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-rw-r--r--mm/page_alloc.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d4bcc20ab6f0..8d4335779633 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -65,6 +65,9 @@
#include <asm/div64.h>
#include "internal.h"
+/* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
+static DEFINE_MUTEX(pcp_batch_high_lock);
+
#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
DEFINE_PER_CPU(int, numa_node);
EXPORT_PER_CPU_SYMBOL(numa_node);
@@ -5557,6 +5560,8 @@ int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
if (!write || (ret < 0))
return ret;
+
+ mutex_lock(&pcp_batch_high_lock);
for_each_populated_zone(zone) {
for_each_possible_cpu(cpu) {
unsigned long high;
@@ -5565,6 +5570,7 @@ int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
per_cpu_ptr(zone->pageset, cpu), high);
}
}
+ mutex_unlock(&pcp_batch_high_lock);
return 0;
}
@@ -6078,7 +6084,9 @@ static int __meminit __zone_pcp_update(void *data)
void __meminit zone_pcp_update(struct zone *zone)
{
+ mutex_lock(&pcp_batch_high_lock);
stop_machine(__zone_pcp_update, zone, NULL);
+ mutex_unlock(&pcp_batch_high_lock);
}
#endif