because old busy_worker_rebind_fn() have to wait until all idle worker finish. so we have to use two flags WORKER_UNBOUND and WORKER_REBIND to avoid prematurely clear all NOT_RUNNING bit when highly frequent offline/online.
but current code don't need to wait idle workers nor release gcwq->lock when it is doing rebind in rebind_workers(), so we don't need to use two flags, just one is enough. remove WORKER_REBIND from busy rebinding. Signed-off-by: Lai Jiangshan <[email protected]> --- kernel/workqueue.c | 19 ++----------------- 1 files changed, 2 insertions(+), 17 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index dbc942e..6b643df 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1642,17 +1642,8 @@ static void busy_worker_rebind_fn(struct work_struct *work) struct worker *worker = container_of(work, struct worker, rebind_work); struct global_cwq *gcwq = worker->pool->gcwq; - worker_maybe_bind_and_lock(worker); - - /* - * If hotplug has happened after rebind_workers(), a new %UNBOUND will - * have been set in worker->flags, so we can clear WORKER_REBIND - * unconditionaly(even the above worker_maybe_bind_and_lock() failed). - * - * And we must clear this WORKER_REBIND before return, otherwise - * this worker may go to call idle_worker_rebind() wrongly. - */ - worker_clr_flags(worker, WORKER_REBIND); + if (worker_maybe_bind_and_lock(worker)) + worker_clr_flags(worker, WORKER_UNBOUND); spin_unlock_irq(&gcwq->lock); } @@ -1727,15 +1718,9 @@ static void rebind_workers(struct global_cwq *gcwq) /* rebind busy workers */ for_each_busy_worker(worker, i, pos, gcwq) { - unsigned long worker_flags = worker->flags; struct work_struct *rebind_work = &worker->rebind_work; struct workqueue_struct *wq; - /* morph UNBOUND to REBIND atomically */ - worker_flags &= ~WORKER_UNBOUND; - worker_flags |= WORKER_REBIND; - ACCESS_ONCE(worker->flags) = worker_flags; - if (test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(rebind_work))) continue; -- 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/
