Commit 530403d9 authored by David Howells's avatar David Howells
Browse files

rxrpc: Clean up ACK handling 



Clean up the rxrpc_propose_ACK() function.  If deferred PING ACK proposal
is split out, it's only really needed for deferred DELAY ACKs.  All other
ACKs, bar terminal IDLE ACK are sent immediately.  The deferred IDLE ACK
submission can be handled by conversion of a DELAY ACK into an IDLE ACK if
there's nothing to be SACK'd.

Also, because there's a delay between an ACK being generated and being
transmitted, it's possible that other ACKs of the same type will be
generated during that interval.  Apart from the ACK time and the serial
number responded to, most of the ACK body, including window and SACK
parameters, are not filled out till the point of transmission - so we can
avoid generating a new ACK if there's one pending that will cover the SACK
data we need to convey.

Therefore, don't propose a new DELAY or IDLE ACK for a call if there's one
already pending.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
parent 72f0c6fb

include/trace/events/rxrpc.h

+36 −16
Original line number Diff line number Diff line
@@ -158,6 +158,7 @@ 
#define rxrpc_propose_ack_traces \

	EM(rxrpc_propose_ack_client_tx_end,	"ClTxEnd") \

	EM(rxrpc_propose_ack_input_data,	"DataIn ") \

	EM(rxrpc_propose_ack_input_data_hole,	"DataInH") \

	EM(rxrpc_propose_ack_ping_for_check_life, "ChkLife") \

	EM(rxrpc_propose_ack_ping_for_keepalive, "KeepAlv") \

	EM(rxrpc_propose_ack_ping_for_lost_ack,	"LostAck") \
@@ -170,11 +171,6 @@ 
	EM(rxrpc_propose_ack_rotate_rx,		"RxAck  ") \

	E_(rxrpc_propose_ack_terminal_ack,	"ClTerm ")



#define rxrpc_propose_ack_outcomes \

	EM(rxrpc_propose_ack_subsume,		" Subsume") \

	EM(rxrpc_propose_ack_update,		" Update") \

	E_(rxrpc_propose_ack_use,		" New")



#define rxrpc_congest_modes \

	EM(RXRPC_CALL_CONGEST_AVOIDANCE,	"CongAvoid") \

	EM(RXRPC_CALL_FAST_RETRANSMIT,		"FastReTx ") \
@@ -313,7 +309,6 @@ rxrpc_congest_changes; 
rxrpc_congest_modes;

rxrpc_conn_traces;

rxrpc_local_traces;

rxrpc_propose_ack_outcomes;

rxrpc_propose_ack_traces;

rxrpc_receive_traces;

rxrpc_recvmsg_traces;
@@ -1012,7 +1007,7 @@ TRACE_EVENT(rxrpc_timer, 
		    __entry->call		= call->debug_id;

		    __entry->why		= why;

		    __entry->now		= now;

		    __entry->ack_at		= call->ack_at;

		    __entry->ack_at		= call->delay_ack_at;

		    __entry->ack_lost_at	= call->ack_lost_at;

		    __entry->resend_at		= call->resend_at;

		    __entry->expect_rx_by	= call->expect_rx_by;
@@ -1054,7 +1049,7 @@ TRACE_EVENT(rxrpc_timer_expired, 
	    TP_fast_assign(

		    __entry->call		= call->debug_id;

		    __entry->now		= now;

		    __entry->ack_at		= call->ack_at;

		    __entry->ack_at		= call->delay_ack_at;

		    __entry->ack_lost_at	= call->ack_lost_at;

		    __entry->resend_at		= call->resend_at;

		    __entry->expect_rx_by	= call->expect_rx_by;
@@ -1098,17 +1093,15 @@ TRACE_EVENT(rxrpc_rx_lose, 


TRACE_EVENT(rxrpc_propose_ack,

	    TP_PROTO(struct rxrpc_call *call, enum rxrpc_propose_ack_trace why,

		     u8 ack_reason, rxrpc_serial_t serial,

		     enum rxrpc_propose_ack_outcome outcome),

		     u8 ack_reason, rxrpc_serial_t serial),



	    TP_ARGS(call, why, ack_reason, serial, outcome),

	    TP_ARGS(call, why, ack_reason, serial),



	    TP_STRUCT__entry(

		    __field(unsigned int,			call		)

		    __field(enum rxrpc_propose_ack_trace,	why		)

		    __field(rxrpc_serial_t,			serial		)

		    __field(u8,					ack_reason	)

		    __field(enum rxrpc_propose_ack_outcome,	outcome		)

			     ),



	    TP_fast_assign(
@@ -1116,15 +1109,13 @@ TRACE_EVENT(rxrpc_propose_ack, 
		    __entry->why	= why;

