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 BEAF2C43219 for ; Mon, 29 Apr 2019 11:06:58 +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 749D620673 for ; Mon, 29 Apr 2019 11:06:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="NTh61pst" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 749D620673 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=iZfyOQEeSDqZaYdU1cj52xbJyaH0NtORVKRatjN/FZU=; b=NTh61pst4nhB5v nooxYDmnq5ccWQpiyH6YZEqGunRck5GX+bRidw3cVRNByPODE+Jf2G8LzAB0DclaGWQZKJaDp63M3 BkMLhaD0ZGA81y8/9ALA1BmUHcFRq+DbBTlf7avPBVrSzysjzr0jpnH1PBojWfGHV2WMLVerZVLYt xOCD8bvp3dFCEXi3qwVt7e42dLlx8Zf/vcp2ZWPvxzyIRdz/zw6pSF6AjyFmyv58UWnDuCnKYMloj AU9U4VuVLp0xvn26p5711uLmqM4Mk5I6RhK4YIuwZCyOIaYIqbFRy3QYNxOqBh+m1To1h3YYBsRm2 qUGdo/yk6gd1IElgb7QQ==; 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 1hL47U-0000VQ-Sv; Mon, 29 Apr 2019 11:06:48 +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 1hL47S-0000V2-1d for linux-arm-kernel@lists.infradead.org; Mon, 29 Apr 2019 11:06:47 +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 02F9F80D; Mon, 29 Apr 2019 04:06:43 -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 47FA03F5AF; Mon, 29 Apr 2019 04:06:41 -0700 (PDT) Date: Mon, 29 Apr 2019 12:06:36 +0100 From: Sudeep Holla To: Jeremy Linton Subject: Re: [PATCH 2/2] arm64: cacheinfo: Update cache_line_size detected from PPTT Message-ID: <20190429110453.GA23929@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> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <8d9b4fcd-23be-be06-6afa-8cabb1e889c2@arm.com> 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_040646_089671_A670EA1F X-CRM114-Status: GOOD ( 15.04 ) 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 , Catalin Marinas , 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: > Hi, > > 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. 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? > Yes, I agree with that and share the same concern. If the users of these can't get updated with the new value once cacheinfo is populated, then we need to figure to solve this differently(I mean still from PPTT or firmware info as we don't have anything more reliable). -- Regards, Sudeep _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel