Hello,

I was looking at a top and had the idea to make the sum of process memory to see if it top was right.
Here's is the top :

top - 23:26:24 up 1:09, 3 users, load average: 0.00, 0.00, 0.00
Tasks: 28 total, 1 running, 27 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.6% user, 0.3% system, 0.0% nice, 99.1% idle
Mem: 159584k total, 17940k used, 141644k free, 604k buffers
Swap: 248968k total, 0k used, 248968k free, 9816k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
122 root 9 0 2676 2672 1904 S 0.0 1.7 0:00.27 lynx
84 root 9 0 1416 1416 1104 S 0.0 0.9 0:00.06 bash
101 root 14 0 1416 1416 1104 S 0.0 0.9 0:00.08 bash
86 root 9 0 1380 1380 1076 S 0.0 0.9 0:00.04 bash
74 root 9 0 1248 1248 436 S 0.0 0.8 0:00.36 klogd
108 root 8 0 992 988 928 S 0.0 0.6 0:00.01 sh
107 root 9 0 956 952 892 S 0.0 0.6 0:00.01 sh
126 root 15 0 844 840 700 R 2.0 0.5 0:00.02 top
95 root 9 0 812 808 684 S 0.0 0.5 0:00.04 pppd
96 root -1 -20 716 712 592 S 0.0 0.4 0:00.01 pppoa3
97 root -1 -20 716 712 592 S 0.0 0.4 0:00.00 pppoa3
98 root -1 -20 716 712 592 S 0.0 0.4 0:00.08 pppoa3
99 root -1 -20 716 712 592 S 0.0 0.4 0:01.54 pppoa3
113 root 9 0 668 668 512 S 0.0 0.4 0:01.26 less
106 root 9 0 632 632 404 S 0.0 0.4 0:00.00 man
71 root 9 0 592 592 508 S 0.0 0.4 0:00.54 syslogd
93 root 9 0 500 500 440 S 0.0 0.3 0:00.01 modem_run
1 root 9 0 488 488 436 S 0.0 0.3 0:03.76 init
87 root 9 0 404 404 360 S 0.0 0.3 0:00.00 agetty
88 root 9 0 404 404 360 S 0.0 0.3 0:00.00 agetty
89 root 9 0 404 404 360 S 0.0 0.3 0:00.00 agetty
2 root 9 0 0 0 0 S 0.0 0.0 0:00.07 keventd
3 root 9 0 0 0 0 S 0.0 0.0 0:00.00 kapmd
4 root 19 19 0 0 0 S 0.0 0.0 0:00.11 ksoftirqd_CPU0
5 root 9 0 0 0 0 S 0.0 0.0 0:00.00 kswapd
6 root 9 0 0 0 0 S 0.0 0.0 0:00.00 bdflush
7 root 9 0 0 0 0 S 0.0 0.0 0:00.00 kupdated
8 root 9 0 0 0 0 S 0.0 0.0 0:00.00 khubd

In order to get the ram used i sum the RES column which give me : 14300k.
Top tells me that 17940k is used, where are the missing 3640k ?

I've done this top under LFS 5.0 but with knoppix i can't sum all the used memory. My computer is a celeron 333 with 160M Ram.

Thanks.

PS : i know it's a bad idea to go on the web under root, but it was just a test...

I usually just 'cat /proc/meminfo' to find out how much RAM I have...
Looking at your output this line makes me think you have about 160M
Mem: 159584k total, 17940k used, 141644k free, 604k buffers

Ok, maybe i ask my question in a bad way.

I want to know if i can check all the used ram by adding the memory used by each process. In my example, the used is : 17940k and i would like to know how linux get this amount.
I try to add the RES memory for all the processes but it gives me 14300k, so linux should do others things, but what are they ?

Maybe there is little cached memory and buffers in each process and the it's difficult to just make a sum.


Thanks.