11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * linux/kernel/workqueue.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Generic mechanism for defining kernel helper threads for running 51da177e4SLinus Torvalds * arbitrary tasks in process context. 61da177e4SLinus Torvalds * 71da177e4SLinus Torvalds * Started by Ingo Molnar, Copyright (C) 2002 81da177e4SLinus Torvalds * 91da177e4SLinus Torvalds * Derived from the taskqueue/keventd code by: 101da177e4SLinus Torvalds * 111da177e4SLinus Torvalds * David Woodhouse <dwmw2@infradead.org> 121da177e4SLinus Torvalds * Andrew Morton <andrewm@uow.edu.au> 131da177e4SLinus Torvalds * Kai Petzke <wpp@marie.physik.tu-berlin.de> 141da177e4SLinus Torvalds * Theodore Ts'o <tytso@mit.edu> 1589ada679SChristoph Lameter * 1689ada679SChristoph Lameter * Made to use alloc_percpu by Christoph Lameter <clameter@sgi.com>. 171da177e4SLinus Torvalds */ 181da177e4SLinus Torvalds 191da177e4SLinus Torvalds #include <linux/module.h> 201da177e4SLinus Torvalds #include <linux/kernel.h> 211da177e4SLinus Torvalds #include <linux/sched.h> 221da177e4SLinus Torvalds #include <linux/init.h> 231da177e4SLinus Torvalds #include <linux/signal.h> 241da177e4SLinus Torvalds #include <linux/completion.h> 251da177e4SLinus Torvalds #include <linux/workqueue.h> 261da177e4SLinus Torvalds #include <linux/slab.h> 271da177e4SLinus Torvalds #include <linux/cpu.h> 281da177e4SLinus Torvalds #include <linux/notifier.h> 291da177e4SLinus Torvalds #include <linux/kthread.h> 301fa44ecaSJames Bottomley #include <linux/hardirq.h> 3146934023SChristoph Lameter #include <linux/mempolicy.h> 321da177e4SLinus Torvalds 331da177e4SLinus Torvalds /* 34f756d5e2SNathan Lynch * The per-CPU workqueue (if single thread, we always use the first 35f756d5e2SNathan Lynch * possible cpu). 361da177e4SLinus Torvalds * 371da177e4SLinus Torvalds * The sequence counters are for flush_scheduled_work(). It wants to wait 389f5d785eSRolf Eike Beer * until all currently-scheduled works are completed, but it doesn't 391da177e4SLinus Torvalds * want to be livelocked by new, incoming ones. So it waits until 401da177e4SLinus Torvalds * remove_sequence is >= the insert_sequence which pertained when 411da177e4SLinus Torvalds * flush_scheduled_work() was called. 421da177e4SLinus Torvalds */ 431da177e4SLinus Torvalds struct cpu_workqueue_struct { 441da177e4SLinus Torvalds 451da177e4SLinus Torvalds spinlock_t lock; 461da177e4SLinus Torvalds 471da177e4SLinus Torvalds long remove_sequence; /* Least-recently added (next to run) */ 481da177e4SLinus Torvalds long insert_sequence; /* Next to add */ 491da177e4SLinus Torvalds 501da177e4SLinus Torvalds struct list_head worklist; 511da177e4SLinus Torvalds wait_queue_head_t more_work; 521da177e4SLinus Torvalds wait_queue_head_t work_done; 531da177e4SLinus Torvalds 541da177e4SLinus Torvalds struct workqueue_struct *wq; 5536c8b586SIngo Molnar struct task_struct *thread; 561da177e4SLinus Torvalds 571da177e4SLinus Torvalds int run_depth; /* Detect run_workqueue() recursion depth */ 581da177e4SLinus Torvalds } ____cacheline_aligned; 591da177e4SLinus Torvalds 601da177e4SLinus Torvalds /* 611da177e4SLinus Torvalds * The externally visible workqueue abstraction is an array of 621da177e4SLinus Torvalds * per-CPU workqueues: 631da177e4SLinus Torvalds */ 641da177e4SLinus Torvalds struct workqueue_struct { 6589ada679SChristoph Lameter struct cpu_workqueue_struct *cpu_wq; 661da177e4SLinus Torvalds const char *name; 671da177e4SLinus Torvalds struct list_head list; /* Empty if single thread */ 681da177e4SLinus Torvalds }; 691da177e4SLinus Torvalds 701da177e4SLinus Torvalds /* All the per-cpu workqueues on the system, for hotplug cpu to add/remove 711da177e4SLinus Torvalds threads to each one as cpus come/go. */ 729b41ea72SAndrew Morton static DEFINE_MUTEX(workqueue_mutex); 731da177e4SLinus Torvalds static LIST_HEAD(workqueues); 741da177e4SLinus Torvalds 75f756d5e2SNathan Lynch static int singlethread_cpu; 76f756d5e2SNathan Lynch 771da177e4SLinus Torvalds /* If it's single threaded, it isn't in the list of workqueues. */ 781da177e4SLinus Torvalds static inline int is_single_threaded(struct workqueue_struct *wq) 791da177e4SLinus Torvalds { 801da177e4SLinus Torvalds return list_empty(&wq->list); 811da177e4SLinus Torvalds } 821da177e4SLinus Torvalds 831da177e4SLinus Torvalds /* Preempt must be disabled. */ 841da177e4SLinus Torvalds static void __queue_work(struct cpu_workqueue_struct *cwq, 851da177e4SLinus Torvalds struct work_struct *work) 861da177e4SLinus Torvalds { 871da177e4SLinus