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=-3.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_NEOMUTT 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 74014C43219 for ; Sat, 27 Apr 2019 16:12:55 +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 3BB92206C1 for ; Sat, 27 Apr 2019 16:12:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="GQUZg8Er" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3BB92206C1 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com 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=3M8LYMLVQOSzpzv7MdR1t3zdp19vuvsgW3D7C28aeSY=; b=GQUZg8Er/g+eIR Gq4AO7gSN5Inh35DuAL8dmHevh3fCpjRV19eOSnUwnJvreMNmSs6pEtpKs3ZAJV3ciV2kIKlM22jM 7GVdRsggmk4rFqQCXwpgR9TgVoXyBRx4Y43WRlfN9PiVPDEm7Hnfs5qdVeHwMtBsyR68RjSQJUGO4 jsj/8evoK3pQNgtvNdDnVbSl/Ch+sZM4xw6cdGvNWp0dCzdrw0DKuxNBozlwr/zscfZJ1KPkgF++h ihK9Dt3K9TK775d96se9joFztt8UEJXGxO123lYmMJWqwfwAHLN2Jm2j0M8EmZRq2tp1m+3gntH2t PtYZvVEfQtRU7EFFC9tA==; 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 1hKPwc-00014l-32; Sat, 27 Apr 2019 16:12:54 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hKPwZ-00014C-Bh for linux-arm-kernel@lists.infradead.org; Sat, 27 Apr 2019 16:12:52 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6D66B80D; Sat, 27 Apr 2019 09:12:48 -0700 (PDT) Received: from mbp (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 10EEE3F246; Sat, 27 Apr 2019 09:12:46 -0700 (PDT) Date: Sat, 27 Apr 2019 17:12:44 +0100 From: Catalin Marinas To: Jeremy Linton Subject: Re: [PATCH 2/2] arm64: cacheinfo: Update cache_line_size detected from PPTT Message-ID: <20190427161243.6674yszyflgjqbhc@mbp> References: <1556242821-5080-1-git-send-email-zhangshaokun@hisilicon.com> <1556242821-5080-2-git-send-email-zhangshaokun@hisilicon.com> <8d9b4fcd-23be-be06-6afa-8cabb1e889c2@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <8d9b4fcd-23be-be06-6afa-8cabb1e889c2@arm.com> User-Agent: NeoMutt/20170113 (1.7.2) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190427_091251_407419_BB037196 X-CRM114-Status: GOOD ( 14.28 ) 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: john.garry@huawei.com, Will Deacon , Shaokun Zhang , qiuzhenfa@hisilicon.com, guohanjun@huawei.com, linux-arm-kernel@lists.infradead.org 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 Fri, Apr 26, 2019 at 12:18:33PM -0500, Jeremy Linton wrote: > On 4/25/19 8:40 PM, Shaokun Zhang wrote: > > cache_line_size is derived from CTR_EL0.CWG field and is called mostly > > for I/O device drivers. For HiSilicon certain plantform, like the > > But there are core users too? Thinkgs like blk-mq, the trace ring buffer, > iommu/iova, slub/slab. cache_line_size() is indeed used in the core parts of the kernel, for example when passing SLAB_HWCACHE_ALIGN on kmem_cache creation. Its meaning is performance rather than coherency as we use ARCH_DMA_MINALIGN for the latter. > And a quick look seems to indicate a number of those > users are going to be checking the cache line size before the cachinfo is > populated (it happens fairly late via device_initcall() and a hp notifier). > Is it going to be a problem if the value changes? That's a good point. At a quick look I didn't see anything that would be affected by a non-constant cache_line_size(). -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel