[mono442]

The problem with disabling the memory overcommit is that then the RAM is wasted. That can be worked around with setting up swap but then the disk space is wasted.

[man8alexd]

People like to reinvent things that they are not aware of. Original BSDs used to use strict swap reservation - every anonymous memory page had to have an associated swap page. You had to have the swap 2x of RAM to allow large processes to fork - otherwise you would get an "out of swap" error. FreeBSD implemented overcommit around 2000, I think version 4.x or 5.x.

[frollogaston]

Why are programs even allocating memory that they don't use?

[man8alexd]

Because no one can predict the future, and they don't know how many resources they will need.

[frollogaston]

I mean they can just malloc when they need more, what am I missing? Unless this is about JVMs which might preallocate a ton for their heaps and not use it

[swappie]

Apps could, yes.

But it’s about 1000x slower to call the OS to allocate a new page, than to just use a pointer to preallocated space.