Cpuset.cpus updated only in payload path but not in monitor path

LXC
1

Hello,
I am using the following call to update cpuset.cpus to “0-3” (on lxc v4.0.6)

char *name = containers[i];
c = lxc_container_new(name, LXC_PATH);
if (NULL != c) {
	if (!c->set_cgroup_item(c, "cpuset.cpus", str_max_cpuset)) {
		res = -1;
		sm_error("Failed to assign '%s' value to 'cpuset.cpus' for '%s'",str_max_cpuset, name);
	}
	lxc_container_put(c);
}

but only “cpuset.cpus” under payload path was updated the “cpuset.cpus” under monitor path was kept to 0.

#cat /sys/fs/cgroup/cpuset/lxc.payload.MyContainer1/cpuset.cpus
0-3
#cat /sys/fs/cgroup/cpuset/lxc.monitor.MyContainer1/cpuset.cpus
0

If I use:
lxc-cgroup -n MyContainer1 -P /mnt/settings/lxc cpuset.cpus “0-3”
only the payload path is changed:

#cat /sys/fs/cgroup/cpuset/lxc.payload.MyContainer1/cpuset.cpus
0-3
#cat /sys/fs/cgroup/cpuset/lxc.monitor.MyContainer1/cpuset.cpus
0

Any idea please?
Thanks

2

Any thoughts @amikhalitsyn ?

3

@Med_Fodha that’s correct behavior. lxc.payload cgroup is for the container process tree itself, but lxc.monitor is for container manager.

1 Like
4

Which lxc api is used to change the cpuset for the container manager? or we have to use echo "0-3" > /sys/fs/cgroup/cpuset/lxc.monitor.MyContainer1/cpuset.cpus, is there really an advantage to modify cpuset for the monitor?
At boot time both payload and monitor are set to 0-3 but after resuming from suspend we have to restore the value to “0-3”(because after resume both cpuset for payload and monitor are set to 0). I succeeded to do it for payload through lxc api but it is not the case for monitor

5

AFAIR there is no lxcapi for such case because it makes no sense to change cgroup limits for the monitor.

1 Like