Thanks Jamie. Shane.
On Thu, 27 Apr 2006 13:52:35 -0600 (MDT), Jamie Furtner wrote > What "very low numbers" are you looking at? Are you looking at the overall > system memory in the header of top's output? > > If so, then it's normal behaviour from modern operating systems. The > short answer is "what good is all this memory if it's not used?" > It's easily available to processes if needed. > > When you look at the output from top or free, it's giving you most > of the information to figure out what's used and what's "free". What > you need to do is look at the buffers and cached lines. Those > indicate how much memory processes are using to cache (i.e. file > buffers, input queues, etc) and disk I/O, respectively. These are > Good Things, as accessing memory is much > (by an order of magnitude or so) faster then accessing disk. A lot > of the memory that is consumed by buffers and caches is easy to free, > the only cost being that the system will slow down as it has to go > to the hard drive to retrieve data more frequently. > > If you're ever curious to know how much memory is really available, try > the command 'free -mt'. It reports the current snapshot of overall memory > utilization. On my system, it reports this: > [EMAIL PROTECTED] /home/jfurtner $ free -mt > total used free shared buffers cached > Mem: 2027 1976 51 0 178 > 781 -/+ buffers/cache: 1016 1010 Swap: 1961 > 306 1654 Total: 3988 2283 1705 > > Which indicates that of the 2 GB of RAM, 50 MB are not in use, but about > 1000 MB are available. Notice the line beginning with "-/+ > buffers/cache", subtract the buffers from used, and add the cache to > free to see how much memory would really be available if it's > needed. When I ran the free command, there was about 1050MB > available if needed (about 50 MB free), and about 900 MB used by processes. > > It's not a sign that there's any "leakage", it's the kernel > attempting -- and succeeding most of the time -- to increase the > performance of the machine by caching frequently/recently used data. > > This is explained more in depth at > http://gentoo-wiki.com/FAQ_Linux_Memory_Management > > Jamie > > On Thu, April 27, 2006 12:34 pm, shane wrote: > > Hi All, > > > > > > I have an idle curiousity I'm hoping someone might indulge... > > > > > > I am one of those people who likes to check out 'top' every once in a > > while for no discernable reason. I imagine that it's somewhat like my > > impulse to periodically look in the fridge just to see what's in there. > > > > (yes ha-ha, perhaps I spend a bit too much time with a computer) > > > > > > I've noticed after a re-start, top reports very low numbers, which makes > > sense. Everything is fresh. > > > > Over time, these these numbers grow. Which, I guess is kinda expected as > > well but what I'm curious about is: > > > > Aren't programs supposed free memory after they have used it? > > > > > > Isn't the gradual accumulation of memory usage sign of a memory leak in > > one or more applications (rarely, if ever do I see 'zombies')? > > > > Thanks, > > > > > > Shane > > _______________________________________________ > clug-talk mailing list > [email protected] > http://clug.ca/mailman/listinfo/clug-talk_clug.ca > Mailing List Guidelines (http://clug.ca/ml_guidelines.php) > **Please remove these lines when replying _______________________________________________ clug-talk mailing list [email protected] http://clug.ca/mailman/listinfo/clug-talk_clug.ca Mailing List Guidelines (http://clug.ca/ml_guidelines.php) **Please remove these lines when replying
