7 ms·

Memory is meant to be reused, "64 bit counter will be enough for everybody" is not how systems programming works.

• nyanpasu64 3y ago
  > "64 bit counter will be enough for everybody" is not how systems programming works. Except when it is: https://threatpost.com/another-linux-kernel-bug-surfaces-allowing-root-access/137800/ https://threatpost.com/another-linux-kernel-bug-surfaces-all..., fix at https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/mm/vmacache.c?id=7a9cdebdcc17e426fb5287e4a82db1dfe86339b2 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin...
  • hinkley 3y ago
    VMAs sound expensive. Of course a 64 bit counter is going to work for moderately expensive things. If you have a multithreaded app doing a lot of communication, that's going to be a lot of cheap allocations happening very fast. Reducing GC and allocation overhead results in more allocations being done, and pushback against ever-expanding allocation behavior is more of a challenge. Instead of ten other things being a higher priority than judicious data architecture, it's dozens or more.
• slashdev 3y ago
  Except when it is. You'd be surprised what systems programming looks like. Reference counts are not re-used when memory is re-used. And again, even if for some reason you had a global 64bit counter that you incremented on every allocation and never decremented, and you could somehow handle a billion allocations per second, you'd have 585 years before that counter overflowed back to 0. No computer or program can run for that long.