From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932278AbcEXMuX (ORCPT ); Tue, 24 May 2016 08:50:23 -0400 Received: from e19.ny.us.ibm.com ([129.33.205.209]:36634 "EHLO e19.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752838AbcEXMuW (ORCPT ); Tue, 24 May 2016 08:50:22 -0400 X-IBM-Helo: d01dlp02.pok.ibm.com X-IBM-MailFrom: paulmck@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org Date: Tue, 24 May 2016 05:50:18 -0700 From: "Paul E. McKenney" To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, mgalbraith@suse.de, ahh@google.com, bsegall@google.com, torvalds@linux-foundation.org, matt@codeblueprint.co.uk, morten.rasmussen@arm.com, pjt@google.com, pkondeti@infradead.org, tglx@linutronix.de, byungchul.park@lge.com, mingo@kernel.org, rgkernel@gmail.com Subject: Re: Bisection: Lost wakeups from b5179ac70de8 Message-ID: <20160524125018.GT3825@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20160523140410.GA26287@linux.vnet.ibm.com> <20160524090455.GF3192@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160524090455.GF3192@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16052412-0057-0000-0000-000004697BDF X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 24, 2016 at 11:04:55AM +0200, Peter Zijlstra wrote: > On Mon, May 23, 2016 at 07:04:10AM -0700, Paul E. McKenney wrote: > > Hello, Peter, > > > > Current mainline doesn't do well with RCU torture testing, and the > > symptom once again looks like lost wakeups. Thankfully, this time each > > run takes only about an hour, and the false-positive/-negative rate > > is negligible. This means that for the first time ever, "git bisect" > > actually did something useful for me. The first bad commit is: > > > > b5179ac70de8 ("sched/fair: Prepare to fix fairness problems on migration"). > > > > Yeah, we have a patch for that.. I'll go writes a Changelog for it and > put it to sched/urgent. > > See lkml.kernel.org/r/20160523091907.GD15728@worktop.ger.corp.intel.com Thank you, will give it a shot. Thanx, Paul