From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gleixner Subject: Re: [patch 2/2] genirq: Remove IRQF_DISABLED from core code Date: Fri, 26 Mar 2010 12:19:01 +0100 (CET) Message-ID: References: <20100326000325.917127328@linutronix.de> <20100326000405.991244690@linutronix.de> <20100326062054.GW20695@one.firstfloor.org> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: In-Reply-To: <20100326062054.GW20695@one.firstfloor.org> Sender: linux-kernel-owner@vger.kernel.org To: Andi Kleen Cc: Linus Torvalds , LKML , linux-arch@vger.kernel.org, Andrew Morton , Ingo Molnar , Peter Zijlstra , Alan Cox , David Miller , Greg Kroah-Hartman , Arnaldo Carvalho de Melo List-Id: linux-arch.vger.kernel.org On Fri, 26 Mar 2010, Andi Kleen wrote: > On Fri, Mar 26, 2010 at 12:06:55AM -0000, Thomas Gleixner wrote: > > Remove all code which is related to IRQF_DISABLED from the core kernel > > code. IRQF_DISABLED still exists as a flag, but becomes a NOOP and > > will be removed after a grace period. That way we can easily revert to > > the previous behaviour by just restoring the core code. > > Perhaps I'm dense but it's not fully clear to me why is suddenly safe to use > the behaviour of this flags on shared interrupts when it wasn't before? The shared handlers cannot guarantee to run one with irqs enabled and the other with irqs disabled. That's all. There is absolutely no reason why we would need interrupts enabled to process the shared handler chain. Thanks, tglx From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from www.tglx.de ([62.245.132.106]:57009 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753352Ab0CZLUD (ORCPT ); Fri, 26 Mar 2010 07:20:03 -0400 Date: Fri, 26 Mar 2010 12:19:01 +0100 (CET) From: Thomas Gleixner Subject: Re: [patch 2/2] genirq: Remove IRQF_DISABLED from core code In-Reply-To: <20100326062054.GW20695@one.firstfloor.org> Message-ID: References: <20100326000325.917127328@linutronix.de> <20100326000405.991244690@linutronix.de> <20100326062054.GW20695@one.firstfloor.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-arch-owner@vger.kernel.org List-ID: To: Andi Kleen Cc: Linus Torvalds , LKML , linux-arch@vger.kernel.org, Andrew Morton , Ingo Molnar , Peter Zijlstra , Alan Cox , David Miller , Greg Kroah-Hartman , Arnaldo Carvalho de Melo Message-ID: <20100326111901.Su6kzrKowBZdx_ePjcvzTslhvdy1KAx6kdD4p28IvRw@z> On Fri, 26 Mar 2010, Andi Kleen wrote: > On Fri, Mar 26, 2010 at 12:06:55AM -0000, Thomas Gleixner wrote: > > Remove all code which is related to IRQF_DISABLED from the core kernel > > code. IRQF_DISABLED still exists as a flag, but becomes a NOOP and > > will be removed after a grace period. That way we can easily revert to > > the previous behaviour by just restoring the core code. > > Perhaps I'm dense but it's not fully clear to me why is suddenly safe to use > the behaviour of this flags on shared interrupts when it wasn't before? The shared handlers cannot guarantee to run one with irqs enabled and the other with irqs disabled. That's all. There is absolutely no reason why we would need interrupts enabled to process the shared handler chain. Thanks, tglx