From: "Michael S. Tsirkin" <mst@redhat.com>
To: Roman Kagan <rkagan@virtuozzo.com>,
qemu-devel@nongnu.org, Ladi Prosek <lprosek@redhat.com>,
Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 2/2] virtio-balloon: resume collecting stats on vmload
Date: Tue, 6 Sep 2016 04:45:13 +0300 [thread overview]
Message-ID: <20160906044457-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20160905080236.bbk2ugjajalyqptv@rkaganb.sw.ru>
On Mon, Sep 05, 2016 at 11:02:36AM +0300, Roman Kagan wrote:
> On Sat, Sep 03, 2016 at 01:53:53AM +0300, Michael S. Tsirkin wrote:
> > On Fri, Sep 02, 2016 at 10:21:58AM +0300, Roman Kagan wrote:
> > > On Thu, Sep 01, 2016 at 10:26:54PM +0300, Michael S. Tsirkin wrote:
> > > > I'm sorry - I don't like this patch. This means that
> > > > virtio_balloon_receive_stats will be called and will poke
> > > > at the ring even if the ring was never kicked.
> > >
> > > I'm not sure I understand what the problem is with that:
> > > virtio_balloon_receive_stats just returns early if virtio_queue_empty(),
> > > which is no more poking at the ring than is already done in virtio_load.
> >
> > Generally we should not look at ring until there was a kick.
>
> How else would you recover ->inuse?
>
> Roman.
We seem to do this:
+ vdev->vq[i].inuse = vdev->vq[i].last_avail_idx -
+ vdev->vq[i].used_idx;
Is this wrong?
--
MST
next prev parent reply other threads:[~2016-09-06 1:45 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-01 18:13 [Qemu-devel] [PATCH 0/2] virtio-balloon: resume collecting stats on vmload Roman Kagan
2016-09-01 18:13 ` [Qemu-devel] [PATCH 1/2] virtio: add virtqueue_rewind Roman Kagan
2016-09-01 18:14 ` [Qemu-devel] [PATCH 2/2] virtio-balloon: resume collecting stats on vmload Roman Kagan
2016-09-01 19:26 ` Michael S. Tsirkin
2016-09-02 7:21 ` Roman Kagan
2016-09-02 22:53 ` Michael S. Tsirkin
2016-09-05 8:02 ` Roman Kagan
2016-09-06 1:45 ` Michael S. Tsirkin [this message]
2016-09-06 6:50 ` Roman Kagan
2016-09-06 10:15 ` Michael S. Tsirkin
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