Red hat 8.0 memory management

[retoon]

Hey, I ran Red hat 8.0 for a little bit, and noticed that it had kind of strange memory management. This is where it is wierd. I have 1 gb of ram, which should be way more then enough, actually rediculously more then enough. I would run apps in RH8, and close them. Play a few games, then close them. Out of nowhere my system would just start lagging. I would go into system monitor, and it would tell me that 995 mb of my gig of ram were being used at the moment. It displayed no applications running at the time. I was really confused. I don't know if there is some kind of known bug, or something like that? Or if I just have no idea what I am doing seeing as I am a newbie. I switched over to mandrake 8.2 (Will be getting 9 soon), and the problem went away. Not that it is all that urgent, but if any one has any input as to why, or even how it happened, I would like to know.

[Dun'kalis]

Thats normal Linux behavior. Linux isn't actually using all that RAM, and it'll free it whenever a program needs it.

[retoon]

It doesn't free up the ram when I need it. When I go to play tux racer, it starts acting very slowly. It starts using the swap file. I actually moved back to Red Hat 8, because Mandrake 8.2 just didn't seem to want to work with me. When I get my hands on mandrake 9.0, Ill give it a try. But, the problem still exists. Dun'Kalis, if you have any more input, or if any one else out there might me able to share a tip or two as to how to prevent this from happening, I would be much more then ablidged!:)

[teeitup]

I wouldn't be so worried about your memory. 1GB will make most people on this forum drool.

I would watch your cpu usage and processes. When your system starts to lag check top for a clue as to what is eating up CPU cycles.

[bwkaz]

Also, the VSZ and RSS columns in the output of ps aux or similar will give a clue as to which processes are eating your memory. VSZ is virtual size, the total amount of virtual memory that's in use by that process. RSS is resident set size, the total amount of physical memory (I think) in use.

Also, in the output of free, there is a "+/- buffers/cache" line that will report the true amount of mem used and free. Well, I should say that it will correct for kernel caching of filesystem data, at least, which is the largest source of misconceptions about Linux memory.

If free reports a bunch of memory used, but nothing in ps' output has a large RSS (note: the X process generally has a large, like >200MB, VSZ on my box), then something in your kernel may be leaking memory. Do you have the nVidia drivers installed? I've seen a couple of reports of that happening with them, but I don't know a solution ATM...

[retoon]

I am actually using an ATI video card. Its just kind of wierd that its doing this. I threw a gig in there cause it was cheap at the time, and I figured I wouldn;t have to deal with memory shortage for a long while. When I was using Mandrake 8.2, the whole memory problem went away. I figured I would try stopping the memory usage by ending processes being performed by the users. I just am not sure which processes are vital. The only way to solve the problem is to reboot the entire system, and part of the reason I am using Linux is because I've been told you don't have to. Any way, any more info would be appreciated.

[bwkaz]

Can you put the output of ps aux after you see this problem into a file (ps aux >ps.txt) and post it as an attachment? Otherwise, you can just post the process names (the last column of ps aux's output) of the processes that are using a lot of memory.

[hlrguy]

Linux/Unix will keep the program(s) you were running in memory in case you want to start them again. Over time, the full 1 gig will be used. Here is a simply way to see this. Next start, do nothing except open openoffice. It will take ~8-15 seconds to open. Check your system monitor. Exit openoffice, see that no memory is freed up. Start OpenOffice again, it will load in ~1-3 seconds. If another programs starts, and one of the 'resident' programs is in the way, the loaded program will simply use what it needs, and the application that was overwritten will read from disk instead of memory on start. I will try to find the option to put into your system to force Linux/Unix to not do this.

hlrguy

P.S. i see a lot of posts that tuxracer runs slow. I am working on other games, but had the same problems in Redhat 7.0., Really slow. It has to be tuned up to work well.