xen_balloon: reserve_additional_memory: add_memory() failed:

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bshoe24
Posts: 22
Joined: 2015/03/11 15:38:54

xen_balloon: reserve_additional_memory: add_memory() failed:

Post by bshoe24 » 2015/05/05 14:51:11

Hi,

My logs are flooded with the following Xen messages repeating. I had already disabled Xen memory auto-ballooning and there is plenty of memory available to Xen as i'm only running about 20 VPS on this node.

--
May 5 10:57:19 ny-host11 kernel: System RAM resource [mem 0x48000000-0x4fffffff] cannot be added
May 5 10:57:19 ny-host11 kernel: xen_balloon: reserve_additional_memory: add_memory() failed: -17
--

I searched and found this temp fix to silence the repeated log entries but, the problem persists.

http://marc.info/?l=xen-devel&m=135601507023322&w=1

--

Here are the relevant settings i'm using.

/boot/grub/grub.conf
kernel /xen.gz dom0_mem=1024M,max:1024M

/etc/xen/xl.conf
autoballoon=0

/etc/xen/xend-config.sxp
(dom0-min-mem 1024)
(enable-dom0-ballooning no)

--

[root@host11 ~]# xl info
host : host11.xxxxxxx.net
release : 3.10.68-11.el6.centos.alt.x86_64
version : #1 SMP Fri Feb 6 10:40:16 CST 2015
machine : x86_64
nr_cpus : 6
max_cpu_id : 5
nr_nodes : 1
cores_per_socket : 6
threads_per_core : 1
cpu_mhz : 2400
hw_caps : bfebfbff:2c100800:00000000:00007f00:75fefbff:00000000:00000021:000037ab
virt_caps : hvm hvm_directio
total_memory : 32661
free_memory : 16670
sharing_freed_memory : 0
sharing_used_memory : 0
outstanding_claims : 0
free_cpus : 0
xen_major : 4
xen_minor : 4
xen_extra : .1-10.el6
xen_version : 4.4.1-10.el6
xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64
xen_scheduler : credit
xen_pagesize : 4096
platform_params : virt_start=0xffff800000000000
xen_changeset : Wed Oct 15 15:36:23 2014 +0100 git:5c9cb6d-dirty
xen_commandline : dom0_mem=1024M,max:1024M loglvl=all guest_loglvl=all
cc_compiler : gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-11)
cc_compile_by : mockbuild
cc_compile_domain : centos.org
cc_compile_date : Wed Apr 1 14:16:00 UTC 2015
xend_config_format : 4
[root@host11 ~]#


Does anyone know a fix for this or is this a known bug that i have to wait for an update for?

Thank you

aks
Posts: 3073
Joined: 2014/09/20 11:22:14

Re: xen_balloon: reserve_additional_memory: add_memory() fai

Post by aks » 2015/05/05 16:50:39

Does the work around (in the link you posted) work?
I.e.: if you set XEN's target memory to the current use, does that prevent the messages?

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bshoe24
Posts: 22
Joined: 2015/03/11 15:38:54

Re: xen_balloon: reserve_additional_memory: add_memory() fai

Post by bshoe24 » 2015/05/05 17:48:46

Hi,

Yes it does silence it for a few days but, it seems to start again after few days and i have to go run that command again. I've just started doing that so I am still monitoring it on several Xen servers i manage.

I found in my google searches that this issue was in previous version of Xen. I'm fully updated to Xen4.4.1-10. I had recently converted to XL Toolstack and i've started seeing it since around then but, it could be coincidental with that and actually from a recent Xen update too.

I'm really not sure where it's come from.

aks
Posts: 3073
Joined: 2014/09/20 11:22:14

Re: xen_balloon: reserve_additional_memory: add_memory() fai

Post by aks » 2015/05/05 18:00:58

So I read that as though the balloon is inflating, which means ballooning is still active. The current and target values will change over time (depending on memory pressure across the node), which fits with the works for some time.
I thought you had to set autoballoon = off (not 0 - and default is auto).
Could be wrong, just my 2 cents...

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bshoe24
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Re: xen_balloon: reserve_additional_memory: add_memory() fai

Post by bshoe24 » 2015/05/05 21:03:13

Hi,

I had read that about the "off" but, i also read this http://wiki.xenproject.org/wiki/Xen_Pro ... _Practices where it says autoballoon=0 so i'm not sure if both are ok or just "off".

I am going to switch a couple servers in next maintenance window to "off" to see if it makes a difference.

Thanks for the suggestion

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bshoe24
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Re: xen_balloon: reserve_additional_memory: add_memory() fai

Post by bshoe24 » 2015/05/12 19:27:17

Following up on this i made that autoballoon="off" change to the config to test and rebooted 3 servers and it didn't make any difference.

Xen 4.4.1-10.el6 floods the logs with the following even though i've turned off memory ballooning. The servers have plenty of memory available.

May 12 19:44:26 london-host10 kernel: System RAM resource [mem 0x48000000-0x4fffffff] cannot be added
May 12 19:44:26 london-host10 kernel: xen_balloon: reserve_additional_memory: add_memory() failed: -17

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bshoe24
Posts: 22
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Re: xen_balloon: reserve_additional_memory: add_memory() fai

Post by bshoe24 » 2015/05/13 18:18:21

It looks like this is the known bug6893 mentioned on this page. http://wiki.centos.org/HowTos/Xen/Xen4QuickStart

I actually had seen that page a long while back but, forgot about it. As i was running XM Toolstack still i never saw the bug until now that i have converted servers to XL Toolstack.

Next maintenance window i am going to make that "dom0_mem=1024M,max:1536M" change to a couple servers to test and hopefully be able to silence this.

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