Subject: xennetback_ifstart: no mcl_pages crashes XEN2-dom0
To: None <firstname.lastname@example.org>
From: Damian Lubosch <email@example.com>
Date: 05/30/2007 19:39:34
I am using NetBSD4.0Beta as XEN2-Dom0 (from 10/4/06) with six
NetBSD3.0.1 DomUs on an AMD 3700+ server, VIA Chipset with 1GB of RAM
and Hardware Raid.
From time to time I get the following error that forces me to reboot my
May 30 10:07:42 pless /netbsd: xennetback: got only 29 new mcl pages
May 30 10:07:47 pless /netbsd: xennetback: got only 9 new mcl pages
May 30 10:07:48 pless /netbsd: xennetback: got only 3 new mcl pages
May 30 10:07:48 pless /netbsd: xennetback: got only 1 new mcl pages
May 30 10:07:48 pless /netbsd: xennetback: can't get new mcl pages (0)
May 30 10:07:48 pless /netbsd: xennetback_ifstart: no mcl_pages
And the last two lines repeat 1000+ times....
What are those mcl pages?
On the domU machines I let run a lot of RSync cronjobs copying files
from another sibling-PC with very similar configuration. Some of the
DomUs share directories with nfs. In fact this machine is my
hot-standby-backup-server. The master server does not complain about
this problem. (It only complains about ..."/netbsd: xbdback: domain 6
sending excessively fragmented I/O" but it's not that bad I think)
First I thought that it could have to do with a buggy network driver for
the onboard Realtec NIC but now there is an Intel NIC built in and the
problem still persists.
My system memory is divided as follows:
pless# xm list
Name Id Mem(MB) CPU State Time(s) Console
Domain-0 0 63 0 r---- 499.4
ap-php4 3 255 0 -b--- 26.0 9603
ap-php5 4 127 0 -b--- 21.8 9604
dbserver 5 127 0 -b--- 101.3 9605
mailserver 7 169 0 -b--- 60.5 9607
ns1 2 127 0 -b--- 20.4 9602
router 1 127 0 -b--- 257.4 9601
pless# xm info
system : NetBSD
host : pless
release : 4.0_BETA
version : NetBSD 4.0_BETA (XEN2_DOM0) #0: Wed Apr 18
15:14:53 CEST 2007 root@pless:/xen/usr/src/sys/arch/i386/compile/XEN2_DOM0
machine : i386
cores : 1
hyperthreads_per_core : 1
cpu_mhz : 2199
memory : 1022
free_memory : 2
I use an self-built kernel for this NetBSD version with more SHM pages
(8192 instead of 2048). I hoped that could solve the problem but it did not.
options SHMMAXPGS=8192 # 2048 pages is the default
I read on the list something about XEN-DOM0 needing 32MB for itself.
(Date of posting: 4/15/2005 6pm from Manuel Bouyer) Does it mean that I
have to increase my 2MB of free memory to 32? That's actually what I'd
Another idea which will be quite time consuming and I would like to avoid:
Is it worth it to update to a newer Beta-version of NetBSD4 with a newer
I really hope that there is somebody out there who can help me ;-)
Thanks in advance!