From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757979AbcIMKFc (ORCPT ); Tue, 13 Sep 2016 06:05:32 -0400 Received: from merlin.infradead.org ([205.233.59.134]:44904 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756409AbcIMKFa (ORCPT ); Tue, 13 Sep 2016 06:05:30 -0400 Date: Tue, 13 Sep 2016 12:05:20 +0200 From: Peter Zijlstra To: Byungchul Park Cc: mingo@kernel.org, tglx@linutronix.de, walken@google.com, boqun.feng@gmail.com, kirill@shutemov.name, linux-kernel@vger.kernel.org, linux-mm@kvack.org, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, npiggin@gmail.com Subject: Re: [PATCH v3 07/15] lockdep: Implement crossrelease feature Message-ID: <20160913100520.GA5035@twins.programming.kicks-ass.net> References: <1473759914-17003-1-git-send-email-byungchul.park@lge.com> <1473759914-17003-8-git-send-email-byungchul.park@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1473759914-17003-8-git-send-email-byungchul.park@lge.com> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 13, 2016 at 06:45:06PM +0900, Byungchul Park wrote: > Crossrelease feature calls a lock 'crosslock' if it is releasable > in any context. For crosslock, all locks having been held in the > release context of the crosslock, until eventually the crosslock > will be released, have dependency with the crosslock. > > Using crossrelease feature, we can detect deadlock possibility even > for lock_page(), wait_for_complete() and so on. > Completely inadequate. Please explain how cross-release does what it does. Talk about lock graphs and such. I do not have time to reverse engineer this stuff.