Re: [Priority Inheritance] SCHED_FIFO or SCHED_RR?

[Tadeus (Eus) Prastowo]

Anyone familiar with the Linux scheduler, please?

On Wed, Sep 28, 2011 at 1:06 AM, Tadeus (Eus) Prastowo
<0x657573@xxxxxxxxxxxxxx> wrote:
> Hi!
>
> When a SCHED_RR task with RT priority X blocks on a
> priority-inheriting mutex held by a SCHED_NORMAL task with nice value
> Y, RT-Mutex code will change the SCHED_NORMAL task priority to that of
> the SCHED_RR task and based on the new priority, will change the
> scheduling class too. But, each task retains its own scheduling
> policy.
>
> This means that the task inheriting the SCHED_RR priority will be
> scheduled using SCHED_FIFO policy because task_tick_rt does not
> enforce the SCHED_RR time slice when the task policy is not SCHED_RR.
>
> Why should a SCHED_NORMAL task inheriting the priority of a SCHED_RR
> task get the privilege of SCHED_FIFO task for running as long as it
> wishes even when the task giving the inheritance does not have such
> privilege?
>
> Thank you very much.
>
> Please kindly put me in the CC since I am not subscribed to the list.
>
> --
> Eus
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