From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Subject: 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@xxxxxxxxxxxxxxxxxxx Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Acked-by: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN mm/page_alloc.c~mm-page_alloc-wake-kswapd-based-on-the-highest-eligible-zone mm/page_alloc.c --- a/mm/page_alloc.c~mm-page_alloc-wake-kswapd-based-on-the-highest-eligible-zone +++ a/mm/page_alloc.c @@ -3372,7 +3372,7 @@ static void wake_all_kswapds(unsigned in 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; } } _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
