From 31483b6ad205784d3a82240865135bef5c97c105 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Thu, 28 Jul 2016 15:45:46 -0700 Subject: mm, vmscan: remove balance gap The balance gap was introduced to apply equal pressure to all zones when reclaiming for a higher zone. With node-based LRU, the need for the balance gap is removed and the code is dead so remove it. [vbabka@suse.cz: Also remove KSWAPD_ZONE_BALANCE_GAP_RATIO] Link: http://lkml.kernel.org/r/1467970510-21195-9-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman Acked-by: Vlastimil Babka Cc: Hillf Danton Acked-by: Johannes Weiner Cc: Joonsoo Kim Cc: Michal Hocko Cc: Minchan Kim Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) (limited to 'mm') diff --git a/mm/vmscan.c b/mm/vmscan.c index 7b382b90b145..a52167eabc96 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2518,7 +2518,7 @@ static bool shrink_node(pg_data_t *pgdat, struct scan_control *sc, */ static inline bool compaction_ready(struct zone *zone, int order, int classzone_idx) { - unsigned long balance_gap, watermark; + unsigned long watermark; bool watermark_ok; /* @@ -2527,9 +2527,7 @@ static inline bool compaction_ready(struct zone *zone, int order, int classzone_ * there is a buffer of free pages available to give compaction * a reasonable chance of completing and allocating the page */ - balance_gap = min(low_wmark_pages(zone), DIV_ROUND_UP( - zone->managed_pages, KSWAPD_ZONE_BALANCE_GAP_RATIO)); - watermark = high_wmark_pages(zone) + balance_gap + (2UL << order); + watermark = high_wmark_pages(zone) + (2UL << order); watermark_ok = zone_watermark_ok_safe(zone, 0, watermark, classzone_idx); /* @@ -3000,10 +2998,9 @@ static void age_active_anon(struct pglist_data *pgdat, } while (memcg); } -static bool zone_balanced(struct zone *zone, int order, - unsigned long balance_gap, int classzone_idx) +static bool zone_balanced(struct zone *zone, int order, int classzone_idx) { - unsigned long mark = high_wmark_pages(zone) + balance_gap; + unsigned long mark = high_wmark_pages(zone); return zone_watermark_ok_safe(zone, order, mark, classzone_idx); } @@ -3045,7 +3042,7 @@ static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order, long remaining, if (!populated_zone(zone)) continue; - if (zone_balanced(zone, order, 0, classzone_idx)) + if (zone_balanced(zone, order, classzone_idx)) return true; } @@ -3148,7 +3145,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx) break; } - if (!zone_balanced(zone, order, 0, 0)) { + if (!zone_balanced(zone, order, 0)) { classzone_idx = i; break; } else { @@ -3216,7 +3213,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx) if (!populated_zone(zone)) continue; - if (zone_balanced(zone, sc.order, 0, classzone_idx)) { + if (zone_balanced(zone, sc.order, classzone_idx)) { clear_bit(PGDAT_CONGESTED, &pgdat->flags); clear_bit(PGDAT_DIRTY, &pgdat->flags); goto out; @@ -3427,7 +3424,7 @@ void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx) } if (!waitqueue_active(&pgdat->kswapd_wait)) return; - if (zone_balanced(zone, order, 0, 0)) + if (zone_balanced(zone, order, 0)) return; trace_mm_vmscan_wakeup_kswapd(pgdat->node_id, zone_idx(zone), order); -- cgit v1.2.3