Re: [PATCH v1 4/5] xen/balloon: try to merge system ram resources

[Jürgen Groß <jgross@xxxxxxxx>]

On 21.08.20 12:34, David Hildenbrand wrote:
> Let's reuse the new mechanism to merge system ram resources below the
> root. We are the only one hotplugging system ram (e.g., DIMMs don't apply),
> so this is safe to be used.
>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxxx>
> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
> Cc: Juergen Gross <jgross@xxxxxxxx>
> Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> Cc: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> Cc: Julien Grall <julien@xxxxxxx>
> Cc: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx>
> Cc: Baoquan He <bhe@xxxxxxxxxx>
> Cc: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
> ---
>   drivers/xen/balloon.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
> index 37ffccda8bb87..5ec73f752b8a7 100644
> --- a/drivers/xen/balloon.c
> +++ b/drivers/xen/balloon.c
> @@ -338,6 +338,10 @@ static enum bp_state reserve_additional_memory(void)
>         if (rc) {
>                 pr_warn("Cannot add additional memory (%i)\n", rc);
>                 goto err;
> +       } else {
> +               resource = NULL;
> +               /* Try to reduce the number of system ram resources. */
> +               merge_system_ram_resources(&iomem_resource);
>         }
I don't see the need for setting resource to NULL and to use an "else"
clause here.


Juergen