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Date:   Wed, 8 Apr 2020 17:21:45 +0300
From:   "Kirill A. Shutemov" <kirill@shutemov.name>
To:     Zi Yan <ziy@nvidia.com>
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
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On Mon, Apr 06, 2020 at 02:50:32PM -0400, Zi Yan wrote:
>       khugepaged-58    [001] ....  9913.990380: mm_khugepaged_scan_pmd: mm=00000000283d31fc, scan_pfn=0x2ae4bd, writable=0, referenced=512, none_or_zero=0, status=no_writable_page, unmapped=0

Looks like all failures due to lack of writable ptes. That's very strange
because we write to the page on fill.

You've mentioned that you run it in VM. I wounder if it can be a
virtualizaiton artefact. I run tests under KVM and they are fine. What is
your virtualization setup?

-- 
 Kirill A. Shutemov