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Date: Sun, 14 Jun 2020 14:38:58 +0800
From: Muchun Song <songmuchun@...edance.com>
To: cl@...ux.com, penberg@...nel.org, rientjes@...gle.com,
iamjoonsoo.kim@....com, akpm@...ux-foundation.org
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org,
Muchun Song <songmuchun@...edance.com>
Subject: [PATCH] mm/slab: Add a __GFP_ACCOUNT GFP flag check for slab allocation
When a kmem_cache is initialized with SLAB_ACCOUNT slab flag, we must
not call kmem_cache_alloc with __GFP_ACCOUNT GFP flag. In this case,
we can be accounted to kmemcg twice. This is not correct. So we add a
__GFP_ACCOUNT GFP flag check for slab allocation.
We also introduce a new helper named fixup_gfp_flags to do that check.
We can reuse the fixup_gfp_flags for SLAB/SLUB.
Signed-off-by: Muchun Song <songmuchun@...edance.com>
---
mm/slab.c | 10 +---------
mm/slab.h | 21 +++++++++++++++++++++
mm/slub.c | 10 +---------
3 files changed, 23 insertions(+), 18 deletions(-)
diff --git a/mm/slab.c b/mm/slab.c
index 9350062ffc1a..6e0110bef2d6 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -126,8 +126,6 @@
#include <trace/events/kmem.h>
-#include "internal.h"
-
#include "slab.h"
/*
@@ -2579,13 +2577,7 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep,
* Be lazy and only check for valid flags here, keeping it out of the
* critical path in kmem_cache_alloc().
*/
- if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
- gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
- flags &= ~GFP_SLAB_BUG_MASK;
- pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
- invalid_mask, &invalid_mask, flags, &flags);
- dump_stack();
- }
+ flags = fixup_gfp_flags(cachep, flags);
WARN_ON_ONCE(cachep->ctor && (flags & __GFP_ZERO));
local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
diff --git a/mm/slab.h b/mm/slab.h
index 815e4e9a94cd..0b91f2a7b033 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -109,6 +109,7 @@ struct memcg_cache_params {
#include <linux/kmemleak.h>
#include <linux/random.h>
#include <linux/sched/mm.h>
+#include "internal.h"
/*
* State of the slab allocator.
@@ -627,6 +628,26 @@ struct kmem_cache_node {
};
+static inline gfp_t fixup_gfp_flags(struct kmem_cache *s, gfp_t flags)
+{
+ gfp_t invalid_mask = 0;
+
+ if (unlikely(flags & GFP_SLAB_BUG_MASK))
+ invalid_mask |= flags & GFP_SLAB_BUG_MASK;
+
+ if (unlikely(flags & __GFP_ACCOUNT && s->flags & SLAB_ACCOUNT))
+ invalid_mask |= __GFP_ACCOUNT;
+
+ if (unlikely(invalid_mask)) {
+ flags &= ~invalid_mask;
+ pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
+ invalid_mask, &invalid_mask, flags, &flags);
+ dump_stack();
+ }
+
+ return flags;
+}
+
static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
{
return s->node[node];
diff --git a/mm/slub.c b/mm/slub.c
index b8f798b50d44..49b5cb7da318 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -37,8 +37,6 @@
#include <trace/events/kmem.h>
-#include "internal.h"
-
/*
* Lock order:
* 1. slab_mutex (Global Mutex)
@@ -1745,13 +1743,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
{
- if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
- gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
- flags &= ~GFP_SLAB_BUG_MASK;
- pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
- invalid_mask, &invalid_mask, flags, &flags);
- dump_stack();
- }
+ flags = fixup_gfp_flags(s, flags);
return allocate_slab(s,
flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
--
2.11.0
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