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: David 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: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
David Howells 2024-12-04 07:46:35 +00:00 committed by Jakub Kicinski
parent ff992adbc4
commit 8b5823ea43
4 changed files with 11 additions and 4 deletions

View File

@ -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 ") \

View File

@ -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;
};

View File

@ -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;

View File

@ -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]),