		    __entry->serial	= serial;

		    __entry->ack_reason	= ack_reason;

		    __entry->outcome	= outcome;

			   ),



	    TP_printk("c=%08x %s %s r=%08x%s",

	    TP_printk("c=%08x %s %s r=%08x",

		      __entry->call,

		      __print_symbolic(__entry->why, rxrpc_propose_ack_traces),

		      __print_symbolic(__entry->ack_reason, rxrpc_ack_names),

		      __entry->serial,

		      __print_symbolic(__entry->outcome, rxrpc_propose_ack_outcomes))

		      __entry->serial)

	    );



TRACE_EVENT(rxrpc_send_ack,
@@ -1154,6 +1145,35 @@ TRACE_EVENT(rxrpc_send_ack, 
		      __entry->serial)

	    );



TRACE_EVENT(rxrpc_drop_ack,

	    TP_PROTO(struct rxrpc_call *call, enum rxrpc_propose_ack_trace why,

		     u8 ack_reason, rxrpc_serial_t serial, bool nobuf),



	    TP_ARGS(call, why, ack_reason, serial, nobuf),



	    TP_STRUCT__entry(

		    __field(unsigned int,			call		)

		    __field(enum rxrpc_propose_ack_trace,	why		)

		    __field(rxrpc_serial_t,			serial		)

		    __field(u8,					ack_reason	)

		    __field(bool,				nobuf		)

			     ),



	    TP_fast_assign(

		    __entry->call	= call->debug_id;

		    __entry->why	= why;

		    __entry->serial	= serial;

		    __entry->ack_reason	= ack_reason;

		    __entry->nobuf	= nobuf;

			   ),



	    TP_printk("c=%08x %s %s r=%08x nbf=%u",

		      __entry->call,

		      __print_symbolic(__entry->why, rxrpc_propose_ack_traces),

		      __print_symbolic(__entry->ack_reason, rxrpc_ack_names),

		      __entry->serial, __entry->nobuf)

	    );



TRACE_EVENT(rxrpc_retransmit,

	    TP_PROTO(struct rxrpc_call *call, rxrpc_seq_t seq, u8 annotation,

		     s64 expiry),

net/rxrpc/ar-internal.h

+5 −5
Original line number Diff line number Diff line
@@ -516,6 +516,8 @@ enum rxrpc_call_flag { 
	RXRPC_CALL_DISCONNECTED,	/* The call has been disconnected */

	RXRPC_CALL_KERNEL,		/* The call was made by the kernel */

	RXRPC_CALL_UPGRADE,		/* Service upgrade was requested for the call */

	RXRPC_CALL_DELAY_ACK_PENDING,	/* DELAY ACK generation is pending */

	RXRPC_CALL_IDLE_ACK_PENDING,	/* IDLE ACK generation is pending */

};



/*
@@ -582,7 +584,7 @@ struct rxrpc_call { 
	struct rxrpc_net	*rxnet;		/* Network namespace to which call belongs */

	const struct rxrpc_security *security;	/* applied security module */

	struct mutex		user_mutex;	/* User access mutex */

	unsigned long		ack_at;		/* When deferred ACK needs to happen */

	unsigned long		delay_ack_at;	/* When DELAY ACK needs to happen */

	unsigned long		ack_lost_at;	/* When ACK is figured as lost */

	unsigned long		resend_at;	/* When next resend needs to happen */

	unsigned long		ping_at;	/* When next to send a ping */
@@ -834,7 +836,8 @@ int rxrpc_user_charge_accept(struct rxrpc_sock *, unsigned long); 
void rxrpc_propose_ping(struct rxrpc_call *call, u32 serial,

			enum rxrpc_propose_ack_trace why);

void rxrpc_send_ACK(struct rxrpc_call *, u8, rxrpc_serial_t, enum rxrpc_propose_ack_trace);

void rxrpc_propose_ACK(struct rxrpc_call *, u8, u32, enum rxrpc_propose_ack_trace);

void rxrpc_propose_delay_ACK(struct rxrpc_call *, rxrpc_serial_t,

			     enum rxrpc_propose_ack_trace);

void rxrpc_process_call(struct work_struct *);



void rxrpc_reduce_call_timer(struct rxrpc_call *call,
@@ -1016,15 +1019,12 @@ static inline bool __rxrpc_use_local(struct rxrpc_local *local) 
 * misc.c

