Function jemalloc_memory_stats 

fn jemalloc_memory_stats() -> MemoryStats

Get memory statistics from Jemalloc

• stats.allocated: Total number of bytes allocated by the application.
• stats.active: Total number of bytes in active pages allocated by the application. This is a multiple of the page size, and greater than or equal to stats.allocated. This does not include stats.arenas.<i>.pdirty, stats.arenas.<i>.pmuzzy, nor pages entirely devoted to allocator metadata.
• stats.resident: Total number of bytes in physically resident data pages mapped by the allocator.
• stats.metadata: Total number of bytes dedicated to jemalloc metadata.

Reference: https://jemalloc.net/jemalloc.3.html