SUNRPC: Reduce latency when send queue is congested
Use the low latency transport workqueue to process the task that is
next in line on the xprt->sending queue.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index a9f7862..9ae5885 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -330,7 +330,8 @@
* lockless RPC_IS_QUEUED() test) before we've had a chance to test
* the RPC_TASK_RUNNING flag.
*/
-static void rpc_make_runnable(struct rpc_task *task)
+static void rpc_make_runnable(struct workqueue_struct *wq,
+ struct rpc_task *task)
{
bool need_wakeup = !rpc_test_and_set_running(task);
@@ -339,7 +340,7 @@
return;
if (RPC_IS_ASYNC(task)) {
INIT_WORK(&task->u.tk_work, rpc_async_schedule);
- queue_work(rpciod_workqueue, &task->u.tk_work);
+ queue_work(wq, &task->u.tk_work);
} else
wake_up_bit(&task->tk_runstate, RPC_TASK_QUEUED);
}
@@ -408,13 +409,16 @@
EXPORT_SYMBOL_GPL(rpc_sleep_on_priority);
/**
- * __rpc_do_wake_up_task - wake up a single rpc_task
+ * __rpc_do_wake_up_task_on_wq - wake up a single rpc_task
+ * @wq: workqueue on which to run task
* @queue: wait queue
* @task: task to be woken up
*
* Caller must hold queue->lock, and have cleared the task queued flag.
*/
-static void __rpc_do_wake_up_task(struct rpc_wait_queue *queue, struct rpc_task *task)
+static void __rpc_do_wake_up_task_on_wq(struct workqueue_struct *wq,
+ struct rpc_wait_queue *queue,
+ struct rpc_task *task)
{
dprintk("RPC: %5u __rpc_wake_up_task (now %lu)\n",
task->tk_pid, jiffies);
@@ -429,7 +433,7 @@
__rpc_remove_wait_queue(queue, task);
- rpc_make_runnable(task);
+ rpc_make_runnable(wq, task);
dprintk("RPC: __rpc_wake_up_task done\n");
}
@@ -437,16 +441,25 @@
/*
* Wake up a queued task while the queue lock is being held
*/
-static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue *queue, struct rpc_task *task)
+static void rpc_wake_up_task_on_wq_queue_locked(struct workqueue_struct *wq,
+ struct rpc_wait_queue *queue, struct rpc_task *task)
{
if (RPC_IS_QUEUED(task)) {
smp_rmb();
if (task->tk_waitqueue == queue)
- __rpc_do_wake_up_task(queue, task);
+ __rpc_do_wake_up_task_on_wq(wq, queue, task);
}
}
/*
+ * Wake up a queued task while the queue lock is being held
+ */
+static void rpc_wake_up_task_queue_locked(struct rpc_wait_queue *queue, struct rpc_task *task)
+{
+ rpc_wake_up_task_on_wq_queue_locked(rpciod_workqueue, queue, task);
+}
+
+/*
* Wake up a task on a specific queue
*/
void rpc_wake_up_queued_task(struct rpc_wait_queue *queue, struct rpc_task *task)
@@ -519,7 +532,8 @@
/*
* Wake up the first task on the wait queue.
*/
-struct rpc_task *rpc_wake_up_first(struct rpc_wait_queue *queue,
+struct rpc_task *rpc_wake_up_first_on_wq(struct workqueue_struct *wq,
+ struct rpc_wait_queue *queue,
bool (*func)(struct rpc_task *, void *), void *data)
{
struct rpc_task *task = NULL;
@@ -530,7 +544,7 @@
task = __rpc_find_next_queued(queue);
if (task != NULL) {
if (func(task, data))
- rpc_wake_up_task_queue_locked(queue, task);
+ rpc_wake_up_task_on_wq_queue_locked(wq, queue, task);
else
task = NULL;
}
@@ -538,6 +552,15 @@
return task;
}
+
+/*
+ * Wake up the first task on the wait queue.
+ */
+struct rpc_task *rpc_wake_up_first(struct rpc_wait_queue *queue,
+ bool (*func)(struct rpc_task *, void *), void *data)
+{
+ return rpc_wake_up_first_on_wq(rpciod_workqueue, queue, func, data);
+}
EXPORT_SYMBOL_GPL(rpc_wake_up_first);
static bool rpc_wake_up_next_func(struct rpc_task *task, void *data)
@@ -815,7 +838,7 @@
bool is_async = RPC_IS_ASYNC(task);
rpc_set_active(task);
- rpc_make_runnable(task);
+ rpc_make_runnable(rpciod_workqueue, task);
if (!is_async)
__rpc_execute(task);
}