exile operation       = list_del_init(&worker->entry).
and destory operation -> list_del_init(&worker->entry).

so we can use list_empty(&worker->entry) to know: does the worker
has been exiled or killed.

WORKER_REBIND is not need any more, remove it to reduce the states
of workers.

Signed-off-by: Lai Jiangshan <la...@cn.fujitsu.com>
---
 kernel/workqueue.c |   21 ++++++++-------------
 1 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 4863162..aa46308 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -72,11 +72,10 @@ enum {
        WORKER_DIE              = 1 << 1,       /* die die die */
        WORKER_IDLE             = 1 << 2,       /* is idle */
        WORKER_PREP             = 1 << 3,       /* preparing to run works */
-       WORKER_REBIND           = 1 << 5,       /* mom is home, come back */
        WORKER_CPU_INTENSIVE    = 1 << 6,       /* cpu intensive */
        WORKER_UNBOUND          = 1 << 7,       /* worker is unbound */
 
-       WORKER_NOT_RUNNING      = WORKER_PREP | WORKER_REBIND | WORKER_UNBOUND |
+       WORKER_NOT_RUNNING      = WORKER_PREP | WORKER_UNBOUND |
                                  WORKER_CPU_INTENSIVE,
 
        NR_WORKER_POOLS         = 2,            /* # worker pools per gcwq */
@@ -1613,7 +1612,7 @@ __acquires(&gcwq->lock)
 
 /*
  * Rebind an idle @worker to its CPU. worker_thread() will test
- * %WORKER_REBIND before leaving idle and call this function.
+ * worker->entry before leaving idle and call this function.
  */
 static void idle_worker_rebind(struct worker *worker)
 {
@@ -1622,7 +1621,6 @@ static void idle_worker_rebind(struct worker *worker)
        if (worker_maybe_bind_and_lock(worker))
                worker_clr_flags(worker, WORKER_UNBOUND);
 
-       worker_clr_flags(worker, WORKER_REBIND);
        list_add(&worker->entry, &worker->pool->idle_list);
        spin_unlock_irq(&gcwq->lock);
 }
@@ -1675,11 +1673,9 @@ static void rebind_workers(struct global_cwq *gcwq)
        for_each_worker_pool(pool, gcwq)
                lockdep_assert_held(&pool->assoc_mutex);
 
-       /* set REBIND and kick idle ones */
+       /* exile and kick idle ones */
        for_each_worker_pool(pool, gcwq) {
                list_for_each_entry_safe(worker, n, &pool->idle_list, entry) {
-                       worker->flags |= WORKER_REBIND;
-
                        /* exile idle workers */
                        list_del_init(&worker->entry);
 
@@ -2145,7 +2141,7 @@ __acquires(&gcwq->lock)
         * necessary to avoid spurious warnings from rescuers servicing the
         * unbound or a disassociated gcwq.
         */
-       WARN_ON_ONCE(!(worker->flags & (WORKER_UNBOUND | WORKER_REBIND)) &&
+       WARN_ON_ONCE(!(worker->flags & WORKER_UNBOUND) &&
                     !(gcwq->flags & GCWQ_DISASSOCIATED) &&
                     raw_smp_processor_id() != gcwq->cpu);
 
@@ -2269,18 +2265,17 @@ static int worker_thread(void *__worker)
 woke_up:
        spin_lock_irq(&gcwq->lock);
 
-       /*
-        * DIE can be set only while idle and REBIND set while busy has
-        * @worker->rebind_work scheduled.  Checking here is enough.
-        */
-       if (unlikely(worker->flags & (WORKER_REBIND | WORKER_DIE))) {
+       /* Is it still home ? */
+       if (unlikely(list_empty(&worker->entry))) {
                spin_unlock_irq(&gcwq->lock);
 
+               /* reason: DIE */
                if (worker->flags & WORKER_DIE) {
                        worker->task->flags &= ~PF_WQ_WORKER;
                        return 0;
                }
 
+               /* reason: idle rebind */
                idle_worker_rebind(worker);
                goto woke_up;
        }
-- 
1.7.4.4

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