On Wed, Aug 31, 2011 at 07:13:34PM +0900, Minchan Kim wrote: > On Wed, Aug 31, 2011 at 6:08 PM, Johannes Weiner <jweiner@xxxxxxxxxx> wrote: > > Reclaim decides to skip scanning an active list when the corresponding > > inactive list is above a certain size in comparison to leave the > > assumed working set alone while there are still enough reclaim > > candidates around. > > > > The memcg implementation of comparing those lists instead reports > > whether the whole memcg is low on the requested type of inactive > > pages, considering all nodes and zones. > > > > This can lead to an oversized active list not being scanned because of > > the state of the other lists in the memcg, as well as an active list > > being scanned while its corresponding inactive list has enough pages. > > > > Not only is this wrong, it's also a scalability hazard, because the > > global memory state over all nodes and zones has to be gathered for > > each memcg and zone scanned. > > > > Make these calculations purely based on the size of the two LRU lists > > that are actually affected by the outcome of the decision. > > > > Signed-off-by: Johannes Weiner <jweiner@xxxxxxxxxx> > > Cc: Rik van Riel <riel@xxxxxxxxxx> > > Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> > > Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> > > Cc: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> > > Cc: Balbir Singh <bsingharora@xxxxxxxxx> > > Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx> Thank you. > I can't understand why memcg is designed for considering all nodes and zones. > Is it a mistake or on purpose? > Maybe Kame or Balbir can answer it. > > Anyway, this change does make sense to me. > > Nitpick: Please remove inactive_ratio in Documentation/cgroups/memory.txt. > I think it would be better to separate it into another patch. Good catch. --- Subject: [patch] memcg: skip scanning active lists based on individual fix Also ditch the documentation note for the removed stats value. Signed-off-by: Johannes Weiner <jweiner@xxxxxxxxxx> --- diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt index 06eb6d9..cc0ebc5 100644 --- a/Documentation/cgroups/memory.txt +++ b/Documentation/cgroups/memory.txt @@ -418,7 +418,6 @@ total_unevictable - sum of all children's "unevictable" # The following additional stats are dependent on CONFIG_DEBUG_VM. -inactive_ratio - VM internal parameter. (see mm/page_alloc.c) recent_rotated_anon - VM internal parameter. (see mm/vmscan.c) recent_rotated_file - VM internal parameter. (see mm/vmscan.c) recent_scanned_anon - VM internal parameter. (see mm/vmscan.c) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>