linux-mm.kvack.org archive mirror
 help / color / mirror / Atom feed
From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, guro@fb.com, hannes@cmpxchg.org,
	linux-mm@kvack.org, mhocko@kernel.org,
	mm-commits@vger.kernel.org, shakeelb@google.com,
	stable@vger.kernel.org, torvalds@linux-foundation.org
Subject: [patch 03/12] mm: memcg/slab: fix obj_cgroup_charge() return value handling
Date: Sat, 05 Dec 2020 22:14:45 -0800	[thread overview]
Message-ID: <20201206061445.FBPPaghTp%akpm@linux-foundation.org> (raw)
In-Reply-To: <20201205221412.67f14b9b3a5ef531c76dd452@linux-foundation.org>

From: Roman Gushchin <guro@fb.com>
Subject: mm: memcg/slab: fix obj_cgroup_charge() return value handling

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.

Link: https://lkml.kernel.org/r/20201127161828.GD840171@carbon.dhcp.thefacebook.com
Fixes: 10befea91b61 ("mm: memcg/slab: use a single set of kmem_caches for all allocations")
Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/slab.h |   40 ++++++++++++++++++++++++----------------
 1 file changed, 24 insertions(+), 16 deletions(-)

--- a/mm/slab.h~mm-memcg-slab-fix-obj_cgroup_charge-return-value-handling
+++ a/mm/slab.h
@@ -274,22 +274,32 @@ static inline size_t obj_full_size(struc
 	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
 	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_c
 {
 }
 
-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_pr
 	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(
 					 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
_


  parent reply	other threads:[~2020-12-06  6:14 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-06  6:14 incoming Andrew Morton
2020-12-06  6:14 ` [patch 01/12] zlib: export S390 symbols for zlib modules Andrew Morton
2020-12-07  9:03   ` Zaslonko Mikhail
2020-12-08  0:45     ` Randy Dunlap
2020-12-08  8:19       ` Zaslonko Mikhail
2020-12-18 22:18         ` Randy Dunlap
2020-12-06  6:14 ` [patch 02/12] coredump: fix core_pattern parse error Andrew Morton
2020-12-06  6:14 ` Andrew Morton [this message]
2020-12-06  6:14 ` [patch 04/12] mm: list_lru: set shrinker map bit when child nr_items is not zero Andrew Morton
2020-12-06  6:14 ` [patch 05/12] mm/zsmalloc.c: drop ZSMALLOC_PGTABLE_MAPPING Andrew Morton
2020-12-06  6:14 ` [patch 06/12] mm/swapfile: do not sleep with a spin lock held Andrew Morton
2020-12-06  6:14 ` [patch 07/12] mailmap: add two more addresses of Uwe Kleine-König Andrew Morton
2020-12-06  6:15 ` [patch 08/12] tools/testing/selftests/vm: fix build error Andrew Morton
2020-12-06  6:15 ` [patch 09/12] userfaultfd: selftests: fix SIGSEGV if huge mmap fails Andrew Morton
2020-12-06  6:15 ` [patch 10/12] mm/filemap: add static for function __add_to_page_cache_locked Andrew Morton
2020-12-06  6:15 ` [patch 11/12] hugetlb_cgroup: fix offline of hugetlb cgroup with reservations Andrew Morton
2020-12-06  6:15 ` [patch 12/12] mm/mmap.c: fix mmap return value when vma is merged after call_mmap() Andrew Morton

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201206061445.FBPPaghTp%akpm@linux-foundation.org \
    --to=akpm@linux-foundation.org \
    --cc=guro@fb.com \
    --cc=hannes@cmpxchg.org \
    --cc=linux-mm@kvack.org \
    --cc=mhocko@kernel.org \
    --cc=mm-commits@vger.kernel.org \
    --cc=shakeelb@google.com \
    --cc=stable@vger.kernel.org \
    --cc=torvalds@linux-foundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
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).