Re: [PATCH 20/62] sparc: irq: Remove IRQF_DISABLED

Yong Zhang
2011-09-08T03:15:46Z

On Wed, Sep 07, 2011 at 08:43:56PM +0200, Thomas Gleixner wrote:
> On Wed, 7 Sep 2011, David Miller wrote:
>
> > From: Thomas Gleixner <tglx@linutronix.de>
> > Date: Wed, 7 Sep 2011 19:57:21 +0200 (CEST)
> >
> > > On Wed, 7 Sep 2011, David Miller wrote:
> > >> From: Thomas Gleixner <tglx@linutronix.de>
> > >> Date: Wed, 7 Sep 2011 19:33:52 +0200 (CEST)
> > >>
> > >> We had big problems when openning thousands of virtual network
> > >> devices, each with their own unique IRQ, and pointed all at the same
> > >> cpu, and we'd get IRQ stack overflows.
> > >>
> > >> See commit c58543c869606532c2382f027d6466f4672ea756
> > >>
> > >> So this change to make IRQF_DISABLED a nop has reintroduced this bug.
> > >
> > > See commit e58aa3d2d0cc01ad8d6f7f640a0670433f794922
> > >
> > > We run ALL interrupt handlers with interrupts disabled for that reason
> > > and we even check and yell when an interrupt handler returns with
> > > interrupts enabled. That's why IRQF_DISABLED became meaningless.
> >
> > Awesome.
> >
> > Can I politely ask that a reference to that commit and something like
> > your paragraph here explaining things is added to these IRQF_DISABLED
> > removal patches?

I should have shown more in the commit log, thus this kind of misleading
could be avoided. Sorry Dave.

>
> That's a good idea. I'll let sed loose on the changelogs when I pick
> them up.

Thanks Thomas.

Yong