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From: Keith Busch <kbusch@kernel.org>
To: Kanchan Joshi <joshiiitr@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>,
	linux-nvme@lists.infradead.org, Sagi Grimberg <sagi@grimberg.me>,
	Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org,
	Yuanyuan Zhong <yzhong@purestorage.com>,
	Casey Chen <cachen@purestorage.com>
Subject: Re: [PATCHv2 5/5] nvme: allow user passthrough commands to poll
Date: Mon, 17 May 2021 10:14:43 -0700	[thread overview]
Message-ID: <20210517171443.GB2709391@dhcp-10-100-145-180.wdc.com> (raw)
In-Reply-To: <CA+1E3rLD7Zx2iKtUoTBVc4VXBj2ohXFeXSw59umBZ3Q=QEA0xQ@mail.gmail.com>

On Mon, May 17, 2021 at 10:25:21PM +0530, Kanchan Joshi wrote:
> On Mon, Apr 26, 2021 at 8:46 PM Keith Busch <kbusch@kernel.org> wrote:
> >
> > On Mon, Apr 26, 2021 at 04:43:16PM +0200, Christoph Hellwig wrote:
> > > On Fri, Apr 23, 2021 at 03:05:58PM -0700, Keith Busch wrote:
> > > > The block layer knows how to deal with polled requests. Let the NVMe
> > > > driver use the previously reserved user "flags" fields to define an
> > > > option to allocate the request from the polled hardware contexts. If
> > > > polling is not enabled, then the block layer will automatically fallback
> > > > to a non-polled request.
> > >
> > > So this only support synchronous polling for a single command.  What
> > > use case do we have for that?  I think io_uring based polling would
> > > be much more useful once we support NVMe passthrough through that.
> >
> > There is no significant use case here. I just needed a simple way to
> > test the polled exec from earlier in the series. It was simple enough so
> > I included the patch here, but it's really not important compared to the
> > preceeding patches.
> 
> It would be great to see this in at some point; helps in making
> passthrough more useful.
> I'll look into integrating this with async-passthrough.

Right, async ioctl would really provide better justification for
passthrough polling. I'll post a new version of this series this week to
address the previously submitted feedback, but without this patch for
now.

      reply	other threads:[~2021-05-17 17:14 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-23 22:05 [PATCHv2 0/5] block and nvme passthrough error handling Keith Busch
2021-04-23 22:05 ` [PATCHv2 1/5] block: support polling through blk_execute_rq Keith Busch
2021-04-26  6:34   ` Ming Lei
2021-04-26 14:35   ` Christoph Hellwig
2021-05-17 16:43   ` Kanchan Joshi
2021-04-23 22:05 ` [PATCHv2 2/5] nvme: use blk_execute_rq() for passthrough commands Keith Busch
2021-04-26 14:35   ` Christoph Hellwig
2021-04-23 22:05 ` [PATCHv2 3/5] block: return errors from blk_execute_rq() Keith Busch
2021-04-26  6:42   ` Ming Lei
2021-04-26 14:36   ` Christoph Hellwig
2021-04-23 22:05 ` [PATCHv2 4/5] nvme: use return value " Keith Busch
2021-04-26 14:42   ` Christoph Hellwig
2021-04-26 17:10   ` Yuanyuan Zhong
2021-04-26 17:15     ` Keith Busch
2021-04-26 17:39       ` Yuanyuan Zhong
2021-04-23 22:05 ` [PATCHv2 5/5] nvme: allow user passthrough commands to poll Keith Busch
2021-04-26 14:43   ` Christoph Hellwig
2021-04-26 15:15     ` Keith Busch
2021-05-17 16:55       ` Kanchan Joshi
2021-05-17 17:14         ` Keith Busch [this message]

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