From: Cyrill Gorcunov <gorcunov@gmail.com>
To: David Vrabel <david.vrabel@citrix.com>
Cc: Andy Lutomirski <luto@amacapital.net>,
Pavel Emelyanov <xemul@parallels.com>,
Andrew Morton <akpm@linux-foundation.org>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Xen-devel@lists.xen.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Jan Beulich <jbeulich@suse.com>
Subject: Re: Regression: x86/mm: new _PTE_SWP_SOFT_DIRTY bit conflicts with existing use
Date: Wed, 21 Aug 2013 18:12:23 +0400 [thread overview]
Message-ID: <20130821141223.GS18673@moon> (raw)
In-Reply-To: <5214C524.1050900@citrix.com>
On Wed, Aug 21, 2013 at 02:48:20PM +0100, David Vrabel wrote:
> All,
>
> 179ef71c (mm: save soft-dirty bits on swapped pages) introduces a new
> PTE bit on x86 _PTE_SWP_SOFT_DIRTY which has the same value as _PTE_PSE
> and _PTE_PAT.
>
> With a Xen PV guest, the use of the _PTE_PAT will result in the page
> having unexpected cachability which will introduce a range of subtle
> performance and correctness issues. Xen programs the entry 4 in the PAT
> table with WC so a page that was previously WB will end up as WC.
>
David, could you please explain, Xen keeps and analyze _PTE_PAT bit
for ptes which are not present?
next prev parent reply other threads:[~2013-08-21 14:12 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-21 13:48 Regression: x86/mm: new _PTE_SWP_SOFT_DIRTY bit conflicts with existing use David Vrabel
2013-08-21 13:53 ` konrad wilk
2013-08-21 14:11 ` H. Peter Anvin
2013-08-21 14:19 ` Cyrill Gorcunov
2013-08-21 14:22 ` H. Peter Anvin
2013-08-21 14:29 ` Cyrill Gorcunov
2013-08-21 16:30 ` Linus Torvalds
2013-08-21 16:42 ` Cyrill Gorcunov
2013-08-21 23:05 ` Cyrill Gorcunov
2013-08-21 23:42 ` Andi Kleen
2013-08-22 5:49 ` Cyrill Gorcunov
2013-08-22 6:37 ` Minchan Kim
2013-08-22 13:12 ` Cyrill Gorcunov
2013-08-27 22:04 ` Benjamin Herrenschmidt
2013-08-21 14:12 ` Cyrill Gorcunov [this message]
2013-08-21 14:22 ` H. Peter Anvin
2013-08-21 14:53 ` Jan Beulich
2013-08-21 14:58 ` H. Peter Anvin
2013-08-21 15:42 ` Cyrill Gorcunov
2013-08-21 16:03 ` Jan Beulich
2013-08-21 16:19 ` Cyrill Gorcunov
2013-08-21 16:56 ` David Vrabel
2013-08-21 17:25 ` Cyrill Gorcunov
2013-08-21 18:17 ` Cyrill Gorcunov
2013-08-21 18:50 ` H. Peter Anvin
2013-08-21 19:03 ` Cyrill Gorcunov
2013-08-21 19:07 ` Andy Lutomirski
2013-08-21 19:20 ` Cyrill Gorcunov
2013-08-21 19:21 ` Pavel Emelyanov
2013-08-21 23:04 ` Linus Torvalds
2013-08-22 0:51 ` Dave Jones
2013-08-22 5:44 ` Cyrill Gorcunov
2013-08-22 6:41 ` Pavel Emelyanov
2013-08-22 7:47 ` Jan Beulich
2013-08-22 9:32 ` David Vrabel
2013-08-22 10:16 ` Pavel Emelyanov
2013-08-22 6:56 ` Jan Beulich
2013-08-22 7:03 ` Cyrill Gorcunov
2013-08-22 7:27 ` Jan Beulich
2013-08-22 11:27 ` Cyrill Gorcunov
2013-08-22 11:33 ` Jan Beulich
2013-08-22 12:18 ` Pavel Emelyanov
2013-08-21 17:28 ` Andy Lutomirski
2013-08-22 7:54 ` Jan Beulich
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20130821141223.GS18673@moon \
--to=gorcunov@gmail.com \
--cc=Xen-devel@lists.xen.org \
--cc=akpm@linux-foundation.org \
--cc=boris.ostrovsky@oracle.com \
--cc=david.vrabel@citrix.com \
--cc=hpa@zytor.com \
--cc=jbeulich@suse.com \
--cc=konrad.wilk@oracle.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@amacapital.net \
--cc=mingo@redhat.com \
--cc=torvalds@linux-foundation.org \
--cc=xemul@parallels.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox