[brabel]

> had difficulty being adopted more broadly

Most applications don’t need to bother the user with things like how much memory they think will be needed upfront. They just allocate how much and when necessary. Most applications today are probably servers that change all the time. You would not know upfront how much memory you’d need as that would keep changing on every release! Static allocation may work in a few domains but it certainly doesn’t work in most.

[AlotOfReading]

It's best to think of it as an entire spectrum from "statically allocate everything with compile time parameters" to "directly call the system allocator for every new bit of memory". It's just a helpful way to separate the concerns of memory allocation from memory usage.

What this article is talking about isn't all the way at the other end (compile time allocation), but has the additional freedom that you can decide allocation size based on runtime parameters. That frees the rest of the application from needing to worry about managing memory allocations.

We can imagine taking another step and only allocating at the start of a connection/request, so the rest of the server code doesn't need to deal with managing memory everywhere. This is more popularly known as region allocation. If you've ever worked with Apache or Nginx, this is what they do ("pools").

So on and so forth down into the leaf functions of your application. Your allocator is already doing this internally to help you out, but it doesn't have any knowledge of what your code looks like to optimize its patterns. Your application's performance (and maintainability) will usually benefit from doing it yourself, as much as you reasonably can.

[ulbu]

you don’t know up front how much memory you’ll need, but you know up front how much memory you have.

[chris-]

That's just saying "we push our memory problems up the stack so our clients / users need to deal with that". The reason this works is because human users in particular have become accustomed to software being buggy and failing often.

[brabel]

What ?? It’s exactly the opposite of that! Memory allocation on demand frees users from having to worry about configuring memory settings, which static allocation requires except if you overallocate, which is problematic if lots of applications start doing. I absolutely don’t like the argument that memory is nearly free! Most laptops still come with around 8GB of RAM which a browser by itself can consume already … there’s really not a lot left when you also got Docker, compilers, music app, email and so on running. I have 64GB and still have to close apps sometimes because software nowadays does stupid things like overallocating. Don’t do that.