System Memory

usage grows

[David]

I am not sure where to look for this. When I boot the system it shows 26% memory used. After working a bit. and then closing all applications when I check the memory usage it jumps to around 98%. I have 512 megs of ram on the machine. The biggest part of the memory iused s allocated to "user" currently its at 379 megs.
This just doesn't look right to me.
Any Thoughts?

[littleman]

Open a terminal and run 'top', then hit shift+m. That will show what activities are using the most memory -- they are listed in descending order. It could be something you are shutting down gets caught in a loop.

BTW, be sure to quit top before closing your terminal.

[David]

Thanks,
I started "top" and then started loading programs. If I load

kmail it shows one entry 13M 2.6%
Mozilla shows 4 entries 22m 4.5% each
Opera shows 2 entries 9.9M 1.9% each
Quanta shows 1 entry 14M 2.8%

Then there are several KDEINIT that add up to quite a bit. I am guesing that these are reserved for KDE, because when I load Konqueror one of the KDEINIT entries jumps up in size but I can't see a Konqueror entry.

As I close programs it frees some memory but the buffer looks like it keeps growing. Right now I have a buffer of 273 megs.

Is it normal to have several entries for one application (maybe its showing the different memory blocks).

What do you think?

[littleman]

Yeah, a lot of applications will make several entries in top which will make them look like they are actually using more resources than they are.

You could try running free and check out the results. Here is mine:
$ free
total used free shared buffers cached
Mem: 126644 119736 6908 700 8804 59304
-/+ buffers/cache: 51628 75016
Swap: 248968 984 247984

The way I understand it is that Linux will hold data in memory as buffer and cache until another application comes along to occupy that space. Once that happens it will get flushed as needed. So in that sense buffer is like free memory with place holdings.

[sugarkane]

> Linux will hold data in memory as buffer

Yep, it's not uncommon for memory usage to be in the high 90s, and it's nothing to worry about, just a sign that the kernel memory management is doing its job. If, however, you start seeing a high percentage of swap being used as well then it could be a sign that something's awry - probably a memory leak in a buggy application.

> KDEINIT entries jumps up in size but I can't see a Konqueror entry

KDE uses KDEINIT as a 'wrapper' to launch KDE programs, and hopefully trap any crashes before they have a chance to bring the desktop down. I'm not sure whether I like this idea - it makes it difficult to find the PIDs of programs, but does seem to improve stability.

[scotty]

If, however, you start seeing a high percentage of swap being used as well then it could be a sign that something's awry - probably a memory leak in a buggy application.

Not necessary. Basically, Free Memory are Waste Memory - they are just sitting there storing nothing. A good operating system should try to utilise all the free memory into buffers and caches. The same applies to the swap memory. Memory are better utilised when the OS pages the rarely-used applications into swap, and then uses re-gained space for cache. On a typical running system, it is quite common to have processes running that only get used once a day (or even once a week!). When they are not used, the memory they occupy are just wasted...

KDE uses KDEINIT as a 'wrapper' to launch KDE programs, and hopefully trap any crashes before they have a chance to bring the desktop down.

KDE also uses KDEINIT to initialise the libraries and the C++ virtual tables, I think, and that greatly improves the application launch speed. It does not use the fork + execve to start up new apps, but does a dlopen instead.

You can read more about it here:
[suse.de ]