Re: Memory usage on debian
Hans Wilmer wrote:
> On Sat, Jan 25, 2003 at 05:18:46PM -0500, Jason McCarty wrote:
>
> > > Well, it does :) What is the difference between 'cached' and
> > > 'buffers'? I wanted to know that since long, but never found out.
> >
> > Well, after digging through the kernel sources (such fun!), I think I
> > figured that out. "cached" is files that have been read from disk, but
> > aren't currently opened by any processes. "buffers" is the same, except
> > it counts opened files instead.
>
> Thanks for the info! Do files contributing to buffers contribute to
> cache at the same time?
The way free accounts it, there's no overlap, although the kernel
internally treats buffers as a subset of cache.
> > > What wonders me it the memory usage of Xfree86. It seems that with
> > > 492 root 7 -10 560M 15M 836 S < 0.0 3.1 219:38 XFree86
> >
> > Hmm, I would guess that the actual memory X is using is SIZE-512, so the
> > actual usage would be 48M.
>
> This would make a negative number of memory usage shortly after
> starting the X server :)
Doh! Wouldn't that be cool though :)
> > I have a 64MB video card, and X maps it as 4 times the actual size,
> > so that my SIZE is 270M, but X really only uses 14M.
>
> This would explain a lot! My card has afair 128 MB, accounted as 512
> MB plus 15 MB adds up to 527 --- plus some other memory actually used,
> but swapped out, plus maybe a little memory due to leaks.
>
> > That doesn't mean X doesn't leak, of course ;-) The problem might
> > just be that resource leaks in X programs cause memory leaks in the
> > X server.
>
> Hm, they shouldn't do that ...
Well, most of an X program's pixmaps and other GUI info is stored on the
X server. So if a program doesn't tell X when to discard them, X thinks
they're still in use, and doesn't free them.
So leaky X programs make your X server leak. It's not really X's fault,
since it can't do much about it. It might be able to clean up some when
programs exit, I'm not sure.
Jason
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