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authorMinchan Kim <minchan.kim@gmail.com>2010-09-22 16:05:01 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2010-09-22 20:22:39 -0400
commitd1908362ae0b97374eb8328fbb471576332f9fb1 (patch)
treedb8ba2a4de2e9ac61b8e94fc03a76ddbd24d321f
parenteba93fcc34d6c4387ce8fbb53bb7b685f91f3343 (diff)
vmscan: check all_unreclaimable in direct reclaim path
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 <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 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 <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Reported-by: M. Vefa Bicakci <bicave@superonline.com> Reported-by: <caiqian@redhat.com> Reviewed-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: <caiqian@redhat.com> Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/vmscan.c43
1 files changed, 35 insertions, 8 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index c391c320dba..c5dfabf25f1 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1804,12 +1804,11 @@ static void shrink_zone(int priority, struct zone *zone,
1804 * If a zone is deemed to be full of pinned pages then just give it a light 1804 * If a zone is deemed to be full of pinned pages then just give it a light
1805 * scan then give up on it. 1805 * scan then give up on it.
1806 */ 1806 */
1807static bool shrink_zones(int priority, struct zonelist *zonelist, 1807static void shrink_zones(int priority, struct zonelist *zonelist,
1808 struct scan_control *sc) 1808 struct scan_control *sc)
1809{ 1809{
1810 struct zoneref *z; 1810 struct zoneref *z;
1811 struct zone *zone; 1811 struct zone *zone;
1812 bool all_unreclaimable = true;
1813 1812
1814 for_each_zone_zonelist_nodemask(zone, z, zonelist, 1813 for_each_zone_zonelist_nodemask(zone, z, zonelist,
1815 gfp_zone(sc->gfp_mask), sc->nodemask) { 1814 gfp_zone(sc->gfp_mask), sc->nodemask) {
@@ -1827,8 +1826,38 @@ static bool shrink_zones(int priority, struct zonelist *zonelist,
1827 } 1826 }
1828 1827
1829 shrink_zone(priority, zone, sc); 1828 shrink_zone(priority, zone, sc);
1830 all_unreclaimable = false;
1831 } 1829 }
1830}
1831
1832static bool zone_reclaimable(struct zone *zone)
1833{
1834 return zone->pages_scanned < zone_reclaimable_pages(zone) * 6;
1835}
1836
1837/*
1838 * As hibernation is going on, kswapd is freezed so that it can't mark
1839 * the zone into all_unreclaimable. It can't handle OOM during hibernation.
1840 * So let's check zone's unreclaimable in direct reclaim as well as kswapd.
1841 */
1842static bool all_unreclaimable(struct zonelist *zonelist,
1843 struct scan_control *sc)
1844{
1845 struct zoneref *z;
1846 struct zone *zone;
1847 bool all_unreclaimable = true;
1848
1849 for_each_zone_zonelist_nodemask(zone, z, zonelist,
1850 gfp_zone(sc->gfp_mask), sc->nodemask) {
1851 if (!populated_zone(zone))
1852 continue;
1853 if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
1854 continue;
1855 if (zone_reclaimable(zone)) {
1856 all_unreclaimable = false;
1857 break;
1858 }
1859 }
1860
1832 return all_unreclaimable; 1861 return all_unreclaimable;
1833} 1862}
1834 1863
@@ -1852,7 +1881,6 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
1852 struct scan_control *sc) 1881 struct scan_control *sc)
1853{ 1882{
1854 int priority; 1883 int priority;
1855 bool all_unreclaimable;
1856 unsigned long total_scanned = 0; 1884 unsigned long total_scanned = 0;
1857 struct reclaim_state *reclaim_state = current->reclaim_state; 1885 struct reclaim_state *reclaim_state = current->reclaim_state;
1858 struct zoneref *z; 1886 struct zoneref *z;
@@ -1869,7 +1897,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
1869 sc->nr_scanned = 0; 1897 sc->nr_scanned = 0;
1870 if (!priority) 1898 if (!priority)
1871 disable_swap_token(); 1899 disable_swap_token();
1872 all_unreclaimable = shrink_zones(priority, zonelist, sc); 1900 shrink_zones(priority, zonelist, sc);
1873 /* 1901 /*
1874 * Don't shrink slabs when reclaiming memory from 1902 * Don't shrink slabs when reclaiming memory from
1875 * over limit cgroups 1903 * over limit cgroups
@@ -1931,7 +1959,7 @@ out:
1931 return sc->nr_reclaimed; 1959 return sc->nr_reclaimed;
1932 1960
1933 /* top priority shrink_zones still had more to do? don't OOM, then */ 1961 /* top priority shrink_zones still had more to do? don't OOM, then */
1934 if (scanning_global_lru(sc) && !all_unreclaimable) 1962 if (scanning_global_lru(sc) && !all_unreclaimable(zonelist, sc))
1935 return 1; 1963 return 1;
1936 1964
1937 return 0; 1965 return 0;
@@ -2197,8 +2225,7 @@ loop_again:
2197 total_scanned += sc.nr_scanned; 2225 total_scanned += sc.nr_scanned;
2198 if (zone->all_unreclaimable) 2226 if (zone->all_unreclaimable)
2199 continue; 2227 continue;
2200 if (nr_slab == 0 && 2228 if (nr_slab == 0 && !zone_reclaimable(zone))
2201 zone->pages_scanned >= (zone_reclaimable_pages(zone) * 6))
2202 zone->all_unreclaimable = 1; 2229 zone->all_unreclaimable = 1;
2203 /* 2230 /*
2204 * If we've done a decent amount of scanning and 2231 * If we've done a decent amount of scanning and