[SOLVED] Memory hotplug and ballooning problem 919 MB max memory

[svirus]

Hi,

I have a problem with ubuntu-cloud template in proxmox.
When I have enabled hotplug, enabled NUMA, ballooning enabled and Memory and Minimum memory set to same value (i.e. to 8192) always can't have more than 919MB on system.
When I try alloc more, then OOMKIller starting
qemu-guest-agent installed
# info balloon
balloon: actual=8192 max_mem=8192 total_mem=919 free_mem=16 last_update=1680854141

Proxmox 7.4-3
Ubuntu 22.04 LTS

I mieesed something?

When I disable Memeory hotplug then system can normal boot with 8192 MB memory.


Thanks in advaned

 

[dcsapak]

did you read: https://pve.proxmox.com/wiki/Hotplug_(qemu_disk,nic,cpu,memory)#Linux_Guests_Notes

the guest must be configured in a way to automatically use the hotplugged memory modules

 

[svirus]

Yes, I added this:
SUBSYSTEM=="cpu", ACTION=="add", TEST=="online", ATTR{online}=="0", ATTR{online}="1"


still have 919MB and when I try to alloc more then OOMKiller start

 

[dcsapak]

did you add the 'memhp_default_state=online' to the kernel commandline?

 

[svirus]

OK
I added memhp to GRUB_CMD_LINUX
But on https://pve.proxmox.com/wiki/Hotplug_(qemu_disk,nic,cpu,memory)#Linux_Guests_Notes is infor about to add only to udev if kernel is >= 5.15
My kernel is 5.15.0-1030-kvm

 

[dcsapak]

so does it work now or not?

maybe the wording is not optimal in the wiki page, if i have time, i can check it here

 

[svirus]

Yes, it working now.
On wiki is "For Linux kernel >=5.15 (e.g. Ubuntu 22.04) you only need the UDEV rule for cpu hotplug"
But I must also add memhp to boot command line... so in wiki is unclear information.