[PATCH v1 04/22] SUNRPC: Update debugging instrumentation in xprt_do_reserve()

Chuck Lever
2020-07-08T20:09:24Z

Replace a dprintk() with a tracepoint. The tracepoint marks the
point where an RPC request is assigned an XID.

Additional clean up: Remove trace_xprt_enq_xmit, which reports much
the same thing. That tracepoint was added for debugging commit
918f3c1fe83c ("SUNRPC: Improve latency for interactive tasks").

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
include/trace/events/sunrpc.h | 55 ++++++++++++++++++-----------------------
net/sunrpc/xprt.c | 8 +-----
2 files changed, 26 insertions(+), 37 deletions(-)

diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index ea61628b9deb..7ff40870d122 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -1031,37 +1031,6 @@ TRACE_EVENT(xprt_transmit,
__entry->seqno, __entry->status)
);

-TRACE_EVENT(xprt_enq_xmit,
- TP_PROTO(
- const struct rpc_task *task,
- int stage
- ),
-
- TP_ARGS(task, stage),
-
- TP_STRUCT__entry(
- __field(unsigned int, task_id)
- __field(unsigned int, client_id)
- __field(u32, xid)
- __field(u32, seqno)
- __field(int, stage)
- ),
-
- TP_fast_assign(
- __entry->task_id = task->tk_pid;
- __entry->client_id = task->tk_client ?
- task->tk_client->cl_clid : -1;
- __entry->xid = be32_to_cpu(task->tk_rqstp->rq_xid);
- __entry->seqno = task->tk_rqstp->rq_seqno;
- __entry->stage = stage;
- ),
-
- TP_printk(
- "task:%u@%u xid=0x%08x seqno=%u stage=%d",
- __entry->task_id, __entry->client_id, __entry->xid,
- __entry->seqno, __entry->stage)
-);
-
TRACE_EVENT(xprt_ping,
TP_PROTO(const struct rpc_xprt *xprt, int status),

@@ -1176,6 +1145,30 @@ DEFINE_CONG_EVENT(release_cong);
DEFINE_CONG_EVENT(get_cong);
DEFINE_CONG_EVENT(put_cong);

+TRACE_EVENT(xprt_reserve,
+ TP_PROTO(
+ const struct rpc_rqst *rqst
+ ),
+
+ TP_ARGS(rqst),
+
+ TP_STRUCT__entry(
+ __field(unsigned int, task_id)
+ __field(unsigned int, client_id)
+ __field(u32, xid)
+ ),
+
+ TP_fast_assign(
+ __entry->task_id = rqst->rq_task->tk_pid;
+ __entry->client_id = rqst->rq_task->tk_client->cl_clid;
+ __entry->xid = be32_to_cpu(rqst->rq_xid);
+ ),
+
+ TP_printk("task:%u@%u xid=0x%08x",
+ __entry->task_id, __entry->client_id, __entry->xid
+ )
+);
+
TRACE_EVENT(xs_stream_read_data,
TP_PROTO(struct rpc_xprt *xprt, ssize_t err, size_t total),

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 46db56e1aa38..cb5cf74105aa 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1258,7 +1258,6 @@ xprt_request_enqueue_transmit(struct rpc_task *task)
/* Note: req is added _before_ pos */
list_add_tail(&req->rq_xmit, &pos->rq_xmit);
INIT_LIST_HEAD(&req->rq_xmit2);
- trace_xprt_enq_xmit(task, 1);
goto out;
}
} else if (RPC_IS_SWAPPER(task)) {
@@ -1270,7 +1269,6 @@ xprt_request_enqueue_transmit(struct rpc_task *task)
/* Note: req is added _before_ pos */
list_add_tail(&req->rq_xmit, &pos->rq_xmit);
INIT_LIST_HEAD(&req->rq_xmit2);
- trace_xprt_enq_xmit(task, 2);
goto out;
}
} else if (!req->rq_seqno) {
@@ -1279,13 +1277,11 @@ xprt_request_enqueue_transmit(struct rpc_task *task)
continue;
list_add_tail(&req->rq_xmit2, &pos->rq_xmit2);
INIT_LIST_HEAD(&req->rq_xmit);
- trace_xprt_enq_xmit(task, 3);
goto out;
}
}
list_add_tail(&req->rq_xmit, &xprt->xmit_queue);
INIT_LIST_HEAD(&req->rq_xmit2);
- trace_xprt_enq_xmit(task, 4);
out:
set_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate);
spin_unlock(&xprt->queue_lock);
@@ -1736,8 +1732,8 @@ xprt_request_init(struct rpc_task *task)
req->rq_rcv_buf.bvec = NULL;
req->rq_release_snd_buf = NULL;
xprt_init_majortimeo(task, req);
- dprintk("RPC: %5u reserved req %p xid %08x\n", task->tk_pid,
- req, ntohl(req->rq_xid));
+
+ trace_xprt_reserve(req);
}

static void