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

[Greg Kroah-Hartman]

On Sat, Jul 28, 2012 at 11:26:09AM +0100, Mel Gorman wrote:
> 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);
>  }

Added to the patch, thanks.

I think with this change, and the others requested, I'll do a -rc2 just
so that people can test it all again.

greg k-h
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