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-rw-r--r--kernel/workqueue.c173
1 files changed, 59 insertions, 114 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index f7ab703285a6..dc78956ccf03 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -55,6 +55,7 @@ struct cpu_workqueue_struct {
struct list_head worklist;
wait_queue_head_t more_work;
struct work_struct *current_work;
+ unsigned int cpu;
struct workqueue_struct *wq; /* I: the owning workqueue */
struct task_struct *thread;
@@ -189,34 +190,19 @@ static DEFINE_SPINLOCK(workqueue_lock);
static LIST_HEAD(workqueues);
static int singlethread_cpu __read_mostly;
-static const struct cpumask *cpu_singlethread_map __read_mostly;
-/*
- * _cpu_down() first removes CPU from cpu_online_map, then CPU_DEAD
- * flushes cwq->worklist. This means that flush_workqueue/wait_on_work
- * which comes in between can't use for_each_online_cpu(). We could
- * use cpu_possible_map, the cpumask below is more a documentation
- * than optimization.
- */
-static cpumask_var_t cpu_populated_map __read_mostly;
-
-/* If it's single threaded, it isn't in the list of workqueues. */
-static inline bool is_wq_single_threaded(struct workqueue_struct *wq)
-{
- return wq->flags & WQ_SINGLE_THREAD;
-}
-static const struct cpumask *wq_cpu_map(struct workqueue_struct *wq)
+static struct cpu_workqueue_struct *get_cwq(unsigned int cpu,
+ struct workqueue_struct *wq)
{
- return is_wq_single_threaded(wq)
- ? cpu_singlethread_map : cpu_populated_map;
+ return per_cpu_ptr(wq->cpu_wq, cpu);
}
-static struct cpu_workqueue_struct *get_cwq(unsigned int cpu,
- struct workqueue_struct *wq)
+static struct cpu_workqueue_struct *target_cwq(unsigned int cpu,
+ struct workqueue_struct *wq)
{
- if (unlikely(is_wq_single_threaded(wq)))
+ if (unlikely(wq->flags & WQ_SINGLE_THREAD))
cpu = singlethread_cpu;
- return per_cpu_ptr(wq->cpu_wq, cpu);
+ return get_cwq(cpu, wq);
}
/*
@@ -279,7 +265,7 @@ static void insert_work(struct cpu_workqueue_struct *cwq,
static void __queue_work(unsigned int cpu, struct workqueue_struct *wq,
struct work_struct *work)
{
- struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+ struct cpu_workqueue_struct *cwq = target_cwq(cpu, wq);
unsigned long flags;
debug_work_activate(work);
@@ -383,7 +369,7 @@ int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
timer_stats_timer_set_start_info(&dwork->timer);
/* This stores cwq for the moment, for the timer_fn */
- set_wq_data(work, get_cwq(raw_smp_processor_id(), wq), 0);
+ set_wq_data(work, target_cwq(raw_smp_processor_id(), wq), 0);
timer->expires = jiffies + delay;
timer->data = (unsigned long)dwork;
timer->function = delayed_work_timer_fn;
@@ -495,6 +481,10 @@ static int worker_thread(void *__cwq)
if (kthread_should_stop())
break;
+ if (unlikely(!cpumask_equal(&cwq->thread->cpus_allowed,
+ get_cpu_mask(cwq->cpu))))
+ set_cpus_allowed_ptr(cwq->thread,
+ get_cpu_mask(cwq->cpu));
run_workqueue(cwq);
}
@@ -574,14 +564,13 @@ static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq)
*/
void flush_workqueue(struct workqueue_struct *wq)
{
- const struct cpumask *cpu_map = wq_cpu_map(wq);
int cpu;
might_sleep();
lock_map_acquire(&wq->lockdep_map);
