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Commit 1570c1e4 authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
Browse files

[PATCH] RPC: add generic interface for adjusting the congestion window 



 A new interface that allows transports to adjust their congestion window
 using the Van Jacobson implementation in xprt.c is provided.

 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 46c0ee8b

include/linux/sunrpc/xprt.h

+2 −1
Original line number Diff line number Diff line
@@ -258,9 +258,10 @@ 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);

void			xprt_update_rtt(struct rpc_task *task);

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

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_task *task, int copied);

void			xprt_disconnect(struct rpc_xprt *xprt);



/*

net/sunrpc/xprt.c

+26 −40
Original line number Diff line number Diff line
@@ -592,55 +592,41 @@ struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, u32 xid) 
}



/**

 * xprt_complete_rqst - called when reply processing is complete

 * @xprt: controlling transport

 * @req: RPC request that just completed

 * @copied: actual number of bytes received from the transport

 * xprt_update_rtt - update an RPC client's RTT state after receiving a reply

 * @task: RPC request that recently completed

 *

 */

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

void xprt_update_rtt(struct rpc_task *task)

{

	struct rpc_task	*task = req->rq_task;

	struct rpc_clnt *clnt = task->tk_client;



	/* Adjust congestion window */

	if (!xprt->nocong) {

	struct rpc_rqst *req = task->tk_rqstp;

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

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

		xprt_adjust_cwnd(task, copied);



	if (timer) {

		if (req->rq_ntrans == 1)

				rpc_update_rtt(clnt->cl_rtt, timer,

			rpc_update_rtt(rtt, timer,

					(long)jiffies - req->rq_xtime);

			rpc_set_timeo(clnt->cl_rtt, timer, req->rq_ntrans - 1);

		rpc_set_timeo(rtt, timer, req->rq_ntrans - 1);

	}

}



#ifdef RPC_PROFILE

	/* Profile only reads for now */

	if (copied > 1024) {

		static unsigned long	nextstat;

		static unsigned long	pkt_rtt, pkt_len, pkt_cnt;

/**

 * xprt_complete_rqst - called when reply processing is complete

 * @task: RPC request that recently completed

 * @copied: actual number of bytes received from the transport

 *

 * Caller holds transport lock.

 */

void xprt_complete_rqst(struct rpc_task *task, int copied)

{

	struct rpc_rqst *req = task->tk_rqstp;



		pkt_cnt++;

		pkt_len += req->rq_slen + copied;

		pkt_rtt += jiffies - req->rq_xtime;

		if (time_before(nextstat, jiffies)) {

			printk("RPC: %lu %ld cwnd\n", jiffies, xprt->cwnd);

			printk("RPC: %ld %ld %ld %ld stat\n",

					jiffies, pkt_cnt, pkt_len, pkt_rtt);

			pkt_rtt = pkt_len = pkt_cnt = 0;

			nextstat = jiffies + 5 * HZ;

		}

	}

#endif

	dprintk("RPC: %5u xid %08x complete (%d bytes received)\n",

			task->tk_pid, ntohl(req->rq_xid), copied);



	dprintk("RPC: %4d has input (%d bytes)\n", task->tk_pid, copied);

	list_del_init(&req->rq_list);

	req->rq_received = req->rq_private_buf.len = copied;



	/* ... and wake up the process. */

	rpc_wake_up_task(task);

	return;

}



static void xprt_timer(struct rpc_task *task)

net/sunrpc/xprtsock.c

+5 −8
Original line number Diff line number Diff line
@@ -460,8 +460,6 @@ static void xs_udp_data_ready(struct sock *sk, int len) 
		goto out_unlock;

	task = rovr->rq_task;



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



	if ((copied = rovr->rq_private_buf.buflen) > repsize)

		copied = repsize;
@@ -472,7 +470,9 @@ static void xs_udp_data_ready(struct sock *sk, int len) 
	/* Something worked... */

	dst_confirm(skb->dst);



	xprt_complete_rqst(xprt, rovr, copied);

	xprt_adjust_cwnd(task, copied);

	xprt_update_rtt(task);

	xprt_complete_rqst(task, copied);



 out_unlock:

	spin_unlock(&xprt->transport_lock);
@@ -634,11 +634,8 @@ static inline void xs_tcp_read_request(struct rpc_xprt *xprt, skb_reader_t *desc 
	}



out:

	if (!(xprt->tcp_flags & XPRT_COPY_DATA)) {

		dprintk("RPC: %4d received reply complete\n",

				req->rq_task->tk_pid);

		xprt_complete_rqst(xprt, req, xprt->tcp_copied);

	}

	if (!(xprt->tcp_flags & XPRT_COPY_DATA))

		xprt_complete_rqst(req->rq_task, xprt->tcp_copied);

	spin_unlock(&xprt->transport_lock);

	xs_tcp_check_recm(xprt);

}