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Commit fe3aca29 authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
Browse files

[PATCH] RPC: add API to set transport-specific timeouts 



 Prepare the way to remove the "xprt->nocong" variable by adding a callout
 to the RPC client transport switch API to handle setting RPC retransmit
 timeouts.

 Add a pair of generic helper functions that provide the ability to set a
 simple fixed timeout, or to set a timeout based on the state of a round-
 trip estimator.

 Test-plan:
 Use WAN simulation to cause sporadic bursty packet loss.  Look for significant
 regression in performance or client stability.

 Signed-off-by: default avatarChuck Lever <cel@netapp.com>
 Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 43118c29

include/linux/sunrpc/xprt.h

+3 −0
Original line number Diff line number Diff line
@@ -134,6 +134,7 @@ struct rpc_xprt_ops { 
	void		(*set_buffer_size)(struct rpc_xprt *xprt);

	void		(*connect)(struct rpc_task *task);

	int		(*send_request)(struct rpc_task *task);

	void		(*set_retrans_timeout)(struct rpc_task *task);

	void		(*close)(struct rpc_xprt *xprt);

	void		(*destroy)(struct rpc_xprt *xprt);

};
@@ -245,6 +246,8 @@ static inline u32 *xprt_skip_transport_header(struct rpc_xprt *xprt, u32 *p) 
/*

 * Transport switch helper functions

 */

void			xprt_set_retrans_timeout_def(struct rpc_task *task);

void			xprt_set_retrans_timeout_rtt(struct rpc_task *task);

void			xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);

void			xprt_wait_for_buffer_space(struct rpc_task *task);

void			xprt_write_space(struct rpc_xprt *xprt);

net/sunrpc/xprt.c

+45 −22
Original line number Diff line number Diff line
@@ -275,6 +275,38 @@ void xprt_write_space(struct rpc_xprt *xprt) 
	spin_unlock_bh(&xprt->transport_lock);

}



/**

 * xprt_set_retrans_timeout_def - set a request's retransmit timeout

 * @task: task whose timeout is to be set

 *

 * Set a request's retransmit timeout based on the transport's

 * default timeout parameters.  Used by transports that don't adjust

 * the retransmit timeout based on round-trip time estimation.

 */

void xprt_set_retrans_timeout_def(struct rpc_task *task)

{

	task->tk_timeout = task->tk_rqstp->rq_timeout;

}



/*

 * xprt_set_retrans_timeout_rtt - set a request's retransmit timeout

 * @task: task whose timeout is to be set

 * 

 * Set a request's retransmit timeout using the RTT estimator.

 */

void xprt_set_retrans_timeout_rtt(struct rpc_task *task)

{

	int timer = task->tk_msg.rpc_proc->p_timer;

	struct rpc_rtt *rtt = task->tk_client->cl_rtt;

	struct rpc_rqst *req = task->tk_rqstp;

	unsigned long max_timeout = req->rq_xprt->timeout.to_maxval;



	task->tk_timeout = rpc_calc_rto(rtt, timer);

	task->tk_timeout <<= rpc_ntimeo(rtt, timer) + req->rq_retries;

	if (task->tk_timeout > max_timeout || task->tk_timeout == 0)

		task->tk_timeout = max_timeout;

}



static void xprt_reset_majortimeo(struct rpc_rqst *req)

{

	struct rpc_timeout *to = &req->rq_xprt->timeout;
@@ -588,7 +620,6 @@ int xprt_prepare_transmit(struct rpc_task *task) 
 */

void xprt_transmit(struct rpc_task *task)

{

	struct rpc_clnt *clnt = task->tk_client;

	struct rpc_rqst	*req = task->tk_rqstp;

	struct rpc_xprt	*xprt = req->rq_xprt;

	int status;
@@ -613,8 +644,19 @@ void xprt_transmit(struct rpc_task *task) 
		return;



	status = xprt->ops->send_request(task);

	if (!status)

		goto out_receive;

	if (status == 0) {

		dprintk("RPC: %4d xmit complete\n", task->tk_pid);

		spin_lock_bh(&xprt->transport_lock);

		xprt->ops->set_retrans_timeout(task);

		/* Don't race with disconnect */

		if (!xprt_connected(xprt))

			task->tk_status = -ENOTCONN;

		else if (!req->rq_received)

			rpc_sleep_on(&xprt->pending, task, NULL, xprt_timer);

		__xprt_release_write(xprt, task);

		spin_unlock_bh(&xprt->transport_lock);

		return;

	}



	/* Note: at this point, task->tk_sleeping has not yet been set,

	 *	 hence there is no danger of the waking up task being put on
@@ -634,25 +676,6 @@ void xprt_transmit(struct rpc_task *task) 
	}

	xprt_release_write(xprt, task);

	return;

 out_receive:

	dprintk("RPC: %4d xmit complete\n", task->tk_pid);

	/* Set the task's receive timeout value */

	spin_lock_bh(&xprt->transport_lock);

	if (!xprt->nocong) {

		int timer = task->tk_msg.rpc_proc->p_timer;

		task->tk_timeout = rpc_calc_rto(clnt->cl_rtt, timer);

		task->tk_timeout <<= rpc_ntimeo(clnt->cl_rtt, timer) + req->rq_retries;

		if (task->tk_timeout > xprt->timeout.to_maxval || task->tk_timeout == 0)

			task->tk_timeout = xprt->timeout.to_maxval;

	} else

		task->tk_timeout = req->rq_timeout;

	/* Don't race with disconnect */

	if (!xprt_connected(xprt))

		task->tk_status = -ENOTCONN;

	else if (!req->rq_received)

		rpc_sleep_on(&xprt->pending, task, NULL, xprt_timer);

	__xprt_release_write(xprt, task);

	spin_unlock_bh(&xprt->transport_lock);

}



static inline void do_xprt_reserve(struct rpc_task *task)

net/sunrpc/xprtsock.c

+2 −0
Original line number Diff line number Diff line
@@ -1047,6 +1047,7 @@ static struct rpc_xprt_ops xs_udp_ops = { 
	.set_buffer_size	= xs_udp_set_buffer_size,

	.connect		= xs_connect,

	.send_request		= xs_udp_send_request,

	.set_retrans_timeout	= xprt_set_retrans_timeout_rtt,

	.close			= xs_close,

	.destroy		= xs_destroy,

};
@@ -1055,6 +1056,7 @@ static struct rpc_xprt_ops xs_tcp_ops = { 
	.set_buffer_size	= xs_tcp_set_buffer_size,

	.connect		= xs_connect,

	.send_request		= xs_tcp_send_request,

	.set_retrans_timeout	= xprt_set_retrans_timeout_def,

	.close			= xs_close,

	.destroy		= xs_destroy,

};