]> git.kernelconcepts.de Git - karo-tx-linux.git/commit
mm: page_cgroup: check page_cgroup arrays in lookup_page_cgroup() only when necessary
authorJohannes Weiner <hannes@cmpxchg.org>
Fri, 16 Dec 2011 04:50:37 +0000 (15:50 +1100)
committerStephen Rothwell <sfr@canb.auug.org.au>
Tue, 20 Dec 2011 07:44:02 +0000 (18:44 +1100)
commit19a7119f71107ec7783c7fe1405a236706e95cf9
tree959fde8802f075dfd3b1c3fd9fcad7a2cb0641be
parent4f1b1c36adabbeea7013329cc5174f4f87d2d746
mm: page_cgroup: check page_cgroup arrays in lookup_page_cgroup() only when necessary

lookup_page_cgroup() is usually used only against pages that are used in
userspace.

The exception is the CONFIG_DEBUG_VM-only memcg check from the page
allocator: it can run on pages without page_cgroup descriptors allocated
when the pages are fed into the page allocator for the first time during
boot or memory hotplug.

Include the array check only when CONFIG_DEBUG_VM is set and save the
unnecessary check in production kernels.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
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>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm/page_cgroup.c