cgroup: use a per-cgroup work for release agent (971ff493) · Commits · 戴 / test

include/linux/cgroup.h

+3 −7

Original line number	Diff line number	Diff line
		@@ -233,13 +233,6 @@ struct cgroup {
		*/
		struct list_head e_csets[CGROUP_SUBSYS_COUNT];

		/*
		* Linked list running through all cgroups that can
		* potentially be reaped by the release agent. Protected by
		* release_list_lock
		*/
		struct list_head release_list;

		/*
		* list of pidlists, up to two for each namespace (one for procs, one
		* for tasks); created on demand.
		@@ -249,6 +242,9 @@ struct cgroup {

		/* used to wait for offlining of csses */
		wait_queue_head_t offline_waitq;

		/* used to schedule release agent */
		struct work_struct release_agent_work;
		};

		#define MAX_CGROUP_ROOT_NAMELEN 64

kernel/cgroup.c

+33 −75

Original line number	Diff line number	Diff line
		@@ -392,12 +392,7 @@ static int notify_on_release(const struct cgroup *cgrp)
		; \
		else

		/* the list of cgroups eligible for automatic release. Protected by
		* release_list_lock */
		static LIST_HEAD(release_list);
		static DEFINE_RAW_SPINLOCK(release_list_lock);
		static void cgroup_release_agent(struct work_struct *work);
		static DECLARE_WORK(release_agent_work, cgroup_release_agent);
		static void check_for_release(struct cgroup *cgrp);

		/*
		@@ -1577,7 +1572,6 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp)
		INIT_LIST_HEAD(&cgrp->self.sibling);
		INIT_LIST_HEAD(&cgrp->self.children);
		INIT_LIST_HEAD(&cgrp->cset_links);
		INIT_LIST_HEAD(&cgrp->release_list);
		INIT_LIST_HEAD(&cgrp->pidlists);
		mutex_init(&cgrp->pidlist_mutex);
		cgrp->self.cgroup = cgrp;
		@@ -1587,6 +1581,7 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp)
		INIT_LIST_HEAD(&cgrp->e_csets[ssid]);

		init_waitqueue_head(&cgrp->offline_waitq);
		INIT_WORK(&cgrp->release_agent_work, cgroup_release_agent);
		}

		static void init_cgroup_root(struct cgroup_root *root,
		@@ -4342,6 +4337,7 @@ static void css_free_work_fn(struct work_struct *work)
		/* cgroup free path */
		atomic_dec(&cgrp->root->nr_cgrps);
		cgroup_pidlist_destroy_all(cgrp);
		cancel_work_sync(&cgrp->release_agent_work);

		if (cgroup_parent(cgrp)) {
		/*
		@@ -4804,12 +4800,6 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
		for_each_css(css, ssid, cgrp)
		kill_css(css);

		/* CSS_ONLINE is clear, remove from ->release_list for the last time */
		raw_spin_lock(&release_list_lock);
		if (!list_empty(&cgrp->release_list))
		list_del_init(&cgrp->release_list);
		raw_spin_unlock(&release_list_lock);

		/*
		* Remove @cgrp directory along with the base files. @cgrp has an
		* extra ref on its kn.
		@@ -5271,25 +5261,9 @@ 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) &&
		!css_has_online_children(&cgrp->self)) {
		/*
		* Control Group is currently removeable. If it's not
		* already queued for a userspace notification, queue
		* it now
		*/
		int need_schedule_work = 0;

		raw_spin_lock(&release_list_lock);
		if (!cgroup_is_dead(cgrp) &&
		list_empty(&cgrp->release_list)) {
		list_add(&cgrp->release_list, &release_list);
		need_schedule_work = 1;
		}
		raw_spin_unlock(&release_list_lock);
		if (need_schedule_work)
		schedule_work(&release_agent_work);
		}
		if (cgroup_is_releasable(cgrp) && !cgroup_has_tasks(cgrp) &&
		!css_has_online_children(&cgrp->self) && !cgroup_is_dead(cgrp))
		schedule_work(&cgrp->release_agent_work);
		}

		/*
		@@ -5317,52 +5291,36 @@ static void check_for_release(struct cgroup *cgrp)
		*/
		static void cgroup_release_agent(struct work_struct *work)
		{
		BUG_ON(work != &release_agent_work);
		mutex_lock(&cgroup_mutex);
		raw_spin_lock(&release_list_lock);
		while (!list_empty(&release_list)) {
		char argv[3], envp[3];
		int i;
		struct cgroup *cgrp =
		container_of(work, struct cgroup, release_agent_work);
		char pathbuf = NULL, agentbuf = NULL, *path;
		struct cgroup *cgrp = list_entry(release_list.next,
		struct cgroup,
		release_list);
		list_del_init(&cgrp->release_list);
		raw_spin_unlock(&release_list_lock);
		char argv[3], envp[3];

		mutex_lock(&cgroup_mutex);

		pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
		if (!pathbuf)
		goto continue_free;
		agentbuf = kstrdup(cgrp->root->release_agent_path, GFP_KERNEL);
		if (!pathbuf \|\| !agentbuf)
		goto out;

		path = cgroup_path(cgrp, pathbuf, PATH_MAX);
		if (!path)
		goto continue_free;
		agentbuf = kstrdup(cgrp->root->release_agent_path, GFP_KERNEL);
		if (!agentbuf)
		goto continue_free;
		goto out;

		i = 0;
		argv[i++] = agentbuf;
		argv[i++] = path;
		argv[i] = NULL;
		argv[0] = agentbuf;
		argv[1] = path;
		argv[2] = NULL;

		i = 0;
		/* minimal command environment */
		envp[i++] = "HOME=/";
		envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
		envp[i] = NULL;
		envp[0] = "HOME=/";
		envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
		envp[2] = NULL;

		/* Drop the lock while we invoke the usermode helper,
		* since the exec could involve hitting disk and hence
		* be a slow process */
		mutex_unlock(&cgroup_mutex);
		call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
		mutex_lock(&cgroup_mutex);
		continue_free:
		kfree(pathbuf);
		out:
		kfree(agentbuf);
		raw_spin_lock(&release_list_lock);
		}
		raw_spin_unlock(&release_list_lock);
		mutex_unlock(&cgroup_mutex);
		kfree(pathbuf);
		}

		static int __init cgroup_disable(char *str)

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