CONFIG_BLK_DEV_THROTTLING not enabled on linux-vanilla but is on linux-virt breaks lxc-top

CONFIG_BLK_DEV_THROTTLING is not enabled on linux-vanilla but is on linux-virt.

CONFIG_BLK_DEV_THROTTLING cgroup can be used by the lxc package to provide disk throttling and is also by the lxc-top command to show I/O serviced reporting. https://github.com/lxc/lxc/blob/f8f1069a8d7e4a4d3d507a07df591ee9ebeb4737/src/lxc/tools/lxc_top.c#L284

When this is not present in the kernel, the output I/O columns of lxc-top are useless.

This only occurs when running the linux-vanilla kernel, whereas it works fine on linux-virt.

To test on a linux-virt host:

modprobe configs
zcat /proc/config.gz  | grep CONFIG_BLK_DEV_THROTTLING
CONFIG_BLK_DEV_THROTTLING=y
rmmod configs

It would be great if CONFIG_BLK_DEV_THROTTLING could be enabled on the linux-vanilla package as it is on the linux-virt package.

Thanks Tom