]> git.openfabrics.org - ~shefty/rdma-dev.git/commit
mm: memcg: lookup_page_cgroup (almost) never returns NULL
authorJohannes Weiner <jweiner@redhat.com>
Fri, 13 Jan 2012 01:18:38 +0000 (17:18 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 13 Jan 2012 04:13:06 +0000 (20:13 -0800)
commitcfa449461e67b60df986170eecb089831fa9e49a
treeff40cff591e27250b91b2f1fb4409875f397b048
parent0e574a932d2cab8eb3b02d21feb59f2c09154738
mm: memcg: lookup_page_cgroup (almost) never returns NULL

Pages have their corresponding page_cgroup descriptors set up before
they are used in userspace, and thus managed by a memory cgroup.

The only time where lookup_page_cgroup() can return NULL is in the
CONFIG_DEBUG_VM-only page sanity checking code that executes while
feeding pages into the page allocator for the first time.

Remove the NULL checks against lookup_page_cgroup() results from all
callsites where we know that corresponding page_cgroup descriptors must
be allocated, and add a comment to the callsite that actually does have
to check the return value.

[hughd@google.com: stop oops in mem_cgroup_update_page_stat()]
Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/memcontrol.c