workqueue: introduce workqueue_struct->singlethread

Add explicit workqueue_struct->singlethread flag.  This lessens .text a
little, but most importantly this allows us to manipulate wq->list without
changine the meaning of is_single_threaded().

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 6308a4bc6a821f654bedbab4fefb1999d67cfa5e..32b1091f21efb0b10760d86c1108ea15ba634627 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -58,8 +58,9 @@ struct cpu_workqueue_struct {
  */
 struct workqueue_struct {
        struct cpu_workqueue_struct *cpu_wq;
+       struct list_head list;
        const char *name;
-       struct list_head list;  /* Empty if single thread */
+       int singlethread;
        int freezeable;         /* Freeze threads during suspend */
 };
 
@@ -76,7 +77,7 @@ static cpumask_t cpu_populated_map __read_mostly;
 /* 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);
+       return wq->singlethread;
 }
 
 static const cpumask_t *wq_cpu_map(struct workqueue_struct *wq)
@@ -401,7 +402,7 @@ 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
+       int cpu;
 
        might_sleep();
        for_each_cpu_mask(cpu, *cpu_map)
@@ -694,10 +695,11 @@ struct workqueue_struct *__create_workqueue(const char *name,
        }
 
        wq->name = name;
+       wq->singlethread = singlethread;
        wq->freezeable = freezeable;
+       INIT_LIST_HEAD(&wq->list);
 
        if (singlethread) {
-               INIT_LIST_HEAD(&wq->list);
                cwq = init_cpu_workqueue(wq, singlethread_cpu);
                err = create_workqueue_thread(cwq, singlethread_cpu);
        } else {