Possible memory leak?

[Stefan Ehmann]

On Tuesday 20 March 2007 10:44:07 Oliver Fromme wrote:
> Stefan Ehmann wrote:
>  > Sometimes I'm noticing very high memory usage. Nearly my whole memory
>  > (1GB) is used although I'm running my usual set of processes - normally
>  > memory usage is much lower.
>
> That's normal.  FreeBSD uses nearly all free memory for
> buffer cache and other kinds of caches.
>
>  > I killed most processes but memory usage remains high.
>
> How do you measure "memory usage"?  The numbers from top(1)
> are mostly meaningless.  Personally I think top should be
> removed from FreeBSD, because it confuses many people (in
> fact I think _most_ people don't interpret the numbers
> correctly), but some people seem to be in love with it. :-)
Obviously I'm one of those people that got it wrong.

My mistake was to think that a memory page is moved to the inactive/cache list 
automatically if it's not used for a longer time. But if I got it correctly 
now, this only happens when there's some kind of memory shortage and the 
pageout daemon is not sleeping.

Now that I think I understand it better, those numbers also seem okay to 
me. :)

What got me suspicious at first was that the systems sometimes started to swap 
although there should have been more than enough memory to fit all processes 
in physical memory. But I see this is also in the FAQ.

Thanks for all your help and hints.

Stefan