Messages in this thread | | | Date | Thu, 20 Dec 2012 17:45:50 -0500 | From | Rik van Riel <> | Subject | Re: [PATCH] mm: compaction: Do not accidentally skip pageblocks in the migrate scanner |
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On 12/20/2012 09:22 AM, Mel Gorman wrote: > Compaction uses the ALIGN macro incorrectly with the migrate scanner by > adding pageblock_nr_pages to a PFN. It happened to work when initially > implemented as the starting PFN was also aligned but with caching restarts > and isolating in smaller chunks this is no longer always true. The impact is > that the migrate scanner scans outside its current pageblock. As pfn_valid() > is still checked properly it does not cause any failure and the impact > of the bug is that in some cases it will scan more than necessary when > it crosses a page boundary but by no more than COMPACT_CLUSTER_MAX. It > is highly unlikely this is even measurable but it's still wrong so this > patch addresses the problem. > > Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
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