lock_map_release(&wq->lockdep_map);
- for_each_cpu(cpu, cpu_map)
- flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu));
+ for_each_possible_cpu(cpu)
+ flush_cpu_workqueue(get_cwq(cpu, wq));
}
EXPORT_SYMBOL_GPL(flush_workqueue);
@@ -699,7 +688,6 @@ static void wait_on_work(struct work_struct *work)
{
struct cpu_workqueue_struct *cwq;
struct workqueue_struct *wq;
- const struct cpumask *cpu_map;
int cpu;
might_sleep();
@@ -712,9 +700,8 @@ static void wait_on_work(struct work_struct *work)
return;
wq = cwq->wq;
- cpu_map = wq_cpu_map(wq);
- for_each_cpu(cpu, cpu_map)
+ for_each_possible_cpu(cpu)
wait_on_cpu_work(get_cwq(cpu, wq), work);
}
@@ -972,7 +959,7 @@ int current_is_keventd(void)
BUG_ON(!keventd_wq);
- cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu);
+ cwq = get_cwq(cpu, keventd_wq);
if (current == cwq->thread)
ret = 1;
@@ -980,26 +967,12 @@ int current_is_keventd(void)
}
-static struct cpu_workqueue_struct *
-init_cpu_workqueue(struct workqueue_struct *wq, int cpu)
-{
- struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu);
-
- cwq->wq = wq;
- spin_lock_init(&cwq->lock);
- INIT_LIST_HEAD(&cwq->worklist);
- init_waitqueue_head(&cwq->more_work);
-
- return cwq;
-}
-
static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
{
struct workqueue_struct *wq = cwq->wq;
- const char *fmt = is_wq_single_threaded(wq) ? "%s" : "%s/%d";
struct task_struct *p;
- p = kthread_create(worker_thread, cwq, fmt, wq->name, cpu);
+ p = kthread_create(worker_thread, cwq, "%s/%d", wq->name, cpu);
/*
* Nobody can add the work_struct to this cwq,
* if (caller is __create_workqueue)
@@ -1031,8 +1004,8 @@ struct workqueue_struct *__create_workqueue_key(const char *name,
struct lock_class_key *key,
const char *lock_name)
{
+ bool singlethread = flags & WQ_SINGLE_THREAD;
struct workqueue_struct *wq;
- struct cpu_workqueue_struct *cwq;
int err = 0, cpu;
wq = kzalloc(sizeof(*wq), GFP_KERNEL);
@@ -1048,37 +1021,37 @@ struct workqueue_struct *__create_workqueue_key(const char *name,
lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
INIT_LIST_HEAD(&wq->list);
- if (flags & WQ_SINGLE_THREAD) {
- cwq = init_cpu_workqueue(wq, singlethread_cpu);
- err = create_workqueue_thread(cwq, singlethread_cpu);
- start_workqueue_thread(cwq, -1);
- } else {
- cpu_maps_update_begin();
- /*
- * We must place this wq on list even if the code below fails.
- * cpu_down(cpu) can remove cpu from cpu_populated_map before
- * destroy_workqueue() takes the lock, in that case we leak
- * cwq[cpu]->thread.
- */
- spin_lock(&workqueue_lock);
- list_add(&wq->list, &workqueues);
- spin_unlock(&workqueue_lock);
- /*
- * We must initialize cwqs for each possible cpu even if we
- * are going to call destroy_workqueue() finally. Otherwise
- * cpu_up() can hit the uninitialized cwq once we drop the
- * lock.
- */
- for_each_possible_cpu(cpu) {
- cwq = init_cpu_workqueue(wq, cpu);
- if (err || !cpu_online(cpu))
- continue;
- err = create_workqueue_thread(cwq, cpu);
+ cpu_maps_update_begin();
+ /*
+ * We must initialize cwqs for each possible cpu even if we
+ * are going to call destroy_workqueue() finally. Otherwise
+ * cpu_up() can hit the uninitialized cwq once we drop the
+ * lock.
