From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 4/7] dma-direct: provide generic support for uncached kernel segments Date: Wed, 1 May 2019 19:49:05 +0200 Message-ID: <20190501174905.GA20458@lst.de> References: <20190430110032.25301-1-hch@lst.de> <20190430110032.25301-5-hch@lst.de> <20190501171857.chfxqntvm6r4xrr4@pburton-laptop> <20190501172912.GA19375@lst.de> <20190501174033.6rj5aiopdeo4uqpw@pburton-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20190501174033.6rj5aiopdeo4uqpw@pburton-laptop> Sender: linux-kernel-owner@vger.kernel.org To: Paul Burton Cc: Christoph Hellwig , Ralf Baechle , James Hogan , Ley Foon Tan , Michal Simek , Bartlomiej Zolnierkiewicz , "linux-mips@vger.kernel.org" , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" , "linux-fbdev@vger.kernel.org" List-Id: iommu@lists.linux-foundation.org On Wed, May 01, 2019 at 05:40:34PM +0000, Paul Burton wrote: > > > If it is necessary then as-is this code will clear the allocated memory > > > using uncached writes which will be pretty slow. It would be much more > > > efficient to perform the memset before arch_dma_prep_coherent() & before > > > converting ret to an uncached address. > > > > Yes, we could do that. > > Great; using cached writes would match the existing MIPS behavior. Can you test the stack with the two updated patches and ack them if they are fine? That would allow getting at least the infrastructure and mips in for this merge window. 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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,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 4A563C43219 for ; Wed, 1 May 2019 17:50:08 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (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 1EABE2063F for ; Wed, 1 May 2019 17:50:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1EABE2063F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id B8D2A2B42; Wed, 1 May 2019 17:50:07 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 6D80D2B3D for ; Wed, 1 May 2019 17:49:24 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from newverein.lst.de (verein.lst.de [213.95.11.211]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 08D43711 for ; Wed, 1 May 2019 17:49:23 +0000 (UTC) Received: by newverein.lst.de (Postfix, from userid 2407) id BB11B68AFE; Wed, 1 May 2019 19:49:05 +0200 (CEST) Date: Wed, 1 May 2019 19:49:05 +0200 From: Christoph Hellwig To: Paul Burton Subject: Re: [PATCH 4/7] dma-direct: provide generic support for uncached kernel segments Message-ID: <20190501174905.GA20458@lst.de> References: <20190430110032.25301-1-hch@lst.de> <20190430110032.25301-5-hch@lst.de> <20190501171857.chfxqntvm6r4xrr4@pburton-laptop> <20190501172912.GA19375@lst.de> <20190501174033.6rj5aiopdeo4uqpw@pburton-laptop> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190501174033.6rj5aiopdeo4uqpw@pburton-laptop> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: Michal Simek , Bartlomiej Zolnierkiewicz , James Hogan , "linux-mips@vger.kernel.org" , Ralf Baechle , "linux-kernel@vger.kernel.org" , "iommu@lists.linux-foundation.org" , "linux-fbdev@vger.kernel.org" , Ley Foon Tan , Christoph Hellwig X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org Message-ID: <20190501174905.6GKykxZXcEtZs5yK4PePHu9HW95v-fHq_OWbpaQKquI@z> On Wed, May 01, 2019 at 05:40:34PM +0000, Paul Burton wrote: > > > If it is necessary then as-is this code will clear the allocated memory > > > using uncached writes which will be pretty slow. It would be much more > > > efficient to perform the memset before arch_dma_prep_coherent() & before > > > converting ret to an uncached address. > > > > Yes, we could do that. > > Great; using cached writes would match the existing MIPS behavior. Can you test the stack with the two updated patches and ack them if they are fine? That would allow getting at least the infrastructure and mips in for this merge window. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu