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author | Li Zefan <lizf@cn.fujitsu.com> | 2008-04-29 08:00:13 (GMT) |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-29 15:06:10 (GMT) |
commit | e8d55fdeb882cfcb5e8db5a5ce16edfba78aafc5 (patch) | |
tree | 0c0a7338d8adb2aaf4310eb89d1679c802ea617d /kernel/cgroup.c | |
parent | 472b1053f3c319cc60bfb2a0bb062fed77a93eb6 (diff) | |
download | linux-fsl-qoriq-e8d55fdeb882cfcb5e8db5a5ce16edfba78aafc5.tar.xz |
cgroups: simplify init_subsys()
We are at system boot and there is only 1 cgroup group (i,e, init_css_set), so
we don't need to run through the css_set linked list. Neither do we need to
run through the task list, since no processes have been created yet.
Also referring to a comment in cgroup.h:
struct css_set
{
...
/*
* Set of subsystem states, one for each subsystem. This array
* is immutable after creation apart from the init_css_set
* during subsystem registration (at boot time).
*/
struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT];
}
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/cgroup.c')
-rw-r--r-- | kernel/cgroup.c | 35 |
1 files changed, 9 insertions, 26 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index c447c29..b893c8c 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2477,7 +2477,6 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry) static void __init cgroup_init_subsys(struct cgroup_subsys *ss) { struct cgroup_subsys_state *css; - struct list_head *l; printk(KERN_INFO "Initializing cgroup subsys %s\n", ss->name); @@ -2488,35 +2487,19 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss) BUG_ON(IS_ERR(css)); init_cgroup_css(css, ss, dummytop); - /* Update all cgroup groups to contain a subsys + /* Update the init_css_set to contain a subsys * pointer to this state - since the subsystem is - * newly registered, all tasks and hence all cgroup - * groups are in the subsystem's top cgroup. */ - write_lock(&css_set_lock); - l = &init_css_set.list; - do { - struct css_set *cg = - list_entry(l, struct css_set, list); - cg->subsys[ss->subsys_id] = dummytop->subsys[ss->subsys_id]; - l = l->next; - } while (l != &init_css_set.list); - write_unlock(&css_set_lock); - - /* If this subsystem requested that it be notified with fork - * events, we should send it one now for every process in the - * system */ - if (ss->fork) { - struct task_struct *g, *p; - - read_lock(&tasklist_lock); - do_each_thread(g, p) { - ss->fork(ss, p); - } while_each_thread(g, p); - read_unlock(&tasklist_lock); - } + * newly registered, all tasks and hence the + * init_css_set is in the subsystem's top cgroup. */ + init_css_set.subsys[ss->subsys_id] = dummytop->subsys[ss->subsys_id]; need_forkexit_callback |= ss->fork || ss->exit; + /* At system boot, before all subsystems have been + * registered, no tasks have been forked, so we don't + * need to invoke fork callbacks here. */ + BUG_ON(!list_empty(&init_task.tasks)); + ss->active = 1; } |