cgroup: use new hashtable implementation
Switch cgroup to use the new hashtable implementation. No functional changes.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 6643f70..54b3908 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -52,7 +52,7 @@
#include <linux/module.h>
#include <linux/delayacct.h>
#include <linux/cgroupstats.h>
-#include <linux/hash.h>
+#include <linux/hashtable.h>
#include <linux/namei.h>
#include <linux/pid_namespace.h>
#include <linux/idr.h>
@@ -376,22 +376,18 @@
* account cgroups in empty hierarchies.
*/
#define CSS_SET_HASH_BITS 7
-#define CSS_SET_TABLE_SIZE (1 << CSS_SET_HASH_BITS)
-static struct hlist_head css_set_table[CSS_SET_TABLE_SIZE];
+static DEFINE_HASHTABLE(css_set_table, CSS_SET_HASH_BITS);
-static struct hlist_head *css_set_hash(struct cgroup_subsys_state *css[])
+static unsigned long css_set_hash(struct cgroup_subsys_state *css[])
{
int i;
- int index;
- unsigned long tmp = 0UL;
+ unsigned long key = 0UL;
for (i = 0; i < CGROUP_SUBSYS_COUNT; i++)
- tmp += (unsigned long)css[i];
- tmp = (tmp >> 16) ^ tmp;
+ key += (unsigned long)css[i];
+ key = (key >> 16) ^ key;
- index = hash_long(tmp, CSS_SET_HASH_BITS);
-
- return &css_set_table[index];
+ return key;
}
/* We don't maintain the lists running through each css_set to its
@@ -418,7 +414,7 @@
}
/* This css_set is dead. unlink it and release cgroup refcounts */
- hlist_del(&cg->hlist);
+ hash_del(&cg->hlist);
css_set_count--;
list_for_each_entry_safe(link, saved_link, &cg->cg_links,
@@ -550,9 +546,9 @@
{
int i;
struct cgroupfs_root *root = cgrp->root;
- struct hlist_head *hhead;
struct hlist_node *node;
struct css_set *cg;
+ unsigned long key;
/*
* Build the set of subsystem state objects that we want to see in the
@@ -572,8 +568,8 @@
}
}
- hhead = css_set_hash(template);
- hlist_for_each_entry(cg, node, hhead, hlist) {
+ key = css_set_hash(template);
+ hash_for_each_possible(css_set_table, cg, node, hlist, key) {
if (!compare_css_sets(cg, oldcg, cgrp, template))
continue;
@@ -657,8 +653,8 @@
struct list_head tmp_cg_links;
- struct hlist_head *hhead;
struct cg_cgroup_link *link;
+ unsigned long key;
/* First see if we already have a cgroup group that matches
* the desired set */
@@ -704,8 +700,8 @@
css_set_count++;
/* Add this cgroup group to the hash table */
- hhead = css_set_hash(res->subsys);
- hlist_add_head(&res->hlist, hhead);
+ key = css_set_hash(res->subsys);
+ hash_add(css_set_table, &res->hlist, key);
write_unlock(&css_set_lock);
@@ -1597,6 +1593,8 @@
struct cgroupfs_root *existing_root;
const struct cred *cred;
int i;
+ struct hlist_node *node;
+ struct css_set *cg;
BUG_ON(sb->s_root != NULL);
@@ -1650,14 +1648,8 @@
/* Link the top cgroup in this hierarchy into all
* the css_set objects */
write_lock(&css_set_lock);
- 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;
-
- hlist_for_each_entry(cg, node, hhead, hlist)
- link_css_set(&tmp_cg_links, cg, root_cgrp);
- }
+ hash_for_each(css_set_table, i, node, cg, hlist)
+ link_css_set(&tmp_cg_links, cg, root_cgrp);
write_unlock(&css_set_lock);
free_cg_links(&tmp_cg_links);
@@ -4464,6 +4456,9 @@
{
struct cgroup_subsys_state *css;
int i, ret;
+ struct hlist_node *node, *tmp;
+ struct css_set *cg;
+ unsigned long key;
/* check name and function validity */
if (ss->name == NULL || strlen(ss->name) > MAX_CGROUP_TYPE_NAMELEN ||
@@ -4529,23 +4524,17 @@
* this is all done under the css_set_lock.
*/
write_lock(&css_set_lock);
- for (i = 0; i < CSS_SET_TABLE_SIZE; i++) {
- struct css_set *cg;
- struct hlist_node *node, *tmp;
- struct hlist_head *bucket = &css_set_table[i], *new_bucket;
-
- hlist_for_each_entry_safe(cg, node, tmp, bucket, hlist) {
- /* skip entries that we already rehashed */
- if (cg->subsys[ss->subsys_id])
- continue;
- /* remove existing entry */
- hlist_del(&cg->hlist);
- /* set new value */
- cg->subsys[ss->subsys_id] = css;
- /* recompute hash and restore entry */
- new_bucket = css_set_hash(cg->subsys);
- hlist_add_head(&cg->hlist, new_bucket);
- }
+ hash_for_each_safe(css_set_table, i, node, tmp, cg, hlist) {
+ /* skip entries that we already rehashed */
+ if (cg->subsys[ss->subsys_id])
+ continue;
+ /* remove existing entry */
+ hash_del(&cg->hlist);
+ /* set new value */
+ cg->subsys[ss->subsys_id] = css;
+ /* recompute hash and restore entry */
+ key = css_set_hash(cg->subsys);
+ hash_add(css_set_table, node, key);
}
write_unlock(&css_set_lock);
@@ -4577,7 +4566,6 @@
void cgroup_unload_subsys(struct cgroup_subsys *ss)
{
struct cg_cgroup_link *link;
- struct hlist_head *hhead;
BUG_ON(ss->module == NULL);
@@ -4611,11 +4599,12 @@
write_lock(&css_set_lock);
list_for_each_entry(link, &dummytop->css_sets, cgrp_link_list) {
struct css_set *cg = link->cg;
+ unsigned long key;
- hlist_del(&cg->hlist);
+ hash_del(&cg->hlist);
cg->subsys[ss->subsys_id] = NULL;
- hhead = css_set_hash(cg->subsys);
- hlist_add_head(&cg->hlist, hhead);
+ key = css_set_hash(cg->subsys);
+ hash_add(css_set_table, &cg->hlist, key);
}
write_unlock(&css_set_lock);
@@ -4657,9 +4646,6 @@
list_add(&init_css_set_link.cg_link_list,
&init_css_set.cg_links);
- for (i = 0; i < CSS_SET_TABLE_SIZE; i++)
- INIT_HLIST_HEAD(&css_set_table[i]);
-
for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
@@ -4693,7 +4679,7 @@
{
int err;
int i;
- struct hlist_head *hhead;
+ unsigned long key;
err = bdi_init(&cgroup_backing_dev_info);
if (err)
@@ -4712,8 +4698,8 @@
}
/* Add init_css_set to the hash table */
- hhead = css_set_hash(init_css_set.subsys);
- hlist_add_head(&init_css_set.hlist, hhead);
+ key = css_set_hash(init_css_set.subsys);
+ hash_add(css_set_table, &init_css_set.hlist, key);
BUG_ON(!init_root_id(&rootnode));
cgroup_kobj = kobject_create_and_add("cgroup", fs_kobj);
