Messages in this thread | | | Date | Fri, 22 Oct 2010 16:09:08 +0800 | From | Li Zefan <> | Subject | [PATCH 0/7] cgroups: Allow to bind/unbind subsystems to/from non-trival hierarchy |
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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 in specific.
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.
--- Documentation/cgroups/cgroups.txt | 26 ++- include/linux/cgroup.h | 25 +++- kernel/cgroup.c | 305 +++++++++++++++++++++++++++++++------ kernel/cgroup_freezer.c | 19 ++- kernel/sched.c | 1 + net/sched/cls_cgroup.c | 1 + security/device_cgroup.c | 1 + 7 files changed, 311 insertions(+), 67 deletions(-)
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