Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753945AbZAFRAv (ORCPT ); Tue, 6 Jan 2009 12:00:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751209AbZAFRAj (ORCPT ); Tue, 6 Jan 2009 12:00:39 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:33689 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751194AbZAFRAi (ORCPT ); Tue, 6 Jan 2009 12:00:38 -0500 Date: Tue, 6 Jan 2009 08:59:52 -0800 (PST) From: Linus Torvalds X-X-Sender: torvalds@localhost.localdomain To: Ingo Molnar cc: Peter Zijlstra , Matthew Wilcox , Andi Kleen , Chris Mason , Andrew Morton , linux-kernel@vger.kernel.org, linux-fsdevel , linux-btrfs , Thomas Gleixner , Steven Rostedt , Gregory Haskins , Nick Piggin Subject: Re: [PATCH][RFC]: mutex: adaptive spin In-Reply-To: <20090106165409.GA32608@elte.hu> Message-ID: References: <1230765549.7538.8.camel@think.oraclecorp.com> <87r63ljzox.fsf@basil.nowhere.org> <20090103191706.GA2002@parisc-linux.org> <1231093310.27690.5.camel@twins> <20090104184103.GE2002@parisc-linux.org> <1231242031.11687.97.camel@twins> <20090106121052.GA27232@elte.hu> <20090106165409.GA32608@elte.hu> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 742 Lines: 22 On Tue, 6 Jan 2009, Ingo Molnar wrote: > > So instead of the BUG_ON() we could emit a WARN_ONCE() perhaps, plus not > do any spinning and just block - resulting in an uninterruptible task > (that the user will probably notice) and a scary message in the syslog? > [all in the slowpath] Sure. You could put it in the adaptive function thing, with something like if (WARN_ONCE(waiter == owner)) return 1; which should fall back on the old behavior and do the one-time warning. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/