Factor out pool_workqueue linking and installation into numa_pwq_tbl[]
from apply_workqueue_attrs() into numa_pwq_tbl_install(). link_pwq()
is made safe to call multiple times. numa_pwq_tbl_install() links the
pwq, installs it into numa_pwq_tbl[] at the specified node and returns
the old entry.
@last_pwq is removed from link_pwq() as the return value of the new
function can be used instead.
This is to prepare for NUMA affinity support for unbound workqueues.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
---
kernel/workqueue.c | 35 ++++++++++++++++++++++++++---------
1 file changed, 26 insertions(+), 9 deletions(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index a4420be..527dc418 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3639,24 +3639,26 @@ static void init_pwq(struct pool_workqueue *pwq, struct workqueue_struct *wq,
pwq->flush_color = -1;
pwq->refcnt = 1;
INIT_LIST_HEAD(&pwq->delayed_works);
+ INIT_LIST_HEAD(&pwq->pwqs_node);
INIT_LIST_HEAD(&pwq->mayday_node);
INIT_WORK(&pwq->unbound_release_work, pwq_unbound_release_workfn);
}
/* sync @pwq with the current state of its associated wq and link it */
-static void link_pwq(struct pool_workqueue *pwq,
- struct pool_workqueue **p_last_pwq)
+static void link_pwq(struct pool_workqueue *pwq)
{
struct workqueue_struct *wq = pwq->wq;
lockdep_assert_held(&wq->mutex);
+ /* may be called multiple times, ignore if already linked */
+ if (!list_empty(&pwq->pwqs_node))
+ return;
+
/*
* Set the matching work_color. This is synchronized with
* wq->mutex to avoid confusing flush_workqueue().
*/
- if (p_last_pwq)
- *p_last_pwq = first_pwq(wq);
pwq->work_color = wq->work_color;
/* sync max_active to the current setting */
@@ -3689,6 +3691,23 @@ static struct pool_workqueue *alloc_unbound_pwq(struct workqueue_struct *wq,
return pwq;
}
+/* install @pwq into @wq's numa_pwq_tbl[] for @node and return the old pwq */
+static struct pool_workqueue *numa_pwq_tbl_install(struct workqueue_struct *wq,
+ int node,
+ struct pool_workqueue *pwq)
+{
+ struct pool_workqueue *old_pwq;
+
+ lockdep_assert_held(&wq->mutex);
+
+ /* link_pwq() can handle duplicate calls */
+ link_pwq(pwq);
+
+ old_pwq = rcu_access_pointer(wq->numa_pwq_tbl[node]);
+ rcu_assign_pointer(wq->numa_pwq_tbl[node], pwq);
+ return old_pwq;
+}
+
/**
* apply_workqueue_attrs - apply new workqueue_attrs to an unbound workqueue
* @wq: the target workqueue
@@ -3707,7 +3726,7 @@ int apply_workqueue_attrs(struct workqueue_struct *wq,
const struct workqueue_attrs *attrs)
{
struct workqueue_attrs *new_attrs;
- struct pool_workqueue *pwq, *last_pwq;
+ struct pool_workqueue *pwq, *last_pwq = NULL;
int node;
/* only unbound workqueues can change attributes */
@@ -3734,11 +3753,9 @@ int apply_workqueue_attrs(struct workqueue_struct *wq,
mutex_lock(&wq->mutex);
- link_pwq(pwq, &last_pwq);
-
copy_workqueue_attrs(wq->unbound_attrs, new_attrs);
for_each_node(node)
- rcu_assign_pointer(wq->numa_pwq_tbl[node], pwq);
+ last_pwq = numa_pwq_tbl_install(wq, node, pwq);
mutex_unlock(&wq->mutex);
@@ -3774,7 +3791,7 @@ static int alloc_and_link_pwqs(struct workqueue_struct *wq)
init_pwq(pwq, wq, &cpu_pools[highpri]);
mutex_lock(&wq->mutex);
- link_pwq(pwq, NULL);
+ link_pwq(pwq);
mutex_unlock(&wq->mutex);
}
return 0;
--
1.8.1.4
--
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