cgroup: convert cgroup_has_live_children() into css_has_online_children() (f3d46500) · Commits · 戴 / test

include/linux/cgroup.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -873,6 +873,8 @@ css_next_descendant_post(struct cgroup_subsys_state *pos,
		for ((pos) = css_next_descendant_post(NULL, (css)); (pos); \
		(pos) = css_next_descendant_post((pos), (css)))

		bool css_has_online_children(struct cgroup_subsys_state *css);

		/* A css_task_iter should be treated as an opaque object */
		struct css_task_iter {
		struct cgroup_subsys *ss;

kernel/cgroup.c

+20 −12

Original line number	Diff line number	Diff line
		@@ -175,7 +175,6 @@ static int need_forkexit_callback __read_mostly;
		static struct cftype cgroup_base_files[];

		static void cgroup_put(struct cgroup *cgrp);
		static bool cgroup_has_live_children(struct cgroup *cgrp);
		static int rebind_subsystems(struct cgroup_root *dst_root,
		unsigned int ss_mask);
		static int cgroup_destroy_locked(struct cgroup *cgrp);
		@@ -1769,7 +1768,7 @@ static void cgroup_kill_sb(struct super_block *sb)
		* This prevents new mounts by disabling percpu_ref_tryget_live().
		* cgroup_mount() may wait for @root's release.
		*/
		if (cgroup_has_live_children(&root->cgrp))
		if (css_has_online_children(&root->cgrp.self))
		cgroup_put(&root->cgrp);
		else
		percpu_ref_kill(&root->cgrp.self.refcnt);
		@@ -3291,19 +3290,28 @@ css_next_descendant_post(struct cgroup_subsys_state *pos,
		return pos->parent;
		}

		static bool cgroup_has_live_children(struct cgroup *cgrp)
		/**
		* css_has_online_children - does a css have online children
		* @css: the target css
		*
		* Returns %true if @css has any online children; otherwise, %false. This
		* function can be called from any context but the caller is responsible
		* for synchronizing against on/offlining as necessary.
		*/
		bool css_has_online_children(struct cgroup_subsys_state *css)
		{
		struct cgroup *child;
		struct cgroup_subsys_state *child;
		bool ret = false;

		rcu_read_lock();
		list_for_each_entry_rcu(child, &cgrp->self.children, self.sibling) {
		if (!cgroup_is_dead(child)) {
		rcu_read_unlock();
		return true;
		css_for_each_child(child, css) {
		if (css->flags & CSS_ONLINE) {
		ret = true;
		break;
		}
		}
		rcu_read_unlock();
		return false;
		return ret;
		}

		/**
		@@ -4535,7 +4543,7 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
		* ->self.children as dead children linger on it while being
		* drained; otherwise, "rmdir parent/child parent" may fail.
		*/
		if (cgroup_has_live_children(cgrp))
		if (css_has_online_children(&cgrp->self))
		return -EBUSY;

		/*
		@@ -5014,8 +5022,8 @@ void cgroup_exit(struct task_struct *tsk)

		static void check_for_release(struct cgroup *cgrp)
		{
		if (cgroup_is_releasable(cgrp) &&
		list_empty(&cgrp->cset_links) && !cgroup_has_live_children(cgrp)) {
		if (cgroup_is_releasable(cgrp) && list_empty(&cgrp->cset_links) &&
		!css_has_online_children(&cgrp->self)) {
		/*
		* Control Group is currently removeable. If it's not
		* already queued for a userspace notification, queue

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