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=-5.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 F3C82C433E0 for ; Wed, 22 Jul 2020 14:18:47 +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 BDFE920729 for ; Wed, 22 Jul 2020 14:18:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="NMpBuARx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BDFE920729 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de 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=LaGr3TVuCE3PxN9AzT1jaWslPTHB3EBHs79UDAPhHUQ=; b=NMpBuARxnyTh1VLgCDTFy+tO/ 2+qe42Q0ozzEM4ZZi92hqzOFBAbIZR6O4UH3wDUxiRB1N4AxmkxRURAsJmYbIMcf9qu0QrlzzhNmu n5ONUNvD4fAhblNvltMQIlBr/Swilts5SXTgKY+7XvzSwHC16VXEl9AfquJguUaCyVrk1mhX4q4FD Q/WUo69CbYN6qgU4QGOHjGFvLOLYUXhrSqluz99r1RbSXdvls+2fm1B8j2Ka8HC3gnV8KOrdW5NrL U0BRLx9HLyYkdaCbvZuZljAsGsM5fnbFz92eOyrTtzXavh8MLiG7GR4sp+L7O1ciyXVNZ0EYqYbfu 2NZBo7c0g==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jyFYU-0003Dt-BW; Wed, 22 Jul 2020 14:17:10 +0000 Received: from verein.lst.de ([213.95.11.211]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jyFYR-0003Cy-4S for linux-arm-kernel@lists.infradead.org; Wed, 22 Jul 2020 14:17:08 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 96A4168B05; Wed, 22 Jul 2020 16:16:58 +0200 (CEST) Date: Wed, 22 Jul 2020 16:16:58 +0200 From: Christoph Hellwig To: Barry Song Subject: Re: [PATCH v3 1/2] dma-direct: provide the ability to reserve per-numa CMA Message-ID: <20200722141658.GA17658@lst.de> References: <20200628111251.19108-1-song.bao.hua@hisilicon.com> <20200628111251.19108-2-song.bao.hua@hisilicon.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200628111251.19108-2-song.bao.hua@hisilicon.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200722_101707_296536_F0AD91FB X-CRM114-Status: GOOD ( 10.78 ) 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: catalin.marinas@arm.com, Steve Capper , robin.murphy@arm.com, Jonathan Cameron , linuxarm@huawei.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Nicolas Saenz Julienne , ganapatrao.kulkarni@cavium.com, Andrew Morton , Mike Rapoport , will@kernel.org, hch@lst.de, linux-arm-kernel@lists.infradead.org, m.szyprowski@samsung.com 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 Sun, Jun 28, 2020 at 11:12:50PM +1200, Barry Song wrote: > This is useful for at least two scenarios: > 1. ARM64 smmu will get memory from local numa node, it can save its > command queues and page tables locally. Tests show it can decrease > dma_unmap latency at lot. For example, without this patch, smmu on > node2 will get memory from node0 by calling dma_alloc_coherent(), > typically, it has to wait for more than 560ns for the completion of > CMD_SYNC in an empty command queue; with this patch, it needs 240ns > only. > 2. when we set iommu passthrough, drivers will get memory from CMA, > local memory means much less latency. I really don't like the config options. With the boot parameters you can always hardcode that in CONFIG_CMDLINE anyway. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel