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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 A0C3AC2BCA1 for ; Fri, 7 Jun 2019 15:10:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 77B1B2089E for ; Fri, 7 Jun 2019 15:10:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="WYsyLuJw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729865AbfFGPKT (ORCPT ); Fri, 7 Jun 2019 11:10:19 -0400 Received: from mail-qt1-f194.google.com ([209.85.160.194]:41384 "EHLO mail-qt1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729850AbfFGPKQ (ORCPT ); Fri, 7 Jun 2019 11:10:16 -0400 Received: by mail-qt1-f194.google.com with SMTP id s57so2627752qte.8 for ; Fri, 07 Jun 2019 08:10:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=mtF5cAWsrYgtNZcy7Xm0z7hOgyvsIAMepLY84jhBIIY=; b=WYsyLuJwZJIQkQf8wUWCq+MKSRiYgAlB3cZg5uiR6sfXzmT5qRPbG9DhevssrlPWqT btVD4AS17pELyqwsgZDkQw2P7FuITtTVQMrN8ttsGMNW1xgfpIRPBVOa0vjh1b2Q1GR1 KuOwYeQwWnuz6D+1FRguaiqcVs7bzdSKLArmkC9S3JiLqJpGoQtRUAt5WZRIgTPnLny4 IKSY1gSwXGY6RvgI08IKQsXM6qG3PGhAf3b+OAJpaapDK96fRJ2kOM5Yvdls9VHMdofH LPFgCkV+imozC4VVLOAwHIKBZyqQ6Svl+UIUCGPXrQKi5OfcTa6MmnRnnxQ4x38JcA+k g4gw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=mtF5cAWsrYgtNZcy7Xm0z7hOgyvsIAMepLY84jhBIIY=; b=AGiyyNgjyrJpKaLnFTJNsSGNOctbb6KFER5TpVIWJ3l8EK41t3fDPebPdH0AGTw0as WUkaYkQ3Z5HB8k4bTg8ov8my7RhgMvCe58nlUE4un42DBc1qKSRzRh1/lwQudTW9/EOK qULYdhdEy8m0sLftoNYFP/cIXW9cooegYADTBsOdSwLDgq6R1jZUB4mKhhYAsZ1xV0KO kadQicqRMfyYyA5liuxly5m0TsAtt6v5LRrtJFHTLoLbTM/2znnAZxmczGggaLGImn8P FFSlMcG4jbfnkL0sLPdwQluqZ/36tVAGd2YOGoRGGWLIqcFSkTkxiCLd+geM8b2OoSm9 O0pA== X-Gm-Message-State: APjAAAXsda7r3b+obhWWwIDPt2xKHKOWMXP0J7Rnz4A234c+tExj1ABy O2Dyuypu1MDSPniKjwLTdb3JmQ== X-Google-Smtp-Source: APXvYqz98pAEW8JOYRDiw9EYF+WsmnpCH5t6BgflMJ4duW3xWG4TSqN3U+4KRrwB7XAG90R+0pkeHA== X-Received: by 2002:ac8:4619:: with SMTP id p25mr14877922qtn.73.1559920216042; Fri, 07 Jun 2019 08:10:16 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-156-34-55-100.dhcp-dynamic.fibreop.ns.bellaliant.net. [156.34.55.100]) by smtp.gmail.com with ESMTPSA id a11sm1103592qkn.26.2019.06.07.08.10.15 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 07 Jun 2019 08:10:15 -0700 (PDT) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1hZGVT-0006TX-4L; Fri, 07 Jun 2019 12:10:15 -0300 Date: Fri, 7 Jun 2019 12:10:15 -0300 From: Jason Gunthorpe To: Ira Weiny Cc: Jan Kara , Dan Williams , Theodore Ts'o , Jeff Layton , Dave Chinner , Matthew Wilcox , linux-xfs@vger.kernel.org, Andrew Morton , John Hubbard , =?utf-8?B?SsOpcsO0bWU=?= Glisse , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, linux-ext4@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH RFC 00/10] RDMA/FS DAX truncate proposal Message-ID: <20190607151015.GJ14802@ziepe.ca> References: <20190606014544.8339-1-ira.weiny@intel.com> <20190606104203.GF7433@quack2.suse.cz> <20190606195114.GA30714@ziepe.ca> <20190606222228.GB11698@iweiny-DESK2.sc.intel.com> <20190607103636.GA12765@quack2.suse.cz> <20190607121729.GA14802@ziepe.ca> <20190607145213.GB14559@iweiny-DESK2.sc.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190607145213.GB14559@iweiny-DESK2.sc.intel.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 07, 2019 at 07:52:13AM -0700, Ira Weiny wrote: > On Fri, Jun 07, 2019 at 09:17:29AM -0300, Jason Gunthorpe wrote: > > On Fri, Jun 07, 2019 at 12:36:36PM +0200, Jan Kara wrote: > > > > > Because the pins would be invisible to sysadmin from that point on. > > > > It is not invisible, it just shows up in a rdma specific kernel > > interface. You have to use rdma netlink to see the kernel object > > holding this pin. > > > > If this visibility is the main sticking point I suggest just enhancing > > the existing MR reporting to include the file info for current GUP > > pins and teaching lsof to collect information from there as well so it > > is easy to use. > > > > If the ownership of the lease transfers to the MR, and we report that > > ownership to userspace in a way lsof can find, then I think all the > > concerns that have been raised are met, right? > > I was contemplating some new lsof feature yesterday. But what I don't think we > want is sysadmins to have multiple tools for multiple subsystems. Or even have > to teach lsof something new for every potential new subsystem user of GUP pins. Well.. it is a bit tricky, but you'd have to arrange for the lease object to have a list of 'struct files' that are holding the lease open. The first would be the file that did the fcntl, the next would be all the files that did longterm GUP - which means longterm GUP has to have a chardev file/etc as well (seems OK) Then lsof could query the list of lease objects for each file it encounters and print them out too. Jason