 */

extern unsigned int rxrpc_max_backlog __read_mostly;

extern unsigned long rxrpc_requested_ack_delay;

extern unsigned long rxrpc_soft_ack_delay;

extern unsigned long rxrpc_idle_ack_delay;

extern unsigned int rxrpc_rx_window_size;

extern unsigned int rxrpc_rx_mtu;

extern unsigned int rxrpc_rx_jumbo_max;



extern const s8 rxrpc_ack_priority[];



/*

 * net_ns.c

 */

net/rxrpc/call_event.c

+26 −69
Original line number Diff line number Diff line
@@ -29,70 +29,29 @@ void rxrpc_propose_ping(struct rxrpc_call *call, u32 serial, 
	spin_lock_bh(&call->lock);



	if (time_before(ping_at, call->ping_at)) {

		rxrpc_inc_stat(call->rxnet, stat_tx_acks[RXRPC_ACK_PING]);

		WRITE_ONCE(call->ping_at, ping_at);

		rxrpc_reduce_call_timer(call, ping_at, now,

					rxrpc_timer_set_for_ping);

		trace_rxrpc_propose_ack(call, why, RXRPC_ACK_PING, serial,

					rxrpc_propose_ack_use);

		trace_rxrpc_propose_ack(call, why, RXRPC_ACK_PING, serial);

	}



	spin_unlock_bh(&call->lock);

}



/*

 * propose an ACK be sent

 * Propose a DELAY ACK be sent in the future.

 */

static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,

				u32 serial, enum rxrpc_propose_ack_trace why)

static void __rxrpc_propose_delay_ACK(struct rxrpc_call *call,

				      rxrpc_serial_t serial,

				      enum rxrpc_propose_ack_trace why)

{

	enum rxrpc_propose_ack_outcome outcome = rxrpc_propose_ack_use;

	unsigned long expiry = rxrpc_soft_ack_delay;

	unsigned long now = jiffies, ack_at;

	s8 prior = rxrpc_ack_priority[ack_reason];



	rxrpc_inc_stat(call->rxnet, stat_tx_acks[ack_reason]);



	/* Update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial

	 * numbers, but we don't alter the timeout.

	 */

	_debug("prior %u %u vs %u %u",

	       ack_reason, prior,

	       call->ackr_reason, rxrpc_ack_priority[call->ackr_reason]);

	if (ack_reason == call->ackr_reason) {

		if (RXRPC_ACK_UPDATEABLE & (1 << ack_reason)) {

			outcome = rxrpc_propose_ack_update;

			call->ackr_serial = serial;

		}

	} else if (prior > rxrpc_ack_priority[call->ackr_reason]) {

		call->ackr_reason = ack_reason;

	call->ackr_serial = serial;

	} else {

		outcome = rxrpc_propose_ack_subsume;

	}



	switch (ack_reason) {

	case RXRPC_ACK_REQUESTED:

		if (rxrpc_requested_ack_delay < expiry)

			expiry = rxrpc_requested_ack_delay;

		break;



	case RXRPC_ACK_DELAY:

	if (rxrpc_soft_ack_delay < expiry)

		expiry = rxrpc_soft_ack_delay;

		break;



	case RXRPC_ACK_IDLE:

		if (rxrpc_idle_ack_delay < expiry)

			expiry = rxrpc_idle_ack_delay;

		break;



	default:

		WARN_ON(1);

		return;

	}





	if (call->peer->srtt_us != 0)

		ack_at = usecs_to_jiffies(call->peer->srtt_us >> 3);

	else
@@ -100,23 +59,23 @@ static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason, 


	ack_at += READ_ONCE(call->tx_backoff);

	ack_at += now;

	if (time_before(ack_at, call->ack_at)) {

		WRITE_ONCE(call->ack_at, ack_at);

	if (time_before(ack_at, call->delay_ack_at)) {

		WRITE_ONCE(call->delay_ack_at, ack_at);

		rxrpc_reduce_call_timer(call, ack_at, now,

					rxrpc_timer_set_for_ack);

	}



	trace_rxrpc_propose_ack(call, why, ack_reason, serial, outcome);

	trace_rxrpc_propose_ack(call, why, RXRPC_ACK_DELAY, serial);

