From: Chuck Lever <chuck.lever@oracle.com>
Date: Wed, 9 Oct 2019 12:58:14 -0400
Subject: SUNRPC: Add trace points to observe transport congestion control
Patch-mainline: v5.5-rc1
Git-commit: bf7ca707ae60045342e145c88a83bbe00f66775f
References: bsc#1154353
To help debug problems with RPC/RDMA credit management, replace
dprintk() call sites in the transport send lock paths with trace
events.
Similar trace points are defined for the non-congestion paths.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
include/trace/events/sunrpc.h | 93 ++++++++++++++++++++++++++++++++++++++++++
net/sunrpc/xprt.c | 22 +++++----
2 files changed, 106 insertions(+), 9 deletions(-)
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -777,6 +777,99 @@ TRACE_EVENT(xprt_ping,
__get_str(addr), __get_str(port), __entry->status)
);
+DECLARE_EVENT_CLASS(xprt_writelock_event,
+ TP_PROTO(
+ const struct rpc_xprt *xprt, const struct rpc_task *task
+ ),
+
+ TP_ARGS(xprt, task),
+
+ TP_STRUCT__entry(
+ __field(unsigned int, task_id)
+ __field(unsigned int, client_id)
+ __field(unsigned int, snd_task_id)
+ ),
+
+ TP_fast_assign(
+ if (task) {
+ __entry->task_id = task->tk_pid;
+ __entry->client_id = task->tk_client ?
+ task->tk_client->cl_clid : -1;
+ } else {
+ __entry->task_id = -1;
+ __entry->client_id = -1;
+ }
+ __entry->snd_task_id = xprt->snd_task ?
+ xprt->snd_task->tk_pid : -1;
+ ),
+
+ TP_printk("task:%u@%u snd_task:%u",
+ __entry->task_id, __entry->client_id,
+ __entry->snd_task_id)
+);
+
+#define DEFINE_WRITELOCK_EVENT(name) \
+ DEFINE_EVENT(xprt_writelock_event, xprt_##name, \
+ TP_PROTO( \
+ const struct rpc_xprt *xprt, \
+ const struct rpc_task *task \
+ ), \
+ TP_ARGS(xprt, task))
+
+DEFINE_WRITELOCK_EVENT(reserve_xprt);
+DEFINE_WRITELOCK_EVENT(release_xprt);
+
+DECLARE_EVENT_CLASS(xprt_cong_event,
+ TP_PROTO(
+ const struct rpc_xprt *xprt, const struct rpc_task *task
+ ),
+
+ TP_ARGS(xprt, task),
+
+ TP_STRUCT__entry(
+ __field(unsigned int, task_id)
+ __field(unsigned int, client_id)
+ __field(unsigned int, snd_task_id)
+ __field(unsigned long, cong)
+ __field(unsigned long, cwnd)
+ __field(bool, wait)
+ ),
+
+ TP_fast_assign(
+ if (task) {
+ __entry->task_id = task->tk_pid;
+ __entry->client_id = task->tk_client ?
+ task->tk_client->cl_clid : -1;
+ } else {
+ __entry->task_id = -1;
+ __entry->client_id = -1;
+ }
+ __entry->snd_task_id = xprt->snd_task ?
+ xprt->snd_task->tk_pid : -1;
+ __entry->cong = xprt->cong;
+ __entry->cwnd = xprt->cwnd;
+ __entry->wait = test_bit(XPRT_CWND_WAIT, &xprt->state);
+ ),
+
+ TP_printk("task:%u@%u snd_task:%u cong=%lu cwnd=%lu%s",
+ __entry->task_id, __entry->client_id,
+ __entry->snd_task_id, __entry->cong, __entry->cwnd,
+ __entry->wait ? " (wait)" : "")
+);
+
+#define DEFINE_CONG_EVENT(name) \
+ DEFINE_EVENT(xprt_cong_event, xprt_##name, \
+ TP_PROTO( \
+ const struct rpc_xprt *xprt, \
+ const struct rpc_task *task \
+ ), \
+ TP_ARGS(xprt, task))
+
+DEFINE_CONG_EVENT(reserve_cong);
+DEFINE_CONG_EVENT(release_cong);
+DEFINE_CONG_EVENT(get_cong);
+DEFINE_CONG_EVENT(put_cong);
+
TRACE_EVENT(xs_stream_read_data,
TP_PROTO(struct rpc_xprt *xprt, ssize_t err, size_t total),
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -205,20 +205,20 @@ int xprt_reserve_xprt(struct rpc_xprt *x
if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
if (task == xprt->snd_task)
- return 1;
+ goto out_locked;
goto out_sleep;
}
if (test_bit(XPRT_WRITE_SPACE, &xprt->state))
goto out_unlock;
xprt->snd_task = task;
+out_locked:
+ trace_xprt_reserve_xprt(xprt, task);
return 1;
out_unlock:
xprt_clear_locked(xprt);
out_sleep:
- dprintk("RPC: %5u failed to lock transport %p\n",
- task->tk_pid, xprt);
task->tk_status = -EAGAIN;
if (RPC_IS_SOFT(task))
rpc_sleep_on_timeout(&xprt->sending, task, NULL,
@@ -269,23 +269,22 @@ int xprt_reserve_xprt_cong(struct rpc_xp
if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
if (task == xprt->snd_task)
- return 1;
+ goto out_locked;
goto out_sleep;
}
if (req == NULL) {
xprt->snd_task = task;
- return 1;
+ goto out_locked;
}
if (test_bit(XPRT_WRITE_SPACE, &xprt->state))
goto out_unlock;
if (!xprt_need_congestion_window_wait(xprt)) {
xprt->snd_task = task;
- return 1;
+ goto out_locked;
}
out_unlock:
xprt_clear_locked(xprt);
out_sleep:
- dprintk("RPC: %5u failed to lock transport %p\n", task->tk_pid, xprt);
task->tk_status = -EAGAIN;
if (RPC_IS_SOFT(task))
rpc_sleep_on_timeout(&xprt->sending, task, NULL,
@@ -293,6 +292,9 @@ out_sleep:
else
rpc_sleep_on(&xprt->sending, task, NULL);
return 0;
+out_locked:
+ trace_xprt_reserve_cong(xprt, task);
+ return 1;
}
EXPORT_SYMBOL_GPL(xprt_reserve_xprt_cong);
@@ -357,6 +359,7 @@ void xprt_release_xprt(struct rpc_xprt *
xprt_clear_locked(xprt);
__xprt_lock_write_next(xprt);
}
+ trace_xprt_release_xprt(xprt, task);
}
EXPORT_SYMBOL_GPL(xprt_release_xprt);
@@ -374,6 +377,7 @@ void xprt_release_xprt_cong(struct rpc_x
xprt_clear_locked(xprt);
__xprt_lock_write_next_cong(xprt);
}
+ trace_xprt_release_cong(xprt, task);
}
EXPORT_SYMBOL_GPL(xprt_release_xprt_cong);
@@ -395,8 +399,7 @@ __xprt_get_cong(struct rpc_xprt *xprt, s
{
if (req->rq_cong)
return 1;
- dprintk("RPC: %5u xprt_cwnd_limited cong = %lu cwnd = %lu\n",
- req->rq_task->tk_pid, xprt->cong, xprt->cwnd);
+ trace_xprt_get_cong(xprt, req->rq_task);
if (RPCXPRT_CONGESTED(xprt)) {
xprt_set_congestion_window_wait(xprt);
return 0;
@@ -418,6 +421,7 @@ __xprt_put_cong(struct rpc_xprt *xprt, s
req->rq_cong = 0;
xprt->cong -= RPC_CWNDSCALE;
xprt_test_and_clear_congestion_window_wait(xprt);
+ trace_xprt_put_cong(xprt, req->rq_task);
__xprt_lock_write_next_cong(xprt);
}