tcmalloc central cache too large memory about tcmalloc

[vinllen]

I think the only reason is the memory fragmentation rate is too high, but it doesn't make sense in my scenrio.

[ckennelly]

gperftools is a separate repository. It is based on a many year old version of TCMalloc.

Memory being retained in the CentralFreeList likely indicates that spans are not being fully reassembled--some of the objects are still allocated (or in another cache), so the span accumulates free objects but is not fully returned to the PageHeap.