Re: [PATCH -rt] revert bh_lru_lock() to preempt_disable()

From: Ingo Molnar
Date: Wed May 03 2006 - 16:56:06 EST



* Daniel Walker <dwalker@xxxxxxxxxx> wrote:

> > i agree that this is a problem, but the fix is incorrect. What would be
> > the right approach is to convert the PER_CPU bh_lrus to PER_CPU_LOCKED,
> > and to use the appropriate primitives to use them. That automatically
> > makes this code rt-safe. (it isnt right now)
>
> Hmm, in UP it should be safe to access per cpu data under either a
> preempt_disable or local_irq_disable . I'm not sure how RT changes
> that .. Is there some other part of the code that isn't rt-safe, which
> I've overlooked ?

hm, you are right - that code can be in a preempt-off section. I've
applied your patch.

Ingo
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