3 ms·

Worse, it breaks all pointers since you can't guarantee `mmap` can give you the same address.

• astrange 3y ago
  I think you could fixup the pointers if you tried. It's more or less the same problem as compacting GC.
  • o11c 3y ago
    Certainly there are solutions, but they aren't transparent, and at some point you have to ask "would serialization be easier?"
    • GTP 3y ago
      This is exactly what I thought: why not just save state to a file?
• junon 3y ago
  You can detect when it doesn't, though, I think. If memory serves you can request a specific memory address to mount it at and it'll do it if it's not already mapped. It should (in theory?) return an error in such a case, no?
  • deciduously 3y ago
    I believe on conflict it will just fall back to placing it where it can by default. It will return the address it actually used, so you can catch the mismatch.
• kouteiheika 3y ago
  You absolutely can, with `MAP_FIXED`. But it's not trivial to do because you'd have to handle the case where the rtld and/or the kernel has already put something in memory where you want to put down your map. So it'd be tricky to implement, but definitely possible.
  • mike_hearn 3y ago
    That can be fixed with a linker script, to reserve the range using ELF headers. But then you're going to hit other problems. This isn't a new idea. Presumably one of the reasons you're restarting your server is to upgrade it ...