Comment 7 for bug 903199

A few hours' test shows that this patch is effective in preventing the accumulation of _DummyThread objects.

The memory footprint does still increase over time. At the moment, I think this is due to SQLAlchemy keeping hold of InstanceState objects. Some of the SQLA caching has an upper limit, but we will need to monitor this.

To go back to eventlet though. Vish, what side-effects can we expect from this patch? Does it not have the potential to change the synchronisation between eventlets; during locking, logging, or waiting on subprocesses?