From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id 100A06B025E for ; Wed, 18 Jan 2017 01:42:07 -0500 (EST) Received: by mail-pf0-f197.google.com with SMTP id f144so6362741pfa.3 for ; Tue, 17 Jan 2017 22:42:07 -0800 (PST) Received: from mail-pf0-x241.google.com (mail-pf0-x241.google.com. [2607:f8b0:400e:c00::241]) by mx.google.com with ESMTPS id o184si9544910pfb.214.2017.01.17.22.42.06 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 17 Jan 2017 22:42:06 -0800 (PST) Received: by mail-pf0-x241.google.com with SMTP id 19so448399pfo.3 for ; Tue, 17 Jan 2017 22:42:06 -0800 (PST) Date: Wed, 18 Jan 2017 14:42:30 +0800 From: Boqun Feng Subject: Re: [PATCH v4 15/15] lockdep: Crossrelease feature documentation Message-ID: <20170118064230.GF15084@tardis.cn.ibm.com> References: <1481260331-360-1-git-send-email-byungchul.park@lge.com> <1481260331-360-16-git-send-email-byungchul.park@lge.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="qM81t570OJUP5TU/" Content-Disposition: inline In-Reply-To: <1481260331-360-16-git-send-email-byungchul.park@lge.com> Sender: owner-linux-mm@kvack.org List-ID: To: Byungchul Park Cc: peterz@infradead.org, mingo@kernel.org, tglx@linutronix.de, walken@google.com, kirill@shutemov.name, linux-kernel@vger.kernel.org, linux-mm@kvack.org, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, npiggin@gmail.com --qM81t570OJUP5TU/ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Dec 09, 2016 at 02:12:11PM +0900, Byungchul Park wrote: [...] > +Example 1: > + > + CONTEXT X CONTEXT Y > + --------- --------- > + mutext_lock A > + lock_page B > + lock_page B > + mutext_lock A /* DEADLOCK */ s/mutext_lock/mutex_lock > + unlock_page B > + mutext_unlock A > + mutex_unlock A > + unlock_page B > + > + where A is a lock class and B is a page lock. > + > +No, we cannot. > + > +Example 2: > + > + CONTEXT X CONTEXT Y CONTEXT Z > + --------- --------- ---------- > + mutex_lock A > + lock_page B > + lock_page B > + mutext_lock A /* DEADLOCK */ > + mutext_unlock A Ditto. > + unlock_page B held by X > + unlock_page B > + mutex_unlock A > + > + where A is a lock class and B is a page lock. > + > +No, we cannot. > + > +Example 3: > + > + CONTEXT X CONTEXT Y > + --------- --------- > + mutex_lock A > + mutex_lock A > + mutex_unlock A > + wait_for_complete B /* DEADLOCK */ I think this part better be: CONTEXT X CONTEXT Y --------- --------- mutex_lock A mutex_lock A wait_for_complete B /* DEADLOCK */ mutex_unlock A , right? Because Y triggers DEADLOCK before X could run mutex_unlock(). Regards, Boqun --qM81t570OJUP5TU/ Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEEj5IosQTPz8XU1wRHSXnow7UH+rgFAlh/DlIACgkQSXnow7UH +rgQQwf9E19qbmMxZXyNiuBhO/JQ4KtJrJLK/UTgqJHEOX5XoiJsoETe5tisBFPR YMyMkcycnEDtfPjluXA1wsl5ye9egPSkMlPXocddw99Pg4k4BfAUrA6OD82ckRHj oBulA9dfeeZ17eXwZvF69BLqa6k+T9OS5VC+X/J5DznP415EhSH0nZVDgXUtpS1t YpQaoK6Z0CzqFQrkyVgJHpI5efhRBraaBMEGOg+rqVVAo3SbmKcq2wwvyuxj3yeX 0Ldj7hXx9L+/KgZjRXRoMj3goMFF251NIAbiqzOPpSljTwL6YgYoPmR4dUCr8lNo OgPKIyfOhTDMEFyeYpF4MilrD9WJvg== =1Eus -----END PGP SIGNATURE----- --qM81t570OJUP5TU/-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org