Re: thread resource leaks if thread terminates with uncaught exception

Shiro Kawai <[email protected]> writes:

> I pushed a fix of pmap to ensure all worker threads are joined.  Seems to
> be working with simple manual tests.  It's a bit difficult to write an
> automated test for it, though.

looking at:

(define-method run-map ((mapper <fully-concurrent-mapper>) proc coll)
  (let ([unique (list #f)]
        [ts (map (^e (make-thread (^[] (proc e)))) coll)]
        [timeout (absolute-time (~ mapper'timeout))]
        [timeout-val (~ mapper'timeout-val)])
    (%start-threads ts)
    (%with-wrapped-join
     (let1 join! (%make-joiner #f)
       (if timeout
         ($ map (^r (if (and (pair? r) (eq? (car r) unique))
                      (begin (thread-terminate! (cdr r)) timeout-val)
                      r))
            $ map (^t (join! t timeout (cons unique t))) ts)
         (map join! ts))))))
)

A difference to my "solution" is that you don't terminate all threads in
case of an early error immediately, but maybe this is a good thing.

I still wonder about the timeout case. But it looks like one doesn't
have to join after a successful thread-terminate!. Then only a failing
thread-terminate! case might cause a problem/"died a lonely death"?

Jens