It’s misleading. One version is reserving the memory and will zero it upon use. The other version allocates the memory and zeros every byte of the memory up fro

It’s misleading. One version is reserving the memory and will zero it upon use. The other version allocates the memory and zeros every byte of the memory up front by actually writing zeroes to it. It’s basically competing abstractions. Letting the kernel reserve pages and only zeroing them when used will hide the cost and amortize it across access. It’s worth knowing about but it’s also an artificial problem revealed by benchmarks.