PSA to #rustlang and #linux developers: there is a long-standing bug in the system allocator (glibc malloc) which causes it to hoard large sbrk buffers in arenas. By default, it uses heuristics to dynamically increase the mmap threshold—the point where it switches from using sbrk to mmap. In some scenarios, these larger buffers are never trimmed, causing a memory "leak". Some #libcosmic apps were affected, causing as much as 10-30x memory usage. To fix, see the PR below: