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Weird Process, Which one can be disabled? and How?

Hi, Im just upgrade from VPS to dedicated server. In VPS, the RAM usage is about 50MB.

But in this new dedicated server, the RAM usage is more than 400MB

I dont know what process needs too much RAM,

and when looking at top, there's so many unknown process

top - 03:54:51 up 15:35, 1 user, load average: 0.00, 0.00, 0.00
Tasks: 100 total, 1 running, 99 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.1%us, 0.1%sy, 0.0%ni, 99.8%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 2065588k total, 440844k used, 1624744k free, 81392k buffers
Swap: 7823644k total, 0k used, 7823644k free, 294504k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3648 root 15 0 2204 1008 800 R 0.9 0.0 0:00.08 top
1 root 15 0 2072 580 500 S 0.0 0.0 0:00.88 init
2 root RT -5 0 0 0 S 0.0 0.0 0:00.03 migration/0
3 root 34 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/0
4 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/0
5 root RT -5 0 0 0 S 0.0 0.0 0:00.14 migration/1
6 root 34 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/1
7 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/1
8 root RT -5 0 0 0 S 0.0 0.0 0:00.02 migration/2
9 root 34 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/2
10 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/2
11 root RT -5 0 0 0 S 0.0 0.0 0:00.14 migration/3
12 root 39 19 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/3
13 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/3
14 root 10 -5 0 0 0 S 0.0 0.0 0:00.00 events/0
15 root 10 -5 0 0 0 S 0.0 0.0 0:00.00 events/1
16 root 10 -5 0 0 0 S 0.0 0.0 0:00.00 events/2
17 root 10 -5 0 0 0 S 0.0 0.0 0:00.00 events/3
18 root 10 -5 0 0 0 S 0.0 0.0 0:00.01 khelper
19 root 11 -5 0 0 0 S 0.0 0.0 0:00.00 kthread
25 root 10 -5 0 0 0 S 0.0 0.0 0:00.00 kblockd/0
26 root 10 -5 0 0 0 S 0.0 0.0 0:00.00 kblockd/1

27 root 10 -5 0 0 0 S 0.0 0.0 0:00.00 kblockd/2

28 root 10 -5 0 0 0 S 0.0 0.0 0:00.00 kblockd/3

29 root 20 -5 0 0 0 S 0.0 0.0 0:00.00 kacpid

120 root 20 -5 0 0 0 S 0.0 0.0 0:00.00 cqueue/0

121 root 20 -5 0 0 0 S 0.0 0.0 0:00.00 cqueue/1

122 root 20 -5 0 0 0 S 0.0 0.0 0:00.00 cqueue/2

So, Which one can be disabled? and How?

Thanks in advance

(The server running CentOS 5.3)

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3 Answers 3

They can't, or at least they shouldn't. All of them apart from top and init (from your listing) are kernel processes, and init is the parent process (either directly or indirectly) of everything running on your linux box. If you also observe the VIRT/RES columns of your top output, most of the processes you list have 0 in these columns, they don't contribute towards your memory usage in any traditional way.

Your "actual" memory usage is closer to 64Mb ( used - buffers - cached ). Buffers/cache are used by the linux kernel to i.e. cache the filesystem. Unused ram is wasted ram, hence the kernel uses it for buffers/cache, the ram will be made available if an application requests it.

See also this serverfault question, which posts some links to understanding linux memory management/usage.

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All the processes you list (typically those ending with /1 and /2) are all kernel threads they are linked with functionality in the kernel and most of them you can't or you don't really want to disabled. ksoftirqd is processing software interrupts (/0 means running on the first cpu, /0 running on the 2nd cpu. ...), watchdog/0 takes care of the watchdog chip, and so forth ...

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I'm certainly not an expert but I was under the impression that free memory is used to pre-cache files from the HDD to improve system performance.

I'm sure someone on here can give you a better answer though...

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