On Fri, 13 May 2011 12:10:30 +0900 KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote: > > 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 1st. > > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> > --- > mm/vmscan.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > Index: mmotm-May11/mm/vmscan.c > =================================================================== > --- mmotm-May11.orig/mm/vmscan.c > +++ mmotm-May11/mm/vmscan.c > @@ -941,7 +941,8 @@ 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 (scanning_global_lru(sc) && > + nr_dirty == nr_congested && nr_dirty != 0) > zone_set_flag(zone, ZONE_CONGESTED); > nit: which is more probable? nr_dirty==nr_congested or scanning_global_lru(sc)? If the user is actually _using_ memcg then --- a/mm/vmscan.c~a +++ a/mm/vmscan.c @@ -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_congested && scanning_global_lru(sc) && nr_dirty) zone_set_flag(zone, ZONE_CONGESTED); free_page_list(&free_pages); is more efficient. If the user isn't using memcg then your patch is faster? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx 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>