From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760295AbYGRRWv (ORCPT ); Fri, 18 Jul 2008 13:22:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756166AbYGRRWm (ORCPT ); Fri, 18 Jul 2008 13:22:42 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:47190 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755937AbYGRRWl (ORCPT ); Fri, 18 Jul 2008 13:22:41 -0400 Date: Fri, 18 Jul 2008 19:22:31 +0200 From: Ingo Molnar To: "Eric W. Biederman" Cc: "Thomas Gleixner Gleixner" , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Enable polling for disabled screaming irqs Message-ID: <20080718172231.GM6875@elte.hu> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Eric W. Biederman wrote: > When we disable a screaming irq we never see it again. If the irq > line is shared or if the driver half works this is a real pain. So > periodically poll the handlers for screaming interrupts. > > I use a timer instead of the classic irq poll technique of working off > the timer interrupt because when we use the local apic timers > note_interrupt is never called (bug?). Further on a system with > dynamic ticks the timer interrupt might not even fire unless there is > a timer telling it it needs to. > > I forced this case on my test system with an e1000 nic and my ssh > session remained responsive despite the interrupt handler only being > called every 10th of a second. very nice idea! I have applied your patch to tip/genirq, thanks Eric. We need more kernel robustness features like this. Ingo