Re: [PATCH 0/3] sched/rt fixes for 5.15, 5.10, 5.4

[Petr Vorel <pvorel@suse.cz>]

Hi all,

> Cyril Hrubis (3):
>   sched/rt: Fix sysctl_sched_rr_timeslice intial value
>   sched/rt: sysctl_sched_rr_timeslice show default timeslice after reset
>   sched/rt: Disallow writing invalid values to sched_rt_period_us

I'm sorry for the noise, while this patchset is working for 5.15 and 5.10,
it fails to compile on 5.4 due missing SYSCTL_ONE:

kernel/sysctl.c:477:14: error: ‘SYSCTL_NEG_ONE’ undeclared here (not in a function); did you mean ‘SYSCTL_ONE’?
   .extra1  = SYSCTL_NEG_ONE,
              ^~~~~~~~~~~~~~
              SYSCTL_ONE

This is because 78e36f3b0dae ("sysctl: move some boundary constants from
sysctl.c to sysctl_vals") was backported from 5.17 to 5.15 and 5.10 but not to
5.4. If you agree on the same approach I took for 4.19 (create variable in
kernel/sysctl.c) and send patch for 5.4.

Or, we can backport just to >= 5.10. Cyril and others who merged this obviously
did not consider this important enough to backport. OTOH we have 2 LTP tests
which are testing these:

* sched_rr_get_interval01 tests c7fcb99877f9 (on non-default CONFIG_HZ)
* the other two commits are tested by proc_sched_rt01

Therefore I thought fixing at least 6.* would be good.

Kind regards,
Petr

>  kernel/sched/rt.c | 10 +++++-----
>  kernel/sysctl.c   |  4 ++++
>  2 files changed, 9 insertions(+), 5 deletions(-)