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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 10CDEC433EF for ; Sun, 8 Sep 2019 21:27:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DE180216C8 for ; Sun, 8 Sep 2019 21:27:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730815AbfIHV1R (ORCPT ); Sun, 8 Sep 2019 17:27:17 -0400 Received: from foss.arm.com ([217.140.110.172]:43278 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727235AbfIHV1R (ORCPT ); Sun, 8 Sep 2019 17:27:17 -0400 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 C23C2337; Sun, 8 Sep 2019 14:27:16 -0700 (PDT) Received: from huawei_p9_lite.cambridge.arm.com (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AC4243F67D; Sun, 8 Sep 2019 14:27:13 -0700 (PDT) Date: Sun, 8 Sep 2019 22:27:11 +0100 From: Catalin Marinas To: Nicolas Saenz Julienne Cc: hch@lst.de, wahrenst@gmx.net, marc.zyngier@arm.com, robh+dt@kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, Will Deacon , f.fainelli@gmail.com, robin.murphy@arm.com, linux-kernel@vger.kernel.org, mbrugger@suse.com, linux-rpi-kernel@lists.infradead.org, phill@raspberrypi.org, m.szyprowski@samsung.com Subject: Re: [PATCH v4 3/4] arm64: use both ZONE_DMA and ZONE_DMA32 Message-ID: <20190908212711.GA84759@huawei_p9_lite.cambridge.arm.com> References: <20190906120617.18836-1-nsaenzjulienne@suse.de> <20190906120617.18836-4-nsaenzjulienne@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190906120617.18836-4-nsaenzjulienne@suse.de> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 06, 2019 at 02:06:14PM +0200, Nicolas Saenz Julienne wrote: > @@ -430,7 +454,7 @@ void __init arm64_memblock_init(void) > > high_memory = __va(memblock_end_of_DRAM() - 1) + 1; > > - dma_contiguous_reserve(arm64_dma32_phys_limit); > + dma_contiguous_reserve(arm64_dma_phys_limit ? : arm64_dma32_phys_limit); > } > > void __init bootmem_init(void) > @@ -534,6 +558,7 @@ static void __init free_unused_memmap(void) > void __init mem_init(void) > { > if (swiotlb_force == SWIOTLB_FORCE || > + max_pfn > (arm64_dma_phys_limit >> PAGE_SHIFT) || > max_pfn > (arm64_dma32_phys_limit >> PAGE_SHIFT)) > swiotlb_init(1); So here we want to initialise the swiotlb only if we need bounce buffers. Prior to this patch, we assumed that swiotlb is needed if max_pfn is beyond the reach of 32-bit devices. With ZONE_DMA, we need to lower this limit to arm64_dma_phys_limit. If ZONE_DMA is enabled, just comparing max_pfn with arm64_dma_phys_limit is sufficient since the dma32 one limit always higher. However, if ZONE_DMA is disabled, arm64_dma_phys_limit is 0, so we may initialise swiotlb unnecessarily. I guess you need a similar check to the dma_contiguous_reserve() above. With that: Reviewed-by: Catalin Marinas Unless there are other objections, I can queue this series for 5.5 in a few weeks time (too late for 5.4). -- Catalin