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

Steven Rostedt
2010-01-21T16:32:24Z

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).

-- Steve