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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A9A4AC43381 for ; Thu, 21 Mar 2019 22:52:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 74CB721916 for ; Thu, 21 Mar 2019 22:52:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="R8y3VIR2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727359AbfCUWw3 (ORCPT ); Thu, 21 Mar 2019 18:52:29 -0400 Received: from mail-wr1-f68.google.com ([209.85.221.68]:42198 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727257AbfCUWw1 (ORCPT ); Thu, 21 Mar 2019 18:52:27 -0400 Received: by mail-wr1-f68.google.com with SMTP id g3so311849wrx.9 for ; Thu, 21 Mar 2019 15:52:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=SvBV/oli74ysR+5sVv7g6STybbJpJQXquBKi4HPkN7w=; b=R8y3VIR2yu8+nYnqoj6Tad0F7DsNNWwsJ9n/jZPteo79YLixxQblaKiiEAoSwDv0fz SS7sh5ppHFEc6tOx3gIxfHX+h3aUwkJv+7dP6QeGUVakxCag/dtt1oRPUtbRa6QPWxM2 nEXLHQJZmNtfapq/Nv5R2l1GZSH3hu3LZw0pIvnF1Y9fEXuNTMByu+u+MZ04mQU3PJK2 q5136laEalK6RFPDjafs2aQUHIAexAeGi8yaHdfn9jEa36gnbmybXyYPSq+SQDPh8KzS 1AdtTxpxNPhZAAXVAJ4RbP3+O2VosCmD8WdZXad/G6+FXqsJYGtu5j5gYnf3eXqw1fPc 8G4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=SvBV/oli74ysR+5sVv7g6STybbJpJQXquBKi4HPkN7w=; b=PVABHR+/4Cmp/ZyWbeiZOimhg9NV2yv9giGCYtTtS5JD8rDErmBIIkz3QcmUDWcGZv vG4xYqjBHdonCOMuSXaOdR67n5yEFcrcUJIw3kq/KN6sx8n+Cg2xtr7zBqSGG1ijFsMO lvIGh/AkJOKOsKNj3/pIwOOYEsXAAq41h2TLv2tpqZ38cUBt74l3VRb3JMyzuzq53YzB Mg1ZUgZE/OBHTiSsterqAPPUXy42Ia4WXk0AGG5YPdmIJ6QiCpSJAJvGMLsbXufY0H8A qWIkmO7z08kbPhe93v10lGiMYjeAxNIpjv67jwbMHTzWeGQsovkJnQM3P4NXnA/zSG6S pC5Q== X-Gm-Message-State: APjAAAUTQ7ToX9ZGEgdm1vY1GRmbAEZE00QesofQmc+Ci2NQQBnaiZfe JmfHf2nGtnpenp8Z/IbGnc4= X-Google-Smtp-Source: APXvYqzsmCIMcK89CbpKxXDke+6utjIK0m/qH7RjX7xyyWr8sNwiD/YBkcoqJSEHghMPzAK4hluyjw== X-Received: by 2002:adf:ea88:: with SMTP id s8mr4186490wrm.300.1553208745607; Thu, 21 Mar 2019 15:52:25 -0700 (PDT) Received: from [172.31.96.190] ([195.39.71.253]) by smtp.gmail.com with ESMTPSA id g8sm15233104wro.77.2019.03.21.15.52.24 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 21 Mar 2019 15:52:24 -0700 (PDT) Subject: Re: [PATCH net-next 3/3] tcp: add one skb cache for rx To: Eric Dumazet , "David S . Miller" Cc: netdev , Soheil Hassas Yeganeh , Willem de Bruijn , Florian Westphal , Tom Herbert References: <20190321221750.176658-1-edumazet@google.com> <20190321221750.176658-4-edumazet@google.com> From: Eric Dumazet Message-ID: Date: Thu, 21 Mar 2019 15:52:23 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20190321221750.176658-4-edumazet@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 03/21/2019 03:17 PM, Eric Dumazet wrote: > Often times, recvmsg() system calls and BH handling for a particular > TCP socket are done on different cpus. ... > Note that if rps/rfs is used, we do not enable this feature, because > there is high chance that the same cpu is handling both the recvmsg() > system call and the TCP rx path, but that another cpu did the skb > allocations in the device driver right before the RPS/RFS logic. > > To properly handle this case, it seems we would need to record > on which cpu skb was allocated, and use a different channel > to give skbs back to this cpu. Oops a rebase went wrong and I missed the following bit, this will be added in v2. diff --git a/include/net/sock.h b/include/net/sock.h index a7e936ce5a5ac935d90c47f6dd68bf9e8e47ba10..0840f4b27b91eddb205ff42c03f787e5914f755d 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -2439,7 +2439,7 @@ static inline void skb_setup_tx_timestamp(struct sk_buff *skb, __u16 tsflags) static inline void sk_eat_skb(struct sock *sk, struct sk_buff *skb) { __skb_unlink(skb, &sk->sk_receive_queue); - if (!sk->sk_rx_skb_cache) { + if (!static_branch_unlikely(&rps_needed) && !sk->sk_rx_skb_cache) { sk->sk_rx_skb_cache = skb; skb_orphan(skb); return;