Re: D state after applying ps hang patch

[Jens Axboe <axboe@suse.de>]

On Sun, Jan 28 2001, David Ford wrote:
> The one LInus posted plus his addendum for the ll_rw_blk.
> http://blue-labs.org/patches/ps-hang.patch

You merged it wrong, Linus suggested to remove the entire

		if (!list_empty(&q->request_freelist[rw])) {
			blk_refill_freelist(q, rw);
			list_add(&req->table, &q->request_freelist[rw]);
			return;
		}

In fact, with the change you made the box can't possible survive
for very long - once the queue freelists are empty, you will
deadlock immediately.

Try this ll_rw_blk.c change instead, on top of pre11. Include
Linus' mm fixes of course.

--- /opt/kernel/linux-2.4.1-pre10/drivers/block/ll_rw_blk.c	Thu Jan 25 19:15:12 2001
+++ drivers/block/ll_rw_blk.c	Sun Jan 28 19:22:20 2001
@@ -633,6 +634,8 @@
 		if (!list_empty(&q->request_freelist[rw])) {
 			blk_refill_freelist(q, rw);
 			list_add(&req->table, &q->request_freelist[rw]);
+			if (waitqueue_active(&q->wait_for_request))
+				wake_up_nr(&q->wait_for_request, 2);
 			return;
 		}
 

-- 
Jens Axboe

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