Re: [Xenomai-core] [PATCH 1/6] Handle priority changes of SCHED_RR tasks

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

Jan Kiszka wrote:
> If shadowed Linux tasks with SCHED_RR policy change their priority,
> do_setsched_event currenty ignores this. Extend the condition to catch
> this case as well.
> 
> Signed-off-by: Jan Kiszka <jan.kiszka@domain.hid>
> ---
> 
>  ksrc/nucleus/shadow.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/ksrc/nucleus/shadow.c b/ksrc/nucleus/shadow.c
> index bd3bb3d..9f81c32 100644
> --- a/ksrc/nucleus/shadow.c
> +++ b/ksrc/nucleus/shadow.c
> @@ -2312,7 +2312,7 @@ static inline void do_setsched_event(struct task_struct *p, int priority)
>  	union xnsched_policy_param param;
>  	struct xnsched *sched;
>  
> -	if (!thread || p->policy != SCHED_FIFO)
> +	if (!thread || (p->policy != SCHED_FIFO && p->policy != SCHED_RR))
>  		return;

After some thinking about it, I think this is the wrong way to go. When
the user-space requests SCHED_RR, only the shadow should use SCHED_RR,
the linux thread should keep using SCHED_FIFO. We do not want two
schedulers to do round-robin, this would result in unpredictable behaviour.

-- 
                                                 Gilles.