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 <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 7b382b9..a52167e 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2518,7 +2518,7 @@
*/
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 @@
* 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 @@
} 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 @@
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 @@
break;
}
- if (!zone_balanced(zone, order, 0, 0)) {
+ if (!zone_balanced(zone, order, 0)) {
classzone_idx = i;
break;
} else {
@@ -3216,7 +3213,7 @@
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 @@
}
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);