From: Mel Gorman <mgorman@suse.de>
Date: Fri, 28 Sep 2012 00:19:48 +0000 (+1000)
Subject: mm: compaction: cache if a pageblock was scanned and no pages were isolated -fix2
X-Git-Tag: next-20121004~1^2~236
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=ad27398b818479461b9901c815a331ddd0b34000;p=karo-tx-linux.git

mm: compaction: cache if a pageblock was scanned and no pages were isolated -fix2

The clearing of PG_migrate_skip potentially takes a long time if the
zone is massive. Be safe and check if it needs to reschedule.

This is a fix for
mm-compaction-cache-if-a-pageblock-was-scanned-and-no-pages-were-isolated.patch

Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/compaction.c b/mm/compaction.c
index e54027411a6c..f7a5ff5af9f5 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -85,6 +85,9 @@ static void reset_isolation_suitable(struct zone *zone)
 	/* Walk the zone and mark every pageblock as suitable for isolation */
 	for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
 		struct page *page;
+
+		cond_resched();
+
 		if (!pfn_valid(pfn))
 			continue;