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authorMinchan Kim <minchan@kernel.org>2012-10-08 16:33:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-09 16:22:59 +0900
commit5a883813845a2bb5ed2bd8c9240736c0740b156f (patch)
tree86d5b34fb76870923d0c2b4b5ebd72972b15b654 /mm
parent082708072a4250f5c4dbc62065e7af93f5e45646 (diff)
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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.c7
-rw-r--r--mm/vmstat.c12
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