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From:   Nadav Amit <namit@vmware.com>
To:     Alexander Atanasov <alexander.atanasov@virtuozzo.com>
CC:     "Michael S. Tsirkin" <mst@redhat.com>,
        David Hildenbrand <david@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        "kernel@openvz.org" <kernel@openvz.org>,
        Wei Liu <wei.liu@kernel.org>,
        Linux Virtualization <virtualization@lists.linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Pv-drivers <Pv-drivers@vmware.com>
Subject: Re: [PATCH v1 2/2] Drivers: virtio: balloon: Report inflated memory
Thread-Topic: [PATCH v1 2/2] Drivers: virtio: balloon: Report inflated memory
Thread-Index: AQHYq9YDdj/O5CsJlUeEIqWy1OYxe62m18WA
Date:   Tue, 9 Aug 2022 17:44:49 +0000
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References: <20220809094933.2203087-1-alexander.atanasov@virtuozzo.com>
 <20220809095358.2203355-1-alexander.atanasov@virtuozzo.com>
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On Aug 9, 2022, at 2:53 AM, Alexander Atanasov <alexander.atanasov@virtuozz=
o.com> wrote:

> Update the value in page_alloc on balloon fill/leak.

Some general comments if this patch goes forward.

Please cc pv-drivers@vmware.com in the future.

>=20
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Wei Liu <wei.liu@kernel.org>
> Cc: Nadav Amit <namit@vmware.com>
>=20
> Signed-off-by: Alexander Atanasov <alexander.atanasov@virtuozzo.com>
> ---
> drivers/virtio/virtio_balloon.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>=20
> Firts user, other balloons i will do if it is accepted to avoid too much =
emails.
>=20
>=20
> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_ball=
oon.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);
> }
>=20
> +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.