Torvalds unsigned long flags; 881da177e4SLinus Torvalds 891da177e4SLinus Torvalds spin_lock_irqsave(&cwq->lock, flags); 901da177e4SLinus Torvalds work->wq_data = cwq; 911da177e4SLinus Torvalds list_add_tail(&work->entry, &cwq->worklist); 921da177e4SLinus Torvalds cwq->insert_sequence++; 931da177e4SLinus Torvalds wake_up(&cwq->more_work); 941da177e4SLinus Torvalds spin_unlock_irqrestore(&cwq->lock, flags); 951da177e4SLinus Torvalds } 961da177e4SLinus Torvalds 970fcb78c2SRolf Eike Beer /** 980fcb78c2SRolf Eike Beer * queue_work - queue work on a workqueue 990fcb78c2SRolf Eike Beer * @wq: workqueue to use 1000fcb78c2SRolf Eike Beer * @work: work to queue 1010fcb78c2SRolf Eike Beer * 102057647fcSAlan Stern * Returns 0 if @work was already on a queue, non-zero otherwise. 1031da177e4SLinus Torvalds * 1041da177e4SLinus Torvalds * We queue the work to the CPU it was submitted, but there is no 1051da177e4SLinus Torvalds * guarantee that it will be processed by that CPU. 1061da177e4SLinus Torvalds */ 1071da177e4SLinus Torvalds int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work) 1081da177e4SLinus Torvalds { 1091da177e4SLinus Torvalds int ret = 0, cpu = get_cpu(); 1101da177e4SLinus Torvalds 1111da177e4SLinus Torvalds if (!test_and_set_bit(0, &work->pending)) { 1121da177e4SLinus Torvalds if (unlikely(is_single_threaded(wq))) 113f756d5e2SNathan Lynch cpu = singlethread_cpu; 1141da177e4SLinus Torvalds BUG_ON(!list_empty(&work->entry)); 11589ada679SChristoph Lameter __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work); 1161da177e4SLinus Torvalds ret = 1; 1171da177e4SLinus Torvalds } 1181da177e4SLinus Torvalds put_cpu(); 1191da177e4SLinus Torvalds return ret; 1201da177e4SLinus Torvalds } 121ae90dd5dSDave Jones EXPORT_SYMBOL_GPL(queue_work); 1221da177e4SLinus Torvalds 1231da177e4SLinus Torvalds static void delayed_work_timer_fn(unsigned long __data) 1241da177e4SLinus Torvalds { 12552bad64dSDavid Howells struct delayed_work *dwork = (struct delayed_work *)__data; 12652bad64dSDavid Howells struct workqueue_struct *wq = dwork->work.wq_data; 1271da177e4SLinus Torvalds int cpu = smp_processor_id(); 1281da177e4SLinus Torvalds 1291da177e4SLinus Torvalds if (unlikely(is_single_threaded(wq))) 130f756d5e2SNathan Lynch cpu = singlethread_cpu; 1311da177e4SLinus Torvalds 13252bad64dSDavid Howells __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), &dwork->work); 1331da177e4SLinus Torvalds } 1341da177e4SLinus Torvalds 1350fcb78c2SRolf Eike Beer /** 1360fcb78c2SRolf Eike Beer * queue_delayed_work - queue work on a workqueue after delay 1370fcb78c2SRolf Eike Beer * @wq: workqueue to use 13852bad64dSDavid Howells * @work: delayable work to queue 1390fcb78c2SRolf Eike Beer * @delay: number of jiffies to wait before queueing 1400fcb78c2SRolf Eike Beer * 141057647fcSAlan Stern * Returns 0 if @work was already on a queue, non-zero otherwise. 1420fcb78c2SRolf Eike Beer */ 1431da177e4SLinus Torvalds int fastcall queue_delayed_work(struct workqueue_struct *wq, 14452bad64dSDavid Howells struct delayed_work *dwork, unsigned long delay) 1451da177e4SLinus Torvalds { 1461da177e4SLinus Torvalds int ret = 0; 14752bad64dSDavid Howells struct timer_list *timer = &dwork->timer; 14852bad64dSDavid Howells struct work_struct *work = &dwork->work; 14952bad64dSDavid Howells 15052bad64dSDavid Howells if (delay == 0) 15152bad64dSDavid Howells return queue_work(wq, work); 1521da177e4SLinus Torvalds 1531da177e4SLinus Torvalds if (!test_and_set_bit(0, &work->pending)) { 1541da177e4SLinus Torvalds BUG_ON(timer_pending(timer)); 1551da177e4SLinus Torvalds BUG_ON(!list_empty(&work->entry)); 1561da177e4SLinus Torvalds 1571da177e4SLinus Torvalds /* This stores wq for the moment, for the timer_fn */ 1581da177e4SLinus Torvalds work->wq_data = wq; 1591da177e4SLinus Torvalds timer->expires = jiffies + delay; 16052bad64dSDavid Howells timer->data = (unsigned long)dwork; 1611da177e4SLinus Torvalds timer->function = delayed_work_timer_fn; 1621da177e4SLinus Torvalds add_timer(timer); 1631da177e4SLinus Torvalds ret = 1; 1641da177e4SLinus Torvalds } 1651da177e4SLinus Torvalds return ret; 1661da177e4SLinus Torvalds } 167ae90dd5dSDave Jones EXPORT_SYMBOL_GPL(queue_delayed_work); 1681da177e4SLinus Torvalds 1690fcb78c2SRolf Eike Beer /** 1700fcb78c2SRolf Eike Beer * queue_delayed_work_on - queue work on specific CPU after delay 1710fcb78c2SRolf Eike Beer * @cpu: CPU number to execute work on 1720fcb78c2SRolf Eike Beer * @wq: workqueue to use 1730fcb78c2SRolf Eike Beer * @work: work to queue 1740fcb78c2SRolf Eike Beer * @delay: number of jiffies to wait before queueing 1750fcb78c2SRolf Eike Beer * 176057647fcSAlan Stern * Returns 0 if @work was already on a queue, non-zero otherwise. 