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>

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index f585b7cde87b32191351204caaa3a4352e942a6c..d58a958444abb49f79dcc02dea2486ffc050ebba 100644 (file)
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -149,12 +149,6 @@ struct css_set {
        /* Reference count */
        struct kref ref;
 
-       /*
-        * List running through all cgroup groups. Protected by
-        * css_set_lock
-        */
-       struct list_head list;
-
        /*
         * List running through all cgroup groups in the same hash
         * slot. Protected by css_set_lock

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index b893c8c94858bb203fe2fda7d2f44e9e8b4a5ca4..aeceb88689817482ceadbd51a233d294de5c5a35 100644 (file)
--- 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);