So it's a hash table that's about twice the size of physical memory. The entries in the hashtable are usually pointers to memory that you need to deallocate (c

So it's a hash table that's about twice the size of physical memory. The entries in the hashtable are usually pointers to memory that you need to deallocate (char* filenames in this case, maybe some other stuff too) so if you're a good citizen you iterate through them all and deallocate (mark is as free) them as you go. It would seem there were some pathological swap issues doing that. It would be interesting to see if a tree behaved better in this type of situation. The allocator has tables of its own in memory too, if you have to swap those out to find the memory that your then going to deallocate then swap out all the user data structures to swap in the allocator's structures to do the deallocation or something whacky like that, it kind of makes sense. His patch just skips that step and ends the program.