From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932731Ab1BXHM6 (ORCPT ); Thu, 24 Feb 2011 02:12:58 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:43375 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932689Ab1BXHM4 (ORCPT ); Thu, 24 Feb 2011 02:12:56 -0500 Date: Thu, 24 Feb 2011 08:12:37 +0100 From: Ingo Molnar To: Thomas Gleixner Cc: LKML , Linus Torvalds , Andrew Morton , Peter Zijlstra Subject: Re: [patch 0/5] genirq: Forced threaded interrupt handlers Message-ID: <20110224071237.GA7197@elte.hu> References: <20110223231601.613115832@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110223231601.613115832@linutronix.de> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -2.0 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 * Thomas Gleixner wrote: > Some time ago when the threaded interrupt handlers infrastructure was > about to be merged, Andrew asked me where that command line switch was > which magically runs all interrupt handlers and the softirqs in > threads. > > While we were doing that brute force in preempt-rt for quite a while > it took some time to come up with a reasonable non intrusive > implementation for mainline. We also had to find a solution which fits > Linus' recently issued "palatable Trojan horse" requirement (see: > https://lwn.net/Articles/370998/). > > The gift of this patch series is the ability to add "threadirqs" to > the kernel command line and magically (almost) all interrupt handlers > - except those which are explicitely marked IRQF_NO_THREAD - are > confined into threads along with all soft interrupts. > > That allows to enhance the debugability of the kernel as a bug in an > interrupt handler is not necessarily taking the whole machine > down. It's just the particular irq thread which goes into nirwana. Bad > luck if that's the one which is crucial to retrieve the bug report, > but in most cases - yes, I analysed quite a lot of bugzilla reports - > it will be helpful for reporters not to be forced to transcribe the > bug from the screen. Just a quick bike shed painting suggestion: could we please name it anything but 'forced' threaded irqs? Something like 'irqthread debugging' or 'full irqthreads'? Thanks, Ingo