From: Omar Sandoval <osandov@osandov.com> To: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org, linux-nvme@lists.infradead.org Subject: Re: [PATCH 3/8] blk-mq: add mq_ops->commit_rqs() Date: Tue, 27 Nov 2018 15:43:03 -0800 [thread overview] Message-ID: <20181127234303.GC846@vader> (raw) In-Reply-To: <20181126163556.5181-4-axboe@kernel.dk> On Mon, Nov 26, 2018 at 09:35:51AM -0700, Jens Axboe wrote: > blk-mq passes information to the hardware about any given request being > the last that we will issue in this sequence. The point is that hardware > can defer costly doorbell type writes to the last request. But if we run > into errors issuing a sequence of requests, we may never send the request > with bd->last == true set. For that case, we need a hook that tells the > hardware that nothing else is coming right now. > > For failures returned by the drivers ->queue_rq() hook, the driver is > responsible for flushing pending requests, if it uses bd->last to > optimize that part. This works like before, no changes there. Reviewed-by: Omar Sandoval <osandov@fb.com> > Signed-off-by: Jens Axboe <axboe@kernel.dk> > --- > include/linux/blk-mq.h | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h > index ca0520ca6437..1fd139b65a6e 100644 > --- a/include/linux/blk-mq.h > +++ b/include/linux/blk-mq.h > @@ -117,6 +117,7 @@ struct blk_mq_queue_data { > > typedef blk_status_t (queue_rq_fn)(struct blk_mq_hw_ctx *, > const struct blk_mq_queue_data *); > +typedef void (commit_rqs_fn)(struct blk_mq_hw_ctx *); > /* takes rq->cmd_flags as input, returns a hardware type index */ > typedef int (rq_flags_to_type_fn)(struct request_queue *, unsigned int); > typedef bool (get_budget_fn)(struct blk_mq_hw_ctx *); > @@ -144,6 +145,15 @@ struct blk_mq_ops { > */ > queue_rq_fn *queue_rq; > > + /* > + * If a driver uses bd->last to judge when to submit requests to > + * hardware, it must define this function. In case of errors that > + * make us stop issuing further requests, this hook serves the > + * purpose of kicking the hardware (which the last request otherwise > + * would have done). > + */ > + commit_rqs_fn *commit_rqs; > + > /* > * Return a queue map type for the given request/bio flags > */ > -- > 2.17.1 >
WARNING: multiple messages have this Message-ID (diff)
From: osandov@osandov.com (Omar Sandoval) Subject: [PATCH 3/8] blk-mq: add mq_ops->commit_rqs() Date: Tue, 27 Nov 2018 15:43:03 -0800 [thread overview] Message-ID: <20181127234303.GC846@vader> (raw) In-Reply-To: <20181126163556.5181-4-axboe@kernel.dk> On Mon, Nov 26, 2018@09:35:51AM -0700, Jens Axboe wrote: > blk-mq passes information to the hardware about any given request being > the last that we will issue in this sequence. The point is that hardware > can defer costly doorbell type writes to the last request. But if we run > into errors issuing a sequence of requests, we may never send the request > with bd->last == true set. For that case, we need a hook that tells the > hardware that nothing else is coming right now. > > For failures returned by the drivers ->queue_rq() hook, the driver is > responsible for flushing pending requests, if it uses bd->last to > optimize that part. This works like before, no changes there. Reviewed-by: Omar Sandoval <osandov at fb.com> > Signed-off-by: Jens Axboe <axboe at kernel.dk> > --- > include/linux/blk-mq.h | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h > index ca0520ca6437..1fd139b65a6e 100644 > --- a/include/linux/blk-mq.h > +++ b/include/linux/blk-mq.h > @@ -117,6 +117,7 @@ struct blk_mq_queue_data { > > typedef blk_status_t (queue_rq_fn)(struct blk_mq_hw_ctx *, > const struct blk_mq_queue_data *); > +typedef void (commit_rqs_fn)(struct blk_mq_hw_ctx *); > /* takes rq->cmd_flags as input, returns a hardware type index */ > typedef int (rq_flags_to_type_fn)(struct