Messages in this thread | | | Date | Thu, 2 Jun 2011 11:38:20 +0100 | From | Mel Gorman <> | Subject | Re: [PATCH v2] mm: compaction: fix special case -1 order checks |
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On Mon, May 30, 2011 at 05:24:50PM +0200, Michal Hocko wrote: > <SNIP> > mm: compaction: fix special case -1 order checks > > 56de7263 (mm: compaction: direct compact when a high-order allocation > fails) introduced a check for cc->order == -1 in compact_finished. We > should continue compacting in that case because the request came from > userspace and there is no particular order to compact for. > Similar check has been added by 82478fb7 (mm: compaction: > prevent division-by-zero during user-requested compaction) for > compaction_suitable. > > The check is, however, done after zone_watermark_ok which uses order as > a right hand argument for shifts. Not only watermark check is pointless > if we can break out without it but it also uses 1 << -1 which is not > well defined (at least from C standard). Let's move the -1 check above > zone_watermark_ok. > > [Minchan Kim <minchan.kim@gmail.com> - caught compaction_suitable] > Signed-off-by: Michal Hocko <mhocko@suse.cz> > Cc: Mel Gorman <mgorman@suse.de>
Acked-by: Mel Gorman <mgorman@suse.de>
-- Mel Gorman SUSE Labs
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