Re: [PATCH v2 01/23] vmw_balloon: adjust BALLOON_DEFLATE when deflating while migrating

Lorenzo Stoakes
2026-01-15T10:24:04Z

On Thu, Jan 15, 2026 at 10:19:51AM +0100, David Hildenbrand (Red Hat) wrote:
> When we're effectively deflating the balloon while migrating a page
> because inflating the new page failed, we're not adjusting
> BALLOON_DEFLATE.
>
> Let's do that. This is a preparation for factoring out this handling to
> the core code, making it work in a similar way first.
>
> As this (deflating while migrating because of inflation error) is a
> corner case that I don't really expect to happen in practice
> and the stats are not that crucial, this likely doesn't classify as a fix.
>
> Reviewed-by: SeongJae Park <sj@kernel.org>
> Signed-off-by: David Hildenbrand (Red Hat) <david@kernel.org>

Seems reasonable to me, so:

Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

> ---
> drivers/misc/vmw_balloon.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
> index cc1d18b3df5ca..2cc34c4968fac 100644
> --- a/drivers/misc/vmw_balloon.c
> +++ b/drivers/misc/vmw_balloon.c
> @@ -1818,6 +1818,8 @@ static int vmballoon_migratepage(struct balloon_dev_info *b_dev_info,
> if (status == VMW_BALLOON_SUCCESS) {
> balloon_page_insert(&b->b_dev_info, newpage);
> __count_vm_event(BALLOON_MIGRATE);
> + } else {
> + __count_vm_event(BALLOON_DEFLATE);
> }
>
> /*
> --
> 2.52.0
>