Commit 0ac801fe authored by Li Zefan's avatar Li Zefan Committed by Tejun Heo
Browse files

cgroup: use new hashtable implementation 



Switch cgroup to use the new hashtable implementation. No functional changes.

Signed-off-by: default avatarLi Zefan <lizefan@huawei.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 799105d5

kernel/cgroup.c

+39 −53
Original line number Diff line number Diff line
@@ -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 @@ static int css_set_count; 
 * 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 @@ static void __put_css_set(struct css_set *cg, int taskexit) 
	}



	/* 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 @@ static struct css_set *find_existing_css_set( 
{

	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 @@ static struct css_set *find_existing_css_set( 
		}

	}



	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 @@ static struct css_set *find_css_set( 


	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 @@ static struct css_set *find_css_set( 
	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 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, 
		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 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, 
		/* 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)

		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 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) 
{

	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 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) 
	 * 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) {

	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 */

			hlist_del(&cg->hlist);

		hash_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);

		}

		key = css_set_hash(cg->subsys);

		hash_add(css_set_table, node, key);

	}

	write_unlock(&css_set_lock);
@@ -4577,7 +4566,6 @@ EXPORT_SYMBOL_GPL(cgroup_load_subsys); 
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 @@ void cgroup_unload_subsys(struct cgroup_subsys *ss) 
	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 @@ int __init cgroup_init_early(void) 
	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 __init cgroup_init(void) 
{

	int err;

	int i;

	struct hlist_head *hhead;

	unsigned long key;



	err = bdi_init(&cgroup_backing_dev_info);

	if (err)
@@ -4712,8 +4698,8 @@ int __init cgroup_init(void) 
	}



	/* 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);