From: Oleg Nesterov 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 Cc: Ingo Molnar Signed-off-by: Andrew Morton --- kernel/workqueue.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff -puN kernel/workqueue.c~workqueue-introduce-workqueue_struct-singlethread kernel/workqueue.c --- a/kernel/workqueue.c~workqueue-introduce-workqueue_struct-singlethread +++ a/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 __rea /* 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 c 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_workqu } 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 { _