Re: Memory usage

From: Jason Riedy <>
Date: Wed, 01 Apr 1998 22:28:03 -0500

Oh well. And "Khuanchai Supparatpinyo" writes: -
 - My question is why the mallinfo total memory (36850 KB) is much less than
 - total memory by TOP (127840 KB). Is this abnormal?

Not in a system that uses free memory as file system cache. If you're
displaying through X, try xmem or xosview or something like that. The
free command will also split up the memory for you. Actually, your
top output shows alost half your memory in use as file cache (buffer).

If you don't believe the number reported for the buffers, try checking
before and after you run a ``find / -name DNE'' on an unloaded machine.
You'll see the amount used for buffers grow.

BTW, for anyone using Solaris, I greatly encourage you to go check the
Performance Q/A column on SunWorld. The RMCmem package is very handy,
but beware the GUI on a loaded system. Actually, the column's probably
good reading for any OS.

 - I notice that the total free reported from mallinfo is only 2%; how should
 - I correct the problem?

In general, a low free space (but not swapping) doesn't mean anything.
Because your memory is mostly used for file cache, the best way to see
if you have enough (or too much) memory is to watch the vmstat output.
I believe the columns of interest on Linux are `bi' and `bo'. If you
have very little activity, you might have too much memory. I don't
know if there's a way to check the age of the file buffers...

Received on Wed Apr 01 1998 - 19:33:26 MST

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