Only support around 16 containers to specify RDT cache requirement

[linericyang]

Current runc will create a dedicated RDT Class of Service (CLOS) for each running container, even they have exactly same Scheam. This will lead to short of CLOS, since there is a hardware limit for the number of CLOS, around 16 CLOS per platform. This mean it only can support 16 containers to specify cache requirements, and it will generate error if it exceeds that number.

This proposal is add one parameter 'closID' to allow user to specify which RDT Class of Service (CLOS) the container will be located. So it can place these containers with same Schema into one single CLOS.

The corresponding PR to OCI spec is here.

[xiaochenshen]

FYI - The hardware limit for number of CLOS (or RDT control groups) is exported through /sys/fs/resctrl/info/L3/num_closids

[linericyang]

@hqhq Thanks a lot for reviewing the opencontainers/runtime-spec#988. Seems this issue has been automatically closed after that OCI spec got merged. I cannot re-open it because it was not closed by me. Is it possible you re-open this issue? We will submit patches to runc repo to implement the spec change.