Not all kmem allocations should be accounted to memcg. The following
patch gives an example when accounting of a certain type of allocations
to memcg can effectively result in a memory leak. This patch adds the
__GFP_NOACCOUNT flag which if passed to kmalloc and friends will force
the allocation to go through the root cgroup. It will be used by the
next patch.
Signed-off-by: Vladimir Davydov <vdavy...@parallels.com>
---
include/linux/gfp.h | 2 ++
include/linux/memcontrol.h | 4 ++--
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 4d66a5daf0bf..b26f7f11d394 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -30,6 +30,7 @@ struct vm_area_struct;
#define ___GFP_HARDWALL 0x20000u
#define ___GFP_THISNODE 0x40000u
#define ___GFP_RECLAIMABLE 0x80000u
+#define ___GFP_NOACCOUNT 0x100000u
#define ___GFP_NOTRACK 0x200000u
#define ___GFP_NO_KSWAPD 0x400000u
#define ___GFP_OTHER_NODE 0x800000u
@@ -85,6 +86,7 @@ struct vm_area_struct;
#define __GFP_HARDWALL ((__force gfp_t)___GFP_HARDWALL) /* Enforce hardwall
cpuset memory allocs */
#define __GFP_THISNODE ((__force gfp_t)___GFP_THISNODE)/* No fallback, no
policies */
#define __GFP_RECLAIMABLE ((__force gfp_t)___GFP_RECLAIMABLE) /* Page is
reclaimable */
+#define __GFP_NOACCOUNT ((__force gfp_t)___GFP_NOACCOUNT) /* Don't
account to kmemcg */
#define __GFP_NOTRACK ((__force gfp_t)___GFP_NOTRACK) /* Don't track with
kmemcheck */
#define __GFP_NO_KSWAPD ((__force gfp_t)___GFP_NO_KSWAPD)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 91feab1605a8..77577b8c6cd6 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -496,7 +496,7 @@ memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup
**memcg, int order)
* res_counter_charge_nofail, but we hope those allocations are rare,
* and won't be worth the trouble.
*/
- if (gfp & __GFP_NOFAIL)
+ if (gfp & (__GFP_NOFAIL|__GFP_NOACCOUNT))
return true;
if (in_interrupt() || (!current->mm) || (current->flags & PF_KTHREAD))
return true;
@@ -552,7 +552,7 @@ memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
{
if (!memcg_kmem_enabled())
return cachep;
- if (gfp & __GFP_NOFAIL)
+ if (gfp & (__GFP_NOFAIL|__GFP_NOACCOUNT))
return cachep;
if (in_interrupt() || (!current->mm) || (current->flags & PF_KTHREAD))
return cachep;
--
1.7.10.4
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