diff options
Diffstat (limited to 'kernel/workqueue.c')
| -rw-r--r-- | kernel/workqueue.c | 903 |
1 files changed, 566 insertions, 337 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index f28849394791..586ad91300b0 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -159,6 +159,7 @@ struct worker_pool { /* see manage_workers() for details on the two manager mutexes */ struct mutex manager_arb; /* manager arbitration */ + struct worker *manager; /* L: purely informational */ struct mutex attach_mutex; /* attach/detach exclusion */ struct list_head workers; /* A: attached workers */ struct completion *detach_completion; /* all workers detached */ @@ -230,7 +231,7 @@ struct wq_device; */ struct workqueue_struct { struct list_head pwqs; /* WR: all pwqs of this wq */ - struct list_head list; /* PL: list of all workqueues */ + struct list_head list; /* PR: list of all workqueues */ struct mutex mutex; /* protects this wq */ int work_color; /* WQ: current work color */ @@ -257,6 +258,13 @@ struct workqueue_struct { #endif char name[WQ_NAME_LEN]; /* I: workqueue name */ + /* + * Destruction of workqueue_struct is sched-RCU protected to allow + * walking the workqueues list without grabbing wq_pool_mutex. + * This is used to dump all workqueues from sysrq. + */ + struct rcu_head rcu; + /* hot fields used during command issue, aligned to cacheline */ unsigned int flags ____cacheline_aligned; /* WQ: WQ_* flags */ struct pool_workqueue __percpu *cpu_pwqs; /* I: per-cpu pwqs */ @@ -288,7 +296,7 @@ static struct workqueue_attrs *wq_update_unbound_numa_attrs_buf; static DEFINE_MUTEX(wq_pool_mutex); /* protects pools and workqueues list */ static DEFINE_SPINLOCK(wq_mayday_lock); /* protects wq->maydays list */ -static LIST_HEAD(workqueues); /* PL: list of all workqueues */ +static LIST_HEAD(workqueues); /* PR: list of all workqueues */ static bool workqueue_freezing; /* PL: have wqs started freezing? */ /* the per-cpu worker pools */ @@ -324,6 +332,7 @@ EXPORT_SYMBOL_GPL(system_freezable_power_efficient_wq); static int worker_thread(void *__worker); static void copy_workqueue_attrs(struct workqueue_attrs *to, const struct workqueue_attrs *from); +static void workqueue_sysfs_unregister(struct workqueue_struct *wq); #define CREATE_TRACE_POINTS #include <trace/events/workqueue.h> @@ -1911,9 +1920,11 @@ static bool manage_workers(struct worker *worker) */ if (!mutex_trylock(&pool->manager_arb)) return false; + pool->manager = worker; maybe_create_worker(pool); + pool->manager = NULL; mutex_unlock(&pool->manager_arb); return true; } @@ -2303,6 +2314,7 @@ repeat: struct wq_barrier { struct work_struct work; struct completion done; + struct task_struct *task; /* purely informational */ }; static void wq_barrier_func(struct work_struct *work) @@ -2351,6 +2363,7 @@ static void insert_wq_barrier(struct pool_workqueue *pwq, INIT_WORK_ONSTACK(&barr->work, wq_barrier_func); __set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work)); init_completion(&barr->done); + barr->task = current; /* * If @target is currently being executed, schedule the @@ -2728,19 +2741,57 @@ bool flush_work(struct work_struct *work) } EXPORT_SYMBOL_GPL(flush_work); +struct cwt_wait { + wait_queue_t wait; + struct work_struct *work; +}; + +static int cwt_wakefn(wait_queue_t *wait, unsigned mode, int sync, void *key) +{ + struct cwt_wait *cwait = container_of(wait, struct cwt_wait, wait); + + if (cwait->work != key) + return 0; + return autoremove_wake_function(wait, mode, sync, key); +} + static bool __cancel_work_timer(struct work_struct *work, bool is_dwork) { + static DECLARE_WAIT_QUEUE_HEAD(cancel_waitq); unsigned long flags; int ret; do { ret = try_to_grab_pending(work, is_dwork, &flags); /* - * If someone else is canceling, wait for the same event it - * would be waiting for before retrying. + * If someone else is already canceling, wait for it to + * finish. flush_work() doesn't work for PREEMPT_NONE + * because we may get scheduled between @work's completion + * and the other canceling task resuming and clearing + * CANCELING - flush_work() will return false immediately + * as @work is no longer busy, try_to_grab_pending() will + * return -ENOENT as @work is still being canceled and the + * other canceling task won't be able to clear CANCELING as + * we're hogging the CPU. + * + * Let's wait for completion using a waitqueue. As this + * may lead to the thundering herd problem, use a custom + * wake function which matches @work along with exclusive + * wait and wakeup. */ - if (unlikely(ret == -ENOENT)) - flush_work(work); + if (unlikely(ret == -ENOENT)) { + struct cwt_wait cwait; + + init_wait(&cwait.wait); + cwait.wait.func = cwt_wakefn; + cwait.work = work; + + prepare_to_wait_exclusive(&cancel_waitq, &cwait.wait, + TASK_UNINTERRUPTIBLE); + if (work_is_canceling(work)) + schedule(); + finish_wait(&cancel_waitq, &cwait.wait); + } } while (unlikely(ret < 0)); /* tell other tasks trying to grab @work to back off */ @@ -2749,6 +2800,16 @@ static bool __cancel_work_timer(struct work_struct *work, bool is_dwork) flush_work(work); clear_work_data(work); + + /* + * Paired with prepare_to_wait() above so that either + * waitqueue_active() is visible here or !work_is_canceling() is + * visible there. + */ + smp_mb(); + if (waitqueue_active(&cancel_waitq)) + __wake_up(&cancel_waitq, TASK_NORMAL, 1, work); + return ret; } @@ -2941,323 +3002,6 @@ int execute_in_process_context(work_func_t fn, struct execute_work *ew) } EXPORT_SYMBOL_GPL(execute_in_process_context); -#ifdef CONFIG_SYSFS -/* - * Workqueues with WQ_SYSFS flag set is visible to userland via - * /sys/bus/workqueue/devices/WQ_NAME. All visible workqueues have the - * following attributes. - * - * per_cpu RO bool : whether the workqueue is per-cpu or unbound - * max_active RW int : maximum number of in-flight work items - * - * Unbound workqueues have the following extra attributes. - * - * id RO int : the associated pool ID - * nice RW int : nice value of the workers - * cpumask RW mask : bitmask of allowed CPUs for the workers - */ -struct wq_device { - struct workqueue_struct *wq; - struct device dev; -}; - -static struct workqueue_struct *dev_to_wq(struct device *dev) -{ - struct wq_device *wq_dev = container_of(dev, struct wq_device, dev); - - return wq_dev->wq; -} - -static ssize_t per_cpu_show(struct device *dev, struct device_attribute *attr, - char *buf) -{ - struct workqueue_struct *wq = dev_to_wq(dev); - - return scnprintf(buf, PAGE_SIZE, "%d\n", (bool)!