[plorkyeran]

Folly does take advantage of jemalloc to expand allocations in-place when possible, but afaik it doesn't do the more extreme optimization mentioned in the article where pages are moved to a different virtual address without actually paging into memory.

Sized deallocation made it into C++14.

[bodyfour]

Since 2.1, jemalloc does support using mremap to do large realloc()'s, although it seems to be off by default. You need "./configure --enable-mremap" to get it.

That's good news about sized deallocation, I hadn't noticed that there is an updated "N3778" proposal which apparently was accepted. I still haven't seen the dlmalloc work to support that show up in the main svn branch.