Re: [PATCH v2 2/3] powerpc/rtas: allow rescheduling while changing cpu states

From: Gautham R Shenoy <ego.lkml@gmail.com>
To: Nathan Lynch <nathanl@linux.ibm.com>
Cc: ego@linux.vnet.ibm.com, linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH v2 2/3] powerpc/rtas: allow rescheduling while changing cpu states
Date: Tue, 13 Aug 2019 22:47:30 +0530	[thread overview]
Message-ID: <CAHZ_5WyBjss+C2rY_zhr_BDFHEDNOq7-3T6um38uVj-Tj6jHtA@mail.gmail.com> (raw)
In-Reply-To: <20190802192926.19277-3-nathanl@linux.ibm.com>

On Sat, Aug 3, 2019 at 1:03 AM Nathan Lynch <nathanl@linux.ibm.com> wrote:
>
> rtas_cpu_state_change_mask() potentially operates on scores of cpus,
> so explicitly allow rescheduling in the loop body.
>

Are we seeing softlockups/rcu stalls while running this ?

> Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>

Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>

> ---
>  arch/powerpc/kernel/rtas.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
> index 05824eb4323b..b7ca2fde68a9 100644
> --- a/arch/powerpc/kernel/rtas.c
> +++ b/arch/powerpc/kernel/rtas.c
> @@ -16,6 +16,7 @@
>  #include <linux/capability.h>
>  #include <linux/delay.h>
>  #include <linux/cpu.h>
> +#include <linux/sched.h>
>  #include <linux/smp.h>
>  #include <linux/completion.h>
>  #include <linux/cpumask.h>
> @@ -898,6 +899,7 @@ static int rtas_cpu_state_change_mask(enum rtas_cpu_state state,
>                                 cpumask_clear_cpu(cpu, cpus);
>                         }
>                 }
> +               cond_resched();
>         }
>
>         return ret;
> --
> 2.20.1
>

-- 
Thanks and Regards
gautham.