From patchwork Wed Mar 6 00:06:49 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 13583141 X-Patchwork-Delegate: kuba@kernel.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3264A433A1 for ; Wed, 6 Mar 2024 00:07:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709683666; cv=none; b=IMB+8iImI9BM31EXT2LZ7c4AkEvBp4SWVusHCEF5CCEW6u6FVlb2CpFbtQhEOOdl6M0kjq7R8nV5Rp3GQfRq00I1xrSksextSRqPh6LCeDs59KF6tx/61nBIF+9/0k0p5U86MZ7YIm+T6QhaZqp3kCfTfq2hvTWax5ibufkwl48= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709683666; c=relaxed/simple; bh=3W1tGWYV3aFDXvrf37HRbAw1JRDsqeWSwvyhDoPXG2c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RKYjP6qFBYlPUAnzaItAzYAW+RAk0Fa+O7zyfMVIgvr/N+u07XofwAaTLxZDsnaghW4leRzCrY4FpagLhD/9h41sx5H9CIUGMAdg8rzowEFXXkMtWrCBlB3Ik05goMxAx7ruX3Lut9KYuWyydWoXXPcZ7PKXO3wDT/f8LHK8ldQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=LjwbeD3T; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="LjwbeD3T" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1709683663; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Sw1mJ1KMDj2Xrl/dCIVrkP2L8ZbK2rHywBCTVXbbrs8=; b=LjwbeD3TiB46Gj6Ppm+aVtaA5ZYCyLM536OthxdxbS8j15xVo36ahoru3RjdujKi36ipzn IrQL/qg7bp29CTPo7MY70dan95nNdyPtNIc2Dp02puEWC6zcjaifAuREYH5DaqPb30tORs yvU4olkLHMbWVXcE7YuIbGZgJx3w+CM= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-657-busT2Q6wMZ2P9Idl5D9Fuw-1; Tue, 05 Mar 2024 19:07:40 -0500 X-MC-Unique: busT2Q6wMZ2P9Idl5D9Fuw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 82FB88101E0; Wed, 6 Mar 2024 00:07:39 +0000 (UTC) Received: from warthog.procyon.org.com (unknown [10.42.28.114]) by smtp.corp.redhat.com (Postfix) with ESMTP id 39A5D16A9B; Wed, 6 Mar 2024 00:07:38 +0000 (UTC) From: David Howells To: netdev@vger.kernel.org Cc: David Howells , Marc Dionne , Simon Horman , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v3 19/21] rxrpc: Record probes after transmission and reduce number of time-gets Date: Wed, 6 Mar 2024 00:06:49 +0000 Message-ID: <20240306000655.1100294-20-dhowells@redhat.com> In-Reply-To: <20240306000655.1100294-1-dhowells@redhat.com> References: <20240306000655.1100294-1-dhowells@redhat.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.5 X-Patchwork-Delegate: kuba@kernel.org Move the recording of a successfully transmitted DATA or ACK packet that will provide RTT probing to after the transmission. With the I/O thread model, this can be done because parsing of the responding ACK can no longer race with the post-transmission code. Move the various timeout-settings done after successfully transmitting a DATA packet into rxrpc_tstamp_data_packets() and eliminate a number of calls to get the current time. As a consequence we no longer need to cancel a proposed RTT probe on transmission failure. 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 --- net/rxrpc/output.c | 105 +++++++++++++++++---------------------------- 1 file changed, 40 insertions(+), 65 deletions(-) diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c index ec82193e5681..5ea9601efd05 100644 --- a/net/rxrpc/output.c +++ b/net/rxrpc/output.c @@ -63,7 +63,7 @@ static void rxrpc_tx_backoff(struct rxrpc_call *call, int ret) * Receiving a response to the ping will prevent the ->expect_rx_by timer from * expiring. */ -static void rxrpc_set_keepalive(struct rxrpc_call *call) +static void rxrpc_set_keepalive(struct rxrpc_call *call, ktime_t now) { ktime_t delay = ms_to_ktime(READ_ONCE(call->next_rx_timo) / 6); @@ -147,8 +147,8 @@ static void rxrpc_fill_out_ack(struct rxrpc_call *call, /* * Record the beginning of an RTT probe. */ -static int rxrpc_begin_rtt_probe(struct rxrpc_call *call, rxrpc_serial_t serial, - enum rxrpc_rtt_tx_trace why) +static void rxrpc_begin_rtt_probe(struct rxrpc_call *call, rxrpc_serial_t serial, + ktime_t now, enum rxrpc_rtt_tx_trace why) { unsigned long avail = call->rtt_avail; int rtt_slot = 9; @@ -161,30 +161,15 @@ static int rxrpc_begin_rtt_probe(struct rxrpc_call *call, rxrpc_serial_t serial, goto no_slot; call->rtt_serial[rtt_slot] = serial; - call->rtt_sent_at[rtt_slot] = ktime_get_real(); + call->rtt_sent_at[rtt_slot] = now; smp_wmb(); /* Write data before avail bit */ set_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail); trace_rxrpc_rtt_tx(call, why, rtt_slot, serial); - return rtt_slot; + return; no_slot: trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_no_slot, rtt_slot, serial); - return -1; -} - -/* - * Cancel an RTT probe. - */ -static void rxrpc_cancel_rtt_probe(struct rxrpc_call *call, - rxrpc_serial_t serial, int rtt_slot) -{ - if (rtt_slot != -1) { - clear_bit(rtt_slot + RXRPC_CALL_RTT_PEND_SHIFT, &call->rtt_avail); - smp_wmb(); /* Clear pending bit before setting slot */ - set_bit(rtt_slot, &call->rtt_avail); - trace_rxrpc_rtt_tx(call, rxrpc_rtt_tx_cancel, rtt_slot, serial); - } } /* @@ -196,7 +181,8 @@ static void rxrpc_send_ack_packet(struct rxrpc_call *call, struct rxrpc_txbuf *t struct rxrpc_connection *conn; struct rxrpc_ackpacket *ack = (struct rxrpc_ackpacket *)(whdr + 1); struct msghdr msg; - int ret, rtt_slot = -1; + ktime_t now; + int ret; if (test_bit(RXRPC_CALL_DISCONNECTED, &call->flags)) return; @@ -218,9 +204,6 @@ static void rxrpc_send_ack_packet(struct rxrpc_call *call, struct rxrpc_txbuf *t ntohl(ack->serial), ack->reason, ack->nAcks, txb->ack_rwind); - if (ack->reason == RXRPC_ACK_PING) - rtt_slot = rxrpc_begin_rtt_probe(call, txb->serial, rxrpc_rtt_tx_ping); - rxrpc_inc_stat(call->rxnet, stat_tx_ack_send); iov_iter_kvec(&msg.msg_iter, WRITE, txb->kvec, txb->nr_kvec, txb->len); @@ -233,16 +216,14 @@ static void rxrpc_send_ack_packet(struct rxrpc_call *call, struct rxrpc_txbuf *t } else { trace_rxrpc_tx_packet(call->debug_id, whdr, rxrpc_tx_point_call_ack); + now = ktime_get_real(); + if (ack->reason == RXRPC_ACK_PING) + rxrpc_begin_rtt_probe(call, txb->serial, now, rxrpc_rtt_tx_ping); if (txb->flags & RXRPC_REQUEST_ACK) - call->peer->rtt_last_req = ktime_get_real(); + call->peer->rtt_last_req = now; + rxrpc_set_keepalive(call, now); } rxrpc_tx_backoff(call, ret); - - if (!