Stephane posted a patchset to add perf_cgroup subsystem, so perf can be used to monitor all threads belonging to a cgroup. But if you already mounted a cgroup hierarchy but without perf_cgroup and the hierarchy has sub-cgroups, you can't bind perf_cgroup to it, and thus you're not able to use per-cgroup perf feature. This patchset alleviates the pain, and then a subsytem can be bound/unbound to/from a hierarchy which has sub-cgroups in it. Some subsystems still can't take advantage of this patchset, memcgroup and cpuset for example. For cpuset, if a hierarchy has a sub-cgroup and the cgroup has tasks, we can't decide sub-cgroup's cpuset.mems and cpuset.cpus automatically if we try to bind cpuset to this hierarchy. For memcgroup, memcgroup uses css_get/put(), and due to some complexity, for now bindable subsystems should not use css_get/put(). Usage: # mount -t cgroup -o cpuset xxx /mnt # mkdir /mnt/tmp # echo $$ > /mnt/tmp/tasks (add cpuacct to the hierarchy) # mount -o remount,cpuset,cpuacct xxx /mnt (remove it from the hierarchy) # mount -o remount,cpuset xxx /mnt There's another limitation, cpuacct should not be bound to any mounted hierarchy before the above operation. But that's not a problem, as you can remove it from a hierarchy and bind it to another one. Changelog v2: - Fix some bugs. - Spit can_bind flag to bindable and unbindable flags - Provide a __css_tryget() so a bindable subsystem can pin a cgroup via it. - ... --- Documentation/cgroups/cgroups.txt | 37 +++- include/linux/cgroup.h | 39 +++- kernel/cgroup.c | 391 +++++++++++++++++++++++++++++++------ kernel/cgroup_freezer.c | 1 + kernel/sched.c | 2 + security/device_cgroup.c | 2 + 6 files changed, 398 insertions(+), 74 deletions(-) _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
