In Linux, how to tell how much memory processes are using?

Question

I think I may have a memory leak in my LAMP application (memory gets used up, swap starts getting used, etc.). If I could see how much memory the various processes are using

Answer 1

You can use pmap + awk.

Most likely, we're interested in the RSS memory which is the 3rd column in the last line of the example pmap output below (82564).

$ pmap -x 

Address           Kbytes     RSS   Dirty Mode   Mapping

....

00007f9caf3e7000       4       4       4 r----  ld-2.17.so
00007f9caf3e8000       8       8       8 rw---  ld-2.17.so
00007fffe8931000     132      12      12 rw---    [ stack ]
00007fffe89fe000       8       8       0 r-x--    [ anon ]
ffffffffff600000       4       0       0 r-x--    [ anon ]
----------------  ------  ------  ------
total kB          688584   82564    9592

Awk is then used to extract that value.

$ pmap -x  | awk '/total/ { print $4 "K" }'

The pmap values are in kilobytes. If we wanted it in megabytes, we could do something like this.

$ pmap -x  | awk '/total/ { print $4 / 1024 "M" }'