Date: Wed, 24 Jul 2013 21:17:28 +0400
From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Linux MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>,
        Pavel Emelyanov <xemul@parallels.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Matt Mackall <mpm@selenic.com>,
        Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>,
        Marcelo Tosatti <mtosatti@redhat.com>,
        KOSAKI Motohiro <kosaki.motohiro@gmail.com>,
        Stephen Rothwell <sfr@canb.auug.org.au>
Subject: Re: [PATCH] mm: Save soft-dirty bits on swapped pages
Message-ID: <20130724171728.GH8508@moon>
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On Wed, Jul 24, 2013 at 10:06:53AM -0700, Andy Lutomirski wrote:
> > Hi Andy, if I understand you correctly "file-backed pages" are carried
> > in pte with _PAGE_FILE bit set and the swap soft-dirty bit won't be
> > used on them but _PAGE_SOFT_DIRTY will be set on write if only I've
> > not missed something obvious (Pavel?).
> 
> If I understand this stuff correctly, the vmscan code calls
> try_to_unmap when it reclaims memory, which makes its way into
> try_to_unmap_one, which clears the pte (and loses the soft-dirty bit).

Indeed, I was so stareing into swap that forgot about files. I'll do
a separate patch for that, thanks!
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