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=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 513FFC43461 for ; Wed, 16 Sep 2020 14:58:12 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 D420C22287 for ; Wed, 16 Sep 2020 14:58:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="uZfRQu1C" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D420C22287 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+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=merlin.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=4B/eeQ3BqHvTJNp+dM+a1nLrN1Or3TvWIHl6YJXcQOI=; b=uZfRQu1CnzvpmAZa3D34yInt/ ccGOO05BOy16gqBOaV+12jjO5DH+4CEB3qsXLk4ljQTC11PZS3jEbGQWHVAtmw00kQx1Df99ze1ax lXpTva51//cg1deYfp/2eHZ97NtY9LULnshsG41vIihDgwOcReyFRkfs9YEh154gEtuHsJ/Rah2pq hysYydu8rx7KTNcEtl7CJhctBAqSVytgkVEg/yShE6aF0boPppG+9iM2MLfB4OU/70KwDJovCoBdR WHR0CYonfdqKfU9cbZL5fK9nL+Lu92ZOoOOO4F2JFZnW7P9rQCac0PBJF0LNtmtXDdHnxZBcAG1Sr uhqz5gUaQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kIYrY-00024f-HC; Wed, 16 Sep 2020 14:56:48 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kIYrV-00023F-F6; Wed, 16 Sep 2020 14:56:46 +0000 Received: from gaia (unknown [46.69.195.48]) (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 902F222283; Wed, 16 Sep 2020 14:56:42 +0000 (UTC) Date: Wed, 16 Sep 2020 15:56:40 +0100 From: Catalin Marinas To: Phil Chang Subject: Re: [PATCH] [PATCH] ARM64: Setup DMA32 zone size by bootargs Message-ID: <20200916145639.GC3122@gaia> References: <20200916083703.GA26411@infradead.org> <20200916133324.6280-1-phil.chang@mediatek.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200916133324.6280-1-phil.chang@mediatek.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200916_105645_616204_CBCB4CAC X-CRM114-Status: GOOD ( 16.35 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Alix Wu , Anshuman Khandual , Mauro Carvalho Chehab , YJ Chiang , Jonathan Corbet , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org, Mike Rapoport , Will Deacon , 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+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Sep 16, 2020 at 09:33:24PM +0800, Phil Chang wrote: > this patch allowing the DMA32 zone be configurable in ARM64. > For some devices, the main memory split into 2 part due to the memory > architecture, the efficient and less inefficient part. > One of the use case is fine-tune the dma32 size to contain all the > efficient part of memory block on this kind of architecture > > Signed-off-by: Alix Wu > Signed-off-by: YJ Chiang > Signed-off-by: Phil Chang > --- > Hi > > supplement the reason of this usage. That's really not a good enough justification to merge such patch. As Christoph said, DMA32 is defined as addressing the first 4GB of RAM. Is the memory inefficient (presumably slow) for device or for the CPU? Maybe you can pretend it's a separate NUMA node for the CPU. Alternatively, change your device DMA coherent mask and allocate only from ZONE_DMA (currently first 1GB on arm64). -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel