Messages in this thread | | | Date | Thu, 29 Aug 2002 11:24:21 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] misc. kernel preemption bits |
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Robert Love wrote: > > ... > - we have a debug check in preempt_schedule that, even > on detecting a schedule with irqs disabled, still goes > ahead and reschedules. We should return. (me) >
OK, but that warning will still come out of the mess in mm/slab.c.
Reminder:
CPU0: CPU1: local_irq_disable(); resched_task(task on CPU0) spin_lock(); ... p->need_resched = 1; spin_unlock(); // reschedules local_irq_enable();
There is one code path in slab which fixes this with _raw_spin_unlock() and a subsequent preempt_disable(), but there are quite a lot of other code paths which need the same treatment. Fixing them is messy.
So unless you guys hit me with a brick, I'll create:
#ifdef CONFIG_SMP #define preempt_disable_irqsave(flags) do { preempt_disable(); local_irq_save(flags); } while (0) #define preempt_enable_irqrestore(flags) do { local_irq_restore(flags); preempt_enable(); } while (0) #else #define preempt_disable_irqsave(flags) do { local_irq_save(flags); } while (0) #define preempt_enable_irqrestore(flags) do { local_irq_restore(flags); } while (0) #endif
and use that in slab. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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