One thing that has been known for a while is that there are allocation patterns where LibC malloc doesn't give back a sufficient amount of pages even when the p

One thing that has been known for a while is that there are allocation patterns where LibC malloc doesn't give back a sufficient amount of pages even when the pages are clean. See for example https://www.joyfulbikeshedding.com/blog/2019-03-14-what-causes-ruby-memory-bloat.html#a-magic-trick-trimming https://www.joyfulbikeshedding.com/blog/2019-03-14-what-caus... . In the end I think the consensus was that jemalloc was just better than invocing malloc_trim, but invoking malloc_trim now and then can certainly be a lot better than using neither malloc_trim or jemalloc.