1770fcb78c2SRolf Eike Beer */ 1787a6bc1cdSVenkatesh Pallipadi int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, 17952bad64dSDavid Howells struct delayed_work *dwork, unsigned long delay) 1807a6bc1cdSVenkatesh Pallipadi { 1817a6bc1cdSVenkatesh Pallipadi int ret = 0; 18252bad64dSDavid Howells struct timer_list *timer = &dwork->timer; 18352bad64dSDavid Howells struct work_struct *work = &dwork->work; 1847a6bc1cdSVenkatesh Pallipadi 1857a6bc1cdSVenkatesh Pallipadi if (!test_and_set_bit(0, &work->pending)) { 1867a6bc1cdSVenkatesh Pallipadi BUG_ON(timer_pending(timer)); 1877a6bc1cdSVenkatesh Pallipadi BUG_ON(!list_empty(&work->entry)); 1887a6bc1cdSVenkatesh Pallipadi 1897a6bc1cdSVenkatesh Pallipadi /* This stores wq for the moment, for the timer_fn */ 1907a6bc1cdSVenkatesh Pallipadi work->wq_data = wq; 1917a6bc1cdSVenkatesh Pallipadi timer->expires = jiffies + delay; 19252bad64dSDavid Howells timer->data = (unsigned long)dwork; 1937a6bc1cdSVenkatesh Pallipadi timer->function = delayed_work_timer_fn; 1947a6bc1cdSVenkatesh Pallipadi add_timer_on(timer, cpu); 1957a6bc1cdSVenkatesh Pallipadi ret = 1; 1967a6bc1cdSVenkatesh Pallipadi } 1977a6bc1cdSVenkatesh Pallipadi return ret; 1987a6bc1cdSVenkatesh Pallipadi } 199ae90dd5dSDave Jones EXPORT_SYMBOL_GPL(queue_delayed_work_on); 2001da177e4SLinus Torvalds 201858119e1SArjan van de Ven static void run_workqueue(struct cpu_workqueue_struct *cwq) 2021da177e4SLinus Torvalds { 2031da177e4SLinus Torvalds unsigned long flags; 2041da177e4SLinus Torvalds 2051da177e4SLinus Torvalds /* 2061da177e4SLinus Torvalds * Keep taking off work from the queue until 2071da177e4SLinus Torvalds * done. 2081da177e4SLinus Torvalds */ 2091da177e4SLinus Torvalds spin_lock_irqsave(&cwq->lock, flags); 2101da177e4SLinus Torvalds cwq->run_depth++; 2111da177e4SLinus Torvalds if (cwq->run_depth > 3) { 2121da177e4SLinus Torvalds /* morton gets to eat his hat */ 2131da177e4SLinus Torvalds printk("%s: recursion depth exceeded: %d\n", 2141da177e4SLinus Torvalds __FUNCTION__, cwq->run_depth); 2151da177e4SLinus Torvalds dump_stack(); 2161da177e4SLinus Torvalds } 2171da177e4SLinus Torvalds while (!list_empty(&cwq->worklist)) { 2181da177e4SLinus Torvalds struct work_struct *work = list_entry(cwq->worklist.next, 2191da177e4SLinus Torvalds struct work_struct, entry); 2201da177e4SLinus Torvalds void (*f) (void *) = work->func; 2211da177e4SLinus Torvalds void *data = work->data; 2221da177e4SLinus Torvalds 2231da177e4SLinus Torvalds list_del_init(cwq->worklist.next); 2241da177e4SLinus Torvalds spin_unlock_irqrestore(&cwq->lock, flags); 2251da177e4SLinus Torvalds 2261da177e4SLinus Torvalds BUG_ON(work->wq_data != cwq); 2271da177e4SLinus Torvalds clear_bit(0, &work->pending); 2281da177e4SLinus Torvalds f(data); 2291da177e4SLinus Torvalds 2301da177e4SLinus Torvalds spin_lock_irqsave(&cwq->lock, flags); 2311da177e4SLinus Torvalds cwq->remove_sequence++; 2321da177e4SLinus Torvalds wake_up(&cwq->work_done); 2331da177e4SLinus Torvalds } 2341da177e4SLinus Torvalds cwq->run_depth--; 2351da177e4SLinus Torvalds spin_unlock_irqrestore(&cwq->lock, flags); 2361da177e4SLinus Torvalds } 2371da177e4SLinus Torvalds 2381da177e4SLinus Torvalds static int worker_thread(void *__cwq) 2391da177e4SLinus Torvalds { 2401da177e4SLinus Torvalds struct cpu_workqueue_struct *cwq = __cwq; 2411da177e4SLinus Torvalds DECLARE_WAITQUEUE(wait, current); 2421da177e4SLinus Torvalds struct k_sigaction sa; 2431da177e4SLinus Torvalds sigset_t blocked; 2441da177e4SLinus Torvalds 2451da177e4SLinus Torvalds current->flags |= PF_NOFREEZE; 2461da177e4SLinus Torvalds 2471da177e4SLinus Torvalds set_user_nice(current, -5); 2481da177e4SLinus Torvalds 2491da177e4SLinus Torvalds /* Block and flush all signals */ 2501da177e4SLinus Torvalds sigfillset(&blocked); 2511da177e4SLinus Torvalds sigprocmask(SIG_BLOCK, &blocked, NULL); 2521da177e4SLinus Torvalds flush_signals(current); 2531da177e4SLinus Torvalds 25446934023SChristoph Lameter /* 25546934023SChristoph Lameter * We inherited MPOL_INTERLEAVE from the booting kernel. 25646934023SChristoph Lameter * Set MPOL_DEFAULT to insure node local allocations. 