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Date: Mon, 14 Jul 2014 10:40:19 +0400
From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
        Dave Hansen <dave.hansen@intel.com>, Hugh Dickins <hughd@google.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Jerome Marchand <jmarchan@redhat.com>, linux-kernel@vger.kernel.org,
        Naoya Horiguchi <nao.horiguchi@gmail.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Pavel Emelyanov <xemul@parallels.com>,
        Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [PATCH -mm v5 12/13] mm: /proc/pid/clear_refs: avoid
 split_huge_page()
Message-ID: <20140714064019.GF19702@moon>
References: <1405103749-23506-1-git-send-email-n-horiguchi@ah.jp.nec.com>
 <1405103749-23506-13-git-send-email-n-horiguchi@ah.jp.nec.com>
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On Fri, Jul 11, 2014 at 02:35:48PM -0400, Naoya Horiguchi wrote:
> From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> 
> Currently pagewalker splits all THP pages on any clear_refs request.  It's
> not necessary.  We can handle this on PMD level.
> 
> One side effect is that soft dirty will potentially see more dirty memory,
> since we will mark whole THP page dirty at once.
> 
> Sanity checked with CRIU test suite. More testing is required.
> 
> ChangeLog:
> - move code for thp to clear_refs_pte_range()
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Pavel Emelyanov <xemul@parallels.com>
> Cc: Andrea Arcangeli <aarcange@redhat.com>
> Cc: Dave Hansen <dave.hansen@intel.com>
> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> Cc: Cyrill Gorcunov <gorcunov@gmail.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>