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Subject: Re: [PATCH 2/8] selftests/vm: use a common gup_test.h
To:     Jason Gunthorpe <jgg@ziepe.ca>, John Hubbard <jhubbard@nvidia.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Jonathan Corbet <corbet@lwn.net>,
        =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= <jglisse@redhat.com>,
        Ralph Campbell <rcampbell@nvidia.com>,
        Shuah Khan <shuah@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, linux-mm@kvack.org,
        linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-s390@vger.kernel.org, Shuah Khan <skhan@linuxfoundation.org>
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 <20200928125739.GP9916@ziepe.ca>
 <6481e78f-c70d-133a-ff4a-325b5cd8fd5d@nvidia.com>
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 <aab477bf-4353-5e6b-4cc9-9872c9376ed2@nvidia.com>
 <20200929175524.GX9916@ziepe.ca>
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 <20200929190816.GY9916@ziepe.ca>
 <3022912c-f11b-f564-3a8a-f516ca259a37@nvidia.com>
 <20200929195356.GZ9916@ziepe.ca>
From:   Shuah Khan <skhan@linuxfoundation.org>
Message-ID: <64bb5ba7-77f7-2f09-44f0-29ee9329b183@linuxfoundation.org>
Date:   Tue, 29 Sep 2020 14:00:44 -0600
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On 9/29/20 1:53 PM, Jason Gunthorpe wrote:
> On Tue, Sep 29, 2020 at 12:48:43PM -0700, John Hubbard wrote:
>> On 9/29/20 12:08 PM, Jason Gunthorpe wrote:
>>> On Tue, Sep 29, 2020 at 11:59:55AM -0700, John Hubbard wrote:
>>>> On 9/29/20 10:55 AM, Jason Gunthorpe wrote:
>>>>> On Tue, Sep 29, 2020 at 10:44:31AM -0700, John Hubbard wrote:
>>>>>> On 9/29/20 9:35 AM, Jason Gunthorpe wrote:
>>>>>>> On Mon, Sep 28, 2020 at 01:10:24PM -0700, John Hubbard wrote:
>>>>>>>> On 9/28/20 5:57 AM, Jason Gunthorpe wrote:
>>>>>>>>> On Sun, Sep 27, 2020 at 11:21:53PM -0700, John Hubbard wrote:
>>>> ...
>>>>>> I don't see any "gcc -m" type of dependency generation pass happening
>>>>>> in this relatively simple Make system.
>>>>>
>>>>> It happens with -MD, all the deps are stored in files like mm/.init-mm.o.cmd
>>>>> and sucked into the build.
>>>>
>>>> You are thinking of kbuild. This is not kbuild. There are no such artifacts
>>>> being generated.
>>>
>>> Oh. Really? That's horrible.
>>>
>>
>> Well, yes, it's not a perfect build system down here in selftests/. Are you saying
>> that it is worth upgrading? I'm open to suggestions and ideas for improvements,
>> and at the moment, I have the miniature build system here mostly loaded into my
>> head. So for a brief shining moment I can probably understand it well enough to
>> work on it. :)
> 
> I only remarked because I didn't know it wasn't using kbuild. I
> thought it would have used the existing HOSTCC stuff, not sure why it
> is special.
> 
> The only investment that seems worthwhile would be to switch it to use
> the normal kbuild stuff??
> 

I explored switching to kbuild at the kernel summit last year during
my kselftest where are we talk.

There was push back from several developers. We can definitely explore
it as long as we can still support being able to build and run
individual subsystem tests and doesn't break workflow for developers.

If you are up for it, propose a patch and we can discuss it.

thanks,
-- Shuah