Messages in this thread Patch in this message | | | Date | Mon, 19 Sep 2005 11:53:36 +0530 | From | Srivatsa Vaddagiri <> | Subject | Re: PATCH: Fix race in cpu_down (hotplug cpu) |
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On Mon, Sep 19, 2005 at 04:11:11PM +1000, Nigel Cunningham wrote: > > Ok, that makes sense. Nigel, could you confirm which idle routine you are > > using? > > >From dmesg: > > monitor/mwait feature present. > using mwait in idle threads.
Ok, that may explain why __cpu_die is timing out for you! Can you try a (untested, I am afraid) patch on these lines:
--- process.c.org 2005-09-19 11:44:57.000000000 +0530 +++ process.c 2005-09-19 11:48:28.000000000 +0530 @@ -245,16 +245,18 @@ EXPORT_SYMBOL_GPL(cpu_idle_wait); */ static void mwait_idle(void) { + int cpu = raw_smp_processor_id(); + local_irq_enable(); if (!need_resched()) { set_thread_flag(TIF_POLLING_NRFLAG); do { __monitor((void *)¤t_thread_info()->flags, 0, 0); - if (need_resched()) + if (need_resched() || cpu_is_offline(cpu)) break; __mwait(0, 0); - } while (!need_resched()); + } while (!need_resched() || !cpu_is_offline(cpu)); clear_thread_flag(TIF_POLLING_NRFLAG); } }
Other idle routines will need similar fix.
> Ok, but what about default_idle?
default_idle should be fine as it is. IOW it should not cause __cpu_die to timeout.
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Thanks and Regards, Srivatsa Vaddagiri, Linux Technology Center, IBM Software Labs, Bangalore, INDIA - 560017 - 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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