Re: CFS and suspend2: hang in atomic copy

["Bob Picco" <bob.picco@hp.com>]

Ingo Molnar wrote:	[Thu Apr 19 2007, 02:29:36AM EDT]
> 
> * Bob Picco <bob.picco@hp.com> wrote:
> 
> > I had hoped to collect more data with CFS V2. It crashes in 
> > scale_nice_down for s2ram when attempting to disable_nonboot_cpus. So 
> > part of traceback looks like (typed by hand with obvious omissions):
> > 
> > scale_nice_down
> > update_stats_wait_end - not shown in traceback because inlined
> > pick_next_task_fair
> > migration_call
> > task_rq_lock
> > notifier_call_chain
> > _cpu_down
> > disable_nonboot_cpus
> 
> ok, this looks similar to the jpeg Christian did. Does the patch below 
> fix the crash for you?
> 
> 	Ingo
> 
> ---
>  kernel/sched.c |    2 ++
>  1 file changed, 2 insertions(+)
> 
> Index: linux/kernel/sched.c
> ===================================================================
> --- linux.orig/kernel/sched.c
> +++ linux/kernel/sched.c
> @@ -4425,6 +4425,8 @@ static void migrate_dead_tasks(unsigned 
>  	struct task_struct *next;
>  
>  	for (;;) {
> +		if (!rq->nr_running)
> +			break;
>  		next = pick_next_task(rq, rq->curr);
>  		if (!next)
>  			break;
This patch repairs s2ram issue. 

Thanks.

bob