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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Rik van Riel <riel@redhat.com>
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: Thu, 04 Oct 2007 21:15:18 -0700	[thread overview]
Message-ID: <4705BA56.5080605@goop.org> (raw)
In-Reply-To: <20071004215231.42b1bc21@bree.surriel.com>

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.  You'd need a Xen-specific
exception handler to do that, which would turn the whole thing into
Xen-specific code, and you're back at adding a pv-op.

    J


  reply	other threads:[~2007-10-05  4:15 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 [this message]
2007-10-05 13:17     ` Rik van Riel
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

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