From: Roman Gushchin <guro@fb.com>
To: Andrew Morton <akpm@linux-foundation.org>, <linux-mm@kvack.org>
Cc: Shakeel Butt <shakeelb@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>, <linux-kernel@vger.kernel.org>,
<kernel-team@fb.com>, Roman Gushchin <guro@fb.com>,
<stable@vger.kernel.org>
Subject: [PATCH] mm: memcg/slab: fix obj_cgroup_charge() return value handling
Date: Thu, 26 Nov 2020 20:14:05 -0800 [thread overview]
Message-ID: <20201127041405.3459198-1-guro@fb.com> (raw)
Commit 10befea91b61 ("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: 10befea91b61 ("mm: memcg/slab: use a single set of kmem_caches for all allocations")
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: stable@vger.kernel.org
---
mm/slab.h | 40 ++++++++++++++++++++++++----------------
1 file changed, 24 insertions(+), 16 deletions(-)
diff --git a/mm/slab.h b/mm/slab.h
index 59aeb0d9f11b..5dc89d8fb05e 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -257,22 +257,32 @@ 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 true 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 false;
+
+ if (!(flags & __GFP_ACCOUNT) && !(s->flags & SLAB_ACCOUNT))
+ return false;
+
objcg = get_obj_cgroup_from_current();
if (!objcg)
- return NULL;
+ return false;
if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s))) {
obj_cgroup_put(objcg);
- return NULL;
+ return true;
}
- return objcg;
+ *objcgp = objcg;
+ return false;
}
static inline void mod_objcg_state(struct obj_cgroup *objcg,
@@ -298,7 +308,7 @@ 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;
@@ -382,11 +392,11 @@ 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 false;
}
static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
@@ -494,9 +504,8 @@ 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;
}
@@ -515,8 +524,7 @@ 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
--
2.26.2
next reply other threads:[~2020-11-27 4:14 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-27 4:14 Roman Gushchin [this message]
2020-11-27 5:55 ` [PATCH] mm: memcg/slab: fix obj_cgroup_charge() return value handling Shakeel Butt
2020-11-27 16:18 ` Roman Gushchin
2020-11-28 4:42 ` Shakeel Butt
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