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- - How to get the memory taken by each process? (https://www.linuxquestions.org/questions/linux-newbie-8/how-to-get-the-memory-taken-by-each-process-4175427188/)

liuwenbin168@126.com

09-14-2012 02:40 AM

How to get the memory taken by each process?

Hi gurus,

I am new to Linux, and here is a dumb question:
How can I see the memory taken by each process?

Why this question:
I have a server (CentOS 5.8), its total memory is 32 GB, and now the used memory is more than 31 GB, so I want to get which process takes most memory.
Meantime, if I can see all of the memory taken for every process, that would be best!

Till to now, what I did:
1. free -m

Code:

[root@ID5xinyong ~]# free -m

  total used free shared buffers cached

Mem: 32108 31579 528 0 6 43

-/+ buffers/cache: 31529 579

Swap: 34287 114 34173

As the output says, more than 31 GB memory has been used.

2.

Code:

top -c, then press: M

-----------------------------------------------------------------------------------------

  top - 15:03:46 up 30 days, 21 min, 2 users, load average: 0.00, 0.00, 0.00

Tasks: 351 total, 1 running, 350 sleeping, 0 stopped, 0 zombie

Cpu(s): 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st

Mem: 32878968k total, 32339300k used, 539668k free, 7304k buffers

Swap: 35110904k total, 117036k used, 34993868k free, 44916k cached



  PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND

 3186 mqm 20 0 1498m 10m 10m S 0.0 0.0 2:19.81 /opt/mqm/bin/amqzmuc0 -m QM1

19357 mqm 20 0 1498m 10m 9.9m S 0.0 0.0 1:54.99 /opt/mqm/bin/amqzmuc0 -m QM2

 3234 mqm 20 0 935m 4284 3772 S 0.0 0.0 10:41.55 /opt/mqm/bin/amqzlaa0 -mQM1 -fip0

29364 root 20 0 97756 3888 2940 S 0.0 0.0 0:00.19 sshd: root@pts/1

29276 root 20 0 97756 3872 2940 S 0.0 0.0 0:00.14 sshd: root@pts/0

...

-----------------------------------------------------------------------------------------

As the top command output, the %MEM column has been sorted descending, but, I still cannot see the BIG process who takes much memory.

So, the dumb question is how to get the process who takes lots of memory.

Thanks in advance!

Celyr

09-14-2012 02:50 AM

Quote:

Originally Posted by liuwenbin168@126.com (Post 4780006)

Code:

[root@ID5xinyong ~]# free -m

  total used free shared buffers cached

Mem: 32108 31579 528 0 6 43

-/+ buffers/cache: 31529 579

Swap: 34287 114 34173

You are not seeing any process taking all that ram because actually there isn't one. You ram is just being cached by the linux kernel but is going to be freed if needed.
You are using very low ram on that server. :)

For example this is one of my boxes:

Code:

root@minnie:~# free -m

            total      used      free    shared    buffers    cached

Mem:          3943      3691        252          0        169      3292

-/+ buffers/cache:        228      3714

Swap:            0          0          0

root@minnie:~# ps aux | sort -b -k 4 | tail

root      2055  0.0  0.0  53308  3236 ?        Ss  Aug25  0:04 /usr/sbin/cupsd -C /etc/cups/cupsd.conf

root      2078  0.0  0.0  73404  3632 ?        Ss  Aug25  0:05 /usr/sbin/smbd -D

root      2081  0.0  0.0  73532  1940 ?        S    Aug25  0:00 /usr/sbin/smbd -D

root      6157  0.0  0.0 101256  980 ?        Ssl  Sep09  0:55 /sbin/apcupsd

data      615  0.0  0.0 152260  3436 ?        Ssl  Sep13  0:01 xxx

root      2026  0.0  0.0 184420  2432 ?        Sl  Aug25  0:00 /usr/libexec/polkitd --no-debug

root      1959  0.0  0.0 2081116 2620 ?        Ssl  Aug25  0:00 /usr/sbin/console-kit-daemon

root      2086  0.0  0.1  13556  6764 ?        Ss  Aug25  0:05 /usr/sbin/dhcpd

data      2106  0.0  0.5 263756 22476 ?        Ssl  Aug25  24:36 xxx

root      5268  0.0  0.9 372712 39396 ?        Ssl  Aug26  2:12 /usr/sbin/named

root@minnie:~#

As you see it may appear that there is only 200MB of free ram, this is true but there are at 3,2GB that can be released by the kernel if needed.

However there is something that i can't understand about your free output, can you post a

Code:

# cat /proc/meminfo

and

Code:

vmstat

It looks like your server is doing big I/O is this true ?

liuwenbin168@126.com

09-14-2012 03:00 AM

Quote:

Originally Posted by Celyr (Post 4780010)

Hi Celyr,
Thanks A Lot for your quick reply!

You mean the linux kernel cached lots of RAM? And how can I know how much RAM it cached?

