[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: [Xen-users] Maximal RAM reservation for Linux-Dom0

Well, the Xen kernel itself will use some memory, and there may be
"holes" in the memory too (for example for ISA/BIOS space just under
1MB), so if you've got 512MB of memory in your machine, I don't expect
you to be able to give 512MB to the Dom0. 

I'm not sure how much memory the Xen kernel uses, the code in the kernel
itself is about 3-400KB, 24KB of initialized data and 128KB of BSS, so a
good half a megabyte, but it will also allocate/reserve some other
memory areas, which I'm sure will amount to a fair bit more. For
instance, in the mm.c, there's a single allocation of 4MB for a
"mapcache". There are also many small allocations through xmalloc, that
build up to some amount of memory usage. How big that is, I can't really
estimate, because it's too many places to easily and quickly understand
what gets run how many times, etc. 

> -----Original Message-----
> From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx 
> [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of 
> Subhabrata Bhattacharya
> Sent: 10 August 2005 10:20
> To: Jean-Christophe Guillain
> Cc: xen-users@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Xen-users] Maximal RAM reservation for Linux-Dom0
> > > If you don't intend to run any guest domains on the host, 
> I don't see why  you can't use your whole memory for dom0...
> I don't see the reason too but on allocation, I find Xen 
> Domain 0 spitting up cannot allocate enough memory for Domain 
> 0 reservation [something of that sort]
> > > But why do you want to use an Xen kernel in this case ?
> Just out of curiosity :)
> > But I think that it would be interesting to know how to 
> calculate the amount of memory we can't allocate to any 
> domain when we have several ones running (xen0 + xenUs)...
> > What it depends on ?
> Yeah I jibe with this.
> ~$ubh
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users

Xen-users mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.