Re: [PATCH] mm: memcontrol: Remove task_in_mem_cgroup().

[Michal Hocko <mhocko@kernel.org>]

On Tue 18-06-19 19:02:34, Tetsuo Handa wrote:
> oom_unkillable_task() no longer calls task_in_mem_cgroup().

This was indeed the last caller of this function which got me surprised.
Let's fold this into the refactoring patch.

Thanks!

> 
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Cc: Shakeel Butt <shakeelb@google.com>
> Cc: David Rientjes <rientjes@google.com>
> ---
>  include/linux/memcontrol.h |  7 -------
>  mm/memcontrol.c            | 26 --------------------------
>  2 files changed, 33 deletions(-)
> 
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 1dcb763..dcc5785 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -392,7 +392,6 @@ static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,
>  
>  struct lruvec *mem_cgroup_page_lruvec(struct page *, struct pglist_data *);
>  
> -bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg);
>  struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
>  
>  struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm);
> @@ -870,12 +869,6 @@ static inline bool mm_match_cgroup(struct mm_struct *mm,
>  	return true;
>  }
>  
> -static inline bool task_in_mem_cgroup(struct task_struct *task,
> -				      const struct mem_cgroup *memcg)
> -{
> -	return true;
> -}
> -
>  static inline struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
>  {
>  	return NULL;
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index b09ff45..0b17c77 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1255,32 +1255,6 @@ void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
>  		*lru_size += nr_pages;
>  }
>  
> -bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg)
> -{
> -	struct mem_cgroup *task_memcg;
> -	struct task_struct *p;
> -	bool ret;
> -
> -	p = find_lock_task_mm(task);
> -	if (p) {
> -		task_memcg = get_mem_cgroup_from_mm(p->mm);
> -		task_unlock(p);
> -	} else {
> -		/*
> -		 * All threads may have already detached their mm's, but the oom
> -		 * killer still needs to detect if they have already been oom
> -		 * killed to prevent needlessly killing additional tasks.
> -		 */
> -		rcu_read_lock();
> -		task_memcg = mem_cgroup_from_task(task);
> -		css_get(&task_memcg->css);
> -		rcu_read_unlock();
> -	}
> -	ret = mem_cgroup_is_descendant(task_memcg, memcg);
> -	css_put(&task_memcg->css);
> -	return ret;
> -}
> -
>  /**
>   * mem_cgroup_margin - calculate chargeable space of a memory cgroup
>   * @memcg: the memory cgroup
> -- 
> 1.8.3.1

-- 
Michal Hocko
SUSE Labs