On Thu, 2013-07-11 at 12:26 +0200, Alexander Gordeev wrote:
> On Wed, May 22, 2013 at 07:03:05PM +0200, Jens Axboe wrote:
> > On Wed, May 22 2013, Alexander Gordeev wrote:
> > > On Wed, May 22, 2013 at 08:50:03AM +0900, Tejun Heo wrote:
> > > > Hmmmmmm..... I'd normally apply this patch but block layer is just
> > > > growing multi-queue support and libata is likely to be converted to mq
> > > > in foreseeable future, so I'm a bit hesitant to make irq handling more
> > > > sophiscated right now. Would you be interested in looking into
> > > > converting libata to blk mq support? I'm pretty sure it'd yield far
> > > > better outcome if done properly.
> > >
> > > I am not committing, but will look into it, sure.
> >
> > Would be most awesome, I'm sure Nic would not mind a bit of help on the
> > SCSI/libata side :-)
>
> Hi Nicholas,
>
> Could you please clarify the status of SCSI MQ support? Is it usable now?
>
Hi Alexander,
Thanks for taking a look. I've not made further progress in the last
weeks on scsi-mq, but am still using virtio-scsi + scsi-mq <->
vhost-scsi + per-cpu-ida for quite a bit for benchmarking purposes.
> I tried git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending.git,
> but it does not appear working without (at least) changes below to SCSI lib:
>
The only scsi-mq LLD conversions so far have been to virtio-scsi +
scsi_debug to nop REQ_TYPE_FS.
Just so I understand, your patch below is required in order to make what
LLD function with scsi-mq..?
Thanks!
--nab
> Thanks!
>
> diff --git a/drivers/scsi/scsi-mq.c b/drivers/scsi/scsi-mq.c
> index ca6ff67..d8cc7a4 100644
> --- a/drivers/scsi/scsi-mq.c
> +++ b/drivers/scsi/scsi-mq.c
> @@ -155,6 +155,7 @@ void scsi_mq_done(struct scsi_cmnd *sc)
> static struct blk_mq_ops scsi_mq_ops = {
> .queue_rq = scsi_mq_queue_rq,
> .map_queue = blk_mq_map_queue,
> + .timeout = scsi_times_out,
> .alloc_hctx = blk_mq_alloc_single_hw_queue,
> .free_hctx = blk_mq_free_single_hw_queue,
> };
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 65360db..33aa373 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -283,7 +283,10 @@ int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
> /*
> * head injection *required* here otherwise quiesce won't work
> */
> - blk_execute_rq(req->q, NULL, req, 1);
> + if (q->mq_ops)
> + blk_mq_execute_rq(req->q, req);
> + else
> + blk_execute_rq(req->q, NULL, req, 1);
>
> /*
> * Some devices (USB mass-storage in particular) may transfer
> @@ -298,12 +301,8 @@ int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
> *resid = req->resid_len;
> ret = req->errors;
> out:
> - if (q->mq_ops) {
> - printk("scsi_execute(): Calling blk_mq_free_request >>>\n");
> - blk_mq_free_request(req);
> - } else {
> + if (!q->mq_ops)
> blk_put_request(req);
> - }
>
> return ret;
> }
>
>
> > And personally, can't wait to run it on the laptop! That's right, I
> > alpha test on the laptop.
> >
> > --
> > Jens Axboe
> >
>
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