[pve-devel] [PATCH v2 qemu-server 5/6] start: handle pool limits

[Daniel Kral]

On 16/04/2024 14:20, Fabian Grünbichler wrote:
> if the start is not part of an incoming migration, check the VM against its
> pool's run limit.
> 
> Signed-off-by: Fabian Grünbichler <f.gruenbichler at proxmox.com>
> ---
>  PVE/QemuServer.pm | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
> index be937ec1..78b6ff96 100644
> --- a/PVE/QemuServer.pm
> +++ b/PVE/QemuServer.pm
> @@ -5704,6 +5704,19 @@ sub vm_start_nolock {
>  	    # But we do it above, so for now let's be consistent.
>  	    $conf = PVE::QemuConfig->load_config($vmid); # update/reload
>  	}
> +
> +	my $cpu_count = 1;
> +	$cpu_count = $conf->{sockets} if $conf->{sockets};
> +	$cpu_count *= ($conf->{cores} || 1);
> +	$cpu_count = $conf->{vcpus} if $conf->{vcpus} && $conf->{vcpus} < $cpu_count;
> +
> +	my $changes = {
> +	    absolute => 1,
> +	    running => 1,
> +	    mem => get_current_memory($conf->{memory}),

Bug: The memory value here should be converted from MiB to bytes, else
the pool limit will not be enforced as `check_guest_pool_limit` expects
the value to be in bytes, i.e. `get_current_memory(...) * 1024 * 1024`.

Spotted it by starting a second VM (which would've raised the memory
usage over the limit) and wondered why it didn't fail. For the third VM
I got:

```
pool limits exhausted: (run) mem: 4096 + 0.001953125 over 3072
```

> +	    cpu => $cpu_count,
> +	};
> +	PVE::GuestHelpers::check_guest_pool_limit($vmid, $changes);
>      }
>  
>      # override offline migrated volumes, conf is out of date still
> -- 
> 2.39.2