From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Thu, 22 Oct 2020 17:40:33 -0400
Subject: [PATCH] SUNRPC: rpc_wake_up() should wake up tasks in the correct
order
Git-commit: e4c72201b6ec3173dfe13fa2e2335a3ad78d4921
Patch-mainline: v5.11-rc1
References: for-next
Currently, we wake up the tasks by priority queue ordering, which means
that we ignore the batching that is supposed to help with QoS issues.
Fixes: c049f8ea9a0d ("SUNRPC: Remove the bh-safe lock requirement on the rpc_wait_queue->lock")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Acked-by: NeilBrown <neilb@suse.com>
---
net/sunrpc/sched.c | 65 ++++++++++++++++++++++++++++-------------------------
1 file changed, 35 insertions(+), 30 deletions(-)
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -693,6 +693,23 @@ struct rpc_task *rpc_wake_up_next(struct
EXPORT_SYMBOL_GPL(rpc_wake_up_next);
/**
+ * rpc_wake_up_locked - wake up all rpc_tasks
+ * @queue: rpc_wait_queue on which the tasks are sleeping
+ *
+ */
+static void rpc_wake_up_locked(struct rpc_wait_queue *queue)
+{
+ struct rpc_task *task;
+
+ for (;;) {
+ task = __rpc_find_next_queued(queue);
+ if (task == NULL)
+ break;
+ rpc_wake_up_task_queue_locked(queue, task);
+ }
+}
+
+/**
* rpc_wake_up - wake up all rpc_tasks
* @queue: rpc_wait_queue on which the tasks are sleeping
*
@@ -700,25 +717,28 @@ EXPORT_SYMBOL_GPL(rpc_wake_up_next);
*/
void rpc_wake_up(struct rpc_wait_queue *queue)
{
- struct list_head *head;
-
spin_lock(&queue->lock);
- head = &queue->tasks[queue->maxpriority];
+ rpc_wake_up_locked(queue);
+ spin_unlock(&queue->lock);
+}
+EXPORT_SYMBOL_GPL(rpc_wake_up);
+
+/**
+ * rpc_wake_up_status_locked - wake up all rpc_tasks and set their status value.
+ * @queue: rpc_wait_queue on which the tasks are sleeping
+ * @status: status value to set
+ */
+static void rpc_wake_up_status_locked(struct rpc_wait_queue *queue, int status)
+{
+ struct rpc_task *task;
+
for (;;) {
- while (!list_empty(head)) {
- struct rpc_task *task;
- task = list_first_entry(head,
- struct rpc_task,
- u.tk_wait.list);
- rpc_wake_up_task_queue_locked(queue, task);
- }
- if (head == &queue->tasks[0])
+ task = __rpc_find_next_queued(queue);
+ if (task == NULL)
break;
- head--;
+ rpc_wake_up_task_queue_set_status_locked(queue, task, status);
}
- spin_unlock(&queue->lock);
}
-EXPORT_SYMBOL_GPL(rpc_wake_up);
/**
* rpc_wake_up_status - wake up all rpc_tasks and set their status value.
@@ -729,23 +749,8 @@ EXPORT_SYMBOL_GPL(rpc_wake_up);
*/
void rpc_wake_up_status(struct rpc_wait_queue *queue, int status)
{
- struct list_head *head;
-
spin_lock(&queue->lock);
- head = &queue->tasks[queue->maxpriority];
- for (;;) {
- while (!list_empty(head)) {
- struct rpc_task *task;
- task = list_first_entry(head,
- struct rpc_task,
- u.tk_wait.list);
- task->tk_status = status;
- rpc_wake_up_task_queue_locked(queue, task);
- }
- if (head == &queue->tasks[0])
- break;
- head--;
- }
+ rpc_wake_up_status_locked(queue, status);
spin_unlock(&queue->lock);
}
EXPORT_SYMBOL_GPL(rpc_wake_up_status);