+ */
+ for_each_possible_cpu(cpu) {
+ struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+
+ cwq->wq = wq;
+ cwq->cpu = cpu;
+ spin_lock_init(&cwq->lock);
+ INIT_LIST_HEAD(&cwq->worklist);
+ init_waitqueue_head(&cwq->more_work);
+
+ if (err)
+ continue;
+ err = create_workqueue_thread(cwq, cpu);
+ if (cpu_online(cpu) && !singlethread)
start_workqueue_thread(cwq, cpu);
- }
- cpu_maps_update_done();
+ else
+ start_workqueue_thread(cwq, -1);
}
+ spin_lock(&workqueue_lock);
+ list_add(&wq->list, &workqueues);
+ spin_unlock(&workqueue_lock);
+
+ cpu_maps_update_done();
+
if (err) {
destroy_workqueue(wq);
wq = NULL;
@@ -1128,17 +1101,16 @@ static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq)
*/
void destroy_workqueue(struct workqueue_struct *wq)
{
- const struct cpumask *cpu_map = wq_cpu_map(wq);
int cpu;
cpu_maps_update_begin();
spin_lock(&workqueue_lock);
list_del(&wq->list);
spin_unlock(&workqueue_lock);
+ cpu_maps_update_done();
- for_each_cpu(cpu, cpu_map)
- cleanup_workqueue_thread(per_cpu_ptr(wq->cpu_wq, cpu));
- cpu_maps_update_done();
+ for_each_possible_cpu(cpu)
+ cleanup_workqueue_thread(get_cwq(cpu, wq));
free_percpu(wq->cpu_wq);
kfree(wq);
@@ -1152,48 +1124,25 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
unsigned int cpu = (unsigned long)hcpu;
struct cpu_workqueue_struct *cwq;
struct workqueue_struct *wq;
- int err = 0;
action &= ~CPU_TASKS_FROZEN;
- switch (action) {
- case CPU_UP_PREPARE:
- cpumask_set_cpu(cpu, cpu_populated_map);
- }
-undo:
list_for_each_entry(wq, &workqueues, list) {
- cwq = per_cpu_ptr(wq->cpu_wq, cpu);
+ if (wq->flags & WQ_SINGLE_THREAD)
+ continue;
- switch (action) {
- case CPU_UP_PREPARE:
- err = create_workqueue_thread(cwq, cpu);
- if (!err)
- break;
- printk(KERN_ERR "workqueue [%s] for %i failed\n",
- wq->name, cpu);
- action = CPU_UP_CANCELED;
- err = -ENOMEM;
- goto undo;
-
- case CPU_ONLINE:
- start_workqueue_thread(cwq, cpu);
- break;
+ cwq = get_cwq(cpu, wq);
- case CPU_UP_CANCELED:
- start_workqueue_thread(cwq, -1);
+ switch (action) {
case CPU_POST_DEAD:
- cleanup_workqueue_thread(cwq);
+ lock_map_acquire(&cwq->wq->lockdep_map);
+ lock_map_release(&cwq->wq->lockdep_map);
+ flush_cpu_workqueue(cwq);
break;
}
}
- switch (action) {
- case CPU_UP_CANCELED:
- case CPU_POST_DEAD:
- cpumask_clear_cpu(cpu, cpu_populated_map);
- }
-
- return notifier_from_errno(err);
+ return notifier_from_errno(0);
}
#ifdef CONFIG_SMP
@@ -1245,11 +1194,7 @@ EXPORT_SYMBOL_GPL(work_on_cpu);
void __init init_workqueues(void)
{
- alloc_cpumask_var(&cpu_populated_map, GFP_KERNEL);
-
- cpumask_copy(cpu_populated_map, cpu_online_mask);
singlethread_cpu = cpumask_first(cpu_possible_mask);
- cpu_singlethread_map = cpumask_of(singlethread_cpu);
hotcpu_notifier(workqueue_cpu_callback, 0);
keventd_wq = create_workqueue("events");
BUG_ON(!keventd_wq);