From: David Vrabel <david.vrabel@citrix.com>
To: Matt Rushton <mvrushton@gmail.com>, <konrad.wilk@oracle.com>,
<boris.ostrovsky@oracle.com>
Cc: <msw@amazon.com>, <linux-kernel@vger.kernel.org>,
<xen-devel@lists.xensource.com>,
Matt Rushton <mrushton@amazon.com>
Subject: Re: [PATCH v3 2/2] xen/setup: Remap Xen Identity Mapped RAM
Date: Mon, 11 Aug 2014 18:40:08 +0100 [thread overview]
Message-ID: <53E8FFF8.8070800@citrix.com> (raw)
In-Reply-To: <1407778441-26604-2-git-send-email-mrushton@amazon.com>
On 11/08/14 18:34, Matt Rushton wrote:
> Instead of ballooning up and down dom0 memory this remaps the existing mfns
> that were replaced by the identity map. The reason for this is that the
> existing implementation ballooned memory up and and down which caused dom0
> to have discontiguous pages. In some cases this resulted in the use of bounce
> buffers which reduced network I/O performance significantly. This change will
> honor the existing order of the pages with the exception of some boundary
> conditions.
>
> To do this we need to update both the Linux p2m table and the Xen m2p table.
> Particular care must be taken when updating the p2m table since it's important
> to limit table memory consumption and reuse the existing leaf pages which get
> freed when an entire leaf page is set to the identity map. To implement this,
> mapping updates are grouped into blocks with table entries getting cached
> temporarily and then released.
What's changed in this version?
David
WARNING: multiple messages have this Message-ID (diff)
From: David Vrabel <david.vrabel@citrix.com>
To: Matt Rushton <mvrushton@gmail.com>,
konrad.wilk@oracle.com, boris.ostrovsky@oracle.com
Cc: msw@amazon.com, linux-kernel@vger.kernel.org,
xen-devel@lists.xensource.com, Matt Rushton <mrushton@amazon.com>
Subject: Re: [PATCH v3 2/2] xen/setup: Remap Xen Identity Mapped RAM
Date: Mon, 11 Aug 2014 18:40:08 +0100 [thread overview]
Message-ID: <53E8FFF8.8070800@citrix.com> (raw)
In-Reply-To: <1407778441-26604-2-git-send-email-mrushton@amazon.com>
On 11/08/14 18:34, Matt Rushton wrote:
> Instead of ballooning up and down dom0 memory this remaps the existing mfns
> that were replaced by the identity map. The reason for this is that the
> existing implementation ballooned memory up and and down which caused dom0
> to have discontiguous pages. In some cases this resulted in the use of bounce
> buffers which reduced network I/O performance significantly. This change will
> honor the existing order of the pages with the exception of some boundary
> conditions.
>
> To do this we need to update both the Linux p2m table and the Xen m2p table.
> Particular care must be taken when updating the p2m table since it's important
> to limit table memory consumption and reuse the existing leaf pages which get
> freed when an entire leaf page is set to the identity map. To implement this,
> mapping updates are grouped into blocks with table entries getting cached
> temporarily and then released.
What's changed in this version?
David
next prev parent reply other threads:[~2014-08-11 17:40 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-11 17:34 [PATCH v3 1/2] xen/setup: Remove Identity Map Debug Message Matt Rushton
2014-08-11 17:34 ` [PATCH v3 2/2] xen/setup: Remap Xen Identity Mapped RAM Matt Rushton
2014-08-11 17:40 ` David Vrabel [this message]
2014-08-11 17:40 ` David Vrabel
2014-08-11 17:41 ` Matt Wilson
2014-08-11 19:00 ` Matthew Rushton
2014-08-27 10:28 ` David Vrabel
2014-08-27 10:28 ` David Vrabel
-- strict thread matches above, loose matches on Subject: below --
2014-08-11 18:57 [PATCH v3 1/2] xen/setup: Remove Identity Map Debug Message Matt Rushton
2014-08-11 18:57 ` [PATCH v3 2/2] xen/setup: Remap Xen Identity Mapped RAM Matt Rushton
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