When considering pages to queue for eviction, we treat pages over the memory_page_max size limit specially and queue them for "urgent" eviction. However, such pages may have grown large because they contain a lot of history that cannot be evicted, so there is no point queuing them for urgent eviction unless they are dirty. This is the same approach taken when a page is released.
- related to
SERVER-37849 Poor replication performance and cache-full hang on secondary due to pinned content