From: Minchan Kim Date: Fri, 5 Mar 2010 21:41:45 +0000 (-0800) Subject: vmscan: check high watermark after shrink zone X-Git-Tag: firefly_0821_release~9833^2~3000 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=45973d74fd3b1e3e16c025b688a725c7653b1443;p=firefly-linux-kernel-4.4.55.git vmscan: check high watermark after shrink zone Kswapd checks that zone has sufficient pages free via zone_watermark_ok(). If any zone doesn't have enough pages, we set all_zones_ok to zero. !all_zone_ok makes kswapd retry rather than sleeping. I think the watermark check before shrink_zone() is pointless. Only after kswapd has tried to shrink the zone is the check meaningful. Move the check to after the call to shrink_zone(). [akpm@linux-foundation.org: fix comment, layout] Signed-off-by: Minchan Kim Reviewed-by: KOSAKI Motohiro Cc: Mel Gorman Cc: Rik van Riel Reviewed-by: Wu Fengguang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/vmscan.c b/mm/vmscan.c index c26986c85ce0..96ebe6608d5c 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2060,9 +2060,6 @@ loop_again: priority != DEF_PRIORITY) continue; - if (!zone_watermark_ok(zone, order, - high_wmark_pages(zone), end_zone, 0)) - all_zones_ok = 0; temp_priority[i] = priority; sc.nr_scanned = 0; note_zone_scanning_priority(zone, priority); @@ -2102,13 +2099,18 @@ loop_again: total_scanned > sc.nr_reclaimed + sc.nr_reclaimed / 2) sc.may_writepage = 1; - /* - * We are still under min water mark. it mean we have - * GFP_ATOMIC allocation failure risk. Hurry up! - */ - if (!zone_watermark_ok(zone, order, min_wmark_pages(zone), - end_zone, 0)) - has_under_min_watermark_zone = 1; + if (!zone_watermark_ok(zone, order, + high_wmark_pages(zone), end_zone, 0)) { + all_zones_ok = 0; + /* + * We are still under min water mark. This + * means that we have a GFP_ATOMIC allocation + * failure risk. Hurry up! + */ + if (!zone_watermark_ok(zone, order, + min_wmark_pages(zone), end_zone, 0)) + has_under_min_watermark_zone = 1; + } } if (all_zones_ok)