How to find out which processes are using swap space in Linux?

Question

Under Linux, how do I find out which process is using the swap space more?

Answer 1

I adapted a different script on the web to this long one-liner:

 { date;for f in /proc/[0-9]*/status; do 
   awk '{k[$1]=$2} END { if (k["VmSwap:"]) print k["Pid:"],k["Name:"],k["VmSwap:"];}' $f 2>/dev/null; 
   done | sort -n ; }

Which I then throw into a cronjob and redirect output to a logfile. The information here is the same as accumulating the Swap: entries in the smaps file, but if you want to be sure, you can use:

{ date;for m in /proc/*/smaps;do 
  awk '/^Swap/ {s+=$2} END { if (s) print FILENAME,s }' $m 2>/dev/null;
  done | tr -dc ' [0-9]\n' |sort -k 1n; }

The output of this version is in two columns: pid, swap amount. In the above version, the tr strips the non-numeric components. In both cases, the output is sorted numerically by pid.