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=-5.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 9BD23C43381 for ; Fri, 29 Mar 2019 16:27:02 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6C7692173C for ; Fri, 29 Mar 2019 16:27:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Y9MlAq1w"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="CspyTwQ2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6C7692173C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=n3Rcka8R2A6wGNNjrPMD3g1RtJNFPomO9q4usWzbZG4=; b=Y9MlAq1wGRd2I+ MayqXM1KptBTbsqUw1FlThzNqjK+SdvOlASsLWO57brRgnhB8e3vM0nA9amOUOuSwDyZx3AwdKO80 tCVtePRRjk+wjSGg6WdCMpd2nqVkKy+ngSV2KD/+7iPFavk/TxK2ffYWF+jzV7M1yQ0iPeEl0c+/G SxbG/w2nBNhmvIAJgcXKAXmyC+TPR3XkcZvX4U5V71JLlnr5xhyT2SzCghc+hJv21Y6SXdHcNy7Er nogLVikfXxrNkxeTQvXwTk5kcrGxqB9FM75KspofLWfbmXleF8Zmj57NlaO9auSgB2KkkqmPgeTdh EoQwqS1WbCVf5gM+Iqdw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h9uLJ-0003OU-Vo; Fri, 29 Mar 2019 16:26:57 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1h9uLH-0003O9-4i for linux-arm-kernel@lists.infradead.org; Fri, 29 Mar 2019 16:26:56 +0000 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BB4F52173C; Fri, 29 Mar 2019 16:26:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553876814; bh=Tccv/yg+5lH9K1dXNYk4rXg6MPswEtky165ALatvt9A=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CspyTwQ2USzqVg46DHPocag4nY8KdT/QVnLT8M0E7OIaedW6/tf+B1AiSWtU9FA0O DuAwMQtFu0z1dJweqTs+uobfXiwDpst7idxWjgRrNRI8GvvCpbU7PP9i/Q21d9Gnhp 9cyndw4KkMRfrNWUTlhxqPTqt+OniJ90HepBqQU8= Date: Fri, 29 Mar 2019 17:26:51 +0100 From: Greg KH To: Lingutla Chandrasekhar Subject: Re: [PATCH v2] arch_topology: Make cpu_capacity sysfs node as ready-only Message-ID: <20190329162651.GA9608@kroah.com> References: <20190328044705.16838-1-clingutla@codeaurora.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190328044705.16838-1-clingutla@codeaurora.org> User-Agent: Mutt/1.11.4 (2019-03-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190329_092655_203605_87862302 X-CRM114-Status: GOOD ( 13.80 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: catalin.marinas@arm.com, linux-kernel@vger.kernel.org, jeremy.linton@arm.com, quentin.perret@arm.com, sudeep.holla@arm.com, dietmar.eggemann@arm.com, linux-arm-kernel@lists.infradead.org, juri.lelli@gmail.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Mar 28, 2019 at 10:17:05AM +0530, Lingutla Chandrasekhar wrote: > If user updates any cpu's cpu_capacity, then the new value is going to > be applied to all its online sibling cpus. But this need not to be correct > always, as sibling cpus (in ARM, same micro architecture cpus) would have > different cpu_capacity with different performance characteristics. > So, updating the user supplied cpu_capacity to all cpu siblings > is not correct. > > And another problem is, current code assumes that 'all cpus in a cluster > or with same package_id (core_siblings), would have same cpu_capacity'. > But with commit '5bdd2b3f0f8 ("arm64: topology: add support to remove > cpu topology sibling masks")', when a cpu hotplugged out, the cpu > information gets cleared in its sibling cpus. So, user supplied > cpu_capacity would be applied to only online sibling cpus at the time. > After that, if any cpu hotplugged in, it would have different cpu_capacity > than its siblings, which breaks the above assumption. > > So, instead of mucking around the core sibling mask for user supplied > value, use device-tree to set cpu capacity. And make the cpu_capacity > node as read-only to know the asymmetry between cpus in the system. > While at it, remove cpu_scale_mutex usage, which used for sysfs write > protection. > > Tested-by: Dietmar Eggemann > Tested-by: Quentin Perret > Reviewed-by: Quentin Perret > Acked-by: Sudeep Holla > Signed-off-by: Lingutla Chandrasekhar I see 3 "v2" patches in my queue, all different :( Also, you need to list what changed below the --- line as the documentation says to do so. Please fix up and resend v3. thanks, greg k-h _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel