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authorDavid Howells <dhowells@redhat.com>2024-12-04 07:46:35 +0000
committerJakub Kicinski <kuba@kernel.org>2024-12-09 13:48:24 -0800
commit8b5823ea437624b53ecf084b6dd582760f110394 (patch)
tree72bd79b0fb85b519cfff42fa3d0e6b9b99250ac3
parentff992adbc470c86d2dcb66f5ed837fbb3c1a561e (diff)
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>
-rw-r--r--include/trace/events/rxrpc.h1
-rw-r--r--net/rxrpc/ar-internal.h2
-rw-r--r--net/rxrpc/output.c7
-rw-r--r--net/rxrpc/proc.c5
4 files changed, 11 insertions, 4 deletions
diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h
index 62064f63d6eb..d86b5f07d292 100644
--- a/include/trace/events/rxrpc.h
+++ b/include/trace/events/rxrpc.h
@@ -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 ") \
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index fcdfbc1d5aaf..d0fd37bdcfe9 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -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;
};
diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index 50d5f2a02458..b93a5d50be3e 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -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;
diff --git a/net/rxrpc/proc.c b/net/rxrpc/proc.c
index cdf32f0d8e0e..ce4d48bdfbe9 100644
--- a/net/rxrpc/proc.c
+++ b/net/rxrpc/proc.c
@@ -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]),