this is just to inform you that the cgroups interface for controlling I/O through weights (blkio.weight, blkio.weight_device and io.weight files) was changed some years ago. In particular, weight_device does not exist any longer, while the *.weight parameters are not connected to the proportional-share policy any longer. The actual parameters to use are blkio.bfq.weight and io.bfq.weight.
In the last two years, I’ve been working to get this confusing situation fixed, i.e., to make the weight interface back as before. But still at no avail . I don’t know whether and when I’ll make it.
In the meantime, be aware that no I/O control is performed by Docker through weights. If this is a concern for you, I’m willing to help make Docker comply with the current state of affairs.