Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Zi Yan <ziy@nvidia.com>
To:     "Kirill A. Shutemov" <kirill@shutemov.name>
CC:     <akpm@linux-foundation.org>,
        Andrea Arcangeli <aarcange@redhat.com>,
        "Yang Shi" <yang.shi@linux.alibaba.com>, <linux-mm@kvack.org>,
        <linux-kernel@vger.kernel.org>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCHv2 1/8] khugepaged: Add self test
Date:   Fri, 10 Apr 2020 11:03:09 -0400
Message-ID: <511724CE-3FF3-4535-BDB1-D4B9ACE9F3DA@nvidia.com>
In-Reply-To: <20200410145804.fczyvec4pngpep6t@box>
References: <20200403112928.19742-1-kirill.shutemov@linux.intel.com>
 <20200403112928.19742-2-kirill.shutemov@linux.intel.com>
 <D55D6A3A-47A1-41F5-B939-36EEA740CF72@nvidia.com>
 <20200410114739.b2ndracbyhsdmanv@box>
 <DF6A7119-D6D6-4679-A4B6-9A7570984D97@nvidia.com>
 <20200410145804.fczyvec4pngpep6t@box>
MIME-Version: 1.0
Content-Type: multipart/signed;
        boundary="=_MailMate_F5C90A71-D4C8-4685-BD1F-D7672BFC44C2_=";
        micalg=pgp-sha512; protocol="application/pgp-signature"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

--=_MailMate_F5C90A71-D4C8-4685-BD1F-D7672BFC44C2_=
Content-Type: text/plain; charset="UTF-8"; markup=markdown
Content-Transfer-Encoding: quoted-printable

On 10 Apr 2020, at 10:58, Kirill A. Shutemov wrote:

> External email: Use caution opening links or attachments
>
>
> On Fri, Apr 10, 2020 at 10:36:58AM -0400, Zi Yan wrote:
>> On 10 Apr 2020, at 7:47, Kirill A. Shutemov wrote:
>>
>>> External email: Use caution opening links or attachments
>>>
>>>
>>> On Mon, Apr 06, 2020 at 10:59:52AM -0400, Zi Yan wrote:
>>>> I ran this test with all patches from this series applied to Linus=E2=
=80=99s tree, but still see several failures. Is it expected?
>>>> The config file is attached. Let me know if I miss anything. BTW, I =
am running in a VM.
>>>>
>>>> Thanks.
>>>>
>>>> The output:
>>>>
>>>> =E2=9E=9C  ~ sudo ./khugepaged
>>>> Save THP and khugepaged settings... OK
>>>> Adjust settings... OK
>>>> Allocate huge page on fault... OK
>>>> Split huge PMD on MADV_DONTNEED... OK
>>>> Collapse fully populated PTE table.... Fail
>>>
>>> I was able to reproduce the issue. And it's fun failure mode.
>>>
>>> How did you get the test case inside the VM? Copy-paste source using =
'cat'
>>> or something similar inside the VM?
>>
>> First of all, the failure above was from a bare metal and was the only=

>> failure I saw, whereas I saw more failures in my VM. The test program
>> was not messed up in either environment.
>
> Hm. In the quote you are saying "BTW, I am running in a VM".

Sorry, misread the email thread. I was referring to another my email on r=
unning
tests on a bare metal, where only =E2=80=9CCollapse with max_ptes_swap pa=
ges swapped out=E2=80=9D
failed.

Here is the link to the email:
https://lore.kernel.org/linux-mm/C66E1309-2069-495B-BACD-7F3282C6EC7D@nvi=
dia.com/

>
>>
>> For VM failures I mentioned before, I used scp to copy the source code=

>> into the VM. My VM has its port 22 forwarded to host=E2=80=99s port 11=
022. =E2=80=9C-net
>> user,hostfwd=3Dtcp::11022-:22=E2=80=9D. I also copied a binary into my=
 VM and saw
>> the same failures.
>>
>> I kinda think the failures are not related to your patches but somethi=
ng else.
>>
>>>
>>> It screwed up CHECK_HUGE_FMT and CHECK_SWAP_FMT for me. Double back s=
lash
>>> was converted to single. As result check_huge() and check_swap() gave=
 the
>>> false-negative result all the time.
>>
>> It was not my case, since CHECK_HUGE_FMT and CHECK_SWAP_FMT from my
>> khugepaged.c match your patch code.
>>
>>>
>>> Could you check that the source of the test-case is not mangled and
>>> re-test if it is.
>>
>> I can confirm that the test-case is not mangled. I think it must be my=

>> VM setup or kernel configuration.
>>
>> Do you mind sharing your .config file with me and which kernel commit
>> you apply the patches on top of in your setup? I can look into it and
>> check what the problem is.
>
> My config is attached.

Thanks.

=E2=80=94
Best Regards,
Yan Zi

--=_MailMate_F5C90A71-D4C8-4685-BD1F-D7672BFC44C2_=
Content-Description: OpenPGP digital signature
Content-Disposition: attachment; filename="signature.asc"
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----
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=ix0J
-----END PGP SIGNATURE-----

--=_MailMate_F5C90A71-D4C8-4685-BD1F-D7672BFC44C2_=--