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=-5.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 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 7A59BC433E1 for ; Fri, 21 Aug 2020 09:06:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 56BC420720 for ; Fri, 21 Aug 2020 09:06:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="pB+qRKM2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728072AbgHUJG3 (ORCPT ); Fri, 21 Aug 2020 05:06:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50610 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725965AbgHUJG1 (ORCPT ); Fri, 21 Aug 2020 05:06:27 -0400 Received: from mail-pf1-x442.google.com (mail-pf1-x442.google.com [IPv6:2607:f8b0:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AB1D2C061385; Fri, 21 Aug 2020 02:06:27 -0700 (PDT) Received: by mail-pf1-x442.google.com with SMTP id 17so759768pfw.9; Fri, 21 Aug 2020 02:06:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=ClwOCvNdMbSwIvrMHBCrtpWj2Sg/nFcA0Erlf/v7f9I=; b=pB+qRKM2AHS443Cscmz2VK4Ro/JI40bwhD7Jojrqv8T5gBjlAJHShryWeO428vDXYX ba1w9qmlClKif7NBjCAoRMkKUF93bm5sXS8wJu0QtUkrJbhhyqtFDODTNmN5V0lTklSs vkL39anLkBg7pl9m6hMWkwMXJPnmACSdheQtEfT5fo0M9o6448sE4ajPJqRh8iIz4dAT 0bkU/CNmCn78G43XilreYQG+s0mSsgtzijT58BNhCKzJZneW2IDR/Ci5STpAmsl28R9L m8PgYNKRE+rWrQAeEtOUzTB0N9vmecHgcD47MIePwL2oORMeciG+NGBpQD9OQoMlSXd5 lojA== 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=ClwOCvNdMbSwIvrMHBCrtpWj2Sg/nFcA0Erlf/v7f9I=; b=owMckdZwQpIX9bwI1iSY7ifUDL3LAbqXhv1ydeK3wGijcF9uEmFLeOtu9DtbfdHOlO l2O/A6oTlfvvfYyvPaao1lckPV8KQrDmu54oqzvtEI5vjzcHfKsanlNAtleNvEgkAujn LcTdTg5n5972fwk4WBdZW/Ie5Si03aTCN6Vky5K025DUoj6L87w8Pn8MrC11METMF6XD W7Bhcbllp4KiO4L97v5BuR4E9Uh8l5LB6PQj2E3yQORmkI/MIXQ1M+x02/cWv8bmFeer EjkwhmU6jmUWZfEkrzf8AUQM5XQiw5sfVk/5SFhWvNWuWUPtsdnytRDk93XHs0X2J3iV 8g2A== X-Gm-Message-State: AOAM5332SWu5OBKVPvmnfLTTAErWiTaOhNromtavrI0gxLK+ZdlKxDUh f4bx0zyl7+U5WTqcQ1hGero= X-Google-Smtp-Source: ABdhPJzA8ojiKKI8C6VE102tj7IvFCYcv7NiClYkDnphzjF8/kZShjWd0Ex6CLnTjD6jrVu9Pjy4HA== X-Received: by 2002:a62:6185:: with SMTP id v127mr1627684pfb.259.1598000787273; Fri, 21 Aug 2020 02:06:27 -0700 (PDT) Received: from localhost ([124.156.176.71]) by smtp.gmail.com with ESMTPSA id o19sm1388158pjs.8.2020.08.21.02.06.24 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Fri, 21 Aug 2020 02:06:26 -0700 (PDT) Date: Fri, 21 Aug 2020 17:06:27 +0800 From: Yue Hu To: David Laight Cc: "rui.zhang@intel.com" , "daniel.lezcano@linaro.org" , "amit.kucheria@verdurent.com" , "viresh.kumar@linaro.org" , "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "huyue2@yulong.com" , "zhangwen@yulong.com" Subject: Re: [PATCH] thermal: sysfs: Fall back to vmalloc() for cooling device's statistics Message-ID: <20200821170627.00003d5e.zbestahu@gmail.com> In-Reply-To: <7a0c2e488e024c0694fd730f95ba98fb@AcuMS.aculab.com> References: <20200821024406.10404-1-zbestahu@gmail.com> <7a0c2e488e024c0694fd730f95ba98fb@AcuMS.aculab.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; i686-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 21 Aug 2020 08:39:45 +0000 David Laight wrote: > From: Yue Hu > > Sent: 21 August 2020 03:44 > > > > From: Yue Hu > > > > We observed warning about kzalloc() when register thermal cooling device > > in backlight_device_register(). backlight display can be a cooling device > > since reducing screen brightness will can help reduce temperature. > > > > However, ->get_max_state of backlight will assign max brightness of 1024 > > to states. The memory size can be getting 1MB+ due to states * states. > > That is so large to trigger kmalloc() warning. > > I can't help feeling that there is an 'adequate' implementation > that doesn't require anywhere near 1MB of memory. However, it should be a potential issue due to what i described above, rt? Thx. > > David > > - > Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK > Registration No: 1397386 (Wales) >