Run Gentoo Portage in a cpu cgroup

make.conf

PORTAGE_IONICE_COMMAND="/usr/local/sbin/portage-cgroup \${PID}"

portage-cgroup

#!/bin/sh

CGROUP_CPU_ROOT="/sys/fs/cgroup/cpu"
PORTAGE_CPU_SHARES=512

# $1 must be the portage PID
[ -n "$1" ] || exit 1

echo "/usr/local/sbin/remove-empty-cpu-cgroup" > "${CGROUP_CPU_ROOT}/release_agent"

cgroup=$(mktemp -d --tmpdir="${CGROUP_CPU_ROOT}" portage-XXXX) &&
echo $1 > "${cgroup}/tasks" &&
echo 1 > "${cgroup}/notify_on_release" &&
echo ${PORTAGE_CPU_SHARES} > "${cgroup}/cpu.shares"

remove-empty-cpu-cgroup

#!/bin/sh

CGROUP_CPU_ROOT="/sys/fs/cgroup/cpu"

[ -n "${1}" ] || exit 1

cgroup="${CGROUP_CPU_ROOT}/${1}"
rmdir "${cgroup}"