Commit 4d843be5 authored by David Howells's avatar David Howells
Browse files

rxrpc: Trace setting of the request-ack flag 



Add a tracepoint to log why the request-ack flag is set on an outgoing DATA
packet, allowing debugging as to why.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
parent c3d96f69

include/trace/events/rxrpc.h

+36 −0
Original line number Diff line number Diff line
@@ -242,6 +242,16 @@ 
	EM(rxrpc_tx_point_version_keepalive,	"VerKeepalive") \

	E_(rxrpc_tx_point_version_reply,	"VerReply")



#define rxrpc_req_ack_traces \

	EM(rxrpc_reqack_ack_lost,		"ACK-LOST  ")	\

	EM(rxrpc_reqack_already_on,		"ALREADY-ON")	\

	EM(rxrpc_reqack_more_rtt,		"MORE-RTT  ")	\

	EM(rxrpc_reqack_no_srv_last,		"NO-SRVLAST")	\

	EM(rxrpc_reqack_old_rtt,		"OLD-RTT   ")	\

	EM(rxrpc_reqack_retrans,		"RETRANS   ")	\

	EM(rxrpc_reqack_slow_start,		"SLOW-START")	\

	E_(rxrpc_reqack_small_txwin,		"SMALL-TXWN")



/*

 * Generate enums for tracing information.

 */
@@ -263,6 +273,7 @@ enum rxrpc_propose_ack_outcome { rxrpc_propose_ack_outcomes } __mode(byte); 
enum rxrpc_propose_ack_trace	{ rxrpc_propose_ack_traces } __mode(byte);

enum rxrpc_receive_trace	{ rxrpc_receive_traces } __mode(byte);

enum rxrpc_recvmsg_trace	{ rxrpc_recvmsg_traces } __mode(byte);

enum rxrpc_req_ack_trace	{ rxrpc_req_ack_traces } __mode(byte);

enum rxrpc_rtt_rx_trace		{ rxrpc_rtt_rx_traces } __mode(byte);

enum rxrpc_rtt_tx_trace		{ rxrpc_rtt_tx_traces } __mode(byte);

enum rxrpc_skb_trace		{ rxrpc_skb_traces } __mode(byte);
@@ -290,6 +301,7 @@ rxrpc_propose_ack_outcomes; 
rxrpc_propose_ack_traces;

rxrpc_receive_traces;

rxrpc_recvmsg_traces;

rxrpc_req_ack_traces;

rxrpc_rtt_rx_traces;

rxrpc_rtt_tx_traces;

rxrpc_skb_traces;
@@ -1395,6 +1407,30 @@ TRACE_EVENT(rxrpc_rx_discard_ack, 
		      __entry->call_ackr_prev)

	    );



TRACE_EVENT(rxrpc_req_ack,

	    TP_PROTO(unsigned int call_debug_id, rxrpc_seq_t seq,

		     enum rxrpc_req_ack_trace why),



	    TP_ARGS(call_debug_id, seq, why),



	    TP_STRUCT__entry(

		    __field(unsigned int,		call_debug_id	)

		    __field(rxrpc_seq_t,		seq		)

		    __field(enum rxrpc_req_ack_trace,	why		)

			     ),



	    TP_fast_assign(

		    __entry->call_debug_id = call_debug_id;

		    __entry->seq = seq;

		    __entry->why = why;

			   ),



	    TP_printk("c=%08x q=%08x REQ-%s",

		      __entry->call_debug_id,

		      __entry->seq,

		      __print_symbolic(__entry->why, rxrpc_req_ack_traces))

	    );



#undef EM

#undef E_

#endif /* _TRACE_RXRPC_H */

net/rxrpc/output.c

+23 −9
Original line number Diff line number Diff line
@@ -350,6 +350,7 @@ int rxrpc_send_abort_packet(struct rxrpc_call *call) 
int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb,

			   bool retrans)

{

	enum rxrpc_req_ack_trace why;

	struct rxrpc_connection *conn = call->conn;

	struct rxrpc_wire_header whdr;

	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
@@ -405,16 +406,29 @@ int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb, 
	 * service call, lest OpenAFS incorrectly send us an ACK with some

	 * soft-ACKs in it and then never follow up with a proper hard ACK.

	 */

	if ((!(sp->hdr.flags & RXRPC_LAST_PACKET) ||

	     rxrpc_to_server(sp)

	     ) &&

	    (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events) ||

	     retrans ||

	     call->cong_mode == RXRPC_CALL_SLOW_START ||

	     (call->peer->rtt_count < 3 && sp->hdr.seq & 1) ||

	     ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000),

			  ktime_get_real())))

	if (whdr.flags & RXRPC_REQUEST_ACK)

		why = rxrpc_reqack_already_on;

	else if ((whdr.flags & RXRPC_LAST_PACKET) && rxrpc_to_client(sp))

		why = rxrpc_reqack_no_srv_last;

	else if (test_and_clear_bit(RXRPC_CALL_EV_ACK_LOST, &call->events))

		why = rxrpc_reqack_ack_lost;

	else if (retrans)

		why = rxrpc_reqack_retrans;

	else if (call->cong_mode == RXRPC_CALL_SLOW_START && call->cong_cwnd <= 2)

		why = rxrpc_reqack_slow_start;

	else if (call->tx_winsize <= 2)

		why = rxrpc_reqack_small_txwin;

	else if (call->peer->rtt_count < 3 && sp->hdr.seq & 1)

		why = rxrpc_reqack_more_rtt;

	else if (ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), ktime_get_real()))

		why = rxrpc_reqack_old_rtt;

	else

		goto dont_set_request_ack;



	trace_rxrpc_req_ack(call->debug_id, sp->hdr.seq, why);

	if (why != rxrpc_reqack_no_srv_last)

		whdr.flags |= RXRPC_REQUEST_ACK;

dont_set_request_ack:



	if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {

		static int lose;