Commit 36df9aae authored by Trond Myklebust's avatar Trond Myklebust
Browse files

SUNRPC: Add a timer function to wait queues. 



This is designed to replace the timeout timer in the individual rpc_tasks.
By putting the timer function in the wait queue, we will eventually be able
to reduce the total number of timers in use by the RPC subsystem.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent f6a1cc89

include/linux/sunrpc/sched.h

+9 −0
Original line number Diff line number Diff line
@@ -33,6 +33,8 @@ struct rpc_wait_queue; 
struct rpc_wait {

	struct list_head	list;		/* wait queue links */

	struct list_head	links;		/* Links to related tasks */

	struct list_head	timer_list;	/* Timer list */

	unsigned long		expires;

};



/*
@@ -191,6 +193,12 @@ struct rpc_task_setup { 
#define RPC_PRIORITY_HIGH	(1)

#define RPC_NR_PRIORITY		(1 + RPC_PRIORITY_HIGH - RPC_PRIORITY_LOW)



struct rpc_timer {

	struct timer_list timer;

	struct list_head list;

	unsigned long expires;

};



/*

 * RPC synchronization objects

 */
@@ -203,6 +211,7 @@ struct rpc_wait_queue { 
	unsigned char		count;			/* # task groups remaining serviced so far */

	unsigned char		nr;			/* # tasks remaining for cookie */

	unsigned short		qlen;			/* total # tasks waiting in queue */

	struct rpc_timer	timer_list;

#ifdef RPC_DEBUG

	const char *		name;

#endif

net/sunrpc/sched.c

+42 −4
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ static mempool_t *rpc_buffer_mempool __read_mostly; 


static void			rpc_async_schedule(struct work_struct *);

static void			 rpc_release_task(struct rpc_task *task);

static void __rpc_queue_timer_fn(unsigned long ptr);



/*

 * RPC tasks sit here while waiting for conditions to improve.
@@ -59,8 +60,18 @@ struct workqueue_struct *rpciod_workqueue; 
static void

__rpc_disable_timer(struct rpc_task *task)

{

	if (task->tk_timeout == 0)

		return;

	dprintk("RPC: %5u disabling timer\n", task->tk_pid);

	task->tk_timeout = 0;

	list_del(&task->u.tk_wait.timer_list);

}



static void

rpc_set_queue_timer(struct rpc_wait_queue *queue, unsigned long expires)

{

	queue->timer_list.expires = expires;

	mod_timer(&queue->timer_list.timer, expires);

}



/*
@@ -153,7 +164,6 @@ static void __rpc_remove_wait_queue_priority(struct rpc_task *task) 
		list_move(&t->u.tk_wait.list, &task->u.tk_wait.list);

		list_splice_init(&task->u.tk_wait.links, &t->u.tk_wait.links);

	}

	list_del(&task->u.tk_wait.list);

}



/*
@@ -162,9 +172,9 @@ static void __rpc_remove_wait_queue_priority(struct rpc_task *task) 
 */

static void __rpc_remove_wait_queue(struct rpc_wait_queue *queue, struct rpc_task *task)

{

	__rpc_disable_timer(task);

	if (RPC_IS_PRIORITY(queue))

		__rpc_remove_wait_queue_priority(task);

	else

	list_del(&task->u.tk_wait.list);

	queue->qlen--;

	dprintk("RPC: %5u removed from queue %p \"%s\"\n",
@@ -198,6 +208,9 @@ static void __rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const c 
		INIT_LIST_HEAD(&queue->tasks[i]);

	queue->maxpriority = nr_queues - 1;

	rpc_reset_waitqueue_priority(queue);

	queue->qlen = 0;

	setup_timer(&queue->timer_list.timer, __rpc_queue_timer_fn, (unsigned long)queue);

	INIT_LIST_HEAD(&queue->timer_list.list);

#ifdef RPC_DEBUG

	queue->name = qname;

#endif
@@ -216,6 +229,7 @@ EXPORT_SYMBOL_GPL(rpc_init_wait_queue); 


void rpc_destroy_wait_queue(struct rpc_wait_queue *queue)

{

	del_timer_sync(&queue->timer_list.timer);

}

EXPORT_SYMBOL_GPL(rpc_destroy_wait_queue);
@@ -369,7 +383,6 @@ static void __rpc_do_wake_up_task(struct rpc_wait_queue *queue, struct rpc_task 
		return;

	}



	__rpc_disable_timer(task);

	__rpc_remove_wait_queue(queue, task);



	rpc_make_runnable(task);
@@ -562,6 +575,31 @@ static void rpc_run_timer(unsigned long ptr) 
	smp_mb__after_clear_bit();

}



static void __rpc_queue_timer_fn(unsigned long ptr)

{

	struct rpc_wait_queue *queue = (struct rpc_wait_queue *)ptr;

	struct rpc_task *task, *n;

	unsigned long expires, now, timeo;



	spin_lock(&queue->lock);

	expires = now = jiffies;

	list_for_each_entry_safe(task, n, &queue->timer_list.list, u.tk_wait.timer_list) {

		timeo = task->u.tk_wait.expires;

		if (time_after_eq(now, timeo)) {

			list_del_init(&task->u.tk_wait.timer_list);

			dprintk("RPC: %5u timeout\n", task->tk_pid);

			task->tk_status = -ETIMEDOUT;

			rpc_wake_up_task_queue_locked(queue, task);

			continue;

		}

		if (expires == now || time_after(expires, timeo))

			expires = timeo;

	}

	if (!list_empty(&queue->timer_list.list))

		rpc_set_queue_timer(queue, expires);

	spin_unlock(&queue->lock);

}



static void __rpc_atrun(struct rpc_task *task)

{

	task->tk_status = 0;

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