From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Pavel Emelyanov <xemul@parallels.com>,
James Bottomley <James.Bottomley@hansenpartnership.com>,
Linux MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
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
Date: Thu, 25 Jul 2013 11:07:19 +0400 [thread overview]
Message-ID: <20130725070719.GB27992@moon> (raw)
In-Reply-To: <CALCETrVRQBLrQBL8_Zu0VqBRkDXXr2np57-gt4T59A4jG9jMZw@mail.gmail.com>
On Wed, Jul 24, 2013 at 12:40:22PM -0700, Andy Lutomirski wrote:
>
> Hmm. So there are at least three kinds of memory:
>
> Anonymous pages: soft-dirty works
> Shared file-backed pages: soft-dirty does not work
> Private file-backed pages: soft-dirty works (but see below)
>
> Perhaps another bit should be allocated to expose to userspace either
> "soft-dirty", "soft-clean", or "soft-dirty unsupported"?
> There's another possible issue with private file-backed pages, though:
> how do you distinguish clean-and-not-cowed from cowed-but-soft-clean?
> (The former will reflect changes in the underlying file, I think, but
> the latter won't.)
When fault happens with cow allocation (on write) the pte get soft dirty
bit set (the code uses pte_mkdirty(entry) in __do_fault) and until we
explicitly clean the bit it remains set. Or you mean something else?
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next prev parent reply other threads:[~2013-07-25 7:07 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-24 16:08 [PATCH] mm: Save soft-dirty bits on swapped pages Cyrill Gorcunov
2013-07-24 16:23 ` Andy Lutomirski
2013-07-24 16:37 ` Cyrill Gorcunov
2013-07-24 17:06 ` Andy Lutomirski
2013-07-24 17:17 ` Cyrill Gorcunov
2013-07-24 17:36 ` James Bottomley
2013-07-24 17:42 ` Andy Lutomirski
2013-07-24 18:15 ` Cyrill Gorcunov
2013-07-24 18:21 ` Andy Lutomirski
2013-07-24 18:52 ` Cyrill Gorcunov
2013-07-24 18:55 ` Pavel Emelyanov
2013-07-24 19:04 ` Cyrill Gorcunov
2013-07-24 19:18 ` Cyrill Gorcunov
2013-07-24 19:40 ` Andy Lutomirski
2013-07-25 7:07 ` Cyrill Gorcunov [this message]
2013-07-25 7:29 ` Pavel Emelyanov
2013-07-25 8:26 ` Hush Bensen
2013-07-25 8:43 ` Pavel Emelyanov
2013-07-25 16:02 ` Andy Lutomirski
2013-07-24 18:52 ` Pavel Emelyanov
2013-07-24 18:52 ` Pavel Emelyanov
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