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=-0.6 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 B94CCC71122 for ; Sat, 13 Oct 2018 07:30:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7FBEA206B2 for ; Sat, 13 Oct 2018 07:30:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=aol.com header.i=@aol.com header.b="L0G0CFvz" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7FBEA206B2 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=aol.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726799AbeJMPGT (ORCPT ); Sat, 13 Oct 2018 11:06:19 -0400 Received: from sonic304-21.consmr.mail.gq1.yahoo.com ([98.137.68.202]:39293 "EHLO sonic304-21.consmr.mail.gq1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725986AbeJMPGS (ORCPT ); Sat, 13 Oct 2018 11:06:18 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=aol.com; s=a2048; t=1539415814; bh=VeWyWu93oecxnRh1yaB2Ghw9QpXomntceWQVsP/p2Mk=; h=Subject:From:To:Cc:References:Date:In-Reply-To:From:Subject; b=L0G0CFvzyN+aWfs13PnV+zf1Dm4dbnrT0EX7WJ1WbL3EjVY01Y00zUPE0Okb5i0MNVuCKL7ndDyp2UeK58sVCPGxQk7uoxfRYb1s70NW7+N6CvxX7denGaJl1NkUphYuggvQTPXL5po/13e6vMT6gW5tjqBY8ilDGK0yQVLXewY/3eQCta6S5QXbGtiX4pI71LIadWpOZcLo07D6OwF4cNS60EiJZVDud/PQ61WlpW86j+nSRBCxyLfbOYgB9UgQrtEENvOQWWZhafJgrDpH22zeO5gPOQCwLjcDvDVyIs9lwn5nle6v3XsycmvCPWjqhef/RhPxEBFrptTfUlYgOg== X-YMail-OSG: M0QLElkVM1kbjz7a3GgmhSBVy8faaIRGL5tZkH6Pc6xVaQdR4DgWZi91RP3Xj8g gbTM_5dP6.FlNhFneWiPRHlOmKVOT5qylb.HS_6T8.zCRGPCNSRfs8vqp5ZZZLrkhqo1bNd.tqSr pPMGCnCyXLaSusReiys.U3ZSZ142VJPbqCTq9jx4M2avgflQJy7ghXeJnyQYc31tEc2nDsmyptBy NOx0Huw2zO3vvs87BftVLHoLiK8.2Vd4ljoSoefFh6gbdqK26VQotrUR9PZuP3U5fhtrTG8EouqZ k6UG4V4cbT2ATPuq3JmeaiXEZunxenDF5UKQZod0oqVwaujg6HAgDWHx9EmbtCRJ1wxfcNosgaFw Qlc73OF1BA2LZE4tKuz9tIDFB8cJcvOgF0JLF7hxoIsTy5w8MaJcTut62YOgSqncw1ZR_FNPL0px 8eEvmWFyy5uOgMNnKo2V1c7gZ9qPezEGBA9zkMBqHGigAi4wYRrvieSAfnnzy63.cdygTAQos5gu SYp7TlNyd7j35SFpzutsmAEFefsm4KnK9gZiwpHjWZCvLGUz1ViVHqS9RO48fCOly.bDSO5DbucE 1dh.5iMjMGm7Xi30kuzB1xf2EQUkSXxB7H7LGd8wfVj1J7B1uQwTCumWOYNhhupZZkDHWHZtkYRK JzzhpDgizmiLzNmep4Za57A_DZuYz3y..GouxyB6bEncSxxDEXZ1foUYWuSErsQYOFBrcvoR7.Ac xJppRSvWN7.u3O1dIBjXeq1VyLa.30YDPmgUbZN7q0VGClHum8XZNUvTxkNaOImvZ8eQkdzd48jE KK3DWlTCODFr1c32fnbq7kveK11PEOo85X1sTpTeC8RXGacp_asvjbVyPJ5XhjIn65x_.IcZ1k_t bS1TKMS3_iSkbTlODeOTA36MDLKTuUvcKM60wRfgHlZplEevEVLl5zVCwXKLRkMtzIskoMsNDRKK tcinLUZix9vpFrX8WAUT_GYUViWHfKwXpEMbOuJreHn7Y0Oq1v3DadcX3lS1mhBKguj_AVg7Pw_Z TMC_kf5m64hDC4cV0AyVNOI9FcR0Px09m74BzKm8ecZd9aAl5fPhtYLnulMxCeqp60tNC Received: from sonic.gate.mail.ne1.yahoo.com by sonic304.consmr.mail.gq1.yahoo.com with HTTP; Sat, 13 Oct 2018 07:30:14 +0000 Received: from 183.156.49.100 (EHLO [192.168.199.211]) ([183.156.49.100]) by smtp408.mail.gq1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID 5280d62786f15f138cdb59ad97f5b8d5; Sat, 13 Oct 2018 07:30:09 +0000 (UTC) Subject: Re: [RFC PATCH] bit_spinlock: introduce smp_cond_load_relaxed From: Gao Xiang To: Greg Kroah-Hartman Cc: Philippe Ombredanne , Kate Stewart , Thomas Gleixner , linux-kernel@vger.kernel.org, Miao Xie , Chao Yu References: <1539413249-4402-1-git-send-email-hsiangkao@aol.com> <20181013070420.GA29914@kroah.com> <99c4d824-7bd2-a91f-eaaa-8cfe55c66232@aol.com> Message-ID: <71027b95-e1d2-c9fd-06fd-03685acca08a@aol.com> Date: Sat, 13 Oct 2018 15:30:05 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <99c4d824-7bd2-a91f-eaaa-8cfe55c66232@aol.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018/10/13 15:22, Gao Xiang wrote: > For other architectures like x86/arm64, I think they could implement > smp_cond_load_* later. Sorry about that, I mean "amd64". Actually I don't have performance numbers to proof that now. I think it really depends on the detailed architecture hardware implementation. In my opinion, I just think it is better to wrap it up rather than do open-coded all around... do { cpu_relax() } while(...); I was just cleaning up EROFS file system, and saw these piece of code (bit_spinlock) by chance. Therefore I write a patch to get some idea about it.... Thanks, Gao Xiang