Memory usage overstated when passing through GPU

[kosielemmer]

Hi.

I have an issue where the dashboard says one of my vms consume 100% (or more ) of the ram allocated but when I run TOP consumption is much lower. ANybody any ideas or files I should share. I am passing a GPU through. It is an Ubuntu server/

Conf file below:


agent: 1,fstrim_cloned_disks=1
balloon: 0
bios: ovmf
boot: order=scsi0
cipassword:
ciuser:
cores: 8
cpu: host
efidisk0: local-zfs:vm-102-disk-1,efitype=4m,pre-enrolled-keys=1,size=1M
hostpci0: 0000:07:00,pcie=1,x-vga=1
ide2: local-zfs:vm-102-cloudinit,media=cdrom,size=4M
ipconfig0: ip=192.168.1.15/24,gw=192.168.1.1
machine: q35
memory: 8192
meta: creation-qemu=10.0.2,ctime=1762224263
name: vm102
net0: virtio=BC:24:11:7B:CC:35,bridge=vmbr0
numa: 0
onboot: 1
ostype: l26
scsi0: local-zfs:vm-102-disk-0,size=5123584M
scsihw: virtio-scsi-pci
serial0: socket
smbios1: uuid=
snaptime: 1762610320
sockets: 1
sshkeys
vga: virtio
vmgenid:

 

[leesteken]

This is normal when using PCI(e) passthrough.

Post in thread 'Very high memory usage on VM'

Feb 3, 2024

As always with PCI(e) passthrough, all VM memory must be pinned into actual host memory because of possible DMA. There is no way around that, so it does not matter what the GUI shows, all of the VM memory is used all the time while the VM is running (or being backed up).

• leesteken

• 

Post in thread 'PCIe passthrough'

May 14, 2021

Just a side note: My VMs would consume 1/2 of the available RAM if each VM uses 100 % of the granted RAM

Please be aware that PCI(e) passthrough requires local all VM memory into actual RAM. The PCIe devices can do DMA at any time and ballooning/sharing memory that can be changed without notice is not possible. Therefore in your case, both VMs will use at least 100% of the memory set in their configuration.

• leesteken

EDIT: Remove balloon: 0 if you want Proxmox to show the "memory usage" from within the VM.

 

[kosielemmer]

This is normal when using PCI(e) passthrough.

Post in thread 'Very high memory usage on VM'

Feb 3, 2024

As always with PCI(e) passthrough, all VM memory must be pinned into actual host memory because of possible DMA. There is no way around that, so it does not matter what the GUI shows, all of the VM memory is used all the time while the VM is running (or being backed up).

• leesteken

• 

Post in thread 'PCIe passthrough'

May 14, 2021

Just a side note: My VMs would consume 1/2 of the available RAM if each VM uses 100 % of the granted RAM

Please be aware that PCI(e) passthrough requires local all VM memory into actual RAM. The PCIe devices can do DMA at any time and ballooning/sharing memory that can be changed without notice is not possible. Therefore in your case, both VMs will use at least 100% of the memory set in their configuration.

• leesteken

EDIT: Remove balloon: 0 if you want Proxmox to show the "memory usage" from within the VM.

Thanks very much