Bug 121947

Summary:	Too much memory allocated to dom0 on 16gb x86_64 system
Product:	[openSUSE] SUSE Linux 10.1	Reporter:	Charles Duffy <ccd>
Component:	Xen	Assignee:	Jiri Srain <jsrain>
Status:	VERIFIED FIXED	QA Contact:	E-mail List <qa-bugs>
Severity:	Normal
Priority:	P5 - None
Version:	Alpha 1
Target Milestone:	---
Hardware:	x86-64
OS:	All
Whiteboard:
Found By:	Other	Services Priority:
Business Priority:		Blocker:	---
Marketing QA Status:	---	IT Deployment:	---

Description Charles Duffy 2005-10-10 12:14:41 UTC

By default, on my testbed system (2xCPU x86_64, 16GB RAM), YaST assigns
dom0_mem=16711680. However, that memory fails to be allocated on boot, and I
need to decrease it somewhat (thus far I've been decreasing it a full 1GB since
I don't need that much RAM for dom0) before the system will start properly.

Perhaps the hypervisor needs more space for its own purposes on such hardware?

Comment 1 Michael Gross 2005-10-10 13:21:15 UTC

Let's the maintainer decide.

Comment 2 Ladislav Slezák 2005-10-10 13:39:37 UTC

AFAIK XEN needs 64MB memory for itself. May be that the amount is dependent on
available memory size?

Michael, could you try to decrese the amount of the memory just slightly? (Let's
say 128MB or 256 MB for XEN itself.)

Gerd, could you comment that, please? How should yast propose the dom0 memory
size? (Currently it's total_size - 64MB.)

Comment 3 Gerd Hoffmann 2005-10-10 13:49:31 UTC

For SUSE Linux 10.1 (aka Xen 3.x) not specifying any dom0_mem= parameter should
do fine, xen will pick something reasonable then.

The 64 MB is address space, not physical memory btw.

Comment 4 Ladislav Slezák 2005-10-10 14:03:53 UTC

Oh, that's good that we do not have to use any extra kernel parameter any more.

Jiri, please remove dom0_mem option from proposed XEN section in bootloader
configuration.

Comment 5 Jiri Srain 2005-10-21 07:33:51 UTC

Done in SVN for 10.1.