25746934023SChristoph Lameter */ 25846934023SChristoph Lameter numa_default_policy(); 25946934023SChristoph Lameter 2601da177e4SLinus Torvalds /* SIG_IGN makes children autoreap: see do_notify_parent(). */ 2611da177e4SLinus Torvalds sa.sa.sa_handler = SIG_IGN; 2621da177e4SLinus Torvalds sa.sa.sa_flags = 0; 2631da177e4SLinus Torvalds siginitset(&sa.sa.sa_mask, sigmask(SIGCHLD)); 2641da177e4SLinus Torvalds do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0); 2651da177e4SLinus Torvalds 2661da177e4SLinus Torvalds set_current_state(TASK_INTERRUPTIBLE); 2671da177e4SLinus Torvalds while (!kthread_should_stop()) { 2681da177e4SLinus Torvalds add_wait_queue(&cwq->more_work, &wait); 2691da177e4SLinus Torvalds if (list_empty(&cwq->worklist)) 2701da177e4SLinus Torvalds schedule(); 2711da177e4SLinus Torvalds else 2721da177e4SLinus Torvalds __set_current_state(TASK_RUNNING); 2731da177e4SLinus Torvalds remove_wait_queue(&cwq->more_work, &wait); 2741da177e4SLinus Torvalds 2751da177e4SLinus Torvalds if (!list_empty(&cwq->worklist)) 2761da177e4SLinus Torvalds run_workqueue(cwq); 2771da177e4SLinus Torvalds set_current_state(TASK_INTERRUPTIBLE); 2781da177e4SLinus Torvalds } 2791da177e4SLinus Torvalds __set_current_state(TASK_RUNNING); 2801da177e4SLinus Torvalds return 0; 2811da177e4SLinus Torvalds } 2821da177e4SLinus Torvalds 2831da177e4SLinus Torvalds static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) 2841da177e4SLinus Torvalds { 2851da177e4SLinus Torvalds if (cwq->thread == current) { 2861da177e4SLinus Torvalds /* 2871da177e4SLinus Torvalds * Probably keventd trying to flush its own queue. So simply run 2881da177e4SLinus Torvalds * it by hand rather than deadlocking. 2891da177e4SLinus Torvalds */ 2901da177e4SLinus Torvalds run_workqueue(cwq); 2911da177e4SLinus Torvalds } else { 2921da177e4SLinus Torvalds DEFINE_WAIT(wait); 2931da177e4SLinus Torvalds long sequence_needed; 2941da177e4SLinus Torvalds 2951da177e4SLinus Torvalds spin_lock_irq(&cwq->lock); 2961da177e4SLinus Torvalds sequence_needed = cwq->insert_sequence; 2971da177e4SLinus Torvalds 2981da177e4SLinus Torvalds while (sequence_needed - cwq->remove_sequence > 0) { 2991da177e4SLinus Torvalds prepare_to_wait(&cwq->work_done, &wait, 3001da177e4SLinus Torvalds TASK_UNINTERRUPTIBLE); 3011da177e4SLinus Torvalds spin_unlock_irq(&cwq->lock); 3021da177e4SLinus Torvalds schedule(); 3031da177e4SLinus Torvalds spin_lock_irq(&cwq->lock); 3041da177e4SLinus Torvalds } 3051da177e4SLinus Torvalds finish_wait(&cwq->work_done, &wait); 3061da177e4SLinus Torvalds spin_unlock_irq(&cwq->lock); 3071da177e4SLinus Torvalds } 3081da177e4SLinus Torvalds } 3091da177e4SLinus Torvalds 3100fcb78c2SRolf Eike Beer /** 3111da177e4SLinus Torvalds * flush_workqueue - ensure that any scheduled work has run to completion. 3120fcb78c2SRolf Eike Beer * @wq: workqueue to flush 3131da177e4SLinus Torvalds * 3141da177e4SLinus Torvalds * Forces execution of the workqueue and blocks until its completion. 3151da177e4SLinus Torvalds * This is typically used in driver shutdown handlers. 3161da177e4SLinus Torvalds * 3171da177e4SLinus Torvalds * This function will sample each workqueue's current insert_sequence number and 3181da177e4SLinus Torvalds * will sleep until the head sequence is greater than or equal to that. This 3191da177e4SLinus Torvalds * means that we sleep until all works which were queued on entry have been 3201da177e4SLinus Torvalds * handled, but we are not livelocked by new incoming ones. 3211da177e4SLinus Torvalds * 3221da177e4SLinus Torvalds * This function used to run the workqueues itself. Now we just wait for the 3231da177e4SLinus Torvalds * helper threads to do it. 3241da177e4SLinus Torvalds */ 3251da177e4SLinus Torvalds void fastcall flush_workqueue(struct workqueue_struct *wq) 3261da177e4SLinus Torvalds { 3271da177e4SLinus Torvalds might_sleep(); 3281da177e4SLinus Torvalds 3291da177e4SLinus Torvalds if (is_single_threaded(wq)) { 330bce61dd4SBen Collins /* Always use first cpu's area. */ 331f756d5e2SNathan Lynch flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, singlethread_cpu)); 3321da177e4SLinus Torvalds } else { 3331da177e4SLinus Torvalds int cpu; 3341da177e4SLinus Torvalds 3359b41ea72SAndrew Morton mutex_lock(&workqueue_mutex); 3361da177e4SLinus Torvalds for_each_online_cpu(cpu) 33789ada679SChristoph Lameter flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); 3389b41ea72SAndrew Morton mutex_unlock(&workqueue_mutex); 3391da177e4SLinus Torvalds } 3401da177e4SLinus Torvalds } 341ae90dd5dSDave Jones EXPORT_SYMBOL_GPL(flush_workqueue); 3421da177e4SLinus Torvalds 3431da177e4SLinus Torvalds static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq, 3441da177e4SLinus Torvalds int cpu) 3451da177e4SLinus Torvalds { 34689ada679SChristoph Lameter struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); 3471da177e4SLinus Torvalds struct task_struct *p; 3481da177e4SLinus Torvalds 3491da177e4SLinus Torvalds spin_lock_init(&cwq->lock); 3501da177e4SLinus Torvalds cwq->wq = wq; 3511da177e4SLinus Torvalds cwq->thread = NULL; 3521da177e4SLinus Torvalds cwq->insert_sequence = 0; 3531da177e4SLinus Torvalds cwq->remove_sequence = 0; 3541da177e4SLinus Torvalds INIT_LIST_HEAD(&cwq->worklist); 3551da177e4SLinus Torvalds init_waitqueue_head(&cwq->more_work); 3561da177e4SLinus Torvalds init_waitqueue_head(&cwq->work_done); 3571da177e4SLinus Torvalds 3581da177e4SLinus Torvalds if (is_single_threaded(wq)) 3591da177e4SLinus Torvalds p = kthread_create(worker_thread, cwq, "%s", wq->name); 3601da177e4SLinus Torvalds else 3611da177e4SLinus Torvalds p = kthread_create(worker_thread, cwq, "%s/%d", wq->name, cpu); 3621da177e4SLinus Torvalds if (IS_ERR(p)) 3631da177e4SLinus Torvalds return NULL; 3641da177e4SLinus Torvalds cwq->thread = p; 3651da177e4SLinus Torvalds return p; 3661da177e4SLinus Torvalds } 3671da177e4SLinus Torvalds 3681da177e4SLinus Torvalds struct workqueue_struct *__create_workqueue(const char *name, 3691da177e4SLinus Torvalds int singlethread) 3701da177e4SLinus Torvalds { 3711da177e4SLinus Torvalds int cpu, destroy = 0; 3721da177e4SLinus Torvalds struct workqueue_struct *wq; 3731da177e4SLinus Torvalds struct task_struct *p; 3741da177e4SLinus Torvalds 375dd392710SPekka J Enberg wq = kzalloc(sizeof(*wq), GFP_KERNEL); 3761da177e4SLinus Torvalds if (!wq) 3771da177e4SLinus Torvalds return NULL; 3781da177e4SLinus Torvalds 37989ada679SChristoph Lameter wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct); 380676121fcSBen Collins if (!wq->cpu_wq) { 381676121fcSBen Collins kfree(wq); 382676121fcSBen Collins return NULL; 383676121fcSBen Collins } 384676121fcSBen Collins 3851da177e4SLinus Torvalds wq->name = name; 3869b41ea72SAndrew Morton mutex_lock(&workqueue_mutex); 3871da177e4SLinus Torvalds if (singlethread) { 3881da177e4SLinus Torvalds INIT_LIST_HEAD(&wq->list); 389f756d5e2SNathan Lynch p = create_workqueue_thread(wq, singlethread_cpu); 3901da177e4SLinus Torvalds if (!p) 3911da177e4SLinus Torvalds destroy = 1; 3921da177e4SLinus Torvalds else 3931da177e4SLinus Torvalds wake_up_process(p); 3941da177e4SLinus Torvalds } else { 3951da177e4SLinus Torvalds list_add(&wq->list, &workqueues); 3961da177e4SLinus Torvalds for_each_online_cpu(cpu) { 3971da177e4SLinus Torvalds p = create_workqueue_thread(wq, cpu); 3981da177e4SLinus Torvalds if (p) { 3991da177e4SLinus Torvalds kthread_bind(p, cpu); 4001da177e4SLinus Torvalds wake_up_process(p); 4011da177e4SLinus Torvalds } else 4021da177e4SLinus Torvalds destroy = 1; 4031da177e4SLinus Torvalds } 4041da177e4SLinus Torvalds } 4059b41ea72SAndrew Morton mutex_unlock(&workqueue_mutex); 4061da177e4SLinus Torvalds 4071da177e4SLinus Torvalds /* 4081da177e4SLinus Torvalds * Was there any error during startup? If yes then clean up: 4091da177e4SLinus Torvalds */ 4101da177e4SLinus Torvalds if (destroy) { 4111da177e4SLinus Torvalds destroy_workqueue(wq); 4121da177e4SLinus Torvalds wq = NULL; 4131da177e4SLinus Torvalds } 4141da177e4SLinus Torvalds return wq; 4151da177e4SLinus Torvalds } 416ae90dd5dSDave Jones EXPORT_SYMBOL_GPL(__create_workqueue); 4171da177e4SLinus Torvalds 4181da177e4SLinus Torvalds static void cleanup_workqueue_thread(struct workqueue_struct *wq, int cpu) 4191da177e4SLinus Torvalds { 4201da177e4SLinus Torvalds struct cpu_workqueue_struct *cwq; 4211da177e4SLinus Torvalds unsigned long flags; 4221da177e4SLinus Torvalds struct task_struct *p; 4231da177e4SLinus Torvalds 42489ada679SChristoph Lameter cwq = per_cpu_ptr(wq->cpu_wq, cpu); 4251da177e4SLinus Torvalds spin_lock_irqsave(&cwq->lock, flags); 4261da177e4SLinus Torvalds p = cwq->thread; 4271da177e4SLinus Torvalds cwq->thread = NULL; 4281da177e4SLinus Torvalds spin_unlock_irqrestore(&cwq->lock, flags); 4291da177e4SLinus Torvalds if (p) 4301da177e4SLinus Torvalds kthread_stop(p); 4311da177e4SLinus Torvalds } 4321da177e4SLinus Torvalds 4330fcb78c2SRolf Eike Beer /** 4340fcb78c2SRolf Eike Beer * destroy_workqueue - safely terminate a workqueue 4350fcb78c2SRolf Eike Beer * @wq: target workqueue 4360fcb78c2SRolf Eike Beer * 4370fcb78c2SRolf Eike Beer * Safely destroy a workqueue. All work currently pending will be done first. 4380fcb78c2SRolf Eike Beer */ 4391da177e4SLinus Torvalds void destroy_workqueue(struct workqueue_struct *wq) 4401da177e4SLinus Torvalds { 4411da177e4SLinus Torvalds int cpu; 4421da177e4SLinus Torvalds 4431da177e4SLinus Torvalds flush_workqueue(wq); 4441da177e4SLinus Torvalds 4451da177e4SLinus Torvalds /* We don't need the distraction of CPUs appearing and vanishing. */ 4469b41ea72SAndrew Morton mutex_lock(&workqueue_mutex); 4471da177e4SLinus Torvalds if (is_single_threaded(wq)) 448f756d5e2SNathan Lynch cleanup_workqueue_thread(wq, singlethread_cpu); 4491da177e4SLinus Torvalds else { 4501da177e4SLinus Torvalds for_each_online_cpu(cpu) 4511da177e4SLinus Torvalds cleanup_workqueue_thread(wq, cpu); 4521da177e4SLinus Torvalds list_del(&wq->list); 4531da177e4SLinus Torvalds } 4549b41ea72SAndrew Morton mutex_unlock(&workqueue_mutex); 45589ada679SChristoph Lameter free_percpu(wq->cpu_wq); 4561da177e4SLinus Torvalds kfree(wq); 4571da177e4SLinus Torvalds } 458ae90dd5dSDave Jones EXPORT_SYMBOL_GPL(destroy_workqueue); 4591da177e4SLinus Torvalds 4601da177e4SLinus Torvalds static struct workqueue_struct *keventd_wq; 4611da177e4SLinus Torvalds 4620fcb78c2SRolf Eike Beer /** 4630fcb78c2SRolf Eike Beer * schedule_work - put work task in global workqueue 4640fcb78c2SRolf Eike Beer * @work: job to be done 4650fcb78c2SRolf Eike Beer * 4660fcb78c2SRolf Eike Beer * This puts a job in the kernel-global workqueue. 4670fcb78c2SRolf Eike Beer */ 4681da177e4SLinus Torvalds int fastcall schedule_work(struct work_struct *work) 4691da177e4SLinus Torvalds { 4701da177e4SLinus Torvalds return queue_work(keventd_wq, work); 4711da177e4SLinus Torvalds } 472ae90dd5dSDave Jones EXPORT_SYMBOL(schedule_work); 4731da177e4SLinus Torvalds 4740fcb78c2SRolf Eike Beer /** 4750fcb78c2SRolf Eike Beer * schedule_delayed_work - put work task in global workqueue after delay 47652bad64dSDavid Howells * @dwork: job to be done 47752bad64dSDavid Howells * @delay: number of jiffies to wait or 0 for immediate execution 4780fcb78c2SRolf Eike Beer * 4790fcb78c2SRolf Eike Beer * After waiting for a given time this puts a job in the kernel-global 4800fcb78c2SRolf Eike Beer * workqueue. 4810fcb78c2SRolf Eike Beer */ 48252bad64dSDavid Howells int fastcall schedule_delayed_work(struct delayed_work *dwork, unsigned long delay) 4831da177e4SLinus Torvalds { 48452bad64dSDavid Howells return queue_delayed_work(keventd_wq, dwork, delay); 4851da177e4SLinus Torvalds } 486ae90dd5dSDave Jones EXPORT_SYMBOL(schedule_delayed_work); 4871da177e4SLinus Torvalds 4880fcb78c2SRolf Eike Beer /** 4890fcb78c2SRolf Eike Beer * schedule_delayed_work_on - queue work in global workqueue on CPU after delay 4900fcb78c2SRolf Eike Beer * @cpu: cpu to use 49152bad64dSDavid Howells * @dwork: job to be done 4920fcb78c2SRolf Eike Beer * @delay: number of jiffies to wait 4930fcb78c2SRolf Eike Beer * 4940fcb78c2SRolf Eike Beer * After waiting for a given time this puts a job in the kernel-global 4950fcb78c2SRolf Eike Beer * workqueue on the specified CPU. 4960fcb78c2SRolf Eike Beer */ 4971da177e4SLinus Torvalds int schedule_delayed_work_on(int cpu, 49852bad64dSDavid Howells struct delayed_work *dwork, unsigned long delay) 4991da177e4SLinus Torvalds { 50052bad64dSDavid Howells return queue_delayed_work_on(cpu, keventd_wq, dwork, delay); 5011da177e4SLinus Torvalds } 502ae90dd5dSDave Jones EXPORT_SYMBOL(schedule_delayed_work_on); 5031da177e4SLinus Torvalds 504b6136773SAndrew Morton /** 505b6136773SAndrew Morton * schedule_on_each_cpu - call a function on each online CPU from keventd 506b6136773SAndrew Morton * @func: the function to call 507b6136773SAndrew Morton * @info: a pointer to pass to func() 508b6136773SAndrew Morton * 509b6136773SAndrew Morton * Returns zero on success. 510b6136773SAndrew Morton * Returns -ve errno on failure. 511b6136773SAndrew Morton * 512b6136773SAndrew Morton * Appears to be racy against CPU hotplug. 513b6136773SAndrew Morton * 514b6136773SAndrew Morton * schedule_on_each_cpu() is very slow. 515b6136773SAndrew Morton */ 51615316ba8SChristoph Lameter int schedule_on_each_cpu(void (*func)(void *info), void *info) 51715316ba8SChristoph Lameter { 51815316ba8SChristoph Lameter int cpu; 519b6136773SAndrew Morton struct work_struct *works; 52015316ba8SChristoph Lameter 521b6136773SAndrew Morton works = alloc_percpu(struct work_struct); 522b6136773SAndrew Morton if (!works) 52315316ba8SChristoph Lameter return -ENOMEM; 524b6136773SAndrew Morton 5259b41ea72SAndrew Morton mutex_lock(&workqueue_mutex); 52615316ba8SChristoph Lameter for_each_online_cpu(cpu) { 527b6136773SAndrew Morton INIT_WORK(per_cpu_ptr(works, cpu), func, info); 52815316ba8SChristoph Lameter __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), 529b6136773SAndrew Morton per_cpu_ptr(works, cpu)); 53015316ba8SChristoph Lameter } 5319b41ea72SAndrew Morton mutex_unlock(&workqueue_mutex); 53215316ba8SChristoph Lameter flush_workqueue(keventd_wq); 533b6136773SAndrew Morton free_percpu(works); 53415316ba8SChristoph Lameter return 0; 53515316ba8SChristoph Lameter } 53615316ba8SChristoph Lameter 5371da177e4SLinus Torvalds void flush_scheduled_work(void) 5381da177e4SLinus Torvalds { 5391da177e4SLinus Torvalds flush_workqueue(keventd_wq); 5401da177e4SLinus Torvalds } 541ae90dd5dSDave Jones EXPORT_SYMBOL(flush_scheduled_work); 5421da177e4SLinus Torvalds 5431da177e4SLinus Torvalds /** 5441da177e4SLinus Torvalds * cancel_rearming_delayed_workqueue - reliably kill off a delayed 5451da177e4SLinus Torvalds * work whose handler rearms the delayed work. 5461da177e4SLinus Torvalds * @wq: the controlling workqueue structure 54752bad64dSDavid Howells * @dwork: the delayed work struct 5481da177e4SLinus Torvalds */ 54981ddef77SJames Bottomley void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq, 55052bad64dSDavid Howells struct delayed_work *dwork) 5511da177e4SLinus Torvalds { 55252bad64dSDavid Howells while (!cancel_delayed_work(dwork)) 5531da177e4SLinus Torvalds flush_workqueue(wq); 5541da177e4SLinus Torvalds } 55581ddef77SJames Bottomley EXPORT_SYMBOL(cancel_rearming_delayed_workqueue); 5561da177e4SLinus Torvalds 5571da177e4SLinus Torvalds /** 5581da177e4SLinus Torvalds * cancel_rearming_delayed_work - reliably kill off a delayed keventd 5591da177e4SLinus Torvalds * work whose handler rearms the delayed work. 56052bad64dSDavid Howells * @dwork: the delayed work struct 5611da177e4SLinus Torvalds */ 56252bad64dSDavid Howells void cancel_rearming_delayed_work(struct delayed_work *dwork) 5631da177e4SLinus Torvalds { 56452bad64dSDavid Howells cancel_rearming_delayed_workqueue(keventd_wq, dwork); 5651da177e4SLinus Torvalds } 5661da177e4SLinus Torvalds EXPORT_SYMBOL(cancel_rearming_delayed_work); 5671da177e4SLinus Torvalds 5681fa44ecaSJames Bottomley /** 5691fa44ecaSJames Bottomley * execute_in_process_context - reliably execute the routine with user context 5701fa44ecaSJames Bottomley * @fn: the function to execute 5711fa44ecaSJames Bottomley * @data: data to pass to the function 5721fa44ecaSJames Bottomley * @ew: guaranteed storage for the execute work structure (must 5731fa44ecaSJames Bottomley * be available when the work executes) 5741fa44ecaSJames Bottomley * 5751fa44ecaSJames Bottomley * Executes the function immediately if process context is available, 5761fa44ecaSJames Bottomley * otherwise schedules the function for delayed execution. 5771fa44ecaSJames Bottomley * 5781fa44ecaSJames Bottomley * Returns: 0 - function was executed 5791fa44ecaSJames Bottomley * 1 - function was scheduled for execution 5801fa44ecaSJames Bottomley */ 5811fa44ecaSJames Bottomley int execute_in_process_context(void (*fn)(void *data), void *data, 5821fa44ecaSJames Bottomley struct execute_work *ew) 5831fa44ecaSJames Bottomley { 5841fa44ecaSJames Bottomley if (!in_interrupt()) { 5851fa44ecaSJames Bottomley fn(data); 5861fa44ecaSJames Bottomley return 0; 5871fa44ecaSJames Bottomley } 5881fa44ecaSJames Bottomley 5891fa44ecaSJames Bottomley INIT_WORK(&ew->work, fn, data); 5901fa44ecaSJames Bottomley schedule_work(&ew->work); 5911fa44ecaSJames Bottomley 5921fa44ecaSJames Bottomley return 1; 5931fa44ecaSJames Bottomley } 5941fa44ecaSJames Bottomley EXPORT_SYMBOL_GPL(execute_in_process_context); 5951fa44ecaSJames Bottomley 5961da177e4SLinus Torvalds int keventd_up(void) 5971da177e4SLinus Torvalds { 5981da177e4SLinus Torvalds return keventd_wq != NULL; 5991da177e4SLinus Torvalds } 6001da177e4SLinus Torvalds 6011da177e4SLinus Torvalds int current_is_keventd(void) 6021da177e4SLinus Torvalds { 6031da177e4SLinus Torvalds struct cpu_workqueue_struct *cwq; 6041da177e4SLinus Torvalds int cpu = smp_processor_id(); /* preempt-safe: keventd is per-cpu */ 6051da177e4SLinus Torvalds int ret = 0; 6061da177e4SLinus Torvalds 6071da177e4SLinus Torvalds BUG_ON(!keventd_wq); 6081da177e4SLinus Torvalds 60989ada679SChristoph Lameter cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu); 6101da177e4SLinus Torvalds if (current == cwq->thread) 6111da177e4SLinus Torvalds ret = 1; 6121da177e4SLinus Torvalds 6131da177e4SLinus Torvalds return ret; 6141da177e4SLinus Torvalds 6151da177e4SLinus Torvalds } 6161da177e4SLinus Torvalds 6171da177e4SLinus Torvalds #ifdef CONFIG_HOTPLUG_CPU 6181da177e4SLinus Torvalds /* Take the work from this (downed) CPU. */ 6191da177e4SLinus Torvalds static void take_over_work(struct