Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: text/plain;
	charset="us-ascii"
Content-Transfer-Encoding: 8BIT
Subject: Question about free/used memory on Linux
Date: Sun, 21 Oct 2007 10:54:38 -0700
Message-ID: <FA6FB5FA4DA6BF4386D129273B2E3EC3024B847B@xmb-sjc-214.amer.cisco.com>
Thread-Topic: Question about free/used memory on Linux
Thread-Index: AcgUC3Io6vvmU09DQqCCnWOwYptTZA==
From: "Ravinandan Arakali (rarakali)" <rarakali@cisco.com>
To: "Linux Kernel" <linux-kernel@vger.kernel.org>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1074
Lines: 27

Hi kernel gurus,
I am trying to find out the memory that's used on my linux box.
I find that there are quite a few confusing metrics. How do
I find out the "true" used memory ?

1. For eg. "free -m" shows free memory (excluding buffers/caches) 
as 308 MB while I can see(from "df" output) that the the tmpfs 
partitions take up about 400 MB. So, does "free -m" not consider 
the tmpfs partitions ?

2. I try to add up RSS field of all processes reported by
"ps aux" command. But is it true that this would be misleading
in that, shared memory used by, say 2 processes would show
up twice here although there's only one copy in memory. Also
does this consider the fact that there's only one copy
of shared libraries ?

3. I guess "free -m" and "top" commands use /proc/meminfo 
and hence all these outputs are same ?

Thanks,
Ravi
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/