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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This archive was generated by hypermail 2b29 : Tue Jul 30 2002 - 14:00:15 EST