X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=kernel%2Fworkqueue.c;fp=kernel%2Fworkqueue.c;h=a3da07c5af2835f57f094cddd20e731a8a77bdb5;hb=97bf2856c6014879bd04983a3e9dfcdac1e7fe85;hp=b052e2c4c71053720e87606e20924cfec5f3f27c;hpb=76828883507a47dae78837ab5dec5a5b4513c667;p=linux-2.6.git diff --git a/kernel/workqueue.c b/kernel/workqueue.c index b052e2c4c..a3da07c5a 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -27,13 +27,18 @@ #include #include #include +#include +#include +#include +#include +#include /* * The per-CPU workqueue (if single thread, we always use the first * possible cpu). * * The sequence counters are for flush_scheduled_work(). It wants to wait - * until until all currently-scheduled works are completed, but it doesn't + * until all currently-scheduled works are completed, but it doesn't * want to be livelocked by new, incoming ones. So it waits until * remove_sequence is >= the insert_sequence which pertained when * flush_scheduled_work() was called. @@ -50,9 +55,11 @@ struct cpu_workqueue_struct { wait_queue_head_t work_done; struct workqueue_struct *wq; - task_t *thread; + struct task_struct *thread; int run_depth; /* Detect run_workqueue() recursion depth */ + + int freezeable; /* Freeze the thread during suspend */ } ____cacheline_aligned; /* @@ -67,7 +74,7 @@ struct workqueue_struct { /* All the per-cpu workqueues on the system, for hotplug cpu to add/remove threads to each one as cpus come/go. */ -static DEFINE_SPINLOCK(workqueue_lock); +static DEFINE_MUTEX(workqueue_mutex); static LIST_HEAD(workqueues); static int singlethread_cpu; @@ -78,6 +85,99 @@ static inline int is_single_threaded(struct workqueue_struct *wq) return list_empty(&wq->list); } +/* + * Set the workqueue on which a work item is to be run + * - Must *only* be called if the pending flag is set + */ +static inline void set_wq_data(struct work_struct *work, void *wq) +{ + unsigned long new; + + BUG_ON(!work_pending(work)); + + new = (unsigned long) wq | (1UL << WORK_STRUCT_PENDING); + new |= WORK_STRUCT_FLAG_MASK & *work_data_bits(work); + atomic_long_set(&work->data, new); +} + +static inline void *get_wq_data(struct work_struct *work) +{ + return (void *) (atomic_long_read(&work->data) & WORK_STRUCT_WQ_DATA_MASK); +} + +static int __run_work(struct cpu_workqueue_struct *cwq, struct work_struct *work) +{ + int ret = 0; + unsigned long flags; + + spin_lock_irqsave(&cwq->lock, flags); + /* + * We need to re-validate the work info after we've gotten + * the cpu_workqueue lock. We can run the work now iff: + * + * - the wq_data still matches the cpu_workqueue_struct + * - AND the work is still marked pending + * - AND the work is still on a list (which will be this + * workqueue_struct list) + * + * All these conditions are important, because we + * need to protect against the work being run right + * now on another CPU (all but the last one might be + * true if it's currently running and has not been + * released yet, for example). + */ + if (get_wq_data(work) == cwq + && work_pending(work) + && !list_empty(&work->entry)) { + work_func_t f = work->func; + list_del_init(&work->entry); + spin_unlock_irqrestore(&cwq->lock, flags); + + if (!test_bit(WORK_STRUCT_NOAUTOREL, work_data_bits(work))) + work_release(work); + f(work); + + spin_lock_irqsave(&cwq->lock, flags); + cwq->remove_sequence++; + wake_up(&cwq->work_done); + ret = 1; + } + spin_unlock_irqrestore(&cwq->lock, flags); + return ret; +} + +/** + * run_scheduled_work - run scheduled work synchronously + * @work: work to run + * + * This checks if the work was pending, and runs it + * synchronously if so. It returns a boolean to indicate + * whether it had any scheduled work to run or not. + * + * NOTE! This _only_ works for normal work_structs. You + * CANNOT use this for delayed work, because the wq data + * for delayed work will not point properly to the per- + * CPU workqueue struct, but will change! + */ +int fastcall run_scheduled_work(struct work_struct *work) +{ + for (;;) { + struct cpu_workqueue_struct *cwq; + + if (!work_pending(work)) + return 0; + if (list_empty(&work->entry)) + return 0; + /* NOTE! This depends intimately on __queue_work! */ + cwq = get_wq_data(work); + if (!cwq) + return 0; + if (__run_work(cwq, work)) + return 1; + } +} +EXPORT_SYMBOL(run_scheduled_work); + /* Preempt must be disabled. */ static void __queue_work(struct cpu_workqueue_struct *cwq, struct work_struct *work) @@ -85,16 +185,19 @@ static void __queue_work(struct cpu_workqueue_struct *cwq, unsigned long flags; spin_lock_irqsave(&cwq->lock, flags); - work->wq_data = cwq; + set_wq_data(work, cwq); list_add_tail(&work->entry, &cwq->worklist); cwq->insert_sequence++; wake_up(&cwq->more_work); spin_unlock_irqrestore(&cwq->lock, flags); } -/* - * Queue work on a workqueue. Return non-zero if it was successfully - * added. +/** + * queue_work - queue work on a workqueue + * @wq: workqueue to use + * @work: work to queue + * + * Returns 0 if @work was already on a queue, non-zero otherwise. * * We queue the work to the CPU it was submitted, but there is no * guarantee that it will be processed by that CPU. @@ -103,7 +206,7 @@ int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work) { int ret = 0, cpu = get_cpu(); - if (!test_and_set_bit(0, &work->pending)) { + if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { if (unlikely(is_single_threaded(wq))) cpu = singlethread_cpu; BUG_ON(!list_empty(&work->entry)); @@ -113,39 +216,85 @@ int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work) put_cpu(); return ret; } +EXPORT_SYMBOL_GPL(queue_work); static void delayed_work_timer_fn(unsigned long __data) { - struct work_struct *work = (struct work_struct *)__data; - struct workqueue_struct *wq = work->wq_data; + struct delayed_work *dwork = (struct delayed_work *)__data; + struct workqueue_struct *wq = get_wq_data(&dwork->work); int cpu = smp_processor_id(); if (unlikely(is_single_threaded(wq))) cpu = singlethread_cpu; - __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work); + __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), &dwork->work); } +/** + * queue_delayed_work - queue work on a workqueue after delay + * @wq: workqueue to use + * @dwork: delayable work to queue + * @delay: number of jiffies to wait before queueing + * + * Returns 0 if @work was already on a queue, non-zero otherwise. + */ int fastcall queue_delayed_work(struct workqueue_struct *wq, - struct work_struct *work, unsigned long delay) + struct delayed_work *dwork, unsigned long delay) { int ret = 0; - struct timer_list *timer = &work->timer; + struct timer_list *timer = &dwork->timer; + struct work_struct *work = &dwork->work; - if (!test_and_set_bit(0, &work->pending)) { + if (delay == 0) + return queue_work(wq, work); + + if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { BUG_ON(timer_pending(timer)); BUG_ON(!list_empty(&work->entry)); /* This stores wq for the moment, for the timer_fn */ - work->wq_data = wq; + set_wq_data(work, wq); timer->expires = jiffies + delay; - timer->data = (unsigned long)work; + timer->data = (unsigned long)dwork; timer->function = delayed_work_timer_fn; add_timer(timer); ret = 1; } return ret; } +EXPORT_SYMBOL_GPL(queue_delayed_work); + +/** + * queue_delayed_work_on - queue work on specific CPU after delay + * @cpu: CPU number to execute work on + * @wq: workqueue to use + * @dwork: work to queue + * @delay: number of jiffies to wait before queueing + * + * Returns 0 if @work was already on a queue, non-zero otherwise. + */ +int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, + struct delayed_work *dwork, unsigned long delay) +{ + int ret = 0; + struct timer_list *timer = &dwork->timer; + struct work_struct *work = &dwork->work; + + if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) { + BUG_ON(timer_pending(timer)); + BUG_ON(!list_empty(&work->entry)); + + /* This stores wq for the moment, for the timer_fn */ + set_wq_data(work, wq); + timer->expires = jiffies + delay; + timer->data = (unsigned long)dwork; + timer->function = delayed_work_timer_fn; + add_timer_on(timer, cpu); + ret = 1; + } + return ret; +} +EXPORT_SYMBOL_GPL(queue_delayed_work_on); static void run_workqueue(struct cpu_workqueue_struct *cwq) { @@ -166,15 +315,26 @@ static void run_workqueue(struct cpu_workqueue_struct *cwq) while (!list_empty(&cwq->worklist)) { struct work_struct *work = list_entry(cwq->worklist.next, struct work_struct, entry); - void (*f) (void *) = work->func; - void *data = work->data; + work_func_t f = work->func; list_del_init(cwq->worklist.next); spin_unlock_irqrestore(&cwq->lock, flags); - BUG_ON(work->wq_data != cwq); - clear_bit(0, &work->pending); - f(data); + BUG_ON(get_wq_data(work) != cwq); + if (!test_bit(WORK_STRUCT_NOAUTOREL, work_data_bits(work))) + work_release(work); + f(work); + + if (unlikely(in_atomic() || lockdep_depth(current) > 0)) { + printk(KERN_ERR "BUG: workqueue leaked lock or atomic: " + "%s/0x%08x/%d\n", + current->comm, preempt_count(), + current->pid); + printk(KERN_ERR " last function: "); + print_symbol("%s\n", (unsigned long)f); + debug_show_held_locks(current); + dump_stack(); + } spin_lock_irqsave(&cwq->lock, flags); cwq->remove_sequence++; @@ -191,7 +351,8 @@ static int worker_thread(void *__cwq) struct k_sigaction sa; sigset_t blocked; - current->flags |= PF_NOFREEZE; + if (!cwq->freezeable) + current->flags |= PF_NOFREEZE; set_user_nice(current, -5); @@ -200,6 +361,12 @@ static int worker_thread(void *__cwq) sigprocmask(SIG_BLOCK, &blocked, NULL); flush_signals(current); + /* + * We inherited MPOL_INTERLEAVE from the booting kernel. + * Set MPOL_DEFAULT to insure node local allocations. + */ + numa_default_policy(); + /* SIG_IGN makes children autoreap: see do_notify_parent(). */ sa.sa.sa_handler = SIG_IGN; sa.sa.sa_flags = 0; @@ -208,6 +375,9 @@ static int worker_thread(void *__cwq) set_current_state(TASK_INTERRUPTIBLE); while (!kthread_should_stop()) { + if (cwq->freezeable) + try_to_freeze(); + add_wait_queue(&cwq->more_work, &wait); if (list_empty(&cwq->worklist)) schedule(); @@ -250,8 +420,9 @@ static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) } } -/* +/** * flush_workqueue - ensure that any scheduled work has run to completion. + * @wq: workqueue to flush * * Forces execution of the workqueue and blocks until its completion. * This is typically used in driver shutdown handlers. @@ -274,15 +445,16 @@ void fastcall flush_workqueue(struct workqueue_struct *wq) } else { int cpu; - lock_cpu_hotplug(); + mutex_lock(&workqueue_mutex); for_each_online_cpu(cpu) flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); - unlock_cpu_hotplug(); + mutex_unlock(&workqueue_mutex); } } +EXPORT_SYMBOL_GPL(flush_workqueue); static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq, - int cpu) + int cpu, int freezeable) { struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); struct task_struct *p; @@ -292,6 +464,7 @@ static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq, cwq->thread = NULL; cwq->insert_sequence = 0; cwq->remove_sequence = 0; + cwq->freezeable = freezeable; INIT_LIST_HEAD(&cwq->worklist); init_waitqueue_head(&cwq->more_work); init_waitqueue_head(&cwq->work_done); @@ -307,7 +480,7 @@ static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq, } struct workqueue_struct *__create_workqueue(const char *name, - int singlethread) + int singlethread, int freezeable) { int cpu, destroy = 0; struct workqueue_struct *wq; @@ -324,21 +497,18 @@ struct workqueue_struct *__create_workqueue(const char *name, } wq->name = name; - /* We don't need the distraction of CPUs appearing and vanishing. */ - lock_cpu_hotplug(); + mutex_lock(&workqueue_mutex); if (singlethread) { INIT_LIST_HEAD(&wq->list); - p = create_workqueue_thread(wq, singlethread_cpu); + p = create_workqueue_thread(wq, singlethread_cpu, freezeable); if (!p) destroy = 1; else wake_up_process(p); } else { - spin_lock(&workqueue_lock); list_add(&wq->list, &workqueues); - spin_unlock(&workqueue_lock); for_each_online_cpu(cpu) { - p = create_workqueue_thread(wq, cpu); + p = create_workqueue_thread(wq, cpu, freezeable); if (p) { kthread_bind(p, cpu); wake_up_process(p); @@ -346,7 +516,7 @@ struct workqueue_struct *__create_workqueue(const char *name, destroy = 1; } } - unlock_cpu_hotplug(); + mutex_unlock(&workqueue_mutex); /* * Was there any error during startup? If yes then clean up: @@ -357,6 +527,7 @@ struct