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Tue, 18 Mar 2025 00:28:02 +0000 Received: from sarah.nbl.nsn-rdnet.net (sarah.nbl.nsn-rdnet.net [10.0.73.150]) by fr711usmtp2.zeu.alcatel-lucent.com (GMO) with ESMTP id 52I0RNBt024935; Tue, 18 Mar 2025 00:28:10 GMT From: chia-yu.chang@nokia-bell-labs.com To: netdev@vger.kernel.org, dave.taht@gmail.com, pabeni@redhat.com, jhs@mojatatu.com, kuba@kernel.org, stephen@networkplumber.org, xiyou.wangcong@gmail.com, jiri@resnulli.us, davem@davemloft.net, edumazet@google.com, horms@kernel.org, andrew+netdev@lunn.ch, donald.hunter@gmail.com, ast@fiberby.net, liuhangbin@gmail.com, shuah@kernel.org, linux-kselftest@vger.kernel.org, ij@kernel.org, ncardwell@google.com, koen.de_schepper@nokia-bell-labs.com, g.white@cablelabs.com, ingemar.s.johansson@ericsson.com, mirja.kuehlewind@ericsson.com, cheshire@apple.com, rs.ietf@gmx.at, Jason_Livingood@comcast.com, vidhi_goel@apple.com Cc: Chia-Yu Chang Subject: [PATCH v2 net-next 13/15] tcp: accecn: try to fit AccECN option with SACK Date: Tue, 18 Mar 2025 01:27:08 +0100 Message-Id: <20250318002710.29483-14-chia-yu.chang@nokia-bell-labs.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250318002710.29483-1-chia-yu.chang@nokia-bell-labs.com> References: <20250318002710.29483-1-chia-yu.chang@nokia-bell-labs.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: AM4PEPF00027A5E:EE_|PA4PR07MB8390:EE_ X-MS-Office365-Filtering-Correlation-Id: 7fc59d8f-a9cc-4966-c753-08dd65b3be6d X-LD-Processed: 5d471751-9675-428d-917b-70f44f9630b0,ExtAddr X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|36860700013|1800799024|376014|7416014|921020; X-Microsoft-Antispam-Message-Info: =?utf-8?q?vDD4sXD5Wu+pn1X2iYmbbDgpI1/rfgg?= =?utf-8?q?QUZz6UuVm5YQ/32P2arIqyoz/wIGemnrgPfag5NXO4Q0ag4gX1IuPH2jm/XuBD8Ii?= =?utf-8?q?FCBHRvKa79Xp6BppIkQHLyVaUiqDQvsoZC55NKyC0kbmSPHB8/t91zuL5noxSBD74?= =?utf-8?q?+/1YuE6I9E1Lpxbd62dKvb9xqr3PykWb195/RN4wCBu295Dn5H37lbb9nAdRv2URa?= =?utf-8?q?OWRMkE7c0hzYIWyeUnmHcCBe8BqhVIypuRFgh6a1/Yu+gw/qXaDBdYVoR6twj68sv?= =?utf-8?q?R1xy9MZWpWY1lyrmnOeOGAq51LXPQbjBU7cBjjhe/NX2Oc5O5JvWLrpW6dubhj+JW?= =?utf-8?q?lPywXIO4S8qShxbCmUBXSdl/YewwGmzUGEbgYS9QLDgEP3IVZJnAzhIz+dgGlINBD?= =?utf-8?q?8sqykgJ5bpBgjmqcLoHHvcGcwtgusg6AKj9a0G0CDsIT0zenB9/HKNrIxwmHwVrgs?= =?utf-8?q?1KmdbJybIWDaEmZFi1QANIHzJBncASZne6CNFkjQqNJywYj9R15If89zlMXERzNes?= =?utf-8?q?cfR9WlVc7vEvxbO3mX7BxfOP9OB0dxk3+rHwDH9nFrfszuJ12eD6dyaENRXdconjh?= =?utf-8?q?lWueKc7wnkQcD0e942x0mOsnt+rsQDlmvLK0C0E5MgaP6p7BBZsVF98E2Z0+cjYQP?= =?utf-8?q?om8BdVJNDx61VG/wxdZBah+gDoqDb6r5/r4IFJ7WdYrIDP39QDdDKTNf3KOZ5giSl?= =?utf-8?q?bb0SuZvk9ghwUUpvv7lz6IcxA0EiIRj9vUoRatoOlhedjo975nrpH/TifbSIY1Bts?= =?utf-8?q?O29ABMFzUj0LjGvuc+njqCba6ZT4x5pBYzR2MDPPggi87lT0rCAhY15f1qlt4iU/z?= =?utf-8?q?FoVY9HlxX09U36NoqKUbQ07pWEbmCSgDBa+RKfoOI1Hxt3D7gE5wGchA3SClJdqMM?