VIRTIO_BALLOON_HINT_BLOCK_PAGES
VIRTIO_BALLOON_HINT_BLOCK_PAGES);
blocks_to_free = pages_to_free / VIRTIO_BALLOON_HINT_BLOCK_PAGES;
return blocks_freed * VIRTIO_BALLOON_HINT_BLOCK_PAGES;
return vb->num_free_page_blocks * VIRTIO_BALLOON_HINT_BLOCK_PAGES;