3 ms·

We would stay ahead of the curve on maintenance, if the kernel and other software was easier to live-patch and it was the default & very stable in pretty much a

We would stay ahead of the curve on maintenance, if the kernel and other software was easier to live-patch and it was the default & very stable in pretty much all relevant distributions. No more clusters just for the sake of being able to update during business hours. Also, as a Clojure dev, you cannot recompile the running kernel while using it at the same time using something akin to REPL driven development. That would be the other side of the live-patch productivity boost in so many areas. If I am not mistaken, the CPU and other devices don't care, if everything is compiled ahead of time and a few functions tacked on later, as they are changed by e.g. patches, or if the kernel is completely recompiled. Obviously, I am simplifying a lot but it is a very serious question. We really should strive to build maintainable systems that don't have to reboot just to apply updates.

pabs3 5y ago
The Linux kernel already supports live-patching, but as I understand it, the patches themselves are hard to produce or can't be produced automatically, so to be able to produce them you need a team that understands the process, which limits the live patching to commercial distros that can afford a team for this.
- kaliszad 5y ago
  I know, and that is exactly my point. It isn't like "send to REPL" in pretty much any half-decent LISP. And it hurts development comfort, speed and maintenance is way more burdensome than what it could be. Here, you would need to involve a compiler of course and do more due diligence and then run ftrace or something to exchange the code. Also, you would probably in some cases need to make sure, the ordering of code is right as to not hurt performance. (See Emery Berger's talk https://www.youtube.com/watch?v=7g1Acy5eGbE https://www.youtube.com/watch?v=7g1Acy5eGbE which probably applies here as well.) Of course, with great power comes great responsibility. You could add some optional checking facility, that would be able to roll back the changes to code if some conditions were met.
  - Dylan16807 5y ago
    I think worrying about existing data structures in memory is a lot bigger part of the problem than putting new code into place.
    - kaliszad 5y ago
      Some of that problem space could probably be reduced by immutable/ CoW data structures modeled after Clojure/ Rich Hickey/ Phil Bagwell https://www.youtube.com/watch?v=K2NYwP90bNs https://www.youtube.com/watch?v=K2NYwP90bNs The rest could probably be solved by a very short "stop the world and switch a few pointers" routine.

pabs3 5y ago

The Linux kernel already supports live-patching, but as I understand it, the patches themselves are hard to produce or can't be produced automatically, so to be able to produce them you need a team that understands the process, which limits the live patching to commercial distros that can afford a team for this.

kaliszad 5y ago
I know, and that is exactly my point. It isn't like "send to REPL" in pretty much any half-decent LISP. And it hurts development comfort, speed and maintenance is way more burdensome than what it could be. Here, you would need to involve a compiler of course and do more due diligence and then run ftrace or something to exchange the code. Also, you would probably in some cases need to make sure, the ordering of code is right as to not hurt performance. (See Emery Berger's talk https://www.youtube.com/watch?v=7g1Acy5eGbE https://www.youtube.com/watch?v=7g1Acy5eGbE which probably applies here as well.) Of course, with great power comes great responsibility. You could add some optional checking facility, that would be able to roll back the changes to code if some conditions were met.
- Dylan16807 5y ago
  I think worrying about existing data structures in memory is a lot bigger part of the problem than putting new code into place.
  - kaliszad 5y ago
    Some of that problem space could probably be reduced by immutable/ CoW data structures modeled after Clojure/ Rich Hickey/ Phil Bagwell https://www.youtube.com/watch?v=K2NYwP90bNs https://www.youtube.com/watch?v=K2NYwP90bNs The rest could probably be solved by a very short "stop the world and switch a few pointers" routine.