[PATCH 09/10 V2] workqueue: separate pool-attaching code out from create_worker()

Lai Jiangshan
2014-05-12T06:53:37Z

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@cn.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