[SLL] Memory Leak Evidence from free, prompted by apache application use, but not cleared by apache restart

[Xeno Campanoli]

Jesse Keating wrote:
> On Wed, 2008-05-14 at 14:37 -0700, Xeno Campanoli wrote:
>> I have an apache analysis application that is using lots of memory, but 
>> when I bring apache down, the memory usage registered in free does not 
>> go down by the amount it went up from the application.  Is there a 
>> kernel memory leak like this?  Seems pretty unlikely.  My uname -a is:

I'm going to use the sneezes I'm getting as an excuse:  It's not a 
memory leak after all.  All that memory is just left as cached, so I 
guess that means it's really still available, it's just registered as 
cached, rather than free.

My tool has just a massive use of memory, which I guess I expect due to 
the way I'm doing things.  As it's an internal tool, I focused 
completely on clarity and accuracy, and not at all on efficient use of 
memory, so it's just gobbling it up.

I realized I hadn't been paying attention to all the output from free 
when I completely stopped the apache2 daemon, and the memory level 
stayed virtually the same.  Then I looked at the thing more closely and 
found it was all accounted for by the caching column.

Any suggestions as to better memory analysis tools for things like this 
would be a happy addendum to this discussion from my point of view.

Thanks all.

Sincerely, Xeno
> 
> It would help if you posted some before and after output.  Are you sure
> you're not getting confused by the +/- buffers/cache output?  The memory
> usage may still be in cache but that doesn't mean it can't be re-used by
> something else that may need it.
> 
> Unused ram is wasted money, so caching is good.  It's when you start
> swapping that you need to be concerned.
>