From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933131AbdBHJnR (ORCPT ); Wed, 8 Feb 2017 04:43:17 -0500 Received: from merlin.infradead.org ([205.233.59.134]:49040 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753934AbdBHJ1d (ORCPT ); Wed, 8 Feb 2017 04:27:33 -0500 Date: Wed, 8 Feb 2017 10:27:26 +0100 From: Peter Zijlstra To: "Paul E. McKenney" Cc: Waiman Long , Ingo Molnar , Ingo Molnar , linux-kernel@vger.kernel.org, Linus Torvalds , Thomas Gleixner , Andrew Morton Subject: Re: [PATCH v3 0/3] locking/spinlock_debug: Change it to a mostly fair lock Message-ID: <20170208092726.GV6515@twins.programming.kicks-ass.net> References: <1486044929-7244-1-git-send-email-longman@redhat.com> <20170207084553.GW6500@twins.programming.kicks-ass.net> <20170207094816.GC9829@gmail.com> <20170207195308.GY30506@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170207195308.GY30506@linux.vnet.ibm.com> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 07, 2017 at 11:53:08AM -0800, Paul E. McKenney wrote: > My usual question is "how often does the spinlock_debug code find a > problem that would be hard to find otherwise?" Probably unanswerable > given the nature of Linux-kernel development, but I figured I would ask > anyway. ;-) So I've not found it useful in many years, and quite to the contrary, its proven prone to generate false positives because the lock timeout gets hit because of various reasons. But that's just me of course..