From: Christoph Hellwig <hch@infradead.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: Shaohua Li <shli@kernel.org>, Dave Chinner <david@fromorbit.com>,
linux-kernel@vger.kernel.org
Subject: Re: [Regression x2, 3.13-git] virtio block mq hang, iostat busted on virtio devices
Date: Wed, 20 Nov 2013 00:07:02 -0800 [thread overview]
Message-ID: <20131120080702.GB13147@infradead.org> (raw)
In-Reply-To: <20131120015426.GE4094@kernel.dk>
> Just stumbled on that too. You need one more, btw, for the sg failure
> case:
>
>
> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> index 588479d58f52..6a680d4de7f1 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -199,15 +199,16 @@ static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req)
>
> spin_lock_irqsave(&vblk->vq_lock, flags);
> if (__virtblk_add_req(vblk->vq, vbr, vbr->sg, num) < 0) {
> + virtqueue_kick(vblk->vq);
> spin_unlock_irqrestore(&vblk->vq_lock, flags);
> blk_mq_stop_hw_queue(hctx);
> - virtqueue_kick(vblk->vq);
> return BLK_MQ_RQ_QUEUE_BUSY;
> }
> - spin_unlock_irqrestore(&vblk->vq_lock, flags);
>
> if (last)
> virtqueue_kick(vblk->vq);
> +
> + spin_unlock_irqrestore(&vblk->vq_lock, flags);
Note that virtqueue_kick can be split into a virtqueue_prepare_split
that needs the lock, and a virtqueue_notify that doesn't, but it might
not be nessecary to do that optimization right now.
Btw, how much do I need to bribe you to send mails where I don't have
step over 500 lines of dead quotes to find the actual patch?
next prev parent reply other threads:[~2013-11-20 8:07 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-19 8:02 [Regression x2, 3.13-git] virtio block mq hang, iostat busted on virtio devices Dave Chinner
2013-11-19 10:36 ` Christoph Hellwig
2013-11-19 16:05 ` Jens Axboe
2013-11-19 16:09 ` Christoph Hellwig
2013-11-19 16:16 ` Jens Axboe
2013-11-19 21:30 ` Dave Chinner
2013-11-19 21:40 ` Jens Axboe
2013-11-19 20:15 ` Jens Axboe
2013-11-19 21:20 ` Jens Axboe
2013-11-19 21:34 ` Dave Chinner
2013-11-19 21:43 ` Jens Axboe
2013-11-19 22:42 ` Jens Axboe
2013-11-19 22:51 ` Jens Axboe
2013-11-19 23:23 ` Dave Chinner
2013-11-19 23:59 ` Jens Axboe
2013-11-20 0:08 ` Jens Axboe
2013-11-20 1:44 ` Shaohua Li
2013-11-20 1:54 ` Jens Axboe
2013-11-20 2:02 ` Jens Axboe
2013-11-20 2:53 ` Dave Chinner
2013-11-20 3:12 ` Jens Axboe
2013-11-20 8:07 ` Christoph Hellwig [this message]
2013-11-20 16:21 ` Jens Axboe
2013-11-20 8:04 ` Christoph Hellwig
2013-11-20 16:20 ` Jens Axboe
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