From: Avi Kivity <avi@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>,
Rusty Russell <rusty@rustcorp.com.au>,
qemu-devel@nongnu.org, kvm@vger.kernel.org,
Hannes Reinecke <hare@suse.de>
Subject: Re: [Qemu-devel] [PATCH] virtio-blk: add SGI_IO passthru support
Date: Mon, 27 Apr 2009 12:15:31 +0300 [thread overview]
Message-ID: <49F577B3.5050706@redhat.com> (raw)
In-Reply-To: <20090427082914.GA383@lst.de>
Christoph Hellwig wrote:
> [had the qemu list address wrong the first time, reply to this message,
> not the previous if you were on Cc]
>
>
> Add support for SG_IO passthru (packet commands) to the virtio-blk
> backend. Conceptually based on an older patch from Hannes Reinecke
> but largely rewritten to match the code structure and layering in
> virtio-blk.
>
> Note that currently we issue the hose SG_IO synchronously. We could
> easily switch to async I/O, but that would required either bloating
> the VirtIOBlockReq by the size of struct sg_io_hdr or an additional
> memory allocation for each SG_IO request.
>
I think that's worthwhile. The extra bloat is trivial (especially as
the number of inflight virtio requests is tightly bounded), and stalling
the vcpu for requests is a pain.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2009-04-27 9:16 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20090427082606.GA32604@lst.de>
2009-04-27 8:29 ` [Qemu-devel] [PATCH] virtio-blk: add SGI_IO passthru support Christoph Hellwig
2009-04-27 9:15 ` Avi Kivity [this message]
2009-04-28 9:47 ` Christoph Hellwig
2009-04-27 14:36 ` [Qemu-devel] " Anthony Liguori
2009-04-28 9:51 ` Christoph Hellwig
2009-04-28 16:37 ` Anthony Liguori
2009-04-28 16:52 ` Christian Borntraeger
2009-04-29 10:48 ` Christoph Hellwig
2009-04-29 11:11 ` Paul Brook
2009-04-29 11:19 ` Christian Borntraeger
2009-04-29 11:29 ` Paul Brook
2009-04-29 11:21 ` Christoph Hellwig
2009-04-29 11:37 ` Paul Brook
2009-04-30 20:13 ` Christoph Hellwig
2009-04-30 20:55 ` Nicholas A. Bellinger
2009-04-30 21:49 ` Paul Brook
2009-04-30 21:56 ` Javier Guerra
2009-05-01 7:24 ` Christoph Hellwig
2009-05-01 11:08 ` Jamie Lokier
2009-05-01 14:28 ` Christoph Hellwig
2009-05-05 5:21 ` Rusty Russell
2009-04-28 19:09 ` Christian Borntraeger
2009-04-29 10:50 ` Christoph Hellwig
2009-04-29 11:07 ` Christian Borntraeger
2009-04-28 9:57 ` [Qemu-devel] [PATCH 2/2] virtio-blk: add SG_IO " Christoph Hellwig
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