{HEAD ~ Blockers} are responsible for blocking {TAIL ~ new request} for a cache line until an outstanding request for that cache line has been serviced 
are responsible for blocking
{ HEAD ~ Blockers } are responsible for blocking { TAIL ~ new request } for a cache line until an outstanding request for that cache line has been serviced
HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH