Received: by 2002:a05:6358:45e:b0:b5:b6eb:e1f9 with SMTP id 30csp640189rwe; Wed, 24 Aug 2022 06:54:57 -0700 (PDT) X-Google-Smtp-Source: AA6agR7dlnOJPP8HdQb91RSbVukkvD80iiOm5mh54Mmf1CZY3V6esbXLONE+79bbSVF+urVjv9CZ X-Received: by 2002:a17:90b:1650:b0:1fb:215c:8449 with SMTP id il16-20020a17090b165000b001fb215c8449mr8189153pjb.86.1661349297085; Wed, 24 Aug 2022 06:54:57 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1661349297; cv=none; d=google.com; s=arc-20160816; b=DJ4h/6SmI3a/YaIpPsONwQCdtt1nLD1TdlYhUOn2IRa4gDdlevr2M2HBQlyUNsYHOp kbIZzWo73EEr7wBIWoqFZ1qVL98HA9l4TK19BNmmKsISeH61QBxnY+c2KBxO4y+f8ANi h+aLgap74DVJ+pRuos+gtsMxi4RIrXl+ap4mfXfjNJdiLPKPKrvUn3XlpE3V9O/CNXvF KNCN/n80Q9D3xZfhlO6plADGXYb9zQHOV+N6+tcRO6xjzgXCvGlCfXp5eXU9nWng3B4D tyKQ2dkDwNjHBIllXC3uOi147o+gyjCUg4UbaIdohJLRgQMhGYN+E+6+b7IQfU1bivHx mhng== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:subject:message-id:date:from:references :in-reply-to:mime-version:dkim-signature; bh=ZLtAsF2uZ9ocOb5E6/KIG4KyzKa728jhYH5YX05G5Ac=; b=Ap/LgGBZjS9x7Y4mAQaeG4+dUbZVaXdM58qGLzXZBWSgs/IowSbxd9dv+i5PXEAUL1 8sL1OyR04iW4Q7pf5eCNaGledOaYDEXfnxTKFl8v2dFthkzSJwU/l+3iEVezn2OJOk8j bf66p5zzIOc6JKhWWg6iOB+TzGQuBV2w3vuUoZJsSoFHsOgZRPUdBsUHuysodVogTpQu Th9UFtlQORkR2/gLt88vUDIrztjbD31tkdk6gCJbwIVb/tLKCzsunIhlTdCPitm1BQ4H BixNNcjDo7k0OML59ZEXNsthAfSTxKgKaXm+0OHd90s3ciK3C55zlzOMv8jZa4wSJvC7 330A== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@zx2c4.com header.s=20210105 header.b=iGKKsQGw; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=zx2c4.com Return-Path: Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id z7-20020a170902ccc700b0016caa701d5bsi17742657ple.487.2022.08.24.06.54.45; Wed, 24 Aug 2022 06:54:57 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@zx2c4.com header.s=20210105 header.b=iGKKsQGw; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=zx2c4.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239494AbiHXNvY (ORCPT + 99 others); Wed, 24 Aug 2022 09:51:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48038 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238763AbiHXNty (ORCPT ); Wed, 24 Aug 2022 09:49:54 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3776F9A9DA; Wed, 24 Aug 2022 06:45:09 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A931B61786; Wed, 24 Aug 2022 13:45:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D79A4C433D6; Wed, 24 Aug 2022 13:45:06 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="iGKKsQGw" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1661348703; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ZLtAsF2uZ9ocOb5E6/KIG4KyzKa728jhYH5YX05G5Ac=; b=iGKKsQGwwzxqfQugSyH9e8+0wsfHfn7IASIQBlcjRKKwha/bjUVL0mcdoCXN6zZh51j72s Ci1MTsR0ad1DtVx5X0D1UnePA5xn2WGTWOE53t0kJkLDs0nfVmEyerJtOWplVsej7D809S I4luJft4eIGfz54Wxl4PMBRgQN1m6Hc= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id d95281f0 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Wed, 24 Aug 2022 13:45:03 +0000 (UTC) Received: by mail-yw1-f176.google.com with SMTP id 00721157ae682-3375488624aso431904707b3.3; Wed, 24 Aug 2022 06:45:02 -0700 (PDT) X-Gm-Message-State: ACgBeo3BGl+Ru6yEq67sjmpUY3YFP8hVwuP/HKWWrO4hWKrnHtr4ws1j 2zKZvL4FUC6EQg+CHAH+QfYEJcMGytRfvW0R0Vs= X-Received: by 2002:a81:6141:0:b0:328:30e0:a6ca with SMTP id v62-20020a816141000000b0032830e0a6camr32712430ywb.454.1661348699719; Wed, 24 Aug 2022 06:44:59 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a05:7110:2589:b0:191:2a95:8ff9 with HTTP; Wed, 24 Aug 2022 06:44:59 -0700 (PDT) In-Reply-To: References: <20220822021520.6996-1-kernelfans@gmail.com> <20220822021520.6996-7-kernelfans@gmail.com> From: "Jason A. Donenfeld" Date: Wed, 24 Aug 2022 09:44:59 -0400 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC 06/10] rcu/hotplug: Make rcutree_dead_cpu() parallel To: Pingfan Liu Cc: Joel Fernandes , LKML , rcu , "Paul E. McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Josh Triplett , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Thomas Gleixner , Steven Price , Mark Rutland , Kuppuswamy Sathyanarayanan Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/22/22, Pingfan Liu wrote: > On Mon, Aug 22, 2022 at 02:08:38PM -0400, Joel Fernandes wrote: >> On Sun, Aug 21, 2022 at 10:16 PM Pingfan Liu >> wrote: >> > >> > In order to support parallel, rcu_state.n_online_cpus should be >> > atomic_dec() >> >> What does Parallel mean? Is that some kexec terminology? >> > > 'Parallel' means concurrent. It is not a kexec terminology, instead, > should be SMP. Only sort of. See section A.6 of Paul 's book: http://kernel.org/pub/linux/kernel/people/paulmck/perfbook/perfbook.html Jason