[PATCH] mm: vmscan: fix malused nr_reclaimed in shrinking zone

Hillf Danton
2012-01-21T14:42:07Z

The value of nr_reclaimed is the amount of pages reclaimed in the current round,
whereas nr_to_reclaim shoud be compared with the amount of pages
reclaimed in all
rounds, so we have to buffer the pages reclaimed in the past rounds for correct
comparison.

Signed-off-by: Hillf Danton <dhillf@gmail.com>
---

--- a/mm/vmscan.c Sat Jan 14 14:02:20 2012
+++ b/mm/vmscan.c Sat Jan 21 22:23:48 2012
@@ -2081,13 +2081,15 @@ static void shrink_mem_cgroup_zone(int p
struct scan_control *sc)
{
unsigned long nr[NR_LRU_LISTS];
+ unsigned long reclaimed = 0;
unsigned long nr_to_scan;
enum lru_list lru;
- unsigned long nr_reclaimed, nr_scanned;
+ unsigned long nr_reclaimed = 0, nr_scanned;
unsigned long nr_to_reclaim = sc->nr_to_reclaim;
struct blk_plug plug;

restart:
+ reclaimed += nr_reclaimed;
nr_reclaimed = 0;
nr_scanned = sc->nr_scanned;
get_scan_count(mz, sc, nr, priority);
@@ -2113,7 +2115,8 @@ restart:
* with multiple processes reclaiming pages, the total
* freeing target can get unreasonably large.
*/
- if (nr_reclaimed >= nr_to_reclaim && priority < DEF_PRIORITY)
+ if ((nr_reclaimed + reclaimed) >= nr_to_reclaim &&
+ priority < DEF_PRIORITY)
break;
}
blk_finish_plug(&plug);