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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1DB29C433F5 for ; Sat, 19 Feb 2022 10:18:35 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8EF396B0074; Sat, 19 Feb 2022 05:18:34 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 89F2A6B0075; Sat, 19 Feb 2022 05:18:34 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7667F6B0078; Sat, 19 Feb 2022 05:18:34 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0219.hostedemail.com [216.40.44.219]) by kanga.kvack.org (Postfix) with ESMTP id 6A2D16B0074 for ; Sat, 19 Feb 2022 05:18:34 -0500 (EST) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 196F08249980 for ; Sat, 19 Feb 2022 10:18:34 +0000 (UTC) X-FDA: 79159130148.24.ED6F12D Received: from lgeamrelo11.lge.com (lgeamrelo13.lge.com [156.147.23.53]) by imf04.hostedemail.com (Postfix) with ESMTP id 8874640007 for ; Sat, 19 Feb 2022 10:18:31 +0000 (UTC) Received: from unknown (HELO lgeamrelo01.lge.com) (156.147.1.125) by 156.147.23.53 with ESMTP; 19 Feb 2022 19:18:28 +0900 X-Original-SENDERIP: 156.147.1.125 X-Original-MAILFROM: byungchul.park@lge.com Received: from unknown (HELO X58A-UD3R) (10.177.244.38) by 156.147.1.125 with ESMTP; 19 Feb 2022 19:18:28 +0900 X-Original-SENDERIP: 10.177.244.38 X-Original-MAILFROM: byungchul.park@lge.com Date: Sat, 19 Feb 2022 19:18:20 +0900 From: Byungchul Park To: Steven Rostedt Cc: Theodore Ts'o , torvalds@linux-foundation.org, damien.lemoal@opensource.wdc.com, linux-ide@vger.kernel.org, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, mingo@redhat.com, linux-kernel@vger.kernel.org, peterz@infradead.org, will@kernel.org, tglx@linutronix.de, joel@joelfernandes.org, sashal@kernel.org, daniel.vetter@ffwll.ch, chris@chris-wilson.co.uk, duyuyang@gmail.com, johannes.berg@intel.com, tj@kernel.org, willy@infradead.org, david@fromorbit.com, amir73il@gmail.com, bfields@fieldses.org, gregkh@linuxfoundation.org, kernel-team@lge.com, linux-mm@kvack.org, akpm@linux-foundation.org, mhocko@kernel.org, minchan@kernel.org, hannes@cmpxchg.org, vdavydov.dev@gmail.com, sj@kernel.org, jglisse@redhat.com, dennis@kernel.org, cl@linux.com, penberg@kernel.org, rientjes@google.com, vbabka@suse.cz, ngupta@vflare.org, linux-block@vger.kernel.org, axboe@kernel.dk, paolo.valente@linaro.org, josef@toxicpanda.com, linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, jack@suse.cz, jack@suse.com, jlayton@kernel.org, dan.j.williams@intel.com, hch@infradead.org, djwong@kernel.org, dri-devel@lists.freedesktop.org, airlied@linux.ie, rodrigosiqueiramelo@gmail.com, melissa.srw@gmail.com, hamohammed.sa@gmail.com Subject: Re: [PATCH 00/16] DEPT(Dependency Tracker) Message-ID: <20220219101820.GC10342@X58A-UD3R> References: <1645095472-26530-1-git-send-email-byungchul.park@lge.com> <20220217120005.67f5ddf4@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220217120005.67f5ddf4@gandalf.local.home> User-Agent: Mutt/1.5.21 (2010-09-15) X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 8874640007 X-Rspam-User: Authentication-Results: imf04.hostedemail.com; dkim=none; spf=pass (imf04.hostedemail.com: domain of byungchul.park@lge.com designates 156.147.23.53 as permitted sender) smtp.mailfrom=byungchul.park@lge.com; dmarc=none X-Stat-Signature: otzn7nh45fp75tui8j1tphfntjtnkutr X-HE-Tag: 1645265911-357792 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Feb 17, 2022 at 12:00:05PM -0500, Steven Rostedt wrote: > On Thu, 17 Feb 2022 10:51:09 -0500 > "Theodore Ts'o" wrote: > > > I know that you're trying to help us, but this tool needs to be far > > better than Lockdep before we should think about merging it. Even if > > it finds 5% more potential deadlocks, if it creates 95% more false > > positive reports --- and the ones it finds are crazy things that > > rarely actually happen in practice, are the costs worth the benefits? > > And who is bearing the costs, and who is receiving the benefits? > > I personally believe that there's potential that this can be helpful and we > will want to merge it. > > But, what I believe Ted is trying to say is, if you do not know if the > report is a bug or not, please do not ask the maintainers to determine it > for you. This is a good opportunity for you to look to see why your tool > reported an issue, and learn that subsystem. Look at if this is really a > bug or not, and investigate why. Appreciate your feedback. I'll be more careful in reporting things, and I think I need to make it more conservative... > The likely/unlikely tracing I do finds issues all over the kernel. But > before I report anything, I look at the subsystem and determine *why* it's > reporting what it does. In some cases, it's just a config issue. Where, I > may submit a patch saying "this is 100% wrong in X config, and we should > just remove the "unlikely". But I did the due diligence to find out exactly > what the issue is, and why the tooling reported what it reported. I'll try my best to do things that way. However, thing is that there's few reports with my system... That's why I shared Dept in LKML space. > I want to stress that your Dept tooling looks to have the potential of > being something that will be worth while including. But the false positives > needs to be down to the rate of lockdep false positives. As Ted said, if > it's reporting 95% false positives, nobody is going to look at the 5% of > real bugs that it finds. Agree. Dept should not be merged if so. I'm not pushing ahead, but I'm convinced that Dept works what a dependency tracker should do. Let's see how valuable it is esp. in the middle of developing something in the kernel. Thanks, Byungchul