From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ipmailnode02.adl6.internode.on.net ([150.101.137.148]:61291 "EHLO ipmailnode02.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751173AbdINAk6 (ORCPT ); Wed, 13 Sep 2017 20:40:58 -0400 Date: Thu, 14 Sep 2017 10:40:38 +1000 From: Dave Chinner Subject: Re: [PATCH] xfs: add regression test for DAX mount option usage Message-ID: <20170914004038.GZ10621@dastard> References: <20170908152805.GA16646@linux.intel.com> <20170908212153.14880-1-ross.zwisler@linux.intel.com> <20170912064411.GR10621@dastard> <20170912153820.GA5000@linux.intel.com> <20170912234729.GW10621@dastard> <20170913144215.GA12395@linux.intel.com> <20170913220108.GX10621@dastard> <20170913233438.GY10621@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Dan Williams Cc: Ross Zwisler , Jan Kara , Eryu Guan , "linux-nvdimm@lists.01.org" , "Darrick J. Wong" , fstests@vger.kernel.org, linux-xfs@vger.kernel.org, Christoph Hellwig On Wed, Sep 13, 2017 at 05:28:39PM -0700, Dan Williams wrote: > On Wed, Sep 13, 2017 at 4:34 PM, Dave Chinner wrote: > > /me shrugs > > > > I just don't like the concept of using tracepoints to as a > > definitive diagnostic test for something working because it'll break > > when the kernel implementation and tracepoints change. So while we > > can probe for perf being present, we can't probe whether the > > tracepoint we need behaves as the test expects it to... > > That concern makes sense. > > We handle that it a crude way in the libnvdimm unit tests by hard > coding a required minimum kernel version and rolling a test forward to > depend on a new kernel when assumptions about the kernel-internals > change. The tests also inject out-of-tree kernel modules that let us > go after specific kernel internal behavior. With this approach we > don't end up creating userspace ABI since the test explicitly loads > out-of-tree modules. That's horrible. OT, but how are distros or anyone backporting libnvdimm fixes and features supposed to test their kernels work correctly with such a test harness? Cheers, Dave. -- Dave Chinner david@fromorbit.com