linux/kernel/workqueue.c

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/*
* linux/kernel/workqueue.c
*
* Generic mechanism for defining kernel helper threads for running
* arbitrary tasks in process context.
*
* Started by Ingo Molnar, Copyright (C) 2002
*
* Derived from the taskqueue/keventd code by:
*
* David Woodhouse <dwmw2@infradead.org>
* Andrew Morton <andrewm@uow.edu.au>
* Kai Petzke <wpp@marie.physik.tu-berlin.de>
* Theodore Ts'o <tytso@mit.edu>
*
* Made to use alloc_percpu by Christoph Lameter <clameter@sgi.com>.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/signal.h>
#include <linux/completion.h>
#include <linux/workqueue.h>
#include <linux/slab.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <linux/kthread.h>
#include <linux/hardirq.h>
#include <linux/mempolicy.h>
#include <linux/freezer.h>
#include <linux/kallsyms.h>
#include <linux/debug_locks.h>
/*
* 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 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.
*/
struct cpu_workqueue_struct {
spinlock_t lock;
long remove_sequence; /* Least-recently added (next to run) */
long insert_sequence; /* Next to add */
struct list_head worklist;
wait_queue_head_t more_work;
wait_queue_head_t work_done;
struct workqueue_struct *wq;
struct task_struct *thread;
int run_depth; /* Detect run_workqueue() recursion depth */
int freezeable; /* Freeze the thread during suspend */
} ____cacheline_aligned;
/*
* The externally visible workqueue abstraction is an array of
* per-CPU workqueues:
*/
struct workqueue_struct {
struct cpu_workqueue_struct *cpu_wq;
const char *name;
struct list_head list; /* Empty if single thread */
};
/* All the per-cpu workqueues on the system, for hotplug cpu to add/remove
threads to each one as cpus come/go. */
static DEFINE_MUTEX(workqueue_mutex);
static LIST_HEAD(workqueues);
static int singlethread_cpu;
/* If it's single threaded, it isn't in the list of workqueues. */
static inline int is_single_threaded(struct workqueue_struct *wq)
{
return list_empty(&wq->list);
}
[PATCH] WorkStruct: Use direct assignment rather than cmpxchg() Use direct assignment rather than cmpxchg() as the latter is unavailable and unimplementable on some platforms and is actually unnecessary. The use of cmpxchg() was to guard against two possibilities, neither of which can actually occur: (1) The pending flag may have been unset or may be cleared. However, given where it's called, the pending flag is _always_ set. I don't think it can be unset whilst we're in set_wq_data(). Once the work is enqueued to be actually run, the only way off the queue is for it to be actually run. If it's a delayed work item, then the bit can't be cleared by the timer because we haven't started the timer yet. Also, the pending bit can't be cleared by cancelling the delayed work _until_ the work item has had its timer started. (2) The workqueue pointer might change. This can only happen in two cases: (a) The work item has just been queued to actually run, and so we're protected by the appropriate workqueue spinlock. (b) A delayed work item is being queued, and so the timer hasn't been started yet, and so no one else knows about the work item or can access it (the pending bit protects us). Besides, set_wq_data() _sets_ the workqueue pointer unconditionally, so it can be assigned instead. So, replacing the set_wq_data() with a straight assignment would be okay in most cases. The problem is where we end up tangling with test_and_set_bit() emulated using spinlocks, and even then it's not a problem _provided_ test_and_set_bit() doesn't attempt to modify the word if the bit was set. If that's a problem, then a bitops-proofed assignment will be required - equivalent to atomic_set() vs other atomic_xxx() ops. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 12:33:26 +01:00
/*
* 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)
{
[PATCH] WorkStruct: Use direct assignment rather than cmpxchg() Use direct assignment rather than cmpxchg() as the latter is unavailable and unimplementable on some platforms and is actually unnecessary. The use of cmpxchg() was to guard against two possibilities, neither of which can actually occur: (1) The pending flag may have been unset or may be cleared. However, given where it's called, the pending flag is _always_ set. I don't think it can be unset whilst we're in set_wq_data(). Once the work is enqueued to be actually run, the only way off the queue is for it to be actually run. If it's a delayed work item, then the bit can't be cleared by the timer because we haven't started the timer yet. Also, the pending bit can't be cleared by cancelling the delayed work _until_ the work item has had its timer started. (2) The workqueue pointer might change. This can only happen in two cases: (a) The work item has just been queued to actually run, and so we're protected by the appropriate workqueue spinlock. (b) A delayed work item is being queued, and so the timer hasn't been started yet, and so no one else knows about the work item or can access it (the pending bit protects us). Besides, set_wq_data() _sets_ the workqueue pointer unconditionally, so it can be assigned instead. So, replacing the set_wq_data() with a straight assignment would be okay in most cases. The problem is where we end up tangling with test_and_set_bit() emulated using spinlocks, and even then it's not a problem _provided_ test_and_set_bit() doesn't attempt to modify the word if the bit was set. If that's a problem, then a bitops-proofed assignment will be required - equivalent to atomic_set() vs other atomic_xxx() ops. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 12:33:26 +01:00
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)
{
unsigned long flags;
spin_lock_irqsave(&cwq->lock, flags);
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 - 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.
*/
int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work)
{
int ret = 0, cpu = get_cpu();
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));
__queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
ret = 1;
}
put_cpu();
return ret;
}
EXPORT_SYMBOL_GPL(queue_work);
[PATCH] Add debugging feature /proc/timer_stat Add /proc/timer_stats support: debugging feature to profile timer expiration. Both the starting site, process/PID and the expiration function is captured. This allows the quick identification of timer event sources in a system. Sample output: # echo 1 > /proc/timer_stats # cat /proc/timer_stats Timer Stats Version: v0.1 Sample period: 4.010 s 24, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 11, 0 swapper sk_reset_timer (tcp_delack_timer) 6, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 17, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 4, 2050 pcscd do_nanosleep (hrtimer_wakeup) 5, 4179 sshd sk_reset_timer (tcp_write_timer) 4, 2248 yum-updatesd schedule_timeout (process_timeout) 18, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 3, 0 swapper sk_reset_timer (tcp_delack_timer) 1, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer) 2, 1 swapper e1000_up (e1000_watchdog) 1, 1 init schedule_timeout (process_timeout) 100 total events, 25.24 events/sec [ cleanups and hrtimers support from Thomas Gleixner <tglx@linutronix.de> ] [bunk@stusta.de: nr_entries can become static] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16 10:28:13 +01:00
void delayed_work_timer_fn(unsigned long __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), &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 delayed_work *dwork, unsigned long delay)
{
int ret = 0;
struct timer_list *timer = &dwork->timer;
struct work_struct *work = &dwork->work;
[PATCH] Add debugging feature /proc/timer_stat Add /proc/timer_stats support: debugging feature to profile timer expiration. Both the starting site, process/PID and the expiration function is captured. This allows the quick identification of timer event sources in a system. Sample output: # echo 1 > /proc/timer_stats # cat /proc/timer_stats Timer Stats Version: v0.1 Sample period: 4.010 s 24, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 11, 0 swapper sk_reset_timer (tcp_delack_timer) 6, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 17, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 4, 2050 pcscd do_nanosleep (hrtimer_wakeup) 5, 4179 sshd sk_reset_timer (tcp_write_timer) 4, 2248 yum-updatesd schedule_timeout (process_timeout) 18, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 3, 0 swapper sk_reset_timer (tcp_delack_timer) 1, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer) 2, 1 swapper e1000_up (e1000_watchdog) 1, 1 init schedule_timeout (process_timeout) 100 total events, 25.24 events/sec [ cleanups and hrtimers support from Thomas Gleixner <tglx@linutronix.de> ] [bunk@stusta.de: nr_entries can become static] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16 10:28:13 +01:00
timer_stats_timer_set_start_info(timer);
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 */
set_wq_data(work, wq);
timer->expires = jiffies + delay;
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)
{
unsigned long flags;
/*
* Keep taking off work from the queue until
* done.
*/
spin_lock_irqsave(&cwq->lock, flags);
cwq->run_depth++;
if (cwq->run_depth > 3) {
/* morton gets to eat his hat */
printk("%s: recursion depth exceeded: %d\n",
__FUNCTION__, cwq->run_depth);
dump_stack();
}
while (!list_empty(&cwq->worklist)) {
struct work_struct *work = list_entry(cwq->worklist.next,
struct work_struct, entry);
work_func_t f = work->func;
list_del_init(cwq->worklist.next);
spin_unlock_irqrestore(&cwq->lock, flags);
BUG_ON(get_wq_data(work) != cwq);
if (!test_bit(WORK_STRUCT_NOAUTOREL, work_data_bits(work)))
2006-11-22 15:55:48 +01:00
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++;
wake_up(&cwq->work_done);
}
cwq->run_depth--;
spin_unlock_irqrestore(&cwq->lock, flags);
}
static int worker_thread(void *__cwq)
{
struct cpu_workqueue_struct *cwq = __cwq;
DECLARE_WAITQUEUE(wait, current);
struct k_sigaction sa;
sigset_t blocked;
if (!cwq->freezeable)
current->flags |= PF_NOFREEZE;
set_user_nice(current, -5);
/* Block and flush all signals */
sigfillset(&blocked);
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;
siginitset(&sa.sa.sa_mask, sigmask(SIGCHLD));
do_sigaction(SIGCHLD, &sa, (struct k_sigaction *)0);
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();
else
__set_current_state(TASK_RUNNING);
remove_wait_queue(&cwq->more_work, &wait);
if (!list_empty(&cwq->worklist))
run_workqueue(cwq);
set_current_state(TASK_INTERRUPTIBLE);
}
__set_current_state(TASK_RUNNING);
return 0;
}
static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq)
{
if (cwq->thread == current) {
/*
* Probably keventd trying to flush its own queue. So simply run
* it by hand rather than deadlocking.
*/
run_workqueue(cwq);
} else {
DEFINE_WAIT(wait);
long sequence_needed;
spin_lock_irq(&cwq->lock);
sequence_needed = cwq->insert_sequence;
while (sequence_needed - cwq->remove_sequence > 0) {
prepare_to_wait(&cwq->work_done, &wait,
TASK_UNINTERRUPTIBLE);
spin_unlock_irq(&cwq->lock);
schedule();
spin_lock_irq(&cwq->lock);
}
finish_wait(&cwq->work_done, &wait);
spin_unlock_irq(&cwq->lock);
}
}
/**
* 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.
*
* This function will sample each workqueue's current insert_sequence number and
* will sleep until the head sequence is greater than or equal to that. This
* means that we sleep until all works which were queued on entry have been
* handled, but we are not livelocked by new incoming ones.
*
* This function used to run the workqueues itself. Now we just wait for the
* helper threads to do it.
