From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id EDD4A6B007B for ; Sat, 18 Sep 2010 08:52:45 -0400 (EDT) Date: Sat, 18 Sep 2010 08:52:34 -0400 (EDT) From: caiqian@redhat.com Message-ID: <290491919.1298351284814354705.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com> In-Reply-To: <1296415999.1298271284814035815.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com> Subject: cgroup oom regression introduced by 6a5ce1b94e1e5979f8db579f77d6e08a5f44c13b MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Minchan Kim Cc: linux-mm , KOSAKI Motohiro , "M. Vefa Bicakci" , Johannes Weiner , Rik van Riel , stable@kernel.org, akpm@linux-foundation.org List-ID: This test hung the kernel without triggering oom. # mount -t cgroup -o memory none /cgroup/memory/ # mkdir /cgroup/memory/A # echo $$ >/cgroup/memory/A/tasks # echo 4096M >/cgroup/memory/A/memory.limit_in_bytes # echo 4096M >/cgroup/memory/A/memory.memsw.limit_in_bytes # use malloc to allocate more than 4G memory. Sometimes, this had been thrown out of console, localhost.localdomain login: INFO: task sm1:5065 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. sm1 D 00000000fffca130 0 5065 5051 0x00000080 ffff880c5f419c38 0000000000000086 ffff880c5f419bc8 ffffffff81034ca8 ffff880100000000 0000000000015440 ffff880c608ab4e0 0000000000015440 ffff880c608aba40 ffff880c5f419fd8 ffff880c608aba48 ffff880c5f419fd8 Call Trace: [] ? pvclock_clocksource_read+0x58/0xd0 [] ? sync_page+0x0/0x50 [] io_schedule+0x73/0xc0 [] sync_page+0x3d/0x50 [] __wait_on_bit_lock+0x5a/0xc0 [] __lock_page+0x67/0x70 [] ? wake_bit_function+0x0/0x50 [] ? find_get_page+0x1e/0xa0 [] filemap_fault+0x33c/0x450 [] __do_fault+0x54/0x550 [] ? __mem_cgroup_commit_charge+0x5a/0xa0 [] handle_mm_fault+0x1c2/0xc70 [] do_page_fault+0x11c/0x320 [] page_fault+0x25/0x30 Reverted the following commit from mmotm tree made the problem go away. commit 6a5ce1b94e1e5979f8db579f77d6e08a5f44c13b Author: Minchan Kim Date: Thu Sep 16 01:17:26 2010 +0200 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 bisected the regression to commit bb21c7ce18eff8e6e7877ca1d06c6db719376e3c Author: KOSAKI Motohiro 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 that vmscan don't care enough OOM case when oom_killer_disabled. The problem sequence is following as. 1. hibernation 2. oom_disable 3. alloc_pages 4. do_try_to_free_pages if (scanning_global_lru(sc) && !all_unreclaimable) return 1; If kswapd is not freozen, it would set zone->all_unreclaimable to 1 and then shrink_zones maybe return true(ie, all_unreclaimable is true). So at last, alloc_pages could go to _nopage_. If it is, it should have no problem. This patch adds all_unreclaimable check to protect in direct reclaim path, too. It can care of hibernation OOM case and help bailout all_unreclaimable case slightly. Signed-off-by: KOSAKI Motohiro Signed-off-by: Minchan Kim Reported-by: M. Vefa Bicakci Acked-by: Rafael J. Wysocki Reviewed-by: Johannes Weiner Cc: Rik van Riel Cc: Signed-off-by: Andrew Morton diff --git a/mm/vmscan.c b/mm/vmscan.c index 225a759..f56a8c3 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1804,12 +1804,11 @@ 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) { @@ -1827,8 +1826,36 @@ static bool shrink_zones(int priority, struct zonelist *zonelist, } shrink_zone(priority, zone, sc); - all_unreclaimable = false; } +} + +static inline bool zone_reclaimable(struct zone *zone) +{ + return zone->pages_scanned < zone_reclaimable_pages(zone) * 6; +} + +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_reclaimable(zone)) { + all_unreclaimable = false; + break; + } + } + return all_unreclaimable; } @@ -1852,7 +1879,6 @@ 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; @@ -1869,7 +1895,7 @@ 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 @@ -1931,7 +1957,7 @@ 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; @@ -2197,8 +2223,7 @@ loop_again: total_scanned += sc.nr_scanned; if (zone->all_unreclaimable) continue; - if (nr_slab == 0 && - zone->pages_scanned >= (zone_reclaimable_pages(zone) * 6)) + if (nr_slab == 0 && !zone_reclaimable(zone)) zone->all_unreclaimable = 1; /* * If we've done a decent amount of scanning and -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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