admin-guide/cgroup-v1/pids.rst

19 In order to use the `pids` controller, set the maximum number of tasks in
20 pids.max (this is not available in the root cgroup for obvious reasons). The
21 number of processes currently in the cgroup is given by pids.current.
24 to have pids.current > pids.max. This can be done by either setting the limit to
25 be smaller than pids.current, or attaching enough processes to the cgroup such
26 that pids.current > pids.max. However, it is not possible to violate a cgroup
30 To set a cgroup to have no limit, set pids.max to "max". This is the default for
34 pids.current tracks all child cgroup hierarchies, so parent/pids.current is a
35 superset of parent/child/pids.current.
37 The pids.events file contains event counters:
45 First, we mount the pids controller::
47 	# mkdir -p /sys/fs/cgroup/pids
48 	# mount -t cgroup -o pids none /sys/fs/cgroup/pids
52 	# mkdir -p /sys/fs/cgroup/pids/parent/child
53 	# echo 2 > /sys/fs/cgroup/pids/parent/pids.max
54 	# echo $$ > /sys/fs/cgroup/pids/parent/cgroup.procs
55 	# cat /sys/fs/cgroup/pids/parent/pids.current
62 	# cat /sys/fs/cgroup/pids/parent/pids.current
72 	# echo $$ > /sys/fs/cgroup/pids/parent/child/cgroup.procs
73 	# cat /sys/fs/cgroup/pids/parent/pids.current
75 	# cat /sys/fs/cgroup/pids/parent/child/pids.current
77 	# cat /sys/fs/cgroup/pids/parent/child/pids.max
83 We can set a limit that is smaller than pids.current, which will stop any new
85 pids.current)::
87 	# echo 1 > /sys/fs/cgroup/pids/parent/pids.max
90 	# echo 0 > /sys/fs/cgroup/pids/parent/pids.max