On Tue, 22 Sep 2015, Lakis, Jacek wrote:
> Hi ceph-devel!
> We're checking OSD::op_is_discardable condition two times: in dispatcher
> (handle_op) and in worker threads
> (do_request->can_discard_request->can_discard_op)
>
> if (!op->get_connection()->is_connected() &&
> op->get_version().version == 0) {
> return true;
> }
>
> Is there any purpose to do this? If not, which of those should be
> removed in your opinion? If condition in handle_op will remain, OP won't
> pass to the worker threads through the prioritized queue. On the other
> hand, leaving it in do_request will parallelize this check (I started
> parallelizing in PR 5211).
Is there a reason not to do it twice? It looks pretty cheap.
But, if we have to choose, I'd leave it in the worker thread. It is
unlikely to trigger on newly dispatched messages (that were *just* taken
off the wire), and the worker thread check is critical to avoid wasting
work on requeued/delayed messages that no longer have clients waiting on
them.
sage
