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[bpf-next,v3,11/13] mm, memcg: Add new helper task_under_memcg_hierarchy

Message ID 20220902023003.47124-12-laoar.shao@gmail.com (mailing list archive)
State New
Headers show
Series bpf: Introduce selectable memcg for bpf map | expand

Commit Message

Yafang Shao Sept. 2, 2022, 2:30 a.m. UTC 
Introduce a new helper to check if a task belongs to a specific memcg.
It is similar to mm_match_cgroup() except that the new helper is checked
against a task rather than a mm struct. So with this new helper we can
check a task directly.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
---
 include/linux/memcontrol.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
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Patch

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 7a7f252..3b8a8dd 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -887,6 +887,20 @@  static inline bool mem_cgroup_is_descendant(struct mem_cgroup *memcg,
 	return cgroup_is_descendant(memcg->css.cgroup, root->css.cgroup);
 }
 
+static inline bool task_under_memcg_hierarchy(struct task_struct *p,
+					      struct mem_cgroup *memcg)
+{
+	struct mem_cgroup *task_memcg;
+	bool match = false;
+
+	rcu_read_lock();
+	task_memcg = mem_cgroup_from_task(p);
+	if (task_memcg)
+		match = mem_cgroup_is_descendant(task_memcg, memcg);
+	rcu_read_unlock();
+	return match;
+}
+
 static inline bool mm_match_cgroup(struct mm_struct *mm,
 				   struct mem_cgroup *memcg)
 {