[Mono-dev] Shutdown and Threads

Mark Probst mark.probst at gmail.com
Tue Dec 11 05:10:10 EST 2007

Hi Dick, Paolo and everybody else!

Regarding our shutdown issues (like bug #337383): I tried out a few
shutdown test cases with the Microsoft runtime and it doesn't seem
like they allow new threads to be started once shutdown is in
progress.  One can instantiate a Thread in a finalizer and even call
Start() without causing an exception, but the thread will not run.
Instead it will get finalized, too.  Timers don't run anymore, either.
 Implementing a finalizer-chain (instantiating one more object in the
finalizer whose finalization causes yet another object to be
instantiated, etc) is possible, but at some point (maybe due to a
timeout, maybe due to how the GC shutdown is implemented) no new
objects can be created and an OutOfMemoryException is thrown.

So, what I propose to implement in Mono is this: Once shutdown is in
progress inhibit starting of new threads, normal as well as threadpool
ones.  Just fail silently (or write a warning message).  Then make
sure all threads are properly suspended.  Then do finalization.

Is everybody ok with that?


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