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=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 21FA1C43603 for ; Fri, 6 Dec 2019 20:07:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EF0E52075C for ; Fri, 6 Dec 2019 20:07:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726377AbfLFUHB (ORCPT ); Fri, 6 Dec 2019 15:07:01 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:60166 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726325AbfLFUHB (ORCPT ); Fri, 6 Dec 2019 15:07:01 -0500 Received: from localhost (unknown [IPv6:2601:601:9f00:1c3::3d5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 6E3551512217D; Fri, 6 Dec 2019 12:07:00 -0800 (PST) Date: Fri, 06 Dec 2019 12:06:59 -0800 (PST) Message-Id: <20191206.120659.1363670425922838677.davem@davemloft.net> To: edumazet@google.com Cc: netdev@vger.kernel.org, eric.dumazet@gmail.com, pabeni@redhat.com, David.Laight@aculab.com Subject: Re: [PATCH net] net: avoid an indirect call in ____sys_recvmsg() From: David Miller In-Reply-To: <20191206173836.34294-1-edumazet@google.com> References: <20191206173836.34294-1-edumazet@google.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Fri, 06 Dec 2019 12:07:00 -0800 (PST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Eric Dumazet Date: Fri, 6 Dec 2019 09:38:36 -0800 > CONFIG_RETPOLINE=y made indirect calls expensive. > > gcc seems to add an indirect call in ____sys_recvmsg(). > > Rewriting the code slightly makes sure to avoid this indirection. > > Alternative would be to not call sock_recvmsg() and instead > use security_socket_recvmsg() and sock_recvmsg_nosec(), > but this is less readable IMO. > > Signed-off-by: Eric Dumazet Applied, thanks Eric.