diff options
Diffstat (limited to 'kernel/workqueue.c')
| -rw-r--r-- | kernel/workqueue.c | 185 |
1 files changed, 173 insertions, 12 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 392be4b252f6..7abbeed13421 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 @@ -910,6 +912,36 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task) } /** + * wq_worker_last_func - retrieve worker's last work function + * + * Determine the last function a worker executed. This is called from + * the scheduler to get a worker's last known identity. + * + * 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. + */ +work_func_t wq_worker_last_func(struct task_struct *task) +{ + struct worker *worker = kthread_data(task); + + return worker->last_func; +} + +/** * worker_set_flags - set worker flags and adjust nr_running accordingly * @worker: self * @flags: flags to set @@ -1321,7 +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; @@ -1492,6 +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); @@ -1619,7 +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) @@ -2184,6 +2300,9 @@ __acquires(&pool->lock) if (unlikely(cpu_intensive)) worker_clr_flags(worker, WORKER_CPU_INTENSIVE); + /* tag the worker for identification in schedule() */ + worker->last_func = worker->current_func; + /* we're done with it, release */ hash_del(&worker->hentry); worker->current_work = NULL; @@ -2908,6 +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); @@ -3314,11 +3436,49 @@ 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; + 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 @@ -3509,8 +3669,10 @@ 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); + } } /** @@ -4044,11 +4206,9 @@ 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; @@ -4083,7 +4243,7 @@ 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); @@ -4100,7 +4260,7 @@ 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) @@ -4138,7 +4298,7 @@ err_destroy: destroy_workqueue(wq); return NULL; } -EXPORT_SYMBOL_GPL(__alloc_workqueue_key); +EXPORT_SYMBOL_GPL(alloc_workqueue); /** * destroy_workqueue - safely terminate a workqueue @@ -4191,6 +4351,7 @@ 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. |