forked from luck/tmp_suning_uos_patched
[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: Chuck Lever <cel@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
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@ -137,6 +137,7 @@ struct rpc_xprt_ops {
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void (*connect)(struct rpc_task *task);
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int (*send_request)(struct rpc_task *task);
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void (*set_retrans_timeout)(struct rpc_task *task);
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void (*timer)(struct rpc_task *task);
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void (*close)(struct rpc_xprt *xprt);
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void (*destroy)(struct rpc_xprt *xprt);
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};
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@ -257,6 +258,7 @@ void xprt_set_retrans_timeout_rtt(struct rpc_task *task);
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void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);
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void xprt_wait_for_buffer_space(struct rpc_task *task);
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void xprt_write_space(struct rpc_xprt *xprt);
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void xprt_adjust_cwnd(struct rpc_task *task, int result);
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struct rpc_rqst * xprt_lookup_rqst(struct rpc_xprt *xprt, u32 xid);
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void xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied);
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void xprt_disconnect(struct rpc_xprt *xprt);
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@ -289,16 +289,19 @@ __xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req)
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__xprt_lock_write_next_cong(xprt);
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}
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/*
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* Adjust RPC congestion window
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/**
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* xprt_adjust_cwnd - adjust transport congestion window
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* @task: recently completed RPC request used to adjust window
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* @result: result code of completed RPC request
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*
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* We use a time-smoothed congestion estimator to avoid heavy oscillation.
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*/
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static void
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xprt_adjust_cwnd(struct rpc_xprt *xprt, int result)
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void xprt_adjust_cwnd(struct rpc_task *task, int result)
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{
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unsigned long cwnd;
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struct rpc_rqst *req = task->tk_rqstp;
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struct rpc_xprt *xprt = task->tk_xprt;
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unsigned long cwnd = xprt->cwnd;
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cwnd = xprt->cwnd;
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if (result >= 0 && cwnd <= xprt->cong) {
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/* The (cwnd >> 1) term makes sure
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* the result gets rounded properly. */
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@ -314,6 +317,7 @@ xprt_adjust_cwnd(struct rpc_xprt *xprt, int result)
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dprintk("RPC: cong %ld, cwnd was %ld, now %ld\n",
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xprt->cong, xprt->cwnd, cwnd);
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xprt->cwnd = cwnd;
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__xprt_put_cong(xprt, req);
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}
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/**
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@ -602,8 +606,7 @@ void xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied)
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/* Adjust congestion window */
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if (!xprt->nocong) {
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unsigned timer = task->tk_msg.rpc_proc->p_timer;
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xprt_adjust_cwnd(xprt, copied);
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__xprt_put_cong(xprt, req);
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xprt_adjust_cwnd(task, copied);
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if (timer) {
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if (req->rq_ntrans == 1)
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rpc_update_rtt(clnt->cl_rtt, timer,
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@ -640,27 +643,19 @@ void xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied)
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return;
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}
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/*
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* RPC receive timeout handler.
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*/
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static void
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xprt_timer(struct rpc_task *task)
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static void xprt_timer(struct rpc_task *task)
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{
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struct rpc_rqst *req = task->tk_rqstp;
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struct rpc_rqst *req = task->tk_rqstp;
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struct rpc_xprt *xprt = req->rq_xprt;
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dprintk("RPC: %4d xprt_timer\n", task->tk_pid);
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spin_lock(&xprt->transport_lock);
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if (req->rq_received)
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goto out;
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xprt_adjust_cwnd(req->rq_xprt, -ETIMEDOUT);
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__xprt_put_cong(xprt, req);
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dprintk("RPC: %4d xprt_timer (%s request)\n",
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task->tk_pid, req ? "pending" : "backlogged");
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task->tk_status = -ETIMEDOUT;
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out:
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if (!req->rq_received) {
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if (xprt->ops->timer)
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xprt->ops->timer(task);
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task->tk_status = -ETIMEDOUT;
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}
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task->tk_timeout = 0;
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rpc_wake_up_task(task);
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spin_unlock(&xprt->transport_lock);
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@ -860,6 +860,17 @@ static void xs_tcp_set_buffer_size(struct rpc_xprt *xprt)
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return;
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}
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/**
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* xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
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* @task: task that timed out
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*
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* Adjust the congestion window after a retransmit timeout has occurred.
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*/
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static void xs_udp_timer(struct rpc_task *task)
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{
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xprt_adjust_cwnd(task, -ETIMEDOUT);
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}
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static int xs_bindresvport(struct rpc_xprt *xprt, struct socket *sock)
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{
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struct sockaddr_in myaddr = {
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@ -1050,6 +1061,7 @@ static struct rpc_xprt_ops xs_udp_ops = {
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.connect = xs_connect,
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.send_request = xs_udp_send_request,
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.set_retrans_timeout = xprt_set_retrans_timeout_rtt,
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.timer = xs_udp_timer,
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.close = xs_close,
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.destroy = xs_destroy,
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};
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