Sumanesh, > Instead of relying on QUEUE_FULL and some complex heuristics of when > to start tracking device_busy, why can't we simply use " > track_queue_depth" ( along with the other flag that Ming added) to > decide which devices need queue depth tracking, and track device_busy > only for them? Because I am interested in addressing the device_busy contention problem for all of our non-legacy drivers. I.e. not just for controllers that happen to queue internally. > I am not sure how we can suddenly start tracking device_busy on the fly, > if we do not know how many IO are already pending for that device? We know that from the tags. It's just not hot path material. -- Martin K. Petersen Oracle Linux Engineering
