One place I had issues was rapidly allocating space I needed temporarily but then discarding it.

The space I needed was too large to be added to the heap, so I used mmap. Because of the nature of the processing (mmap, process, yeet mmap) I put the system under a lot of pressure. Maintaining the set of mapped blocks and reusing them around fixed the issue.

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vlovich123 3 days ago | parent [-]

Freeing memory to the OS or doing things like munmap involves a TLB shootdown which by definition is a performance bottleneck. Probably what you ended up experiencing.

	▲	OptionOfT 2 days ago \| parent [-]
		Thanks for that. That was an interesting read! I ended up in this situation like I end up in most, by just learning as I go. With this I learned that the libc allocator has a max amount that it'll add to the heap, and how mmap works, and that doing frequent munmap is slow. Now I learned why it is slow!