a...@linux.vnet.ibm.com wrote:
> Here are the corresponding changes to the Linux virtio driver...
>
> virtio: Add memory statistics reporting to the balloon driver
>
> When using ballooning to manage overcommitted memory on a host, a system
> for
> guests to communicate their memory usage to the host can provide
> information
> that will minimize the impact of ballooning on the guests. The current
> method
> employs a daemon running in each guest that communicates memory
> statistics to a
> host daemon at a specified time interval. The host daemon aggregates this
> information and inflates and/or deflates balloons according to the level
> of
> host memory pressure. This approach is effective but overly complex
> since a
> daemon must be installed inside each guest and coordinated to communicate
> with
> the host. A simpler approach is to collect memory statistics in the
> virtio
> balloon driver and communicate them to the host via the device config
> space.
>
> This patch enables the guest-side support by adding stats collection and
> reporting to the virtio balloon driver.
>
> Signed-off-by: Adam Litke <a...@us.ibm.com>
>
> diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
> index 3a43ebf..1029363 100644
> --- a/drivers/virtio/virtio.c
> +++ b/drivers/virtio/virtio.c
> @@ -135,6 +135,7 @@ static int virtio_dev_probe(struct device *_d)
> set_bit(i, dev->features);
>
> dev->config->finalize_features(dev);
> + printk("virtio_dev_probe: final features = %lx\n", dev->features[0]);
>
Looks like leftover debugging.
> err = drv->probe(dev);
> if (err)
> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
> index 200c22f..77cb953 100644
> --- a/drivers/virtio/virtio_balloon.c
> +++ b/drivers/virtio/virtio_balloon.c
> @@ -180,6 +180,45 @@ static void update_balloon_size(struct virtio_balloon
> *vb)
> &actual, sizeof(actual));
> }
>
> +static inline void update_stat(struct virtio_device *vdev, int feature,
> + unsigned long value, unsigned offset)
> +{
> + if (virtio_has_feature(vdev, feature)) {
> + vdev->config->set(vdev, offset, &value, sizeof(value));
>
I think this bit assumes a little endian guest. We shouldn't make that
assumption.
For virtio kernel patches, please CC the virtualization list and Rusty
as he's the maintainer. It wouldn't hurt to CC lkml either.
--
Regards,
Anthony Liguori
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