__rxrpc_call_is_complete(call)) { - if (ret < 0) - rxrpc_cancel_rtt_probe(call, txb->serial, rtt_slot); - rxrpc_set_keepalive(call); - } } /* @@ -413,18 +394,36 @@ static size_t rxrpc_prepare_data_packet(struct rxrpc_call *call, struct rxrpc_tx } /* - * Set the times on a packet before transmission + * Set timeouts after transmitting a packet. */ -static int rxrpc_tstamp_data_packets(struct rxrpc_call *call, struct rxrpc_txbuf *txb) +static void rxrpc_tstamp_data_packets(struct rxrpc_call *call, struct rxrpc_txbuf *txb) { - ktime_t tstamp = ktime_get_real(); - int rtt_slot = -1; + ktime_t now = ktime_get_real(); + bool ack_requested = txb->flags & RXRPC_REQUEST_ACK; - txb->last_sent = tstamp; - if (txb->flags & RXRPC_REQUEST_ACK) - rtt_slot = rxrpc_begin_rtt_probe(call, txb->serial, rxrpc_rtt_tx_data); + call->tx_last_sent = now; + txb->last_sent = now; + + if (ack_requested) { + rxrpc_begin_rtt_probe(call, txb->serial, now, rxrpc_rtt_tx_data); + + call->peer->rtt_last_req = now; + if (call->peer->rtt_count > 1) { + ktime_t delay = rxrpc_get_rto_backoff(call->peer, false); - return rtt_slot; + call->ack_lost_at = ktime_add(now, delay); + trace_rxrpc_timer_set(call, delay, rxrpc_timer_trace_lost_ack); + } + } + + if (!test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER, &call->flags)) { + ktime_t delay = ms_to_ktime(READ_ONCE(call->next_rx_timo)); + + call->expect_rx_by = ktime_add(now, delay); + trace_rxrpc_timer_set(call, delay, rxrpc_timer_trace_expect_rx); + } + + rxrpc_set_keepalive(call, now); } /* @@ -437,7 +436,7 @@ static int rxrpc_send_data_packet(struct rxrpc_call *call, struct rxrpc_txbuf *t enum rxrpc_tx_point frag; struct msghdr msg; size_t len; - int ret, rtt_slot = -1; + int ret; _enter("%x,{%d}", txb->seq, txb->len); @@ -479,8 +478,6 @@ static int rxrpc_send_data_packet(struct rxrpc_call *call, struct rxrpc_txbuf *t } retry: - rtt_slot = rxrpc_tstamp_data_packets(call, txb); - /* send the packet by UDP * - returns -EMSGSIZE if UDP would have to fragment the packet * to go out of the interface @@ -493,7 +490,6 @@ static int rxrpc_send_data_packet(struct rxrpc_call *call, struct rxrpc_txbuf *t if (ret < 0) { rxrpc_inc_stat(call->rxnet, stat_tx_data_send_fail); - rxrpc_cancel_rtt_probe(call, txb->serial, rtt_slot); trace_rxrpc_tx_fail(call->debug_id, txb->serial, ret, frag); } else { trace_rxrpc_tx_packet(call->debug_id, whdr, frag); @@ -508,28 +504,7 @@ static int rxrpc_send_data_packet(struct rxrpc_call *call, struct rxrpc_txbuf *t done: if (ret >= 0) { - call->tx_last_sent = txb->last_sent; - if (txb->flags & RXRPC_REQUEST_ACK) { - call->peer->rtt_last_req = txb->last_sent; - if (call->peer->rtt_count > 1) { - ktime_t delay = rxrpc_get_rto_backoff(call->peer, false); - ktime_t now = ktime_get_real(); - - call->ack_lost_at = ktime_add(now, delay); - trace_rxrpc_timer_set(call, delay, rxrpc_timer_trace_lost_ack); - } - } - - if (txb->seq == 1 && - !test_and_set_bit(RXRPC_CALL_BEGAN_RX_TIMER, - &call->flags)) { - ktime_t delay = ms_to_ktime(READ_ONCE(call->next_rx_timo)); - - call->expect_rx_by = ktime_add(ktime_get_real(), delay); - trace_rxrpc_timer_set(call, delay, rxrpc_timer_trace_expect_rx); - } - - rxrpc_set_keepalive(call); + rxrpc_tstamp_data_packets(call, txb); } else { /* Cancel the call if the initial transmission fails, * particularly if that's due to network routing issues that