On Mon, Jun 3, 2019 at 10:04 AM Nitesh Narayan Lal <nitesh@xxxxxxxxxx> wrote:
>
> Enables the kernel to negotiate VIRTIO_BALLOON_F_HINTING feature with the
> host. If it is available and page_hinting_flag is set to true, page_hinting
> is enabled and its callbacks are configured along with the max_pages count
> which indicates the maximum number of pages that can be isolated and hinted
> at a time. Currently, only free pages of order >= (MAX_ORDER - 2) are
> reported. To prevent any false OOM max_pages count is set to 16.
>
> By default page_hinting feature is enabled and gets loaded as soon
> as the virtio-balloon driver is loaded. However, it could be disabled
> by writing the page_hinting_flag which is a virtio-balloon parameter.
>
> Signed-off-by: Nitesh Narayan Lal <nitesh@xxxxxxxxxx>
> ---
> drivers/virtio/virtio_balloon.c | 112 +++++++++++++++++++++++++++-
> include/uapi/linux/virtio_balloon.h | 14 ++++
> 2 files changed, 125 insertions(+), 1 deletion(-)
<snip>
> diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h
> index a1966cd7b677..25e4f817c660 100644
> --- a/include/uapi/linux/virtio_balloon.h
> +++ b/include/uapi/linux/virtio_balloon.h
> @@ -29,6 +29,7 @@
> #include <linux/virtio_types.h>
> #include <linux/virtio_ids.h>
> #include <linux/virtio_config.h>
> +#include <linux/page_hinting.h>
So this include breaks the build and from what I can tell it isn't
really needed. I deleted it in order to be able to build without
warnings about the file not being included in UAPI.
> /* The feature bitmap for virtio balloon */
> #define VIRTIO_BALLOON_F_MUST_TELL_HOST 0 /* Tell before reclaiming pages */
> @@ -36,6 +37,7 @@
> #define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */
> #define VIRTIO_BALLOON_F_FREE_PAGE_HINT 3 /* VQ to report free pages */
> #define VIRTIO_BALLOON_F_PAGE_POISON 4 /* Guest is using page poisoning */
> +#define VIRTIO_BALLOON_F_HINTING 5 /* Page hinting virtqueue */
>
> /* Size of a PFN in the balloon interface. */
> #define VIRTIO_BALLOON_PFN_SHIFT 12
> @@ -108,4 +110,16 @@ struct virtio_balloon_stat {
> __virtio64 val;
> } __attribute__((packed));
>
> +#ifdef CONFIG_PAGE_HINTING
> +/*
> + * struct hinting_data- holds the information associated with hinting.
> + * @phys_add: physical address associated with a page or the array holding
> + * the array of isolated pages.
> + * @size: total size associated with the phys_addr.
> + */
> +struct hinting_data {
> + __virtio64 phys_addr;
> + __virtio32 size;
> +};
> +#endif
> #endif /* _LINUX_VIRTIO_BALLOON_H */
> --
> 2.21.0
>
