Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751354AbdHaIPM (ORCPT ); Thu, 31 Aug 2017 04:15:12 -0400 Received: from LGEAMRELO11.lge.com ([156.147.23.51]:50544 "EHLO lgeamrelo11.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750872AbdHaIPJ (ORCPT ); Thu, 31 Aug 2017 04:15:09 -0400 X-Original-SENDERIP: 156.147.1.125 X-Original-MAILFROM: byungchul.park@lge.com X-Original-SENDERIP: 10.177.222.33 X-Original-MAILFROM: byungchul.park@lge.com Date: Thu, 31 Aug 2017 17:15:01 +0900 From: Byungchul Park To: Peter Zijlstra Cc: mingo@kernel.org, tj@kernel.org, boqun.feng@gmail.com, david@fromorbit.com, johannes@sipsolutions.net, oleg@redhat.com, linux-kernel@vger.kernel.org, kernel-team@lge.com Subject: Re: [PATCH 4/4] lockdep: Fix workqueue crossrelease annotation Message-ID: <20170831081501.GJ3240@X58A-UD3R> References: <20170825011114.GA3858@X58A-UD3R> <20170829085939.ggmb6xiohw67micb@hirez.programming.kicks-ass.net> <20170830020953.GE3240@X58A-UD3R> <20170830074117.GG3240@X58A-UD3R> <20170830085333.GM32112@worktop.programming.kicks-ass.net> <004601d3216e$a3702030$ea506090$@lge.com> <20170830091223.xxnh3podtcumlabm@hirez.programming.kicks-ass.net> <004701d32171$ce57d4c0$6b077e40$@lge.com> <20170830112546.GH3240@X58A-UD3R> <20170831080442.5vdgoaijzmrc776x@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170831080442.5vdgoaijzmrc776x@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 873 Lines: 32 On Thu, Aug 31, 2017 at 10:04:42AM +0200, Peter Zijlstra wrote: > On Wed, Aug 30, 2017 at 08:25:46PM +0900, Byungchul Park wrote: > > > For example - I'm giving you the same example repeatedly: > > > > context X context Y > > --------- --------- > > wait_for_completion(C) > > acquire(A) > > process_one_work() > > acquire(B) > > work->fn() > > complete(C) > > > > Please check C->A and C->B. > > Is there a caller of procesS_one_work() that holds a lock? It's not important. Ok, check the following, instead: context X context Y --------- --------- wait_for_completion(C) acquire(A) release(A) process_one_work() acquire(B) release(B) work->fn() complete(C) We don't need to lose C->A and C->B dependencies unnecessarily.