Re: [Xen-users] Dom0 seeing 2Gb, but not 4GB ram

[Mark Lassiter <mackdaddylassiter@xxxxxxxxx>]

I'm sorry, I did mean to CC everyone.
In fact, I sent another message with the log file and
bios information you suggested and did the same thing
:) <== dork.

I pasted it below again.  I have since recompiled with
PAE support and it works!

Only problem was that I had to manually edit the
Config.mk file in the root of the xen source tree and
specify the XEN_TARGET_X86_PAE ?= y (was n).
The instructions  (README) indicate that I only need
to run menuconfig from the xen0 and xenU source
directories, but apparently this is necessary,
otherwise you get an error about xen and dom0 PAE mode
mismatch on boot.
I can now see all 4GB.

I still wonder why I can't with CONFIG_HIGHMEM4G? 
Perhaps something along the lines of the PAE config
problem above whereby the xen kernel is not actually
being built with the same options as dom0 and domU?
Perhaps I'm misreading the README on  building the
dist.

Anyhow, my BIOS log entries from the previous
(misaddressed) email:

>From Fedora4 SMP Kernel
=======================
Nov  9 19:02:03 localhost kernel: Linux version
2.6.13-1.1532_FC4smp
(bhcompile@xxxxxxxxxxxxxxxxxxxxxxx) (gcc version 4.0.1
20050727 (Red Hat 4.0.1-5)) #1 SMP Thu Oct 20 01:51:51
EDT 2005
Nov  9 19:02:03 localhost kernel: BIOS-provided
physical RAM map:
Nov  9 19:02:03 localhost kernel:  BIOS-e820:
0000000000000000 - 000000000009f400 (usable)
Nov  9 19:02:03 localhost kernel:  BIOS-e820:
000000000009f400 - 00000000000a0000 (reserved)
Nov  9 19:02:03 localhost kernel:  BIOS-e820:
00000000000e0000 - 0000000000100000 (reserved)
Nov  9 19:02:03 localhost kernel:  BIOS-e820:
0000000000100000 - 0000000080000000 (usable)
Nov  9 19:02:03 localhost kernel:  BIOS-e820:
00000000ff780000 - 0000000100000000 (reserved)
Nov  9 19:02:03 localhost kernel:  BIOS-e820:
0000000100000000 - 0000000180000000 (usable)
Nov  9 19:02:03 localhost kernel: 5248MB HIGHMEM
available.
Nov  9 19:02:03 localhost kernel: 896MB LOWMEM
available.
Nov  9 19:02:03 localhost kernel: found SMP MP-table
at 000ff780

>From Xen:
==================
Nov  9 19:07:45 localhost kernel: Linux version
2.6.12.6-xen0 (root@xxxxxxxxxxxxxxxxxxxxx) (gcc
version 4.0.1 20050727 (Red Hat 4.0.1-5)) #2 SMP Wed
Nov 9 09:00:37 EST 2005
Nov  9 19:07:45 localhost kernel: BIOS-provided
physical RAM map:
Nov  9 19:07:45 localhost kernel:  Xen:
0000000000000000 - 00000000765c0000 (usable)
Nov  9 19:07:45 localhost kernel: 1069MB HIGHMEM
available.
Nov  9 19:07:45 localhost kernel: 832MB LOWMEM
available.
Nov  9 19:07:45 localhost kernel: found SMP MP-table
at 000ff780



--- Mark Williamson <mark.williamson@xxxxxxxxxxxx>
wrote:

> Did you mean to cc the list on that last e-mail? 
> Probably worthwhile...
> 
> Anyhow, it might be nice to compare the memory map
> output in dmesg between 
> your different configurations...  Native Linux's
> "dmesg" output and Xen's "xm 
> dmesg" output should give us what we need here.
> 
> Usually when people are missing lots of accessible
> memory it's because the 
> BIOS has reserved excessive amounts of physical
> address space under 4Gig for 
> IO device registers...  I've never heard of an
> entire 2 gig disappearing on 
> it, though...  Anyhow, *if* it turns out to be that,
> the solution is to use 
> something that can address above 4Gig: either PAE or
> 64-bit mode.
> 
> Hopefully we can find something that suits.
> 
> Cheers,
> Mark
> 
> On Wednesday 09 November 2005 21:30, you wrote:
> > Thanks for your response.
> >
> > The 64 bit problems resulted in Kernel panics:
> failed
> > to sync.  I can elaborate further, but would
> prefer to
> > do so in another thread.  I'll keep this one
> focused
> > on not seeing 4GB.
> >
> > I'll try checking my kernel for PAE and see if
> that
> > option works.  Perhaps that's all I need.  It is
> > wierd.
> >
> > What I did:
> >
> > 1.  Installed FC4-32.
> > 2.  yum -y update
> > 3.  Installed xen via yum and following the Redhat
> > QuickStart.  Could only see 2Gb.
> > 4.  Removed the xen packages and downloaded latest
> > source (unstable).
> > 5.  make world
> > 6.  Ran the menuconfig in both the xen0 and xenU
> > source directories, setting the HIGHMEM4G option.
> > 7.  Also selected the Operaton processor for my
> target
> > processor.
> > 8.  make dist
> > 9.  make install
> > 10. ran mkinitrd and created an image.
> > 11. Configured grub.conf
> > 12. Booted Xen dom0.  Ran free and only see 2Gb.
> >
> > Am I missing something?
> >
> >
> >
> > --- Mark Williamson <mark.williamson@xxxxxxxxxxxx>
> >
> > wrote:
> > > > The core linux installation is Fedora Core
> > >
> > > 4-32bit.
> > >
> > > > FC4 sees all 4GBs of RAM.  The Xen Dom0,
> however,
> > >
> > > only
> > >
> > > > sees 2Gb.
> > > >
> > > > I've tried the following:
> > > > 1. Installing the pre-built FC4 Xen Kernels. 
> Same
> > > > result.
> > > > 2. Installing the FC4-64bit.  Could then see
> 4GB,
> > >
> > > but
> > >
> > > > ran into other issues creating a guest system.
> > >
> > > OK...?  Xen on 64 bit ought to work reasonably
> well.
> > >  Was it a Xen problem or
> > > an FC4 problem that stopped you?  If the former
> was
> > > the case (and it's not
> > > fixed yet) you should probably scream about it
> ;-)
> > >
> > > > 3. Downloading the latest Xen-unstable code,
> using
> > > > menuconfig to set ensure the CONFIG_HIGHMEM4G
> > >
> > > setting
> > >
> > > > was set (and it is) and building new kernels
> to
> > > > FC4-32.
> > >
> > > That sounds like it ought to work...
> > >
> > > > The last is where I stand today.  For some
> reason,
> > > > however, I only see 2GB of RAM.  That fact
> that I
> > >
> > > see
> > >
> > > > 2GB leads me to believe the HIGHMEM is working
> > > > (because it would be 800Mb otherwise, right?).
> > >
> > > Why
> > >
> > > > can't I see the rest?  Could it have to do
> with
> > >
> > > having
> > >
> > > > 2x2Gb sticks instead of 4x1Gb?
> > > >
> > > > I don't believe I can use PAE, thats an intel
> > >
> > > thing,
> > >
> > > > right?
> > >
> > > It should work on Opteron AFAIK.
> > >
> > > What you're seeing seems pretty weird... can you
> > > check your normal kernel
> > > definitely isn't using PAE?  I guess it's
> possible
> > > you need PAE to see all
> > > your memory, but "losing" 2Gig seems just
> bizarre to
> > > me.
> > >
> > > I'm not familiar with what Fedora supports by
> > > default.  Maybe someone from
> > > Redhat can comment.
> > >
> > > > I'm at a loss.  We really want to make use of
> our
> > > > memory as we plan to run one DomU with 1GB and
> the
> > > > rest with 512GB each.
> > > >
> > > > The Xen kernel version is 2.6.12.6 (unstable).
>  FC
> > >
> > > has
> > >
> > > > all the latest yum updates as of this morning.
> > >
> > > It ought to work as you want...
> > >
> > > Cheers,
> > > Mark
> > >
> > > _______________________________________________
> > > Xen-users mailing list
> > > Xen-users@xxxxxxxxxxxxxxxxxxx
> > > http://lists.xensource.com/xen-users
> >
> > __________________________________
> > Yahoo! Mail - PC Magazine Editors' Choice 2005
> > http://mail.yahoo.com
> 



        
                
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