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=-8.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 EBB07C56201 for ; Thu, 12 Nov 2020 14:45:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8C3162224D for ; Thu, 12 Nov 2020 14:45:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728184AbgKLOpw (ORCPT ); Thu, 12 Nov 2020 09:45:52 -0500 Received: from mga09.intel.com ([134.134.136.24]:17665 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727035AbgKLOpv (ORCPT ); Thu, 12 Nov 2020 09:45:51 -0500 IronPort-SDR: lIVe/r462j8jyITzOGIbdcocDAEN6fmmCZul7dE6Ue88swB9F6lqvmUPONDpd+XG/HattSnd8h Q51QWE0iAaqA== X-IronPort-AV: E=McAfee;i="6000,8403,9802"; a="170482625" X-IronPort-AV: E=Sophos;i="5.77,472,1596524400"; d="scan'208";a="170482625" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Nov 2020 06:45:40 -0800 IronPort-SDR: TN6bxwzbqoYGyDaP16dmzETsNXxfLjUrZmlyuA3QZhGcua2QYvLEl45CisQXfDaha2T/zc7k3M +g4KmxpgfJyg== X-IronPort-AV: E=Sophos;i="5.77,472,1596524400"; d="scan'208";a="542280087" Received: from geigerri-mobl.ger.corp.intel.com (HELO btopel-mobl.ger.intel.com) ([10.252.34.175]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Nov 2020 06:45:36 -0800 Subject: Re: [PATCH bpf-next 2/9] net: add SO_BUSY_POLL_BUDGET socket option To: Eric Dumazet , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= Cc: netdev , bpf , magnus.karlsson@intel.com, Alexei Starovoitov , Daniel Borkmann , maciej.fijalkowski@intel.com, "Samudrala, Sridhar" , Jesse Brandeburg , qi.z.zhang@intel.com, Jakub Kicinski , Jonathan Lemon , maximmi@nvidia.com References: <20201112114041.131998-1-bjorn.topel@gmail.com> <20201112114041.131998-3-bjorn.topel@gmail.com> From: =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= Message-ID: <03a5a7d5-e5c9-5c61-8e8e-9393e8772d88@intel.com> Date: Thu, 12 Nov 2020 15:45:35 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.3.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 2020-11-12 15:36, Eric Dumazet wrote: > On Thu, Nov 12, 2020 at 12:41 PM Björn Töpel wrote: >> >> From: Björn Töpel >> >> This option lets a user set a per socket NAPI budget for >> busy-polling. If the options is not set, it will use the default of 8. >> >> Signed-off-by: Björn Töpel >> --- >> > > ... > >> #else /* CONFIG_NET_RX_BUSY_POLL */ >> static inline unsigned long net_busy_loop_on(void) >> @@ -106,7 +108,8 @@ static inline void sk_busy_loop(struct sock *sk, int nonblock) >> >> if (napi_id >= MIN_NAPI_ID) >> napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk, >> - READ_ONCE(sk->sk_prefer_busy_poll)); >> + READ_ONCE(sk->sk_prefer_busy_poll), >> + sk->sk_busy_poll_budget ?: BUSY_POLL_BUDGET); > > Please use : > > READ_ONCE(sk->sk_busy_poll_budget) ?: BUSY_POLL_BUDGET > > Because sk_busy_loop() is usually called without socket lock being held. > > This will prevent yet another KCSAN report. > >> #endif >> } >> > > ... > >> --- a/net/core/sock.c >> +++ b/net/core/sock.c >> @@ -1165,6 +1165,16 @@ int sock_setsockopt(struct socket *sock, int level, int optname, >> else >> sk->sk_prefer_busy_poll = valbool; >> break; >> + case SO_BUSY_POLL_BUDGET: >> + if (val > sk->sk_busy_poll_budget && !capable(CAP_NET_ADMIN)) { >> + ret = -EPERM; >> + } else { >> + if (val < 0) > > if (val < 0 || val > (u16)~0) > >> + ret = -EINVAL; >> + else >> + sk->sk_busy_poll_budget = val; > > > WRITE_ONCE(sk->sk_busy_poll_budget, val); > Thanks for the review! I'll address it all.