[PATCH] compaction: fix deferring compaction mistake

[PATCH] compaction: fix deferring compaction mistake

[Minchan Kim]

[1] fixed bad deferring policy but made mistake about checking
compact_order_failed in __compact_pgdat so it can't update
compact_order_failed with new order. It ends up preventing working
of deffering policy rightly. This patch fixes it.

[1] aff62249, vmscan: only defer compaction for failed order and higher

Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
 mm/compaction.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index e78cb96..b6984e2 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -861,7 +861,7 @@ static int __compact_pgdat(pg_data_t *pgdat, struct compact_control *cc)
 		if (cc->order > 0) {
 			int ok = zone_watermark_ok(zone, cc->order,
 						low_wmark_pages(zone), 0, 0);
-			if (ok && cc->order > zone->compact_order_failed)
+			if (ok && cc->order >= zone->compact_order_failed)
 				zone->compact_order_failed = cc->order + 1;
 			/* Currently async compaction is never deferred. */
 			else if (!ok && cc->sync)
-- 
1.7.9.5

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Re: [PATCH] compaction: fix deferring compaction mistake

[Rik van Riel]

On 08/07/2012 08:57 PM, Minchan Kim wrote:
> [1] fixed bad deferring policy but made mistake about checking
> compact_order_failed in __compact_pgdat so it can't update
> compact_order_failed with new order. It ends up preventing working
> of deffering policy rightly. This patch fixes it.

Good catch.

> [1] aff62249, vmscan: only defer compaction for failed order and higher
>
> Cc: Rik van Riel <riel@redhat.com>
> Cc: Mel Gorman <mel@csn.ul.ie>
> Signed-off-by: Minchan Kim <minchan@kernel.org>

Reviewed-by: Rik van Riel <riel@redhat.com>

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Re: [PATCH] compaction: fix deferring compaction mistake

[Mel Gorman]

On Wed, Aug 08, 2012 at 09:57:44AM +0900, Minchan Kim wrote:
> [1] fixed bad deferring policy but made mistake about checking
> compact_order_failed in __compact_pgdat so it can't update
> compact_order_failed with new order. It ends up preventing working
> of deffering policy rightly. This patch fixes it.
> 
> [1] aff62249, vmscan: only defer compaction for failed order and higher
> 
> Cc: Rik van Riel <riel@redhat.com>
> Cc: Mel Gorman <mel@csn.ul.ie>
> Signed-off-by: Minchan Kim <minchan@kernel.org>

Acked-by: Mel Gorman <mel@csn.ul.ie>

-- 
Mel Gorman
SUSE Labs

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