Re: [tip:sched/core] sched/core: Document that RT task priorities are 1...99

[John Ogness]

On 2019-04-16, Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> wrote:
> On 2019-04-16 11:36:34 [+0200], Peter Zijlstra wrote:
>> On Tue, Apr 16, 2019 at 01:13:11AM -0700, tip-bot for Sebastian Andrzej Siewior wrote:
>> > Commit-ID:  37a8f8590f307db8f8cfa62dfd82b3fc0978607c
>> > Gitweb:     https://git.kernel.org/tip/37a8f8590f307db8f8cfa62dfd82b3fc0978607c
>> > Author:     Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
>> > AuthorDate: Wed, 3 Apr 2019 23:08:21 +0200
>> > Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
>> > CommitDate: Tue, 16 Apr 2019 10:06:08 +0200
>> > 
>> > sched/core: Document that RT task priorities are 1...99
>> > 
>> > John identified three files which claim that RT task priorities start at
>> > zero. As far as I understand, 0 is used for DL and has nothing to do
>> > wihich RT priorities as identified by the RT policy.
>> 
>> DL is -1, 0 is still very much FIFO/FF
>
> but it can't be set. The lowest we can set is 1. Is this a bug then?

I think it is important to clarify if you are talking about userspace or
kernel. They are different. For userspace 1(low)-99(high) is
allowed. For kernel 0(high)-98(low) is used.

John Ogness