Commit aeef4b83 authored Jun 04, 2014 by David Rientjes Committed by Linus Torvalds Jun 04, 2014

mm, compaction: terminate async compaction when rescheduling



Async compaction terminates prematurely when need_resched(), see
compact_checklock_irqsave().  This can never trigger, however, if the
cond_resched() in isolate_migratepages_range() always takes care of the
scheduling.

If the cond_resched() actually triggers, then terminate this pageblock
scan for async compaction as well.

Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 75f30861

mm/compaction.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -494,8 +494,13 @@ isolate_migratepages_range(struct zone zone, struct compact_control cc,
		return 0;
		}

		if (cond_resched()) {
		/* Async terminates prematurely on need_resched() */
		if (cc->mode == MIGRATE_ASYNC)
		return 0;
		}

		/* Time to isolate some pages for migration */
		cond_resched();
		for (; low_pfn < end_pfn; low_pfn++) {
		/* give a chance to irqs before checking need_resched() */
		if (locked && !(low_pfn % SWAP_CLUSTER_MAX)) {

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