From: Rusty Russell <rusty@rustcorp.com.au>
Cc: Amit Shah <amit.shah@redhat.com>,
Virtualization List <virtualization@lists.linux-foundation.org>,
miche@google.com, "Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH 1/2] virtio: console: Serialise control work
Date: Mon, 09 Jan 2012 13:03:59 +1030 [thread overview]
Message-ID: <87lipha9k8.fsf@rustcorp.com.au> (raw)
In-Reply-To: <0ee4e2fc77b40f1985391ce3f9b8a2cf3f729324.1325845993.git.amit.shah@redhat.com>
On Fri, 6 Jan 2012 16:19:07 +0530, Amit Shah <amit.shah@redhat.com> wrote:
> We currently allow multiple instances of the control work handler to run
> in parallel. This isn't expected to work; serialise access by disabling
> interrupts on new packets from the Host and enable them when all the
> existing ones are consumed.
>
> Testcase: hot-plug/unplug a port in a loop. Without this patch, some
> sysfs warnings are seen along with freezes. With the patch, all works
> fine.
Wait a sec... This might *work*, but it's not correct. Remember that
disabling callbacks is a hint, and it's cetainly not synchronous.
You need something else to explicitly prevent reentry.
Unapplied,
Rusty.
next prev parent reply other threads:[~2012-01-09 2:33 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-06 10:49 [PATCH 0/2] virtio: console: control queue race fixes Amit Shah
2012-01-06 10:49 ` [PATCH 1/2] virtio: console: Serialise control work Amit Shah
2012-01-09 2:33 ` Rusty Russell [this message]
2012-01-09 3:53 ` Amit Shah
2012-01-06 10:49 ` [PATCH 2/2] virtio: console: Disable callbacks for virtqueues at start of S4 freeze Amit Shah
2012-01-09 2:31 ` [PATCH 0/2] virtio: console: control queue race fixes Rusty Russell
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=87lipha9k8.fsf@rustcorp.com.au \
--to=rusty@rustcorp.com.au \
--cc=amit.shah@redhat.com \
--cc=miche@google.com \
--cc=mst@redhat.com \
--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.