Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: [patch 03/63] sched: Prepare for RT sleeping spin/rwlocks | Date | Tue, 03 Aug 2021 22:11:17 +0200 |
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On Tue, Aug 03 2021 at 16:51, Peter Zijlstra wrote: > On Tue, Aug 03, 2021 at 04:04:07PM +0200, Thomas Gleixner wrote: >> On Tue, Aug 03 2021 at 11:48, Peter Zijlstra wrote: >> >> > On Sun, Aug 01, 2021 at 05:30:06PM +0200, Mike Galbraith wrote: >> >> On Fri, 2021-07-30 at 15:50 +0200, Thomas Gleixner wrote: >> >> > >> >> > --- a/include/linux/sched.h >> >> > +++ b/include/linux/sched.h >> >> > @@ -155,6 +155,27 @@ struct task_group; >> >> > WRITE_ONCE(current->__state, (state_value)); \ >> >> > raw_spin_unlock_irqrestore(¤t->pi_lock, flags); \ >> >> > } while (0) >> >> > + >> >> > + >> >> > +#define current_save_and_set_rtlock_wait_state() \ >> >> > + do { \ >> >> > + raw_spin_lock(¤t->pi_lock); \ >> > >> > That wants to be irqsafe methinks, I realize this is PREEMPT_RT only and >> > there the _irqfoo crap is a no-op so this doesn't really matter one way >> > or the other, but still, taking PI lock without IRQ disable makes my >> > head go BUG-BUG-BUG :-) >> >> Actually the rule to lock PI lock irqsave still persists on RT, but this >> has to be called with interrupts disabled (rtmutex::wait_lock is held), >> so adding a lockdep_assert_irqs_disable() might be good enough to spare >> the extra save/restore. Hmm? > > Works for me.. and yes, duh, raw_.
And the lockdep_assert_irqs_disabled() is redundant as well because if raw_spin_lock(¤t->pi_lock) is invoked with interrupts enabled lockdep will yell too. But, yes it makes it more explicit.
Thanks,
tglx
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