Messages in this thread | | | Subject | Re: [PATCH] arm64: fix a migrating irq bug when hotplug cpu | From | Yang Yingliang <> | Date | Tue, 1 Sep 2015 18:02:57 +0800 |
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在 2015/8/31 20:20, Marc Zyngier 写道: > On Sun, 30 Aug 2015 21:15:56 +0800 > Hanjun Guo <hanjun.guo@linaro.org> wrote: > >> On 08/30/2015 02:12 AM, Marc Zyngier wrote: >>> On 2015-08-29 16:12, Jiang Liu wrote: >>>> On 2015/8/29 21:00, Yang Yingliang wrote: >>>>> From: Yang Yingliang <yangyingliang@huawei.com> >>>>> >>>>> When cpu is disabled, all irqs will be migratged to another cpu. >>>>> In some cases, a new affinity is different, it needed to be coppied >>>>> to irq's affinity. But if the type of irq is LPI, it's affinity will >>>>> not be coppied because of irq_set_affinity's return value. >>>>> So copy the affinity, when the return value is IRQ_SET_MASK_OK_DONE. >>>> Hi Yingliang, >>>> If irq_set_affinity callback returns IRQ_SET_MASK_OK_DONE, >>>> it means that irq_set_affinity has copied the new CPU mask to irq >>>> affinity mask. It would be better to change irq_set_affinity for LPI >>>> to follow this rule. >>> >>> The main issue here seems to be that we do not call irq_set_affinity, but >>> that we directly call into the top-level irqchip method, which relies on >>> the core code to do the copy (see irq_do_set_affinity). Too bad. >>> >>> It feels like the arm/arm64 code would probably be better consolidated into >>> kernel/irq/migration.c, which already deals with some of this for x86 >>> and ia64. It would save us the duplication and will make sure we don't >>> miss things next time we add a new return code, as irq_do_set_affinity >>> would handle this properly. >>> >>> Thoughts? >> >> I agree. In arch/arm64/kernel/irq.c the irq migrate code is the same >> as ARM32, and it's duplicate. But this is a bugfix, can we fix it in >> a simple way, and refactor the code later? > > I'm not buying this. > > I really can't see how adding more duplication can be beneficial. It is > not so much that there is duplication between arm and arm64 that > bothers me (as if that was the only thing...). The real issue is that > there is duplication between the arch code and the core code. > > Migrating interrupts is a core code matter, and that's were it should > be handled IMHO. Plus, we're in the merge window, and there is plenty > of time to get this fixed the proper way.
Got it. I'm trying to move the irq migrate code to kernel/irq/migration.c
Regards Yang
> > Thanks, > > M. >
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