From: Johannes Weiner <hannes@cmpxchg.org>
Date: Wed, 10 Dec 2014 23:44:02 +0000 (-0800)
Subject: mm: memcontrol: remove unnecessary PCG_USED pc->mem_cgroup valid flag
X-Git-Tag: omap-for-v3.20/drop-legacy-3517~139^2~129
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2983331575bfb248abfb02efb5140b4a299e3f45;p=pandora-kernel.git

mm: memcontrol: remove unnecessary PCG_USED pc->mem_cgroup valid flag

pc->mem_cgroup had to be left intact after uncharge for the final LRU
removal, and !PCG_USED indicated whether the page was uncharged.  But
since commit 0a31bc97c80c ("mm: memcontrol: rewrite uncharge API") pages
are uncharged after the final LRU removal.  Uncharge can simply clear
the pointer and the PCG_USED/PageCgroupUsed sites can test that instead.

Because this is the last page_cgroup flag, this patch reduces the memcg
per-page overhead to a single pointer.

[akpm@linux-foundation.org: remove unneeded initialization of `memcg', per Michal]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

Reading git-diff-tree failed