Re: [RFC PATCH] introduce sys_membarrier(): process-wide memory barrier (v5)

Mathieu Desnoyers
2010-01-21T16:22:52Z

* Steven Rostedt (rostedt@goodmis.org) wrote:
> On Thu, 2010-01-21 at 11:07 -0500, Mathieu Desnoyers wrote:
> > * Peter Zijlstra (peterz@infradead.org) wrote:
>
> > We can even create a generic fallback with the following kind of code in
> > the meantime:
> >
> > static inline void spin_lock_mb(spinlock_t *lock)
> > {
> > spin_lock(&lock);
>
> That would be spin_lock(lock);
>
> > smp_mb();
> > }
> >
> > static inline void spin_unlock_mb(spinlock_t *lock)
> > {
> > smp_mb();
> > spin_unlock(&lock);
>
> and spin_unlock(lock);
>
> ;-)

Oh, right. I should think of integrating a compiler in my mail client ;)

>
> > }
> >
> > How does that sound ?
>
> You may also need spin_lock_irqsave, et al. variants too.

Yep, or we simply use the local_irq_save/restore separately. That could
be a good idea given that only few specialized sites are affected.

Thanks,

Mathieu

>
> -- Steve
>
>

--
Mathieu Desnoyers
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