From: Ming Lei <ming.lei@redhat.com>
To: Keith Busch <kbusch@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, hch@infradead.org,
Sagi Grimberg <sagi@grimberg.me>
Subject: Re: [PATCH 1/4] block: add mq_ops->queue_rqs hook
Date: Thu, 18 Nov 2021 10:14:37 +0800 [thread overview]
Message-ID: <YZW3DT0q4y3llSjc@T590> (raw)
In-Reply-To: <YZW0M61sJNMQIRVZ@C02CK6ZVMD6M>
On Wed, Nov 17, 2021 at 07:02:27PM -0700, Keith Busch wrote:
> On Thu, Nov 18, 2021 at 08:18:29AM +0800, Ming Lei wrote:
> > On Wed, Nov 17, 2021 at 12:41:01PM -0800, Keith Busch wrote:
> > > On Tue, Nov 16, 2021 at 08:38:04PM -0700, Jens Axboe wrote:
> > > > If we have a list of requests in our plug list, send it to the driver in
> > > > one go, if possible. The driver must set mq_ops->queue_rqs() to support
> > > > this, if not the usual one-by-one path is used.
> > >
> > > It looks like we still need to sync with the request_queue quiesce flag.
> >
> > Basically it is same with my previous post[1], but the above patch doesn't
> > handle request queue allocation/freeing correctly in case of BLK_MQ_F_BLOCKING.
>
> Thanks for the pointer. I also thought it may be just as well that blocking
> dispatchers don't get to use the optimized rqlist queueing,
Yeah, that is fine, but nvme-tcp may not benefit from the ->queue_rq() optimization.
> which would simplify quiesce to the normal rcu usage.
Normal dispatch code still need to check quiesced for blocking queue, so
srcu is still needed, not see easier way than srcu yet. Years ago, I
tried to replace the srcu with percpu-refcnt, which is still more
complicated than srcu, but srcu_index can be dropped.
Thanks,
Ming
next prev parent reply other threads:[~2021-11-18 2:15 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-17 3:38 [PATCHSET 0/4] Add support for list issue Jens Axboe
2021-11-17 3:38 ` [PATCH 1/4] block: add mq_ops->queue_rqs hook Jens Axboe
2021-11-17 6:25 ` Christoph Hellwig
2021-11-17 15:41 ` Jens Axboe
2021-11-17 8:20 ` Ming Lei
2021-11-17 15:43 ` Jens Axboe
2021-11-17 20:48 ` Keith Busch
2021-11-17 23:59 ` Ming Lei
2021-11-17 20:41 ` Keith Busch
2021-11-18 0:18 ` Ming Lei
2021-11-18 2:02 ` Keith Busch
2021-11-18 2:14 ` Ming Lei [this message]
2021-11-17 3:38 ` [PATCH 2/4] nvme: split command copy into a helper Jens Axboe
2021-11-17 6:15 ` Christoph Hellwig
2021-11-17 15:44 ` Jens Axboe
2021-11-18 7:54 ` Chaitanya Kulkarni
2021-11-17 3:38 ` [PATCH 3/4] nvme: separate command prep and issue Jens Axboe
2021-11-17 6:17 ` Christoph Hellwig
2021-11-17 15:45 ` Jens Axboe
2021-11-18 7:59 ` Chaitanya Kulkarni
2021-11-17 3:38 ` [PATCH 4/4] nvme: add support for mq_ops->queue_rqs() Jens Axboe
2021-11-17 8:39 ` Christoph Hellwig
2021-11-17 15:55 ` Jens Axboe
2021-11-17 15:58 ` Jens Axboe
2021-11-17 19:41 ` Keith Busch
-- strict thread matches above, loose matches on Subject: below --
2021-12-03 21:45 [PATCHSET v2 0/4] Add support for list issue Jens Axboe
2021-12-03 21:45 ` [PATCH 1/4] block: add mq_ops->queue_rqs hook Jens Axboe
2021-12-04 10:43 ` Hannes Reinecke
2021-12-04 20:13 ` Jens Axboe
2021-12-05 9:07 ` Hannes Reinecke
2021-12-05 13:09 ` Jens Axboe
2021-12-16 16:05 [PATCHSET v4 0/4] Add support for list issue Jens Axboe
2021-12-16 16:05 ` [PATCH 1/4] block: add mq_ops->queue_rqs hook Jens Axboe
2021-12-16 16:38 [PATCHSET v5 0/4] Add support for list issue Jens Axboe
2021-12-16 16:38 ` [PATCH 1/4] block: add mq_ops->queue_rqs hook Jens Axboe
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