mm/compaction: reset compaction scanner positions
When the compaction is activated via /proc/sys/vm/compact_memory it would
better scan the whole zone. And some platforms, for instance ARM, have
the start_pfn of a zone at zero. Therefore the first try to compact via
/proc doesn't work. It needs to reset the compaction scanner position
first.
Signed-off-by: Gioh Kim <gioh.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/compaction.c b/mm/compaction.c
index 570426e..e6c4f94 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1605,6 +1605,14 @@
INIT_LIST_HEAD(&cc->freepages);
INIT_LIST_HEAD(&cc->migratepages);
+ /*
+ * When called via /proc/sys/vm/compact_memory
+ * this makes sure we compact the whole zone regardless of
+ * cached scanner positions.
+ */
+ if (cc->order == -1)
+ __reset_isolation_suitable(zone);
+
if (cc->order == -1 || !compaction_deferred(zone, cc->order))
compact_zone(zone, cc);