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

Mathieu Desnoyers
2010-01-21T17:07:22Z

* Steven Rostedt (rostedt@goodmis.org) wrote:
> On Thu, 2010-01-21 at 11:22 -0500, Mathieu Desnoyers wrote:
> > * Steven Rostedt (rostedt@goodmis.org) wrote:
>
> > > 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.
>
> If it gets used more often, then we need to consider RT. RT modifies
> spin_lock_irqsave into a standard mutex that does not disable
> interrupts. But if something does:
>
> local_irq_save(flags);
> spin_lock_mb(&lock);
> [...]
>
> Then it will break RT (if lock is to be converted).

Good point !

Mathieu

>
> -- Steve
>
>

--
Mathieu Desnoyers
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