On Wed, May 30, 2018 at 05:12:09PM +0800, Wei Wang wrote:
> On 05/29/2018 11:24 PM, Michael S. Tsirkin wrote:
> > On Tue, Apr 24, 2018 at 02:13:47PM +0800, Wei Wang wrote:
> > > +/*
> > > + * Balloon will report pages which were free at the time of this call.
> > > As the
> > > + * reporting happens asynchronously, dirty bit logging must be enabled
> > > before
> > > + * this call is made.
> > > + */
> > > +void balloon_free_page_start(void)
> > > +{
> > > + balloon_free_page_start_fn(balloon_opaque);
> > > +}
> > Please create notifier support, not a single global.
>
> OK. The start is called at the end of bitmap_sync, and the stop is called at
> the beginning of bitmap_sync. In this case, we will need to add two
> migration states, MIGRATION_STATUS_BEFORE_BITMAP_SYNC and
> MIGRATION_STATUS_AFTER_BITMAP_SYNC, right?
If that's the way you do it, you need to ask migration guys, not me.
>
> >
> > +static void virtio_balloon_poll_free_page_hints(void *opaque)
> > +{
> > + VirtQueueElement *elem;
> > + VirtIOBalloon *dev = opaque;
> > + VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> > + VirtQueue *vq = dev->free_page_vq;
> > + uint32_t id;
> > + size_t size;
> > +
> > + while (1) {
> > + qemu_mutex_lock(&dev->free_page_lock);
> > + while (dev->block_iothread) {
> > + qemu_cond_wait(&dev->free_page_cond, &dev->free_page_lock);
> > + }
> > +
> > + /*
> > + * If the migration thread actively stops the reporting, exit
> > + * immediately.
> > + */
> > + if (dev->free_page_report_status == FREE_PAGE_REPORT_S_STOP) {
> > Please refactor this : move loop body into a function so
> > you can do lock/unlock in a single place.
>
> Sounds good.
>
> >
> > +
> > +static bool virtio_balloon_free_page_support(void *opaque)
> > +{
> > + VirtIOBalloon *s = opaque;
> > + VirtIODevice *vdev = VIRTIO_DEVICE(s);
> > +
> > + return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT);
> > or if poison is negotiated.
>
> Will make it
> return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT) &&
> !virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON)
I mean the reverse:
virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT) ||
virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON)
If poison has been negotiated you must migrate the
guest supplied value even if you don't use it for hints.
>
>
> Best,
> Wei
