[PATCH] mm: make shrink_all_memory try harder

Make shrink_all_memory() repeat the attempts to free more memory if there
seems to be no pages to free.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index f713e9f6ac73..548e023c193b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -33,6 +33,7 @@
 #include <linux/cpuset.h>
 #include <linux/notifier.h>
 #include <linux/rwsem.h>
+#include <linux/delay.h>
 
 #include <asm/tlbflush.h>
 #include <asm/div64.h>
@@ -1784,11 +1785,13 @@ unsigned long shrink_all_memory(unsigned long nr_pages)
         pg_data_t *pgdat;
         unsigned long nr_to_free = nr_pages;
         unsigned long ret = 0;
+        unsigned retry = 2;
         struct reclaim_state reclaim_state = {
                 .reclaimed_slab = 0,
         };
 
         current->reclaim_state = &reclaim_state;
+repeat:
         for_each_pgdat(pgdat) {
                 unsigned long freed;
 
@@ -1798,6 +1801,10 @@ unsigned long shrink_all_memory(unsigned long nr_pages)
                 if ((long)nr_to_free <= 0)
                         break;
         }
+        if (retry-- && ret < nr_pages) {
+                blk_congestion_wait(WRITE, HZ/5);
+                goto repeat;
+        }
         current->reclaim_state = NULL;
         return ret;
 }