Re: [ 39/40] cpuset: mm: reduce large amounts of memory barrierrelated damage v3

[Mel Gorman]

On Sat, Jul 28, 2012 at 02:02:31AM -0300, Herton Ronaldo Krzesinski wrote:
> > Thanks, I've merged this with the "original" in the tree, so all should
> > be good now.
> 
> Thanks. I saw what seems another issue now on the patch too, sorry for
> not noticing earlier: this backport is lacking the
> write_seqcount_{begin,end} on set_mems_allowed for the case with
> CONFIG_CPUSETS, like in the original patch:
> 

Not my finest moment :(

Thanks

---8<---
cpuset: mm: reduce large amounts of memory barrier related damage v3 fix

Missing hunk from backport.

Reported-by: Herton Ronaldo Krzesinski <herton.krzesinski@xxxxxxxxxxxxx>
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>

diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index 8f15695..7a7e5fd 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -113,7 +113,9 @@ static inline bool put_mems_allowed(unsigned int seq)
 static inline void set_mems_allowed(nodemask_t nodemask)
 {
 	task_lock(current);
+	write_seqcount_begin(&current->mems_allowed_seq);
 	current->mems_allowed = nodemask;
+	write_seqcount_end(&current->mems_allowed_seq);
 	task_unlock(current);
 }
 
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