From 52e9f87ae8be96a863e44c7d8d7f482fb279dddd Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Thu, 28 Jul 2016 15:46:29 -0700 Subject: [PATCH] mm, page_alloc: wake kswapd based on the highest eligible zone The ac_classzone_idx is used as the basis for waking kswapd and that is based on the preferred zoneref. If the preferred zoneref's first zone is lower than what is available on other nodes, it's possible that kswapd is woken on a zone with only higher, but still eligible, zones. As classzone_idx is strictly adhered to now, it causes a problem because eligible pages are skipped. For example, node 0 has only DMA32 and node 1 has only NORMAL. An allocating context running on node 0 may wake kswapd on node 1 telling it to skip all NORMAL pages. Link: http://lkml.kernel.org/r/1467970510-21195-23-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman Acked-by: Hillf Danton Acked-by: Johannes Weiner Acked-by: Vlastimil Babka Cc: Joonsoo Kim Cc: Michal Hocko Cc: Minchan Kim Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a34d9fcf1339..f2c56a13b065 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3372,7 +3372,7 @@ static void wake_all_kswapds(unsigned int order, const struct alloc_context *ac) for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx, ac->nodemask) { if (last_pgdat != zone->zone_pgdat) - wakeup_kswapd(zone, order, ac_classzone_idx(ac)); + wakeup_kswapd(zone, order, ac->high_zoneidx); last_pgdat = zone->zone_pgdat; } } -- 2.20.1