vmscan: low order lumpy reclaim also should use PAGEOUT_IO_SYNC
Commit 33c120ed2843090e2bd316de1588b8bf8b96cbde ("more aggressively use
lumpy reclaim") increased how aggressive lumpy reclaim was by isolating
both active and inactive pages for asynchronous lumpy reclaim on
costly-high-order pages and for cheap-high-order when memory pressure is
high. However, if the system is under heavy pressure and there are dirty
pages, asynchronous IO may not be sufficient to reclaim a suitable page in
time.
This patch causes the caller to enter synchronous lumpy reclaim for
costly-high-order pages and for cheap-high-order pages when under memory
pressure.
Minchan.kim@gmail.com said:
Andy added synchronous lumpy reclaim with
c661b078fd62abe06fd11fab4ac5e4eeafe26b6d. At that time, lumpy reclaim is
not agressive. His intension is just for high-order users.(above
PAGE_ALLOC_COSTLY_ORDER).
After some time, Rik added aggressive lumpy reclaim with
33c120ed2843090e2bd316de1588b8bf8b96cbde. His intention was to do lumpy
reclaim when high-order users and trouble getting a small set of
contiguous pages.
So we also have to add synchronous pageout for small set of contiguous
pages.
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Minchan Kim <Minchan.kim@gmail.com>
Reviewed-by: 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/vmscan.c b/mm/vmscan.c
index 95c08a8..a6b7d14 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1061,6 +1061,19 @@
unsigned long nr_scanned = 0;
unsigned long nr_reclaimed = 0;
struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
+ int lumpy_reclaim = 0;
+
+ /*
+ * If we need a large contiguous chunk of memory, or have
+ * trouble getting a small set of contiguous pages, we
+ * will reclaim both active and inactive pages.
+ *
+ * We use the same threshold as pageout congestion_wait below.
+ */
+ if (sc->order > PAGE_ALLOC_COSTLY_ORDER)
+ lumpy_reclaim = 1;
+ else if (sc->order && priority < DEF_PRIORITY - 2)
+ lumpy_reclaim = 1;
pagevec_init(&pvec, 1);
@@ -1073,19 +1086,7 @@
unsigned long nr_freed;
unsigned long nr_active;
unsigned int count[NR_LRU_LISTS] = { 0, };
- int mode = ISOLATE_INACTIVE;
-
- /*
- * If we need a large contiguous chunk of memory, or have
- * trouble getting a small set of contiguous pages, we
- * will reclaim both active and inactive pages.
- *
- * We use the same threshold as pageout congestion_wait below.
- */
- if (sc->order > PAGE_ALLOC_COSTLY_ORDER)
- mode = ISOLATE_BOTH;
- else if (sc->order && priority < DEF_PRIORITY - 2)
- mode = ISOLATE_BOTH;
+ int mode = lumpy_reclaim ? ISOLATE_BOTH : ISOLATE_INACTIVE;
nr_taken = sc->isolate_pages(sc->swap_cluster_max,
&page_list, &nr_scan, sc->order, mode,
@@ -1122,7 +1123,7 @@
* but that should be acceptable to the caller
*/
if (nr_freed < nr_taken && !current_is_kswapd() &&
- sc->order > PAGE_ALLOC_COSTLY_ORDER) {
+ lumpy_reclaim) {
congestion_wait(WRITE, HZ/10);
/*