bpo-29861: release references to multiprocessing Pool tasks (#743)
* bpo-29861: release references to multiprocessing Pool tasks
Release references to tasks, their arguments and their results as soon
as they are finished, instead of keeping them alive until another task
arrives.
* Comments in test
diff --git a/Lib/multiprocessing/pool.py b/Lib/multiprocessing/pool.py
index ffdf426..ae8cec4 100644
--- a/Lib/multiprocessing/pool.py
+++ b/Lib/multiprocessing/pool.py
@@ -128,6 +128,8 @@
util.debug("Possible encoding error while sending result: %s" % (
wrapped))
put((job, i, (False, wrapped)))
+
+ task = job = result = func = args = kwds = None
completed += 1
util.debug('worker exiting after %d tasks' % completed)
@@ -402,10 +404,11 @@
if set_length:
util.debug('doing set_length()')
set_length(i+1)
+ finally:
+ task = taskseq = job = None
else:
util.debug('task handler got sentinel')
-
try:
# tell result handler to finish when cache is empty
util.debug('task handler sending sentinel to result handler')
@@ -445,6 +448,7 @@
cache[job]._set(i, obj)
except KeyError:
pass
+ task = job = obj = None
while cache and thread._state != TERMINATE:
try:
@@ -461,6 +465,7 @@
cache[job]._set(i, obj)
except KeyError:
pass
+ task = job = obj = None
if hasattr(outqueue, '_reader'):
util.debug('ensuring that outqueue is not full')