mm: compaction: push isolate search base of compact control one pfn ahead
Hillf Danton [Tue, 10 Jan 2012 23:07:59 +0000 (15:07 -0800)]
After isolated the current pfn will no longer be scanned and isolated if
the next round is necessary, so push the isolate_migratepages search base
of the given compact_control one step ahead.

Signed-off-by: Hillf Danton <dhillf@gmail.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/compaction.c

index 1253d7a..e6670c3 100644 (file)
@@ -365,8 +365,10 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
                nr_isolated++;
 
                /* Avoid isolating too much */
-               if (cc->nr_migratepages == COMPACT_CLUSTER_MAX)
+               if (cc->nr_migratepages == COMPACT_CLUSTER_MAX) {
+                       ++low_pfn;
                        break;
+               }
        }
 
        acct_isolated(zone, cc);