lkml.org 
[lkml]   [2009]   [Apr]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCH 2/3] [BUGFIX] x86/x86_64: fix CPU offlining triggered inactive device IRQ interrruption
    "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


    \
     
     \ /
      Last update: 2009-04-13 20:53    [W:0.027 / U:90.024 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site