From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Subject: mm, vmscan: by default have direct reclaim only shrink once per node Direct reclaim iterates over all zones in the zonelist and shrinking them but this is in conflict with node-based reclaim. In the default case, only shrink once per node. Link: http://lkml.kernel.org/r/1467970510-21195-11-git-send-email-mgorman@xxxxxxxxxxxxxxxxxxx Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Cc: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx> 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/vmscan.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) diff -puN mm/vmscan.c~mm-vmscan-by-default-have-direct-reclaim-only-shrink-once-per-node mm/vmscan.c --- a/mm/vmscan.c~mm-vmscan-by-default-have-direct-reclaim-only-shrink-once-per-node +++ a/mm/vmscan.c @@ -2552,14 +2552,6 @@ static inline bool compaction_ready(stru * try to reclaim pages from zones which will satisfy the caller's allocation * request. * - * We reclaim from a zone even if that zone is over high_wmark_pages(zone). - * Because: - * a) The caller may be trying to free *extra* pages to satisfy a higher-order - * allocation or - * b) The target zone may be at high_wmark_pages(zone) but the lower zones - * must go *over* high_wmark_pages(zone) to satisfy the `incremental min' - * zone defense algorithm. - * * If a zone is deemed to be full of pinned pages then just give it a light * scan then give up on it. */ @@ -2571,6 +2563,7 @@ static void shrink_zones(struct zonelist unsigned long nr_soft_scanned; gfp_t orig_mask; enum zone_type classzone_idx; + pg_data_t *last_pgdat = NULL; /* * If the number of buffer_heads in the machine exceeds the maximum @@ -2630,6 +2623,15 @@ static void shrink_zones(struct zonelist } /* + * Shrink each node in the zonelist once. If the + * zonelist is ordered by zone (not the default) then a + * node may be shrunk multiple times but in that case + * the user prefers lower zones being preserved. + */ + if (zone->zone_pgdat == last_pgdat) + continue; + + /* * This steals pages from memory cgroups over softlimit * and returns the number of reclaimed pages and * scanned pages. This works for global memory pressure @@ -2644,6 +2646,10 @@ static void shrink_zones(struct zonelist /* need some check for avoid more shrink_zone() */ } + /* See comment about same check for global reclaim above */ + if (zone->zone_pgdat == last_pgdat) + continue; + last_pgdat = zone->zone_pgdat; shrink_node(zone->zone_pgdat, sc, classzone_idx); } _ -- 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
