4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Johannes Weiner <[email protected]> [ Upstream commit d450abd81b081d45adb12f303a07dd44b15eb1bc ] PF_MEMALLOC direct reclaimers get throttled on a node when the sum of all free pages in each zone fall below half the min watermark. During the summation, we want to exclude zones that don't have reclaimables. Checking the same pgdat over and over again doesn't make sense. Fixes: 599d0c954f91 ("mm, vmscan: move LRU lists to node") Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Johannes Weiner <[email protected]> Acked-by: Hillf Danton <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Jia He <[email protected]> Cc: Mel Gorman <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- mm/vmscan.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2841,8 +2841,10 @@ static bool allow_direct_reclaim(pg_data for (i = 0; i <= ZONE_NORMAL; i++) { zone = &pgdat->node_zones[i]; - if (!managed_zone(zone) || - pgdat_reclaimable_pages(pgdat) == 0) + if (!managed_zone(zone)) + continue; + + if (!zone_reclaimable_pages(zone)) continue; pfmemalloc_reserve += min_wmark_pages(zone);
