* Frank Ch. Eigler ([EMAIL PROTECTED]) wrote: > Hi - > > On Thu, Jul 26, 2007 at 11:02:26AM -0400, Mathieu Desnoyers wrote: > > [...] > > > > The problem is also in _stp_print_flush, not *only* in relay code: > > > > void _stp_print_flush (void) > > > > ... > > > > spin_lock(&_stp_print_lock); > > > > spin_unlock(&_stp_print_lock); > > > > > > > > Those will turn into mutexes with -rt. > > > > > > Indeed, > > (Though actually that bug was fixed some time ago.) > > > > > plus systemtap-generated locking code uses rwlocks, > > > local_irq_save/restore or preempt_disable, in various places. Could > > > someone point to a place that spells out what would be more > > > appropriate way of ensuring atomicity while being compatible with -rt? > > > > AFAIK, for your needs either: > > [...] > > - Use per-cpu data with preempt disabling/irq disabling > > As in local_irq_save / preempt_disable? Yes, already done. > > > - Use the original "real" spin locks/rwlocks (raw_*). > > [...] > > It was unclear from the OLS paper whether the spin_lock_irq* family of > functions also had to be moved to the raw forms. >
Yes, you have them to move them too: linux/spinlock.h: #ifdef CONFIG_PREEMPT_RT # define _spin_lock(l) rt_spin_lock(l) # define _spin_lock_nested(l, s) rt_spin_lock_nested(l, s) # define _spin_lock_bh(l) rt_spin_lock(l) # define _spin_lock_irq(l) rt_spin_lock(l) # define _spin_unlock(l) rt_spin_unlock(l) # define _spin_unlock_no_resched(l) rt_spin_unlock(l) # define _spin_unlock_bh(l) rt_spin_unlock(l) # define _spin_unlock_irq(l) rt_spin_unlock(l) # define _spin_unlock_irqrestore(l, f) rt_spin_unlock(l) .. And below, both spin_lock and spin_lock_irqsave use PICK_OP to turn into their _spin_lock_* equivalent, which are both mapped to rt_spin_lock in -rt. Mathieu -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
