Re: [PATCH V4 03/15] mm, compaction: do not count compact_stall if all zones skipped compaction

From: Mel Gorman
Date: Fri Jul 25 2014 - 08:22:58 EST


On Wed, Jul 16, 2014 at 03:48:11PM +0200, Vlastimil Babka wrote:
> The compact_stall vmstat counter counts the number of allocations stalled by
> direct compaction. It does not count when all attempted zones had deferred
> compaction, but it does count when all zones skipped compaction. The skipping
> is decided based on very early check of compaction_suitable(), based on
> watermarks and memory fragmentation. Therefore it makes sense not to count
> skipped compactions as stalls. Moreover, compact_success or compact_fail is
> also already not being counted when compaction was skipped, so this patch
> changes the compact_stall counting to match the other two.
>
> Additionally, restructure __alloc_pages_direct_compact() code for better
> readability.
>
> Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
> Cc: Minchan Kim <minchan@xxxxxxxxxx>
> Cc: Mel Gorman <mgorman@xxxxxxx>
> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> Cc: Michal Nazarewicz <mina86@xxxxxxxxxx>
> Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> Cc: Christoph Lameter <cl@xxxxxxxxx>
> Cc: Rik van Riel <riel@xxxxxxxxxx>
> Cc: David Rientjes <rientjes@xxxxxxxxxx>

Acked-by: Mel Gorman <mgorman@xxxxxxx>

--
Mel Gorman
SUSE Labs
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