Mimalloc

mimalloc is a free and open-source compact general-purpose memory allocator developed by Microsoft with focus on performance characteristics. The library is about 11000 lines of code and works as a drop-in replacement for malloc of the C standard library and requires no additional code changes. mimalloc was initially developed for the run-time systems of the Lean and Koka languages. Notable design aspects include free list sharding, eager page reset, and first-class heaps. It can co-exist with other memory allocators linked to the same program.
mimalloc is available on Windows, Mac OS X, Linux and *BSD. The source code is licensed under MIT License and available on GitHub.