*/
void fastcall flush_workqueue(struct workqueue_struct *wq)
{
might_sleep();
if (is_single_threaded(wq)) {
/* Always use first cpu's area. */
flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, singlethread_cpu));
} else {
int cpu;
mutex_lock(&workqueue_mutex);
for_each_online_cpu(cpu)
flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu));
mutex_unlock(&workqueue_mutex);
}
}
EXPORT_SYMBOL_GPL(flush_workqueue);
static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq,
int cpu, int freezeable)
{
struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu);
struct task_struct *p;
spin_lock_init(&cwq->lock);
cwq->wq = 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);
if (is_single_threaded(wq))
p = kthread_create(worker_thread, cwq, "%s", wq->name);
else
p = kthread_create(worker_thread, cwq, "%s/%d", wq->name, cpu);
if (IS_ERR(p))
return NULL;
cwq->thread = p;
return p;
}
struct workqueue_struct *__create_workqueue(const char *name,
int singlethread, int freezeable)
{
int cpu, destroy = 0;
struct workqueue_struct *wq;
struct task_struct *p;
wq = kzalloc(sizeof(*wq), GFP_KERNEL);
if (!wq)
return NULL;
wq->cpu_wq = alloc_percpu(struct cpu_workqueue_struct);
if (!wq->cpu_wq) {
kfree(wq);
return NULL;
}
wq->name = name;
mutex_lock(&workqueue_mutex);
if (singlethread) {
INIT_LIST_HEAD(&wq->list);
p = create_workqueue_thread(wq, singlethread_cpu, freezeable);
if (!p)
destroy = 1;
else
wake_up_process(p);
} else {
list_add(&wq->list, &workqueues);
for_each_online_cpu(cpu) {
p = create_workqueue_thread(wq, cpu, freezeable);
if (p) {
kthread_bind(p, cpu);
wake_up_process(p);
} else
destroy = 1;
}
}
mutex_unlock(&workqueue_mutex);
/*
* Was there any error during startup? If yes then clean up:
*/
if (destroy) {
destroy_workqueue(wq);
wq = NULL;
}
return wq;
}
EXPORT_SYMBOL_GPL(__create_workqueue);
static void cleanup_workqueue_thread(struct workqueue_struct *wq, int cpu)
{
struct cpu_workqueue_struct *cwq;
unsigned long flags;
struct task_struct *p;
cwq = per_cpu_ptr(wq->cpu_wq, cpu);
spin_lock_irqsave(&cwq->lock, flags);
p = cwq->thread;
cwq->thread = NULL;
spin_unlock_irqrestore(&cwq->lock, flags);
if (p)
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;
flush_workqueue(wq);
/* We don't need the distraction of CPUs appearing and vanishing. */
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);
list_del(&wq->list);
}
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);
/**
* 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.
*/
[PATCH] Add debugging feature /proc/timer_stat Add /proc/timer_stats support: debugging feature to profile timer expiration. Both the starting site, process/PID and the expiration function is captured. This allows the quick identification of timer event sources in a system. Sample output: # echo 1 > /proc/timer_stats # cat /proc/timer_stats Timer Stats Version: v0.1 Sample period: 4.010 s 24, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 11, 0 swapper sk_reset_timer (tcp_delack_timer) 6, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 17, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 4, 2050 pcscd do_nanosleep (hrtimer_wakeup) 5, 4179 sshd sk_reset_timer (tcp_write_timer) 4, 2248 yum-updatesd schedule_timeout (process_timeout) 18, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 3, 0 swapper sk_reset_timer (tcp_delack_timer) 1, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer) 2, 1 swapper e1000_up (e1000_watchdog) 1, 1 init schedule_timeout (process_timeout) 100 total events, 25.24 events/sec [ cleanups and hrtimers support from Thomas Gleixner <tglx@linutronix.de> ] [bunk@stusta.de: nr_entries can become static] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16 10:28:13 +01:00
int fastcall schedule_delayed_work(struct delayed_work *dwork,
unsigned long delay)
{
[PATCH] Add debugging feature /proc/timer_stat Add /proc/timer_stats support: debugging feature to profile timer expiration. Both the starting site, process/PID and the expiration function is captured. This allows the quick identification of timer event sources in a system. Sample output: # echo 1 > /proc/timer_stats # cat /proc/timer_stats Timer Stats Version: v0.1 Sample period: 4.010 s 24, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 11, 0 swapper sk_reset_timer (tcp_delack_timer) 6, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 17, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 2, 1 swapper queue_delayed_work_on (delayed_work_timer_fn) 4, 2050 pcscd do_nanosleep (hrtimer_wakeup) 5, 4179 sshd sk_reset_timer (tcp_write_timer) 4, 2248 yum-updatesd schedule_timeout (process_timeout) 18, 0 swapper hrtimer_restart_sched_tick (hrtimer_sched_tick) 3, 0 swapper sk_reset_timer (tcp_delack_timer) 1, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer) 2, 1 swapper e1000_up (e1000_watchdog) 1, 1 init schedule_timeout (process_timeout) 100 total events, 25.24 events/sec [ cleanups and hrtimers support from Thomas Gleixner <tglx@linutronix.de> ] [bunk@stusta.de: nr_entries can become static] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16 10:28:13 +01:00
timer_stats_timer_set_start_info(&dwork->timer);
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 delayed_work *dwork, unsigned long delay)
{
return queue_delayed_work_on(cpu, keventd_wq, dwork, delay);
}
EXPORT_SYMBOL(schedule_delayed_work_on);
/**
* 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.
*/
2006-11-22 15:55:48 +01:00
int schedule_on_each_cpu(work_func_t func)
{
int cpu;
struct work_struct *works;
works = alloc_percpu(struct work_struct);
if (!works)
return -ENOMEM;
mutex_lock(&workqueue_mutex);
for_each_online_cpu(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);
free_percpu(works);
return 0;
}
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
* @dwork: the delayed work struct
*/
void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq,
struct delayed_work *dwork)
{
while (!cancel_delayed_work(dwork))
flush_workqueue(wq);
}
EXPORT_SYMBOL(cancel_rearming_delayed_workqueue);
/**
* cancel_rearming_delayed_work - reliably kill off a delayed keventd work whose handler rearms the delayed work.
* @dwork: the delayed work struct
*/
void cancel_rearming_delayed_work(struct delayed_work *dwork)
{
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
*/
2006-11-22 15:55:48 +01:00
int execute_in_process_context(work_func_t fn, struct execute_work *ew)
{
if (!in_interrupt()) {
2006-11-22 15:55:48 +01:00
fn(&ew->work);
return 0;
}
2006-11-22 15:55:48 +01:00
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;
}
int current_is_keventd(void)
{
struct cpu_workqueue_struct *cwq;
int cpu = smp_processor_id(); /* preempt-safe: keventd is per-cpu */
int ret = 0;
BUG_ON(!keventd_wq);
cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu);
if (current == cwq->thread)
ret = 1;
return ret;
}
/* 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);
struct list_head list;
struct work_struct *work;
spin_lock_irq(&cwq->lock);
list_replace_init(&cwq->worklist, &list);
while (!list_empty(&list)) {
printk("Taking work for %s\n", wq->name);
work = list_entry(list.next,struct work_struct,entry);
list_del(&work->entry);
__queue_work(per_cpu_ptr(wq->cpu_wq, smp_processor_id()), work);
}
spin_unlock_irq(&cwq->lock);
}
/* We're holding the cpucontrol mutex here */
static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
unsigned long action,
void *hcpu)
{
unsigned int hotcpu = (unsigned long)hcpu;
struct workqueue_struct *wq;
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, 0)) {
printk("workqueue for %i failed\n", hotcpu);
return NOTIFY_BAD;
}
}
break;
case CPU_ONLINE:
/* Kick off worker threads. */
list_for_each_entry(wq, &workqueues, list) {
struct cpu_workqueue_struct *cwq;
cwq = per_cpu_ptr(wq->cpu_wq, hotcpu);
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:
list_for_each_entry(wq, &workqueues, list)
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;
}
void init_workqueues(void)
{
singlethread_cpu = first_cpu(cpu_possible_map);
hotcpu_notifier(workqueue_cpu_callback, 0);
keventd_wq = create_workqueue("events");
BUG_ON(!keventd_wq);
}