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 file pages
Date: Sat, 27 Jul 2013 10:25:12 +0400 [thread overview]
Message-ID: <20130727062512.GC8508@moon> (raw)
In-Reply-To: <CALCETrW7Ukh8KfKzpNgRc1D_5OK1o7bmEmFbtQTYoSoFiOSeKw@mail.gmail.com>
On Fri, Jul 26, 2013 at 02:36:51PM -0700, Andy Lutomirski wrote:
> >> Unless I'm misunderstanding this, it's saving the bit in the
> >> non-present PTE. This sounds wrong -- what happens if the entire pmd
> >
> > It's the same as encoding pgoff in pte entry (pte is not present),
> > but together with pgoff we save soft-bit status, later on #pf we decode
> > pgoff and restore softbit back if it was there, pte itself can't disappear
> > since it holds pgoff information.
>
> Isn't that only the case for nonlinear mappings?
Andy, I'm somehow lost, pte either exist with file encoded, either not,
when pud/ptes are zapped and any access to it should cause #pf pointing
kernel to read/write data from file to a page, if it happens on write
the pte is obtaining dirty bit (which always set together with soft
bit).
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next prev parent reply other threads:[~2013-07-27 6:25 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-26 20:18 [PATCH] mm: Save soft-dirty bits on file pages Cyrill Gorcunov
2013-07-26 20:55 ` Andy Lutomirski
2013-07-26 21:18 ` Cyrill Gorcunov
2013-07-26 21:36 ` Andy Lutomirski
2013-07-27 6:25 ` Cyrill Gorcunov [this message]
2013-07-27 17:06 ` Andy Lutomirski
2013-07-27 21:01 ` Cyrill Gorcunov
2013-07-27 19:29 ` Pavel Emelyanov
2013-07-28 9:28 ` Pavel Emelyanov
2013-07-29 14:08 ` Pavel Emelyanov
2013-07-29 14:14 ` Cyrill Gorcunov
2013-07-29 14:24 ` Pavel Emelyanov
2013-07-29 14:36 ` Cyrill Gorcunov
2013-07-29 14:58 ` Aneesh Kumar K.V
2013-07-29 15:02 ` Cyrill Gorcunov
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