From: Sasha Levin <levinsasha928@gmail.com>
To: Asias He <asias.hejun@gmail.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>,
Cyrill Gorcunov <gorcunov@gmail.com>, Ingo Molnar <mingo@elte.hu>,
Prasad Joshi <prasadjoshi124@gmail.com>,
kvm@vger.kernel.org
Subject: Re: [PATCH 1/2] kvm tools: Bring VIRTIO_BLK_F_SEG_MAX feature back to virtio blk
Date: Fri, 13 May 2011 18:26:39 +0300 [thread overview]
Message-ID: <1305300399.25256.20.camel@lappy> (raw)
In-Reply-To: <4DCD4184.3040803@gmail.com>
On Fri, 2011-05-13 at 22:34 +0800, Asias He wrote:
> On 05/13/2011 10:07 PM, Sasha Levin wrote:
> > On Fri, 2011-05-13 at 15:46 +0300, Pekka Enberg wrote:
> >> On 5/13/11 5:40 AM, Asias He wrote:
> >>> commit b764422bb0b46b00b896f6d4538ac3d3dde9e56b
> >>> (kvm tools: Add support for multiple virtio-blk)
> >>> removed the VIRTIO_BLK_F_SEG_MAX publishment to guest.
> >>>
> >>> There is no reason we should not support it. Just bring it back.
> >>>
> >>> Signed-off-by: Asias He<asias.hejun@gmail.com>
> >>
> >> Sasha?
> >
> > I'm not sure why it was removed, must have missed it when updating
> > struct blk_dev.
> >
> > On the other hand, why do we need to limit max segment size?
>
> That's because the number of entries in a scatter-gather operation must
> be less than the entries in the virt queue we can offer.
>
I thought that since it's the guest who allocates vq buffers and it's
the guest who does the sg ops, it won't attempt to do that.
But if thats the concern, then yes - lets add it to be safe.
--
Sasha.
next prev parent reply other threads:[~2011-05-13 16:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-13 2:40 [PATCH 1/2] kvm tools: Bring VIRTIO_BLK_F_SEG_MAX feature back to virtio blk Asias He
2011-05-13 2:40 ` [PATCH 2/2] kvm tools: Tune the command-line option Asias He
2011-05-13 12:46 ` [PATCH 1/2] kvm tools: Bring VIRTIO_BLK_F_SEG_MAX feature back to virtio blk Pekka Enberg
2011-05-13 14:07 ` Sasha Levin
2011-05-13 14:34 ` Asias He
2011-05-13 15:26 ` Sasha Levin [this message]
2011-05-13 16:16 ` Asias He
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1305300399.25256.20.camel@lappy \
--to=levinsasha928@gmail.com \
--cc=asias.hejun@gmail.com \
--cc=gorcunov@gmail.com \
--cc=kvm@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=penberg@cs.helsinki.fi \
--cc=prasadjoshi124@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox