gcwq_unbind_fn() unbind manager by ->manager pointer. rebinding-manger, unbinding/rebinding newly created worker are done by other place. so we don't need manager_mutex any more.
Also change the comment of @bind accordingly. Signed-off-by: Lai Jiangshan <[email protected]> --- kernel/workqueue.c | 52 ++++++++++++++++------------------------------------ 1 files changed, 16 insertions(+), 36 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 819c84e..5fb712a 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1667,17 +1667,15 @@ static void busy_worker_rebind_fn(struct work_struct *work) * add themselves back to idle_list if the gcwq is still associated. */ static void rebind_workers(struct global_cwq *gcwq) - __releases(&gcwq->lock) __acquires(&gcwq->lock) { struct worker_pool *pool; struct worker *worker, *n; struct hlist_node *pos; int i; - lockdep_assert_held(&gcwq->lock); + spin_lock_irq(&gcwq->lock); - for_each_worker_pool(pool, gcwq) - lockdep_assert_held(&pool->manager_mutex); + gcwq->flags &= ~GCWQ_DISASSOCIATED; /* exile and kick idle ones */ for_each_worker_pool(pool, gcwq) { @@ -1714,6 +1712,8 @@ static void rebind_workers(struct global_cwq *gcwq) worker->scheduled.next, work_color_to_flags(WORK_NO_COLOR)); } + + spin_unlock_irq(&gcwq->lock); } static struct worker *alloc_worker(void) @@ -1981,11 +1981,14 @@ __acquires(&gcwq->lock) bool bind; /* - * Note we have held the manage_mutex, so DISASSOCIATED can't be - * flipped and it is correct that we calculate @bind only once - * and then release the gcwq->lock. + * Snapshot the value of @bind. + * Because the %UNBOUND bit of manager can't be cleared while it + * is creating worker. So we can detect whether the real @bind + * is/was changed and fix the newly created worker's binding in + * manager_start_worker(). */ bind = !(gcwq->flags & GCWQ_DISASSOCIATED); + BUG_ON(!bind && !(pool->manager->flags & WORKER_UNBOUND)); if (!need_to_create_worker(pool)) return false; @@ -3441,26 +3444,6 @@ EXPORT_SYMBOL_GPL(work_busy); * cpu comes back online. */ -/* claim manager positions of all pools */ -static void gcwq_claim_management_and_lock(struct global_cwq *gcwq) -{ - struct worker_pool *pool; - - for_each_worker_pool(pool, gcwq) - mutex_lock_nested(&pool->manager_mutex, pool - gcwq->pools); - spin_lock_irq(&gcwq->lock); -} - -/* release manager positions */ -static void gcwq_release_management_and_unlock(struct global_cwq *gcwq) -{ - struct worker_pool *pool; - - spin_unlock_irq(&gcwq->lock); - for_each_worker_pool(pool, gcwq) - mutex_unlock(&pool->manager_mutex); -} - static void gcwq_unbind_fn(struct work_struct *work) { struct global_cwq *gcwq = get_gcwq(smp_processor_id()); @@ -3471,13 +3454,13 @@ static void gcwq_unbind_fn(struct work_struct *work) BUG_ON(gcwq->cpu != smp_processor_id()); - gcwq_claim_management_and_lock(gcwq); + spin_lock_irq(&gcwq->lock); /* - * We've claimed all manager positions. Make all workers unbound - * and set DISASSOCIATED. Before this, all workers except for the - * ones which are still executing works from before the last CPU - * down must be on the cpu. After this, they may become diasporas. + * Make all workers unbound and set DISASSOCIATED. + * Before this, all workers except for the ones which are still + * executing works from before the last CPU down must be on the cpu. + * After this, they may become diasporas. */ for_each_worker_pool(pool, gcwq) { list_for_each_entry(worker, &pool->idle_list, entry) @@ -3491,7 +3474,7 @@ static void gcwq_unbind_fn(struct work_struct *work) gcwq->flags |= GCWQ_DISASSOCIATED; - gcwq_release_management_and_unlock(gcwq); + spin_unlock_irq(&gcwq->lock); /* * Call schedule() so that we cross rq->lock and thus can guarantee @@ -3547,10 +3530,7 @@ static int __devinit workqueue_cpu_up_callback(struct notifier_block *nfb, case CPU_DOWN_FAILED: case CPU_ONLINE: - gcwq_claim_management_and_lock(gcwq); - gcwq->flags &= ~GCWQ_DISASSOCIATED; rebind_workers(gcwq); - gcwq_release_management_and_unlock(gcwq); break; } return NOTIFY_OK; -- 1.7.4.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
