什么可以解释超过500万的系统。托管堆上的弱引用实例?

I have been running load tests against a production ASP.NET web application and am seeing a huge number of System.WeakReferences created on the heap. Within about 15 minutes under load managed heap memory has shot up to about 3GB and I have approximately 5,000,000 references to System.WeakReference. Performing a forced garbage collection of all generations does not release these references.I have been running load tests against a produc