Re: SMP suspend broken due to "swsusp: Change code ordering in disk.c" et al.

[Johannes Berg <johannes@sipsolutions.net>]

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Hi,

> Could you please try the appended patch?  It's somewhat hackish, but may work.

Not before Monday or Tuesday unfortunately, I'm away from the machine.
Maybe I can find someone else willing to test who has the same box.

> The idea is to do nothing on CPU unplug if the CPU's worker thread is frozen
> and later check in the thread itself if it has been replaced by another one.

Yeah that should work. That patch won't apply to my tree though unless I
actually go to -mm2 as well :)

> Greetings,
> Rafael
> 
> 
>  kernel/workqueue.c |   10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> Index: linux-2.6.20-mm2/kernel/workqueue.c
> ===================================================================
> --- linux-2.6.20-mm2.orig/kernel/workqueue.c	2007-02-23 22:48:50.000000000 +0100
> +++ linux-2.6.20-mm2/kernel/workqueue.c	2007-02-24 00:58:57.000000000 +0100
> @@ -316,7 +316,13 @@ static int worker_thread(void *__cwq)
>  	do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0);
>  
>  	for (;;) {
> -		try_to_freeze();
> +		if (try_to_freeze()) {
> +			/* We've just exited the refrigerator.  If our CPU is
> +			 * a nonboot one, we might have been replaced.
> +			 */
> +			if (cwq->thread != current)
> +				break;
> +		}
>  
>  		prepare_to_wait(&cwq->more_work, &wait, TASK_INTERRUPTIBLE);
>  		if (!cwq->should_stop && list_empty(&cwq->worklist))
> @@ -713,7 +719,7 @@ static void cleanup_workqueue_thread(str
>  	int alive = 0;
>  
>  	spin_lock_irq(&cwq->lock);
> -	if (cwq->thread != NULL) {
> +	if (cwq->thread != NULL && !frozen(cwq->thread)) {
>  		insert_wq_barrier(cwq, &barr, 1);
>  		cwq->should_stop = 1;
>  		alive = 1;
> 

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