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? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>