From: Ming Lei <ming.lei@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: 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 19:15:21 +0800 [thread overview]
Message-ID: <20181217111520.GD1329@ming.t460p> (raw)
In-Reply-To: <20181217110857.GA5995@lst.de>
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.
Thanks,
Ming
next prev parent reply other threads:[~2018-12-17 11:15 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 [this message]
2018-12-17 11:16 ` Christoph Hellwig
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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