workqueue_struct *wq, unsigned int cpu) 6201da177e4SLinus Torvalds { 62189ada679SChristoph Lameter struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); 622626ab0e6SOleg Nesterov struct list_head list; 6231da177e4SLinus Torvalds struct work_struct *work; 6241da177e4SLinus Torvalds 6251da177e4SLinus Torvalds spin_lock_irq(&cwq->lock); 626626ab0e6SOleg Nesterov list_replace_init(&cwq->worklist, &list); 6271da177e4SLinus Torvalds 6281da177e4SLinus Torvalds while (!list_empty(&list)) { 6291da177e4SLinus Torvalds printk("Taking work for %s\n", wq->name); 6301da177e4SLinus Torvalds work = list_entry(list.next,struct work_struct,entry); 6311da177e4SLinus Torvalds list_del(&work->entry); 63289ada679SChristoph Lameter __queue_work(per_cpu_ptr(wq->cpu_wq, smp_processor_id()), work); 6331da177e4SLinus Torvalds } 6341da177e4SLinus Torvalds spin_unlock_irq(&cwq->lock); 6351da177e4SLinus Torvalds } 6361da177e4SLinus Torvalds 6371da177e4SLinus Torvalds /* We're holding the cpucontrol mutex here */ 6389c7b216dSChandra Seetharaman static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, 6391da177e4SLinus Torvalds unsigned long action, 6401da177e4SLinus Torvalds void *hcpu) 6411da177e4SLinus Torvalds { 6421da177e4SLinus Torvalds unsigned int hotcpu = (unsigned long)hcpu; 6431da177e4SLinus Torvalds struct workqueue_struct *wq; 6441da177e4SLinus Torvalds 6451da177e4SLinus Torvalds switch (action) { 6461da177e4SLinus Torvalds case CPU_UP_PREPARE: 6479b41ea72SAndrew Morton mutex_lock(&workqueue_mutex); 6481da177e4SLinus Torvalds /* Create a new workqueue thread for it. */ 6491da177e4SLinus Torvalds list_for_each_entry(wq, &workqueues, list) { 650230649daSMika Kukkonen if (!create_workqueue_thread(wq, hotcpu)) { 6511da177e4SLinus Torvalds printk("workqueue for %i failed\n", hotcpu); 6521da177e4SLinus Torvalds return NOTIFY_BAD; 6531da177e4SLinus Torvalds } 6541da177e4SLinus Torvalds } 6551da177e4SLinus Torvalds break; 6561da177e4SLinus Torvalds 6571da177e4SLinus Torvalds case CPU_ONLINE: 6581da177e4SLinus Torvalds /* Kick off worker threads. */ 6591da177e4SLinus Torvalds list_for_each_entry(wq, &workqueues, list) { 66089ada679SChristoph Lameter struct cpu_workqueue_struct *cwq; 66189ada679SChristoph Lameter 66289ada679SChristoph Lameter cwq = per_cpu_ptr(wq->cpu_wq, hotcpu); 66389ada679SChristoph Lameter kthread_bind(cwq->thread, hotcpu); 66489ada679SChristoph Lameter wake_up_process(cwq->thread); 6651da177e4SLinus Torvalds } 6669b41ea72SAndrew Morton mutex_unlock(&workqueue_mutex); 6671da177e4SLinus Torvalds break; 6681da177e4SLinus Torvalds 6691da177e4SLinus Torvalds case CPU_UP_CANCELED: 6701da177e4SLinus Torvalds list_for_each_entry(wq, &workqueues, list) { 671fc75cdfaSHeiko Carstens if (!per_cpu_ptr(wq->cpu_wq, hotcpu)->thread) 672fc75cdfaSHeiko Carstens continue; 6731da177e4SLinus Torvalds /* Unbind so it can run. */ 67489ada679SChristoph Lameter kthread_bind(per_cpu_ptr(wq->cpu_wq, hotcpu)->thread, 675a4c4af7cSHeiko Carstens any_online_cpu(cpu_online_map)); 6761da177e4SLinus Torvalds cleanup_workqueue_thread(wq, hotcpu); 6771da177e4SLinus Torvalds } 6789b41ea72SAndrew Morton mutex_unlock(&workqueue_mutex); 6799b41ea72SAndrew Morton break; 6809b41ea72SAndrew Morton 6819b41ea72SAndrew Morton case CPU_DOWN_PREPARE: 6829b41ea72SAndrew Morton mutex_lock(&workqueue_mutex); 6839b41ea72SAndrew Morton break; 6849b41ea72SAndrew Morton 6859b41ea72SAndrew Morton case CPU_DOWN_FAILED: 6869b41ea72SAndrew Morton mutex_unlock(&workqueue_mutex); 6871da177e4SLinus Torvalds break; 6881da177e4SLinus Torvalds 6891da177e4SLinus Torvalds case CPU_DEAD: 6901da177e4SLinus Torvalds list_for_each_entry(wq, &workqueues, list) 6911da177e4SLinus Torvalds cleanup_workqueue_thread(wq, hotcpu); 6921da177e4SLinus Torvalds list_for_each_entry(wq, &workqueues, list) 6931da177e4SLinus Torvalds take_over_work(wq, hotcpu); 6949b41ea72SAndrew Morton mutex_unlock(&workqueue_mutex); 6951da177e4SLinus Torvalds break; 6961da177e4SLinus Torvalds } 6971da177e4SLinus Torvalds 6981da177e4SLinus Torvalds return NOTIFY_OK; 6991da177e4SLinus Torvalds } 7001da177e4SLinus Torvalds #endif 7011da177e4SLinus Torvalds 7021da177e4SLinus Torvalds void init_workqueues(void) 7031da177e4SLinus Torvalds { 704f756d5e2SNathan Lynch singlethread_cpu = first_cpu(cpu_possible_map); 7051da177e4SLinus Torvalds hotcpu_notifier(workqueue_cpu_callback, 0); 7061da177e4SLinus Torvalds keventd_wq = create_workqueue("events"); 7071da177e4SLinus Torvalds BUG_ON(!keventd_wq); 7081da177e4SLinus Torvalds } 7091da177e4SLinus Torvalds 710