Re: [PATCH v2] virtio_balloon: export hugetlb page allocation counts

[Jason Wang <jasowang@redhat.com>]

On 2018年03月20日 06:14, Jonathan Helman wrote:
> Export the number of successful and failed hugetlb page
> allocations via the virtio balloon driver. These 2 counts
> come directly from the vm_events HTLB_BUDDY_PGALLOC and
> HTLB_BUDDY_PGALLOC_FAIL.
>
> Signed-off-by: Jonathan Helman <jonathan.helman@oracle.com>

Reviewed-by: Jason Wang <jasowang@redhat.com>

> ---
>   drivers/virtio/virtio_balloon.c     | 6 ++++++
>   include/uapi/linux/virtio_balloon.h | 4 +++-
>   2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
> index dfe5684..6b237e3 100644
> --- a/drivers/virtio/virtio_balloon.c
> +++ b/drivers/virtio/virtio_balloon.c
> @@ -272,6 +272,12 @@ static unsigned int update_balloon_stats(struct virtio_balloon *vb)
>   				pages_to_bytes(events[PSWPOUT]));
>   	update_stat(vb, idx++, VIRTIO_BALLOON_S_MAJFLT, events[PGMAJFAULT]);
>   	update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]);
> +#ifdef CONFIG_HUGETLB_PAGE
> +	update_stat(vb, idx++, VIRTIO_BALLOON_S_HTLB_PGALLOC,
> +		    events[HTLB_BUDDY_PGALLOC]);
> +	update_stat(vb, idx++, VIRTIO_BALLOON_S_HTLB_PGFAIL,
> +		    events[HTLB_BUDDY_PGALLOC_FAIL]);
> +#endif
>   #endif
>   	update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMFREE,
>   				pages_to_bytes(i.freeram));
> diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h
> index 4e8b830..40297a3 100644
> --- a/include/uapi/linux/virtio_balloon.h
> +++ b/include/uapi/linux/virtio_balloon.h
> @@ -53,7 +53,9 @@ struct virtio_balloon_config {
>   #define VIRTIO_BALLOON_S_MEMTOT   5   /* Total amount of memory */
>   #define VIRTIO_BALLOON_S_AVAIL    6   /* Available memory as in /proc */
>   #define VIRTIO_BALLOON_S_CACHES   7   /* Disk caches */
> -#define VIRTIO_BALLOON_S_NR       8
> +#define VIRTIO_BALLOON_S_HTLB_PGALLOC  8  /* Hugetlb page allocations */
> +#define VIRTIO_BALLOON_S_HTLB_PGFAIL   9  /* Hugetlb page allocation failures */
> +#define VIRTIO_BALLOON_S_NR       10
>   
>   /*
>    * Memory statistics structure.

Not for this patch, but it looks to me that exporting such nr through 
uapi is fragile.

Thanks