From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754785AbdKCHfN (ORCPT ); Fri, 3 Nov 2017 03:35:13 -0400 Received: from mail5.windriver.com ([192.103.53.11]:47798 "EHLO mail5.wrs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752777AbdKCHfM (ORCPT ); Fri, 3 Nov 2017 03:35:12 -0400 Subject: Re: [PATCH] selftests: remove obsolete kconfig fragment for cpu-hotplug To: Sumit Semwal References: <1508292623-8479-1-git-send-email-lei.yang@windriver.com> <33c654fe-7d48-15e4-ee3b-1dba7dd41dd4@osg.samsung.com> <35526695-658f-377e-e551-7f70658e3558@windriver.com> CC: Shuah Khan , Thomas Gleixner , "open list:KERNEL SELFTEST FRAMEWORK" , LKML , Greg Kroah-Hartman , Shuah Khan From: lyang0 Message-ID: Date: Fri, 3 Nov 2017 15:34:31 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [128.224.163.162] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2017年11月03日 11:55, Sumit Semwal wrote: > Hello Lei, > > On 2 November 2017 at 07:43, lyang0 wrote: >> >> On 2017年11月02日 06:59, Shuah Khan wrote: >>> On 11/01/2017 04:52 PM, Thomas Gleixner wrote: >>>> On Wed, 1 Nov 2017, Shuah Khan wrote: >>>>> On 10/17/2017 08:10 PM, lei.yang@windriver.com wrote: >>>>>> From: Lei Yang >>>>>> >>>>>> Kconfig CONFIG_CPU_NOTIFIER_ERROR_INJECT has been removed since kernel >>>>>> 4.10 >>>>>> check commit: >>>>>> commit 530e9b76ae8f863dfdef4a6ad0b38613d32e8c3f >>>>>> Author: Thomas Gleixner >>>>>> Date: Wed Dec 21 20:19:53 2016 +0100 >>>>>> >>>>>> cpu/hotplug: Remove obsolete cpu hotplug register/unregister >>>>>> functions >>>>>> >>>>>> hotcpu_notifier(), cpu_notifier(), __hotcpu_notifier(), >>>>>> __cpu_notifier(), >>>>>> register_hotcpu_notifier(), register_cpu_notifier(), >>>>>> __register_hotcpu_notifier(), __register_cpu_notifier(), >>>>>> unregister_hotcpu_notifier(), unregister_cpu_notifier(), >>>>>> __unregister_hotcpu_notifier(), __unregister_cpu_notifier() >>>>>> >>>>>> >>>>>> Signed-off-by: Lei Yang >>>>>> --- >>>>>> tools/testing/selftests/cpu-hotplug/config | 1 - >>>>>> 1 file changed, 1 deletion(-) >>>>>> >>>>>> diff --git a/tools/testing/selftests/cpu-hotplug/config >>>>>> b/tools/testing/selftests/cpu-hotplug/config >>>>>> index e6ab090..d4aca2a 100644 >>>>>> --- a/tools/testing/selftests/cpu-hotplug/config >>>>>> +++ b/tools/testing/selftests/cpu-hotplug/config >>>>>> @@ -1,2 +1 @@ >>>>>> CONFIG_NOTIFIER_ERROR_INJECTION=y >>>>>> -CONFIG_CPU_NOTIFIER_ERROR_INJECT=m >>>>>> >>>>> Yes. It is removed from the kernel. However, selftests from the latest >>>>> release do get run routinely on older stable releases. Dropping the >>>>> config will impact coverage on older releases. >>>>> >>>>> Thomas/Greg, >>>>> >>>>> Any ideas on what we should do about this. On one hand it is a good idea >>>>> to remove it, however my concern is coverage on older releases. >>>> Can you check the kernel version on which you are running and do it >>>> runtime >>>> conditionally? >>>> >>> I have been avoiding adding kernel version checks to tests. Maybe this is >>> one exception since the functionality is obsoleted. >> >> >> I think the baseline is that we only assure kselftest works on the release >> it belongs to, for example, removing this config for the >> version above 4.10, keep it in old release. but looks it doesn't work like >> this way. >> >> I think We can't assure latest kselftest works still well on a very older >> releases >> yes, for some features it's common for each release. but we have some >> features that are only available in newer >> release. even for the common features, it's difficult to make sure it >> still works well for each >> release. maintenance is a big effort if we use something like version check. >> you never know what changes will make >> for general feature in the future release although it's common right now. > As Greg and several others have reiterated - the tests should be able > to check for presence of a feature, run it if it's applicable, and > skip if it's not. It really isn't about kernel version check, but > writing code and test in such a way that tests can 'degrade > gracefully', rather than fail. There are several good examples for the > same. > > The idea of running newer tests is to gain coverage on older kernels > for features still present in them, but tests weren't available at the > time of the kernel tagging. so we actually don't have version control for kselftest? anytime, we use the latest one I thought we recommended use the one in 4.12 if we want to test 4.12 kernel, not to use the one in newer version > Hope this helps clear the doubt? I'm wondering how do you determine this patch apply to which release. I don't understand "Dropping the config will impact coverage on older releases" , we can just don't apply it to the release older than 4.10. then the coverage doesn't drop. Lei >> Lei >> >> >>> In any case, just removing the config isn't the complete solution. I will >>> have to think about this some. >>> >>> thanks, >>> -- Shuah >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-kselftest" >>> in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > Best, > Sumit. > -- > To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html