Which processes swaps memory

Question

I can see swap's total, used, free etc. sizes from top command.
But I can't figure out which process uses swap, is it possible to find out swap memory by process?

I'm running CentOS 6.3.

Answer 1

You could use ps and some quick awk maths to gain the answer.

The command that you can use is this...

$ ps -eo rss,vsz,pid,cmd | awk '{print $2-$1,$0}' | sort -nr | head

The first column out the output should be the swap usage.

rss / resident set size

resident set size, the non-swapped physical memory that a task has used (inkiloBytes). (alias rssize, rsz).

vsz / virtual memory size

virtual memory size, the process in KiB (1024-byte units). Device mappings are currently excluded; this is subject to change.

Awk maths

If rss (Column 1) is the non swapped memory and vsz(Column 2) is the physical memory, then..

swap = vsz - rss