There are two aims for get_online_cpus():
1) Protects cpumask_of_node(node). (CPUs should stay stable)
2) Protects the pwq-allocation and installation
But both aims are settled by other methods in previous patches:
cpumask_of_node(node) is replaced by wq_unbound_online_cpumask, and
the pwq-allocation and installation are changed to be protected by
wq_pool_mutex. Now the get_online_cpus() is no reason to exist,
remove it!
Signed-off-by: Lai Jiangshan <la...@cn.fujitsu.com>
---
kernel/workqueue.c | 15 ++-------------
1 files changed, 2 insertions(+), 13 deletions(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 9bc3a87..63a8000 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3776,13 +3776,6 @@ int apply_workqueue_attrs(struct workqueue_struct *wq,
*/
copy_workqueue_attrs(tmp_attrs, new_attrs);
- /*
- * CPUs should stay stable across pwq creations and installations.
- * Pin CPUs, determine the target cpumask for each node and create
- * pwqs accordingly.
- */
- get_online_cpus();
-
mutex_lock(&wq_pool_mutex);
/*
@@ -3827,7 +3820,6 @@ int apply_workqueue_attrs(struct workqueue_struct *wq,
mutex_unlock(&wq_pool_mutex);
- put_online_cpus();
ret = 0;
/* fall through */
out_free:
@@ -3842,7 +3834,6 @@ enomem_pwq:
if (pwq_tbl && pwq_tbl[node] != dfl_pwq)
free_unbound_pwq(pwq_tbl[node]);
mutex_unlock(&wq_pool_mutex);
- put_online_cpus();
enomem:
ret = -ENOMEM;
goto out_free;
@@ -3921,10 +3912,8 @@ static void wq_update_unbound_numa(struct
workqueue_struct *wq, int cpu)
}
/*
- * Install the new pwq. As this function is called only from CPU
- * hotplug callbacks and applying a new attrs is wrapped with
- * get/put_online_cpus(), @wq->unbound_attrs couldn't have changed
- * inbetween.
+ * Install the new pwq. As this function is called with wq_pool_mutex
+ * held, @wq->unbound_attrs couldn't have changed inbetween.
*/
mutex_lock(&wq->mutex);
old_pwq = numa_pwq_tbl_install(wq, node, pwq);
--
1.7.4.4
--
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