workqueue_struct *__create_workqueue(const char *name, } return wq; } +EXPORT_SYMBOL_GPL(__create_workqueue); static void cleanup_workqueue_thread(struct workqueue_struct *wq, int cpu) { @@ -373,6 +544,12 @@ static void cleanup_workqueue_thread(struct workqueue_struct *wq, int cpu) kthread_stop(p); } +/** + * destroy_workqueue - safely terminate a workqueue + * @wq: target workqueue + * + * Safely destroy a workqueue. All work currently pending will be done first. + */ void destroy_workqueue(struct workqueue_struct *wq) { int cpu; @@ -380,69 +557,95 @@ void destroy_workqueue(struct workqueue_struct *wq) flush_workqueue(wq); /* We don't need the distraction of CPUs appearing and vanishing. */ - lock_cpu_hotplug(); + mutex_lock(&workqueue_mutex); if (is_single_threaded(wq)) cleanup_workqueue_thread(wq, singlethread_cpu); else { for_each_online_cpu(cpu) cleanup_workqueue_thread(wq, cpu); - spin_lock(&workqueue_lock); list_del(&wq->list); - spin_unlock(&workqueue_lock); } - unlock_cpu_hotplug(); + mutex_unlock(&workqueue_mutex); free_percpu(wq->cpu_wq); kfree(wq); } +EXPORT_SYMBOL_GPL(destroy_workqueue); static struct workqueue_struct *keventd_wq; +/** + * schedule_work - put work task in global workqueue + * @work: job to be done + * + * This puts a job in the kernel-global workqueue. + */ int fastcall schedule_work(struct work_struct *work) { return queue_work(keventd_wq, work); } +EXPORT_SYMBOL(schedule_work); -int fastcall schedule_delayed_work(struct work_struct *work, unsigned long delay) +/** + * schedule_delayed_work - put work task in global workqueue after delay + * @dwork: job to be done + * @delay: number of jiffies to wait or 0 for immediate execution + * + * After waiting for a given time this puts a job in the kernel-global + * workqueue. + */ +int fastcall schedule_delayed_work(struct delayed_work *dwork, unsigned long delay) { - return queue_delayed_work(keventd_wq, work, delay); + return queue_delayed_work(keventd_wq, dwork, delay); } +EXPORT_SYMBOL(schedule_delayed_work); +/** + * schedule_delayed_work_on - queue work in global workqueue on CPU after delay + * @cpu: cpu to use + * @dwork: job to be done + * @delay: number of jiffies to wait + * + * After waiting for a given time this puts a job in the kernel-global + * workqueue on the specified CPU. + */ int schedule_delayed_work_on(int cpu, - struct work_struct *work, unsigned long delay) + struct delayed_work *dwork, unsigned long delay) { - int ret = 0; - struct timer_list *timer = &work->timer; - - if (!test_and_set_bit(0, &work->pending)) { - BUG_ON(timer_pending(timer)); - BUG_ON(!list_empty(&work->entry)); - /* This stores keventd_wq for the moment, for the timer_fn */ - work->wq_data = keventd_wq; - timer->expires = jiffies + delay; - timer->data = (unsigned long)work; - timer->function = delayed_work_timer_fn; - add_timer_on(timer, cpu); - ret = 1; - } - return ret; + return queue_delayed_work_on(cpu, keventd_wq, dwork, delay); } +EXPORT_SYMBOL(schedule_delayed_work_on); -int schedule_on_each_cpu(void (*func) (void *info), void *info) +/** + * schedule_on_each_cpu - call a function on each online CPU from keventd + * @func: the function to call + * + * Returns zero on success. + * Returns -ve errno on failure. + * + * Appears to be racy against CPU hotplug. + * + * schedule_on_each_cpu() is very slow. + */ +int schedule_on_each_cpu(work_func_t func) { int cpu; - struct work_struct *work; + struct work_struct *works; - work = kmalloc(NR_CPUS * sizeof(struct work_struct), GFP_KERNEL); - - if (!work) + works = alloc_percpu(struct work_struct); + if (!works) return -ENOMEM; + + mutex_lock(&workqueue_mutex); for_each_online_cpu(cpu) { - INIT_WORK(work + cpu, func, info); - __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), - work + cpu); + struct work_struct *work = per_cpu_ptr(works, cpu); + + INIT_WORK(work, func); + set_bit(WORK_STRUCT_PENDING, work_data_bits(work)); + __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), work); } + mutex_unlock(&workqueue_mutex); flush_workqueue(keventd_wq); - kfree(work); + free_percpu(works); return 0; } @@ -450,17 +653,18 @@ void