From bb6405eab2a408c46949b3353ecfa1126caa3af2 Mon Sep 17 00:00:00 2001 From: Eric B Munson Date: Tue, 15 Mar 2011 16:12:18 -0700 Subject: [PATCH] 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 Acked-by: Paul Menage Signed-off-by: Randy Dunlap Signed-off-by: Linus Torvalds --- Documentation/cgroups/cgroups.txt | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt index 44b8b7af8019..cbdfb7d9455b 100644 --- a/Documentation/cgroups/cgroups.txt +++ b/Documentation/cgroups/cgroups.txt @@ -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 /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 subsystems, type: # 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 +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 --------------------------------