Controlling Finalization Queue

The runtime provides two methods to control objects’ eligibility for finalization, GC.SuppressFinalize and GC.ReRegisterForFinalize. GC.SuppressFinalize removes an object from the list of objects that will be finalized when they are no longer reachable, and GC.ReRegisterForFinalize takes an object that was previously suppressed, and adds it back to the list.
GC.SuppressFinalize is used to prevent unnecessary and costly finalization after the object has been cleaned up through other means, for example through IDisposable interface. GC.ReRegisterForFinalize is used to assure resource cleanup after an already cleaned up object reacquires resources that will need to be cleaned up.
In the .NET Framework Beta 2 release, there is a very expensive security check in GC.SuppressFinalize. This check has been removed in the final release, and should not be a source of performance problems.