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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, 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 DDCBCC43219 for ; Mon, 29 Apr 2019 11:12:18 +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 AD9E52087B for ; Mon, 29 Apr 2019 11:12:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="E/It9dMS" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AD9E52087B 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=4lADaBP/dc6yHcQWgqvMt/EtpA4wLQg1gCAtwEekl6g=; b=E/It9dMSmX5Bcp UwKo2DxM75MJlLXMiu/aSz7GTXn6Dy4RVLy2lD2IKcUyTuHYRpAuFi6xsQxTmJ/g4R5Hd5pNJmlSQ 7SN56h9lKDHJETO71oCNUE1RXaZ6Y0i0WVpGu89atY9eA8ucj8eS5Z6CG5j+24OMYf36SZSZKuYPn DBCIsRxKXeTN5adIBW48yG9MUTcOdGixxv6wClkqAIlTNDTnZu4GqjoS/Gx85GzCz+lPmUe+2A4gX h6WbPjs1WzdB+PAtd+OyHYZN+bEDHQ6EazqyGj6cuj2hMzeGL8SUdQtrGoiO1IStaDoc90mtB9dds e0A3sezmKSjoFpQYsmtw==; 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 1hL4Cn-0002zZ-NY; Mon, 29 Apr 2019 11:12:17 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hL4Cl-0002zB-1A for linux-arm-kernel@lists.infradead.org; Mon, 29 Apr 2019 11:12:16 +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 8F5C280D; Mon, 29 Apr 2019 04:12:14 -0700 (PDT) Received: from e107155-lin (e107155-lin.cambridge.arm.com [10.1.196.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D5EB13F5AF; Mon, 29 Apr 2019 04:12:12 -0700 (PDT) Date: Mon, 29 Apr 2019 12:12:10 +0100 From: Sudeep Holla To: Catalin Marinas Subject: Re: [PATCH 2/2] arm64: cacheinfo: Update cache_line_size detected from PPTT Message-ID: <20190429111210.GB23929@e107155-lin> 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> <20190427161243.6674yszyflgjqbhc@mbp> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190427161243.6674yszyflgjqbhc@mbp> User-Agent: Mutt/1.9.4 (2018-02-28) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190429_041215_083282_63AC13C0 X-CRM114-Status: GOOD ( 18.74 ) 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: Sudeep Holla , john.garry@huawei.com, Will Deacon , Jeremy Linton , 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 Sat, Apr 27, 2019 at 05:12:44PM +0100, Catalin Marinas wrote: > 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(). > Ah, that's good. But won't it still affect early boot allocations(if the smaller init time value is used before cacheinfo is populated) ? Sorry, I haven't looked at all the uses of cache_line_size(). But if cache_line_size() takes care of reading updated value and impact on boot time allocations are minimal, then this solution should be fine. -- Regards, Sudeep _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel