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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED,USER_AGENT_MUTT 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 84EFBC3279B for ; Fri, 6 Jul 2018 13:22:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 48E2E23FCE for ; Fri, 6 Jul 2018 13:22:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 48E2E23FCE Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=c-sky.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 S933664AbeGFNW2 (ORCPT ); Fri, 6 Jul 2018 09:22:28 -0400 Received: from smtp2200-217.mail.aliyun.com ([121.197.200.217]:43104 "EHLO smtp2200-217.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753616AbeGFNW0 (ORCPT ); Fri, 6 Jul 2018 09:22:26 -0400 X-Alimail-AntiSpam: AC=CONTINUE;BC=0.1106483|-1;CH=green;FP=0|0|0|0|0|-1|-1|-1;HT=e02c03301;MF=ren_guo@c-sky.com;NM=1;PH=DS;RN=13;RT=13;SR=0;TI=SMTPD_---.CN6-5tf_1530883335; Received: from localhost(mailfrom:ren_guo@c-sky.com fp:SMTPD_---.CN6-5tf_1530883335) by smtp.aliyun-inc.com(10.147.41.231); Fri, 06 Jul 2018 21:22:15 +0800 Date: Fri, 6 Jul 2018 21:22:15 +0800 From: Guo Ren To: Peter Zijlstra Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, daniel.lezcano@linaro.org, jason@lakedaemon.net, arnd@arndb.de, c-sky_gcc_upstream@c-sky.com, gnu-csky@mentor.com, thomas.petazzoni@bootlin.com, wbx@uclibc-ng.org, green.hu@gmail.com, Will Deacon Subject: Re: [PATCH V2 16/19] csky: SMP support Message-ID: <20180706132215.GB30265@guoren> References: <21d859826fe19aecaa2aefe3103d6d33e6f1b925.1530465326.git.ren_guo@c-sky.com> <20180705180503.GH2530@hirez.programming.kicks-ass.net> <20180706060740.GB8707@guoren> <20180706093932.GT2476@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180706093932.GT2476@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 06, 2018 at 11:39:32AM +0200, Peter Zijlstra wrote: > On Fri, Jul 06, 2018 at 02:07:40PM +0800, Guo Ren wrote: > > > > Please explain those mb()'s... I'm thinking you meant to use smp_mb(). > > Yes, smp_mb(). Current smp_mb()&mb() is the same: sync.is. > > > > In next version patch, I'll seperate smp_mb() and mb() and use ld/st.barrier > > instead of sync.is. Sync.is is expensive that it flush cpu's pipeline. > > I'll second my own call for documentation, because now there's three > memory ordering instructions: > > "SYNC", "SYNC.IS" and "LD/ST.BARRIER" > > None of which have yet been explained. In C-SKY there are: sync: completion barrier sync.s: completion barrier and shareable to other cores sync.i: completion barrier with flush cpu pipeline sync.is: completion barrier with flush cpu pipeline and shareable to other cores bar.brwarw: ordering barrier for all load/store instructions before it bar.brwarws: ordering barrier for all load/store instructions before it and shareable to other cores bar.brar: ordering barrier for all load instructions before it bar.brars: ordering barrier for all load instructions before it and shareable to other cores bar.bwaw: ordering barrier for all store instructions before it bar.bwaws: ordering barrier for all store instructions before it and shareable to other cores