From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932392AbdHVJWq (ORCPT ); Tue, 22 Aug 2017 05:22:46 -0400 Received: from LGEAMRELO13.lge.com ([156.147.23.53]:50631 "EHLO lgeamrelo13.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932273AbdHVJWp (ORCPT ); Tue, 22 Aug 2017 05:22:45 -0400 X-Original-SENDERIP: 156.147.1.151 X-Original-MAILFROM: byungchul.park@lge.com X-Original-SENDERIP: 10.177.222.33 X-Original-MAILFROM: byungchul.park@lge.com Date: Tue, 22 Aug 2017 18:22:36 +0900 From: Byungchul Park To: Peter Zijlstra Cc: Dave Chinner , mingo@kernel.org, linux-kernel@vger.kernel.org, kernel-team@lge.com, Arnaldo Carvalho de Melo , Tejun Heo , Boqun Feng Subject: Re: [PATCH v3 1/3] lockdep: Make LOCKDEP_CROSSRELEASE configs all part of PROVE_LOCKING Message-ID: <20170822092236.GI20323@X58A-UD3R> References: <1502960261-16206-1-git-send-email-byungchul.park@lge.com> <20170821154600.asyzqs2zg6w6o4pg@hirez.programming.kicks-ass.net> <20170822054603.GT10621@dastard> <20170822090603.vufl5ncoequ5ag6x@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170822090603.vufl5ncoequ5ag6x@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 On Tue, Aug 22, 2017 at 11:06:03AM +0200, Peter Zijlstra wrote: > So I did the below little hack, which basically wipes the entire lock > history when we start a work and thereby disregards/looses the > dependency on the work 'lock'. > > It makes my test box able to boot and build a kernel on XFS, so while I > see what you're saying (I think), it doesn't appear to instantly show. > > Should I run xfstests or something to further verify things are OK? Does > that need a scratch partition (I keep forgetting how to run that stuff > :/). > > --- > diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c > index 66011c9f5df3..de91cdce9460 100644 > --- a/kernel/locking/lockdep.c > +++ b/kernel/locking/lockdep.c > @@ -4756,10 +4756,14 @@ void crossrelease_hist_start(enum xhlock_context_t c) > { > struct task_struct *cur = current; > > - if (cur->xhlocks) { > - cur->xhlock_idx_hist[c] = cur->xhlock_idx; > - cur->hist_id_save[c] = cur->hist_id; > - } > + if (!cur->xhlocks) > + return; > + > + if (c == XHLOCK_PROC) > + invalidate_xhlock(&xhlock(cur->xhlock_idx)); We have to detect dependecies if it exists, even in the following case: oooooooiiiiiiiiiiiiiiiiiii......... |<- range for commit ->| where o: acquisition outside of each work, i: acquisition inside of each work, With yours, we can never detect dependecies wrt 'o'. We have to remove false dependencies if we established them incorrectly. I will also think it more.