[pve-devel] balloon bug in qemu 2.1 ?

Alexandre DERUMIER aderumier at odiso.com
Thu Mar 5 16:17:49 CET 2015


ok,I speak too fast.
It's not related to this patch.


on current pve-qemu-kvm 2.1.

balloon is working fine
# info balloon
balloon: actual=1024 max_mem=1024 total_mem=1002 free_mem=941 mem_swapped_in=0 mem_swapped_out=0 major_page_faults=120 minor_page_faults=215272 last_update=1425568324


But if the vm (qemu 2.1) is started with
 -machine type=pc-i440fx-2.1
or 
 -machine type=pc-i440fx-2.0   (this is the case when you do a live migration)

It's not working

# info balloon
balloon: actual=1024 max_mem=1024



@Andrew, are your vm where you see the info balloon bug, have been migrated from old proxmox (without stop/start ?)
can you check in ssh if the kvm process have -machine type in the command line ?


----- Mail original -----
De: "aderumier" <aderumier at odiso.com>
À: "Andrew Thrift" <andrew at networklabs.co.nz>
Cc: "pve-devel" <pve-devel at pve.proxmox.com>
Envoyé: Jeudi 5 Mars 2015 16:05:03
Objet: Re: [pve-devel] balloon bug in qemu 2.1 ?

I need to do more tests, 

but it seem that this commit (applied on qemu 2.2 but not on qemu 2.1) 
http://git.qemu.org/?p=qemu.git;a=commit;h=22644cd2c60151a964d9505f4c5f7baf845f20d8 

fix the problem with qemu 2.1. 
(I have tested with the patch, balloon works fine, I need to test without the patch to compare) 





----- Mail original ----- 
De: "aderumier" <aderumier at odiso.com> 
À: "Andrew Thrift" <andrew at networklabs.co.nz> 
Cc: "pve-devel" <pve-devel at pve.proxmox.com> 
Envoyé: Jeudi 5 Mars 2015 15:41:51 
Objet: Re: [pve-devel] balloon bug in qemu 2.1 ? 

in proxmox virtio-balloon-fix-query.patch, 

we have 

hw/virtio/virtio-balloon.c 

+ 
+ if (!(balloon_stats_enabled(dev) && balloon_stats_supported(dev) && 
+ dev->stats_last_update)) { 
+ return; 
+ } 
+ 
+ info->last_update = dev->stats_last_update; 
+ info->has_last_update = true; 
+ 
+ info->mem_swapped_in = dev->stats[VIRTIO_BALLOON_S_SWAP_IN]; 
+ info->has_mem_swapped_in = info->mem_swapped_in >= 0 ? true : false; 
+ 
+ info->mem_swapped_out = dev->stats[VIRTIO_BALLOON_S_SWAP_OUT]; 
+ info->has_mem_swapped_out = info->mem_swapped_out >= 0 ? true : false; 
+ 
+ info->major_page_faults = dev->stats[VIRTIO_BALLOON_S_MAJFLT]; 
+ info->has_major_page_faults = info->major_page_faults >= 0 ? true : false; 
+ 
+ info->minor_page_faults = dev->stats[VIRTIO_BALLOON_S_MINFLT]; 
+ info->has_minor_page_faults = info->minor_page_faults >= 0 ? true : false; 
+ 


so, that mean that in qemu 2.1 

+ if (!(balloon_stats_enabled(dev) && balloon_stats_supported(dev) && 
+ dev->stats_last_update)) { 
+ return; 
+ } 

one of this 3 funtions is not working 


----- Mail original ----- 
De: "Andrew Thrift" <andrew at networklabs.co.nz> 
À: "aderumier" <aderumier at odiso.com> 
Cc: "pve-devel" <pve-devel at pve.proxmox.com> 
Envoyé: Jeudi 5 Mars 2015 15:17:58 
Objet: Re: [pve-devel] balloon bug in qemu 2.1 ? 

Hi Alexandre, 
This may be the cause of the crashes we have been experiencing. We reported them here: 

http://forum.proxmox.com/threads/21276-Kernel-Oops-Panic-on-3-10-5-and-3-10-7-Kernels 

These only started happening since we moved to qemu-2.1.x and we get the same output: 

# info balloon 
balloon: actual=16384 max_mem=16384 

and have noticed VM's with only 1-2GB usage in the guest reporting almost the entire amount of ram used to the host, even though we have the latest balloon driver loaded and the blnsvr.exe service running. 



On Thu, Mar 5, 2015 at 11:33 PM, Alexandre DERUMIER < aderumier at odiso.com > wrote: 


Hi, 

I have see a bug report here: 
http://forum.proxmox.com/threads/21111-RAM-Problem-since-Upgrade-to-3-4?p=108367&posted=1#post108367 

about balloon. 


on my qemu 2.2 

#info balloon 
balloon: actual=1024 max_mem=2048 total_mem=985 free_mem=895 mem_swapped_in=0 mem_swapped_out=0 major_page_faults=301 minor_page_faults=61411 last_update=1425550707 


same vm with qemu 2.2 + "-machine type=pc-i440fx-2.1" 
#info balloon 
balloon: actual=1024 max_mem=2048 



(Don't have true qemu 2.1 for test currently) 


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