= =?utf-8?q?CVRuCu9cN9rU6SBSQ7qGgahfZFWuE2SfXPvRB4eMDEVoE7ppK7+aGFLZy6JRpZVw6?= =?utf-8?q?5npUhcdpfoZzjChcfU6cMpd/s50fCHeWS1LNBkuFF2cu/sxx9lUpABD25Wpr8aJf2?= =?utf-8?q?Z/48/wlmY2yZgyGIeSZuuaEN8xpQBK1zBAFFeKBTkA65JDpxnikalDATBkEWuLmdV?= =?utf-8?q?gIaWGczmmN3LHg83GhMvWXJ4o6ufe9Kqbx7o9SsDANb1fEP84Mp83SIHaMLMi86QY?= =?utf-8?q?QgyXj5WdgT2mvAKkv1e+vAnKMEHmgjrtgP24ABwvuagFPbYjkujCWGi4u+CceGzYU?= =?utf-8?q?IuWPPriFAHnuwYTqqPvuSuvL0bpFMhYdbq8+4Nl6AjiGK+PVPhpbCnuk0rU3LqDzF?= =?utf-8?q?ThsYR6/HH/b3YKOpqdUlru8FUhnAsK1PYb1t0Wm5G/Z7O7aMVtu4W1FxFHtU9oNVq?= =?utf-8?q?6FNAjW1lmwpXLdULdthy/mXNxxr0tKU+0bzYWUTHBuN3cpXEm/t34WqfdmMgpmRIe?= =?utf-8?q?m3AZBm4/hQb0zkf78jbjzOyM++KAtUxhIoY5Z2GibhFfysStMMG4m4=3D?= X-Forefront-Antispam-Report: CIP:131.228.6.100;CTRY:FI;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:fr711usmtp2.zeu.alcatel-lucent.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(82310400026)(36860700013)(1800799024)(376014)(7416014)(921020);DIR:OUT;SFP:1101; X-OriginatorOrg: nokia-bell-labs.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Mar 2025 00:28:02.3957 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 7fc59d8f-a9cc-4966-c753-08dd65b3be6d X-MS-Exchange-CrossTenant-Id: 5d471751-9675-428d-917b-70f44f9630b0 X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=5d471751-9675-428d-917b-70f44f9630b0;Ip=[131.228.6.100];Helo=[fr711usmtp2.zeu.alcatel-lucent.com] X-MS-Exchange-CrossTenant-AuthSource: AM4PEPF00027A5E.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: PA4PR07MB8390 From: Ilpo Järvinen As SACK blocks tend to eat all option space when there are many holes, it is useful to compromise on sending many SACK blocks in every ACK and try to fit AccECN option there by reduction the number of SACK blocks. But never go below two SACK blocks because of AccECN option. As AccECN option is often not put to every ACK, the space hijack is usually only temporary. Signed-off-by: Ilpo Järvinen Signed-off-by: Chia-Yu Chang --- net/ipv4/tcp_output.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 6bee68795b0e..fafca7cd369b 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -981,8 +981,21 @@ static int tcp_options_fit_accecn(struct tcp_out_options *opts, int required, opts->num_accecn_fields--; size -= TCPOLEN_ACCECN_PERFIELD; } - if (opts->num_accecn_fields < required) + if (opts->num_accecn_fields < required) { + if (opts->num_sack_blocks > 2) { + /* Try to fit the option by removing one SACK block */ + opts->num_sack_blocks--; + size = tcp_options_fit_accecn(opts, required, + remaining + + TCPOLEN_SACK_PERBLOCK, + max_combine_saving); + if (opts->options & OPTION_ACCECN) + return size - TCPOLEN_SACK_PERBLOCK; + + opts->num_sack_blocks++; + } return 0; + } opts->options |= OPTION_ACCECN; return size;