Re: [PATCH v8 05/16] sched/core: Allow sched_setattr() to use the current policy

[Peter Zijlstra]

On Thu, May 09, 2019 at 10:18:07AM +0100, Patrick Bellasi wrote:
> On 08-May 21:21, Peter Zijlstra wrote:
> > On Tue, Apr 02, 2019 at 11:41:41AM +0100, Patrick Bellasi wrote:
> > > diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h
> > > index 22627f80063e..075c610adf45 100644
> > > --- a/include/uapi/linux/sched.h
> > > +++ b/include/uapi/linux/sched.h
> > > @@ -40,6 +40,8 @@
> > >  /* SCHED_ISO: reserved but not implemented yet */
> > >  #define SCHED_IDLE		5
> > >  #define SCHED_DEADLINE		6
> > > +/* Must be the last entry: used to sanity check attr.policy values */
> > > +#define SCHED_POLICY_MAX	SCHED_DEADLINE
> > 
> > This is a wee bit sad to put in a uapi header; but yeah, where else :/
> > 
> > Another option would be something like:
> > 
> > enum {
> > 	SCHED_NORMAL = 0,
> > 	SCHED_FIFO = 1,
> > 	SCHED_RR = 2,
> > 	SCHED_BATCH = 3,
> > 	/* SCHED_ISO = 4, reserved */
> > 	SCHED_IDLE = 5,
> > 	SCHED_DEADLINE = 6,
> > 	SCHED_POLICY_NR
> > };
> 
> I just wanted to minimize the changes by keeping the same structure...
> If you prefer the above I can add a refactoring patch just to update
> existing definitions before adding this patch...

Right; I've no idea really. The thing that started all this was adding
that define to UAPI. Maybe we can do without it and instead put in a
comment to check sched_setattr() any time we add a new policy and just
hard code the thing.