tree b37d5ba073ccea31328812c74598872d49a85735
parent 073e587ec2cc377867e53d8b8959738a8e16cff6
author KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> 1224386889 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1224517958 -0700

memcg: make page->mapping NULL before uncharge

This patch tries to make page->mapping to be NULL before
mem_cgroup_uncharge_cache_page() is called.

"page->mapping == NULL" is a good check for "whether the page is still
radix-tree or not".  This patch also adds BUG_ON() to
mem_cgroup_uncharge_cache_page();

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>