Does gc.collect really release memory?

Question

I am trying to release memory using gc.collect(). But I do not really understand how it works. For example:

Before I run del and gc, the used memory is 58g. After running them, the used memory is still 58. It looks that no memory has been released. I sense gc is different than shutting down python and starting again, which actually release memory.

So I am wondering how to actually release the memory so that I can load other data?

Answer 1

Depending on your OS, it may not take back the released memory.

You can try out malloc_trim on Linux:

import ctypes

heavy_obj = create_heavy_obj()

# do some jobs

del heavy_obj
ctypes.CDLL("libc.so.6").malloc_trim(0)