From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753842AbZKID1U (ORCPT ); Sun, 8 Nov 2009 22:27:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753752AbZKID1T (ORCPT ); Sun, 8 Nov 2009 22:27:19 -0500 Received: from out02.mta.xmission.com ([166.70.13.232]:33804 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753538AbZKID1L (ORCPT ); Sun, 8 Nov 2009 22:27:11 -0500 To: Arjan van de Ven Cc: Russell King , linux-kernel@vger.kernel.org, Leo Chen Subject: Re: [PATCH 22/23] sysctl arm: Remove binary sysctl support References: <1257682930-31401-22-git-send-email-ebiederm@xmission.com> <20091108123422.GA9145@flint.arm.linux.org.uk> <20091108164855.595ec70d@infradead.org> From: ebiederm@xmission.com (Eric W. Biederman) Date: Sun, 08 Nov 2009 19:27:07 -0800 In-Reply-To: <20091108164855.595ec70d@infradead.org> (Arjan van de Ven's message of "Sun\, 8 Nov 2009 16\:48\:55 -0800") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-XM-SPF: eid=;;;mid=;;;hst=in01.mta.xmission.com;;;ip=76.21.114.89;;;frm=ebiederm@xmission.com;;;spf=neutral X-SA-Exim-Connect-IP: 76.21.114.89 X-SA-Exim-Mail-From: ebiederm@xmission.com X-SA-Exim-Version: 4.2.1 (built Thu, 25 Oct 2007 00:26:12 +0000) X-SA-Exim-Scanned: No (on in01.mta.xmission.com); Unknown failure Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Arjan van de Ven writes: > On Sun, 08 Nov 2009 15:05:05 -0800 > ebiederm@xmission.com (Eric W. Biederman) wrote: > >> > >> > The practical difference is that /proc support now must be compiled >> > in to support sys_sysctl. >> >> But thanks for the reminder that I need to go into glibc and fix this >> before we disable the sys_sysctl emulation by default. > > how are you dealing with existing glibcs ? Or with static linked > binaries? or.. or .. > > breaking a heavily used ABI like this is not going to be pretty > or even sane, no matter which way you hate the current one. sysctl_binary.c has all of the code to continue to provide the existing ABI. sys_sysctl is not heavily used at all, and this is the responsible removal of a practically unused ABI. Last I check (and this was before I shouted to the world that sys_sysctl is going away) I could count on one hand all of the users of sys_sysctl. /proc/sys will definitely continue to exist. I just took a look and the use in linux threads that I don't warn about is used by glibc-2.8 but not by glibc-2.10. glibc-2.11 has just been released. so by next year when the removal is scheduled we are looking at multiple releases of glibc that don't use sys_sysctl. So I expect shortly I can warn about all uses of sys_sysctl without anyone seeing a warning. The one unfixed case I know about is fixing ioperm on arm, in the glibc ports tree, and that will need to happen before sys_sysctl is disabled by default. Which is all I intend to do when we reach that point in feature removal schedule now that I have refactored the code so that sys_sysctl no longer imposes a maintenance burden on the sane sysctl users. I don't hate sysctl, in fact for global tuneables I would argue for all it's faults sysctl it is one of the better interfaces we have. I just figure the implementation needs to be optimized for the way sysctl is used today, the via /proc/sys. Eric