Virtualization - Aug 2022 - [PATCH v1 2/2] Drivers: virtio: balloon: Report inflated memory

On Aug 9, 2022, at 2:53 AM, Alexander Atanasov <alexander.atanasov at
virtuozzo.com> wrote:
> Update the value in page_alloc on balloon fill/leak.
Some general comments if this patch goes forward.

Please cc pv-drivers at vmware.com in the future.
> 
> Cc: David Hildenbrand <david at redhat.com>
> Cc: Wei Liu <wei.liu at kernel.org>
> Cc: Nadav Amit <namit at vmware.com>
> 
> Signed-off-by: Alexander Atanasov <alexander.atanasov at
virtuozzo.com>
> ---
> drivers/virtio/virtio_balloon.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
> 
> Firts user, other balloons i will do if it is accepted to avoid too much
emails.
> 
> 
> diff --git a/drivers/virtio/virtio_balloon.c
b/drivers/virtio/virtio_balloon.c
> index b9737da6c4dd..e2693ffbd48b 100644
> --- a/drivers/virtio/virtio_balloon.c
> +++ b/drivers/virtio/virtio_balloon.c
> @@ -208,6 +208,16 @@ static void set_page_pfns(struct virtio_balloon *vb,
> 					  page_to_balloon_pfn(page) + i);
> }
> 
> +static void update_meminfo(struct virtio_balloon *vb)
Putting aside the less-than-optimal function name, I would like to ask that
any new generic balloon logic would go into balloon_compaction.[hc] as much
as possible. I made the effort to reuse this infrastructure (which is now
used by both VMware and virtio), and would prefer to share as much code as
possible.

For instance, I would appreciate if the update upon inflate would go into
balloon_page_list_enqueue() and balloon_page_enqueue(). VMware's 2MB pages
logic is not shared, so it would require a change that is specific for
VMware code.