From: Ingo Molnar <mingo@elte.hu>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: x86@kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Jan Beulich <jbeulich@novell.com>,
Xen-devel <xen-devel@lists.xensource.com>
Subject: Re: [PATCH] xen: avoid hypercalls when updating unpinned pud/pmd
Date: Mon, 2 Jun 2008 13:25:08 +0200 [thread overview]
Message-ID: <20080602112508.GD18586@elte.hu> (raw)
In-Reply-To: <48409ABB.20301@goop.org>
* Jeremy Fitzhardinge <jeremy@goop.org> wrote:
> When operating on an unpinned pagetable (ie, one under construction or
> destruction), it isn't necessary to use a hypercall to update a
> pud/pmd entry. Jan Beulich observed that a similar optimisation
> avoided many thousands of hypercalls while doing a kernel build.
>
> One tricky part is that early in the kernel boot there's no page
> structure, so we can't check to see if the page is pinned. In that
> case, we just always use the hypercall.
>
> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
> Cc: Jan Beulich <jbeulich@novell.com>
applied to tip/x86/xen, thanks Jeremy.
Ingo
WARNING: multiple messages have this Message-ID (diff)
From: Ingo Molnar <mingo@elte.hu>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Xen-devel <xen-devel@lists.xensource.com>,
x86@kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Jan Beulich <jbeulich@novell.com>
Subject: Re: [PATCH] xen: avoid hypercalls when updating unpinned pud/pmd
Date: Mon, 2 Jun 2008 13:25:08 +0200 [thread overview]
Message-ID: <20080602112508.GD18586@elte.hu> (raw)
In-Reply-To: <48409ABB.20301@goop.org>
* Jeremy Fitzhardinge <jeremy@goop.org> wrote:
> When operating on an unpinned pagetable (ie, one under construction or
> destruction), it isn't necessary to use a hypercall to update a
> pud/pmd entry. Jan Beulich observed that a similar optimisation
> avoided many thousands of hypercalls while doing a kernel build.
>
> One tricky part is that early in the kernel boot there's no page
> structure, so we can't check to see if the page is pinned. In that
> case, we just always use the hypercall.
>
> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
> Cc: Jan Beulich <jbeulich@novell.com>
applied to tip/x86/xen, thanks Jeremy.
Ingo
next prev parent reply other threads:[~2008-06-02 11:25 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-31 0:24 [PATCH] xen: avoid hypercalls when updating unpinned pud/pmd Jeremy Fitzhardinge
2008-05-31 0:24 ` Jeremy Fitzhardinge
2008-06-02 11:25 ` Ingo Molnar [this message]
2008-06-02 11:25 ` Ingo Molnar
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