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Re: [Xen-devel] TMEM + pv_ops kernel?

To: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
Subject: Re: [Xen-devel] TMEM + pv_ops kernel?
From: Rick Boone <rick@xxxxxxxxxxxxxx>
Date: Fri, 14 May 2010 18:13:38 -0700
Cc: Fitzhardinge <jeremy@xxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Jeremy, "konrad.wilk@xxxxxxxxxx" <konrad.wilk@xxxxxxxxxx>
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Hey Dan,

I'm currently working with the xen/stable-2.6.32.x branch ( in particular), from Jeremy's repo. I figured we would try to standardize around that, since the xen wiki says it's gonna be the branch thats maintained long term.

-- Rick

On 05/14/2010 03:59 PM, Dan Magenheimer wrote:

Hi Rick –

Which exact pv_ops tree do you expect to use?  The Linux patch is slightly different on each Linux version and I don’t know if/how patches such as tmem will get transferred across Jeremy’s and Konrad’s different pv_ops trees.



From: Rick Boone [mailto:rick@xxxxxxxxxxxxxx]
Sent: Friday, May 14, 2010 4:38 PM
To: xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-devel] TMEM + pv_ops kernel?


Hey Dan,

Yeah, I'm planning on using pv_ops for both the dom0 and domU kernels.

Any movement towards making TMEM available would be great; it's one of the key things we're looking forward to testing and using (along with Remus)

I'm systems engineer at a company running about 50 blogs/social networking websites (http://buzz-media.com) , all on top of a heavily virtualized infrastructure (Xen [v3.2] is our sole virt platform) . We've got about 80 dom0's, holding about 125 domU's and on a few of those boxes, especially those holding one or more of our web server domU's, we run into "out of memory" crashes from time to time. So, we're hoping to see if TMEM helps reduce our memory woes. We tend to mix and match types of domU's within dom0's, so some boxes will have 1 memory-hungry web server, alongside a number of smaller, low-usage, low-memory, developer boxes. From what we've read, TMEM might be perfect for our setup.

-- Rick

On 05/14/2010 08:26 AM, Dan Magenheimer wrote:

Hi Rick –


Tmem is primarily of use in PV guests, less so in dom0.  Are you putting pv_ops kernels in your PV guests (domUs)?


If so, Jeremy has been a big proponent of tmem and we can work together to get it into his pv_ops tree.   But I think most of the focus for the pv_ops work has been to provide dom0 support.  Upstream kernels already provide domU support, so I’ve been instead working on the linux-kernel-mailing-list toward getting tmem patches accepted upstream.


If not, just using a tmem-modified dom0 will probably not help you.   I have been working on tmem-modified rpm’s for various RedHat-ish kernels and I know Jan Beulich has been working on putting tmem support into various SuSE kernels.


I’d also be interested in more information about your planned usage model for tmem.





From: Rick Boone [mailto:rick@xxxxxxxxxxxxxx]
Sent: Thursday, May 13, 2010 4:17 PM
To: xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-devel] TMEM + pv_ops kernel?



I'm building Jeremy's pv_ops dom0 kernel ( for use with Xen 4.0 and it looks like the Transcendant Memory options arent in the kernel config. Is TMEM not available in pv_ops? I've been looking forward to using it with Xen4, but also really wanna work with pv_ops moving forward.

Thanks alot, 
-- Rick

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