cgroups: remove the css_set linked-list

Now we can run through the hash table instead of running through the
linked-list.

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>

1 files changed, 20 insertions, 20 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index b893c8c9485..aeceb886898 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -242,7 +242,6 @@ static void unlink_css_set(struct css_set *cg)
 {
         write_lock(&css_set_lock);
         hlist_del(&cg->hlist);
-        list_del(&cg->list);
         css_set_count--;
         while (!list_empty(&cg->cg_links)) {
                 struct cg_cgroup_link *link;
@@ -477,8 +476,6 @@ static struct css_set *find_css_set(
 
         BUG_ON(!list_empty(&tmp_cg_links));
 
-        /* Link this cgroup group into the list */
-        list_add(&res->list, &init_css_set.list);
         css_set_count++;
 
         /* Add this cgroup group to the hash table */
@@ -963,7 +960,7 @@ static int cgroup_get_sb(struct file_system_type *fs_type,
         int ret = 0;
         struct super_block *sb;
         struct cgroupfs_root *root;
-        struct list_head tmp_cg_links, *l;
+        struct list_head tmp_cg_links;
         INIT_LIST_HEAD(&tmp_cg_links);
 
         /* First find the desired set of subsystems */
@@ -1005,6 +1002,7 @@ static int cgroup_get_sb(struct file_system_type *fs_type,
                 /* New superblock */
                 struct cgroup *cgrp = &root->top_cgroup;
                 struct inode *inode;
+                int i;
 
                 BUG_ON(sb->s_root != NULL);
 
@@ -1049,22 +1047,25 @@ static int cgroup_get_sb(struct file_system_type *fs_type,
                 /* Link the top cgroup in this hierarchy into all
                  * the css_set objects */
                 write_lock(&css_set_lock);
-                l = &init_css_set.list;
-                do {
+                for (i = 0; i < CSS_SET_TABLE_SIZE; i++) {
+                        struct hlist_head *hhead = &css_set_table[i];
+                        struct hlist_node *node;
                         struct css_set *cg;
-                        struct cg_cgroup_link *link;
-                        cg = list_entry(l, struct css_set, list);
-                        BUG_ON(list_empty(&tmp_cg_links));
-                        link = list_entry(tmp_cg_links.next,
-                                          struct cg_cgroup_link,
-                                          cgrp_link_list);
-                        list_del(&link->cgrp_link_list);
-                        link->cg = cg;
-                        list_add(&link->cgrp_link_list,
-                                 &root->top_cgroup.css_sets);
-                        list_add(&link->cg_link_list, &cg->cg_links);
-                        l = l->next;
-                } while (l != &init_css_set.list);
+
+                        hlist_for_each_entry(cg, node, hhead, hlist) {
+                                struct cg_cgroup_link *link;
+
+                                BUG_ON(list_empty(&tmp_cg_links));
+                                link = list_entry(tmp_cg_links.next,
+                                                  struct cg_cgroup_link,
+                                                  cgrp_link_list);
+                                list_del(&link->cgrp_link_list);
+                                link->cg = cg;
+                                list_add(&link->cgrp_link_list,
+                                         &root->top_cgroup.css_sets);
+                                list_add(&link->cg_link_list, &cg->cg_links);
+                        }
+                }
                 write_unlock(&css_set_lock);
 
                 free_cg_links(&tmp_cg_links);
@@ -2514,7 +2515,6 @@ int __init cgroup_init_early(void)
         int i;
         kref_init(&init_css_set.ref);
         kref_get(&init_css_set.ref);
-        INIT_LIST_HEAD(&init_css_set.list);
         INIT_LIST_HEAD(&init_css_set.cg_links);
         INIT_LIST_HEAD(&init_css_set.tasks);
         INIT_HLIST_NODE(&init_css_set.hlist);