From: "Michael S. Tsirkin" <mst@redhat.com>
To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: qemu-devel@nongnu.org, Doug Goldstein <cardoe@cardoe.com>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 2/2] virtio: disable notifications again after poll succeeded
Date: Fri, 13 Jan 2017 17:53:05 +0200 [thread overview]
Message-ID: <20170113175234-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20170112114612.14520-3-stefanha@redhat.com>
On Thu, Jan 12, 2017 at 11:46:11AM +0000, Stefan Hajnoczi wrote:
> While AioContext is in polling mode virtqueue notifications are not
> necessary. Some device virtqueue handlers enable notifications. Make
> sure they stay disabled to avoid unnecessary vmexits.
>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
So I'll put just the revert in today's pull request,
let's make sure this one is not causing regressions.
> ---
> hw/virtio/virtio.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index f04ab7a..34065c7 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -2126,6 +2126,9 @@ static bool virtio_queue_host_notifier_aio_poll(void *opaque)
> }
>
> virtio_queue_notify_aio_vq(vq);
> +
> + /* In case the handler function re-enabled notifications */
> + virtio_queue_set_notification(vq, 0);
> return true;
> }
>
> --
> 2.9.3
next prev parent reply other threads:[~2017-01-13 15:53 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-12 11:46 [Qemu-devel] [PATCH 0/2] virtio: revert virtio_queue_set_notification() nesting Stefan Hajnoczi
2017-01-12 11:46 ` [Qemu-devel] [PATCH 1/2] Revert "virtio: turn vq->notification into a nested counter" Stefan Hajnoczi
2017-01-12 11:46 ` [Qemu-devel] [PATCH 2/2] virtio: disable notifications again after poll succeeded Stefan Hajnoczi
2017-01-13 15:53 ` Michael S. Tsirkin [this message]
2017-01-12 16:57 ` [Qemu-devel] [PATCH 0/2] virtio: revert virtio_queue_set_notification() nesting Doug Goldstein
2017-01-12 20:05 ` Michael S. Tsirkin
2017-01-13 14:48 ` Doug Goldstein
2017-01-13 12:02 ` Stefan Hajnoczi
2017-01-13 15:15 ` Doug Goldstein
2017-01-16 10:46 ` Stefan Hajnoczi
2017-01-16 21:03 ` Doug Goldstein
2017-01-17 3:09 ` Michael S. Tsirkin
2017-01-17 9:49 ` Stefan Hajnoczi
2017-01-14 3:48 ` Richard Henderson
2017-01-16 23:31 ` Laszlo Ersek
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