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=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 8A35CC433E0 for ; Mon, 1 Mar 2021 16:14:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 340C464DE5 for ; Mon, 1 Mar 2021 16:14:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237555AbhCAQOU (ORCPT ); Mon, 1 Mar 2021 11:14:20 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:35962 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237513AbhCAQMF (ORCPT ); Mon, 1 Mar 2021 11:12:05 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1614615032; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=I8c36pkCtyN4CLfbJiUbjXLv8s76s8DQupsd9r9qB1M=; b=gXE/PoOznbDaHlvnmHsz+f/yO+30Aqb6+faNzCXgZg4a3WQoYppCIPnQmReBF8mIqAoTut JA13UFW8QFf68tlBKNfmMBTLerL0hcfjZ/l7bK+3QlTCzpxEO2PdfGdY3WR9oZF3QHmdPd IYFBnG0b2O4pUSlexgyeNhtEFVa57Zk= Received: from mail-ej1-f72.google.com (mail-ej1-f72.google.com [209.85.218.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-545-jj-SgU-POaWdHpRywmxSBA-1; Mon, 01 Mar 2021 11:10:31 -0500 X-MC-Unique: jj-SgU-POaWdHpRywmxSBA-1 Received: by mail-ej1-f72.google.com with SMTP id rl7so1527010ejb.16 for ; Mon, 01 Mar 2021 08:10:31 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version:content-transfer-encoding; bh=I8c36pkCtyN4CLfbJiUbjXLv8s76s8DQupsd9r9qB1M=; b=FUuZzE1PAc00mSgveWIN1vJ098SF01igIcyZP329Pm7m8/QKuBTJxDBhF1hDwvvGzN zAmseHhMlUHCw1qeboPTeVrrHblIsvJv3qgvCA0kN49L4HY3qDl1fF7XQIsStgz2XxY9 EpBC5P3/z5wQOqPguYuxHEHytgyl3BIJFQVUnFY/6KExxOQuqQbc0b9Kme5PzUeO/jhY SLLaMHUj68ghoAw2Cyh+v0TMvR5q6IlzhX9pFTv7YA5bm08ojoZMXE7es8BAUgcVjcZs Nw2X+EwqfHilQ6VEGj63+rmYKfexSCV/MHxPDn3VyjifxK9Q+05vSI3Sw0QqUX22HTHt RCnw== X-Gm-Message-State: AOAM530R4DlWWmvwOWwNUABfhmGlqADsLNYrgFfZ7Jkh1NkV1GEongWg ulMjU/tXdGq/3/9+xzx4VJwCsRhFK5lLEVu9UlilFPjBjLH5Qlh2Ciory19wGMyf4Ov6b5OXYlq 9+v0corGutF51 X-Received: by 2002:a17:906:4d18:: with SMTP id r24mr13286021eju.493.1614615030180; Mon, 01 Mar 2021 08:10:30 -0800 (PST) X-Google-Smtp-Source: ABdhPJwg0VI0o+9gqz8X/y2IF8Ux4tSftLQrrJu2j8l6qUsTwkeFP33V3tzX4SUGPpcbw2CJOtYR/A== X-Received: by 2002:a17:906:4d18:: with SMTP id r24mr13285999eju.493.1614615030016; Mon, 01 Mar 2021 08:10:30 -0800 (PST) Received: from alrua-x1.borgediget.toke.dk ([45.145.92.2]) by smtp.gmail.com with ESMTPSA id v11sm15125001eds.14.2021.03.01.08.10.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Mar 2021 08:10:29 -0800 (PST) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 1571C1800F1; Mon, 1 Mar 2021 17:10:29 +0100 (CET) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= , ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org, bpf@vger.kernel.org Cc: =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= , magnus.karlsson@intel.com, jonathan.lemon@gmail.com, maximmi@nvidia.com, andrii@kernel.org Subject: Re: [PATCH bpf-next 2/2] libbpf, xsk: add libbpf_smp_store_release libbpf_smp_load_acquire In-Reply-To: <20210301104318.263262-3-bjorn.topel@gmail.com> References: <20210301104318.263262-1-bjorn.topel@gmail.com> <20210301104318.263262-3-bjorn.topel@gmail.com> X-Clacks-Overhead: GNU Terry Pratchett Date: Mon, 01 Mar 2021 17:10:29 +0100 Message-ID: <87k0qqx3be.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Bj=C3=B6rn T=C3=B6pel writes: > From: Bj=C3=B6rn T=C3=B6pel > > Now that the AF_XDP rings have load-acquire/store-release semantics, > move libbpf to that as well. > > The library-internal libbpf_smp_{load_acquire,store_release} are only > valid for 32-bit words on ARM64. > > Also, remove the barriers that are no longer in use. So what happens if an updated libbpf is paired with an older kernel (or vice versa)? -Toke