size,
- size_t align, unsigned long flags, void (*ctor)(void *))
+struct kmem_cache *
+kmem_cache_create_memcg(struct mem_cgroup *memcg, const char *name, size_t size,
+ size_t align, unsigned long flags, void (*ctor)(void *))
{
struct kmem_cache *s;
if (WARN_ON(!name))
return NULL;
+#ifndef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ WARN_ON(memcg != NULL);
+#endif
+
down_write(&slub_lock);
- s = find_mergeable(size, align, flags, name, ctor);
+ s = find_mergeable(memcg, size, align, flags, name, ctor);
if (s) {
s->refcount++;
/*
@@ -3954,12 +3963,15 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
size, align, flags, ctor)) {
list_add(&s->list,&slab_caches);
up_write(&slub_lock);
+ mem_cgroup_register_cache(memcg, s);
Do the kmalloc caches get their id registered correctly?
For the slub, it seems to work okay. But I had to use the trick that for
the memcg-specific kmalloc caches, they come from the normal caches
rather than the special kmalloc pool. Since we are already paying the
penalty of dealing with the memcg finding, I hope this is okay.
For the slab, my investigation wasn't that deep. But basic functionality
works okay.
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