From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753151AbcDPAba (ORCPT ); Fri, 15 Apr 2016 20:31:30 -0400 Received: from e33.co.us.ibm.com ([32.97.110.151]:39058 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751676AbcDPAb2 (ORCPT ); Fri, 15 Apr 2016 20:31:28 -0400 X-IBM-Helo: d03dlp03.boulder.ibm.com X-IBM-MailFrom: paulmck@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org Date: Fri, 15 Apr 2016 17:31:53 -0700 From: "Paul E. McKenney" To: "Shi, Yang" Cc: linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org Subject: Re: [PATCH] locktorture: make verbose writable and control stats print Message-ID: <20160416003153.GE3687@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <1460752091-28023-1-git-send-email-yang.shi@linaro.org> <20160415232613.GC3687@linux.vnet.ibm.com> <57117D1C.3080109@linaro.org> <20160416000930.GD3687@linux.vnet.ibm.com> <5711850F.3000709@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5711850F.3000709@linaro.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16041600-0009-0000-0000-00001E44291D Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 15, 2016 at 05:19:27PM -0700, Shi, Yang wrote: > On 4/15/2016 5:09 PM, Paul E. McKenney wrote: > >On Fri, Apr 15, 2016 at 04:45:32PM -0700, Shi, Yang wrote: > >>On 4/15/2016 4:26 PM, Paul E. McKenney wrote: > >>>On Fri, Apr 15, 2016 at 01:28:11PM -0700, Yang Shi wrote: > >>>>When building locktorture test into kernel image, it keeps printing out > >>>>stats information even though there is no lock type specified. > >>>> > >>>>There is already verbose parameter to control print, but it is read-only, > >>>>so it can't be changed at runtime. Make verbose read-write and control > >>>>stats print. > >>>> > >>>>Signed-off-by: Yang Shi > >>> > >>>Interesting change! > >>> > >>>But just out of curiosity, when you boot with locktorture built in, > >>>do you specify the shutdown_secs boot parameter? If so, another > >> > >>No, just use the default value, which is 0 for shutdown_secs. > >> > >>>approach would be to shutdown immediately upon detecting an error > >>>during initialization. > >> > >>In my case, it looks there is not error involved. > > > >You said that there is no lock type specified, but that should mean that > >the default ("spin_lock") is chosen. If so, I would expect it to just > > Yes, spin_lock is chosen by default. > > >do the test, at least if locktorture.torture_runnable has been set. > > But, the default value of torture_runnable is 0. And, it is readonly > parameter too. This prevents torture from running if it is built > into kernel instead of module. You can specify locktorture.torture_runnable on the kernel command line. That way, you can build a single kernel and decide at boot time whether or not you are going to torture locking. > Actually, I'm confused why there is not LOCK_TORTURE_TEST_RUNNABLE > Kconfig like RCU torture? Because there is much more resistance to Kconfig variables than there used to be. ;-) Thanx, Paul > Thanks, > Yang > > > > >Either way, the usual way to make locktorture shut up would be to boot > >with locktorture.stat_interval=0. > > > >>>If not, I would like to know more about your use case. > >> > >>In my test, I just built locktorture test into kernel instead of a > >>module then check how it behaves, no specific purpose. > >> > >>It sounds like not a normal approach to use it. > > > >Agreed, I do believe that this is a case of "working as designed". > > > > Thanx, Paul > > >