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authorTejun Heo <tj@kernel.org>2012-11-09 09:12:29 -0800
committerTejun Heo <tj@kernel.org>2012-11-09 09:12:29 -0800
commita8638030f668884720b8f4456448d0ce33952b05 (patch)
tree2532b2ef9def879513fad0e304a6a9c98fa798f0 /include/linux/cgroup.h
parent316eb661f125397d46f16f94e3c81ad3dc4c1233 (diff)
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cgroup: add cgroup_subsys->post_create()
Currently, there's no way for a controller to find out whether a new cgroup finished all ->create() allocatinos successfully and is considered "live" by cgroup. This becomes a problem later when we add generic descendants walking to cgroup which can be used by controllers as controllers don't have a synchronization point where it can synchronize against new cgroups appearing in such walks. This patch adds ->post_create(). It's called after all ->create() succeeded and the cgroup is linked into the generic cgroup hierarchy. This plays the counterpart of ->pre_destroy(). When used in combination with the to-be-added generic descendant iterators, ->post_create() can be used to implement reliable state inheritance. It will be explained with the descendant iterators. v2: Added a paragraph about its future use w/ descendant iterators per Michal. v3: Forgot to add ->post_create() invocation to cgroup_load_subsys(). Fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Glauber Costa <glommer@parallels.com>
Diffstat (limited to 'include/linux/cgroup.h')
-rw-r--r--include/linux/cgroup.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index fe876a77031a..b4421221111d 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -438,6 +438,7 @@ int cgroup_taskset_size(struct cgroup_taskset *tset);
struct cgroup_subsys {
struct cgroup_subsys_state *(*create)(struct cgroup *cgrp);
+ void (*post_create)(struct cgroup *cgrp);
void (*pre_destroy)(struct cgroup *cgrp);
void (*destroy)(struct cgroup *cgrp);
int (*can_attach)(struct cgroup *cgrp, struct cgroup_taskset *tset);