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mm: memcg/slab: fix obj_cgroup_charge() return value handling 

Commit 10befea91b ("mm: memcg/slab: use a single set of kmem_caches
for all allocations") introduced a regression into the handling of the
obj_cgroup_charge() return value.  If a non-zero value is returned
(indicating of exceeding one of memory.max limits), the allocation
should fail, instead of falling back to non-accounted mode.

To make the code more readable, move memcg_slab_pre_alloc_hook() and
memcg_slab_post_alloc_hook() calling conditions into bodies of these
hooks.

Fixes: 10befea91b ("mm: memcg/slab: use a single set of kmem_caches for all allocations")
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20201127161828.GD840171@carbon.dhcp.thefacebook.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
zero-sugar-mainline-defconfig
Roman Gushchin 2020-12-05 22:14:45 -08:00 committed by Linus Torvalds
parent 2bf509d96d
commit becaba65f6
1 changed files with 24 additions and 16 deletions
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40
mm/slab.h
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@ -274,22 +274,32 @@ static inline size_t obj_full_size(struct kmem_cache *s)
return s->size + sizeof(struct obj_cgroup *);
}
static inline struct obj_cgroup *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
size_t objects,
gfp_t flags)
/*
* Returns false if the allocation should fail.
*/
static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s,
struct obj_cgroup **objcgp,
size_t objects, gfp_t flags)
{
struct obj_cgroup *objcg;
if (!memcg_kmem_enabled())
return true;
if (!(flags & __GFP_ACCOUNT) && !(s->flags & SLAB_ACCOUNT))
return true;
objcg = get_obj_cgroup_from_current();
if (!objcg)
return NULL;
return true;
if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s))) {
obj_cgroup_put(objcg);
return NULL;
return false;
}
return objcg;
*objcgp = objcg;
return true;
}
static inline void mod_objcg_state(struct obj_cgroup *objcg,
@ -315,7 +325,7 @@ static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
unsigned long off;
size_t i;
if (!objcg)
if (!memcg_kmem_enabled() || !objcg)
return;
flags &= ~__GFP_ACCOUNT;
@ -400,11 +410,11 @@ static inline void memcg_free_page_obj_cgroups(struct page *page)
{
}
static inline struct obj_cgroup *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
size_t objects,
gfp_t flags)
static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s,
struct obj_cgroup **objcgp,
size_t objects, gfp_t flags)
{
return NULL;
return true;
}
static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
@ -508,9 +518,8 @@ static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
if (should_failslab(s, flags))
return NULL;
if (memcg_kmem_enabled() &&
((flags & __GFP_ACCOUNT) || (s->flags & SLAB_ACCOUNT)))
*objcgp = memcg_slab_pre_alloc_hook(s, size, flags);
if (!memcg_slab_pre_alloc_hook(s, objcgp, size, flags))
return NULL;
return s;
}
@ -529,8 +538,7 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s,
s->flags, flags);
}
if (memcg_kmem_enabled())
memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
}
#ifndef CONFIG_SLOB