[PATCHv23 10/16] mm: Serialize access to min_free_kbytes
Marek Szyprowski
m.szyprowski at samsung.com
Wed Feb 22 11:48:51 EST 2012
From: Mel Gorman <mgorman at suse.de>
There is a race between the min_free_kbytes sysctl, memory hotplug
and transparent hugepage support enablement. Memory hotplug uses a
zonelists_mutex to avoid a race when building zonelists. Reuse it to
serialise watermark updates.
[a.p.zijlstra at chello.nl: Older patch fixed the race with spinlock]
Signed-off-by: Mel Gorman <mgorman at suse.de>
Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
---
mm/page_alloc.c | 23 +++++++++++++++--------
1 files changed, 15 insertions(+), 8 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e590b95..0aa8079 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5027,14 +5027,7 @@ static void setup_per_zone_lowmem_reserve(void)
calculate_totalreserve_pages();
}
-/**
- * setup_per_zone_wmarks - called when min_free_kbytes changes
- * or when memory is hot-{added|removed}
- *
- * Ensures that the watermark[min,low,high] values for each zone are set
- * correctly with respect to min_free_kbytes.
- */
-void setup_per_zone_wmarks(void)
+static void __setup_per_zone_wmarks(void)
{
unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
unsigned long pages_low = extra_free_kbytes >> (PAGE_SHIFT - 10);
@@ -5095,6 +5088,20 @@ void setup_per_zone_wmarks(void)
calculate_totalreserve_pages();
}
+/**
+ * setup_per_zone_wmarks - called when min_free_kbytes changes
+ * or when memory is hot-{added|removed}
+ *
+ * Ensures that the watermark[min,low,high] values for each zone are set
+ * correctly with respect to min_free_kbytes.
+ */
+void setup_per_zone_wmarks(void)
+{
+ mutex_lock(&zonelists_mutex);
+ __setup_per_zone_wmarks();
+ mutex_unlock(&zonelists_mutex);
+}
+
/*
* The inactive anon list should be small enough that the VM never has to
* do too much work, but large enough that each inactive page has a chance
--
1.7.1.569.g6f426
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