From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754549Ab2JEItj (ORCPT ); Fri, 5 Oct 2012 04:49:39 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:49373 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754494Ab2JEItg (ORCPT ); Fri, 5 Oct 2012 04:49:36 -0400 Date: Fri, 5 Oct 2012 01:50:36 -0700 From: Andrew Morton To: Greg KH Cc: Geert Uytterhoeven , Ralf Baechle , Bjorn Helgaas , Chris Metcalf , Chris Zankel , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Tim Bird Subject: Re: [patch 0/3] Turn CONFIG_HOTPLUG always on. Message-Id: <20121005015036.0d0b7ebd.akpm@linux-foundation.org> In-Reply-To: <20120906202815.GA6732@kroah.com> References: <20120904234803.554552301@clark.kroah.org> <20120906202815.GA6732@kroah.com> X-Mailer: Sylpheed 2.7.1 (GTK+ 2.18.9; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 6 Sep 2012 13:28:16 -0700 Greg KH wrote: > On Tue, Sep 04, 2012 at 05:01:05PM -0700, Greg Kroah-Hartman wrote: > > From: Greg KH > > > > The CONFIG_HOTPLUG variable is tough to turn off, and almost all arches > > default to it on. > > > > If you turn it off, it saves you a big 200 or so bytes, and then starts > > to cause all sorts of problems as the code paths if the option is > > disabled is never really tested, and memory segments start to get thrown > > away that driver authors assume will always be present. > > > > So, as part of trying to get rid of the option entirely, let's just turn > > the option always on. > > > > Note, to do this properly, I found two duplicate definitions of the > > option, in the Tile and Xtensa arch files, this patch series removes > > those duplicates first. > > > > Anyone object to me just taking these three patches through my > > driver-core tree for 3.7? After this set, I'll start unwinding the > > places where CONFIG_HOTPLUG is used and remove the parts that are not > > used anymore now that the option can not be turned off. > > Given the lack of objection, I've now queued these up for 3.7 and will > start unwinding the CONFIG_HOTPLUG mess. > I wonder if this has had sufficient consideration. It isn't just 200 bytes, is it? It's all memory which is marked __devinit* and __devexit* - that's a tremendous amount of stuff. We should quantify it. It wouldn't surprise me if there are organizations who are using CONFIG_HOTPLUG=n effectively. We regularly bust a gut to save a few bytes and for people who really care about this we're here sending them backwards a lot further than that. Tim, do you know?