This is factually false, and I'm wondering why you'd say that. Some of the more common malloc implementations out there are dlmalloc, jemalloc, and tcmalloc. H

This is factually false, and I'm wondering why you'd say that. Some of the more common malloc implementations out there are dlmalloc, jemalloc, and tcmalloc. Here is where they call munmap. https://github.com/ennorehling/dlmalloc/blob/71296436f979a350870e10b869ccfd28bfcc17e4/malloc.c#L3859 https://github.com/ennorehling/dlmalloc/blob/71296436f979a35... https://github.com/jemalloc/jemalloc/blob/c0c9783ec9289e6d1de749ff20081af65bdd78b8/src/pages.c#L233 https://github.com/jemalloc/jemalloc/blob/c0c9783ec9289e6d1d... Note that not all allocators work this way, you can see that tcmalloc will instead MADV_DONTNEED. (You can find munmap in tcmalloc, but it's not being used to free memory.) https://github.com/google/tcmalloc/blob/48808681a9f38e974b49619a126f6f949ff59520/tcmalloc/system-alloc.cc#L411 https://github.com/google/tcmalloc/blob/48808681a9f38e974b49...