Re: [PATCH] chrt: Make priority optional for policies that don't use it

On Mon, Jun 16, 2025 at 12:52:18AM +0530, Madadi Vineeth Reddy wrote:
> Currently, chrt requires a priority argument even for scheduling
> policies like SCHED_OTHER and SCHED_BATCH, which ignore it.
> 
> This change relaxes that requirement. Now, priority is only expected
> for SCHED_FIFO and SCHED_RR. For other policies, a default value of 0
> is set internally and no argument is required on the command line.
> 
> This simplifies usage when modifying runtime parameters like
> --sched-runtime for non-realtime tasks.
> 
> For example, to change the EEVDF tunable base_slice, one currently
> needs to run:
> chrt -v -o -T 1000000 -p 0 $PID
> 
> Passing '0' after -p is not intutive and not required as priority is
> not applicable to SCHED_OTHER tasks. Now with this patch, one can do:
> chrt -v -o -T 1000000 -p $PID
> 
> Passing '0' still works ensuring ABI doesn't break.

Looks good. It would be nice to update the man page and add a note  
that -p is not required since util-linux v2.42.

> +	bool policy_needs_priority = (ctl->policy == SCHED_FIFO || ctl->policy == SCHED_RR);

Nitpicking... can't we use a shorter name, for example "need_prio"? ;-)

    Karel

-- 
 Karel Zak  <[email protected]>
 http://karelzak.blogspot.com