QHash : Virtual memory not released

[jbenoit]

I understand what you are saying, theorically...

Pratically, I am not sure where to begin.

My problem look like a fragmentation problem.

So, how can I defragment my memory in my application ? Pratically speeking...

To be more precise :

All in c++, using QT, on Windows OS

1) In c++, how can I disabled swap during run-time ?

2) In c++, how can I allocate more than all the free memory on your system using another process during run-time?

[squidge]

Both 1 and 2 are a bad idea for a typical application, so don't do either.

[jbenoit]

Ok. So, what can I do ?

There is what I want *need* to do in my app :

1) Allocate a large block of continous memory (cvCreateMat, from openCV)
2) I need to allocate many small block (QHash, for example, and others things) that mess up my fragmentation.
3) Deallocated the memory from 1)
4) Allocate large block of memory for PCA analysis.
5) Deallocated memory from 2) and 4)


And I need to repeat step 1 to 5 a couple of times.

The problem is that, when I try to redo step 1 for the second time, my memory is fragmented and I get a "inssuficient memory".

If I don't do step 3 (in order to reuse the matrice for the next iteration), I got an error on step 4 : "insufficient memor".


Any clues on what should I do ?

[squidge]

Which is the larger amount of memory required - cvCreateMat or the PCA analysis? Allocate it once and use it for both? Why deallocate when your going to need it again shortly anyway? Even if it is for another task.