Documentation: update cgroup pid and cpuset information

The cgroup documentation does not specify how a process can be removed
from a particular group.  This patch adds a note at the end of the
simple example about how this is done.  Also, some cgroups (like
cpusets) require user input before a new group can be used.  This is
noted in the patch as well.

Signed-off-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Eric B Munson 2011-03-15 16:12:18 -07:00 committed by Linus Torvalds
parent ca3b78aa16
commit bb6405eab2
1 changed files with 12 additions and 0 deletions

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@ -349,6 +349,10 @@ To mount a cgroup hierarchy with all available subsystems, type:
The "xxx" is not interpreted by the cgroup code, but will appear in The "xxx" is not interpreted by the cgroup code, but will appear in
/proc/mounts so may be any useful identifying string that you like. /proc/mounts so may be any useful identifying string that you like.
Note: Some subsystems do not work without some user input first. For instance,
if cpusets are enabled the user will have to populate the cpus and mems files
for each new cgroup created before that group can be used.
To mount a cgroup hierarchy with just the cpuset and memory To mount a cgroup hierarchy with just the cpuset and memory
subsystems, type: subsystems, type:
# mount -t cgroup -o cpuset,memory hier1 /dev/cgroup # mount -t cgroup -o cpuset,memory hier1 /dev/cgroup
@ -426,6 +430,14 @@ You can attach the current shell task by echoing 0:
# echo 0 > tasks # echo 0 > tasks
Note: Since every task is always a member of exactly one cgroup in each
mounted hierarchy, to remove a task from its current cgroup you must
move it into a new cgroup (possibly the root cgroup) by writing to the
new cgroup's tasks file.
Note: If the ns cgroup is active, moving a process to another cgroup can
fail.
2.3 Mounting hierarchies by name 2.3 Mounting hierarchies by name
-------------------------------- --------------------------------