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From: Stefan Hajnoczi <stefanha@redhat.com>
To: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-devel@nongnu.org, "Michal Privoznik" <mprivozn@redhat.com>,
	"Hanna Reitz" <hreitz@redhat.com>,
	qemu-block@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>,
	"Daniel P. Berrangé" <berrange@redhat.com>,
	"Michael Roth" <michael.roth@amd.com>,
	"Eduardo Habkost" <eduardo@habkost.net>,
	"Eric Blake" <eblake@redhat.com>,
	"Markus Armbruster" <armbru@redhat.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>
Subject: Re: [PATCH v4 4/4] virtio-blk: add iothread-vq-mapping parameter
Date: Thu, 18 Jan 2024 16:28:00 -0500	[thread overview]
Message-ID: <20240118212800.GA51691@fedora> (raw)
In-Reply-To: <ZYQ5PM8Hak2xDpIj@redhat.com>

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On Thu, Dec 21, 2023 at 02:10:20PM +0100, Kevin Wolf wrote:
> Am 20.12.2023 um 14:47 hat Stefan Hajnoczi geschrieben:
> > Add the iothread-vq-mapping parameter to assign virtqueues to IOThreads.
> > Store the vq:AioContext mapping in the new struct
> > VirtIOBlockDataPlane->vq_aio_context[] field and refactor the code to
> > use the per-vq AioContext instead of the BlockDriverState's AioContext.
> > 
> > Reimplement --device virtio-blk-pci,iothread= and non-IOThread mode by
> > assigning all virtqueues to the IOThread and main loop's AioContext in
> > vq_aio_context[], respectively.
> > 
> > The comment in struct VirtIOBlockDataPlane about EventNotifiers is
> > stale. Remove it.
> > 
> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> 
> I'm looking at virtio_blk_dma_restart_cb/bh(). It seems to run all
> queued requests in the iothread of the first vq, but when the requests
> complete, they will push the result to their original vq.
> 
> Do we know that the dataplane isn't started and won't be started until
> the requests complete? (I wouldn't expect so, because then moving to the
> AioContext of the BlockBackend wouldn't have been necessary either.) Or
> is there another reason why this is safe?

You are right. I overlooked this. I'll send a patch to make s->rq
multi-queue safe.

Stefan

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  reply	other threads:[~2024-01-18 21:29 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-20 13:47 [PATCH v4 0/4] virtio-blk: add iothread-vq-mapping parameter Stefan Hajnoczi
2023-12-20 13:47 ` [PATCH v4 1/4] qdev-properties: alias all object class properties Stefan Hajnoczi
2023-12-21 12:39   ` Kevin Wolf
2023-12-21 15:47     ` Stefan Hajnoczi
2023-12-20 13:47 ` [PATCH v4 2/4] string-output-visitor: show structs as "<omitted>" Stefan Hajnoczi
2023-12-20 13:47 ` [PATCH v4 3/4] qdev: add IOThreadVirtQueueMappingList property type Stefan Hajnoczi
2023-12-20 13:47 ` [PATCH v4 4/4] virtio-blk: add iothread-vq-mapping parameter Stefan Hajnoczi
2023-12-21 13:10   ` Kevin Wolf
2024-01-18 21:28     ` Stefan Hajnoczi [this message]
2023-12-21 13:40   ` Kevin Wolf
2024-01-19 13:41     ` Stefan Hajnoczi
2023-12-21 21:07 ` [PATCH v4 0/4] " Kevin Wolf

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