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 C161CC32754 for ; Tue, 6 Aug 2019 04:01:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 75702216B7 for ; Tue, 6 Aug 2019 04:01:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="Ur1TTksH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726239AbfHFEBD (ORCPT ); Tue, 6 Aug 2019 00:01:03 -0400 Received: from mail-pf1-f195.google.com ([209.85.210.195]:37755 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725616AbfHFEBC (ORCPT ); Tue, 6 Aug 2019 00:01:02 -0400 Received: by mail-pf1-f195.google.com with SMTP id 19so40725538pfa.4 for ; Mon, 05 Aug 2019 21:01:02 -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=3TFYUjYnPdFwbR/gZPSkhap+wwa2+UTWPedjNUfvaCs=; b=Ur1TTksHqEzo+3mspdwHLh/GPTMgpYFALryUKxCRN74kc9TNhwuseHRUfrQ9+59trc blJCGvuLj4KJ9h4GIfQaAG0/v5p5aZx6ZkjjIhmxB2gGTlbY/Uyv/yNEHl83mkKeUfwl Rjdynz3duonl57UAn+YkaQxrfx6OWvdYv7ied0JgviZXwpaKMlYB50/y7i/UCcUFwt9z /7PMYLpV96bsmqqQMkxc7RQjIAYURoc5Ji5kZcYDIgJffde5ee2BBZHS+v4PUvC2/0Os khZhvBeQ82l4kJJCLTlbg4ilgJXyPADJOwl+qUYiA5uWsAYsE7Ri1R0TRdugbH9aBrl0 C64Q== 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=3TFYUjYnPdFwbR/gZPSkhap+wwa2+UTWPedjNUfvaCs=; b=MGc1LLyL9DxJAQWv2q7FX7QXI5NTiFda/GiUAT/5BuDMl1rn8BCXl9qEGrZNLWonFs x5NClYAoUQwdjYropN3QTI71LARqZABnhvQZw0vbl10XyBlawzvu/kPFrbKe95nm1/qq 6Q8hK1vHi6k9NU1u3PVU+igseQ+JHW7h9qpk18iFac54PDgFnoZ1z0qa49JMx2TsHYN6 t37D4nMc/owqIsPfdfCOVhx/TIEO+o2tVCPRyI1pCv2oDtzwaAYEdV/LpoIHEX+USDmK 0KZsqN7/W6/qtkiFid76ZucDmi0yLpu6Es8rXFDrntgXx2R+NnzH8wWlFLCPDzZX32xW /2GQ== X-Gm-Message-State: APjAAAURpI+icc18lVMAuOvWzR+SKw9FjHH9RVYpmorZsVcKkuSU77um 90h2+W1JrQba5WVemYT7vnV9uw== X-Google-Smtp-Source: APXvYqx1/4OA0fwfHhSRGbm8u/zUMW5hd76Tbpp6hlQ3NVYY8btzNNtrrWg6ZXfxmtcL7Je7iiXrQA== X-Received: by 2002:a62:82c2:: with SMTP id w185mr1548036pfd.202.1565064061906; Mon, 05 Aug 2019 21:01:01 -0700 (PDT) Received: from localhost ([122.172.146.3]) by smtp.gmail.com with ESMTPSA id a15sm118235731pfg.102.2019.08.05.21.01.00 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 05 Aug 2019 21:01:01 -0700 (PDT) Date: Tue, 6 Aug 2019 09:30:59 +0530 From: Viresh Kumar To: "Rafael J. Wysocki" Cc: Doug Smythies , "'Rafael J. Wysocki'" , 'Ingo Molnar' , 'Peter Zijlstra' , 'Linux PM' , 'Vincent Guittot' , 'Joel Fernandes' , "'v4 . 18+'" , 'Linux Kernel Mailing List' Subject: Re: [PATCH] cpufreq: schedutil: Don't skip freq update when limits change Message-ID: <20190806040059.ty4qhjarx4obomhs@vireshk-i7> References: <000001d54892$a25b86b0$e7129410$@net> <20190802034819.vywlces7rxzfy33f@vireshk-i7> <1599417.3YyTWY6lWL@kreacher> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1599417.3YyTWY6lWL@kreacher> 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 02-08-19, 11:11, Rafael J. Wysocki wrote: > On Friday, August 2, 2019 5:48:19 AM CEST Viresh Kumar wrote: > > On 01-08-19, 10:57, Doug Smythies wrote: > > > Disagree. > > > All I did was use a flag where it used to be set to UNIT_MAX, to basically > > > implement the same thing. > > > > And the earlier code wasn't fully correct as well, that's why we tried > > to fix it earlier. > > Your argument seems to be "There was an earlier problem related to this, which > was fixed, so it is fragile and I'd rather avoid it". Still, you are claiming that the > code was in fact incorrect and you are not giving convincing arguments to > support that. > > > So introducing the UINT_MAX thing again would be > > wrong, even if it fixes the problem for you. > > Would it be wrong, because it would reintroduce the fragile code, or would it > be wrong, because it would re-introduce a bug? What bug if so? There will be two issues here if that patch is reintroduced: - It will cause the BUG to reappear, which was fixed by the earlier commit. The commit log of ecd28842912 explains the bug in detail. - And overriding next_freq as a flag will make the code fragile and we may have similar bugs coming up. But yeah, lets continue discussion on the intel-pstate patch now. -- viresh