cgroups: document the effect of attaching PID 0 to a cgroup

Document that a pid of zero(0) can be used to refer to the current task
when attaching a task to a cgroup, as in the following usage:

	# echo 0 > /dev/cgroup/tasks

This is consistent with existing cpuset behavior.

Signed-off-by: Li Zefan <[email protected]>
Acked-by: Paul Jackson <[email protected]>
Acked-by: Dhaval Giani <[email protected]>
Cc: Paul Menage <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: Andrea Righi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
1 file changed