diff options
author | KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> | 2010-06-04 14:15:05 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-06-04 15:21:45 -0700 |
commit | bb21c7ce18eff8e6e7877ca1d06c6db719376e3c (patch) | |
tree | 555edaded1e0a771df406ce2b6b63368df6de6cd | |
parent | 9e506f7adce8e6165a104d3d78fddd8ff0cdccf8 (diff) | |
download | linux-3.10-bb21c7ce18eff8e6e7877ca1d06c6db719376e3c.tar.gz linux-3.10-bb21c7ce18eff8e6e7877ca1d06c6db719376e3c.tar.bz2 linux-3.10-bb21c7ce18eff8e6e7877ca1d06c6db719376e3c.zip |
vmscan: fix do_try_to_free_pages() return value when priority==0 reclaim failure
Greg Thelen reported recent Johannes's stack diet patch makes kernel hang.
His test is following.
mount -t cgroup none /cgroups -o memory
mkdir /cgroups/cg1
echo $$ > /cgroups/cg1/tasks
dd bs=1024 count=1024 if=/dev/null of=/data/foo
echo $$ > /cgroups/tasks
echo 1 > /cgroups/cg1/memory.force_empty
Actually, This OOM hard to try logic have been corrupted since following
two years old patch.
commit a41f24ea9fd6169b147c53c2392e2887cc1d9247
Author: Nishanth Aravamudan <nacc@us.ibm.com>
Date: Tue Apr 29 00:58:25 2008 -0700
page allocator: smarter retry of costly-order allocations
Original intention was "return success if the system have shrinkable zones
though priority==0 reclaim was failure". But the above patch changed to
"return nr_reclaimed if .....". Oh, That forgot nr_reclaimed may be 0 if
priority==0 reclaim failure.
And Johannes's patch 0aeb2339e54e ("vmscan: remove all_unreclaimable scan
control") made it more corrupt. Originally, priority==0 reclaim failure
on memcg return 0, but this patch changed to return 1. It totally
confused memcg.
This patch fixes it completely.
Reported-by: Greg Thelen <gthelen@google.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Greg Thelen <gthelen@google.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | mm/vmscan.c | 29 |
1 files changed, 16 insertions, 13 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 915dceb487c..9c7e57cc63a 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1724,13 +1724,13 @@ static void shrink_zone(int priority, struct zone *zone, * If a zone is deemed to be full of pinned pages then just give it a light * scan then give up on it. */ -static int shrink_zones(int priority, struct zonelist *zonelist, +static bool shrink_zones(int priority, struct zonelist *zonelist, struct scan_control *sc) { enum zone_type high_zoneidx = gfp_zone(sc->gfp_mask); struct zoneref *z; struct zone *zone; - int progress = 0; + bool all_unreclaimable = true; for_each_zone_zonelist_nodemask(zone, z, zonelist, high_zoneidx, sc->nodemask) { @@ -1757,9 +1757,9 @@ static int shrink_zones(int priority, struct zonelist *zonelist, } shrink_zone(priority, zone, sc); - progress = 1; + all_unreclaimable = false; } - return progress; + return all_unreclaimable; } /* @@ -1782,7 +1782,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, struct scan_control *sc) { int priority; - unsigned long ret = 0; + bool all_unreclaimable; unsigned long total_scanned = 0; struct reclaim_state *reclaim_state = current->reclaim_state; unsigned long lru_pages = 0; @@ -1813,7 +1813,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, sc->nr_scanned = 0; if (!priority) disable_swap_token(); - ret = shrink_zones(priority, zonelist, sc); + all_unreclaimable = shrink_zones(priority, zonelist, sc); /* * Don't shrink slabs when reclaiming memory from * over limit cgroups @@ -1826,10 +1826,8 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, } } total_scanned += sc->nr_scanned; - if (sc->nr_reclaimed >= sc->nr_to_reclaim) { - ret = sc->nr_reclaimed; + if (sc->nr_reclaimed >= sc->nr_to_reclaim) goto out; - } /* * Try to write back as many pages as we just scanned. This @@ -1849,9 +1847,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, priority < DEF_PRIORITY - 2) congestion_wait(BLK_RW_ASYNC, HZ/10); } - /* top priority shrink_zones still had more to do? don't OOM, then */ - if (ret && scanning_global_lru(sc)) - ret = sc->nr_reclaimed; + out: /* * Now that we've scanned all the zones at this priority level, note @@ -1877,7 +1873,14 @@ out: delayacct_freepages_end(); put_mems_allowed(); - return ret; + if (sc->nr_reclaimed) + return sc->nr_reclaimed; + + /* top priority shrink_zones still had more to do? don't OOM, then */ + if (scanning_global_lru(sc) && !all_unreclaimable) + return 1; + + return 0; } unsigned long try_to_free_pages(struct zonelist *zonelist, int order, |