Messages in this thread | | | Date | Thu, 10 Jul 2008 22:41:06 -0700 | From | Suresh Siddha <> | Subject | Re: [patch 11/26] x64, x2apic/intr-remap: generic irq migration support from process context |
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On Thu, Jul 10, 2008 at 04:08:03PM -0700, Eric W. Biederman wrote: > Suresh Siddha <suresh.b.siddha@intel.com> writes: > > > Generic infrastructure for migrating the irq from the process context in the > > presence of CONFIG_GENERIC_PENDING_IRQ. > > > > This will be used later for migrating irq in the presence of > > interrupt-remapping. > > Why the API difference between IRQ_MOVE_PCNTXT set affinity handlers and > !CONFIG_GENERIC_PENDING_IRQ handlers?
You are referring to desc->lock portion?
Two reasons:
a. Other code in CONFIG_GENERIC_PENDING_IRQ, assuming that desc->lock is held while calling set_affinity. like fixup_irqs(). Just wanted to be same across the board.
b. for level triggered, we still touch irq_desc and set IRQ_MOVE_PENDING, when we fail to move the irq (if there is already some level triggered interrupt happening in parallel). while, we can acquire the lock inside the set_affinity, I thought this simplifies things.
> > > > #ifdef CONFIG_GENERIC_PENDING_IRQ > > - set_pending_irq(irq, cpumask); > > + if (desc->status & IRQ_MOVE_PCNTXT) { > > + unsigned long flags; > > + > > + spin_lock_irqsave(&desc->lock, flags); > > + desc->chip->set_affinity(irq, cpumask); > > + spin_unlock_irqrestore(&desc->lock, flags); > > + } else > > + set_pending_irq(irq, cpumask); > > #else > > desc->affinity = cpumask; > > desc->chip->set_affinity(irq, cpumask); > > > > --
thanks, suresh
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