Messages in this thread Patch in this message | | | From | Witold Krecicki <> | Subject | [PATCH 6/6] cgroup: documentation of isolation_root cgroup flag | Date | Fri, 30 Sep 2011 13:36:25 +0200 |
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Documentation of isolation_root cgroup flag.
Signed-off-by: Witold Krecicki <wpk@culm.net> --- Documentation/cgroups/cgroups.txt | 20 ++++++++++++++++++-- 1 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt index cd67e90..66880a6 100644 --- a/Documentation/cgroups/cgroups.txt +++ b/Documentation/cgroups/cgroups.txt @@ -19,7 +19,8 @@ CONTENTS: 1.3 How are cgroups implemented ? 1.4 What does notify_on_release do ? 1.5 What does clone_children do ? - 1.6 How do I use cgroups ? + 1.6 What does isolation_root do ? + 1.7 How do I use cgroups ? 2. Usage Examples and Syntax 2.1 Basic Usage 2.2 Attaching processes @@ -304,7 +305,22 @@ subsystem of the newly created cgroup. Usually when this callback is implemented for a subsystem, it copies the values of the parent subsystem, this is the case for the cpuset. -1.6 How do I use cgroups ? +1.6 What does isolation_root do ? +--------------------------------- + +If the isolation_root flag is enabled (1) in a cgroup, then all tasks +in this cgroup and its children will see this group as its top group +in /proc/$PID/cgroup. Also mounts of cgroup filesystem performed by a task +in isolation root cgroup will see isolation root cgroup as top cgroup. +It is impossible for a task to exit isolated root. Flag may only be set or +cleared when the cgroup is not in use. +The preffered way to use isolation_root for containers (eg. lxc) is to +create 'master' cgroup - /sys/fs/cgroup/cpu/container_name with settings +for the container, then create /sys/fs/cgroup/cpu/container_name/root with +isolation_root flag set and add the 'init' task for the container to +this cgroup. + +1.7 How do I use cgroups ? -------------------------- To start a new job that is to be contained within a cgroup, using -- 1.7.4.1
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