[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: Chuck Lever Signed-off-by: Trond Myklebust --- include/linux/sunrpc/xprt.h | 3 ++ net/sunrpc/xprt.c | 67 +++++++++++++++++++++++++++++-------------- net/sunrpc/xprtsock.c | 2 + 3 files changed, 50 insertions(+), 22 deletions(-) diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -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_h /* * 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); diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -275,6 +275,38 @@ void xprt_write_space(struct rpc_xprt *x 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 @@ out_unlock: */ 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) diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -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, };