factor

Author	SHA1	Message	Date
Slava Pestov	c36d73e242	Change do-callback to register the current thread with the callback, instead of busy waiting for the current callback to become the right one before returning. Fixes 100% CPU usage issue with system-alert. Thanks to Blei and ex-rzr for doing preliminary analysis of the issue	2011-04-12 21:48:54 -04:00