| |
|
 |
|
 |
|
|
|
| |
|
|
xen-devel
RE: [Xen-devel] failed to start centos 5 domU with maxmem=30000
> From: Vasiliy G Tolstov [mailto:v.tolstov@xxxxxxxxx]
> Sent: Thursday, August 12, 2010 5:38 AM
> To: Pasi Kärkkäinen
> Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Xen-devel] failed to start centos 5 domU with
> maxmem=30000
>
> В Чтв, 12/08/2010 в 14:37 +0300, Pasi Kärkkäinen пишет:
> > On Thu, Aug 12, 2010 at 02:24:05PM +0400, Vasiliy G Tolstov wrote:
> > > Hello. I'm try to start centos domU pvm under sles 11 sp1 xen
> kernel
> > > with memory=512 and maxmem=30000. Centos doing boot and freeze.
> > > If i'm try to use maxmem=15000 all works.
> > >
> > > Can You tell me what's wrong?
> > >
> >
> > Is the centos PV domU 32bit or 64bit ?
>
> 64 bit kernel-xen.
>
> I found this in xen sources:
>
> /* Simple continuous piecewiese linear function:
> * max MiB -> min MiB gradient
> * 0 0
> * 16 16
> * 32 24
> * 128 72 (1/2)
> * 512 168 (1/4)
> * 2048 360 (1/8)
> * 8192 552 (1/32)
> * 32768 1320
> * 131072 4392
> */
>
> Why this is not provided in documentation or on web site?
Hi Vasily --
This function limits how far memory can be reduced when
ballooning a guest (including dom0). It is only a heuristic
but is intended to take into account the various overheads
a guest Linux kernel requires to manage memory to avoid
out-of-memory conditions.
But I think you are correct... the same (or similar)
function should be published as it also serves as a
guideline for the ratio between memory= and maxmem=
parameters when creating a guest: If the ratio
of maxmem divided by memory is too high, the guest
will not even boot.
I am curious as to why you would specify memory= so
much smaller than maxmem=. Are you trying to overcommit
memory for guests that are often idle but sometimes use
a very large amount of memory?
Thanks,
Dan
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
|
|
| |
|
Home