(wq->flags & WQ_UNBOUND)); -} -static DEVICE_ATTR_RO(per_cpu); - -static ssize_t max_active_show(struct device *dev, - struct device_attribute *attr, char *buf) -{ - struct workqueue_struct *wq = dev_to_wq(dev); - - return scnprintf(buf, PAGE_SIZE, "%d\n", wq->saved_max_active); -} - -static ssize_t max_active_store(struct device *dev, - struct device_attribute *attr, const char *buf, - size_t count) -{ - struct workqueue_struct *wq = dev_to_wq(dev); - int val; - - if (sscanf(buf, "%d", &val) != 1 || val <= 0) - return -EINVAL; - - workqueue_set_max_active(wq, val); - return count; -} -static DEVICE_ATTR_RW(max_active); - -static struct attribute *wq_sysfs_attrs[] = { - &dev_attr_per_cpu.attr, - &dev_attr_max_active.attr, - NULL, -}; -ATTRIBUTE_GROUPS(wq_sysfs); - -static ssize_t wq_pool_ids_show(struct device *dev, - struct device_attribute *attr, char *buf) -{ - struct workqueue_struct *wq = dev_to_wq(dev); - const char *delim = ""; - int node, written = 0; - - rcu_read_lock_sched(); - for_each_node(node) { - written += scnprintf(buf + written, PAGE_SIZE - written, - "%s%d:%d", delim, node, - unbound_pwq_by_node(wq, node)->pool->id); - delim = " "; - } - written += scnprintf(buf + written, PAGE_SIZE - written, "\n"); - rcu_read_unlock_sched(); - - return written; -} - -static ssize_t wq_nice_show(struct device *dev, struct device_attribute *attr, - char *buf) -{ - struct workqueue_struct *wq = dev_to_wq(dev); - int written; - - mutex_lock(&wq->mutex); - written = scnprintf(buf, PAGE_SIZE, "%d\n", wq->unbound_attrs->nice); - mutex_unlock(&wq->mutex); - - return written; -} - -/* prepare workqueue_attrs for sysfs store operations */ -static struct workqueue_attrs *wq_sysfs_prep_attrs(struct workqueue_struct *wq) -{ - struct workqueue_attrs *attrs; - - attrs = alloc_workqueue_attrs(GFP_KERNEL); - if (!attrs) - return NULL; - - mutex_lock(&wq->mutex); - copy_workqueue_attrs(attrs, wq->unbound_attrs); - mutex_unlock(&wq->mutex); - return attrs; -} - -static ssize_t wq_nice_store(struct device *dev, struct device_attribute *attr, - const char *buf, size_t count) -{ - struct workqueue_struct *wq = dev_to_wq(dev); - struct workqueue_attrs *attrs; - int ret; - - attrs = wq_sysfs_prep_attrs(wq); - if (!attrs) - return -ENOMEM; - - if (sscanf(buf, "%d", &attrs->nice) == 1 && - attrs->nice >= MIN_NICE && attrs->nice <= MAX_NICE) - ret = apply_workqueue_attrs(wq, attrs); - else - ret = -EINVAL; - - free_workqueue_attrs(attrs); - return ret ?: count; -} - -static ssize_t wq_cpumask_show(struct device *dev, - struct device_attribute *attr, char *buf) -{ - struct workqueue_struct *wq = dev_to_wq(dev); - int written; - - mutex_lock(&wq->mutex); - written = scnprintf(buf, PAGE_SIZE, "%*pb\n", - cpumask_pr_args(wq->unbound_attrs->cpumask)); - mutex_unlock(&wq->mutex); - return written; -} - -static ssize_t wq_cpumask_store(struct device *dev, - struct device_attribute *attr, - const char *buf, size_t count) -{ - struct workqueue_struct *wq = dev_to_wq(dev); - struct workqueue_attrs *attrs; - int ret; - - attrs = wq_sysfs_prep_attrs(wq); - if (!attrs) - return -ENOMEM; - - ret = cpumask_parse(buf, attrs->cpumask); - if (!ret) - ret = apply_workqueue_attrs(wq, attrs); - - free_workqueue_attrs(attrs); - return ret ?: count; -} - -static ssize_t wq_numa_show(struct device *dev, struct device_attribute *attr, - char *buf) -{ - struct workqueue_struct *wq = dev_to_wq(dev); - int written; - - mutex_lock(&wq->mutex); - written = scnprintf(buf, PAGE_SIZE, "%d\n", - !wq->unbound_attrs->no_numa); - mutex_unlock(&wq->mutex); - - return written; -} - -static ssize_t wq_numa_store(struct device *dev, struct device_attribute *attr, - const char *buf, size_t count) -{ - struct workqueue_struct *wq = dev_to_wq(dev); - struct workqueue_attrs *attrs; - int v, ret; - - attrs = wq_sysfs_prep_attrs(wq); - if (!attrs) - return -ENOMEM; - - ret = -EINVAL; - if (sscanf(buf, "%d", &v) == 1) { - attrs->no_numa = !v; - ret = apply_workqueue_attrs(wq, attrs); - } - - free_workqueue_attrs(attrs); - return ret ?: count; -} - -static struct device_attribute wq_sysfs_unbound_attrs[] = { - __ATTR(pool_ids, 0444, wq_pool_ids_show, NULL), - __ATTR(nice, 0644, wq_nice_show, wq_nice_store), - __ATTR(cpumask, 0644, wq_cpumask_show, wq_cpumask_store), - __ATTR(numa, 0644, wq_numa_show, wq_numa_store), - __ATTR_NULL, -}; - -static struct bus_type wq_subsys = { - .name = "workqueue", - .dev_groups = wq_sysfs_groups, -}; - -static int __init wq_sysfs_init(void) -{ - return subsys_virtual_register(&wq_subsys, NULL); -} -core_initcall(wq_sysfs_init); - -static void wq_device_release(struct device *dev) -{ - struct wq_device *wq_dev = container_of(dev, struct wq_device, dev); - - kfree(wq_dev); -} - -/** - * workqueue_sysfs_register - make a workqueue visible in sysfs - * @wq: the workqueue to register - * - * Expose @wq in sysfs under /sys/bus/workqueue/devices. - * alloc_workqueue*() automatically calls this function if WQ_SYSFS is set - * which is the preferred method. - * - * Workqueue user should use this function directly iff it wants to apply - * workqueue_attrs before making the workqueue visible in sysfs; otherwise, - * apply_workqueue_attrs() may race against userland updating the - * attributes. - * - * Return: 0 on success, -errno on failure. - */ -int workqueue_sysfs_register(struct workqueue_struct *wq) -{ - struct wq_device *wq_dev; - int ret; - - /* - * Adjusting max_active or creating new pwqs by applyting - * attributes breaks ordering guarantee. Disallow exposing ordered - * workqueues. - */ - if (WARN_ON(wq->flags & __WQ_ORDERED)) - return -EINVAL; - - wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL); - if (!wq_dev) - return -ENOMEM; - - wq_dev->wq = wq; - wq_dev->dev.bus = &wq_subsys; - wq_dev->dev.init_name = wq->name; - wq_dev->dev.release = wq_device_release; - - /* - * unbound_attrs are created separately. Suppress uevent until - * everything is ready. - */ - dev_set_uevent_suppress(&wq_dev->dev, true); - - ret = device_register(&wq_dev->dev); - if (ret) { - kfree(wq_dev); - wq->wq_dev = NULL; - return ret; - } - - if (wq->flags & WQ_UNBOUND) { - struct device_attribute *attr; - - for (attr = wq_sysfs_unbound_attrs; attr->attr.name; attr++) { - ret = device_create_file(&wq_dev->dev, attr); - if (ret) { - device_unregister(&wq_dev->dev); - wq->wq_dev = NULL; - return ret; - } - } - } - - dev_set_uevent_suppress(&wq_dev->dev, false); - kobject_uevent(&wq_dev->dev.kobj, KOBJ_ADD); - return 0; -} - -/** - * workqueue_sysfs_unregister - undo workqueue_sysfs_register() - * @wq: the workqueue to unregister - * - * If @wq is registered to sysfs by workqueue_sysfs_register(), unregister. - */ -static void workqueue_sysfs_unregister(struct workqueue_struct *wq) -{ - struct wq_device *wq_dev = wq->wq_dev; - - if (!wq->wq_dev) - return; - - wq->wq_dev = NULL; - device_unregister(&wq_dev->dev); -} -#else /* CONFIG_SYSFS */ -static void workqueue_sysfs_unregister(struct workqueue_struct *wq) { } -#endif /* CONFIG_SYSFS */ - /** * free_workqueue_attrs - free a workqueue_attrs * @attrs: workqueue_attrs to free @@ -3376,6 +3120,20 @@ static int init_worker_pool(struct worker_pool *pool) return 0; } +static void rcu_free_wq(struct rcu_head *rcu) +{ + struct workqueue_struct *wq = + container_of(rcu, struct workqueue_struct, rcu); + + if (!(wq->flags & WQ_UNBOUND)) + free_percpu(wq->cpu_pwqs); + else + free_workqueue_attrs(wq->unbound_attrs); + + kfree(wq->rescuer); + kfree(wq); +} + static void rcu_free_pool(struct rcu_head *rcu) { struct worker_pool *pool = container_of(rcu, struct worker_pool, rcu); @@ -3553,12 +3311,10 @@ 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. Free it. + * is gonna access it anymore. Schedule RCU free. */ - if (is_last) { - free_workqueue_attrs(wq->unbound_attrs); - kfree(wq); - } + if (is_last) + call_rcu_sched(&wq->rcu, rcu_free_wq); } /** @@ -4095,7 +3851,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt, pwq_adjust_max_active(pwq); mutex_unlock(&wq->mutex); - list_add(&wq->list, &workqueues); + list_add_tail_rcu(&wq->list, &workqueues); mutex_unlock(&wq_pool_mutex); @@ -4151,24 +3907,20 @@ void destroy_workqueue(struct workqueue_struct *wq) * flushing is complete in case freeze races us. */ mutex_lock(&wq_pool_mutex); - list_del_init(&wq->list); + list_del_rcu(&wq->list); mutex_unlock(&wq_pool_mutex); workqueue_sysfs_unregister(wq); - if (wq->rescuer) { + if (wq->rescuer) kthread_stop(wq->rescuer->task); - kfree(wq->rescuer); - wq->rescuer = NULL; - } if (!(wq->flags & WQ_UNBOUND)) { /* * The base ref is never dropped on per-cpu pwqs. Directly - * free the pwqs and wq. + * schedule RCU free. */ - free_percpu(wq->cpu_pwqs); - kfree(wq); + call_rcu_sched(&wq->rcu, rcu_free_wq); } else { /* * We're the sole accessor of @wq at this point. Directly @@ -4389,6 +4141,166 @@ void print_worker_info(const char *log_lvl, struct task_struct *task) } } +static void pr_cont_pool_info(struct worker_pool *pool) +{ + pr_cont(" cpus=%*pbl", nr_cpumask_bits, pool->attrs->cpumask); + if (pool->node != NUMA_NO_NODE) + pr_cont(" node=%d", pool->node); + pr_cont(" flags=0x%x nice=%d", pool->flags, pool->attrs->nice); +} + +static void pr_cont_work(bool comma, struct work_struct *work) +{ + if (work->func == wq_barrier_func) { + struct wq_barrier *barr; + + barr = container_of(work, struct wq_barrier, work); + + pr_cont("%s BAR(%d)", comma ? "," : "", + task_pid_nr(barr->task)); + } else { + pr_cont("%s %pf", comma ? "," : "", work->func); + } +} + +static void show_pwq(struct pool_workqueue *pwq) +{ + struct worker_pool *pool = pwq->pool; + struct work_struct *work; + struct worker *worker; + bool has_in_flight = false, has_pending = false; + int bkt; + + pr_info(" pwq %d:", pool->id); + pr_cont_pool_info(pool); + + pr_cont(" active=%d/%d%s\n", pwq->nr_active, pwq->max_active, + !list_empty(&pwq->mayday_node) ? " MAYDAY" : ""); + + hash_for_each(pool->busy_hash, bkt, worker, hentry) { + if (worker->current_pwq == pwq) { + has_in_flight = true; + break; + } + } + if (has_in_flight) { + bool comma = false; + + pr_info(" in-flight:"); + hash_for_each(pool->busy_hash, bkt, worker, hentry) { + if (worker->current_pwq != pwq) + continue; + + pr_cont("%s %d%s:%pf", comma ? "," : "", + task_pid_nr(worker->task), + worker == pwq->wq->rescuer ? "(RESCUER)" : "", + worker->current_func); + list_for_each_entry(work, &worker->scheduled, entry) + pr_cont_work(false, work); + comma = true; + } + pr_cont("\n"); + } + + list_for_each_entry(work, &pool->worklist, entry) { + if (get_work_pwq(work) == pwq) { + has_pending = true; + break; + } + } + if (has_pending) { + bool comma = false; + + pr_info(" pending:"); + list_for_each_entry(work, &pool->worklist, entry) { + if (get_work_pwq(work) != pwq) + continue; + + pr_cont_work(comma, work); + comma = !(*work_data_bits(work) & WORK_STRUCT_LINKED); + } + pr_cont("\n"); + } + + if (!list_empty(&pwq->delayed_works)) { + bool comma = false; + + pr_info(" delayed:"); + list_for_each_entry(work, &pwq->delayed_works, entry) { + pr_cont_work(comma, work); + comma = !(*work_data_bits(work) & WORK_STRUCT_LINKED); + } + pr_cont("\n"); + } +} + +/** + * show_workqueue_state - dump workqueue state + * + * Called from a sysrq handler and prints out all busy workqueues and + * pools. + */ +void show_workqueue_state(void) +{ + struct workqueue_struct *wq; + struct worker_pool *pool; + unsigned long flags; + int pi; + + rcu_read_lock_sched(); + + pr_info("Showing busy workqueues and worker pools:\n"); + + list_for_each_entry_rcu(wq, &workqueues, list) { + struct pool_workqueue *pwq; + bool idle = true; + + for_each_pwq(pwq, wq) { + if (pwq->nr_active || !list_empty(&pwq->delayed_works)) { + idle = false; + break; + } + } + if (idle) + continue; + + pr_info("workqueue %s: flags=0x%x\n", wq->name, wq->flags); + + for_each_pwq(pwq, wq) { + spin_lock_irqsave(&pwq->pool->lock, flags); + if (pwq->nr_active || !list_empty(&pwq->delayed_works)) + show_pwq(pwq); + spin_unlock_irqrestore(&pwq->pool->lock, flags); + } + } + + for_each_pool(pool, pi) { + struct worker *worker; + bool first = true; + + spin_lock_irqsave(&pool->lock, flags); + if (pool->nr_workers == pool->nr_idle) + goto next_pool; + + pr_info("pool %d:", pool->id); + pr_cont_pool_info(pool); + pr_cont(" workers=%d", pool->nr_workers); + if (pool->manager) + pr_cont(" manager: %d", + task_pid_nr(pool->manager->task)); + list_for_each_entry(worker, &pool->idle_list, entry) { + pr_cont(" %s%d", first ? "idle: " : "", + task_pid_nr(worker->task)); + first = false; + } + pr_cont("\n"); + next_pool: + spin_unlock_irqrestore(&pool->lock, flags); + } + + rcu_read_unlock_sched(); +} + /* * CPU hotplug. * @@ -4786,6 +4698,323 @@ out_unlock: } #endif /* CONFIG_FREEZER */ +#ifdef CONFIG_SYSFS +/* + * Workqueues with WQ_SYSFS flag set is visible to userland via + * /sys/bus/workqueue/devices/WQ_NAME. All visible workqueues have the + * following attributes. + * + * per_cpu RO bool : whether the workqueue is per-cpu or unbound + * max_active RW int : maximum number of in-flight work items + * + * Unbound workqueues have the following extra attributes. + * + * id RO int : the associated pool ID + * nice RW int : nice value of the workers + * cpumask RW mask : bitmask of allowed CPUs for the workers + */ +struct wq_device { + struct workqueue_struct *wq; + struct device dev; +}; + +static struct workqueue_struct *dev_to_wq(struct device *dev) +{ + struct wq_device *wq_dev = container_of(dev, struct wq_device, dev); + + return wq_dev->wq; +} + +static ssize_t per_cpu_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct workqueue_struct *wq = dev_to_wq(dev); + + return scnprintf(buf, PAGE_SIZE, "%d\n", (bool)!(wq->flags & WQ_UNBOUND)); +} +static DEVICE_ATTR_RO(per_cpu); + +static ssize_t max_active_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct workqueue_struct *wq = dev_to_wq(dev); + + return scnprintf(buf, PAGE_SIZE, "%d\n", wq->saved_max_active); +} + +static ssize_t max_active_store(struct device *dev, + struct device_attribute *attr, const char *buf, + size_t count) +{ + struct workqueue_struct *wq = dev_to_wq(dev); + int val; + + if (sscanf(buf, "%d", &val) != 1 || val <= 0) + return -EINVAL; + + workqueue_set_max_active(wq, val); + return count; +} +static DEVICE_ATTR_RW(max_active); + +static struct attribute *wq_sysfs_attrs[] = { + &dev_attr_per_cpu.attr, + &dev_attr_max_active.attr, + NULL, +}; +ATTRIBUTE_GROUPS(wq_sysfs); + +static ssize_t wq_pool_ids_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct workqueue_struct *wq = dev_to_wq(dev); + const char *delim = ""; + int node, written = 0; + + rcu_read_lock_sched(); + for_each_node(node) { + written += scnprintf(buf + written, PAGE_SIZE - written, + "%s%d:%d", delim, node, + unbound_pwq_by_node(wq, node)->pool->id); + delim = " "; + } + written += scnprintf(buf + written, PAGE_SIZE - written, "\n"); + rcu_read_unlock_sched(); + + return written; +} + +static ssize_t wq_nice_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct workqueue_struct *wq = dev_to_wq(dev); + int written; + + mutex_lock(&wq->mutex); + written = scnprintf(buf, PAGE_SIZE, "%d\n", wq->unbound_attrs->nice); + mutex_unlock(&wq->mutex); + + return written; +} + +/* prepare workqueue_attrs for sysfs store operations */ +static struct workqueue_attrs *wq_sysfs_prep_attrs(struct workqueue_struct *wq) +{ + struct workqueue_attrs *attrs; + + attrs = alloc_workqueue_attrs(GFP_KERNEL); + if (!attrs) + return NULL; + + mutex_lock(&wq->mutex); + copy_workqueue_attrs(attrs, wq->unbound_attrs); + mutex_unlock(&wq->mutex); + return attrs; +} + +static ssize_t wq_nice_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct workqueue_struct *wq = dev_to_wq(dev); + struct workqueue_attrs *attrs; + int ret; + + attrs = wq_sysfs_prep_attrs(wq); + if (!attrs) + return -ENOMEM; + + if (sscanf(buf, "%d", &attrs->nice) == 1 && + attrs->nice >= MIN_NICE && attrs->nice <= MAX_NICE) + ret = apply_workqueue_attrs(wq, attrs); + else + ret = -EINVAL; + + free_workqueue_attrs(attrs); + return ret ?: count; +} + +static ssize_t wq_cpumask_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct workqueue_struct *wq = dev_to_wq(dev); + int written; + + mutex_lock(&wq->mutex); + written = scnprintf(buf, PAGE_SIZE, "%*pb\n", + cpumask_pr_args(wq->unbound_attrs->cpumask)); + mutex_unlock(&wq->mutex); + return written; +} + +static ssize_t wq_cpumask_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct workqueue_struct *wq = dev_to_wq(dev); + struct workqueue_attrs *attrs; + int ret; + + attrs = wq_sysfs_prep_attrs(wq); + if (!attrs) + return -ENOMEM; + + ret = cpumask_parse(buf, attrs->cpumask); + if (!ret) + ret = apply_workqueue_attrs(wq, attrs); + + free_workqueue_attrs(attrs); + return ret ?: count; +} + +static ssize_t wq_numa_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct workqueue_struct *wq = dev_to_wq(dev); + int written; + + mutex_lock(&wq->mutex); + written = scnprintf(buf, PAGE_SIZE, "%d\n", + !wq->unbound_attrs->no_numa); + mutex_unlock(&wq->mutex); + + return written; +} + +static ssize_t wq_numa_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct workqueue_struct *wq = dev_to_wq(dev); + struct workqueue_attrs *attrs; + int v, ret; + + attrs = wq_sysfs_prep_attrs(wq); + if (!attrs) + return -ENOMEM; + + ret = -EINVAL; + if (sscanf(buf, "%d", &v) == 1) { + attrs->no_numa = !v; + ret = apply_workqueue_attrs(wq, attrs); + } + + free_workqueue_attrs(attrs); + return ret ?: count; +} + +static struct device_attribute wq_sysfs_unbound_attrs[] = { + __ATTR(pool_ids, 0444, wq_pool_ids_show, NULL), + __ATTR(nice, 0644, wq_nice_show, wq_nice_store), + __ATTR(cpumask, 0644, wq_cpumask_show, wq_cpumask_store), + __ATTR(numa, 0644, wq_numa_show, wq_numa_store), + __ATTR_NULL, +}; + +static struct bus_type wq_subsys = { + .name = "workqueue", + .dev_groups = wq_sysfs_groups, +}; + +static int __init wq_sysfs_init(void) +{ + return subsys_virtual_register(&wq_subsys, NULL); +} +core_initcall(wq_sysfs_init); + +static void wq_device_release(struct device *dev) +{ + struct wq_device *wq_dev = container_of(dev, struct wq_device, dev); + + kfree(wq_dev); +} + +/** + * workqueue_sysfs_register - make a workqueue visible in sysfs + * @wq: the workqueue to register + * + * Expose @wq in sysfs under /sys/bus/workqueue/devices. + * alloc_workqueue*() automatically calls this function if WQ_SYSFS is set + * which is the preferred method. + * + * Workqueue user should use this function directly iff it wants to apply + * workqueue_attrs before making the workqueue visible in sysfs; otherwise, + * apply_workqueue_attrs() may race against userland updating the + * attributes. + * + * Return: 0 on success, -errno on failure. + */ +int workqueue_sysfs_register(struct workqueue_struct *wq) +{ + struct wq_device *wq_dev; + int ret; + + /* + * Adjusting max_active or creating new pwqs by applyting + * attributes breaks ordering guarantee. Disallow exposing ordered + * workqueues. + */ + if (WARN_ON(wq->flags & __WQ_ORDERED)) + return -EINVAL; + + wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL); + if (!wq_dev) + return -ENOMEM; + + wq_dev->wq = wq; + wq_dev->dev.bus = &wq_subsys; + wq_dev->dev.init_name = wq->name; + wq_dev->dev.release = wq_device_release; + + /* + * unbound_attrs are created separately. Suppress uevent until + * everything is ready. + */ + dev_set_uevent_suppress(&wq_dev->dev, true); + + ret = device_register(&wq_dev->dev); + if (ret) { + kfree(wq_dev); + wq->wq_dev = NULL; + return ret; + } + + if (wq->flags & WQ_UNBOUND) { + struct device_attribute *attr; + + for (attr = wq_sysfs_unbound_attrs; attr->attr.name; attr++) { + ret = device_create_file(&wq_dev->dev, attr); + if (ret) { + device_unregister(&wq_dev->dev); + wq->wq_dev = NULL; + return ret; + } + } + } + + dev_set_uevent_suppress(&wq_dev->dev, false); + kobject_uevent(&wq_dev->dev.kobj, KOBJ_ADD); + return 0; +} + +/** + * workqueue_sysfs_unregister - undo workqueue_sysfs_register() + * @wq: the workqueue to unregister + * + * If @wq is registered to sysfs by workqueue_sysfs_register(), unregister. + */ +static void workqueue_sysfs_unregister(struct workqueue_struct *wq) +{ + struct wq_device *wq_dev = wq->wq_dev; + + if (!wq->wq_dev) + return; + + wq->wq_dev = NULL; + device_unregister(&wq_dev->dev); +} +#else /* CONFIG_SYSFS */ +static void workqueue_sysfs_unregister(struct workqueue_struct *wq) { } +#endif /* CONFIG_SYSFS */ + static void __init wq_numa_init(void) { cpumask_var_t *tbl; |