Commit 2abd2de7 authored by Andrew Hall's avatar Andrew Hall Committed by Alexei Starovoitov
Browse files

nbd: add tracepoints for send/receive timing 



This adds four tracepoints to nbd, enabling separate tracing of payload
and header sending/receipt.

In the send path for headers that have already been sent, we also
explicitly initialize the handle so it can be referenced by the later
tracepoint.

Signed-off-by: default avatarAndrew Hall <hall@fb.com>
Signed-off-by: default avatarMatt Mullins <mmullins@fb.com>
Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent ea106722

drivers/block/nbd.c

+8 −0
Original line number Diff line number Diff line
@@ -513,6 +513,10 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) 
	if (sent) {

		if (sent >= sizeof(request)) {

			skip = sent - sizeof(request);



			/* initialize handle for tracing purposes */

			handle = nbd_cmd_handle(cmd);



			goto send_pages;

		}

		iov_iter_advance(&from, sent);
@@ -536,6 +540,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) 
		(unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));

	result = sock_xmit(nbd, index, 1, &from,

			(type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);

	trace_nbd_header_sent(req, handle);

	if (result <= 0) {

		if (was_interrupted(result)) {

			/* If we havne't sent anything we can just return BUSY,
@@ -608,6 +613,7 @@ send_pages: 
		bio = next;

	}

out:

	trace_nbd_payload_sent(req, handle);

	nsock->pending = NULL;

	nsock->sent = 0;

	return 0;
@@ -655,6 +661,7 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index) 
			tag, req);

		return ERR_PTR(-ENOENT);

	}

	trace_nbd_header_received(req, handle);

	cmd = blk_mq_rq_to_pdu(req);



	mutex_lock(&cmd->lock);
@@ -708,6 +715,7 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index) 
		}

	}

out:

	trace_nbd_payload_received(req, handle);

	mutex_unlock(&cmd->lock);

	return ret ? ERR_PTR(ret) : cmd;

}

include/trace/events/nbd.h

+51 −0
Original line number Diff line number Diff line
@@ -7,6 +7,57 @@ 


#include <linux/tracepoint.h>



DECLARE_EVENT_CLASS(nbd_transport_event,



	TP_PROTO(struct request *req, u64 handle),



	TP_ARGS(req, handle),



	TP_STRUCT__entry(

		__field(struct request *, req)

		__field(u64, handle)

	),



	TP_fast_assign(

		__entry->req = req;

		__entry->handle = handle;

	),



	TP_printk(

		"nbd transport event: request %p, handle 0x%016llx",

		__entry->req,

		__entry->handle

	)

);



DEFINE_EVENT(nbd_transport_event, nbd_header_sent,



	TP_PROTO(struct request *req, u64 handle),



	TP_ARGS(req, handle)

);



DEFINE_EVENT(nbd_transport_event, nbd_payload_sent,



	TP_PROTO(struct request *req, u64 handle),



	TP_ARGS(req, handle)

);



DEFINE_EVENT(nbd_transport_event, nbd_header_received,



	TP_PROTO(struct request *req, u64 handle),



	TP_ARGS(req, handle)

);



DEFINE_EVENT(nbd_transport_event, nbd_payload_received,



	TP_PROTO(struct request *req, u64 handle),



	TP_ARGS(req, handle)

);



DECLARE_EVENT_CLASS(nbd_send_request,



	TP_PROTO(struct nbd_request *nbd_request, int index,

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