From: Christoph Hellwig <hch@lst.de>
To: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Jeff Moyer <jmoyer@redhat.com>,
Mike Snitzer <snitzer@redhat.com>
Subject: Re: [PATCH V2 3/4] blk-mq: fix dispatch from sw queue
Date: Mon, 17 Dec 2018 12:16:58 +0100 [thread overview]
Message-ID: <20181217111658.GA6341@lst.de> (raw)
In-Reply-To: <20181217111520.GD1329@ming.t460p>
On Mon, Dec 17, 2018 at 07:15:21PM +0800, Ming Lei wrote:
> On Mon, Dec 17, 2018 at 12:08:57PM +0100, Christoph Hellwig wrote:
> >
> >
> > On Mon, Dec 17, 2018 at 06:42:47PM +0800, Ming Lei wrote:
> > > When requst is added to rq list of sw queue(ctx), the rq may be from
> > > different hctx, after multi queue mapping is introduced.
> > >
> > > So we have to put the request into one per-queue-type list inside
> > > sw queue, otherwise the request may be dispatched to wrong hw queue.
> >
> > Hmm. For one I don't think splitting the lock makes sense even for
> > split lists.
> > Second, do we really need different lists, or just take
>
> It depends if the driver/existed blk-mq code can work well if one
> request is dispatched to wrong hctx.
>
> > the type into account when dispatching from rq_list? I'm not really
>
> This way may be inefficient since the whole list has to be iterated once
> for finding all requests aimed to one specific hctx.
Then just update the changelog to make this clear, please!
next prev parent reply other threads:[~2018-12-17 11:17 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-17 10:42 [PATCH V2 0/4] blk-mq: queue mapping fix & improvement Ming Lei
2018-12-17 10:42 ` [PATCH V2 1/4] blk-mq: fix allocation for queue mapping table Ming Lei
2018-12-17 10:42 ` [PATCH V2 2/4] blk-mq: fix shared queue mapping Ming Lei
2018-12-17 10:57 ` Christoph Hellwig
2018-12-17 11:06 ` Ming Lei
2018-12-17 10:42 ` [PATCH V2 3/4] blk-mq: fix dispatch from sw queue Ming Lei
2018-12-17 11:08 ` Christoph Hellwig
2018-12-17 11:15 ` Ming Lei
2018-12-17 11:16 ` Christoph Hellwig [this message]
2018-12-17 10:42 ` [PATCH V2 4/4] blk-mq: export hctx->type in debugfs instead of sysfs Ming Lei
2018-12-17 10:57 ` Christoph Hellwig
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