Messages in this thread Patch in this message | | | Date | Wed, 28 May 2003 12:50:29 +0200 | From | Jens Axboe <> | Subject | Re: 2.4.20: Proccess stuck in __lock_page ... |
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On Wed, May 28 2003, Con Kolivas wrote: > On Wed, 28 May 2003 20:25, Jens Axboe wrote: > > On Wed, May 28 2003, Andrew Morton wrote: > > > Matthias Mueller <matthias.mueller@rz.uni-karlsruhe.de> 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); > > > > I think it was already established that this wasn't the reason. Was my > > first suspect too, though... > > > > > 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); > > > > Since we do a general wake_up(), only the order of wakeups matter here > > right (lifo vs fifo). Given that, the _exclusive() should be more fair > > possibly at the cost of a bit of throughput. > > > > > 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]); > > > } > > > } > > > > Well it's the only one left :). But you are right, try one of them at > > the time, establishing the effect of each of them. > > THIS IS IT! The last one. No pauses writing a 2Gb file now unless I do a read > midstream.
Cool, especially since we can easily apply this to -rc5 without any worries. Marcelo, if you please...?
===== drivers/block/ll_rw_blk.c 1.44 vs edited ===== --- 1.44/drivers/block/ll_rw_blk.c Mon Apr 14 12:53:03 2003 +++ edited/drivers/block/ll_rw_blk.c Wed May 28 12:49:30 2003 @@ -829,8 +829,7 @@ */ 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]); } } -- Jens Axboe
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