workqueue: introduce cpu_singlethread_map
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>
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index ce72d45..6308a4b 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -69,6 +69,7 @@
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 @@
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 @@
*/
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 @@
*/
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 @@
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 @@
*/
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 @@
{
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);