Hi Paolo, I am reading the code of BFQ scheduler and having a question about the purpose of idle rb-tree in bfq_service_tree.
>From the comment in code, the idle rb-tree is used to keep the bfq_queue which doesn't have any request and has a finish time greater than the vtime of the service tree. The only function that I can find and reveals the purpose of the idle rb-tree is __bfq_activate_entity(). In this function, when the activated queue had been on the idle tree, the start time of the queue will be reset to the greater value between min_vstart and finish time. It seems to me that the idle rb-tree is used to delay the schedule of the queue which issues requests periodically, but I don't known why the delay is needed. Could you please explain the purpose of the idle rb-tree in bf_service_tree and its main scenario ? Thanks, Tao
