Re: [LTP] [PATCH] sched/rt: Disallow writing invalid values to sched_rt_period_us

[Petr Vorel]

> Hi!
> > Documentation/scheduller/sched-rt-group.rst [1] specifies this as values from -1 to
> > (INT_MAX - 1), I guess due int range. Looking into proc_dointvec_minmax() [2]
> > even INT_MAX would pass the check. I suppose we can do nothing about that,
> > because there is no value in sysctl_vals[] which would represent INT_MAX - 1.

> > And you specify in LTP test range: from -1 to INT_MAX.

> > But even much shorter value than INT_MAX fails:

> > $ echo 1234567 > /proc/sys/kernel/sched_rt_runtime_us
> > sh: echo: write error: Invalid argument

> That is because runtime_us must be < period_us by definition, since
> runtime_us defines how much time is allocated from the period_us. I
> guess that this is not described good enough in the kernel docs.

Thanks for clarification. +1 for docs update.

Kind regards,
Petr