[PATCH] mm, vmscan: throttle too_many_isolated by uninterruptible sleep

[Michal Hocko]

"mm, vmscan: do not loop on too_many_isolated for ever" has added an
interruptible sleep into shrink_inactive_list when we have isolated too
many pages. Andrew has noticed that we used to sleep in uninterruptible
sleep previously (in congestion_wait) and that changing that is wrong
for at least two reasons
	- waiting task would not participate in the load average anymore
	- task with a pending signal will not sleep and bail out
	  immediately
While none of those issues are critical in any way but they are
unnecessary. The interruptible sleep was more an oversight than a
deliberate decision. Fix this by using msleep instead.

Spotted-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
---
 mm/vmscan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 7ba9467b6d58..ed0c29a3db16 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1749,7 +1749,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
 			return 0;
 
 		/* wait a bit for the reclaimer. */
-		schedule_timeout_interruptible(HZ/10);
+		msleep(100);
 		stalled = true;
 
 		/* We are about to die and free our memory. Return now. */
-- 
2.13.2


-- 
Michal Hocko
SUSE Labs