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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 2329CC47247 for ; Fri, 8 May 2020 05:34:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 03D58208CA for ; Fri, 8 May 2020 05:34:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="N73uucdq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726770AbgEHFeE (ORCPT ); Fri, 8 May 2020 01:34:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725875AbgEHFeD (ORCPT ); Fri, 8 May 2020 01:34:03 -0400 Received: from mail-pg1-x544.google.com (mail-pg1-x544.google.com [IPv6:2607:f8b0:4864:20::544]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E297C05BD09 for ; Thu, 7 May 2020 22:34:02 -0700 (PDT) Received: by mail-pg1-x544.google.com with SMTP id l25so356788pgc.5 for ; Thu, 07 May 2020 22:34:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=ek85+5EOYLMSUNDa2pk81mbaX6vTrFpa0o8AoGuV9zA=; b=N73uucdqyUPlc2R76m0kX5oIw8VwOcGlpjiOR17583QDP5OzJzReJ5AM/Z4MXMu44n tf/L2XGF3JhG8xLpjuA46jEKBAcCLTQGTGn6Sst8YZpO37cgPhPGwvpD/KWWDtwJMchT yafjsM1HCnPahw3QPaj0JdouQoLw0+qs2b287bxqogw5fwlUeT16lfoaTqdheM8O2lfC WZZSAqtXNgLBxE9B4Md1wdWZqyrhTNrOy+lK1tGjtTBMrhPkCQEGZiK7VVmt90ay1z8O FYTIHycL6nkKdiolwlm08Ix8FmVc7lrji14z5IAfq84Vo8tD6Z/pyIsKJwfGnt3ObXiz EW1w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=ek85+5EOYLMSUNDa2pk81mbaX6vTrFpa0o8AoGuV9zA=; b=GLQF6sr8gg1lIPAlqucY4/czNKa2bbm8EYz7PtgSFhX/ucH5dylmaflrpDGCDf/b+j 5/zAAMuBKYojIfSJ8TEtXflmXrvVWhWfL2Xd77eYhQj3Gw8+qSQpj7gw0FuQOB6Vzu1w zQgQ+wSiXrZhP0wWxTFMk0sho5bRnTvCBCiqBWH+OosspIzbZK9Cgxv3HNtWX61jpIcc /jm1TkLCzg84sLtYEv/I2jFV3n686vQ/If1jI08L3/+DrRhYcXOO4QLHqE0qrr8Fh9lz 8NEtUe5QueHKAnLbZJsqp2GGiwSa+3Vaf4S4Hnam6gBCY4bDTto973rz6a0Sax6dpTVh c6PQ== X-Gm-Message-State: AGi0PuamPLu2gE8RUbHenLP9WqmgNgGr7XXcfw8QveGd3sMGDrm8p5oD Z69GKbEEBSK4UB1eOdnhtDQGqw== X-Google-Smtp-Source: APiQypLarkLj/uc/Nq9W7V3UCRxdpQ96qkmYq8vA11V45RrVGKvf11uWNMgLc9quK1Zo2sxuDF4DSw== X-Received: by 2002:a63:8e49:: with SMTP id k70mr732060pge.73.1588916041742; Thu, 07 May 2020 22:34:01 -0700 (PDT) Received: from localhost ([122.171.118.46]) by smtp.gmail.com with ESMTPSA id cv21sm1383514pjb.23.2020.05.07.22.34.00 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 07 May 2020 22:34:00 -0700 (PDT) Date: Fri, 8 May 2020 11:03:59 +0530 From: Viresh Kumar To: Quentin Perret Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, sudeep.holla@arm.com, gregkh@linuxfoundation.org, rafael@kernel.org, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, mcgrof@kernel.org, keescook@chromium.org, yzaikin@google.com, fweisbec@gmail.com, tkjos@google.com, kernel-team@android.com Subject: Re: [PATCH 00/14] Modularize schedutil Message-ID: <20200508053359.ul5dbws6vkpdrbef@vireshk-i7> References: <20200507181012.29791-1-qperret@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200507181012.29791-1-qperret@google.com> User-Agent: NeoMutt/20180716-391-311a52 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07-05-20, 19:09, Quentin Perret wrote: > Android is trying very hard to use a single kernel image (commonly > called Generic Kernel Image, or GKI), closely aligned with mainline, to > run on all Android devices regardless of the vendor. > > The GKI project intends to not only improve the status quo for Android > users directly (less fragmentation simplifies updatability), but also > to benefit upstream by forcing all vendors to agree on one common > kernel, that we push hard to be aligned with mainline. > > One challenge to implement GKI is to avoid bloating the kernel by > compiling too many things in, especially given that different devices > need different things. As such, anything that can be turned into a > module helps GKI, by offering an alternative to having that component > built-in. This is true for pretty much anything that can be made > modular, including drivers as well as other kernel components, such as > CPUFreq governors. > > Indeed, in practice, Android devices often ship with only one CPUFreq > governor enabled, and don't require any other that would simply waste > memory for no benefits. All CPUFreq governors can already be built as > modules with one notable exception: schedutil. Though popular in > Android, some devices do not use schedutil, which is why it would be > preferable to not have it unconditionally built in GKI. This series is > an attempt to solve this problem, by making schedutil tristate. > > While modularization is usually not something we want to see near the > scheduler, it appeared to me as I wrote those patches that the > particular case of schedutil was actually not too bad to implement. > We already have to support switching governors at run-time, simply > because userspace is free to do that, so the infrastructure for turning > sugov on and off dynamically is already there. Loading the code a little > later doesn't seem to make that a lot worse. > > Patches 01-05 refactor some code to break the few dependencies on > schedutil being builtin (notably EAS). Patches 06-12 export various > symbols that schedutil needs when compiled as a module. And finally, > patches 13-14 finish off the work by making the Kconfig tristate. IMHO, you have over-broken the patches, like first two could be merged together and all exports could have been done in a single patch, etc. i.e. all related or similar changes together... Acked-by: Viresh Kumar -- viresh