From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5CDFC1DDF8 for ; Fri, 2 Jun 2023 16:31:45 +0000 (UTC) Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F98DB4 for ; Fri, 2 Jun 2023 09:31:43 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-bb1e332f648so2321020276.0 for ; Fri, 02 Jun 2023 09:31:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1685723502; x=1688315502; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=xlqqFN1N3rVCnY6AUfOw9K2CwKWKacY7NYVrRa3An0Q=; b=M3C4Zw/8dlLZJj3k8DVGcQiyDJVoUqSnHarsI6bXP/1+HgJUa4RC7TlRd4MVxtw5Bn nap2kRzpFSPYK5dnkzZxm8TebKC+WPRCWSlWAWaq9cyp+2HAuNVPRVMyZDuObw8PZDbc W2OIIX5xRvby8XpR9M6pmLJ/AMimy3NlyWhUhNhJB+BP3imsy9w6gfhM9EkZnMzqUItb 2gtLbRrC+gQfNVYDhGPCMIZxnxpMJiIxBTw7mK/in328bwebHxHDEtK/IjffUA32xbrC Lk5MJXLEX6LtjNyjOD1pTBhIDHWlLfixJvlPvXlmlDTMcb6BbytZ8c5Mk/3R3ox35kRp TVDw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1685723502; x=1688315502; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=xlqqFN1N3rVCnY6AUfOw9K2CwKWKacY7NYVrRa3An0Q=; b=NwTee0dUFfwb53UJS+4DahPFxESejgVnzoXENqPI/1b0+/vSnipnEIa6w8vnFBATTl A9BxXC4jNNGK3GPBEMaqm6o5Jpe2oY1RCcrBSBGipe1j3aPYIPnPZNSR8XxRJFvGGoKD Ep/ZC6Z6qmEJlWu37hpeJRrL0EZxTuw9Nl15hYnQNBsUf8YmATQZLPtxIfJy4ya/C0HM 1L5rgULG/26YuHyqz67sNGFp/ktNwuEQD9ckVg1ivM5zfY88Le1le5ruN1WEJdCGqi/F jpzLluR2yDlT17pkwv98bNGMFCtO53TAtmp62ZrccynehSXL8i7OSV4DIxer6bTJi1qM 51Ew== X-Gm-Message-State: AC+VfDxXslpJctKiJIXHH6jUwNOm/AtiGtFD4rbW24oBtbv8oOtw3IFH 11gENC42gvF+lBeP6IkezIVBN/+srduYaA== X-Google-Smtp-Source: ACHHUZ5UdESuBbwDDrFsXQbwgpo6NKdHSyFNi32rN8gofPutgtrtwTW0xmV12G5xk9xpyaZW1iytnTyPE9glyg== X-Received: from edumazet1.c.googlers.com ([fda3:e722:ac3:cc00:2b:7d90:c0a8:395a]) (user=edumazet job=sendgmr) by 2002:a05:6902:1545:b0:ba8:181b:2558 with SMTP id r5-20020a056902154500b00ba8181b2558mr2289602ybu.4.1685723502747; Fri, 02 Jun 2023 09:31:42 -0700 (PDT) Date: Fri, 2 Jun 2023 16:31:39 +0000 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.41.0.rc0.172.g3f132b7071-goog Message-ID: <20230602163141.2115187-1-edumazet@google.com> Subject: [PATCH net 0/2] rfs: annotate lockless accesses From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net rfs runs without locks held, so we should annotate read and writes to shared variables. It should prevent compilers forcing writes in the following situation: if (var != val) var = val; A compiler could indeed simply avoid the conditional: var = val; This matters if var is shared between many cpus. Eric Dumazet (2): rfs: annotate lockless accesses to sk->sk_rxhash rfs: annotate lockless accesses to RFS sock flow table include/linux/netdevice.h | 7 +++++-- include/net/sock.h | 18 +++++++++++++----- net/core/dev.c | 6 ++++-- 3 files changed, 22 insertions(+), 9 deletions(-) -- 2.41.0.rc0.172.g3f132b7071-goog