[pve-devel] [PATCH container 13/20] cgroup: add change_cpu_quota, change_cpu_shares

[Thomas Lamprecht]

On 4/3/20 4:37 PM, w.bumiller at proxmox.com wrote:
> ...
> +# Change the cpu "shares" for a container.
> +#
> +# In cgroupv1 we used a value in `[0..500000]` with a default of 1024.
> +#
> +# In cgroupv2 we do not have "shares", we have "weights" in the range
> +# of `[1..10000]` with a default of 100.
> +#
> +# Since the default values don't match when scaling linearly, we use the
> +# values we get as-is and simply error for values >10000 in cgroupv2.
> +#
> +# It is left to the user to figure this out for now.
> +#
> +# Dies on error (including a not-running or currently-shutting-down guest).
> +sub change_cpu_shares {
> +    my ($self, $shares, $cgroupv1_default) = @_;
> +
> +    if (cgroup_mode() == 2) {
> +	if (defined(my $path = $self->get_path('cpu'))) {
> +	    # the cgroupv2 documentation defines the default to 100
> +	    $shares //= 100;
> +	    die "cpu weight (shares) must be in range [1, 10000]\n" if $shares < 1 || $shares > 10000;

Wouldn't it be more sensible to existing setup when this just truncates those
values which where valid for cgroupv1? I.e. >1000 -> 1000 and < 1 -> 1?