Messages in this thread Patch in this message | | | Date | Thu, 11 Sep 2008 22:23:21 +0800 | From | Lai Jiangshan <> | Subject | [RFC PATCH -mm 1/2] cgroup: introduce hierarchy_id |
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every struct cgroupfs_root represent a hierarchy. and this patch introduces hierarchy_id for every hierarchy, just like pid for every struct task_struct.
hierarchy_id is very useful for fold struct cg_cgroup_link into struct css_set.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> --- diff --git a/kernel/cgroup.c b/kernel/cgroup.c index c8f9c70..4bd5560 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -84,6 +84,9 @@ struct cgroupfs_root { /* Tracks how many cgroups are currently defined in hierarchy.*/ int number_of_cgroups; + /* Unique id for every hierarchy. */ + int hierarchy_id; + /* A list running through the mounted hierarchies */ struct list_head root_list; @@ -191,6 +194,20 @@ void cgroup_huge_mem_free(void *ptr, cgroup_huge_mem_t *huge) kfree(ptr); } +static unsigned long hierarchy_id_bits; + +static int get_hierarchy_id(void) +{ + int id = find_first_zero_bit(&hierarchy_id_bits, CGROUP_SUBSYS_COUNT); + __set_bit(id, &hierarchy_id_bits); + return id; +} + +static void put_hierarchy_id(int id) +{ + __clear_bit(id, &hierarchy_id_bits); +} + /* * for_each_subsys() allows you to iterate on each subsystem attached to * an active hierarchy @@ -1080,6 +1097,7 @@ static int cgroup_get_sb(struct file_system_type *fs_type, BUG_ON(ret); list_add(&root->root_list, &roots); + root->hierarchy_id = get_hierarchy_id(); root_count++; sb->s_root->d_fsdata = &root->top_cgroup; @@ -1165,6 +1183,7 @@ static void cgroup_kill_sb(struct super_block *sb) { if (!list_empty(&root->root_list)) { list_del(&root->root_list); + put_hierarchy_id(root->hierarchy_id); root_count--; } mutex_unlock(&cgroup_mutex); @@ -2627,6 +2646,7 @@ int __init cgroup_init_early(void) css_set_count = 1; init_cgroup_root(&rootnode); list_add(&rootnode.root_list, &roots); + rootnode.hierarchy_id = get_hierarchy_id(); root_count = 1; init_task.cgroups = &init_css_set;
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