Messages in this thread Patch in this message | | | From | Minchan Kim <> | Subject | [PATCH] vmscan: don't use return value trick when oom_killer_disabled | Date | Fri, 3 Sep 2010 00:47:41 +0900 |
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M. Vefa Bicakci reported 2.6.35 kernel hang up when hibernation on his 32bit 3GB mem machine. (https://bugzilla.kernel.org/show_bug.cgi?id=16771) Also he was bisected first bad commit is below
commit bb21c7ce18eff8e6e7877ca1d06c6db719376e3c Author: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Date: Fri Jun 4 14:15:05 2010 -0700
vmscan: fix do_try_to_free_pages() return value when priority==0 reclaim failure
At first impression, this seemed very strange because the above commit only chenged function return value and hibernate_preallocate_memory() ignore return value of shrink_all_memory(). But it's related.
Now, page allocation from hibernation code may enter infinite loop if the system has highmem.
The reasons are two. 1) hibernate_preallocate_memory() call alloc_pages() wrong order 2) vmscan don't care enough OOM case when oom_killer_disabled.
This patch only fix (2). Why is oom_killer_disabled so special? because when hibernation case, zone->all_unreclaimable never be turned on. hibernation freeze all tasks at first, then kswapd can't works in this case, and zone->all_unreclaimable is only turned from kswapd.
Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: M. Vefa Bicakci <bicave@superonline.com> Cc: stable@kernel.org Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Minchan Kim <minchan.kim@gmail.com> --- mm/vmscan.c | 33 +++++++++++++++++++++++++++------ 1 files changed, 27 insertions(+), 6 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c index f620ab3..53b23a7 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1893,12 +1893,11 @@ 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 bool shrink_zones(int priority, struct zonelist *zonelist, +static void shrink_zones(int priority, struct zonelist *zonelist, struct scan_control *sc) { struct zoneref *z; struct zone *zone; - bool all_unreclaimable = true; for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(sc->gfp_mask), sc->nodemask) { @@ -1916,8 +1915,31 @@ static bool shrink_zones(int priority, struct zonelist *zonelist, } shrink_zone(priority, zone, sc); - all_unreclaimable = false; } +} + +static inline bool all_unreclaimable(struct zonelist *zonelist, + struct scan_control *sc) +{ + struct zoneref *z; + struct zone *zone; + bool all_unreclaimable = true; + + if (!scanning_global_lru(sc)) + return false; + + for_each_zone_zonelist_nodemask(zone, z, zonelist, + gfp_zone(sc->gfp_mask), sc->nodemask) { + if (!populated_zone(zone)) + continue; + if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) + continue; + if (zone->pages_scanned < (zone_reclaimable_pages(zone) * 6)) { + all_unreclaimable = false; + break; + } + } + return all_unreclaimable; } @@ -1941,7 +1963,6 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, struct scan_control *sc) { int priority; - bool all_unreclaimable; unsigned long total_scanned = 0; struct reclaim_state *reclaim_state = current->reclaim_state; struct zoneref *z; @@ -1958,7 +1979,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, sc->nr_scanned = 0; if (!priority) disable_swap_token(); - all_unreclaimable = shrink_zones(priority, zonelist, sc); + shrink_zones(priority, zonelist, sc); /* * Don't shrink slabs when reclaiming memory from * over limit cgroups @@ -2020,7 +2041,7 @@ out: return sc->nr_reclaimed; /* top priority shrink_zones still had more to do? don't OOM, then */ - if (scanning_global_lru(sc) && !all_unreclaimable) + if (!all_unreclaimable(zonelist, sc)) return 1; return 0; -- 1.7.0.5
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