Provide a usage example, and update the bind() callback API. Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx> --- Documentation/cgroups/cgroups.txt | 26 +++++++++++++++++--------- 1 files changed, 17 insertions(+), 9 deletions(-) diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt index 190018b..5b5382a 100644 --- a/Documentation/cgroups/cgroups.txt +++ b/Documentation/cgroups/cgroups.txt @@ -363,17 +363,23 @@ Note this will add ns to the hierarchy but won't remove memory or cpuset, because the new options are appended to the old ones: # mount -o remount,ns /dev/cgroup +For some subsystems you can bind them to a mounted hierarchy or +remove them from it, even if there're sub-cgroups in it: +# mount -t cgroup -o freezer hier1 /dev/cgroup +# echo $$ > /dev/cgroup/my_cgroup +# mount -o freezer,cpuset hier1 /dev/cgroup +(failed) +# mount -o freezer,cpuacct hier1 /dev/cgroup +# mount -o cpuacct hier1 /dev/cgroup + +Note cpuacct should be sit in the default hierarchy before remount. + To Specify a hierarchy's release_agent: # mount -t cgroup -o cpuset,release_agent="/sbin/cpuset_release_agent" \ xxx /dev/cgroup Note that specifying 'release_agent' more than once will return failure. -Note that changing the set of subsystems is currently only supported -when the hierarchy consists of a single (root) cgroup. Supporting -the ability to arbitrarily bind/unbind subsystems from an existing -cgroup hierarchy is intended to be implemented in the future. - Then under /dev/cgroup you can find a tree that corresponds to the tree of the cgroups in the system. For instance, /dev/cgroup is the cgroup that holds the whole system. @@ -623,13 +629,15 @@ initialization which might be required before a task could attach. For example in cpusets, no task may attach before 'cpus' and 'mems' are set up. -void bind(struct cgroup_subsys *ss, struct cgroup *root) +void bind(struct cgroup_subsys *ss, struct cgroup *cgrp, bool unbind) (cgroup_mutex and ss->hierarchy_mutex held by caller) Called when a cgroup subsystem is rebound to a different hierarchy -and root cgroup. Currently this will only involve movement between -the default hierarchy (which never has sub-cgroups) and a hierarchy -that is being created/destroyed (and hence has no sub-cgroups). +and root cgroup. For some subsystems this will only involve movement +between the default hierarchy (which never has sub-cgroups) and a +hierarchy that is being created/destroyed (and hence has no sub-cgroups). +For some other subsystems this can involve movement between the default +hierarchy and a mounted hierarchy which may have sub-cgroups in it. 4. Questions ============ -- 1.7.0.1 _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
