From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753655AbZHBUrD (ORCPT ); Sun, 2 Aug 2009 16:47:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753645AbZHBUrC (ORCPT ); Sun, 2 Aug 2009 16:47:02 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:45630 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753636AbZHBUrB (ORCPT ); Sun, 2 Aug 2009 16:47:01 -0400 Date: Sun, 2 Aug 2009 22:46:47 +0200 From: Ingo Molnar To: Andrew Morton Cc: paulmck@linux.vnet.ibm.com, mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, torvalds@linux-foundation.org, tglx@linutronix.de, linux-tip-commits@vger.kernel.org Subject: Re: [tip:core/debug] debug lockups: Improve lockup detection Message-ID: <20090802204647.GC3986@elte.hu> References: <20090802114545.f1520c81.akpm@linux-foundation.org> <20090802192657.GA21882@elte.hu> <20090802123958.cbd497a0.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090802123958.cbd497a0.akpm@linux-foundation.org> User-Agent: Mutt/1.5.18 (2008-05-17) 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=3.2.5 -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 * Andrew Morton wrote: > #ifndef trigger_all_cpu_backtrace > +#ifdef CONFIG_SMP > +#warning This architecture is missing a trigger_all_cpu_backtrace() implementation > +#endif > #define trigger_all_cpu_backtrace() do { } while (0) > #endif I think a better solution will be to make this function return 1 if it generated a backtrace. That way we can fall back to the generic schedule_work based codepath. Albeit the best and cleanest solution would be to implement a workqueue based trigger_all_cpu_backtrace() __weak variant and throw away the workqueue bits from sysrq.c. Ingo