From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753831AbdKXOii (ORCPT ); Fri, 24 Nov 2017 09:38:38 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56606 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753808AbdKXOig (ORCPT ); Fri, 24 Nov 2017 09:38:36 -0500 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH net-next 08/12] rxrpc: Express protocol timeouts in terms of RTT From: David Howells To: netdev@vger.kernel.org Cc: dhowells@redhat.com, linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org Date: Fri, 24 Nov 2017 14:38:34 +0000 Message-ID: <151153431476.27205.85643049306636998.stgit@warthog.procyon.org.uk> In-Reply-To: <151153425958.27205.13734959199482172941.stgit@warthog.procyon.org.uk> References: <151153425958.27205.13734959199482172941.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Fri, 24 Nov 2017 14:38:36 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Express protocol timeouts for data retransmission and deferred ack generation in terms on RTT rather than specified timeouts once we have sufficient RTT samples. For the moment, this requires just one RTT sample to be able to use this for ack deferral and two for data retransmission. The data retransmission timeout is set at RTT*1.5 and the ACK deferral timeout is set at RTT. Note that the calculated timeout is limited to a minimum of 4ns to make sure it doesn't happen too quickly. Signed-off-by: David Howells --- net/rxrpc/call_event.c | 22 ++++++++++++++++++---- net/rxrpc/sendmsg.c | 7 +++++++ 2 files changed, 25 insertions(+), 4 deletions(-) diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c index c14395d5ad8c..da91f16ac77c 100644 --- a/net/rxrpc/call_event.c +++ b/net/rxrpc/call_event.c @@ -52,7 +52,7 @@ static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason, enum rxrpc_propose_ack_trace why) { enum rxrpc_propose_ack_outcome outcome = rxrpc_propose_ack_use; - unsigned long now, ack_at, expiry = rxrpc_soft_ack_delay; + unsigned long expiry = rxrpc_soft_ack_delay; s8 prior = rxrpc_ack_priority[ack_reason]; /* Pings are handled specially because we don't want to accidentally @@ -116,7 +116,13 @@ static void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason, background) rxrpc_queue_call(call); } else { - now = jiffies; + unsigned long now = jiffies, ack_at; + + if (call->peer->rtt_usage > 0) + ack_at = nsecs_to_jiffies(call->peer->rtt); + else + ack_at = expiry; + ack_at = jiffies + expiry; if (time_before(ack_at, call->ack_at)) { WRITE_ONCE(call->ack_at, ack_at); @@ -160,14 +166,22 @@ static void rxrpc_resend(struct rxrpc_call *call, unsigned long now_j) struct sk_buff *skb; unsigned long resend_at; rxrpc_seq_t cursor, seq, top; - ktime_t now, max_age, oldest, ack_ts; + ktime_t now, max_age, oldest, ack_ts, timeout, min_timeo; int ix; u8 annotation, anno_type, retrans = 0, unacked = 0; _enter("{%d,%d}", call->tx_hard_ack, call->tx_top); + if (call->peer->rtt_usage > 1) + timeout = ns_to_ktime(call->peer->rtt * 3 / 2); + else + timeout = ms_to_ktime(rxrpc_resend_timeout); + min_timeo = ns_to_ktime((1000000000 / HZ) * 4); + if (ktime_before(timeout, min_timeo)) + timeout = min_timeo; + now = ktime_get_real(); - max_age = ktime_sub_ms(now, rxrpc_resend_timeout * 1000 / HZ); + max_age = ktime_sub(now, timeout); spin_lock_bh(&call->lock); diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c index 03e0676db28c..c56ee54fdd1f 100644 --- a/net/rxrpc/sendmsg.c +++ b/net/rxrpc/sendmsg.c @@ -226,6 +226,13 @@ static void rxrpc_queue_packet(struct rxrpc_sock *rx, struct rxrpc_call *call, } else { unsigned long now = jiffies, resend_at; + if (call->peer->rtt_usage > 1) + resend_at = nsecs_to_jiffies(call->peer->rtt * 3 / 2); + else + resend_at = rxrpc_resend_timeout; + if (resend_at < 1) + resend_at = 1; + resend_at = now + rxrpc_resend_timeout; WRITE_ONCE(call->resend_at, resend_at); rxrpc_reduce_call_timer(call, resend_at, now,