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Subject: Re: LTP hugemmap05 test case failure on arm64 with linux-next
 (next-20190613)
From:   Qian Cai <cai@lca.pw>
In-Reply-To: <054b6532-a867-ec7c-0a72-6a58d4b2723e@arm.com>
Date:   Sun, 16 Jun 2019 21:41:09 -0400
Cc:     Will Deacon <will.deacon@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        linux-arm-kernel@lists.infradead.org
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Message-Id: <EC704BC3-62FF-4DCE-8127-40279ED50D65@lca.pw>
References: <1560461641.5154.19.camel@lca.pw>
 <20190614102017.GC10659@fuggles.cambridge.arm.com>
 <1560514539.5154.20.camel@lca.pw>
 <054b6532-a867-ec7c-0a72-6a58d4b2723e@arm.com>
To:     Anshuman Khandual <anshuman.khandual@arm.com>
Sender: linux-kernel-owner@vger.kernel.org
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> On Jun 16, 2019, at 9:32 PM, Anshuman Khandual =
<anshuman.khandual@arm.com> wrote:
>=20
> Hello Qian,
>=20
> On 06/14/2019 05:45 PM, Qian Cai wrote:
>> On Fri, 2019-06-14 at 11:20 +0100, Will Deacon wrote:
>>> Hi Qian,
>>>=20
>>> On Thu, Jun 13, 2019 at 05:34:01PM -0400, Qian Cai wrote:
>>>> LTP hugemmap05 test case [1] could not exit itself properly and =
then degrade
>>>> the
>>>> system performance on arm64 with linux-next (next-20190613). The =
bisection
>>>> so
>>>> far indicates,
>>>>=20
>>>> BAD:  30bafbc357f1 Merge remote-tracking branch =
'arm64/for-next/core'
>>>> GOOD: 0c3d124a3043 Merge remote-tracking branch =
'arm64-fixes/for-next/fixes'
>>>=20
>>> Did you finish the bisection in the end? Also, what config are you =
using
>>> (you usually have something fairly esoteric ;)?
>>=20
>> No, it is still running.
>>=20
>> https://raw.githubusercontent.com/cailca/linux-mm/master/arm64.config
>>=20
>=20
> Were you able to bisect the problem till a particular commit ?

Not yet, it turned out the test case needs to run a few times (usually =
within 5) to reproduce, so the previous bisection was totally wrong =
where it assume the bad commit will fail every time. Once reproduced, =
the test case becomes unkillable stuck in the D state.

I am still in the middle of running a new round of bisection. The =
current progress is,

35c99ffa20ed GOOD (survived 20 times)
def0fdae813d BAD=