}



/*

 * propose an ACK be sent, locking the call structure

 * Propose a DELAY ACK be sent, locking the call structure

 */

void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason, u32 serial,

void rxrpc_propose_delay_ACK(struct rxrpc_call *call, rxrpc_serial_t  serial,

			     enum rxrpc_propose_ack_trace why)

{

	spin_lock_bh(&call->lock);

	__rxrpc_propose_ACK(call, ack_reason, serial, why);

	__rxrpc_propose_delay_ACK(call, serial, why);

	spin_unlock_bh(&call->lock);

}
@@ -131,6 +90,11 @@ void rxrpc_send_ACK(struct rxrpc_call *call, u8 ack_reason, 


	if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags))

		return;

	if (ack_reason == RXRPC_ACK_DELAY &&

	    test_and_set_bit(RXRPC_CALL_DELAY_ACK_PENDING, &call->flags)) {

		trace_rxrpc_drop_ack(call, why, ack_reason, serial, false);

		return;

	}



	rxrpc_inc_stat(call->rxnet, stat_tx_acks[ack_reason]);
@@ -319,7 +283,6 @@ void rxrpc_process_call(struct work_struct *work) 
	unsigned long now, next, t;

	unsigned int iterations = 0;

	rxrpc_serial_t ackr_serial;

	u8 ackr_reason;



	rxrpc_see_call(call);
@@ -364,18 +327,12 @@ void rxrpc_process_call(struct work_struct *work) 
		set_bit(RXRPC_CALL_EV_EXPIRED, &call->events);

	}



	t = READ_ONCE(call->ack_at);

	t = READ_ONCE(call->delay_ack_at);

	if (time_after_eq(now, t)) {

		trace_rxrpc_timer(call, rxrpc_timer_exp_ack, now);

		cmpxchg(&call->ack_at, t, now + MAX_JIFFY_OFFSET);

		spin_lock_bh(&call->lock);

		ackr_reason = call->ackr_reason;

		ackr_serial = call->ackr_serial;

		call->ackr_reason = 0;

		call->ackr_serial = 0;

		spin_unlock_bh(&call->lock);

		if (ackr_reason)

			rxrpc_send_ACK(call, ackr_reason, ackr_serial,

		cmpxchg(&call->delay_ack_at, t, now + MAX_JIFFY_OFFSET);

		ackr_serial = xchg(&call->ackr_serial, 0);

		rxrpc_send_ACK(call, RXRPC_ACK_DELAY, ackr_serial,

			       rxrpc_propose_ack_ping_for_lost_ack);

	}
@@ -441,7 +398,7 @@ void rxrpc_process_call(struct work_struct *work) 


	set(call->expect_req_by);

	set(call->expect_term_by);

	set(call->ack_at);

	set(call->delay_ack_at);

	set(call->ack_lost_at);

	set(call->resend_at);

	set(call->keepalive_at);

net/rxrpc/call_object.c

+1 −1
Original line number Diff line number Diff line
@@ -222,7 +222,7 @@ static void rxrpc_start_call_timer(struct rxrpc_call *call) 
	unsigned long now = jiffies;

	unsigned long j = now + MAX_JIFFY_OFFSET;



	call->ack_at = j;

	call->delay_ack_at = j;

	call->ack_lost_at = j;

	call->resend_at = j;

	call->ping_at = j;

net/rxrpc/input.c

+4 −4
Original line number Diff line number Diff line
@@ -299,7 +299,7 @@ static bool rxrpc_receiving_reply(struct rxrpc_call *call) 
		now = jiffies;

		timo = now + MAX_JIFFY_OFFSET;

		WRITE_ONCE(call->resend_at, timo);

		WRITE_ONCE(call->ack_at, timo);

		WRITE_ONCE(call->delay_ack_at, timo);

		trace_rxrpc_timer(call, rxrpc_timer_init_for_reply, now);

	}
@@ -542,7 +542,7 @@ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb) 
			/* Send an immediate ACK if we fill in a hole */

			if (!acked) {

				rxrpc_send_ACK(call, RXRPC_ACK_DELAY, serial,

					       rxrpc_propose_ack_input_data);

					       rxrpc_propose_ack_input_data_hole);

				acked = true;

			}

		}
@@ -584,7 +584,7 @@ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb) 
		rxrpc_send_ACK(call, RXRPC_ACK_IDLE, ack_serial,

			       rxrpc_propose_ack_input_data);

	else

		rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, ack_serial,

		rxrpc_propose_delay_ACK(call, ack_serial,

					rxrpc_propose_ack_input_data);



	trace_rxrpc_notify_socket(call->debug_id, serial);