[root@localhost ~]# cat /usr/bin/cgroup_swappiness_set.sh
#!/bin/sh

CGROUP_V1_MEMORY_DIR=$(mount | grep "^cgroup .*memory" | cut -d ' ' -f 3)

if [ -z $CGROUP_V1_MEMORY_DIR ]; then
	exit -22  # EINVAL
fi

GLOBAL_SWAPPINESS=$(cat /proc/sys/vm/swappiness)
for cg in $(find $CGROUP_V1_MEMORY_DIR -name memory.swappiness); do
	echo $GLOBAL_SWAPPINESS > $cg
done

[root@localhost ~]# chmod +x /usr/bin/cgroup_swappiness_set.sh

[root@localhost ~]# cat /usr/lib/systemd/system/swappiness_fix.service
[Unit]
Description=Set all existing -v1 memory cgroups to global vm.swappiness
After=systemd-sysctl.service

[Service]
Type=oneshot
ExecStart=/usr/bin/cgroup_swappiness_set.sh

[Install]
WantedBy=multi-user.target

[root@localhost ~]# systemctl enable swappiness_fix.service