Messages in this thread | | | From | (Eric W. Biederman) | Date | Mon, 13 Apr 2009 11:50:20 -0700 | Subject | Re: [PATCH 2/3] [BUGFIX] x86/x86_64: fix CPU offlining triggered inactive device IRQ interrruption |
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"Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com> writes:
> On Sat, 2009-04-11 at 04:01 -0700, Eric W. Biederman wrote: >> Yinghai Lu <yhlu.kernel@gmail.com> writes: >> >> > commit 932775a4ab622e3c99bd59f14cc7d96722f79501 >> > Author: venkatesh.pallipadi@intel.com <venkatesh.pallipadi@intel.com> >> > Date: Fri Sep 5 18:02:15 2008 -0700 >> > >> > x86: HPET_MSI change IRQ affinity in process context when it is disabled >> > >> > Change the IRQ affinity in the process context when the IRQ is disabled. >> > >> > Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> >> > Signed-off-by: Shaohua Li <shaohua.li@intel.com> >> > Signed-off-by: Ingo Molnar <mingo@elte.hu> >> > >> > diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c >> > index ddc9568..ad2ce72 100644 >> > --- a/kernel/irq/manage.c >> > +++ b/kernel/irq/manage.c >> > @@ -87,10 +87,11 @@ int irq_set_affinity(unsigned int irq, cpumask_t cpumask) >> > return -EINVAL; >> > >> > #ifdef CONFIG_GENERIC_PENDING_IRQ >> > - if (desc->status & IRQ_MOVE_PCNTXT) { >> > + if (desc->status & IRQ_MOVE_PCNTXT || desc->status & IRQ_DISABLED) { >> > unsigned long flags; >> > >> > spin_lock_irqsave(&desc->lock, flags); >> > + desc->affinity = cpumask; >> > desc->chip->set_affinity(irq, cpumask); >> > spin_unlock_irqrestore(&desc->lock, flags); >> > } else >> >> If the goal is moving MSIs, we should modify the msi code to be safe >> in process context and to set IRQ_MOVE_PCNTXT. >> >> The only reason we migrate MSIs in interrupt context today is that there >> wasn't infrastructure for support migration both in interrupt context >> and outside of it. >> > > Yes. The idea here was to force the MSI migration to happen in process > context. One of the patches in the series did > > disable_irq(dev->irq); > irq_set_affinity(dev->irq, cpumask_of(dev->cpu)); > enable_irq(dev->irq); > > with the above patch adding irq/manage code check for interrupt disabled > and moving the interrupt in process context. > > IIRC, there was no IRQ_MOVE_PCNTXT when we were developing this HPET > code and we ended up having this ugly hack. IRQ_MOVE_PCNTXT was there > when we eventually submitted the patch upstream. But, looks like I did a > blind rebasing instead of using IRQ_MOVE_PCNTXT in hpet MSI code. That > was my fault. Will send a patch to fix this ugliness.
Thanks.
Eric
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