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by zyedidia 474 days ago
It sounds like what you're describing is one-time allocation, and I think it's a good idea. There is some work on making practical allocators that work this way [1]. For long-running programs, the allocator will run out of virtual address space and then you need something to resolve that -- either you do some form of garbage collection or you compromise on safety and just start reusing memory. This also doesn't address spatial safety.

[1]: https://www.usenix.org/system/files/sec21summer_wickman.pdf
2 comments
naasking 473 days ago
> For long-running programs, the allocator will run out of virtual address space and then you need something to resolve that -- either you do some form of garbage collection or you compromise on safety and just start reusing memory

Or you destroy the current process after you marshall the data that should survive into a newly forked process. Side benefit: this means you get live upgrade support for free, because what is a live upgrade but migrating state to a new process with updated code?

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kstrauser 474 days ago
Oh, nifty! I guarantee you anyone else discussing this has put more than my 5 minutes' worth of thought into it.

Yeah, if you allow reuse then it wouldn't be a guarantee. I think it'd be closer to the effects of ASLR, where it's still possible to accidentally still break things, just vastly less likely.

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