Messages in this thread | | | Date | Fri, 3 Sep 2021 12:55:16 +0200 | From | Sebastian Andrzej Siewior <> | Subject | Re: [PATCH 2/2] locking/rwbase_rt: Lockless reader waking up a writer |
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On 2021-09-01 15:28:25 [-0700], Davidlohr Bueso wrote: > diff --git a/kernel/locking/rwbase_rt.c b/kernel/locking/rwbase_rt.c > index 4ba15088e640..3444bc709973 100644 > --- a/kernel/locking/rwbase_rt.c > +++ b/kernel/locking/rwbase_rt.c > @@ -141,6 +141,7 @@ static void __sched __rwbase_read_unlock(struct rwbase_rt *rwb, > { > struct rt_mutex_base *rtm = &rwb->rtmutex; > struct task_struct *owner; > + DEFINE_WAKE_Q(wake_q); > > raw_spin_lock_irq(&rtm->wait_lock); > /* > @@ -151,9 +152,10 @@ static void __sched __rwbase_read_unlock(struct rwbase_rt *rwb, > */ > owner = rt_mutex_owner(rtm); > if (owner) > - wake_up_state(owner, state); > + wake_q_add(&wake_q, owner); > > raw_spin_unlock_irq(&rtm->wait_lock); > + wake_up_q_state(&wake_q, state); > }
You keep the same wake_q in task_struct. Don't you miss states/wake ups if a task needs both wakes? one for TASK_NORMAL and one for TASK_UNINTERRUPTIBLE? Side note: This wake up happens in an-IRQ off region. So there no PI-boosting dance around as it would be the case with a sleeping lock.
Sebastian
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