Re: [PATCH 0/2] blk-throttle: Couple of more fixes

[Vivek Goyal <vgoyal@redhat.com>]

On Wed, Dec 15, 2010 at 04:07:33PM -0500, Vivek Goyal wrote:
> Hi Jens,
> 
> Please find attached couple of more fixes for blk-throttle code. These are
> based on top of "for-linus" branch of your block tree. 
> 

Hi Jens,

Do you have any concerns with these two fixes? Now Oleg and Paul have
acked it too. Could you please apply these for 2.6.38.

Thanks
Vivek

> Oleg had pointed out couple of race conditions in cgroup weight update code.
> I think these race conditions are hard to hit and not disastrous so I would
> not be too concerned about pushing these patches in 2.6.37 and can queue
> up for 2.6.38.
> 
> Paul,
> 
> Based on discussion in other mail thread, I have used xchg() based
> implementation for updating and processing limtis.  Can you please have a look
> if it is correct implementation and do I need any ACCESS_ONCE() or barriers
> somewhere. If this implementation is not correct then I can go back to atomic
> variable based implementation as suggested by you in other mail thread.
> Appreciate the help.
> 
> Thanks
> Vivek
> 
> Vivek Goyal (2):
>   blk-throttle: process limit change only through one function
>   blk-throttle: Some cleanups and race fixes in limit update code
> 
>  block/blk-throttle.c |  104 ++++++++++++++++++++------------------------------
>  1 files changed, 41 insertions(+), 63 deletions(-)