Subject: Re: [PATCH] pseries/mobility: reset the RCU watchdogs after a LPM

From: "Nicholas Piggin" <[email-masked]>
Date: Mon, 28 Nov 2022 13:59:59 +1000

On Sat Nov 26, 2022 at 3:32 AM AEST, Laurent Dufour wrote:
> The RCU watchdog timer should be reset when restarting the CPU after a Live
> Partition Mobility operation.
>
> Signed-off-by: Laurent Dufour <[email-masked]>

Looks okay to me. xmon touches the softlockup watchdog explicitly but
is that for architectures with unsynchronized clocks maybe.

Acked-by: Nicholas Piggin <[email-masked]>

> ---
>  arch/powerpc/platforms/pseries/mobility.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
> index 634fac5db3f9..9e10f38dd9ad 100644
> --- a/arch/powerpc/platforms/pseries/mobility.c
> +++ b/arch/powerpc/platforms/pseries/mobility.c
> @@ -636,8 +636,10 @@ static int do_join(void *arg)
>  	}
>  	/*
>  	 * Execution may have been suspended for several seconds, so
> -	 * reset the watchdog.
> +	 * reset the watchdogs.
>  	 */
> +	rcu_cpu_stall_reset();
> +	/* touch_nmi_watchdog() also touch the soft lockup watchdog */
>  	touch_nmi_watchdog();
>  	return ret;
>  }
> -- 
> 2.38.1