Re: [PATCH] Re: tmem on 4.1 (was Re: Freeze schedule)

["Olivier B." <xen.list@daevel.fr>]

Le 20/01/2011 08:17, Keir Fraser a écrit :
> On 19/01/2011 21:38, "Dan Magenheimer"<dan.magenheimer@oracle.com>  wrote:
>
>> Just to check again, has anyone actually seen a problem with
>> tmem enabled by default recently?  I agree that there is still
>> theoretically a problem, but there is the same problem with
>> normal guests doing lots of ballooning as well.  Also, note
>> that even if tmem defaults to enabled, the problem is impossible
>> unless a guest enables tmem (or, in the case of SuSE, dom0).
>> And even if a guest does enable tmem, the problem manifested
>> largely due to shadow pages using order>0 (now fixed?)...
>> failure on domain creation can happen for many reasons and
>> is much less of an issue, true?
>>
>> Feel free to shoot me down with more evidence, but I have
>> to at least provide token resistance to this patch.  Distros
>> might certainly choose to disable it to avoid any risk at
>> all, but turning it off anymore seems overkill for xen.org
>> open source Xen IMHO.
>
> Tbh I was wondering whether anyone is really using it in earnest. No
> upstream kernels support it? If noone's using it, who really cares whether
> it's enabled or not, apart from its author.
>
>   -- Keir
>


Well, it is present but disabled in the new Debian Squeeze kernel... and 
as there is no documentation, there is no chance to see it enabled.

I had to search on the xen lists to find how to enable that.

For example :
http://www.google.fr/search?hl=fr&source=hp&q=tmem_compress

We should maybe add info about tmem on the Xen Wiki, no ?

Olivier