Messages in this thread | | | Subject | Re: [PATCH 2/3] [BUGFIX] x86/x86_64: fix CPU offlining triggered inactive device IRQ interrruption | From | "Pallipadi, Venkatesh" <> | Date | Mon, 13 Apr 2009 10:41:35 -0700 |
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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, Venki
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