[Devel] [PATCH VZ8 v1 10/14] ve/cgroup: private per-cgroup-root data container

[Kirill Tkhai]

On 20.01.2021 12:56, Valeriy Vdovin wrote:
> As long as each ve is internally attached to a particular
> css_set via it's init_task, it's good to have container with parameters,
> which are common to each cgroup subsystem hierarchy, rooting from it's
> virtual root.
> 
> (Cherry-picked from 4a98f07102fd248ad4218a07b5ec5ec90da10288)
> Signed-off-by: Valeriy Vdovin <valeriy.vdovin at virtuozzo.com>

Reviewed-by: Kirill Tkhai <ktkhai at virtuozzo.com>

> ---
>  include/linux/ve.h |  7 +++++
>  kernel/ve/ve.c     | 75 ++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 82 insertions(+)
> 
> diff --git a/include/linux/ve.h b/include/linux/ve.h
> index 2ab39b607708..44369dddeb24 100644
> --- a/include/linux/ve.h
> +++ b/include/linux/ve.h
> @@ -114,6 +114,13 @@ struct ve_struct {
>  
>  	struct workqueue_struct	*wq;
>  	struct work_struct	release_agent_work;
> +
> +	/*
> +	 * List of data, private for each root cgroup in
> +	 * ve's css_set.
> +	 */
> +	struct list_head	per_cgroot_list;
> +	spinlock_t		per_cgroot_list_lock;
>  };
>  
>  struct ve_devmnt {
> diff --git a/kernel/ve/ve.c b/kernel/ve/ve.c
> index 008e372756f9..738f8b6465d4 100644
> --- a/kernel/ve/ve.c
> +++ b/kernel/ve/ve.c
> @@ -30,6 +30,14 @@
>  
>  #include "../cgroup/cgroup-internal.h" /* For cgroup_task_count() */
>  
> +struct per_cgroot_data {
> +	struct list_head list;
> +	/*
> +	 * data is related to this cgroup
> +	 */
> +	struct cgroup *cgroot;
> +};
> +
>  extern struct kmapset_set sysfs_ve_perms_set;
>  
>  static struct kmem_cache *ve_cachep;
> @@ -67,6 +75,9 @@ struct ve_struct ve0 = {
>  	.release_list		= LIST_HEAD_INIT(ve0.release_list),
>  	.release_agent_work	= __WORK_INITIALIZER(ve0.release_agent_work,
>  					cgroup1_release_agent),
> +	.per_cgroot_list	= LIST_HEAD_INIT(ve0.per_cgroot_list),
> +	.per_cgroot_list_lock	= __SPIN_LOCK_UNLOCKED(
> +					ve0.per_cgroot_list_lock),
>  };
>  EXPORT_SYMBOL(ve0);
>  
> @@ -199,6 +210,53 @@ int nr_threads_ve(struct ve_struct *ve)
>  }
>  EXPORT_SYMBOL(nr_threads_ve);
>  
> +static struct per_cgroot_data *per_cgroot_data_find_locked(
> +	struct list_head *per_cgroot_list, struct cgroup *cgroot)
> +{
> +	struct per_cgroot_data *data;
> +
> +	list_for_each_entry(data, per_cgroot_list, list) {
> +		if (data->cgroot == cgroot)
> +			return data;
> +	}
> +	return NULL;
> +}
> +
> +static inline struct per_cgroot_data *per_cgroot_get_or_create(
> +	struct ve_struct *ve, struct cgroup *cgroot)
> +{
> +	struct per_cgroot_data *data, *other_data;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&ve->per_cgroot_list_lock, flags);
> +	data = per_cgroot_data_find_locked(&ve->per_cgroot_list,
> +		cgroot);
> +	spin_unlock_irqrestore(&ve->per_cgroot_list_lock, flags);
> +
> +	if (data)
> +		return data;
> +
> +	data = kzalloc(sizeof(struct per_cgroot_data), GFP_KERNEL);
> +	if (!data)
> +		return ERR_PTR(-ENOMEM);
> +
> +	spin_lock_irqsave(&ve->per_cgroot_list_lock, flags);
> +	other_data = per_cgroot_data_find_locked(&ve->per_cgroot_list,
> +		cgroot);
> +
> +	if (other_data) {
> +		spin_unlock_irqrestore(&ve->per_cgroot_list_lock, flags);
> +		kfree(data);
> +		return other_data;
> +	}
> +
> +	data->cgroot = cgroot;
> +	list_add(&data->list, &ve->per_cgroot_list);
> +
> +	spin_unlock_irqrestore(&ve->per_cgroot_list_lock, flags);
> +	return data;
> +}
> +
>  struct cgroup_subsys_state *ve_get_init_css(struct ve_struct *ve, int subsys_id)
>  {
>  	struct cgroup_subsys_state *css;
> @@ -533,6 +591,19 @@ static int ve_start_container(struct ve_struct *ve)
>  	return err;
>  }
>  
> +static void ve_per_cgroot_free(struct ve_struct *ve)
> +{
> +	struct per_cgroot_data *data, *saved;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&ve->per_cgroot_list_lock, flags);
> +	list_for_each_entry_safe(data, saved, &ve->per_cgroot_list, list) {
> +		list_del_init(&data->list);
> +		kfree(data);
> +	}
> +	spin_unlock_irqrestore(&ve->per_cgroot_list_lock, flags);
> +}
> +
>  void ve_stop_ns(struct pid_namespace *pid_ns)
>  {
>  	struct ve_struct *ve = current->task_ve;
> @@ -589,6 +660,8 @@ void ve_exit_ns(struct pid_namespace *pid_ns)
>  
>  	ve_workqueue_stop(ve);
>  
> +	ve_per_cgroot_free(ve);
> +
>  	/*
>  	 * At this point all userspace tasks in container are dead.
>  	 */
> @@ -699,6 +772,7 @@ static struct cgroup_subsys_state *ve_create(struct cgroup_subsys_state *parent_
>  
>  	INIT_WORK(&ve->release_agent_work, cgroup1_release_agent);
>  	spin_lock_init(&ve->release_list_lock);
> +	spin_lock_init(&ve->per_cgroot_list_lock);
>  
>  	ve->_randomize_va_space = ve0._randomize_va_space;
>  
> @@ -721,6 +795,7 @@ static struct cgroup_subsys_state *ve_create(struct cgroup_subsys_state *parent_
>  #endif
>  	INIT_LIST_HEAD(&ve->devmnt_list);
>  	INIT_LIST_HEAD(&ve->release_list);
> +	INIT_LIST_HEAD(&ve->per_cgroot_list);
>  	mutex_init(&ve->devmnt_mutex);
>  
>  #ifdef CONFIG_AIO
>