#!/bin/bash
if [ $(id -u) -ne 0 ]; then
    echo "must be run as root"
    exit 1
fi

for U in $(ps -e -o user | tail -n +2 | sort | uniq); do
    TOTAL_RSS=0
    PS_COUNT=0

    while read CPID CRSS; do
        PS_COUNT=$(expr ${PS_COUNT} + 1)
        TOTAL_RSS=$(expr ${TOTAL_RSS} + ${CRSS})
        MAX_RSS=${CRSS}
        MAX_RSS_PID=${CPID}
    done < <(ps -u ${U} -o pid,rss | tail -n +2 | sort -n -k 2)

    if [ ${PS_COUNT} -gt 0 ]; then
        AVGRSS=$(expr ${TOTAL_RSS} / ${PS_COUNT})
        echo "${U} ${PS_COUNT} ${TOTAL_RSS}"

        if [ ${MAX_RSS} -gt $(expr ${AVGRSS} "*" 2) ]; then
            echo -e "\tpid ${MAX_RSS_PID} has ${MAX_RSS}, will terminate"
            kill -s SIGTERM ${MAX_RSS_PID}
            sleep 2
            kill -s SIGKILL ${MAX_RSS_PID}
        fi
    fi
done