X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=kernel%2Fworkqueue.c;h=ddee541ea97aa63863ebcdbee26c437de6b63e42;hb=782492a7a4807317319a0b1832594d07ba79747d;hp=fc5d23d752a574d3c03487c8c817352a5972f83c;hpb=3a7d2f4f4427f4b241f8240e370099e2ec1fd307;p=linux-2.6-block.git

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index fc5d23d752a5..ddee541ea97a 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -259,6 +259,8 @@ struct workqueue_struct {
 	struct wq_device	*wq_dev;	/* I: for sysfs interface */
 #endif
 #ifdef CONFIG_LOCKDEP
+	char			*lock_name;
+	struct lock_class_key	key;
 	struct lockdep_map	lockdep_map;
 #endif
 	char			name[WQ_NAME_LEN]; /* I: workqueue name */
@@ -646,7 +648,7 @@ static void set_work_pool_and_clear_pending(struct work_struct *work,
 	 * The following mb guarantees that previous clear of a PENDING bit
 	 * will not be reordered with any speculative LOADS or STORES from
 	 * work->current_func, which is executed afterwards.  This possible
-	 * reordering can lead to a missed execution on attempt to qeueue
+	 * reordering can lead to a missed execution on attempt to queue
 	 * the same @work.  E.g. consider this case:
 	 *
 	 *   CPU#0                         CPU#1
@@ -918,6 +920,16 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task)
  * CONTEXT:
  * spin_lock_irq(rq->lock)
  *
+ * This function is called during schedule() when a kworker is going
+ * to sleep. It's used by psi to identify aggregation workers during
+ * dequeuing, to allow periodic aggregation to shut-off when that
+ * worker is the last task in the system or cgroup to go to sleep.
+ *
+ * As this function doesn't involve any workqueue-related locking, it
+ * only returns stable values when called from inside the scheduler's
+ * queuing and dequeuing paths, when @task, which must be a kworker,
+ * is guaranteed to not be processing any works.
+ *
  * Return:
  * The last work function %current executed as a worker, NULL if it
  * hasn't executed any work yet.
@@ -1341,7 +1353,7 @@ static bool is_chained_work(struct workqueue_struct *wq)
 
 	worker = current_wq_worker();
 	/*
-	 * Return %true iff I'm a worker execuing a work item on @wq.  If
+	 * Return %true iff I'm a worker executing a work item on @wq.  If
 	 * I'm @worker, it's safe to dereference it without locking.
 	 */
 	return worker && worker->current_pwq->wq == wq;
@@ -1512,6 +1524,90 @@ bool queue_work_on(int cpu, struct workqueue_struct *wq,
 }
 EXPORT_SYMBOL(queue_work_on);
 
+/**
+ * workqueue_select_cpu_near - Select a CPU based on NUMA node
+ * @node: NUMA node ID that we want to select a CPU from
+ *
+ * This function will attempt to find a "random" cpu available on a given
+ * node. If there are no CPUs available on the given node it will return
+ * WORK_CPU_UNBOUND indicating that we should just schedule to any
+ * available CPU if we need to schedule this work.
+ */
+static int workqueue_select_cpu_near(int node)
+{
+	int cpu;
+
+	/* No point in doing this if NUMA isn't enabled for workqueues */
+	if (!wq_numa_enabled)
+		return WORK_CPU_UNBOUND;
+
+	/* Delay binding to CPU if node is not valid or online */
+	if (node < 0 || node >= MAX_NUMNODES || !node_online(node))
+		return WORK_CPU_UNBOUND;
+
+	/* Use local node/cpu if we are already there */
+	cpu = raw_smp_processor_id();
+	if (node == cpu_to_node(cpu))
+		return cpu;
+
+	/* Use "random" otherwise know as "first" online CPU of node */
+	cpu = cpumask_any_and(cpumask_of_node(node), cpu_online_mask);
+
+	/* If CPU is valid return that, otherwise just defer */
+	return cpu < nr_cpu_ids ? cpu : WORK_CPU_UNBOUND;
+}
+
+/**
+ * queue_work_node - queue work on a "random" cpu for a given NUMA node
+ * @node: NUMA node that we are targeting the work for
+ * @wq: workqueue to use
+ * @work: work to queue
+ *
+ * We queue the work to a "random" CPU within a given NUMA node. The basic
+ * idea here is to provide a way to somehow associate work with a given
+ * NUMA node.
+ *
+ * This function will only make a best effort attempt at getting this onto
+ * the right NUMA node. If no node is requested or the requested node is
+ * offline then we just fall back to standard queue_work behavior.
+ *
+ * Currently the "random" CPU ends up being the first available CPU in the
+ * intersection of cpu_online_mask and the cpumask of the node, unless we
+ * are running on the node. In that case we just use the current CPU.
+ *
+ * Return: %false if @work was already on a queue, %true otherwise.
+ */
+bool queue_work_node(int node, struct workqueue_struct *wq,
+		     struct work_struct *work)
+{
+	unsigned long flags;
+	bool ret = false;
+
+	/*
+	 * This current implementation is specific to unbound workqueues.
+	 * Specifically we only return the first available CPU for a given
+	 * node instead of cycling through individual CPUs within the node.
+	 *
+	 * If this is used with a per-cpu workqueue then the logic in
+	 * workqueue_select_cpu_near would need to be updated to allow for
+	 * some round robin type logic.
+	 */
+	WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND));
+
+	local_irq_save(flags);
+
+	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+		int cpu = workqueue_select_cpu_near(node);
+
+		__queue_work(cpu, wq, work);
+		ret = true;
+	}
+
+	local_irq_restore(flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(queue_work_node);
+
 void delayed_work_timer_fn(struct timer_list *t)
 {
 	struct delayed_work *dwork = from_timer(dwork, t, timer);
@@ -1639,7 +1735,7 @@ static void rcu_work_rcufn(struct rcu_head *rcu)
  *
  * Return: %false if @rwork was already pending, %true otherwise.  Note
  * that a full RCU grace period is guaranteed only after a %true return.
- * While @rwork is guarnateed to be executed after a %false return, the
+ * While @rwork is guaranteed to be executed after a %false return, the
  * execution may happen before a full RCU grace period has passed.
  */
 bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork)
@@ -2931,6 +3027,9 @@ static bool __flush_work(struct work_struct *work, bool from_cancel)
 	if (WARN_ON(!wq_online))
 		return false;
 
