Re: [Qemu-devel] [PATCH v3] virtio_balloon: include disk/file caches memory statistics

[Michael S. Tsirkin]

On Sun, Nov 12, 2017 at 01:05:38PM +0100, Tomáš Golembiovský wrote:
> Add a new field VIRTIO_BALLOON_S_CACHES to virtio_balloon memory
> statistics protocol. The value represents all disk/file caches.
> 
> In this case it corresponds to the sum of values
> Buffers+Cached+SwapCached from /proc/meminfo.
> 
> Signed-off-by: Tomáš Golembiovský <address@hidden>


I parked this on vhost branch, part of linux next.

> ---
>  drivers/virtio/virtio_balloon.c     | 4 ++++
>  include/uapi/linux/virtio_balloon.h | 3 ++-
>  2 files changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
> index f0b3a0b9d42f..d2bd13bbaf9f 100644
> --- a/drivers/virtio/virtio_balloon.c
> +++ b/drivers/virtio/virtio_balloon.c
> @@ -244,11 +244,13 @@ static unsigned int update_balloon_stats(struct 
> virtio_balloon *vb)
>       struct sysinfo i;
>       unsigned int idx = 0;
>       long available;
> +     unsigned long caches;
>  
>       all_vm_events(events);
>       si_meminfo(&i);
>  
>       available = si_mem_available();
> +     caches = global_node_page_state(NR_FILE_PAGES);
>  
>  #ifdef CONFIG_VM_EVENT_COUNTERS
>       update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN,
> @@ -264,6 +266,8 @@ static unsigned int update_balloon_stats(struct 
> virtio_balloon *vb)
>                               pages_to_bytes(i.totalram));
>       update_stat(vb, idx++, VIRTIO_BALLOON_S_AVAIL,
>                               pages_to_bytes(available));
> +     update_stat(vb, idx++, VIRTIO_BALLOON_S_CACHES,
> +                             pages_to_bytes(caches));
>  
>       return idx;
>  }
> diff --git a/include/uapi/linux/virtio_balloon.h 
> b/include/uapi/linux/virtio_balloon.h
> index 343d7ddefe04..4e8b8304b793 100644
> --- a/include/uapi/linux/virtio_balloon.h
> +++ b/include/uapi/linux/virtio_balloon.h
> @@ -52,7 +52,8 @@ struct virtio_balloon_config {
>  #define VIRTIO_BALLOON_S_MEMFREE  4   /* Total amount of free memory */
>  #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_NR       7
> +#define VIRTIO_BALLOON_S_CACHES   7   /* Disk caches */
> +#define VIRTIO_BALLOON_S_NR       8
>  
>  /*
>   * Memory statistics structure.
> -- 
> 2.15.0