Messages in this thread | | | Date | Thu, 16 Jul 2009 12:19:56 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [PATCH -mm] throttle direct reclaim when too many pages are isolated already |
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On Wed, 15 Jul 2009 22:38:53 -0400 Rik van Riel <riel@redhat.com> wrote:
> When way too many processes go into direct reclaim, it is possible > for all of the pages to be taken off the LRU. One result of this > is that the next process in the page reclaim code thinks there are > no reclaimable pages left and triggers an out of memory kill. > > One solution to this problem is to never let so many processes into > the page reclaim path that the entire LRU is emptied. Limiting the > system to only having half of each inactive list isolated for > reclaim should be safe. > > Signed-off-by: Rik van Riel <riel@redhat.com> > --- > This patch goes on top of Kosaki's "Account the number of isolated pages" > patch series. > > mm/vmscan.c | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > Index: mmotm/mm/vmscan.c > =================================================================== > --- mmotm.orig/mm/vmscan.c 2009-07-08 21:37:01.000000000 -0400 > +++ mmotm/mm/vmscan.c 2009-07-08 21:39:02.000000000 -0400 > @@ -1035,6 +1035,27 @@ int isolate_lru_page(struct page *page) > } > > /* > + * Are there way too many processes in the direct reclaim path already? > + */ > +static int too_many_isolated(struct zone *zone, int file) > +{ > + unsigned long inactive, isolated; > + > + if (current_is_kswapd()) > + return 0; > + > + if (file) { > + inactive = zone_page_state(zone, NR_INACTIVE_FILE); > + isolated = zone_page_state(zone, NR_ISOLATED_FILE); > + } else { > + inactive = zone_page_state(zone, NR_INACTIVE_ANON); > + isolated = zone_page_state(zone, NR_ISOLATED_ANON); > + } > + > + return isolated > inactive; > +}
Why this means "too much" ? And, could you put this check under scanning_global_lru(sc) ?
Thanks, -Kame
> + > +/* > * shrink_inactive_list() is a helper for shrink_zone(). It returns the number > * of reclaimed pages > */ > @@ -1049,6 +1070,10 @@ static unsigned long shrink_inactive_lis > struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc); > int lumpy_reclaim = 0; > > + while (unlikely(too_many_isolated(zone, file))) { > + schedule_timeout_interruptible(HZ/10); > + } > + > /* > * If we need a large contiguous chunk of memory, or have > * trouble getting a small set of contiguous pages, we > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> >
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