From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932986AbaLDSCX (ORCPT ); Thu, 4 Dec 2014 13:02:23 -0500 Received: from e32.co.us.ibm.com ([32.97.110.150]:43446 "EHLO e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932382AbaLDSCU (ORCPT ); Thu, 4 Dec 2014 13:02:20 -0500 Date: Thu, 4 Dec 2014 10:02:10 -0800 From: "Paul E. McKenney" To: Pranith Kumar Cc: linux-kernel@vger.kernel.org, Josh Triplett Subject: Re: [RFC PATCH v2] tinification: Introduce CONFIG_SRCU to make SRCU optional Message-ID: <20141204180210.GS25340@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <1417665832-6933-1-git-send-email-bobby.prani@gmail.com> <20141204062704.GH25340@linux.vnet.ibm.com> <54807FC3.9050305@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54807FC3.9050305@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14120418-0005-0000-0000-000006DC5875 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 04, 2014 at 10:37:39AM -0500, Pranith Kumar wrote: > On 12/04/2014 01:27 AM, Paul E. McKenney wrote: > > For the moment, I applied this to -rcu against v3.18-rc6 to get some 0day > > testing on it. > > > > There are conflicts against the tip of my tree, but will worry about > > that later. I don't have a ready answer on whether or not this needs > > to be split up -- in the worst case, we would add the SRCU Kconfig > > parameter, add all the selects, then once they all hit mainline add the > > Makefile change. > > > > We will need stats on how much memory was saved, and a "size kernel/rcu/srcu.o" > > after a UP/tiny build should do it. Could you please add this to the > > commit log? > > > > So if we do not select CONFIG_SRCU, srcu.o will not be compiled at all. So we should save about > > text data bss dec hex filename > 2007 0 0 2007 7d7 kernel/rcu/srcu.o > > as in size of arch/powerpc/boot/zImage changes from > > text data bss dec hex filename > 831552 64180 23944 919676 e087c arch/powerpc/boot/zImage : before > 829504 64180 23952 917636 e0084 arch/powerpc/boot/zImage : after > > so about ~2000 bytes I guess. Nice! Josh, I recall you having a tinified .config somewhere, but don't see it right off. If you do have one, could you please share it with Pranith? Not a big deal, just don't want to overstate the savings too much. ;-) Thanx, Paul