Re: [tip:irq/core] irq/x86/io_apic: Fix number of pre-allocated irqs

[Ingo Molnar <mingo@kernel.org>]

* Thomas Gleixner <tglx@linutronix.de> wrote:

> On Tue, 28 May 2013, tip-bot for David Cohen wrote:
> 
> > Commit-ID:  8c956b1b935ec98decb470a6abff8c1f8b28e9f0
> > Gitweb:     http://git.kernel.org/tip/8c956b1b935ec98decb470a6abff8c1f8b28e9f0
> > Author:     David Cohen <david.a.cohen@intel.com>
> > AuthorDate: Tue, 30 Apr 2013 16:20:15 -0700
> > Committer:  Ingo Molnar <mingo@kernel.org>
> > CommitDate: Tue, 28 May 2013 12:01:29 +0200
> > 
> > irq/x86/io_apic: Fix number of pre-allocated irqs
> > 
> > arch_probe_nr_irqs() has a typo when returning number of
> > preallocated irqs. Instead of returning the calculated value, it
> > returns a constant number NR_IRQ_LEGACY.
> 
> That's not a typo. That's on purpose.
> 
> We don't want to allocate a gazillion of interrupt descriptors for
> nothing. The only ones which must be pre-allocated are the legacy
> ones.
> 
> > This patch makes sure the calculated value is returned intead.
> 
> And therefor defeats the whole purpose of sparse irqs.
> 
> I'll zap that commit.

Oops, I had a sneaking suspicion about this change but did not read the 
code far enough - thanks for correcting my brainfart!

Thanks,

	Ingo