On 05/29/2011 02:13 PM, Minchan Kim wrote:
In async mode, compaction doesn't migrate dirty or writeback pages. So, it's meaningless to pick the page and re-add it to lru list. Of course, when we isolate the page in compaction, the page might be dirty or writeback but when we try to migrate the page, the page would be not dirty, writeback. So it could be migrated. But it's very unlikely as isolate and migration cycle is much faster than writeout. So, this patch helps cpu and prevent unnecessary LRU churning. Reviewed-by: KAMEZAWA Hiroyuki<kamezawa.hiroyu@xxxxxxxxxxxxxx> Reviewed-by: KOSAKI Motohiro<kosaki.motohiro@xxxxxxxxxxxxxx> Acked-by: Johannes Weiner<hannes@xxxxxxxxxxx> Acked-by: Mel Gorman<mgorman@xxxxxxx> Cc: Rik van Riel<riel@xxxxxxxxxx> Cc: Andrea Arcangeli<aarcange@xxxxxxxxxx> Signed-off-by: Minchan Kim<minchan.kim@xxxxxxxxx>
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