Let's say the output of "free -m", the first line:

Code:

--------------------------------------------

    total used    free  shared  buffers cached

Mem: 32108 31579  528  0      6        43

--------------------------------------------

Does not it mean that only 43 mb are being cached (by kernel)? If not, how to understand the value for "cached 43"?

Thank you very much!

syg00

09-14-2012 03:05 AM

@liuwenbin168@126.com, in future use [code] tags as @Celyr has - it retains data formatting and makes it easier (and more likely) others will try to help.

As for your problem, RAM gets used for all sorts of things by the kernel and products (like Oracle e.g.).
Lets see the output from

Code:

cat /proc/meminfo

. Use code tags or else you may get ignored.

liuwenbin168@126.com

09-14-2012 03:09 AM

Hi Celyr,

Outputs of the commands you adviced:

Code:

----------------------------------------------------

[root@ID5xinyong ~]# cat /proc/meminfo

MemTotal:      32878968 kB

MemFree:          537932 kB

Buffers:            7976 kB

Cached:            45012 kB

SwapCached:        5660 kB

Active:            33416 kB

Inactive:          33304 kB

Active(anon):      19464 kB

Inactive(anon):    16900 kB

Active(file):      13952 kB

Inactive(file):    16404 kB

Unevictable:          0 kB

Mlocked:              0 kB

SwapTotal:      35110904 kB

SwapFree:      34993868 kB

Dirty:                16 kB

Writeback:            0 kB

AnonPages:        12352 kB

Mapped:            32256 kB

Shmem:            22596 kB

Slab:              80952 kB

SReclaimable:      17164 kB

SUnreclaim:        63788 kB

KernelStack:        4296 kB

PageTables:        10052 kB

NFS_Unstable:          0 kB

Bounce:                0 kB

WritebackTmp:          0 kB

CommitLimit:    47978676 kB

Committed_AS:    724816 kB

VmallocTotal:  34359738367 kB

VmallocUsed:    4536520 kB

VmallocChunk:  34329520624 kB

HardwareCorrupted:    0 kB

AnonHugePages:        0 kB

HugePages_Total:    3488

HugePages_Free:    3488

HugePages_Rsvd:        0

HugePages_Surp:        0

Hugepagesize:      2048 kB

DirectMap4k:      10240 kB

DirectMap2M:    33544192 kB

----------------------------------------------------

Code:

[root@ID5xinyong ~]# vmstat

procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----

 r  b  swpd  free  buff  cache  si  so    bi    bo  in  cs us sy id wa st

 0  0 117036 537856  7992  45012  243  61  253    67    0    0  3  1 87  9  0



----------------------------------------------------

Yes, it looks like my server is doing I/O frequently, but sorry, I am not running any special programs on it.
As the value of : swap in/out, data is being swapped in and swapped out quickly, is it also meaning that there is some fishy process?

liuwenbin168@126.com

09-14-2012 03:20 AM

Quote:

Originally Posted by syg00 (Post 4780020)

Code:

cat /proc/meminfo

. Use code tags or else you may get ignored.

Thank you, syg00, I will be happy to follow the rule of our forum.

syg00

09-14-2012 03:50 AM

Much more readable.
It is not a rule - merely common courtesy. If you want people to read your posts, make it easy for them to help you.

You have almost 7 Gig reserved for huge pages - which aren't (currently) being used. They can be disabled (at boot), but we can't know if that will affect whatever you are running on that system. Google should help.
Personally I'd be inclined to turn it off and see what happens - but it's not my system.

chrism01

09-14-2012 04:59 AM

I also recommend reading http://www.linuxatemyram.com/

Celyr

09-14-2012 05:27 AM

There is still something not clear to me, ok 7GB reserved for huge_page but i still think there is something wired.
can you do:

Code:

# ps aux | sort -b -k 4 | tail

and

Code:

# mount | grep ram

Code:

# mount | grep tmp

liuwenbin168@126.com

09-14-2012 05:31 AM

Quote:

Originally Posted by syg00 (Post 4780064)

Hi syg00, Thanks Very Much for pointing out my problem, my RAM issue is probably caused by huge page configuration.

Yes, my system performance slow down when I configured huge pages for it.

I need to learn more knowledge on Huge Pages then I think I will be clear on this problem.

