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Commit 46c0ee8b authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
Browse files

[PATCH] RPC: separate xprt_timer implementations 



 Allow transports to hook the retransmit timer interrupt.  Some transports
 calculate their congestion window here so that a retransmit timeout has
 immediate effect on the congestion window.

 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 49e9a890

include/linux/sunrpc/xprt.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -137,6 +137,7 @@ struct rpc_xprt_ops { 
	void		(*connect)(struct rpc_task *task);

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

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

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

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

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

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

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

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

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

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

};

};
@@ -257,6 +258,7 @@ void xprt_set_retrans_timeout_rtt(struct rpc_task *task); 
void			xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);

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

void			xprt_wait_for_buffer_space(struct rpc_task *task);

void			xprt_wait_for_buffer_space(struct rpc_task *task);

void			xprt_write_space(struct rpc_xprt *xprt);

void			xprt_write_space(struct rpc_xprt *xprt);

void			xprt_adjust_cwnd(struct rpc_task *task, int result);

struct rpc_rqst *	xprt_lookup_rqst(struct rpc_xprt *xprt, u32 xid);

struct rpc_rqst *	xprt_lookup_rqst(struct rpc_xprt *xprt, u32 xid);

void			xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied);

void			xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied);

void			xprt_disconnect(struct rpc_xprt *xprt);

void			xprt_disconnect(struct rpc_xprt *xprt);

net/sunrpc/xprt.c

+20 −25
Original line number Original line Diff line number Diff line
@@ -289,16 +289,19 @@ __xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req) 
	__xprt_lock_write_next_cong(xprt);

	__xprt_lock_write_next_cong(xprt);

}

}





/*

/**

 * Adjust RPC congestion window

 * xprt_adjust_cwnd - adjust transport congestion window

 * @task: recently completed RPC request used to adjust window

 * @result: result code of completed RPC request

 *

 * We use a time-smoothed congestion estimator to avoid heavy oscillation.

 * We use a time-smoothed congestion estimator to avoid heavy oscillation.

 */

 */

static void

void xprt_adjust_cwnd(struct rpc_task *task, int result)

xprt_adjust_cwnd(struct rpc_xprt *xprt, int result)

{

{

	unsigned long	cwnd;

	struct rpc_rqst *req = task->tk_rqstp;

	struct rpc_xprt *xprt = task->tk_xprt;

	unsigned long cwnd = xprt->cwnd;





	cwnd = xprt->cwnd;

	if (result >= 0 && cwnd <= xprt->cong) {

	if (result >= 0 && cwnd <= xprt->cong) {

		/* The (cwnd >> 1) term makes sure

		/* The (cwnd >> 1) term makes sure

		 * the result gets rounded properly. */

		 * the result gets rounded properly. */
@@ -314,6 +317,7 @@ xprt_adjust_cwnd(struct rpc_xprt *xprt, int result) 
	dprintk("RPC:      cong %ld, cwnd was %ld, now %ld\n",

	dprintk("RPC:      cong %ld, cwnd was %ld, now %ld\n",

			xprt->cong, xprt->cwnd, cwnd);

			xprt->cong, xprt->cwnd, cwnd);

	xprt->cwnd = cwnd;

	xprt->cwnd = cwnd;

	__xprt_put_cong(xprt, req);

}

}





/**

/**
@@ -602,8 +606,7 @@ void xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied) 
	/* Adjust congestion window */

	/* Adjust congestion window */

	if (!xprt->nocong) {

	if (!xprt->nocong) {

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

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

		xprt_adjust_cwnd(xprt, copied);

		xprt_adjust_cwnd(task, copied);

		__xprt_put_cong(xprt, req);

		if (timer) {

		if (timer) {

			if (req->rq_ntrans == 1)

			if (req->rq_ntrans == 1)

				rpc_update_rtt(clnt->cl_rtt, timer,

				rpc_update_rtt(clnt->cl_rtt, timer,
@@ -640,27 +643,19 @@ void xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied) 
	return;

	return;

}

}





/*

static void xprt_timer(struct rpc_task *task)

 * RPC receive timeout handler.

 */

static void

xprt_timer(struct rpc_task *task)

{

{

	struct rpc_rqst *req = task->tk_rqstp;

	struct rpc_rqst *req = task->tk_rqstp;

	struct rpc_xprt *xprt = req->rq_xprt;

	struct rpc_xprt *xprt = req->rq_xprt;





	spin_lock(&xprt->transport_lock);

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

	if (req->rq_received)

		goto out;



	xprt_adjust_cwnd(req->rq_xprt, -ETIMEDOUT);

	__xprt_put_cong(xprt, req);



	dprintk("RPC: %4d xprt_timer (%s request)\n",

		task->tk_pid, req ? "pending" : "backlogged");





	spin_lock(&xprt->transport_lock);

	if (!req->rq_received) {

		if (xprt->ops->timer)

			xprt->ops->timer(task);

		task->tk_status = -ETIMEDOUT;

		task->tk_status = -ETIMEDOUT;

out:

	}

	task->tk_timeout = 0;

	task->tk_timeout = 0;

	rpc_wake_up_task(task);

	rpc_wake_up_task(task);

	spin_unlock(&xprt->transport_lock);

	spin_unlock(&xprt->transport_lock);

net/sunrpc/xprtsock.c

+12 −0
Original line number Original line Diff line number Diff line
@@ -860,6 +860,17 @@ static void xs_tcp_set_buffer_size(struct rpc_xprt *xprt) 
	return;

	return;

}

}





/**

 * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport

 * @task: task that timed out

 *

 * Adjust the congestion window after a retransmit timeout has occurred.

 */

static void xs_udp_timer(struct rpc_task *task)

{

	xprt_adjust_cwnd(task, -ETIMEDOUT);

}



static int xs_bindresvport(struct rpc_xprt *xprt, struct socket *sock)

static int xs_bindresvport(struct rpc_xprt *xprt, struct socket *sock)

{

{

	struct sockaddr_in myaddr = {

	struct sockaddr_in myaddr = {
@@ -1050,6 +1061,7 @@ static struct rpc_xprt_ops xs_udp_ops = { 
	.connect		= xs_connect,

	.connect		= xs_connect,

	.send_request		= xs_udp_send_request,

	.send_request		= xs_udp_send_request,

	.set_retrans_timeout	= xprt_set_retrans_timeout_rtt,

	.set_retrans_timeout	= xprt_set_retrans_timeout_rtt,

	.timer			= xs_udp_timer,

	.close			= xs_close,

	.close			= xs_close,

	.destroy		= xs_destroy,

	.destroy		= xs_destroy,

};

};