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 46909C433EF for ; Mon, 23 May 2022 01:12:43 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 794046B0005; Sun, 22 May 2022 21:12:42 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 71D346B0006; Sun, 22 May 2022 21:12:42 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5E4A56B0007; Sun, 22 May 2022 21:12:42 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 4E6786B0005 for ; Sun, 22 May 2022 21:12:42 -0400 (EDT) Received: from smtpin31.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 196AEBD1 for ; Mon, 23 May 2022 01:12:42 +0000 (UTC) X-FDA: 79495232964.31.F29C850 Received: from lgeamrelo11.lge.com (lgeamrelo12.lge.com [156.147.23.52]) by imf25.hostedemail.com (Postfix) with ESMTP id 42D03A000F for ; Mon, 23 May 2022 01:12:11 +0000 (UTC) Received: from unknown (HELO lgeamrelo01.lge.com) (156.147.1.125) by 156.147.23.52 with ESMTP; 23 May 2022 10:12:36 +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; 23 May 2022 10:12:36 +0900 X-Original-SENDERIP: 10.177.244.38 X-Original-MAILFROM: byungchul.park@lge.com Date: Mon, 23 May 2022 10:10:45 +0900 From: Byungchul Park To: Theodore Ts'o Cc: tj@kernel.org, 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, rostedt@goodmis.org, joel@joelfernandes.org, sashal@kernel.org, daniel.vetter@ffwll.ch, chris@chris-wilson.co.uk, duyuyang@gmail.com, johannes.berg@intel.com, willy@infradead.org, david@fromorbit.com, amir73il@gmail.com, 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, 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, rodrigosiqueiramelo@gmail.com, melissa.srw@gmail.com, hamohammed.sa@gmail.com, 42.hyeyoo@gmail.com, mcgrof@kernel.org, holt@sgi.com Subject: Re: [REPORT] syscall reboot + umh + firmware fallback Message-ID: <20220523011045.GA16721@X58A-UD3R> References: <1652354304-17492-1-git-send-email-byungchul.park@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 42D03A000F X-Rspam-User: Authentication-Results: imf25.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf25.hostedemail.com: domain of byungchul.park@lge.com designates 156.147.23.52 as permitted sender) smtp.mailfrom=byungchul.park@lge.com X-Stat-Signature: 6zym34be4x8x3r7kro7uayhpmzei6esz X-HE-Tag: 1653268331-137543 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, May 12, 2022 at 09:56:46AM -0400, Theodore Ts'o wrote: > On Thu, May 12, 2022 at 08:18:24PM +0900, Byungchul Park wrote: > > I have a question about this one. Yes, it would never been stuck thanks > > to timeout. However, IIUC, timeouts are not supposed to expire in normal > > cases. So I thought a timeout expiration means not a normal case so need > > to inform it in terms of dependency so as to prevent further expiraton. > > That's why I have been trying to track even timeout'ed APIs. > > As I beleive I've already pointed out to you previously in ext4 and > ocfs2, the jbd2 timeout every five seconds happens **all** the time > while the file system is mounted. Commits more frequently than five > seconds is the exception case, at least for desktops/laptop workloads. Thanks, Ted. It's easy to stop tracking APIs with timeout. I've been just afraid that the cases that we want to suppress anyway will be skipped. However, I should stop it if it produces too many false alarms. > We *don't* get to the timeout only when a userspace process calls > fsync(2), or if the journal was incorrectly sized by the system > administrator so that it's too small, and the workload has so many > file system mutations that we have to prematurely close the > transaction ahead of the 5 second timeout. Yeah... It's how journaling works. Thanks. > > Do you think DEPT shouldn't track timeout APIs? If I was wrong, I > > shouldn't track the timeout APIs any more. > > DEPT tracking timeouts will cause false positives in at least some > cases. At the very least, there needs to be an easy way to suppress > these false positives on a per wait/mutex/spinlock basis. The easy way is to stop tracking those that are along with timeout until DEPT starts to consider waits/events by timeout functionality itself. Thanks. Byungchul > > - Ted