From: Li Zefan Now we can run through the hash table instead of running through the linked-list. Signed-off-by: Li Zefan Reviewed-by: Paul Menage Cc: Balbir Singh Cc: Pavel Emelyanov Cc: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton --- include/linux/cgroup.h | 6 ----- kernel/cgroup.c | 40 +++++++++++++++++++-------------------- 2 files changed, 20 insertions(+), 26 deletions(-) diff -puN include/linux/cgroup.h~cgroups-remove-the-css_set-linked-list include/linux/cgroup.h --- a/include/linux/cgroup.h~cgroups-remove-the-css_set-linked-list +++ a/include/linux/cgroup.h @@ -150,12 +150,6 @@ struct css_set { 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 -puN kernel/cgroup.c~cgroups-remove-the-css_set-linked-list kernel/cgroup.c --- a/kernel/cgroup.c~cgroups-remove-the-css_set-linked-list +++ a/kernel/cgroup.c @@ -242,7 +242,6 @@ static void unlink_css_set(struct css_se { 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_sys 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_sys /* 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_sys /* 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); @@ -2509,7 +2510,6 @@ 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); _