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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v2 07/39] rxrpc: Request an ACK on impending Tx stall Date: Wed, 4 Dec 2024 07:46:35 +0000 Message-ID: <20241204074710.990092-8-dhowells@redhat.com> In-Reply-To: <20241204074710.990092-1-dhowells@redhat.com> References: <20241204074710.990092-1-dhowells@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Content-Type: text/plain; charset="utf-8" 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 cc: Marc Dionne cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: linux-afs@lists.infradead.org cc: netdev@vger.kernel.org --- include/trace/events/rxrpc.h | 1 + net/rxrpc/ar-internal.h | 2 +- net/rxrpc/output.c | 7 ++++++- net/rxrpc/proc.c | 5 +++-- 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 @@ =20 #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]; =20 - atomic_t stat_why_req_ack[7]; + atomic_t stat_why_req_ack[8]; =20 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_c= all *call, struct rxrpc_t struct rxrpc_wire_header *whdr =3D txb->kvec[0].iov_base; enum rxrpc_req_ack_trace why; struct rxrpc_connection *conn =3D call->conn; - bool last; + bool last, more; u8 flags; =20 _enter("%x,{%d}", txb->seq, txb->len); @@ -345,6 +345,9 @@ static void rxrpc_prepare_data_subpacket(struct rxrpc_c= all *call, struct rxrpc_t flags =3D txb->flags & RXRPC_TXBUF_WIRE_FLAGS; last =3D txb->flags & RXRPC_LAST_PACKET; =20 + more =3D (!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_c= all *call, struct rxrpc_t why =3D rxrpc_reqack_more_rtt; else if (ktime_before(ktime_add_ms(call->peer->rtt_last_req, 1000), ktime= _get_real())) why =3D rxrpc_reqack_old_rtt; + else if (!last && !more) + why =3D rxrpc_reqack_app_stall; else goto dont_set_request_ack; =20 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=3D%u mrtt=3D%u ortt=3D%u\n", + "Why-Req-A: acklost=3D%u mrtt=3D%u ortt=3D%u stall=3D%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=3D%u retx=3D%u slows=3D%u smtxw=3D%u\n", atomic_read(&rxnet->stat_why_req_ack[rxrpc_reqack_no_srv_last]),