Brian Pane wrote: > Weren't the thread management problems with the threaded MPM > related specifically to shutdown? If it's just shutdown that's > a problem, it may be possible to solve it.
The basic problem was the global accept mutex. Once it was time for a process to die, we didn't have a reliable way to wake up all the threads in that process who were waiting on the mutex. We would see this with graceful restarts and after ap_process_idle_server_maintenance decided it had too many workers. If you looked at mod_status, you would see processes with a few idle threads and often a "G" hanging around indefinately. But other than that, graceful restarts worked fine. This problem didn't exist when we used separate intra-process and cross-process accept mutexes, because once it's time to die, nobody acquires the intra-process mutex. But that requires an extra syscall on every request. With your design, we shouldn't have the problem where some threads in a process are blocked in mutex land unaware that it's time to die, because only one thread at a time is an accept thread. Non-graceful restarts in threaded had the same problem worker has today: no way to blow away threads which are serving long-running requests. Greg
