[haiku-development] Weird memory behaviour.

First, a bit of background: When checking our the sources inside haiku using R5's svn client, the amount of used memory starts to increase until, it reaches around 1.3 Gb at the end of the checkout process. This could even be considered ok if it was not for the fact that even after svn closes, the 1.3 Gb of memory is still in use by the kernel and this does not go down. As a reference, my machine has 3 Gb of memory usable by Haiku and around 1.5 Gb are in use by caches when svn finishes. Note that it is 1.5 Gb of caches plus 1.3 Gb of actual used memory that I see.
Anyway, I decided to track this bug down and did some very simple experiments to try to track down the memory behaviour and I saw something interesting:
1 - Right now, I am running haiku under VMWare. ActivityMonitor is open and it shows 95.9 Mb of used memory and 19.6 Mb of cached memory. 

2 - I compiled the following simple program under Haiku:

#include <unistd.h>

int main(void) {
  char* test - new char[1024 * 1024 * 500]
  sleep(5); // Give some time so AM can pick the change.

  // Intentionally leak allocated memory.
}
3 - When running it, Activity monitor does pick the memory change (memory usage goes up to 683.4 Mb) and, when the program exists, cleanup happens as expected (memory usage goes back to 95.9 Mb).
4 - What is weird is that, at the same time, Cached memory goes *DOWN* to -567.6 Mb (yep, a negative number) which led me to believe that somewhere we are unconditionally decreasing the amount of cached memory even when we do not need to do that to allocate the required memory.
5 - This could also see the reason why I see 1,3 Gb in use by the kernel after a svn checkout as it could actually be cache memory that was incorrectly tracked as used memory due to something related to above.
I will continue investigating it but as I am at work now I won't be able to dedicate too much time to it. if you have any idea about what could be happening, please say so. :) 

-Bruno

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