Re: [XENBUS PATCH] Kick the balloon thread in FdoStartDevice

[Paul Durrant <xadimgnik@xxxxxxxxx>]

On 13/06/2025 19:30, Tu Dinh wrote:
> Xenbus currently doesn't apply the dynamic memory targets at boot time.
How so?

The xenstore watch on memory/target signals the balloon thread's event 
so the watch registration in __FdoD3ToD0() should always wake the thread 
(since any watch registration triggers a spurious watch event).
> Force the balloon thread to update memory targets at boot.
>
> Signed-off-by: Tu Dinh <ngoc-tu.dinh@xxxxxxxxxx>
> ---
>   src/xenbus/fdo.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/src/xenbus/fdo.c b/src/xenbus/fdo.c
> index 3a4a1a2..c2e69fa 100644
> --- a/src/xenbus/fdo.c
> +++ b/src/xenbus/fdo.c
> @@ -3949,6 +3949,9 @@ not_active:
>   
>           ASSERT(__FdoIsActive(Fdo));
>   
> +        KeClearEvent(&Fdo->BalloonEvent);
> +        ThreadWake(Fdo->BalloonThread);
> +
>           //
>           // Balloon inflation should complete within a reasonable
>           // time (otherwise the target is probably unreasonable).