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authorRik van Riel <riel@redhat.com>2009-09-22 02:01:38 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-22 16:17:29 +0200
commit35cd78156c499ef83f60605e4643d5a98fef14fd (patch)
tree67cdc9019d4b110b9d57634bd347c8dad6bf8346
parentmm: vmstat: add isolate pages (diff)
downloadlinux-35cd78156c499ef83f60605e4643d5a98fef14fd.tar.xz
linux-35cd78156c499ef83f60605e4643d5a98fef14fd.zip
vmscan: throttle direct reclaim when too many pages are isolated already
When way too many processes go into direct reclaim, it is possible for all of the pages to be taken off the LRU. One result of this is that the next process in the page reclaim code thinks there are no reclaimable pages left and triggers an out of memory kill. One solution to this problem is to never let so many processes into the page reclaim path that the entire LRU is emptied. Limiting the system to only having half of each inactive list isolated for reclaim should be safe. Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/vmscan.c33
1 files changed, 33 insertions, 0 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 75c29974e878..f90b76086ffa 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1034,6 +1034,31 @@ int isolate_lru_page(struct page *page)
}
/*
+ * Are there way too many processes in the direct reclaim path already?
+ */
+static int too_many_isolated(struct zone *zone, int file,
+ struct scan_control *sc)
+{
+ unsigned long inactive, isolated;
+
+ if (current_is_kswapd())
+ return 0;
+
+ if (!scanning_global_lru(sc))
+ return 0;
+
+ if (file) {
+ inactive = zone_page_state(zone, NR_INACTIVE_FILE);
+ isolated = zone_page_state(zone, NR_ISOLATED_FILE);
+ } else {
+ inactive = zone_page_state(zone, NR_INACTIVE_ANON);
+ isolated = zone_page_state(zone, NR_ISOLATED_ANON);
+ }
+
+ return isolated > inactive;
+}
+
+/*
* shrink_inactive_list() is a helper for shrink_zone(). It returns the number
* of reclaimed pages
*/
@@ -1048,6 +1073,14 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
int lumpy_reclaim = 0;
+ while (unlikely(too_many_isolated(zone, file, sc))) {
+ congestion_wait(WRITE, HZ/10);
+
+ /* We are about to die and free our memory. Return now. */
+ if (fatal_signal_pending(current))
+ return SWAP_CLUSTER_MAX;
+ }
+
/*
* If we need a large contiguous chunk of memory, or have
* trouble getting a small set of contiguous pages, we