From: "Michael S. Tsirkin" <mst@redhat.com>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Christoph Hellwig <hch@infradead.org>,
Chris Wright <chrisw@sous-sol.org>, Jens Axboe <axboe@kernel.dk>,
Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/5] virtio: support unlocked queue kick
Date: Thu, 6 Oct 2011 11:19:18 -0200 [thread overview]
Message-ID: <20111006131828.GC19023@redhat.com> (raw)
In-Reply-To: <87r52qgaf3.fsf@rustcorp.com.au>
On Thu, Oct 06, 2011 at 12:15:36PM +1030, Rusty Russell wrote:
> On Wed, 05 Oct 2011 15:54:05 -0400, Christoph Hellwig <hch@infradead.org> wrote:
> > Split virtqueue_kick to be able to do the actual notification outside the
> > lock protecting the virtqueue. This patch was originally done by
> > Stefan Hajnoczi, but I can't find the original one anymore and had to
> > recreated it from memory. Pointers to the original or corrections for
> > the commit message are welcome.
>
> An alternative to this is to update the ring on every virtqueue_add_buf.
> MST discussed this for virtio_net, and I think it's better in general.
>
> The only reason that it wasn't written that way originally is that the
> barriers make add_buf slightly more expensive.
>
> Cheers,
> Rusty.
With event index, I'm not sure that's enough to make the kick lockless
anymore.
--
MST
next prev parent reply other threads:[~2011-10-06 9:18 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-05 19:54 [PATCH 0/5] RFC: ->make_request support for virtio-blk Christoph Hellwig
2011-10-05 19:54 ` [PATCH 1/5] block: add bio_map_sg Christoph Hellwig
2011-10-05 22:51 ` Boaz Harrosh
2011-10-06 13:40 ` Christoph Hellwig
2011-10-05 19:54 ` [PATCH 2/5] virtio: support unlocked queue kick Christoph Hellwig
2011-10-06 8:42 ` Stefan Hajnoczi
[not found] ` <87r52qgaf3.fsf@rustcorp.com.au>
2011-10-06 13:19 ` Michael S. Tsirkin [this message]
2011-11-01 14:40 ` Michael S. Tsirkin
2011-11-02 3:19 ` Rusty Russell
2011-11-02 7:25 ` Christoph Hellwig
2011-11-03 4:01 ` Rusty Russell
2011-11-03 5:15 ` Rusty Russell
2011-11-03 6:45 ` Minchan Kim
2011-10-05 19:54 ` [PATCH 3/5] virtio-blk: remove the unused list of pending requests Christoph Hellwig
2011-10-05 19:54 ` [PATCH 4/5] virtio-blk: reimplement the serial attribute without using requests Christoph Hellwig
2011-10-05 19:54 ` [PATCH 5/5] virtio-blk: implement ->make_request Christoph Hellwig
2011-10-06 1:52 ` Rusty Russell
2011-10-06 13:42 ` Christoph Hellwig
2011-10-06 13:53 ` Jens Axboe
2011-10-05 20:31 ` [PATCH 0/5] RFC: ->make_request support for virtio-blk Vivek Goyal
2011-10-05 21:53 ` Christoph Hellwig
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