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Date:   Mon, 24 Jun 2019 10:35:07 +0100
From:   Will Deacon <will@kernel.org>
To:     Qian Cai <cai@lca.pw>
Cc:     Anshuman Khandual <anshuman.khandual@arm.com>,
        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
Subject: Re: LTP hugemmap05 test case failure on arm64 with linux-next
 (next-20190613)
Message-ID: <20190624093507.6m2quduiacuot3ne@willie-the-truck>
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Hi Qian Cai,

On Sun, Jun 16, 2019 at 09:41:09PM -0400, Qian Cai wrote:
> > On Jun 16, 2019, at 9:32 PM, Anshuman Khandual <anshuman.khandual@arm.com> wrote:
> > On 06/14/2019 05:45 PM, Qian Cai wrote:
> >> On Fri, 2019-06-14 at 11:20 +0100, Will Deacon wrote:
> >>> 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,
> >>>> 
> >>>> BAD:  30bafbc357f1 Merge remote-tracking branch 'arm64/for-next/core'
> >>>> GOOD: 0c3d124a3043 Merge remote-tracking branch 'arm64-fixes/for-next/fixes'
> >>> 
> >>> Did you finish the bisection in the end? Also, what config are you using
> >>> (you usually have something fairly esoteric ;)?
> >> 
> >> No, it is still running.
> >> 
> >> https://raw.githubusercontent.com/cailca/linux-mm/master/arm64.config
> >> 
> > 
> > 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

Just wondering if you got anywhere with this? We've failed to reproduce the
problem locally.

Will