Thanks again and have a nice day pls!

liuwenbin168@126.com

09-14-2012 05:38 AM

Quote:

Originally Posted by Celyr (Post 4780130)

There is still something not clear to me, ok 7GB reserved for huge_page but i still think there is something wired.
can you do:

Code:

# ps aux | sort -b -k 4 | tail

and

Code:

# df -h | grep ram

Code:

# df -h | grep tmp

Hi Celyr,

Here are the prints for these commands:

Code:

ps aux | sort -b -k 4 | tail



[root@ID5xinyong ~]# ps aux | sort -b -k 4 | tail

postfix  1508  0.0  0.0  78860  208 ?        S    Aug15  0:07 qmgr -l -t fifo -u

mqm      3202  0.0  0.0 832136  1460 ?        Sl  Aug15  1:00 /opt/mqm/bin/amqzmuf0 -m QM1

mqm      19373  0.0  0.0 832136  1460 ?        Sl  Aug27  0:34 /opt/mqm/bin/amqzmuf0 -m QM2

root      1303  0.0  0.0  93156  336 ?        S<sl Aug15  0:05 auditd

mqm      3234  0.0  0.0 958228  4284 ?        Sl  Aug15  10:42 /opt/mqm/bin/amqzlaa0 -mQM1 -fip0

mqm      19407  0.0  0.0 959368  2268 ?        Sl  Aug27  1:39 /opt/mqm/bin/amqzlaa0 -mQM2 -fip0

dbus      1340  0.0  0.0  97148    8 ?        Ssl  Aug15  0:00 dbus-daemon --system

root    29276  0.0  0.0  97756  3876 ?        S    13:22  0:00 sshd: root@pts/0

root    29364  0.0  0.0  97756  3892 ?        S    13:40  0:00 sshd: root@pts/1

USER      PID %CPU %MEM    VSZ  RSS TTY      STAT START  TIME COMMAND

Code:

df -h | grep ram



[root@ID5xinyong ~]# df -h | grep ram

[root@ID5xinyong ~]#

This prints nothing when I issued it.

Code:

df -h | grep tmp

[root@ID5xinyong ~]# df -h | grep tmp

tmpfs                  16G    0  16G  0% /dev/shm

Code:

[root@ID5xinyong ~]# df -h

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/vg_id5xinyong-lv_root

                      50G  9.0G  38G  20% /

tmpfs                  16G    0  16G  0% /dev/shm

/dev/sda1            485M  31M  429M  7% /boot

/dev/mapper/vg_id5xinyong-lv_home

                      361G  28G  315G  9% /home

Is there anything special we can get from these prints?

Thanks a lot!!

liuwenbin168@126.com

09-14-2012 05:40 AM

Quote:

Originally Posted by chrism01 (Post 4780121)

I also recommend reading http://www.linuxatemyram.com/

Thank you, chrism01, I will read the recommended staff.

Celyr

09-14-2012 06:21 AM

Quote:

Originally Posted by liuwenbin168@126.com (Post 4780140)

Is there anything special we can get from these prints?

Thanks a lot!!

I can't get anything sorry, but the situation keeps looking wired to me. The only think that I can suggest to you is to keep investigating and to lower down the number of huge pages

Code:

echo number > /proc/sys/vm/nr_hugepages

Where number can be even 10 since you are not using them at all

How many processes are you running ?

Code:

ps aux | wc -l

As you may have seen i have modified the post because ramfs doesn't get printed on df -h, try to see if you have ramfs mounted

Code:

mount | grep ramfs

liuwenbin168@126.com

09-14-2012 07:00 AM

Quote:

Originally Posted by Celyr (Post 4780172)

I can't get anything sorry, but the situation keeps looking wired to me. The only think that I can suggest to you is to keep investigating and to lower down the number of huge pages

Code:

echo number > /proc/sys/vm/nr_hugepages

Where number can be even 10 since you are not using them at all

How many processes are you running ?

Code:

ps aux | wc -l

As you may have seen i have modified the post because ramfs doesn't get printed on df -h, try to see if you have ramfs mounted

Code:

mount | grep ramfs

Hi Celyr,
Since I have finished work and I am at home now, I cannot run the commands you provided right now, but I will do it on Monday, and then post the prints here.

I do THANKS A MILLION for you teacher's great patience! You're really a nice man, thanks and have a nice weekend please!

liuwenbin168@126.com

09-16-2012 08:11 PM

Quote:

Originally Posted by Celyr (Post 4780172)

I can't get anything sorry, but the situation keeps looking wired to me. The only think that I can suggest to you is to keep investigating and to lower down the number of huge pages

Code:

echo number > /proc/sys/vm/nr_hugepages

Where number can be even 10 since you are not using them at all

How many processes are you running ?

Code:

ps aux | wc -l

As you may have seen i have modified the post because ramfs doesn't get printed on df -h, try to see if you have ramfs mounted

Code:

mount | grep ramfs

Hi Celyr,

Code:

[root@ID5xinyong ~]# echo number > /proc/sys/vm/nr_hugepages



<This is what I got:>  -bash: echo: write error: Invalid argument



and FYI:



[root@ID5xinyong ~]# cat /proc/sys/vm/nr_hugepages

3488

Code:

[root@ID5xinyong ~]# ps aux | wc -l

352

Too many processes are running. May I know how many processes are there in common? Thanks!

"mount | grep ramfs" still returns nothing.

Code:

[root@ID5xinyong ~]# mount | grep ramfs

[root@ID5xinyong ~]#

What else I can do to clarify my issue?

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