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From: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Subject: Re: [PATCH v2 03/12] mm: thp: introduce separate TTU flag for thp
 freezing
To: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>, linux-mm@kvack.org
References: <1478561517-4317-1-git-send-email-n-horiguchi@ah.jp.nec.com>
 <1478561517-4317-4-git-send-email-n-horiguchi@ah.jp.nec.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Hugh Dickins <hughd@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Dave Hansen <dave.hansen@intel.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        Michal Hocko <mhocko@kernel.org>, Vlastimil Babka <vbabka@suse.cz>,
        Pavel Emelyanov <xemul@parallels.com>, Zi Yan <zi.yan@cs.rutgers.edu>,
        Balbir Singh <bsingharora@gmail.com>, linux-kernel@vger.kernel.org,
        Naoya Horiguchi <nao.horiguchi@gmail.com>
Date: Thu, 10 Nov 2016 14:01:56 +0530
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On 11/08/2016 05:01 AM, Naoya Horiguchi wrote:
> TTU_MIGRATION is used to convert pte into migration entry until thp split
> completes. This behavior conflicts with thp migration added later patches,

Hmm, could you please explain why it conflicts with the PMD based
migration without split ? Why TTU_MIGRATION cannot be used to
freeze/hold on the PMD while it's being migrated ?