Messages in this thread | | | Date | Fri, 18 Aug 2017 11:06:27 +0200 | From | Sebastian Andrzej Siewior <> | Subject | Re: [patch-rt] locking, rwlock-rt: do not save state multiple times in __write_rt_lock() |
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On 2017-08-09 14:04:48 [+0200], Mike Galbraith wrote: > > Save state prior to entering the acquisition loop, otherwise we may > initially see readers, but upon releasing ->wait_lock see none, loop > back around, and having not slept, save TASK_UNINTERRUPTIBLE. > > Signed-off-by_ Mike Galbraith <efault@gmx.de>
applied but
> --- > kernel/locking/rwlock-rt.c | 37 ++++++++++++++++++++----------------- > 1 file changed, 20 insertions(+), 17 deletions(-) > > --- a/kernel/locking/rwlock-rt.c > +++ b/kernel/locking/rwlock-rt.c > @@ -190,30 +190,33 @@ void __sched __write_rt_lock(struct rt_r … > > + for (;;) { > /* Have all readers left the critical region? */ > - if (!atomic_read(&lock->readers)) { > - atomic_set(&lock->readers, WRITER_BIAS); > - raw_spin_lock(&self->pi_lock); > - __set_current_state_no_track(self->saved_state); > - self->saved_state = TASK_RUNNING; > - raw_spin_unlock(&self->pi_lock); > - raw_spin_unlock_irqrestore(&m->wait_lock, flags); > - return;
I kept this part where it is so the diff is smaller.
> - } > + if (!atomic_read(&lock->readers)) > + break; > } > > int __write_rt_trylock(struct rt_rw_lock *lock)
Sebastian
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