From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Keir Fraser <keir@xensource.com>
Cc: Hugh Dickins <hugh@veritas.com>,
Andrew Morton <akpm@linux-foundation.org>,
David Rientjes <rientjes@google.com>,
Zachary Amsden <zach@vmware.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Rusty Russell <rusty@rustcorp.com.au>,
Jan Beulich <jbeulich@novell.com>, Andi Kleen <ak@suse.de>,
Ken Chen <kenchen@google.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, 05 Oct 2007 13:35:31 -0700 [thread overview]
Message-ID: <4706A013.6080003@goop.org> (raw)
In-Reply-To: <C32C1AD6.167B3%keir@xensource.com>
Keir Fraser wrote:
> The PREEMPT_BITS limitation is a good argument for at least taking the pte
> locks in small batches though (small batches is preferable to one-by-one
> since we will want to batch the make-readonly-and-pin hypercall requests to
> amortise the cost of the hypervisor trap).
Hm, I don't see how we can avoid holding locks for the whole pagetable
at once. We need to hold the locks from between marking a particular
pte page RO until the whole pagetable is pinned; if we don't, pte
updates can come in from other cpus, which will fault on the RO but
won't be fixed up by Xen.
Could we avoid it by doing a series of partial pins, locking and
unlocking each one in the process, and then pin the whole pagetable?
J
next prev parent reply other threads:[~2007-10-05 20:35 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <C32B9BEC.E711%keir@xensource.com>
2007-10-05 8:03 ` race with page_referenced_one->ptep_test_and_clear_young and pagetable setup/pulldown 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 [this message]
2007-10-05 1:43 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
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
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