Re: 2.4.20: Proccess stuck in __lock_page ...

[Andrew Morton]

Matthias Mueller <[e-mail]> wrote:
>
> Works fine on my notebook. Good throughput and no mouse hangs anymore.

Interesting.

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]);
 	}
 }

_