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

[Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>]

oom_unkillable_task() no longer calls task_in_mem_cgroup().

Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
---
 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