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Date: Wed, 10 Sep 2014 22:41:04 -0700
From: Peter Feiner <pfeiner@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Cyrill Gorcunov <gorcunov@openvz.org>,
        Pavel Emelyanov <xemul@parallels.com>, Jamie Liu <jamieliu@google.com>,
        Hugh Dickins <hughd@google.com>,
        Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Subject: Re: [PATCH] mm: softdirty: unmapped addresses between VMAs are clean
Message-ID: <20140911054104.GA31069@google.com>
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 <20140910163628.66302ac77f7835ba5df2f49c@linux-foundation.org>
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On Wed, Sep 10, 2014 at 04:36:28PM -0700, Andrew Morton wrote:
> On Wed, 10 Sep 2014 16:24:46 -0700 Peter Feiner <pfeiner@google.com> wrote:
> > @@ -1048,32 +1048,51 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
> > +	while (1) {
> > +		unsigned long vm_start = end;
> 
> Did you really mean to do that?  If so, perhaps a little comment to
> explain how it works?

It's the same idea that I used in the pagemap_pte_hole patch that I submitted
today: if vma is NULL, then we fill in the pagemap from (addr) to (end) with
non-present pagemap entries. 

Should I submit a v2 with a comment?