On Wed, Dec 21, 2016 at 02:52:25PM +0800, Liang Li wrote:
> Add a new feature which supports sending the page information
> with range array. The current implementation uses PFNs array,
> which is not very efficient. Using ranges can improve the
> performance of inflating/deflating significantly.
>
> Signed-off-by: Liang Li <[email protected]>
> Cc: Michael S. Tsirkin <[email protected]>
> Cc: Paolo Bonzini <[email protected]>
> Cc: Cornelia Huck <[email protected]>
> Cc: Amit Shah <[email protected]>
> Cc: Dave Hansen <[email protected]>
> Cc: Andrea Arcangeli <[email protected]>
> Cc: David Hildenbrand <[email protected]>
> ---
> include/uapi/linux/virtio_balloon.h | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/include/uapi/linux/virtio_balloon.h
> b/include/uapi/linux/virtio_balloon.h
> index 343d7dd..2f850bf 100644
> --- a/include/uapi/linux/virtio_balloon.h
> +++ b/include/uapi/linux/virtio_balloon.h
> @@ -34,10 +34,14 @@
> #define VIRTIO_BALLOON_F_MUST_TELL_HOST 0 /* Tell before reclaiming
> pages */
> #define VIRTIO_BALLOON_F_STATS_VQ 1 /* Memory Stats virtqueue */
> #define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */
> +#define VIRTIO_BALLOON_F_PAGE_RANGE 3 /* Send page info with ranges */
>
> /* Size of a PFN in the balloon interface. */
> #define VIRTIO_BALLOON_PFN_SHIFT 12
>
> +/* Bits width for the length of the pfn range */
What does this mean? Couldn't figure it out.
> +#define VIRTIO_BALLOON_NR_PFN_BITS 12
> +
> struct virtio_balloon_config {
> /* Number of pages host wants Guest to give up. */
> __u32 num_pages;
> @@ -82,4 +86,12 @@ struct virtio_balloon_stat {
> __virtio64 val;
> } __attribute__((packed));
>
> +/* Response header structure */
> +struct virtio_balloon_resp_hdr {
> + __le64 cmd : 8; /* Distinguish different requests type */
> + __le64 flag: 8; /* Mark status for a specific request type */
> + __le64 id : 16; /* Distinguish requests of a specific type */
> + __le64 data_len: 32; /* Length of the following data, in bytes */
This use of __le64 makes no sense. Just use u8/le16/le32 pls.
> +};
> +
> #endif /* _LINUX_VIRTIO_BALLOON_H */
> --
> 1.9.1
