From: Parthasarathy Bhuvaragan <parthasarathy.bhuvara...@ericsson.com> Date: Tue, 12 Apr 2016 13:05:21 +0200
> Until now, the requests sent to topology server are queued > to a workqueue by the generic server framework. > These messages are processed by worker threads and trigger the > registered callbacks. > To reduce latency on uniprocessor systems, explicit rescheduling > is performed using cond_resched() after MAX_RECV_MSG_COUNT(25) > messages. > > This implementation on SMP systems leads to an subscriber refcnt > error as described below: > When a worker thread yields by calling cond_resched() in a SMP > system, a new worker is created on another CPU to process the > pending workitem. Sometimes the sleeping thread wakes up before > the new thread finishes execution. > This breaks the assumption on ordering and being single threaded. > The fault is more frequent when MAX_RECV_MSG_COUNT is lowered. > > If the first thread was processing subscription create and the > second thread processing close(), the close request will free > the subscriber and the create request oops as follows: ... > In this commit, we > - rename tipc_conn_shutdown() to tipc_conn_release(). > - move connection release callback execution from tipc_close_conn() > to a new function tipc_sock_release(), which is executed before > we free the connection. > Thus we release the subscriber during connection release procedure > rather than connection shutdown procedure. > > Signed-off-by: Parthasarathy Bhuvaragan > <parthasarathy.bhuvara...@ericsson.com> > Acked-by: Ying Xue <ying....@windriver.com> Applied, thanks.
