Re: [PATCH] selftests: remove obsolete kconfig fragment for cpu-hotplug

[lyang0 <lei.yang@windriver.com>]

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 <Lei.Yang@windriver.com>
>>>>
>>>> Kconfig CONFIG_CPU_NOTIFIER_ERROR_INJECT has been removed since kernel 4.10
>>>> check commit:
>>>>      commit 530e9b76ae8f863dfdef4a6ad0b38613d32e8c3f
>>>>      Author: Thomas Gleixner <tglx@linutronix.de>
>>>>      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()
>>>>       <snip>
>>>>
>>>> Signed-off-by: Lei Yang <Lei.Yang@windriver.com>
>>>> ---
>>>>   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.

Lei


> In any case, just removing the config isn't the complete solution. I will
> have to think about this some.
>
> thanks,
> -- Shuah
>
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