Re: [patch] irqlock patch -G3. [was Re: odd memory corruptionin2.5.27?]

From: Ingo Molnar (mingo@elte.hu)
Date: Wed Jul 24 2002 - 02:54:47 EST


On Wed, 24 Jul 2002, Andrew Morton wrote:

> > Code that relies on
> > cli/sti for atomicity should be pretty rare and limited, there's 1 known
> > case so far where it leads to bugs.
>
> Are you implying that all code which does spin_unlock() inside
> local_irq_disable() needs to be converted to use _raw_spin_unlock()? If
> so then, umm, ugh. I hope that the debug check is working for
> CONFIG_PREEMPT=n.

yes, it works for CONFIG_PREEMT=n as well.

> BTW, what is the situation with spin_unlock_irq[restore]()? Seems that
> these will schedule inside local_irq_disable() quite a lot?

i changed the order in my patch - and there's another valid reason for it:
to slightly reduce the amount of time spent with irqs disabled.

        Ingo

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