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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9FDADC433F5 for ; Thu, 14 Apr 2022 19:20:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345786AbiDNTWn (ORCPT ); Thu, 14 Apr 2022 15:22:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52828 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345266AbiDNTWU (ORCPT ); Thu, 14 Apr 2022 15:22:20 -0400 Received: from mail-qv1-xf36.google.com (mail-qv1-xf36.google.com [IPv6:2607:f8b0:4864:20::f36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 958B8B644D for ; Thu, 14 Apr 2022 12:19:50 -0700 (PDT) Received: by mail-qv1-xf36.google.com with SMTP id a5so4834801qvx.1 for ; Thu, 14 Apr 2022 12:19:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=AmOv5rtWsBjN+AH3Yiwh3/xuZYgmQM8D4+J7GjX0x60=; b=HopD3qrAEWycdOfimAP39aurNTsYZT/k4CNX23xV4pYQRBDzfqGfZmdo/hskHJEDDq eyI7fHLthCq8riD92+r3ERUkkLegaIc7DSazq9AJIS8DoBLzFSQgQzsCppKaIZUwmt+O unHHUfKfCq1xHxSOf03GpNReZrzdcEKaUdHv0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=AmOv5rtWsBjN+AH3Yiwh3/xuZYgmQM8D4+J7GjX0x60=; b=dv35Y1z9ewCuZCibU5MY86Kapu2eIz116r6d4EZrLyfzbJwVRUpyHBbhERn+yVbGWJ XTj0KMb5Q1oq6d9pxfkZxxDK1T2HhbBx+JlmbUXPi05iociacR6JddcdCAy3425xVBuA CvWCX5BaByX+HDy3IV9ZXSxNXdqKlLdmZebSvgjUAqG8sMI9HY2D28Ccba7Sbim7ie6V PqwISLdZ5MaQOVH8D9Bk3FcmgMNwUUPa8jEmfbFDC2j3igixoWi5YxHBiZNaj10HZRw6 WY/iNXui5CsidwHpfvQ/JLXyPAFoA0jvJfi2vYZth1eQoH6EZkSuEYuPYubBkq0sVFhG AkVg== X-Gm-Message-State: AOAM5302i+HmQORMVHVAKg7Yp0mcx4vpcCXLw0Wtb1hnzx83le5TmpNL ARWwhldrURNkWZfTHDjAzO9C2w== X-Google-Smtp-Source: ABdhPJyga0NX+wOgXs9y23L4yB3ht5AzMjEnNjGwPgsAEO1IpewiA3RRQlb9oQk0hYxufs1bdCeEmw== X-Received: by 2002:a05:6214:19c8:b0:444:32f0:2351 with SMTP id j8-20020a05621419c800b0044432f02351mr14188611qvc.109.1649963989216; Thu, 14 Apr 2022 12:19:49 -0700 (PDT) Received: from localhost (228.221.150.34.bc.googleusercontent.com. [34.150.221.228]) by smtp.gmail.com with ESMTPSA id w17-20020a05622a135100b002ef480d2559sm1718617qtk.34.2022.04.14.12.19.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Apr 2022 12:19:48 -0700 (PDT) Date: Thu, 14 Apr 2022 19:19:48 +0000 From: Joel Fernandes To: "Paul E. McKenney" Cc: LKML , Josh Triplett , Lai Jiangshan , Mathieu Desnoyers , rcu , Steven Rostedt , Frederic Weisbecker Subject: Re: [PATCH RFC] rcu/nocb: Provide default all-CPUs mask for RCU_NOCB_CPU=y Message-ID: References: <20220408142232.GA4285@paulmck-ThinkPad-P17-Gen-1> <20220408155002.GF4285@paulmck-ThinkPad-P17-Gen-1> <20220408174908.GK4285@paulmck-ThinkPad-P17-Gen-1> <20220408205440.GL4285@paulmck-ThinkPad-P17-Gen-1> <20220411154109.GX4285@paulmck-ThinkPad-P17-Gen-1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220411154109.GX4285@paulmck-ThinkPad-P17-Gen-1> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 11, 2022 at 08:41:09AM -0700, Paul E. McKenney wrote: [..] > > > [4] All CPUs are offloaded at boot, and any CPU can be de-offloaded > > > and offloaded at runtime. This is the same behavior that > > > you would currently get with CONFIG_RCU_NOCB_CPU_ALL=n and > > > rcu_nocbs=0-N. > > > > Yes, this is the behavior I intend. So then there would not be a need > > to pass a mask (and I suspect for a large number of users, it > > simplifies boot params). > > Very good, and from what I can see, this should work for everyone. Just to clarify, what I am going to do is, if this new option =y, then rcu_nocbs effectively wont do anything. i.e. All CPUs are offloaded at boot. Let me know if we are not on the same page about it though. I do feel that is a sensible choice given =y. If we are on same page, please ignore my comment. > > > I believe that Steve Rostedt's review would carry weight for ChromeOS, > > > however, I am suffering a senior moment on the right person for Android. > > > > I think for Android, Kalesh Singh is in the kernel team and Tim Murray > > is the performance lead. They could appropriately represent their RCU > > needs. > > Sounds good! Please collect a Reviewed-by from one or both of them. Ok. thanks, - Joel