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workqueue: introduce cpu_singlethread_map

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The code like

	if (is_single_threaded(wq))
		do_something(singlethread_cpu);
	else {
		for_each_cpu_mask(cpu, cpu_populated_map)
			do_something(cpu);
	}

looks very annoying. We can add "static cpumask_t cpu_singlethread_map" and
simplify the code. Lessens .text a bit, and imho makes the code more readable.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2007-05-09 02:34:12 -07:00 committed by Linus Torvalds
parent dfb4b82e1c
commit b1f4ec172f
1 changed files with 25 additions and 30 deletions
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55
kernel/workqueue.c
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@ -69,6 +69,7 @@ static DEFINE_MUTEX(workqueue_mutex);
static LIST_HEAD(workqueues);
static int singlethread_cpu __read_mostly;
static cpumask_t cpu_singlethread_map __read_mostly;
/* optimization, we could use cpu_possible_map */
static cpumask_t cpu_populated_map __read_mostly;
@ -78,6 +79,12 @@ static inline int is_single_threaded(struct workqueue_struct *wq)
return list_empty(&wq->list);
}
static const cpumask_t *wq_cpu_map(struct workqueue_struct *wq)
{
return is_single_threaded(wq)
? &cpu_singlethread_map : &cpu_populated_map;
}
/*
* Set the workqueue on which a work item is to be run
* - Must *only* be called if the pending flag is set
@ -393,16 +400,12 @@ static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq)
*/
void fastcall flush_workqueue(struct workqueue_struct *wq)
{
const cpumask_t *cpu_map = wq_cpu_map(wq);
int cpu
might_sleep();
if (is_single_threaded(wq))
flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, singlethread_cpu));
else {
int cpu;
for_each_cpu_mask(cpu, cpu_populated_map)
flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu));
}
for_each_cpu_mask(cpu, *cpu_map)
flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu));
}
EXPORT_SYMBOL_GPL(flush_workqueue);
@ -439,7 +442,9 @@ static void wait_on_work(struct cpu_workqueue_struct *cwq,
*/
void flush_work(struct workqueue_struct *wq, struct work_struct *work)
{
const cpumask_t *cpu_map = wq_cpu_map(wq);
struct cpu_workqueue_struct *cwq;
int cpu;
might_sleep();
@ -457,14 +462,8 @@ void flush_work(struct workqueue_struct *wq, struct work_struct *work)
work_release(work);
spin_unlock_irq(&cwq->lock);
if (is_single_threaded(wq))
wait_on_work(per_cpu_ptr(wq->cpu_wq, singlethread_cpu), work);
else {
int cpu;
for_each_cpu_mask(cpu, cpu_populated_map)
wait_on_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
}
for_each_cpu_mask(cpu, *cpu_map)
wait_on_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
}
EXPORT_SYMBOL_GPL(flush_work);
@ -757,22 +756,17 @@ static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
*/
void destroy_workqueue(struct workqueue_struct *wq)
{
const cpumask_t *cpu_map = wq_cpu_map(wq);
struct cpu_workqueue_struct *cwq;
int cpu;
if (is_single_threaded(wq)) {
cwq = per_cpu_ptr(wq->cpu_wq, singlethread_cpu);
cleanup_workqueue_thread(cwq, singlethread_cpu);
} else {
int cpu;
mutex_lock(&workqueue_mutex);
list_del(&wq->list);
mutex_unlock(&workqueue_mutex);
mutex_lock(&workqueue_mutex);
list_del(&wq->list);
mutex_unlock(&workqueue_mutex);
for_each_cpu_mask(cpu, cpu_populated_map) {
cwq = per_cpu_ptr(wq->cpu_wq, cpu);
cleanup_workqueue_thread(cwq, cpu);
}
for_each_cpu_mask(cpu, *cpu_map) {
cwq = per_cpu_ptr(wq->cpu_wq, cpu);
cleanup_workqueue_thread(cwq, cpu);
}
free_percpu(wq->cpu_wq);
@ -831,6 +825,7 @@ void init_workqueues(void)
{
cpu_populated_map = cpu_online_map;
singlethread_cpu = first_cpu(cpu_possible_map);
cpu_singlethread_map = cpumask_of_cpu(singlethread_cpu);
hotcpu_notifier(workqueue_cpu_callback, 0);
keventd_wq = create_workqueue("events");
BUG_ON(!keventd_wq);