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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,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 3B0ADC43381 for ; Fri, 22 Mar 2019 13:56:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 08982218D4 for ; Fri, 22 Mar 2019 13:56:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="O3sbiYsc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727780AbfCVN4c (ORCPT ); Fri, 22 Mar 2019 09:56:32 -0400 Received: from mail-wm1-f67.google.com ([209.85.128.67]:54358 "EHLO mail-wm1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727599AbfCVN4b (ORCPT ); Fri, 22 Mar 2019 09:56:31 -0400 Received: by mail-wm1-f67.google.com with SMTP id f3so2268241wmj.4 for ; Fri, 22 Mar 2019 06:56:30 -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=cyNbMga4sMEqi8p+m13Td7bHqaPHFqTymDe6vXforgQ=; b=O3sbiYscMCd53h9bXFYA5gN4Wcnor8PhGq+SnZknfOTnuAECZ/bpQ+xutly8XUsEw9 CHL/lhJXO3NGGwTUhvsAdmSpB+TN20ExYbNcMKgvekn+LSGHTGINmsNrKDCWj+8hzVLC 8nMkUxrXbmdk1H6j98b7JsaD7N32ui/LEQRpkvHtDLIE2kAh+BDKnaObZyGW+Jww+1SN ooG99MT0oHx1uDGfuNtDBgZBsjLKtE9E/3K+IKc9OoIGHIjVBD4W7kp5bhXwMrEANMy6 Vx3g42oRX9ynEGCtyhC/AvIMobLFlnUIfZtal/6unroDerGR6iovpwwx+vHG5MeIDZAX B6Zg== 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=cyNbMga4sMEqi8p+m13Td7bHqaPHFqTymDe6vXforgQ=; b=YsqQ2UxbPk33poIPNhZSnnkpu5KPbkY46gYNIljpMTgYwFmcN8NN1z4PS+OPsMyXIJ 1X0uZk7jFXFTnkvGoNvnr9v5hmDEThuQPdmxhWIaVR0IBCmh5cihXmuzzQR1i4qXd1Ki T8BcMYXGHuRrAJxi8NLMPNZLrRDuZY9XUWaF9cXGFPku8OxOHBROZQEbEpbq9BkreXSW lbniUgLSl6IfTQ/PXGp7fAAcSBYYPebwfuoNPBzGbj/hcXV71rpYuZvfbTT3EYsi8ZTw Ty3WOsWdKEPole042TREz26CKPs+DOuHgXml/cZZugoU7hl310+WbxinexXirOhcb6WW Z34g== X-Gm-Message-State: APjAAAU5/iYvQnM6yqtV0jNQIoCZdcR5FPboYrRs6XXAstwDs4XL2RrB eIaD1GWmmD2qDmIuEU8CApI= X-Google-Smtp-Source: APXvYqw/H1MskyTO4LQexev+Tg/YFrndJOACyaIScjZ2hiwVE5uO+C7BaHnEWByXAcQoMw7bqVO3Sw== X-Received: by 2002:a1c:7e51:: with SMTP id z78mr3225667wmc.82.1553262989583; Fri, 22 Mar 2019 06:56:29 -0700 (PDT) Received: from [172.31.96.190] ([195.39.71.253]) by smtp.gmail.com with ESMTPSA id a130sm11513284wma.14.2019.03.22.06.56.27 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 22 Mar 2019 06:56:28 -0700 (PDT) Subject: Re: [PATCH net-next v2 1/2] net: sched: add empty status flag for NOLOCK qdisc To: Paolo Abeni , netdev@vger.kernel.org Cc: "David S. Miller" , Eric Dumazet , John Fastabend , Ivan Vecera References: <8e2fe320cd3075be079d0bf8c46b98f32935d116.1553188500.git.pabeni@redhat.com> From: Eric Dumazet Message-ID: Date: Fri, 22 Mar 2019 06:56:27 -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: <8e2fe320cd3075be079d0bf8c46b98f32935d116.1553188500.git.pabeni@redhat.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 03/22/2019 01:30 AM, Paolo Abeni wrote: > The queue is marked not empty after acquiring the seqlock, > and it's up to the NOLOCK qdisc clearing such flag on dequeue. > Since the empty status lays on the same cache-line of the > seqlock, it's always hot on cache during the updates. > > > +static inline bool qdisc_is_empty(struct Qdisc *qdisc) const struct Qdisc *qdisc > +{ > + if (qdisc->flags & TCQ_F_NOLOCK) > + return qdisc->empty; > + return !qdisc->q.qlen; > +} > + Other than that : Reivewed-by: Eric Dumazet