Messages in this thread Patch in this message | | | From | "Tian, Kevin" <> | Date | Sat, 7 May 2011 05:41:02 +0800 | Subject | RE: [PATCH v2 1/2] x86: skip migrating IRQF_PER_CPU irq in fixup_irqs |
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> From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@oracle.com] > Sent: Friday, May 06, 2011 9:58 PM > > On Fri, May 06, 2011 at 02:43:36PM +0800, Tian, Kevin wrote: > > x86: skip migrating IRQF_PER_CPU irq in fixup_irqs > > > > IRQF_PER_CPU marks a irq binding to a specific cpu, and can never be > > moved away from that cpu. So it shouldn't be migrated when fixup irqs > > to offline a cpu. Xen pvops guest is one source using IRQF_PER_CPU > ^- are called > > on a set of virtual interrupts. Previously no error is observed > ^^- was > Which ones? Can you be more specific here of which type of virtual interrupts? > spinlock? timer?
all of them: spinlock, timer, resched, callfunc, ...
> > because Xen event chip silently fails the set_affinity ops, and > > logically IRQF_PER_CPU should be recognized here. > > OK, so what if the set_affinity ops was implemented?
it was implemented: (drivers/xen/event.c, rebind_irq_to_cpu) /* * If this fails, it usually just indicates that we're dealing with a * virq or IPI channel, which don't actually need to be rebound. Ignore * it, but don't do the xenlinux-level rebind in that case. */ if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0) bind_evtchn_to_cpu(evtchn, tcpu); Hypervisor doesn't allow to change affinity for virq and ipi.
Thanks, Kevin
> > > > Signed-off-by: Fengzhe Zhang <fengzhe.zhang@intel.com> > > Signed-off-by: Kevin Tian <kevin.tian@intel.com> > > CC: Thomas Gleixner <tglx@linutronix.de> > > CC: Ingo Molnar <mingo@redhat.com> > > CC: H. Peter Anvin <hpa@zytor.com> > > CC: Ian Campbell <Ian.Campbell@citrix.com> > > CC: Jan Beulich <JBeulich@novell.com> > > > > --- linux-2.6.39-rc6.orig/arch/x86/kernel/irq.c 2011-05-04 > 10:59:13.000000000 +0800 > > +++ linux-2.6.39-rc6/arch/x86/kernel/irq.c 2011-05-06 09:20:25.563963000 > +0800 > > @@ -249,7 +250,7 @@ void fixup_irqs(void) > > > > data = irq_desc_get_irq_data(desc); > > affinity = data->affinity; > > - if (!irq_has_action(irq) || > > + if (!irq_has_action(irq) || irqd_is_per_cpu(data) || > > cpumask_subset(affinity, cpu_online_mask)) { > > raw_spin_unlock(&desc->lock); > > continue; > > -- > > To unsubscribe from this list: send the line "unsubscribe > > linux-kernel" in the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > Please read the FAQ at http://www.tux.org/lkml/
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