From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C00AC433EF for ; Mon, 31 Jan 2022 11:01:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358791AbiAaLBg (ORCPT ); Mon, 31 Jan 2022 06:01:36 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:33094 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358610AbiAaLAZ (ORCPT ); Mon, 31 Jan 2022 06:00:25 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E1AF860BC0; Mon, 31 Jan 2022 11:00:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BDCD6C340E8; Mon, 31 Jan 2022 11:00:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643626824; bh=ZIeqG/4W3iMtANw1XSfN8K18a49BnpXQ6VvJzNGfFAw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ASoVHX3rMzBoYSfztU4k7pyIqAGJCxDf9rb49oXu5TSozp/K/zDing6f7WxbwIGqY kdRhPLoTrXqVefsh+QBsCW63kuS4OugwX90TujRJl931+1uw2F9eV5QBoVtmStzr8X n4jTktc3Ci1M17YFqOuH+dgaoX7biWxWB+n3L1MI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Marc Dionne , David Howells , linux-afs@lists.infradead.org, "David S. Miller" , Sasha Levin Subject: [PATCH 5.4 52/64] rxrpc: Adjust retransmission backoff Date: Mon, 31 Jan 2022 11:56:37 +0100 Message-Id: <20220131105217.437321340@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220131105215.644174521@linuxfoundation.org> References: <20220131105215.644174521@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Howells [ Upstream commit 2c13c05c5ff4b9fc907b07f7311821910ebaaf8a ] Improve retransmission backoff by only backing off when we retransmit data packets rather than when we set the lost ack timer. To this end: (1) In rxrpc_resend(), use rxrpc_get_rto_backoff() when setting the retransmission timer and only tell it that we are retransmitting if we actually have things to retransmit. Note that it's possible for the retransmission algorithm to race with the processing of a received ACK, so we may see no packets needing retransmission. (2) In rxrpc_send_data_packet(), don't bump the backoff when setting the ack_lost_at timer, as it may then get bumped twice. With this, when looking at one particular packet, the retransmission intervals were seen to be 1.5ms, 2ms, 3ms, 5ms, 9ms, 17ms, 33ms, 71ms, 136ms, 264ms, 544ms, 1.088s, 2.1s, 4.2s and 8.3s. Fixes: c410bf01933e ("rxrpc: Fix the excessive initial retransmission timeout") Suggested-by: Marc Dionne Signed-off-by: David Howells Reviewed-by: Marc Dionne Tested-by: Marc Dionne cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/164138117069.2023386.17446904856843997127.stgit@warthog.procyon.org.uk/ Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/rxrpc/call_event.c | 8 +++----- net/rxrpc/output.c | 2 +- 2 files changed, 4 insertions(+), 6 deletions(-) diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c index 9ff85ee8337cd..80e15310f1b29 100644 --- a/net/rxrpc/call_event.c +++ b/net/rxrpc/call_event.c @@ -157,7 +157,7 @@ static void rxrpc_congestion_timeout(struct rxrpc_call *call) static void rxrpc_resend(struct rxrpc_call *call, unsigned long now_j) { struct sk_buff *skb; - unsigned long resend_at, rto_j; + unsigned long resend_at; rxrpc_seq_t cursor, seq, top; ktime_t now, max_age, oldest, ack_ts; int ix; @@ -165,10 +165,8 @@ static void rxrpc_resend(struct rxrpc_call *call, unsigned long now_j) _enter("{%d,%d}", call->tx_hard_ack, call->tx_top); - rto_j = call->peer->rto_j; - now = ktime_get_real(); - max_age = ktime_sub(now, jiffies_to_usecs(rto_j)); + max_age = ktime_sub(now, jiffies_to_usecs(call->peer->rto_j)); spin_lock_bh(&call->lock); @@ -213,7 +211,7 @@ static void rxrpc_resend(struct rxrpc_call *call, unsigned long now_j) } resend_at = nsecs_to_jiffies(ktime_to_ns(ktime_sub(now, oldest))); - resend_at += jiffies + rto_j; + resend_at += jiffies + rxrpc_get_rto_backoff(call->peer, retrans); WRITE_ONCE(call->resend_at, resend_at); if (unacked) diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c index f8b632a5c6197..a4a6f8ee07201 100644 --- a/net/rxrpc/output.c +++ b/net/rxrpc/output.c @@ -426,7 +426,7 @@ done: if (call->peer->rtt_count > 1) { unsigned long nowj = jiffies, ack_lost_at; - ack_lost_at = rxrpc_get_rto_backoff(call->peer, retrans); + ack_lost_at = rxrpc_get_rto_backoff(call->peer, false); ack_lost_at += nowj; WRITE_ONCE(call->ack_lost_at, ack_lost_at); rxrpc_reduce_call_timer(call, ack_lost_at, nowj, -- 2.34.1