Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-qa0-f49.google.com ([209.85.216.49]:34767 "EHLO mail-qa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755512Ab3CERuA (ORCPT ); Tue, 5 Mar 2013 12:50:00 -0500 Date: Tue, 5 Mar 2013 09:49:54 -0800 From: Tejun Heo To: Jeff Layton Cc: "Myklebust, Trond" , Oleg Nesterov , Mandeep Singh Baines , Ming Lei , "J. Bruce Fields" , Linux Kernel Mailing List , "linux-nfs@vger.kernel.org" , "Rafael J. Wysocki" , Andrew Morton , Ingo Molnar Subject: Re: LOCKDEP: 3.9-rc1: mount.nfs/4272 still has locks held! Message-ID: <20130305174954.GG12795@htj.dyndns.org> References: <4FA345DA4F4AE44899BD2B03EEEC2FA9286AD113@sacexcmbx05-prd.hq.netapp.com> <20130304092310.1d21100c@tlielax.poochiereds.net> <20130304205307.GA13527@redhat.com> <4FA345DA4F4AE44899BD2B03EEEC2FA9286AEEB0@sacexcmbx05-prd.hq.netapp.com> <20130305082308.6607d4db@tlielax.poochiereds.net> <20130305174648.GF12795@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20130305174648.GF12795@htj.dyndns.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Tue, Mar 05, 2013 at 09:46:48AM -0800, Tejun Heo wrote: > So, I think this is why implementing freezer as a separate blocking > mechanism isn't such a good idea. We're effectively introducing a > completely new waiting state to a lot of unsuspecting paths which > generates a lot of risks and eventually extra complexity to work > around those. I think we really should update freezer to re-use the > blocking points we already have - the ones used for signal delivery > and ptracing. That way, other code paths don't have to worry about an > extra stop state and we can confine most complexities to freezer > proper. Also, consolidating those wait states means that we can solve the event-to-response latency problem for all three cases - signal, ptrace and freezer, rather than adding separate backing-out strategy for freezer. -- tejun