releasing of RAM - gwenview, gimp

stegerpl

Hi,

Since I have 4 GB of installed RAM I never thought to run in a problem with RAM so I disabled swap. However two weeks ago I figured out some effects when dealing with large photos (panoramas with 7 images each 2-3 MB). So I activated swap with 5 GB and added a free memory indication to one of my superkaramba themes.

Now I can see that when I work with gwenview (an image-viewer of KDE) as well as GIMP the memory consumption reaches the physical limits and swap is activated (rarely). But when I close the images within the programs, the memory consumption does not reduce. Even when I close the programs the memory consumption goes down to only about 3 GB and does not go back to about 1,5 GB which seems to be the normal consumption in my system.

Any hints where I can tune the release of memory ?
Is there a kernel feature which has to be activated ?
Any further information where I should have a look ?

Please post also which information you will need to help me - I do not want to post huge lists of useless information.

Peter
_________________
[1]... AMD Phenon X4-9950 on asus M3N78-EM with 4 GB of RAM - gentoo 10.1 - kernel 2.6.32 - kde 4.3.4
[2]... AMD Athlon XP 2500+ mobile on ASUS A7N8X with 512 kB RAM and 2xTT S-2300 - vdr-1.6.0 based on gentoo-2008.0

Ant P. · Watchman Joined: 18 Apr 2009 Posts: 6920

What does `free -m` output?

stegerpl · Posted: Sun Oct 11, 2009 4:23 pm Post subject:

Hi,

I just edited some images (max. RAM consumption about 3,5 GB) and made some outputs: one before I opened gwenview and GIMP, one after I closed them again (the last one) and four during working:

DirtyHairy · Posted: Tue Oct 13, 2009 9:29 am Post subject:

Not sure what's supposed to be wrong with this output. The second number in the "+/- buffers/cache" line gives you the amount of memory which is available, including the memory the kernel currently uses as I/O cache. Between the last free and the first one, this only differs by some 40MB (which has been supposedly claimed by some other, unrelated process(es)), so this looks fine for me. It's OK if you see less memory available in the "Mem:" line; the kernel will release buffers as needed.

stegerpl · Posted: Tue Oct 13, 2009 6:13 pm Post subject:

Hi,

In this example the effect is not as dramatic as it shows up at other days.

However, The system was rebooted when I made the first snapshot => 844 MB used.
Then I started the applications and after I closed both of them again I took the last snapshot => 1540 MB used

The difference is 696 MB. I can not estimate where they have gone, because it should be (almost) the same situation as before I started the applications.

OK I agree that applications might "waste" some memory or the system will keep some data in caches, but almost 700 MB ?!
On other days this amount reached almost 1.5 GB.

On the other hand I can read that the cached memory increased by 642 MB - that's almost what I am missing.
Maybe I am misreading the information.

Peter
_________________
[1]... AMD Phenon X4-9950 on asus M3N78-EM with 4 GB of RAM - gentoo 10.1 - kernel 2.6.32 - kde 4.3.4
[2]... AMD Athlon XP 2500+ mobile on ASUS A7N8X with 512 kB RAM and 2xTT S-2300 - vdr-1.6.0 based on gentoo-2008.0

gerard27 · Posted: Tue Oct 13, 2009 6:32 pm Post subject:

Hi stegerpl,
Have you ever noticed the following:
The first time you start an application it takes a certain amount of time before it runs.
You close it and a little while later you start it again and then it starts almost immediately?
I'm no expert at this but I am sure that the application remains in RAM hence the quick restart.
When you don't restart it and the system needs RAM for something else the memory will be freed.
The fact that your swap is barely used proves this.
I have 4G RAM too and deleted swap because it was never used.
Gerard.
_________________
To install Gentoo I use sysrescuecd.Based on Gentoo,has firefox to browse Gentoo docs and mc to browse (and edit) files.
The same disk can be used for 32 and 64 bit installs.
You can follow the Handbook verbatim.
http://www.sysresccd.org/Download

DirtyHairy · Posted: Wed Oct 14, 2009 8:56 am Post subject:

drescherjm · Posted: Wed Oct 14, 2009 5:44 pm Post subject:

eccerr0r · Posted: Thu Oct 15, 2009 7:02 pm Post subject:

drescherjm · Posted: Thu Oct 15, 2009 7:06 pm Post subject:

This is a desktop ASUS AM2 M2N board that is over 3 years old. The chipset is nForce4 but since the AMD CPU has the memory controller inside I do not believe the fault is with the nforce. Generally now all of our new file servers are $700 dual or quad core desktops with 8 to 10 harddrives using linux software raid 5 or 6.

Actually my XP 64 desktop that I am typing on now has the same mobo and cpu and it says is using all 8GB. I am not sure of the reason why I do not get all the ram under x86_64.
_________________
John

My gentoo overlay
Instructons for overlay