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authorLai Jiangshan <laijs@cn.fujitsu.com>2015-05-19 18:03:47 +0800
committerTejun Heo <tj@kernel.org>2015-05-19 17:37:00 -0400
commita0111cf6710bd1b4145ef313d3f4772602af051b (patch)
tree21acf858096755c322754314519dd04d2c8ed335 /kernel/workqueue.c
parentf7142ed483f49f9108bea1be0c1afcd5d9098e05 (diff)
downloadlinux-sh-a0111cf6710bd1b4145ef313d3f4772602af051b.tar.gz
workqueue: separate out and refactor the locking of applying attrs
Applying attrs requires two locks: get_online_cpus() and wq_pool_mutex, and this code is duplicated at two places (apply_workqueue_attrs() and workqueue_set_unbound_cpumask()). So we separate out this locking code into apply_wqattrs_[un]lock() and do a minor refactor on apply_workqueue_attrs(). The apply_wqattrs_[un]lock() will be also used on later patch for ensuring attrs changes are properly synchronized. tj: minor updates to comments Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/workqueue.c')
-rw-r--r--kernel/workqueue.c78
1 files changed, 45 insertions, 33 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 4a9f65b54ee5..72c1adbf7632 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3621,24 +3621,21 @@ static void apply_wqattrs_commit(struct apply_wqattrs_ctx *ctx)
mutex_unlock(&ctx->wq->mutex);
}
-/**
- * apply_workqueue_attrs - apply new workqueue_attrs to an unbound workqueue
- * @wq: the target workqueue
- * @attrs: the workqueue_attrs to apply, allocated with alloc_workqueue_attrs()
- *
- * Apply @attrs to an unbound workqueue @wq. Unless disabled, on NUMA
- * machines, this function maps a separate pwq to each NUMA node with
- * possibles CPUs in @attrs->cpumask so that work items are affine to the
- * NUMA node it was issued on. Older pwqs are released as in-flight work
- * items finish. Note that a work item which repeatedly requeues itself
- * back-to-back will stay on its current pwq.
- *
- * Performs GFP_KERNEL allocations.
- *
- * Return: 0 on success and -errno on failure.
- */
-int apply_workqueue_attrs(struct workqueue_struct *wq,
- const struct workqueue_attrs *attrs)
+static void apply_wqattrs_lock(void)
+{
+ /* CPUs should stay stable across pwq creations and installations */
+ get_online_cpus();
+ mutex_lock(&wq_pool_mutex);
+}
+
+static void apply_wqattrs_unlock(void)
+{
+ mutex_unlock(&wq_pool_mutex);
+ put_online_cpus();
+}
+
+static int apply_workqueue_attrs_locked(struct workqueue_struct *wq,
+ const struct workqueue_attrs *attrs)
{
struct apply_wqattrs_ctx *ctx;
int ret = -ENOMEM;
@@ -3651,14 +3648,6 @@ int apply_workqueue_attrs(struct workqueue_struct *wq,
if (WARN_ON((wq->flags & __WQ_ORDERED) && !list_empty(&wq->pwqs)))
return -EINVAL;
- /*
- * 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);
-
ctx = apply_wqattrs_prepare(wq, attrs);
/* the ctx has been prepared successfully, let's commit it */
@@ -3667,15 +3656,40 @@ int apply_workqueue_attrs(struct workqueue_struct *wq,
ret = 0;
}
- mutex_unlock(&wq_pool_mutex);
- put_online_cpus();
-
apply_wqattrs_cleanup(ctx);
return ret;
}
/**
+ * apply_workqueue_attrs - apply new workqueue_attrs to an unbound workqueue
+ * @wq: the target workqueue
+ * @attrs: the workqueue_attrs to apply, allocated with alloc_workqueue_attrs()
+ *
+ * Apply @attrs to an unbound workqueue @wq. Unless disabled, on NUMA
+ * machines, this function maps a separate pwq to each NUMA node with
+ * possibles CPUs in @attrs->cpumask so that work items are affine to the
+ * NUMA node it was issued on. Older pwqs are released as in-flight work
+ * items finish. Note that a work item which repeatedly requeues itself
+ * back-to-back will stay on its current pwq.
+ *
+ * Performs GFP_KERNEL allocations.
+ *
+ * Return: 0 on success and -errno on failure.
+ */
+int apply_workqueue_attrs(struct workqueue_struct *wq,
+ const struct workqueue_attrs *attrs)
+{
+ int ret;
+
+ apply_wqattrs_lock();
+ ret = apply_workqueue_attrs_locked(wq, attrs);
+ apply_wqattrs_unlock();
+
+ return ret;
+}
+
+/**
* wq_update_unbound_numa - update NUMA affinity of a wq for CPU hot[un]plug
* @wq: the target workqueue
* @cpu: the CPU coming up or going down
@@ -4799,10 +4813,9 @@ int workqueue_set_unbound_cpumask(cpumask_var_t cpumask)
if (!zalloc_cpumask_var(&saved_cpumask, GFP_KERNEL))
return -ENOMEM;
- get_online_cpus();
cpumask_and(cpumask, cpumask, cpu_possible_mask);
if (!cpumask_empty(cpumask)) {
- mutex_lock(&wq_pool_mutex);
+ apply_wqattrs_lock();
/* save the old wq_unbound_cpumask. */
cpumask_copy(saved_cpumask, wq_unbound_cpumask);
@@ -4815,9 +4828,8 @@ int workqueue_set_unbound_cpumask(cpumask_var_t cpumask)
if (ret < 0)
cpumask_copy(wq_unbound_cpumask, saved_cpumask);
- mutex_unlock(&wq_pool_mutex);
+ apply_wqattrs_unlock();
}
- put_online_cpus();
free_cpumask_var(saved_cpumask);
return ret;