[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 <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index c9477f0..ac08e99 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -134,6 +134,7 @@
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 @@
/*
* 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
index 43fef762..1ac2fbe 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -275,6 +275,38 @@
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 @@
*/
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 @@
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 @@
}
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
index 5bb6fed..79433ff 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -1047,6 +1047,7 @@
.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 @@
.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,
};
