Re: [tip:x86/irq] x86: apic: Fix mismerge, add arch_probe_nr_irqs()again

[Ingo Molnar]

* Yinghai Lu <yinghai@xxxxxxxxxx> wrote:

> On 02/26/2010 02:26 AM, tip-bot for Ingo Molnar wrote:
> > Commit-ID:  f6a929eb62ef43cae16ba6d4e2c64b4e430fe7a4
> > Gitweb:     http://git.kernel.org/tip/f6a929eb62ef43cae16ba6d4e2c64b4e430fe7a4
> > Author:     Ingo Molnar <mingo@xxxxxxx>
> > AuthorDate: Fri, 26 Feb 2010 11:17:16 +0100
> > Committer:  Ingo Molnar <mingo@xxxxxxx>
> > CommitDate: Fri, 26 Feb 2010 11:17:16 +0100
> > 
> > x86: apic: Fix mismerge, add arch_probe_nr_irqs() again
> > 
> > Merge commit aef55d4922 mis-merged io_apic.c so we lost the
> > arch_probe_nr_irqs() method.
> > 
> > This caused subtle boot breakages (udev confusion likely
> > due to missing drivers) with certain configs.
> > 
> > Cc: H. Peter Anvin <hpa@xxxxxxxxx>
> > Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
> > LKML-Reference: <20100207210250.GB8256@xxxxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
> > ---
> >  arch/x86/kernel/apic/io_apic.c |   22 ++++++++++++++++++++++
> >  1 files changed, 22 insertions(+), 0 deletions(-)
> > 
> > diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
> > index 527390c..c13ab8f 100644
> > --- a/arch/x86/kernel/apic/io_apic.c
> > +++ b/arch/x86/kernel/apic/io_apic.c
> > @@ -3874,6 +3874,28 @@ void __init probe_nr_irqs_gsi(void)
> >  	printk(KERN_DEBUG "nr_irqs_gsi: %d\n", nr_irqs_gsi);
> >  }
> >  
> > +#ifdef CONFIG_SPARSE_IRQ
> > +int __init arch_probe_nr_irqs(void)
> > +{
> > +	int nr;
> > +
> > +	if (nr_irqs > (NR_VECTORS * nr_cpu_ids))
> > +		nr_irqs = NR_VECTORS * nr_cpu_ids;
> > +
> > +	nr = nr_irqs_gsi + 8 * nr_cpu_ids;
> > +#if defined(CONFIG_PCI_MSI) || defined(CONFIG_HT_IRQ)
> > +	/*
> > +	 * for MSI and HT dyn irq
> > +	 */
> > +	nr += nr_irqs_gsi * 16;
> > +#endif
> > +	if (nr < nr_irqs)
> > +		nr_irqs = nr;
> > +
> > +	return 0;
> > +}
> > +#endif
> > +
> >  static int __io_apic_set_pci_routing(struct device *dev, int irq,
> >  				struct io_apic_irq_attr *irq_attr)
> >  {
> 
> for x86, with radix tree based irq_to_desc(),
> removing arch_probe_nr_irqs is intentional. so we get more irq that could be used.
> 
> wonder if the udev for some of your test system have irq number limitation?

was ancient udev: udev-095-17.fc6.

	Ingo
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