Commit f4aaa8b4 authored Dec 10, 2014 by Johannes Weiner Committed by Linus Torvalds Dec 10, 2014

mm: memcontrol: remove unnecessary PCG_MEM memory charge flag



PCG_MEM is a remnant from an earlier version of 0a31bc97 ("mm:
memcontrol: rewrite uncharge API"), used to tell whether migration cleared
a charge while leaving pc->mem_cgroup valid and PCG_USED set.  But in the
final version, mem_cgroup_migrate() directly uncharges the source page,
rendering this distinction unnecessary.  Remove it.

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>

parent 18eca2e6

include/linux/page_cgroup.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -4,7 +4,6 @@
		enum {
		/* flags for mem_cgroup */
		PCG_USED = 0x01, /* This page is charged to a memcg */
		PCG_MEM = 0x02, /* This page holds a memory charge */
		};

		struct pglist_data;

mm/memcontrol.c

+1 −3

Original line number	Diff line number	Diff line
		@@ -2614,7 +2614,7 @@ static void commit_charge(struct page page, struct mem_cgroup memcg,
		* have the page locked
		*/
		pc->mem_cgroup = memcg;
		pc->flags = PCG_USED \| PCG_MEM;
		pc->flags = PCG_USED;

		if (lrucare)
		unlock_page_lru(page, isolated);
		@@ -6156,8 +6156,6 @@ void mem_cgroup_migrate(struct page oldpage, struct page newpage,
		if (!PageCgroupUsed(pc))
		return;

		VM_BUG_ON_PAGE(!(pc->flags & PCG_MEM), oldpage);

		if (lrucare)
		lock_page_lru(oldpage, &isolated);