From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Date: Fri, 27 Aug 2021 18:47:36 +0000 Subject: [Cluster-devel] [PATCH v7 18/19] iov_iter: Introduce nofault flag to disable page faults In-Reply-To: <20210827164926.1726765-19-agruenba@redhat.com> References: <20210827164926.1726765-1-agruenba@redhat.com> <20210827164926.1726765-19-agruenba@redhat.com> Message-ID: List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Fri, Aug 27, 2021 at 06:49:25PM +0200, Andreas Gruenbacher wrote: > Introduce a new nofault flag to indicate to get_user_pages to use the > FOLL_NOFAULT flag. This will cause get_user_pages to fail when it > would otherwise fault in a page. > > Currently, the noio flag is only checked in iov_iter_get_pages and > iov_iter_get_pages_alloc. This is enough for iomaop_dio_rw, but it > may make sense to check in other contexts as well. I can live with that, but * direct assignments (as in the next patch) are fucking hard to grep for. Is it intended to be "we set it for duration of primitive", or...? * it would be nice to have a description of intended semantics for that thing. This "may make sense to check in other contexts" really needs to be elaborated (and agreed) upon. Details, please. 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Fri, 27 Aug 2021 11:52:06 -0700 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 17RInrUa035390 for ; Fri, 27 Aug 2021 18:52:06 GMT Received: from mx0b-00069f01.pphosted.com (mx0b-00069f01.pphosted.com [205.220.177.26]) by userp3030.oracle.com with ESMTP id 3ajpm56895-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Fri, 27 Aug 2021 18:52:06 +0000 Received: from pps.filterd (m0246580.ppops.net [127.0.0.1]) by mx0b-00069f01.pphosted.com (8.16.1.2/8.16.0.43) with SMTP id 17RDkkHd016243 for ; Fri, 27 Aug 2021 18:52:05 GMT Received: from zeniv-ca.linux.org.uk (zeniv-ca.linux.org.uk [142.44.231.140]) by mx0b-00069f01.pphosted.com with ESMTP id 3aq17p3b0h-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO) for ; Fri, 27 Aug 2021 18:52:04 +0000 Received: from viro by zeniv-ca.linux.org.uk with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mJgt6-00GYzg-NV; Fri, 27 Aug 2021 18:47:36 +0000 Date: Fri, 27 Aug 2021 18:47:36 +0000 From: Al Viro To: Andreas Gruenbacher Message-ID: References: <20210827164926.1726765-1-agruenba@redhat.com> <20210827164926.1726765-19-agruenba@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210827164926.1726765-19-agruenba@redhat.com> X-Source-IP: 142.44.231.140 X-ServerName: zeniv-ca.linux.org.uk X-Proofpoint-SPF-Result: None X-Proofpoint-Virus-Version: vendor=nai engine=6300 definitions=10089 signatures=668682 X-Proofpoint-Spam-Details: rule=tap_notspam policy=tap score=0 adultscore=0 clxscore=192 bulkscore=0 mlxscore=0 mlxlogscore=429 lowpriorityscore=0 priorityscore=0 phishscore=0 spamscore=0 malwarescore=0 impostorscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2107140000 definitions=main-2108270109 domainage_hfrom=9157 X-Spam: Clean X-Proofpoint-Virus-Version: vendor=nai engine=6300 definitions=10089 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 phishscore=0 malwarescore=0 mlxscore=0 bulkscore=0 mlxlogscore=480 suspectscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2107140000 definitions=main-2108270109 Cc: cluster-devel@redhat.com, Jan Kara , linux-kernel@vger.kernel.org, Christoph Hellwig , linux-fsdevel@vger.kernel.org, Linus Torvalds , ocfs2-devel@oss.oracle.com Subject: Re: [Ocfs2-devel] [PATCH v7 18/19] iov_iter: Introduce nofault flag to disable page faults X-BeenThere: ocfs2-devel@oss.oracle.com X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: ocfs2-devel-bounces@oss.oracle.com Errors-To: ocfs2-devel-bounces@oss.oracle.com X-Proofpoint-Virus-Version: vendor=nai engine=6300 definitions=10089 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 phishscore=0 malwarescore=0 mlxscore=0 bulkscore=0 mlxlogscore=999 suspectscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2107140000 definitions=main-2108270109 X-Proofpoint-GUID: 34BBUreVSOay9V1cOiVaPGEmQlCHcGuZ X-Proofpoint-ORIG-GUID: 34BBUreVSOay9V1cOiVaPGEmQlCHcGuZ On Fri, Aug 27, 2021 at 06:49:25PM +0200, Andreas Gruenbacher wrote: > Introduce a new nofault flag to indicate to get_user_pages to use the > FOLL_NOFAULT flag. This will cause get_user_pages to fail when it > would otherwise fault in a page. > > Currently, the noio flag is only checked in iov_iter_get_pages and > iov_iter_get_pages_alloc. This is enough for iomaop_dio_rw, but it > may make sense to check in other contexts as well. I can live with that, but * direct assignments (as in the next patch) are fucking hard to grep for. Is it intended to be "we set it for duration of primitive", or...? * it would be nice to have a description of intended semantics for that thing. This "may make sense to check in other contexts" really needs to be elaborated (and agreed) upon. Details, please. _______________________________________________ Ocfs2-devel mailing list Ocfs2-devel@oss.oracle.com https://oss.oracle.com/mailman/listinfo/ocfs2-devel 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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 D4822C432BE for ; Fri, 27 Aug 2021 18:52:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ADD6160FDA for ; Fri, 27 Aug 2021 18:52:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230284AbhH0Sww (ORCPT ); Fri, 27 Aug 2021 14:52:52 -0400 Received: from zeniv-ca.linux.org.uk ([142.44.231.140]:42272 "EHLO zeniv-ca.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230084AbhH0Swv (ORCPT ); Fri, 27 Aug 2021 14:52:51 -0400 Received: from viro by zeniv-ca.linux.org.uk with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mJgt6-00GYzg-NV; Fri, 27 Aug 2021 18:47:36 +0000 Date: Fri, 27 Aug 2021 18:47:36 +0000 From: Al Viro To: Andreas Gruenbacher Cc: Linus Torvalds , Christoph Hellwig , "Darrick J. Wong" , Jan Kara , Matthew Wilcox , cluster-devel@redhat.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, ocfs2-devel@oss.oracle.com Subject: Re: [PATCH v7 18/19] iov_iter: Introduce nofault flag to disable page faults Message-ID: References: <20210827164926.1726765-1-agruenba@redhat.com> <20210827164926.1726765-19-agruenba@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210827164926.1726765-19-agruenba@redhat.com> Sender: Al Viro Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, Aug 27, 2021 at 06:49:25PM +0200, Andreas Gruenbacher wrote: > Introduce a new nofault flag to indicate to get_user_pages to use the > FOLL_NOFAULT flag. This will cause get_user_pages to fail when it > would otherwise fault in a page. > > Currently, the noio flag is only checked in iov_iter_get_pages and > iov_iter_get_pages_alloc. This is enough for iomaop_dio_rw, but it > may make sense to check in other contexts as well. I can live with that, but * direct assignments (as in the next patch) are fucking hard to grep for. Is it intended to be "we set it for duration of primitive", or...? * it would be nice to have a description of intended semantics for that thing. This "may make sense to check in other contexts" really needs to be elaborated (and agreed) upon. Details, please.