From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>,
kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>,
virtualization@lists.linux-foundation.org, khoa@us.ibm.com,
Tejun Heo <tj@kernel.org>
Subject: Re: [PATCH v2] virtio_blk: unlock vblk->lock during kick
Date: Mon, 04 Jun 2012 08:02:16 +0200 [thread overview]
Message-ID: <4FCC4F68.4020304@de.ibm.com> (raw)
In-Reply-To: <877gvn3kks.fsf@rustcorp.com.au>
On 04/06/12 03:57, Rusty Russell wrote:
> Unfortunately, this conflicts with Asias He's deadlock fix, which has
> us just using the block-layer-supplied spinlock.
>
> If we drop the lock around the kick as you suggest, we're playing with
> fire. All the virtio backends have an atomic notify, so they're OK,
> and the block layer *looks* safe at a glance, but there's no assurances.
Well, the kick itself returns early, but in the host every other action
is already asynchronously running - not caring about the guest locks at all.
So if removing the lock around the kick causes a problem, then the problem
is already present, no?
Christian
next prev parent reply other threads:[~2012-06-04 6:02 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-30 13:19 [PATCH v2] virtio_blk: unlock vblk->lock during kick Stefan Hajnoczi
2012-05-30 13:39 ` Christian Borntraeger
2012-06-04 1:57 ` Rusty Russell
2012-06-04 5:29 ` Michael S. Tsirkin
2012-06-04 6:02 ` Christian Borntraeger [this message]
2012-06-04 8:27 ` Stefan Hajnoczi
2012-06-04 8:35 ` Asias He
2012-06-04 8:57 ` Asias He
2012-06-01 4:38 ` Asias He
2012-06-01 7:58 ` Stefan Hajnoczi
-- strict thread matches above, loose matches on Subject: below --
2012-05-30 13:19 Stefan Hajnoczi
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=4FCC4F68.4020304@de.ibm.com \
--to=borntraeger@de.ibm.com \
--cc=khoa@us.ibm.com \
--cc=kvm@vger.kernel.org \
--cc=mst@redhat.com \
--cc=rusty@rustcorp.com.au \
--cc=stefanha@linux.vnet.ibm.com \
--cc=tj@kernel.org \
--cc=virtualization@lists.linux-foundation.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.