From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754536Ab1CUVk6 (ORCPT ); Mon, 21 Mar 2011 17:40:58 -0400 Received: from www.linutronix.de ([62.245.132.108]:40715 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754378Ab1CUVk4 (ORCPT ); Mon, 21 Mar 2011 17:40:56 -0400 X-Greylist: delayed 1639 seconds by postgrey-1.27 at vger.kernel.org; Mon, 21 Mar 2011 17:40:55 EDT Date: Mon, 21 Mar 2011 22:13:22 +0100 (CET) From: Thomas Gleixner To: David Daney cc: linux-mips@linux-mips.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 1/2] genirq: Add chip hooks for taking CPUs on/off line. In-Reply-To: <4D879869.8060405@caviumnetworks.com> Message-ID: References: <1300484916-11133-1-git-send-email-ddaney@caviumnetworks.com> <1300484916-11133-2-git-send-email-ddaney@caviumnetworks.com> <4D879869.8060405@caviumnetworks.com> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 21 Mar 2011, David Daney wrote: > On 03/19/2011 01:51 PM, Thomas Gleixner wrote: > > On Fri, 18 Mar 2011, David Daney wrote: > > > --- a/include/linux/irqdesc.h > > > +++ b/include/linux/irqdesc.h > > > @@ -178,6 +178,12 @@ static inline int irq_has_action(unsigned int irq) > > > return desc->action != NULL; > > > } > > > > > > +/* Test to see if the irq is currently enabled */ > > > +static inline int irq_desc_is_enabled(struct irq_desc *desc) > > > +{ > > > + return desc->depth == 0; > > > +} > > > > That want's to go into kernel/irq/internal.h > > I think I need to use this in my irq_chip.irq_unmask method. > > Consider this: > > > CPU0 CPU1 > handle_level_irq > lock > mask > handle_irq_event > unlock > . > . disable_irq > . > lock > unmask > unlock handle level irq does: if (!(desc->istate & (IRQS_DISABLED | IRQS_ONESHOT))) unmask_irq(desc); So it does not call unmask. > I need to know in my .unmask method if the interrupt has been disabled. If it > has, I will not re-enable (unmask)it. It wont be called :) > > > > > #ifndef CONFIG_GENERIC_HARDIRQS_NO_COMPAT > > > static inline int irq_balancing_disabled(unsigned int irq) > > > { > > > diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c > > > index c9c0601..40736f7 100644 > > > --- a/kernel/irq/chip.c > > > +++ b/kernel/irq/chip.c > > > @@ -689,3 +689,38 @@ void irq_modify_status(unsigned int irq, unsigned > > > long clr, unsigned long set) > > > > > > irq_put_desc_unlock(desc, flags); > > > } > > > + > > > +void irq_cpu_online(unsigned int irq) > > > > Odd function name. It does not reflect that this is for per cpu > > interrupts. So something like irq_xxx_per_cpu_irq(irq) > > might be a bit more descriptive. > > I am using it for per cpu interrupts, but I didn't want to impose that policy > on others. I can't imagine any other purpose for that. > > Though one question remains: should we just iterate over the irq space > > and call the online/offline callbacks when available instead of having > > the arch code do the iteration. > > > > That would be good I think, especially for sparse irqs. > > In the case of the CPU going offline, the .irq_cpu_offline() may need to > adjust the affinity so that the irq no longer has affinity for the off-lined > CPU. > > This is something needed even for non-per-cpu interrupts. Also I would need a > way to call irq_set_affinity() while holding the desc->lock. Hmm. The offline fixup_irq() code is arch specific and usually calls desc->irq_data.chip->irq_set_affinity under desc->lock. I have not yet found an arch independent way to do that. Any ideas welcome. Thanks, tglx