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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 54BF1C433DF for ; Fri, 21 Aug 2020 08:39:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3A75A207DF for ; Fri, 21 Aug 2020 08:39:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727887AbgHUIjv convert rfc822-to-8bit (ORCPT ); Fri, 21 Aug 2020 04:39:51 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([185.58.86.151]:51504 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727827AbgHUIjv (ORCPT ); Fri, 21 Aug 2020 04:39:51 -0400 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-267-_gpouvAZPXW8jiqY6_gXxA-1; Fri, 21 Aug 2020 09:39:46 +0100 X-MC-Unique: _gpouvAZPXW8jiqY6_gXxA-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Fri, 21 Aug 2020 09:39:45 +0100 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Fri, 21 Aug 2020 09:39:45 +0100 From: David Laight To: 'Yue Hu' , "rui.zhang@intel.com" , "daniel.lezcano@linaro.org" , "amit.kucheria@verdurent.com" , "viresh.kumar@linaro.org" CC: "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 Thread-Topic: [PATCH] thermal: sysfs: Fall back to vmalloc() for cooling device's statistics Thread-Index: AQHWd2T1s2XRZ72P6kCMdg6RVGFevalCPhSw Date: Fri, 21 Aug 2020 08:39:45 +0000 Message-ID: <7a0c2e488e024c0694fd730f95ba98fb@AcuMS.aculab.com> References: <20200821024406.10404-1-zbestahu@gmail.com> In-Reply-To: <20200821024406.10404-1-zbestahu@gmail.com> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0.002 X-Mimecast-Originator: aculab.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org 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. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)