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=-1.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS 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 E6AB4C2BC61 for ; Tue, 30 Oct 2018 02:52:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3E0DC21019 for ; Tue, 30 Oct 2018 02:52:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="3zi0eS2j" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3E0DC21019 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726563AbeJ3Lng (ORCPT ); Tue, 30 Oct 2018 07:43:36 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:36556 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726040AbeJ3Lng (ORCPT ); Tue, 30 Oct 2018 07:43:36 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w9U2mcA3091147; Tue, 30 Oct 2018 02:51:54 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=4Zievn0L5ba1Ow40nAHHfrEZPZ4Ar5ufeUc2x/g91yg=; b=3zi0eS2jGk1Y1I6jWidMXO2b1zijPOgvh0hnraQQ23I+Gen9bYswv0mhx2lkRRAxAeQL FSGczX/c0zSS3wGbiTG/SGFOOcx5KCHWZ4h1c9RO49ygiqAJj+6WnL9L1zGdJGOC7JUf yRl9GtLV3JIn2wZHEUiWl1ie7NworcROMZIohDym5MNop2Kh6uRGz2Z1mYodKNntykQT MfNUIgHqFjdv0L5fC+Np4EofjTmD79Rx/EHCnjB3S8GBAwtzrdclLT8SYi1zNH5UTi4t nUPW/XY1JQP64PA171D+JndejYS/nH2T2J5PHuQHkVm0b9Y8eqiFdUC5xa2QzLrVchr5 yw== Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by userp2120.oracle.com with ESMTP id 2ncgnqs8v2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 30 Oct 2018 02:51:54 +0000 Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w9U2psPD016960 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 30 Oct 2018 02:51:54 GMT Received: from abhmp0016.oracle.com (abhmp0016.oracle.com [141.146.116.22]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w9U2prns022690; Tue, 30 Oct 2018 02:51:53 GMT Received: from [10.0.0.83] (/73.231.240.86) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 29 Oct 2018 19:51:52 -0700 Subject: Re: [PATCH] xen-swiotlb: exchange memory with Xen only when pages are contiguous To: Boris Ostrovsky , Konrad Rzeszutek Wilk Cc: "DONGLI.ZHANG" , konrad@kernel.org, Christoph Helwig , John Sobecki , "xen-devel@lists.xenproject.org" , "linux-kernel@vger.kernel.org\"" References: <20181024130246.GA22616@localhost.localdomain> <83900cf4-690c-9725-d022-d427fdeb4f7d@oracle.com> <581cb7ea-3112-791d-918d-9bb887e4744f@oracle.com> <24a62522-1629-5d0b-398e-6d2c1a0b97f7@oracle.com> <922914c9-22db-c5d1-33da-d07691ebd7d7@oracle.com> <45f5ffe8-3f48-4485-53f0-5a056be69b0c@oracle.com> <5b64850f-9142-0360-fe4e-9e7bc74d2368@oracle.com> From: Joe Jin Message-ID: <3e65208c-cb11-d918-00eb-012a97e56fec@oracle.com> Date: Mon, 29 Oct 2018 19:51:51 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <5b64850f-9142-0360-fe4e-9e7bc74d2368@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9061 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=2 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1810300023 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/25/18 11:56 AM, Joe Jin wrote: > I just discussed this patch with Boris in private, his opinions(Boris, > please correct me if any misunderstood) are: > > 1. With/without the check, both are incorrect, he thought we need to > prevented unalloc'd free at here. > 2. On freeing, if upper layer already checked the memory was DMA-able, > the checking at here does not make sense, we can remove all checks. > 3. xen_create_contiguous_region() and xen_destroy_contiguous_region() > to come in pairs. I tried to added radix_tree to track allocating/freeing and I found some memory only allocated but was not freed, I guess it caused by driver used dma_pool, that means if lots of such requests, the list will consume lot of memory for it. Will continue to work on it, if anyone have good idea for it please let me know, I'd like to try it. Thanks, Joe