From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756111Ab2JEOcw (ORCPT ); Fri, 5 Oct 2012 10:32:52 -0400 Received: from mail-pa0-f46.google.com ([209.85.220.46]:36437 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756073Ab2JEOcu (ORCPT ); Fri, 5 Oct 2012 10:32:50 -0400 Date: Fri, 5 Oct 2012 07:32:46 -0700 From: Greg KH To: Andrew Morton 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: <20121005143246.GA18276@kroah.com> References: <20120904234803.554552301@clark.kroah.org> <20120906202815.GA6732@kroah.com> <20121005015036.0d0b7ebd.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20121005015036.0d0b7ebd.akpm@linux-foundation.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 05, 2012 at 01:50:36AM -0700, Andrew Morton wrote: > 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. Given the recent round of patches that I've applied to the tree making it so that CONFIG_HOTPLUG=n actually boots and works, that were needed for the past 6+ kernel versions, I find it very unlikely anyone actually runs a system in this type of configuration, but I would love to hear from someone who does if they are out there. greg k-h