Home/ Questions/Q 6900167
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-27T07:30:43+00:00

I’ve heard rumors that calling malloc leads to so called dirty memory, which you

  • 0

I’ve heard rumors that calling malloc leads to so called “dirty memory”, which you can see in the VM Tracker instrument.

Now, rumors also say one must try to keep the amount of dirty memory as low as possible. But what they didn’t talk much about was how to undirty it again.

Sometimes there’s no other option than using malloc(). Heck, I love malloc(). For example when creating audio sources for OpenAL, one must malloc() a lot of data.

So: When my app calls malloc() and free() all over the place, I always believed that’s fine. Am I having a huge problem when doing that? Or will free() always “clean it up”? I’m a bit confused because some very big guys at a very big company warned that malloc() must be avoided as much as possible, because of this dirty memory problem.

Maybe someone can un-confuse me about that.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    If you malloc and free same size memory blocks multiple times, the memory will be reused instead of accumulating dirty VM pages. So it’s perfectly safe as long as you know the max of all possible fragment sizes ever allocated by your app at any one time, and that keeps your app under the OS kill limit.

    • 0