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authorVladimir Davydov <vdavydov@parallels.com>2015-05-15 01:16:55 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-05-15 03:55:51 +0300
commit8f4fc071b1926d0b20336e2b3f8ab85c94c734c5 (patch)
treebfd0b008df7bdb9353fbe7a998485e990a9923f3 /mm
parent4933f55fe72c86e57efc454dd6e673c7f17af5a3 (diff)
downloadlinux-8f4fc071b1926d0b20336e2b3f8ab85c94c734c5.tar.xz
gfp: add __GFP_NOACCOUNT
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. Note, since in case of kmemleak enabled each kmalloc implies yet another allocation from the kmemleak_object cache, we add __GFP_NOACCOUNT to gfp_kmemleak_mask. Alternatively, we could introduce a per kmem cache flag disabling accounting for all allocations of a particular kind, but (a) we would not be able to bypass accounting for kmalloc then and (b) a kmem cache with this flag set could not be merged with a kmem cache without this flag, which would increase the number of global caches and therefore fragmentation even if the memory cgroup controller is not used. Despite its generic name, currently __GFP_NOACCOUNT disables accounting only for kmem allocations while user page allocations are always charged. To catch abusing of this flag, a warning is issued on an attempt of passing it to mem_cgroup_try_charge. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Tejun Heo <tj@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Greg Thelen <gthelen@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: <stable@vger.kernel.org> [4.0.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/kmemleak.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 5405aff5a590..f0fe4f2c1fa7 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -115,7 +115,8 @@
#define BYTES_PER_POINTER sizeof(void *)
/* GFP bitmask for kmemleak internal allocations */
-#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC)) | \
+#define gfp_kmemleak_mask(gfp) (((gfp) & (GFP_KERNEL | GFP_ATOMIC | \
+ __GFP_NOACCOUNT)) | \
__GFP_NORETRY | __GFP_NOMEMALLOC | \
__GFP_NOWARN)