Re: [Qemu-devel] [PATCH v2 1/1] virtio-balloon: include statistics of disk/file caches

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Feb 13, 2018 at 12:29:39PM -0800, Jonathan Helman wrote:
> 
> 
> On 02/05/2018 04:08 AM, Tomáš Golembiovský wrote:
> > ping
> > 
> > On Tue,  5 Dec 2017 13:14:46 +0100
> > Tomáš Golembiovský <tgolembi@redhat.com> wrote:
> > 
> 
> It would be good to include the corresponding upstream kernel change in the
> commit message. This would be similar to a previous change:
> https://lists.gnu.org/archive/html/qemu-devel/2016-02/msg05555.html

good idea, but this has been merged by now.

> > > Signed-off-by: Tomáš Golembiovský <tgolembi@redhat.com>
> > > ---
> > >   hw/virtio/virtio-balloon.c                      | 1 +
> > >   include/standard-headers/linux/virtio_balloon.h | 3 ++-
> > >   2 files changed, 3 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
> > > index 37cde38982..8141326a51 100644
> > > --- a/hw/virtio/virtio-balloon.c
> > > +++ b/hw/virtio/virtio-balloon.c
> > > @@ -50,6 +50,7 @@ static const char *balloon_stat_names[] = {
> > >      [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory",
> > >      [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory",
> > >      [VIRTIO_BALLOON_S_AVAIL] = "stat-available-memory",
> > > +   [VIRTIO_BALLOON_S_CACHES] = "stat-disk-caches",
> > >      [VIRTIO_BALLOON_S_NR] = NULL
> > >   };
> > > diff --git a/include/standard-headers/linux/virtio_balloon.h b/include/standard-headers/linux/virtio_balloon.h
> > > index 9d06ccd066..7b0a41b8fc 100644
> > > --- a/include/standard-headers/linux/virtio_balloon.h
> > > +++ b/include/standard-headers/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 */
> 
> I've been wondering, VIRTIO_BALLOON_S_AVAIL is not in the virtio spec (see
> Section 5.5.6.3). It seems like this header file needs to be in sync with
> the virtio spec in order to make this change.
> 
> I have a similar change to add a new statistic and was wondering this.

Absolutely. Tomáš?

> > > +#define VIRTIO_BALLOON_S_NR       8
> > >   /*
> > >    * Memory statistics structure.
> > > -- 
> > > 2.15.1
> > > 
> > 
> > 
> 
> You need to add your new stat to the list of stats in
> docs/virtio-balloon-stats.txt.
> 
> Jon

Can't hurt, I agree.

-- 
MST