diff options
Diffstat (limited to 'Lib/threading.py')
| -rw-r--r-- | Lib/threading.py | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/Lib/threading.py b/Lib/threading.py index fb70abd..6c3d49c 100644 --- a/Lib/threading.py +++ b/Lib/threading.py @@ -780,12 +780,27 @@ _active_limbo_lock = _allocate_lock() _active = {} # maps thread id to Thread object _limbo = {} _dangling = WeakSet() + # Set of Thread._tstate_lock locks of non-daemon threads used by _shutdown() # to wait until all Python thread states get deleted: # see Thread._set_tstate_lock(). _shutdown_locks_lock = _allocate_lock() _shutdown_locks = set() +def _maintain_shutdown_locks(): + """ + Drop any shutdown locks that don't correspond to running threads anymore. + + Calling this from time to time avoids an ever-growing _shutdown_locks + set when Thread objects are not joined explicitly. See bpo-37788. + + This must be called with _shutdown_locks_lock acquired. + """ + # If a lock was released, the corresponding thread has exited + to_remove = [lock for lock in _shutdown_locks if not lock.locked()] + _shutdown_locks.difference_update(to_remove) + + # Main class for threads class Thread: @@ -968,6 +983,7 @@ class Thread: if not self.daemon: with _shutdown_locks_lock: + _maintain_shutdown_locks() _shutdown_locks.add(self._tstate_lock) def _bootstrap_inner(self): @@ -1023,7 +1039,8 @@ class Thread: self._tstate_lock = None if not self.daemon: with _shutdown_locks_lock: - _shutdown_locks.discard(lock) + # Remove our lock and other released locks from _shutdown_locks + _maintain_shutdown_locks() def _delete(self): "Remove current thread from the dict of currently running threads." |