Messages in this thread | | | Date | Thu, 28 Jun 2012 10:18:50 +0900 | From | Minchan Kim <> | Subject | Re: excessive CPU utilization by isolate_freepages? |
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On 06/28/2012 10:06 AM, David Rientjes wrote:
> On Thu, 28 Jun 2012, Minchan Kim wrote: > >>>>>>> https://lkml.org/lkml/2012/6/21/30 >>>>> >>> Not sure if Jim is using memcg; if not, then this won't be helpful. >>> >> >> >> It doesn't related to memcg. >> if compaction_alloc can't find suitable migration target, it returns NULL. >> Then, migrate_pages should be exit. >> > > If isolate_freepages() is going to fail, then this zone should have been > skipped when checking for compaction_suitable(). In Jim's perf output, > compaction_suitable() returns COMPACT_CONTINUE for a transparent hugepage. > Why is zone_watermark_ok(zone, 0 low_wmark + 1024, 0, 0) succeeding if > isolate_freepages() is going to fail? >
zone_watermark_ok doesn't consider migratetype but suitable_migrate_target does consider one.
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-- Kind regards, Minchan Kim
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