Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752351Ab3ECERY (ORCPT ); Fri, 3 May 2013 00:17:24 -0400 Received: from mail-vb0-f49.google.com ([209.85.212.49]:39672 "EHLO mail-vb0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751189Ab3ECERW (ORCPT ); Fri, 3 May 2013 00:17:22 -0400 MIME-Version: 1.0 In-Reply-To: <20130503040934.GA16968@mtj.dyndns.org> References: <1367458508-9133-1-git-send-email-ccross@android.com> <1367458508-9133-4-git-send-email-ccross@android.com> <20130502235505.GW19814@mtj.dyndns.org> <20130503000358.GX19814@mtj.dyndns.org> <20130503040934.GA16968@mtj.dyndns.org> Date: Thu, 2 May 2013 21:17:21 -0700 X-Google-Sender-Auth: KnMoyHNqvhmI4hSeFuijh2vP1h8 Message-ID: Subject: Re: [PATCH v2 03/10] freezer: add new freezable helpers using freezer_do_not_count() From: Colin Cross To: Tejun Heo Cc: Linux PM list , lkml , "Rafael J. Wysocki" , =?ISO-8859-1?Q?Arve_Hj=F8nnev=E5g?= , Oleg Nesterov , Len Brown , Pavel Machek , Jeff Layton , Mandeep Baines Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1809 Lines: 37 On Thu, May 2, 2013 at 9:09 PM, Tejun Heo wrote: > Hello, > > On Thu, May 02, 2013 at 07:41:39PM -0700, Colin Cross wrote: >> On Thu, May 2, 2013 at 7:16 PM, Colin Cross wrote: >> > This sounds the same as what ended up getting reverted in >> > https://lkml.org/lkml/2013/3/4/221 >> > I can add the WARN_ON_ONCE to all my new calls, and leave them out of >> > existing calls, but that seems a little odd, and will be redundant if >> > the lockdep call in try_to_freeze goes back in in 3.11. Do you still >> > want it in the new apis? > ... >> I could also put the lockdep check that was reveted back into >> try_to_freeze(), and add a freezable_schedule_unsafe() that skips it >> for use in the known-unsafe users in nfs, with a big comment not to >> add new users of it. > > Oh yeah, that sounds like a good idea, and as for the non-ugly > variants, at least in the mid/long term, I think it'd be best to add > the lockdep annotation to try_to_freeze() with > __try_to_freeze_unsafe_youre_gonna_burn_in_hell_if_you_use_this() for > the existing users which should be gradually converted, but if that's > too burdensome, adding warnings to the wrappers should do for now, I > guess. > > And I *hope* the lockdep annotation is stricter than what was added > before. I think it better be "no lock ever should be held at this > point" rather than "consider this a big lock". The previous patch (6aa9707099c4b25700940eb3d016f16c4434360d in Linus' tree) already required that no locks be held, it wasn't using a lock annotation. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/