+	if (WARN_ON(!work->func))
+		return false;
+
 	if (!from_cancel) {
 		lock_map_acquire(&work->lockdep_map);
 		lock_map_release(&work->lockdep_map);
@@ -3337,11 +3436,51 @@ static int init_worker_pool(struct worker_pool *pool)
 	return 0;
 }
 
+#ifdef CONFIG_LOCKDEP
+static void wq_init_lockdep(struct workqueue_struct *wq)
+{
+	char *lock_name;
+
+	lockdep_register_key(&wq->key);
+	lock_name = kasprintf(GFP_KERNEL, "%s%s", "(wq_completion)", wq->name);
+	if (!lock_name)
+		lock_name = wq->name;
+
+	wq->lock_name = lock_name;
+	lockdep_init_map(&wq->lockdep_map, lock_name, &wq->key, 0);
+}
+
+static void wq_unregister_lockdep(struct workqueue_struct *wq)
+{
+	lockdep_unregister_key(&wq->key);
+}
+
+static void wq_free_lockdep(struct workqueue_struct *wq)
+{
+	if (wq->lock_name != wq->name)
+		kfree(wq->lock_name);
+}
+#else
+static void wq_init_lockdep(struct workqueue_struct *wq)
+{
+}
+
+static void wq_unregister_lockdep(struct workqueue_struct *wq)
+{
+}
+
+static void wq_free_lockdep(struct workqueue_struct *wq)
+{
+}
+#endif
+
 static void rcu_free_wq(struct rcu_head *rcu)
 {
 	struct workqueue_struct *wq =
 		container_of(rcu, struct workqueue_struct, rcu);
 
+	wq_free_lockdep(wq);
+
 	if (!(wq->flags & WQ_UNBOUND))
 		free_percpu(wq->cpu_pwqs);
 	else
@@ -3532,8 +3671,10 @@ static void pwq_unbound_release_workfn(struct work_struct *work)
 	 * If we're the last pwq going away, @wq is already dead and no one
 	 * is gonna access it anymore.  Schedule RCU free.
 	 */
-	if (is_last)
+	if (is_last) {
+		wq_unregister_lockdep(wq);
 		call_rcu(&wq->rcu, rcu_free_wq);
+	}
 }
 
 /**
@@ -4067,11 +4208,9 @@ static int init_rescuer(struct workqueue_struct *wq)
 	return 0;
 }
 
-struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
-					       unsigned int flags,
-					       int max_active,
-					       struct lock_class_key *key,
-					       const char *lock_name, ...)
+struct workqueue_struct *alloc_workqueue(const char *fmt,
+					 unsigned int flags,
+					 int max_active, ...)
 {
 	size_t tbl_size = 0;
 	va_list args;
@@ -4106,7 +4245,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
 			goto err_free_wq;
 	}
 
-	va_start(args, lock_name);
+	va_start(args, max_active);
 	vsnprintf(wq->name, sizeof(wq->name), fmt, args);
 	va_end(args);
 
@@ -4123,11 +4262,11 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
 	INIT_LIST_HEAD(&wq->flusher_overflow);
 	INIT_LIST_HEAD(&wq->maydays);
 
-	lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
+	wq_init_lockdep(wq);
 	INIT_LIST_HEAD(&wq->list);
 
 	if (alloc_and_link_pwqs(wq) < 0)
-		goto err_free_wq;
+		goto err_unreg_lockdep;
 
 	if (wq_online && init_rescuer(wq) < 0)
 		goto err_destroy;
@@ -4153,6 +4292,9 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
 
 	return wq;
 
+err_unreg_lockdep:
+	wq_unregister_lockdep(wq);
+	wq_free_lockdep(wq);
 err_free_wq:
 	free_workqueue_attrs(wq->unbound_attrs);
 	kfree(wq);
@@ -4161,7 +4303,7 @@ err_destroy:
 	destroy_workqueue(wq);
 	return NULL;
 }
-EXPORT_SYMBOL_GPL(__alloc_workqueue_key);
+EXPORT_SYMBOL_GPL(alloc_workqueue);
 
 /**
  * destroy_workqueue - safely terminate a workqueue
@@ -4214,6 +4356,7 @@ void destroy_workqueue(struct workqueue_struct *wq)
 		kthread_stop(wq->rescuer->task);
 
 	if (!(wq->flags & WQ_UNBOUND)) {
+		wq_unregister_lockdep(wq);
 		/*
 		 * The base ref is never dropped on per-cpu pwqs.  Directly
 		 * schedule RCU free.