Messages in this thread | | | Date | Tue, 07 Aug 2012 10:45:25 -0400 | From | Rik van Riel <> | Subject | Re: [PATCH 6/6] mm: have order > 0 compaction start near a pageblock with free pages |
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On 08/07/2012 08:31 AM, Mel Gorman wrote: > commit [7db8889a: mm: have order> 0 compaction start off where it left] > introduced a caching mechanism to reduce the amount work the free page > scanner does in compaction. However, it has a problem. Consider two process > simultaneously scanning free pages > > C > Process A M S F > |---------------------------------------| > Process B M FS
Argh. Good spotting.
> This is not optimal and it can still race but the compact_cached_free_pfn > will be pointing to or very near a pageblock with free pages.
Agreed on the "not optimal", but I also cannot think of a better idea right now. Getting this fixed for 3.6 is important, we can think of future optimizations in San Diego.
> Signed-off-by: Mel Gorman<mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
-- All rights reversed
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