flush_scheduled_work(void) { flush_workqueue(keventd_wq); } +EXPORT_SYMBOL(flush_scheduled_work); /** * cancel_rearming_delayed_workqueue - reliably kill off a delayed * work whose handler rearms the delayed work. * @wq: the controlling workqueue structure - * @work: the delayed work struct + * @dwork: the delayed work struct */ void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq, - struct work_struct *work) + struct delayed_work *dwork) { - while (!cancel_delayed_work(work)) + while (!cancel_delayed_work(dwork)) flush_workqueue(wq); } EXPORT_SYMBOL(cancel_rearming_delayed_workqueue); @@ -468,14 +672,40 @@ EXPORT_SYMBOL(cancel_rearming_delayed_workqueue); /** * cancel_rearming_delayed_work - reliably kill off a delayed keventd * work whose handler rearms the delayed work. - * @work: the delayed work struct + * @dwork: the delayed work struct */ -void cancel_rearming_delayed_work(struct work_struct *work) +void cancel_rearming_delayed_work(struct delayed_work *dwork) { - cancel_rearming_delayed_workqueue(keventd_wq, work); + cancel_rearming_delayed_workqueue(keventd_wq, dwork); } EXPORT_SYMBOL(cancel_rearming_delayed_work); +/** + * execute_in_process_context - reliably execute the routine with user context + * @fn: the function to execute + * @ew: guaranteed storage for the execute work structure (must + * be available when the work executes) + * + * Executes the function immediately if process context is available, + * otherwise schedules the function for delayed execution. + * + * Returns: 0 - function was executed + * 1 - function was scheduled for execution + */ +int execute_in_process_context(work_func_t fn, struct execute_work *ew) +{ + if (!in_interrupt()) { + fn(&ew->work); + return 0; + } + + INIT_WORK(&ew->work, fn); + schedule_work(&ew->work); + + return 1; +} +EXPORT_SYMBOL_GPL(execute_in_process_context); + int keventd_up(void) { return keventd_wq != NULL; @@ -497,16 +727,15 @@ int current_is_keventd(void) } -#ifdef CONFIG_HOTPLUG_CPU /* Take the work from this (downed) CPU. */ static void take_over_work(struct workqueue_struct *wq, unsigned int cpu) { struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); - LIST_HEAD(list); + struct list_head list; struct work_struct *work; spin_lock_irq(&cwq->lock); - list_splice_init(&cwq->worklist, &list); + list_replace_init(&cwq->worklist, &list); while (!list_empty(&list)) { printk("Taking work for %s\n", wq->name); @@ -527,9 +756,10 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, switch (action) { case CPU_UP_PREPARE: + mutex_lock(&workqueue_mutex); /* Create a new workqueue thread for it. */ list_for_each_entry(wq, &workqueues, list) { - if (!create_workqueue_thread(wq, hotcpu)) { + if (!create_workqueue_thread(wq, hotcpu, 0)) { printk("workqueue for %i failed\n", hotcpu); return NOTIFY_BAD; } @@ -545,15 +775,27 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, kthread_bind(cwq->thread, hotcpu); wake_up_process(cwq->thread); } + mutex_unlock(&workqueue_mutex); break; case CPU_UP_CANCELED: list_for_each_entry(wq, &workqueues, list) { + if (!per_cpu_ptr(wq->cpu_wq, hotcpu)->thread) + continue; /* Unbind so it can run. */ kthread_bind(per_cpu_ptr(wq->cpu_wq, hotcpu)->thread, any_online_cpu(cpu_online_map)); cleanup_workqueue_thread(wq, hotcpu); } + mutex_unlock(&workqueue_mutex); + break; + + case CPU_DOWN_PREPARE: + mutex_lock(&workqueue_mutex); + break; + + case CPU_DOWN_FAILED: + mutex_unlock(&workqueue_mutex); break; case CPU_DEAD: @@ -561,12 +803,12 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb, cleanup_workqueue_thread(wq, hotcpu); list_for_each_entry(wq, &workqueues, list) take_over_work(wq, hotcpu); + mutex_unlock(&workqueue_mutex); break; } return NOTIFY_OK; } -#endif void init_workqueues(void) { @@ -576,13 +818,3 @@ void init_workqueues(void) BUG_ON(!keventd_wq); } -EXPORT_SYMBOL_GPL(__create_workqueue); -EXPORT_SYMBOL_GPL(queue_work); -EXPORT_SYMBOL_GPL(queue_delayed_work); -EXPORT_SYMBOL_GPL(flush_workqueue); -EXPORT_SYMBOL_GPL(destroy_workqueue); - -EXPORT_SYMBOL(schedule_work); -EXPORT_SYMBOL(schedule_delayed_work); -EXPORT_SYMBOL(schedule_delayed_work_on); -EXPORT_SYMBOL(flush_scheduled_work);