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| author | Minchan Kim <minchan@kernel.org> | 2012-10-08 16:33:39 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-09 16:22:59 +0900 |
| commit | 5a883813845a2bb5ed2bd8c9240736c0740b156f (patch) | |
| tree | 86d5b34fb76870923d0c2b4b5ebd72972b15b654 /mm | |
| parent | 082708072a4250f5c4dbc62065e7af93f5e45646 (diff) | |
| download | lwn-5a883813845a2bb5ed2bd8c9240736c0740b156f.tar.gz lwn-5a883813845a2bb5ed2bd8c9240736c0740b156f.zip | |
memory-hotplug: fix zone stat mismatch
During memory-hotplug, I found NR_ISOLATED_[ANON|FILE] are increasing,
causing the kernel to hang. When the system doesn't have enough free
pages, it enters reclaim but never reclaim any pages due to
too_many_isolated()==true and loops forever.
The cause is that when we do memory-hotadd after memory-remove,
__zone_pcp_update() clears a zone's ZONE_STAT_ITEMS in setup_pageset()
although the vm_stat_diff of all CPUs still have values.
In addtion, when we offline all pages of the zone, we reset them in
zone_pcp_reset without draining so we loss some zone stat item.
Reviewed-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/page_alloc.c | 7 | ||||
| -rw-r--r-- | mm/vmstat.c | 12 |
2 files changed, 19 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 9b8e6243a524..5485f0ef4ec3 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5916,6 +5916,7 @@ static int __meminit __zone_pcp_update(void *data) local_irq_save(flags); if (pcp->count > 0) free_pcppages_bulk(zone, pcp->count, pcp); + drain_zonestat(zone, pset); setup_pageset(pset, batch); local_irq_restore(flags); } @@ -5932,10 +5933,16 @@ void __meminit zone_pcp_update(struct zone *zone) void zone_pcp_reset(struct zone *zone) { unsigned long flags; + int cpu; + struct per_cpu_pageset *pset; /* avoid races with drain_pages() */ local_irq_save(flags); if (zone->pageset != &boot_pageset) { + for_each_online_cpu(cpu) { + pset = per_cpu_ptr(zone->pageset, cpu); + drain_zonestat(zone, pset); + } free_percpu(zone->pageset); zone->pageset = &boot_pageset; } diff --git a/mm/vmstat.c b/mm/vmstat.c index 05e3a9913744..2f11309955cc 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -495,6 +495,18 @@ void refresh_cpu_vm_stats(int cpu) atomic_long_add(global_diff[i], &vm_stat[i]); } +void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset) +{ + int i; + + for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) + if (pset->vm_stat_diff[i]) { + int v = pset->vm_stat_diff[i]; + pset->vm_stat_diff[i] = 0; + atomic_long_add(v, &zone->vm_stat[i]); + atomic_long_add(v, &vm_stat[i]); + } +} #endif #ifdef CONFIG_NUMA |