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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 5EF41CA0FF7 for ; Thu, 28 Aug 2025 17:28:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ejsSpIZwN3zZAh7urw29iiA/GFhtn6CB06LXQPnvnIU=; b=Q76m7L8+8iXwXpPJs1pAHzwSME q/WR9V+VCXOwRSn5zSAFYc0dgMcpnSS7FWCGPNRlcJt9GGelj4VFtF7CYgh0HRgK5sT9f+odXDFeH tkR2d1IW1NDRAMIyHaafKKMz7tyaAiCz3KPliZc5A1uIY3VsfzmckkY0C2HiwjAfO5s+l1GoNJE6H Azl89UEOQqxDkdQkIY7oSCQQNyIVsS8LGSQdfF2C2PxllCZnf9QMAC6hrFWsgQEcuTzes5ZKBSuAp Ub8Uuyd6RDQR/CEnrdh7ml9w3xt6SyKW7shAJbi9mgk0FPj9bXXmKICUr39XO+lB9SEC9nujjV3+m Czk9FRxg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1urgPk-00000002VDB-44R4; Thu, 28 Aug 2025 17:27:56 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1urdKj-00000001rQC-0uE7 for linux-arm-kernel@lists.infradead.org; Thu, 28 Aug 2025 14:10:34 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E6FF31688; Thu, 28 Aug 2025 07:10:23 -0700 (PDT) Received: from e133380.arm.com (e133380.arm.com [10.1.197.68]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 95A893F694; Thu, 28 Aug 2025 07:10:26 -0700 (PDT) Date: Thu, 28 Aug 2025 15:10:23 +0100 From: Dave Martin To: James Morse Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, devicetree@vger.kernel.org, shameerali.kolothum.thodi@huawei.com, D Scott Phillips OS , carl@os.amperecomputing.com, lcherian@marvell.com, bobo.shaobowang@huawei.com, tan.shaopeng@fujitsu.com, baolin.wang@linux.alibaba.com, Jamie Iles , Xin Hao , peternewman@google.com, dfustini@baylibre.com, amitsinght@marvell.com, David Hildenbrand , Rex Nie , Koba Ko , Shanker Donthineni , fenghuay@nvidia.com, baisheng.gao@unisoc.com, Jonathan Cameron , Rob Herring , Rohit Mathew , Rafael Wysocki , Len Brown , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Krzysztof Kozlowski , Conor Dooley , Catalin Marinas , Will Deacon , Greg Kroah-Hartman , Danilo Krummrich Subject: Re: [PATCH 02/33] drivers: base: cacheinfo: Add helper to find the cache size from cpu+level Message-ID: References: <20250822153048.2287-1-james.morse@arm.com> <20250822153048.2287-3-james.morse@arm.com> <2ac66605-ee6a-495b-a0fb-910926abd8b0@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2ac66605-ee6a-495b-a0fb-910926abd8b0@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250828_071033_330245_7260D925 X-CRM114-Status: GOOD ( 28.87 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi James, On Wed, Aug 27, 2025 at 06:11:43PM +0100, James Morse wrote: > Hi Dave, > > On 27/08/2025 11:46, Dave Martin wrote: > > Hi, > > > > On Fri, Aug 22, 2025 at 03:29:43PM +0000, James Morse wrote: > >> MPAM needs to know the size of a cache associated with a particular CPU. > >> The DT/ACPI agnostic way of doing this is to ask cacheinfo. > >> > >> Add a helper to do this. > > >> diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h > >> index 2dcbb69139e9..e12d6f2c6a57 100644 > >> --- a/include/linux/cacheinfo.h > >> +++ b/include/linux/cacheinfo.h > >> @@ -148,6 +148,21 @@ static inline int get_cpu_cacheinfo_id(int cpu, int level) > >> return ci ? ci->id : -1; > >> } > >> > >> +/** > >> + * get_cpu_cacheinfo_size() - Get the size of the cache. > >> + * @cpu: The cpu that is associated with the cache. > >> + * @level: The level of the cache as seen by @cpu. > >> + * > >> + * Callers must hold the cpuhp lock. > >> + * Returns the cache-size on success, or 0 for an error. > >> + */ > > > > Nit: Maybe use the wording > > > > cpuhp lock must be held. > > > > in the kerneldoc here, to match the other helpers it sits alongside. > > > > Otherwise, looks reasonable. > > Sure, > > > >> +static inline unsigned int get_cpu_cacheinfo_size(int cpu, int level) > >> +{ > >> + struct cacheinfo *ci = get_cpu_cacheinfo_level(cpu, level); > >> + > >> + return ci ? ci->size : 0; > >> +} > >> + > > > > Orphaned function? > > > > Can fs/resctrl/rdtgroup.c:rdtgroup_cbm_to_size() be ported to use this? > > If so, this wouldn't just be dead code in this series. > > Ah - I thought the MPAM driver was pulling this value in, but its the resctrl glue code. > I was trying to reduce the number of trees this touches - its probably best to kick this > into the next series that adds the resctrl code as its pretty trivial. > > > Thanks, > > James Sure, that also works. Cheers ---Dave