path: root/mm
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authorDavid Rientjes <rientjes@google.com>2013-09-30 13:45:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-30 14:31:01 -0700
commitf6ea3adb70b20ae36277a1b0eaaf4da9f6479a28 (patch)
tree9d21f9dfff81d06902db1bdd18d0bd575c06065c /mm
parent72023656961b8c81a168a7a6762d589339d0d7ec (diff)
mm/compaction.c: periodically schedule when freeing pages
We've been getting warnings about an excessive amount of time spent allocating pages for migration during memory compaction without scheduling. isolate_freepages_block() already periodically checks for contended locks or the need to schedule, but isolate_freepages() never does. When a zone is massively long and no suitable targets can be found, this iteration can be quite expensive without ever doing cond_resched(). Check periodically for the need to reschedule while the compaction free scanner iterates. Signed-off-by: David Rientjes <rientjes@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
1 files changed, 7 insertions, 0 deletions
diff --git a/mm/compaction.c b/mm/compaction.c
index c43789388cd8..b5326b141a25 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -677,6 +677,13 @@ static void isolate_freepages(struct zone *zone,
pfn -= pageblock_nr_pages) {
unsigned long isolated;
+ /*
+ * This can iterate a massively long zone without finding any
+ * suitable migration targets, so periodically check if we need
+ * to schedule.
+ */
+ cond_resched();
if (!pfn_valid(pfn))