diff mbox

[2/9] cgroup: Use rculist ops for cgroup->children

Message ID 1351931915-1701-3-git-send-email-tj@kernel.org (mailing list archive)
State Not Applicable, archived
Headers show

Commit Message

Tejun Heo Nov. 3, 2012, 8:38 a.m. UTC
Use RCU safe list operations for cgroup->children.  This will be used
to implement cgroup children / descendant walking which can be used by
controllers.

Note that cgroup_create() now puts a new cgroup at the end of the
->children list instead of head.  This isn't strictly necessary but is
done so that the iteration order is more conventional.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
 include/linux/cgroup.h | 1 +
 kernel/cgroup.c        | 8 +++-----
 2 files changed, 4 insertions(+), 5 deletions(-)

Comments

Michal Hocko Nov. 7, 2012, 3:30 p.m. UTC | #1
On Sat 03-11-12 01:38:28, Tejun Heo wrote:
> Use RCU safe list operations for cgroup->children.  This will be used
> to implement cgroup children / descendant walking which can be used by
> controllers.
> 
> Note that cgroup_create() now puts a new cgroup at the end of the
> ->children list instead of head.  This isn't strictly necessary but is
> done so that the iteration order is more conventional.
> 
> Signed-off-by: Tejun Heo <tj@kernel.org>

Reviewed-by: Michal Hocko <mhocko@suse.cz>

> ---
>  include/linux/cgroup.h | 1 +
>  kernel/cgroup.c        | 8 +++-----
>  2 files changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
> index b442122..90c33eb 100644
> --- a/include/linux/cgroup.h
> +++ b/include/linux/cgroup.h
> @@ -12,6 +12,7 @@
>  #include <linux/cpumask.h>
>  #include <linux/nodemask.h>
>  #include <linux/rcupdate.h>
> +#include <linux/rculist.h>
>  #include <linux/cgroupstats.h>
>  #include <linux/prio_heap.h>
>  #include <linux/rwsem.h>
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index f05d992..cc5d2a0 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -1650,7 +1650,6 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
>  
>  		free_cg_links(&tmp_cg_links);
>  
> -		BUG_ON(!list_empty(&root_cgrp->sibling));
>  		BUG_ON(!list_empty(&root_cgrp->children));
>  		BUG_ON(root->number_of_cgroups != 1);
>  
> @@ -1699,7 +1698,6 @@ static void cgroup_kill_sb(struct super_block *sb) {
>  
>  	BUG_ON(root->number_of_cgroups != 1);
>  	BUG_ON(!list_empty(&cgrp->children));
> -	BUG_ON(!list_empty(&cgrp->sibling));
>  
>  	mutex_lock(&cgroup_mutex);
>  	mutex_lock(&cgroup_root_mutex);
> @@ -4053,7 +4051,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
>  		}
>  	}
>  
> -	list_add(&cgrp->sibling, &cgrp->parent->children);
> +	list_add_tail_rcu(&cgrp->sibling, &cgrp->parent->children);
>  	root->number_of_cgroups++;
>  
>  	err = cgroup_create_dir(cgrp, dentry, mode);
> @@ -4084,7 +4082,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
>  
>   err_remove:
>  
> -	list_del(&cgrp->sibling);
> +	list_del_rcu(&cgrp->sibling);
>  	root->number_of_cgroups--;
>  
>   err_destroy:
> @@ -4210,7 +4208,7 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
>  	raw_spin_unlock(&release_list_lock);
>  
>  	/* delete this cgroup from parent->children */
> -	list_del_init(&cgrp->sibling);
> +	list_del_rcu(&cgrp->sibling);
>  
>  	list_del_init(&cgrp->allcg_node);
>  
> -- 
> 1.7.11.7
>
KAMEZAWA Hiroyuki Nov. 8, 2012, 3:01 a.m. UTC | #2
(2012/11/03 17:38), Tejun Heo wrote:
> Use RCU safe list operations for cgroup->children.  This will be used
> to implement cgroup children / descendant walking which can be used by
> controllers.
>
> Note that cgroup_create() now puts a new cgroup at the end of the
> ->children list instead of head.  This isn't strictly necessary but is
> done so that the iteration order is more conventional.
>
> Signed-off-by: Tejun Heo <tj@kernel.org>

Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>


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Zefan Li Nov. 9, 2012, 9:10 a.m. UTC | #3
On 2012/11/3 16:38, Tejun Heo wrote:
> Use RCU safe list operations for cgroup->children.  This will be used
> to implement cgroup children / descendant walking which can be used by
> controllers.
> 
> Note that cgroup_create() now puts a new cgroup at the end of the
> ->children list instead of head.  This isn't strictly necessary but is
> done so that the iteration order is more conventional.
> 
> Signed-off-by: Tejun Heo <tj@kernel.org>

Acked-by: Li Zefan <lizefan@huawei.com>

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diff mbox

Patch

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index b442122..90c33eb 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -12,6 +12,7 @@ 
 #include <linux/cpumask.h>
 #include <linux/nodemask.h>
 #include <linux/rcupdate.h>
+#include <linux/rculist.h>
 #include <linux/cgroupstats.h>
 #include <linux/prio_heap.h>
 #include <linux/rwsem.h>
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index f05d992..cc5d2a0 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1650,7 +1650,6 @@  static struct dentry *cgroup_mount(struct file_system_type *fs_type,
 
 		free_cg_links(&tmp_cg_links);
 
-		BUG_ON(!list_empty(&root_cgrp->sibling));
 		BUG_ON(!list_empty(&root_cgrp->children));
 		BUG_ON(root->number_of_cgroups != 1);
 
@@ -1699,7 +1698,6 @@  static void cgroup_kill_sb(struct super_block *sb) {
 
 	BUG_ON(root->number_of_cgroups != 1);
 	BUG_ON(!list_empty(&cgrp->children));
-	BUG_ON(!list_empty(&cgrp->sibling));
 
 	mutex_lock(&cgroup_mutex);
 	mutex_lock(&cgroup_root_mutex);
@@ -4053,7 +4051,7 @@  static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
 		}
 	}
 
-	list_add(&cgrp->sibling, &cgrp->parent->children);
+	list_add_tail_rcu(&cgrp->sibling, &cgrp->parent->children);
 	root->number_of_cgroups++;
 
 	err = cgroup_create_dir(cgrp, dentry, mode);
@@ -4084,7 +4082,7 @@  static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
 
  err_remove:
 
-	list_del(&cgrp->sibling);
+	list_del_rcu(&cgrp->sibling);
 	root->number_of_cgroups--;
 
  err_destroy:
@@ -4210,7 +4208,7 @@  static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
 	raw_spin_unlock(&release_list_lock);
 
 	/* delete this cgroup from parent->children */
-	list_del_init(&cgrp->sibling);
+	list_del_rcu(&cgrp->sibling);
 
 	list_del_init(&cgrp->allcg_node);