Messages in this thread | | | Date | Fri, 3 Nov 2023 08:11:40 +0100 | From | Juri Lelli <> | Subject | Re: [RFC PATCH 1/3] sched/core: Provide a method to check if a task is PI-boosted. |
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On 02/11/23 17:03, Sebastian Andrzej Siewior wrote: > On 2023-11-02 10:30:50 [+0100], Juri Lelli wrote: > > Hi, > Hi, > > > Apologies for noticing only now, but I believe this is still part of the > > 6.6-rt patches and I've got the below question to ask. > > I'm not sure if we want this. I do have an alternative solution in the > meantime.
Ah, OK. Guess what below is moot then. :) Will be watching for the alternative solution to show up. > > > > --- a/kernel/sched/core.c > > > +++ b/kernel/sched/core.c > > > @@ -8886,6 +8886,21 @@ static inline void preempt_dynamic_init(void) { } > > > > > > #endif /* #ifdef CONFIG_PREEMPT_DYNAMIC */ > > > > > > +/* > > > + * task_is_pi_boosted - Check if task has been PI boosted. > > > + * @p: Task to check. > > > + * > > > + * Return true if task is subject to priority inheritance. > > > + */ > > > +bool task_is_pi_boosted(const struct task_struct *p) > > > +{ > > > + int prio = p->prio; > > > + > > > + if (!rt_prio(prio)) > > > + return false; > > > + return prio != p->normal_prio; > > > > Does this need to also take DEADLINE tasks into consideration? We don't > > change priority when they are boosted, only pi_se changes (please check > > is_dl_boosted()). > > If we want this, then probably yes. > Isn't task_struct::prio for the DL (boosted) task set to 0? While the RT > priority go from 1…MAX_RT_PRIO - 1.
But then we can also have DL on DL boosting and in this case only the pi_se changes while prio stays the same. But, again, looks like this is moot anyway.
Thanks! Juri
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