Message 66363 - Python tracker

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In-reply-to
Author	Rhamphoryncus
Recipients	Rhamphoryncus, amaury.forgeotdarc, gregory.p.smith, gvanrossum, kbk, larsimmisch
Date	2008年05月07日.18:11:43
SpamBayes Score	0.009410914
Marked as misclassified	No
Message-id	<1210183915.75.0.0624230391664.issue1856@psf.upfronthosting.co.za>

Content
Cleaned up version of Amaury's patch. I stop releasing the GIL after sys.exitfunc is called, which protects threads from the ensuing teardown. I also grab the import lock (and never release it). This should prevent the nasty issue with daemon threads doing imports mentioned in issue 1720705, so that part of the documentation change can be removed. I didn't do any significant testing though. Importing raises a potential issue with this approach. The standard meme of "release GIL; grab lock; acquire GIL" becomes invalid. A child may grab the lock, then block on the GIL, while the main thread (which never releases the GIL) will block on acquiring the lock. I worked around it with the import lock due to it's recursive behaviour, but if it exists anywhere else in CPython it may cause a problem if used during shutdown.

Content

Cleaned up version of Amaury's patch. I stop releasing the GIL after
sys.exitfunc is called, which protects threads from the ensuing teardown.
I also grab the import lock (and never release it). This should prevent
the nasty issue with daemon threads doing imports mentioned in issue
1720705, so that part of the documentation change can be removed. I
didn't do any significant testing though.
Importing raises a potential issue with this approach. The standard
meme of "release GIL; grab lock; acquire GIL" becomes invalid. A child
may grab the lock, then block on the GIL, while the main thread (which
never releases the GIL) will block on acquiring the lock. I worked
around it with the import lock due to it's recursive behaviour, but if
it exists anywhere else in CPython it may cause a problem if used during
shutdown.

History
Date	User	Action	Args
2008年05月07日 18:11:56	Rhamphoryncus	set	spambayes_score: 0.00941091 -> 0.009410914 recipients: + Rhamphoryncus, gvanrossum, gregory.p.smith, kbk, amaury.forgeotdarc, larsimmisch
2008年05月07日 18:11:55	Rhamphoryncus	set	spambayes_score: 0.00941091 -> 0.00941091 messageid: <1210183915.75.0.0624230391664.issue1856@psf.upfronthosting.co.za>
2008年05月07日 18:11:54	Rhamphoryncus	link	issue1856 messages
2008年05月07日 18:11:52	Rhamphoryncus	create

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