Boosted swappiness with Fedora
Quite some time ago we had a topic about swappiness here on Nuxified. There I posted that, more or less no matter what I do, my 1GB swap-partition is hardly ever used.
At that time I was running Linux from Scratch, with the default swappiness of 60.
Now that I use Fedora 7 I found a big difference. Although the amount of memory I have only has decreased by 128MB (because on my new board I have an onboard-VGA with shared memory) I commonly find around 400MB of swap (now 4GB in size) used.
Right now about 500MB of swap are in use, while compiling EasyLFS in KVM. That this increases swapping should be understandable, but shouldn't it also have done that before I switched to Fedora?
So what does Fedora do different than LFS? The swappiness is also set to 60, so there's no difference. Is there maybe some kernel-patch that makes the system swap more?
It doesn't seem to need a daemon to swap (why should it anyway, it's done by the kernel), so it can't be that I just missed to run it on LFS so that it didn't swap (and it did swap sometimes, just not really much).
Okay, Fedora is running a few programs more than I used to run with LFS, but a few daemons more shouldn't account for 400MB of swapped RAM.
And I don't really think it's related to being a 64-Bit-system now.
Inside the mentioned KVM I also have swap-space, 1GB. 384MB of memory are assigned to the virtual machine. You should think you'd see a certain amount of swapping there since compiling can take quite an amount of memory, but there's only 124K of swap being used!
And I also don't think that it's that the Fedora-kernel comes with a lot of modules. Really, if all those modules need 400MB of memory we should really reconsider if Linux is really such a good OS. And if they're not used (which would be a necessity for them to be swapped out) they should be unloaded. But anyway, I don't think it's the modules. Most of the modules loaded now in Fedora I had statically compiled into my kernel in LFS, and after bootup it didn't eat up 400MB of my memory.
I don't really understand it. No matter what's the reason for it, I don't think it really helps much. Of course having swap-space is good, and that swap-space is used when something isn't used and something active needs the memory is right, good and important. But why does Fedora need to swap more than LFS? Is it because LFS is built for my system? That all the binaries and stuff work so much more efficient that swapping becomes nearly unnecessary?
I'd actually love to believe that, but it's quite hard.
Well, whatever the reason may be, I'm quite happy with Fedora. It runs nicely and is a lot easier to handle than LFS. I think over the past years, having started with Linux in 1999, I did my share of compiling to know now how it works, and now I can lean back and relax with a distro that updates with a click of the mouse and use my "compiling-skills" for something useful: EasyLFS.