Messages in this thread | | | Date | Tue, 5 May 2015 12:42:44 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH] sched: Handle priority boosted tasks proper in setscheduler() |
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On Tue, 5 May 2015 18:31:20 +0200 (CEST) Thomas Gleixner <tglx@linutronix.de> wrote:
> On Tue, 5 May 2015, Steven Rostedt wrote: > > I got pulled onto other things so I never finished it, but one thing > > that worried me about this fix is this: > > > > T1 - FIFO policy (prio = 10) > > lock(rtmutex); > > > > T2 (prio = 20) > > lock(rtmutex) > > boost T1 (prio = 20) > > > > TI (prio = 20) > > sys_sched_setscheduler(prio = 30) > > TI (prio = 30) > > > > T1 (prio = 30) > > sys_sched_setscheduler(SCHED_OTHER) > > new_effective_prio = 20, oldprio = 30 > > > > Before the code stopped at the rt_mutex_check_prio(), but now it > > continues. Will having the policy change cause problems here? > > No, because it stays effective in the FIFO domain. >
Ah, the policy passed in isn't used, so we are safe. But, but I also found that we still call __setscheduler(), which does:
p->prio = normal_prio();
Isn't that going to null out the boosting?
-- Steve
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