request_queue *, unsigned int); > typedef bool (get_budget_fn)(struct blk_mq_hw_ctx *); > @@ -144,6 +145,15 @@ struct blk_mq_ops { > */ > queue_rq_fn *queue_rq; > > + /* > + * If a driver uses bd->last to judge when to submit requests to > + * hardware, it must define this function. In case of errors that > + * make us stop issuing further requests, this hook serves the > + * purpose of kicking the hardware (which the last request otherwise > + * would have done). > + */ > + commit_rqs_fn *commit_rqs; > + > /* > * Return a queue map type for the given request/bio flags > */ > -- > 2.17.1 >
next prev parent reply other threads:[~2018-11-27 23:43 UTC|newest] Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-11-26 16:35 [PATCHSET 0/8] block plugging improvements Jens Axboe 2018-11-26 16:35 ` Jens Axboe 2018-11-26 16:35 ` [PATCH 1/8] block: sum requests in the plug structure Jens Axboe 2018-11-26 16:35 ` Jens Axboe 2018-11-26 17:02 ` Christoph Hellwig 2018-11-26 17:02 ` Christoph Hellwig 2018-11-26 16:35 ` [PATCH 2/8] block: improve logic around when to sort a plug list Jens Axboe 2018-11-26 16:35 ` Jens Axboe 2018-11-27 23:31 ` Omar Sandoval 2018-11-27 23:31 ` Omar Sandoval 2018-11-27 23:49 ` Jens Axboe 2018-11-27 23:49 ` Jens Axboe 2018-11-27 23:55 ` Omar Sandoval 2018-11-27 23:55 ` Omar Sandoval 2018-11-27 23:59 ` Jens Axboe 2018-11-27 23:59 ` Jens Axboe 2018-11-28 0:05 ` Omar Sandoval 2018-11-28 0:05 ` Omar Sandoval 2018-11-28 0:16 ` Jens Axboe 2018-11-28 0:16 ` Jens Axboe 2018-11-26 16:35 ` [PATCH 3/8] blk-mq: add mq_ops->commit_rqs() Jens Axboe 2018-11-26 16:35 ` Jens Axboe 2018-11-27 23:43 ` Omar Sandoval [this message] 2018-11-27 23:43 ` Omar Sandoval 2018-11-28 1:38 ` Ming Lei 2018-11-28 1:38 ` Ming Lei 2018-11-28 7:16 ` Christoph Hellwig 2018-11-28 7:16 ` Christoph Hellwig 2018-11-28 12:54 ` Jens Axboe 2018-11-28 12:54 ` Jens Axboe 2018-11-26 16:35 ` [PATCH 4/8] nvme: implement mq_ops->commit_rqs() hook Jens Axboe 2018-11-26 16:35 ` Jens Axboe 2018-11-28 7:20 ` Christoph Hellwig 2018-11-28 7:20 ` Christoph Hellwig 2018-11-28 13:07 ` Jens Axboe 2018-11-28 13:07 ` Jens Axboe 2018-11-26 16:35 ` [PATCH 5/8] virtio_blk: " Jens Axboe 2018-11-26 16:35 ` Jens Axboe 2018-11-27 23:45 ` Omar Sandoval 2018-11-27 23:45 ` Omar Sandoval 2018-11-28 3:05 ` Michael S. Tsirkin 2018-11-28 3:05 ` Michael S. Tsirkin 2018-11-28 2:10 ` Ming Lei 2018-11-28 2:10 ` Ming Lei 2018-11-28 2:34 ` Jens Axboe 2018-11-28 2:34 ` Jens Axboe 2018-11-29 1:23 ` Ming Lei 2018-11-29 1:23 ` Ming Lei 2018-11-29 2:19 ` Jens Axboe 2018-11-29 2:19 ` Jens Axboe 2018-11-29 2:51 ` Ming Lei 2018-11-29 2:51 ` Ming Lei 2018-11-29 3:13 ` Jens Axboe 2018-11-29 3:13 ` Jens Axboe 2018-11-29 3:27 ` Ming Lei 2018-11-29 3:27 ` Ming Lei 2018-11-29 3:53 ` Jens Axboe 2018-11-29 3:53 ` Jens Axboe 2018-11-28 7:21 ` Christoph Hellwig 2018-11-28 7:21 ` Christoph Hellwig 2018-11-26 16:35 ` [PATCH 6/8] ataflop: " Jens Axboe 2018-11-26 16:35 ` Jens Axboe 2018-11-27 23:46 ` Omar Sandoval 2018-11-27 23:46 ` Omar Sandoval 2018-11-28 7:22 ` Christoph Hellwig 2018-11-28 7:22 ` Christoph Hellwig 2018-11-28 13:09 ` Jens Axboe 2018-11-28 13:09 ` Jens Axboe 2018-11-26 16:35 ` [PATCH 7/8] blk-mq: use bd->last == true for list inserts Jens Axboe 2018-11-26 16:35 ` Jens Axboe 2018-11-27 23:49 ` Omar Sandoval 2018-11-27 23:49 ` Omar Sandoval 2018-11-27 23:51 ` Jens Axboe 2018-11-27 23:51 ` Jens Axboe 2018-11-28 1:49 ` Ming Lei 2018-11-28 1:49 ` Ming Lei 2018-11-28 2:37 ` Jens Axboe 2018-11-28 2:37 ` Jens Axboe 2018-11-26 16:35 ` [PATCH 8/8] blk-mq: add plug case for devices that implement ->commits_rqs() Jens Axboe 2018-11-26 16:35 ` Jens Axboe 2018-11-28 7:26 ` Christoph Hellwig 2018-11-28 7:26 ` Christoph Hellwig 2018-11-28 13:11 ` Jens Axboe 2018-11-28 13:11 ` Jens Axboe
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