[Python-ideas] Ideas towards GIL removal (original) (raw)

Josiah Carlson jcarlson at uci.edu
Sun Apr 15 20:16:53 CEST 2007

Greg Ewing <greg.ewing at canterbury.ac.nz> wrote:

Josiah Carlson wrote:

> Certainly, but thread B isn't the owning thread, thread A was the owning > thread, and by virtue of decrefing its thread count to zero, acquiring > the GIL, and checking the global refcount to make sure that either > someone else is responsible for its deallocation (global refcount > 0), > or that thread A is responsible for its deallocation (global refcount == > 0). Thread B holding the GIL doesn't help, because the local refcount is not covered by the GIL. Thread A must be able to assume it has total ownership of the local refcount, otherwise there's no benefit in the scheme.

I seem to not be explaining myself well enough. What you describe is precisely what I described earlier. I don't believe we have a disagreement about the execution semantics of threads on an object with a local thread count.

I was only mentioning A acquiring the GIL if/when it becomes finished with the object, to determine if the object could be sent to the standard Python deallocation rutines, and/or if thread A should send it (as opposed to thread B in the case if thread B was passed the object and was using it beyond the time that A did).

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