Commit 8b5823ea authored by David Howells's avatar David Howells Committed by Jakub Kicinski
Browse files

rxrpc: Request an ACK on impending Tx stall 



Set the REQUEST-ACK flag on the DATA packet we're about to send if we're
about to stall transmission because the app layer isn't keeping up
supplying us with data to transmit.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Link: https://patch.msgid.link/20241204074710.990092-8-dhowells@redhat.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent ff992adb

include/trace/events/rxrpc.h

+1 −0
Original line number Diff line number Diff line
@@ -452,6 +452,7 @@ 


#define rxrpc_req_ack_traces \

	EM(rxrpc_reqack_ack_lost,		"ACK-LOST  ")	\

	EM(rxrpc_reqack_app_stall,		"APP-STALL ")	\

	EM(rxrpc_reqack_more_rtt,		"MORE-RTT  ")	\

	EM(rxrpc_reqack_no_srv_last,		"NO-SRVLAST")	\

	EM(rxrpc_reqack_old_rtt,		"OLD-RTT   ")	\

net/rxrpc/ar-internal.h

+1 −1
Original line number Diff line number Diff line
@@ -110,7 +110,7 @@ struct rxrpc_net { 
	atomic_t		stat_tx_acks[256];

	atomic_t		stat_rx_acks[256];



	atomic_t		stat_why_req_ack[7];

	atomic_t		stat_why_req_ack[8];



	atomic_t		stat_io_loop;

};

net/rxrpc/output.c

+6 −1
Original line number Diff line number Diff line
@@ -330,7 +330,7 @@ static void rxrpc_prepare_data_subpacket(struct rxrpc_call *call, struct rxrpc_t 
	struct rxrpc_wire_header *whdr = txb->kvec[0].iov_base;

	enum rxrpc_req_ack_trace why;

	struct rxrpc_connection *conn = call->conn;

	bool last;

	bool last, more;

	u8 flags;



	_enter("%x,{%d}", txb->seq, txb->len);
@@ -345,6 +345,9 @@ static void rxrpc_prepare_data_subpacket(struct rxrpc_call *call, struct rxrpc_t 
	flags = txb->flags & RXRPC_TXBUF_WIRE_FLAGS;

	last = txb->flags & RXRPC_LAST_PACKET;



	more = (!list_is_last(&txb->call_link, &call->tx_buffer) ||

		!list_empty(&call->tx_sendmsg));



	/* If our RTT cache needs working on, request an ACK.  Also request

	 * ACKs if a DATA packet appears to have been lost.

	 *
@@ -366,6 +369,8 @@ static void rxrpc_prepare_data_subpacket(struct rxrpc_call *call, struct rxrpc_t 
		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 if (!last && !more)

		why = rxrpc_reqack_app_stall;

	else

		goto dont_set_request_ack;

net/rxrpc/proc.c

+3 −2
Original line number Diff line number Diff line
@@ -520,10 +520,11 @@ int rxrpc_stats_show(struct seq_file *seq, void *v) 
		   atomic_read(&rxnet->stat_rx_acks[RXRPC_ACK_IDLE]),

		   atomic_read(&rxnet->stat_rx_acks[0]));

	seq_printf(seq,

		   "Why-Req-A: acklost=%u mrtt=%u ortt=%u\n",

		   "Why-Req-A: acklost=%u mrtt=%u ortt=%u stall=%u\n",

		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_ack_lost]),

		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_more_rtt]),

		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_old_rtt]));

		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_old_rtt]),

		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_app_stall]));

	seq_printf(seq,

		   "Why-Req-A: nolast=%u retx=%u slows=%u smtxw=%u\n",

		   atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_no_srv_last]),