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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A204BC004D4 for ; Sat, 21 Jan 2023 03:35:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229714AbjAUDf3 (ORCPT ); Fri, 20 Jan 2023 22:35:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48092 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229450AbjAUDf1 (ORCPT ); Fri, 20 Jan 2023 22:35:27 -0500 Received: from lgeamrelo11.lge.com (lgeamrelo13.lge.com [156.147.23.53]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id E331473EDC for ; Fri, 20 Jan 2023 19:35:25 -0800 (PST) Received: from unknown (HELO lgemrelse6q.lge.com) (156.147.1.121) by 156.147.23.53 with ESMTP; 21 Jan 2023 12:35:24 +0900 X-Original-SENDERIP: 156.147.1.121 X-Original-MAILFROM: byungchul.park@lge.com Received: from unknown (HELO localhost.localdomain) (10.177.244.38) by 156.147.1.121 with ESMTP; 21 Jan 2023 12:35:24 +0900 X-Original-SENDERIP: 10.177.244.38 X-Original-MAILFROM: byungchul.park@lge.com From: Byungchul Park To: hdanton@sina.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, torvalds@linux-foundation.org, longman@redhat.com, penguin-kernel@I-love.SAKURA.ne.jp, max.byungchul.park@gmail.com Subject: Re: [PATCH RFC v7 08/23] dept: Apply sdt_might_sleep_strong() to PG_{locked,writeback} wait Date: Sat, 21 Jan 2023 12:35:09 +0900 Message-Id: <1674272109-21876-1-git-send-email-byungchul.park@lge.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1674092314-16409-1-git-send-email-byungchul.park@lge.com> References: <1674092314-16409-1-git-send-email-byungchul.park@lge.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Byungchul wrote: > Hillf wrote: > > On 9 Jan 2023 12:33:36 +0900 Byungchul Park > > > Makes Dept able to track dependencies by PG_{locked,writeback} waits. > > > > > > Signed-off-by: Byungchul Park > > > --- > > > > Hey Byungchul > > +cc max.byungchul.park@gmail.com > > Hi, > > This email never reached to me. > > > Is DEPT able to get deadlock reported for the syzbot report [1]? > > DEPT can detect the case 100% *IF* the folio_trylock() is released > within the same context since DEPT tracks folio_trylock(), folio_lock() > and folio_unlock(), and it's definitely a deadlock. > > But as we know, because folio_trylock() can be released by another > context like irq, it might be either just a severe slowdown of the > context triggering folio_unlock() or a literal deadlock where the > context is involved. I dunno which one is the case. > > In short, DEPT can detect this case too *IF* it's a literal deadlock, > but it doesn't if it's just a slowdown. I'm planning to warn it even if > there is a slowdown tho, not for now. > > Let me reproduce the following issue. I will share the result. Hi Hillf, Can we talk about the DEPT report for the hang issue in here? https://lore.kernel.org/lkml/1673235231-30302-1-git-send-email-byungchul.park@lge.com/T/#m458f4d5f3da06a28c7fbb39b392d05e4c016603b Thanks, Byungchul > > Hillf > > > > [1] https://lore.kernel.org/lkml/6383cde5-cf4b-facf-6e07-1378a485657d@I-love.SAKURA.ne.jp/ > > Byungchul >