The patch titled
vmscan: check high watermark after shrink zone
has been added to the -mm tree. Its filename is
vmscan-check-high-watermark-after-shrink-zone.patch
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------------------------------------------------------
Subject: vmscan: check high watermark after shrink zone
From: Minchan Kim <minchan.kim@xxxxxxxxx>
Kswapd checks that zone has sufficient pages free via zone_watermark_ok().
If any zone doesn't have enough pages, we set all_zones_ok to zero.
!all_zone_ok makes kswapd retry rather than sleeping.
I think the watermark check before shrink_zone() is pointless. Only after
kswapd has tried to shrink the zone is the check meaningful.
Move the check to after the call to shrink_zone().
Signed-off-by: Minchan Kim <minchan.kim@xxxxxxxxx>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Reviewed-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
diff -puN mm/vmscan.c~vmscan-check-high-watermark-after-shrink-zone mm/vmscan.c
--- a/mm/vmscan.c~vmscan-check-high-watermark-after-shrink-zone
+++ a/mm/vmscan.c
@@ -2060,9 +2060,6 @@ loop_again:
priority != DEF_PRIORITY)
continue;
- if (!zone_watermark_ok(zone, order,
- high_wmark_pages(zone), end_zone, 0))
- all_zones_ok = 0;
temp_priority[i] = priority;
sc.nr_scanned = 0;
note_zone_scanning_priority(zone, priority);
@@ -2102,13 +2099,17 @@ loop_again:
total_scanned > sc.nr_reclaimed + sc.nr_reclaimed / 2)
sc.may_writepage = 1;
- /*
- * We are still under min water mark. it mean we have
- * GFP_ATOMIC allocation failure risk. Hurry up!
- */
- if (!zone_watermark_ok(zone, order, min_wmark_pages(zone),
- end_zone, 0))
- has_under_min_watermark_zone = 1;
+ if (!zone_watermark_ok(zone, order,
+ high_wmark_pages(zone), end_zone, 0)) {
+ all_zones_ok = 0;
+ /*
+ * We are still under min water mark. it mean we have
+ * GFP_ATOMIC allocation failure risk. Hurry up!
+ */
+ if (!zone_watermark_ok(zone, order, min_wmark_pages(zone),
+ end_zone, 0))
+ has_under_min_watermark_zone = 1;
+ }
}
if (all_zones_ok)
_
Patches currently in -mm which might be from minchan.kim@xxxxxxxxx are
origin.patch
page-allocator-fix-update-nr_free_pages-only-as-necessary.patch
vmscan-kswapd-dont-retry-balance_pgdat-if-all-zones-are-unreclaimable.patch
mm-clean-up-mm_counter.patch
mm-avoid-false-sharing-of-mm_counter.patch
mm-count-swap-usage.patch
mm-count-swap-usage-checkpatch-fixes.patch
mm-add-lowmem-detection-logic.patch
mm-count-lowmem-rss.patch
vmscan-check-high-watermark-after-shrink-zone.patch
vmscan-check-high-watermark-after-shrink-zone-fix.patch
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