From: Rik van Riel <riel@redhat.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Hugh Dickens <hugh@veritas.com>,
David Rientjes <rientjes@google.com>,
Zachary Amsden <zach@vmware.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Rusty Russell <rusty@rustcorp.com.au>, Andi Kleen <ak@suse.de>,
Keir Fraser <keir@xensource.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: race with page_referenced_one->ptep_test_and_clear_young and pagetable setup/pulldown
Date: Fri, 5 Oct 2007 09:17:16 -0400 [thread overview]
Message-ID: <20071005091716.78d30446@bree.surriel.com> (raw)
In-Reply-To: <4705BA56.5080605@goop.org>
On Thu, 04 Oct 2007 21:15:18 -0700
Jeremy Fitzhardinge <jeremy@goop.org> wrote:
> Rik van Riel wrote:
> > Either of these two would work. Another alternative could be to
> > let test_and_clear_pte_flags have an exception table entry, where
> > we jump right to the next instruction if the instruction clearing
> > the flag fails.
> >
> > That is the essentially variant you need for Xen, except the fast
> > path is still exactly the same it is as when running on native
> > hardware.
> >
>
> Hm, that wouldn't end up clearing the bit.
Big deal. We don't care *that* much.
As long as the bit gets cleared 99.9% of the time, we're fine.
All that bit is for is determining when to swap out a page.
--
"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it." - Brian W. Kernighan
next prev parent reply other threads:[~2007-10-05 13:17 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-05 1:43 race with page_referenced_one->ptep_test_and_clear_young and pagetable setup/pulldown Jeremy Fitzhardinge
2007-10-05 1:52 ` Rik van Riel
2007-10-05 4:15 ` Jeremy Fitzhardinge
2007-10-05 13:17 ` Rik van Riel [this message]
2007-10-05 2:44 ` Andrew Morton
2007-10-05 4:08 ` Jeremy Fitzhardinge
2007-10-07 9:52 ` Nick Piggin
2007-10-05 11:36 ` Hugh Dickins
2007-10-05 18:58 ` Rik van Riel
2007-10-05 19:40 ` Jeremy Fitzhardinge
2007-10-05 19:56 ` Rik van Riel
2007-10-05 19:39 ` Jeremy Fitzhardinge
[not found] <C32B9BEC.E711%keir@xensource.com>
2007-10-05 8:03 ` Andi Kleen
2007-10-05 9:05 ` Jeremy Fitzhardinge
2007-10-05 9:15 ` Keir Fraser
2007-10-05 15:33 ` Hugh Dickins
2007-10-05 15:46 ` Keir Fraser
2007-10-05 16:48 ` Jeremy Fitzhardinge
2007-10-05 20:35 ` Jeremy Fitzhardinge
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=20071005091716.78d30446@bree.surriel.com \
--to=riel@redhat.com \
--cc=ak@suse.de \
--cc=akpm@linux-foundation.org \
--cc=hugh@veritas.com \
--cc=jeremy@goop.org \
--cc=keir@xensource.com \
--cc=linux-kernel@vger.kernel.org \
--cc=rientjes@google.com \
--cc=rusty@rustcorp.com.au \
--cc=torvalds@linux-foundation.org \
--cc=zach@vmware.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