linux-kernel - [PATCH 07/11 V5] workqueue: rebind manager

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Date:	Wed, 5 Sep 2012 18:37:44 +0800
From:	Lai Jiangshan <laijs@...fujitsu.com>
To:	Tejun Heo <tj@...nel.org>, linux-kernel@...r.kernel.org
Cc:	Lai Jiangshan <laijs@...fujitsu.com>
Subject: [PATCH 07/11 V5] workqueue: rebind manager

Because the %UNBOUND bit of manager can't be cleared while it
is manage workers. maybe_rebind_manager() will be noticed and
will do rebind when needed.

It just prepares, this code is useless until
"we unbind/rebind without manager_mutex"

Signed-off-by: Lai Jiangshan <laijs@...fujitsu.com>
---
 kernel/workqueue.c |   23 +++++++++++++++++++++++
 1 files changed, 23 insertions(+), 0 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 9f4dd20..e9fc065 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1540,6 +1540,14 @@ static void worker_leave_idle(struct worker *worker)
 	list_del_init(&worker->entry);
 }
 
+/* Does this worker need to be rebound */
+static bool need_to_rebind_worker(struct worker *worker)
+{
+	bool assoc = !(worker->pool->gcwq->flags & GCWQ_DISASSOCIATED);
+
+	return assoc && (worker->flags & WORKER_UNBOUND);
+}
+
 /**
  * worker_maybe_bind_and_lock - bind worker to its cpu if possible and lock gcwq
  * @worker: self
@@ -2028,6 +2036,20 @@ static bool maybe_destroy_workers(struct worker_pool *pool)
 	return ret;
 }
 
+static bool maybe_rebind_manager(struct worker *manager)
+{
+	if (unlikely(need_to_rebind_worker(manager))) {
+		spin_unlock_irq(&manager->pool->gcwq->lock);
+
+		if (worker_maybe_bind_and_lock(manager))
+			worker_clr_flags(manager, WORKER_UNBOUND);
+
+		return true;
+	}
+
+	return false;
+}
+
 /**
  * manage_workers - manage worker pool
  * @worker: self
@@ -2065,6 +2087,7 @@ static bool manage_workers(struct worker *worker)
 	 */
 	ret |= maybe_destroy_workers(pool);
 	ret |= maybe_create_worker(pool);
+	ret |= maybe_rebind_manager(worker);
 
 	mutex_unlock(&pool->manager_mutex);
 	pool->manager = NULL;
-- 
1.7.4.4

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