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make vmstat cpu-unplug safe

To: LKML <linux-kernel@...>, linux-mm <linux-mm@...>, Andrew Morton <akpm@...>, Christoph Lameter <clameter@...>
Cc: <kosaki.motohiro@...>
Date: Tuesday, May 6, 2008 - 3:02 am

btw: I think all_vm_event() author is Cristoph Lameter, right?


--------------------------------------------
When access cpu_online_map, We should prevent that dynamically 
change cpu_online_map by get_online_cpus().

Unfortunately, all_vm_events() doesn't it.

Signed-off-by: KOSAKI Motohiro &lt;kosaki.motohiro@jp.fujitsu.com&gt;
CC: Christoph Lameter &lt;clameter@sgi.com&gt;

---
 mm/vmstat.c |    2 ++
 1 file changed, 2 insertions(+)

Index: b/mm/vmstat.c
===================================================================
--- a/mm/vmstat.c       2008-05-04 23:00:52.000000000 +0900
+++ b/mm/vmstat.c       2008-05-06 16:13:32.000000000 +0900
@@ -42,7 +42,9 @@ static void sum_vm_events(unsigned long
 */
 void all_vm_events(unsigned long *ret)
 {
+       get_online_cpus();
        sum_vm_events(ret, &amp;cpu_online_map);
+       put_online_cpus();
 }
 EXPORT_SYMBOL_GPL(all_vm_events);



--
To: KOSAKI Motohiro <kosaki.motohiro@...>
Cc: LKML <linux-kernel@...>, linux-mm <linux-mm@...>, Andrew Morton <akpm@...>
Date: Tuesday, May 6, 2008 - 1:48 pm

Acked-by: Christoph Lameter &lt;clameter@sgi.com&gt;
--
speck-geostationary