Question

I noticed when I run Xcode especially start to run Interface builder.
Mac osx occupied memory increased quickly.
Not only xcode, there are some other apps also cause memory occupy too much after running a while.
Even the memory of my mac is 4GB, some time I have to use tool to free memory.
What is reason and how to avoid this case happen in my developing mac app?

Welcome any comment

Answer 1

I just experienced something similar(but probably not the same) in my Qt application.

I was reading and checksumming lots of files and the free memory kept dropping, though my appliations “real memory” stayed at a steady 50ish MB. However the amount of “Inactive memory” kept climbing.

What was happening was that every file i read was being added to the disk cache. The memory consumed by the disk cache is apperantly marked as “inactive”, which should be just as availible as “free” memory according to apple ( http://support.apple.com/kb/HT1342 ) but that didn’t stop OSX from starting to swap when “free” hit below 50ish MB.

in C:

  #include "fnctl.h"
  fcntl(f.handle(),F_GLOBAL_NOCACHE,1);

Seemd to fix that by bypassing disk caching for that file descriptor.

Freeing up inactive memory ( if that is indeed your problem ) can also be done from the commandline using the “purge” command.