A prototype of task spooler which avoids OOM

taskspooler_memory.sh

#!/bin/bash

set -xeu

export max=$((8*1024*1024*1024))  # 8 GB

memory_max() {
    requested=$1
    total=$(
        find /sys/fs/cgroup/user.slice/ -wholename "*/run-*.*/cgroup.procs" |
            datamash dirname 1 |
            xargs -I% cat %/memory.max |
            datamash sum 1
    )
    if [ $((total+requested)) -gt $max ]
    then
      exit 1
    else
      exit 0
    fi
}
export -f memory_max

stresser() {
    size=$((RANDOM%5+1))
    echo | parallel -n0 --limit "memory_max $((size*1024*1024*1024))" -- \
    systemd-run --user --scope --quiet \
        -p MemoryMax=$((size+1))G \
        -p MemorySwapMax=0 \
        --setenv=size=$size -- \
            stress-ng \
                --minimize \
                --timeout $((RANDOM%60+1))s \
                --oomable --no-oom-adjust \
                --memfd 1 --memfd-bytes ${size}G
}
export -f stresser

parallel -n0 --delay 1 --bar -- stresser ::: {1..10}