Bug 489876 – kernel option dom0_mem doesn't work

Bug 489876 - kernel option dom0_mem doesn't work

Summary:	kernel option dom0_mem doesn't work

Status:	CLOSED NOTABUG

Aliases:	None

Product:	Red Hat Enterprise Linux 5
Classification:	Red Hat
Component:	kernel-xen (Show other bugs)
Sub Component:
Version:	5.3
Hardware:	All Linux

Priority	medium Severity medium
Target Milestone:	rc
Target Release:	---
Assigned To:	Rik van Riel
QA Contact:	Red Hat Kernel QE team
Docs Contact:

URL:
Whiteboard:
Keywords:

Depends On:
Blocks:
	Show dependency tree / graph

Reported:	2009-03-12 09:17 EDT by Daniel Mach
Modified:	2009-03-17 08:19 EDT (History)
CC List:	2 users (show)

See Also:
Fixed In Version:
Doc Type:	Bug Fix
Doc Text:
Story Points:	---
Clone Of:
Environment:
Last Closed:	2009-03-17 08:19:58 EDT
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

Attachments	(Terms of Use)
Add an attachment (proposed patch, testcase, etc.)

Groups: None (edit)

Description Daniel Mach 2009-03-12 09:17:43 EDT

I have this kernel option in grub.conf: dom0_mem=512m
After boot, dom0 allocates all memory instead of 512M.

It used to work in rhel-5.2.

As a workaround, I have to call:
$ xm mem-set Domain-0 512

Comment 1 RHEL Product and Program Management 2009-03-12 09:21:42 EDT

This bugzilla has Keywords: Regression.  

Since no regressions are allowed between releases, 
it is also being proposed as a blocker for this release.  

Please resolve ASAP.

Comment 3 Chris Lalancette 2009-03-12 10:09:19 EDT

Can you please attach the full output of the grub.conf entry that you think should work, but doesn't?

Thanks,
Chris Lalancette

Comment 4 Chris Lalancette 2009-03-12 10:16:55 EDT

FYI: on my system, the following does indeed do the right thing:

title Red Hat Enterprise Linux Server (2.6.18-134.el5virttest12xen)
	root (hd0,0)
	kernel /xen.gz-2.6.18-134.el5virttest12 dom0_mem=512M
	module /vmlinuz-2.6.18-134.el5virttest12xen ro root=/dev/VolGroup02/LogVol00
	module /initrd-2.6.18-134.el5virttest12xen.img

# xm list (right after boot)
Name                                      ID Mem(MiB) VCPUs State   Time(s)
Domain-0                                   0      512     4 r-----     27.8

Chris Lalancette

Comment 5 Daniel Mach 2009-03-17 08:19:58 EDT

Chris,
sorry for confusion,
I had the dom0_mem as a kernel (not xen) option in grub.conf.
Now everything works fine.

Since I didn't have xen dom0 ballooning problems for a long time so I thought that the "not enough memory" problems during `xm create` were caused by a kernel upgrade and therefore a regression.

Looks like I was just lucky and didn't hit this problem since 5.2 was released until now.

thanks,
- daniel

Note You need to log in before you can comment on or make changes to this bug.