diff options
| author | Vladimir Davydov <vdavydov@parallels.com> | 2014-12-12 16:55:13 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-12-13 12:42:47 -0800 |
| commit | 4e701d7b37789d1aeb0015210b373912e5d30733 (patch) | |
| tree | 38257203476057e32f32de241f0d6dc2b7e11891 /mm/memcontrol.c | |
| parent | 900a38f027b37b55ebe157a0cb31de351b91e4e2 (diff) | |
memcg: only check memcg_kmem_skip_account in __memcg_kmem_get_cache
__memcg_kmem_get_cache can recurse if it calls kmalloc (which it does if
the cgroup's kmem cache doesn't exist), because kmalloc may call
__memcg_kmem_get_cache internally again. To avoid the recursion, we use
the task_struct->memcg_kmem_skip_account flag.
However, there's no need checking the flag in memcg_kmem_newpage_charge,
because there's no way how this function could result in recursion, if
called from memcg_kmem_get_cache. So let's remove the redundant code.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 28 |
1 files changed, 0 insertions, 28 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index bb8c237026cc..d9fab72da52e 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2905,34 +2905,6 @@ __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order) *_memcg = NULL; - /* - * Disabling accounting is only relevant for some specific memcg - * internal allocations. Therefore we would initially not have such - * check here, since direct calls to the page allocator that are - * accounted to kmemcg (alloc_kmem_pages and friends) only happen - * outside memcg core. We are mostly concerned with cache allocations, - * and by having this test at memcg_kmem_get_cache, we are already able - * to relay the allocation to the root cache and bypass the memcg cache - * altogether. - * - * There is one exception, though: the SLUB allocator does not create - * large order caches, but rather service large kmallocs directly from - * the page allocator. Therefore, the following sequence when backed by - * the SLUB allocator: - * - * memcg_stop_kmem_account(); - * kmalloc(<large_number>) - * memcg_resume_kmem_account(); - * - * would effectively ignore the fact that we should skip accounting, - * since it will drive us directly to this function without passing - * through the cache selector memcg_kmem_get_cache. Such large - * allocations are extremely rare but can happen, for instance, for the - * cache arrays. We bring this test here. - */ - if (current->memcg_kmem_skip_account) - return true; - memcg = get_mem_cgroup_from_mm(current->mm); if (!memcg_kmem_is_active(memcg)) { |