Re: [PATCH] Make treercu safe for suspend and resume

[Ingo Molnar <mingo@elte.hu>]

* Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:

> Hello!
> 
> Kudos to both Dhaval Giani and Jens Axboe for finding a bug in treercu
> that causes warnings after suspend-resume cycles in Dhaval's case and
> during stress tests in Jens's case.  It would also probably cause failures
> if heavily stressed.  The solution, ironically enough, is to revert to
> rcupreempt's code for initializing the dynticks state.  And the patch
> even results in smaller code -- so what was I thinking???
> 
> This is 2.6.29 material, given that people really do suspend and resume
> Linux these days.  ;-)
> 
> Located-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
> Located-by: Jens Axboe <jens.axboe@oracle.com>
> Tested-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
> Tested-by: Jens Axboe <jens.axboe@oracle.com>
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> ---
> 
>  rcutree.c |   12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)

applied to tip/core/urgent, thanks guys!

	Ingo