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authorMel Gorman <mgorman@suse.de>2011-04-25 21:36:42 +0000
committerMarek Szyprowski <m.szyprowski@samsung.com>2012-05-21 15:09:34 +0200
commitcfd3da1e49bb95c355c01c0f502d657deb3d34a4 (patch)
tree002aa5a9001a7b600ea8af90b59ccbbe133d48e0 /mm
parent0815f3d81d76dfbf2abcfd93a85ff0a6008fe4c0 (diff)
downloadlinux-cfd3da1e49bb95c355c01c0f502d657deb3d34a4.tar.bz2
mm: Serialize access to min_free_kbytes
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@chello.nl: Older patch fixed the race with spinlock] Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Tested-by: Barry Song <Baohua.Song@csr.com>
Diffstat (limited to 'mm')
-rw-r--r--mm/page_alloc.c23
1 files changed, 15 insertions, 8 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 116c087f76bb..8be37bcda0b2 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5020,14 +5020,7 @@ 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 lowmem_pages = 0;
@@ -5082,6 +5075,20 @@ 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