Commit d6c438b6 authored May 17, 2011 by KAMEZAWA Hiroyuki Committed by Linus Torvalds May 18, 2011

memcg: fix zone congestion



ZONE_CONGESTED should be a state of global memory reclaim.  If not, a busy
memcg sets this and give unnecessary throttoling in wait_iff_congested()
against memory recalim in other contexts.  This makes system performance
bad.

I'll think about "memcg is congested!" flag is required or not, later.
But this fix is required first.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: Ying Han <yinghan@google.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent d5f33d45

mm/vmscan.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -937,7 +937,7 @@ keep_lumpy:
		* back off and wait for congestion to clear because further reclaim
		* will encounter the same problem
		*/
		if (nr_dirty == nr_congested && nr_dirty != 0)
		if (nr_dirty && nr_dirty == nr_congested && scanning_global_lru(sc))
		zone_set_flag(zone, ZONE_CONGESTED);

		free_page_list(&free_pages);

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