It's in zig but I just call mmap twice at startup to get one slab of memory for ... | Hacker News

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		anonymoushn on June 23, 2022 \| parent \| context \| favorite \| on: How safe is Zig? It's in zig but I just call mmap twice at startup to get one slab of memory for the whole file plus all the space I'll need. I am not sure whether Zig's GeneralPurposeAllocator or PageAllocator currently use mremap or not, but I do know that when realloc is not implemented by a particular allocator, the Allocator interface provides it as alloc + memcpy + free. So I think I would not OOM. In safe builds when using GeneralPurposeAllocator, it might be possible to exhaust the address space by repeatedly allocating and freeing memory, but I wouldn't expect to run into this on accident.

dundarious on June 23, 2022 | [–]

They don't (at least the GPA's defaulting backing allocator is the page_allocator, which doesn't). https://github.com/ziglang/zig/blob/master/lib/std/heap.zig

woodruffw on June 23, 2022 | [–]

That's interesting, thanks for the explanation!

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