linux-kernel - [PATCH 09/10 V2] workqueue: separate pool-attaching code out from create

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Message-ID: <1399877792-13046-10-git-send-email-laijs@cn.fujitsu.com>
Date:	Mon, 12 May 2014 14:56:21 +0800
From:	Lai Jiangshan <laijs@...fujitsu.com>
To:	<linux-kernel@...r.kernel.org>
CC:	Tejun Heo <tj@...nel.org>, Lai Jiangshan <laijs@...fujitsu.com>
Subject: [PATCH 09/10 V2] workqueue: separate pool-attaching code out from create_worker()

The code of attaching is unfolded in create_worker().
Separating this code out will make the codes more clear.

Signed-off-by: Lai Jiangshan <laijs@...fujitsu.com>
---
 kernel/workqueue.c |   54 ++++++++++++++++++++++++++++++++-------------------
 1 files changed, 34 insertions(+), 20 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index e6d9725..0ea0152 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -66,7 +66,7 @@ enum {
 	 *
 	 * Note that DISASSOCIATED should be flipped only while holding
 	 * attach_mutex to avoid changing binding state while
-	 * create_worker() is in progress.
+	 * worker_attach_to_pool() is in progress.
 	 */
 	POOL_DISASSOCIATED	= 1 << 2,	/* cpu can't serve workers */
 	POOL_FREEZING		= 1 << 3,	/* freeze in progress */
@@ -1668,6 +1668,38 @@ static struct worker *alloc_worker(void)
 }
 
 /**
+ * worker_attach_to_pool() - attach the worker to the pool
+ * @worker: worker to be attached
+ * @pool: the target pool
+ *
+ * attach the worker to the pool, thus the concurrency and cpu-binding of
+ * the worker are kept coordination with the pool across cpu-[un]hotplug.
+ */
+static void worker_attach_to_pool(struct worker *worker,
+				   struct worker_pool *pool)
+{
+	mutex_lock(&pool->attach_mutex);
+
+	/*
+	 * set_cpus_allowed_ptr() will fail if the cpumask doesn't have any
+	 * online CPUs.  It'll be re-applied when any of the CPUs come up.
+	 */
+	set_cpus_allowed_ptr(worker->task, pool->attrs->cpumask);
+
+	/*
+	 * The pool->attach_mutex ensures %POOL_DISASSOCIATED remains
+	 * stable across this function.  See the comments above the
+	 * flag definition for details.
+	 */
+	if (pool->flags & POOL_DISASSOCIATED)
+		worker->flags |= WORKER_UNBOUND;
+
+	list_add_tail(&worker->node, &pool->workers);
+
+	mutex_unlock(&pool->attach_mutex);
+}
+
+/**
  * worker_detach_from_pool() - detach the worker from the pool
  * @worker: worker which is attached to its pool
  * @pool: attached pool
@@ -1738,26 +1770,8 @@ static struct worker *create_worker(struct worker_pool *pool)
 	/* prevent userland from meddling with cpumask of workqueue workers */
 	worker->task->flags |= PF_NO_SETAFFINITY;
 
-	mutex_lock(&pool->attach_mutex);
-
-	/*
-	 * set_cpus_allowed_ptr() will fail if the cpumask doesn't have any
-	 * online CPUs.  It'll be re-applied when any of the CPUs come up.
-	 */
-	set_cpus_allowed_ptr(worker->task, pool->attrs->cpumask);
-
-	/*
-	 * The pool->attach_mutex ensures %POOL_DISASSOCIATED
-	 * remains stable across this function.  See the comments above the
-	 * flag definition for details.
-	 */
-	if (pool->flags & POOL_DISASSOCIATED)
-		worker->flags |= WORKER_UNBOUND;
-
 	/* successful, attach the worker to the pool */
-	list_add_tail(&worker->node, &pool->workers);
-
-	mutex_unlock(&pool->attach_mutex);
+	worker_attach_to_pool(worker, pool);
 
 	return worker;
 
-- 
1.7.4.4

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