Richard Oudkerk added the comment: I think Sebastian's algorithm does not correctly deal with the non-blocking case. Consider the following situation:
* Thread-1 successfully acquires exclusive lock. Now num_got_lock == 1. * Thread-2 blocks waiting for shared lock. Will block until (num_got_lock == 1 and excl_count == 0). Now num_got_lock == 1. * Thread-3 does non-blocking acquire of shared lock but fails. Now num_got_lock == 2. Now, since num_got_lock == 2, the predicate that Thread-2 is waiting for will not happen until num_got_lock overflows. This is probably fixable if we just prevent a failed non-blocking acquire from modifying num_acq_lock and num_got_lock. (But I don't see how to extend the algorithm to allow timeouts.) ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue8800> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
