On Fri, Sep 23, 2016 at 04:47:57PM +0300, Denis V. Lunev wrote:
> From: Konstantin Neumoin <kneumoin@xxxxxxxxxxxxx>
>
> Patch
> Commit 3d2a3774c1b046f548ebea0391a602fd5685a307
> Author: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Date: Tue Mar 10 11:55:08 2015 +1030
> virtio-balloon: do not call blocking ops when !TASK_RUNNING
> has added a regression. Original code with wait_event_interruptible
> checked the condition before start waiting and started balloon operations
> if necessary.
I don't get it, sorry.
+ add_wait_queue(&vb->config_change, &wait);
+ for (;;) {
+ if ((diff = towards_target(vb)) != 0 ||
+ vb->need_stats_update ||
+ kthread_should_stop() ||
+ freezing(current))
+ break;
+ wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
+ }
+ remove_wait_queue(&vb->config_change, &wait);
Seems to check the condition before waiting.
The issue is more likely with this patch:
commit fad7b7b27b6a168ca8ebc84482043886f837b89d
Author: Petr Mladek <pmladek@xxxxxxxx>
Date: Mon Jan 25 17:38:05 2016 +0100
virtio_balloon: Use a workqueue instead of "vballoon" kthread
> Right now balloon is not inflated if ballon target is set before the
> driver is loaded.
>
> Signed-off-by: Konstantin Neumoin <kneumoin@xxxxxxxxxxxxx>
> Signed-off-by: Denis V. Lunev <den@xxxxxxxxxx>
> CC: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
> ---
> drivers/virtio/virtio_balloon.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
> index 4e7003d..0a6c10f 100644
> --- a/drivers/virtio/virtio_balloon.c
> +++ b/drivers/virtio/virtio_balloon.c
> @@ -577,6 +577,10 @@ static int virtballoon_probe(struct virtio_device *vdev)
>
> virtio_device_ready(vdev);
>
> + if (towards_target(vb))
> + virtballoon_changed(vdev);
> + update_balloon_size(vb);
> +
> return 0;
>
> out_del_vqs:
I know we have same thing on restore, but it seems bogus
there as well:
if (towards_target(vb))
virtballoon_changed(vdev);
update_balloon_size(vb);
makes no sense because virtballoon_changed merely queues
the work.
> --
> 2.7.4
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