Re: 2.4.20: Proccess stuck in __lock_page ...

[Matthias Mueller (matthias.mueller@rz.uni-karlsruhe.de)]

On Wed, May 28, 2003 at 03:23:15AM -0700, Andrew Morton wrote:
> Could you please work out which change caused it?  Go back to stock 2.4 and
> then apply this:
> 
> 
> diff -puN drivers/block/ll_rw_blk.c~1 drivers/block/ll_rw_blk.c
> --- 24/drivers/block/ll_rw_blk.c~1	2003-05-28 03:20:42.000000000 -0700
> +++ 24-akpm/drivers/block/ll_rw_blk.c	2003-05-28 03:20:57.000000000 -0700
> @@ -590,10 +590,10 @@ static struct request *__get_request_wai
>  	register struct request *rq;
>  	DECLARE_WAITQUEUE(wait, current);
>  
> -	generic_unplug_device(q);
>  	add_wait_queue_exclusive(&q->wait_for_requests[rw], &wait);
>  	do {
>  		set_current_state(TASK_UNINTERRUPTIBLE);
> +		generic_unplug_device(q);
>  		if (q->rq[rw].count == 0)
>  			schedule();
>  		spin_lock_irq(&io_request_lock);
> 
> 
> 
> then this:
> 
> diff -puN drivers/block/ll_rw_blk.c~2 drivers/block/ll_rw_blk.c
> --- 24/drivers/block/ll_rw_blk.c~2	2003-05-28 03:21:03.000000000 -0700
> +++ 24-akpm/drivers/block/ll_rw_blk.c	2003-05-28 03:21:09.000000000 -0700
> @@ -590,7 +590,7 @@ static struct request *__get_request_wai
>  	register struct request *rq;
>  	DECLARE_WAITQUEUE(wait, current);
>  
> -	add_wait_queue_exclusive(&q->wait_for_requests[rw], &wait);
> +	add_wait_queue(&q->wait_for_requests[rw], &wait);
>  	do {
>  		set_current_state(TASK_UNINTERRUPTIBLE);
>  		generic_unplug_device(q);
> 
> 
> Then this (totally unlikely, don't bother):
> 
> diff -puN drivers/block/ll_rw_blk.c~3 drivers/block/ll_rw_blk.c
> --- 24/drivers/block/ll_rw_blk.c~3	2003-05-28 03:21:15.000000000 -0700
> +++ 24-akpm/drivers/block/ll_rw_blk.c	2003-05-28 03:21:39.000000000 -0700
> @@ -829,8 +829,7 @@ void blkdev_release_request(struct reque
>  	 */
>  	if (q) {
>  		list_add(&req->queue, &q->rq[rw].free);
> -		if (++q->rq[rw].count >= q->batch_requests &&
> -				waitqueue_active(&q->wait_for_requests[rw]))
> +		if (++q->rq[rw].count >= q->batch_requests)
>  			wake_up(&q->wait_for_requests[rw]);
>  	}
>  }
> 
> _

Tested all of them and some combinations:
patch 1 alone: still mouse hangs
patch 2 alone: still mouse hangs
patch 3 alone: no hangs, but I get some zombie process (starting a lot of
               xterms results in zombie xterms, not noticed with vanilla
               and the other patches)
patch 1+2: no mouse hangs
patch 1+2+3: no mouse hangs, no zombies

Bye,
Matthias
-- 
Matthias.Mueller@xxxxxxxxxxxxxxxxxxx
Rechenzentrum Universitaet Karlsruhe
Abteilung Netze
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