Messages in this thread | | | Date | Wed, 24 Jul 2002 09:19:15 +0200 (CEST) | From | Ingo Molnar <> | Subject | Re: [patch] big IRQ lock removal, 2.5.27-G0 |
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On Wed, 24 Jul 2002, Oleg Nesterov wrote:
> > okay - i've fixed irq_exit() once more in -G4 > > found G5, your forgot to add preempt_disable() in irq_exit() > > #define irq_exit() > do { > + preempt_disable(); > preempt_count() -= IRQ_EXIT_OFFSET; > if (!in_interrupt() && softirq_pending(smp_processor_id())) > > Oleg.
nope, it's tricky, check out the define of IRQ_EXIT_OFFSET, it has the plus 1 count added already.
using preempt_disable() has the problem of putting a barrier() between the ++ and the -IRQ_OFFSET, causing one more instruction to be generated.
but there was another (not too critical) bug here - irq_enter() needs to have a barrier() after manipulating the preemption count, irq_exit() needs to have a barrier() before. Fixed in my tree.
Ingo
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