Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757327Ab0FOCwO (ORCPT ); Mon, 14 Jun 2010 22:52:14 -0400 Received: from mail-gy0-f174.google.com ([209.85.160.174]:45778 "EHLO mail-gy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754182Ab0FOCwM (ORCPT ); Mon, 14 Jun 2010 22:52:12 -0400 Date: Mon, 14 Jun 2010 22:52:08 -0400 (EDT) From: Tim Abbott X-X-Sender: tabbott@dr-wily.mit.edu To: James Bottomley cc: Matt Fleming , linux-arch@vger.kernel.org, Arnd Bergmann , linux-kernel@vger.kernel.org, Sam Ravnborg , Michal Marek , Denys Vlasenko , linux-parisc@vger.kernel.org Subject: Re: [PATCH 1/5] vmlinux.lds.h: Include *(.text.*) in TEXT_TEXT In-Reply-To: <1276557299.5374.847.camel@mulgrave.site> Message-ID: References: <1276519112-11649-1-git-send-email-matt@console-pimps.org> <87y6ehxvby.fsf@linux-g6p1.site> <1276557299.5374.847.camel@mulgrave.site> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2975 Lines: 72 On Mon, 14 Jun 2010, James Bottomley wrote: > On Mon, 2010-06-14 at 18:21 -0400, Tim Abbott wrote: > > On Mon, 14 Jun 2010, Matt Fleming wrote: > > > > > Do these special kernel sections include things like the parisc > > > .text.do_softirq, .text.sys_exit, etc? James raised a good objection to > > > the parisc patch of this series. I'm guessing most people saw it already > > > but I'll paste it here for reference, > > > > > > This would destroy all of the named parisc text ordering we do above the > > > removed line because now you'd have swept up all the function sections > > > before we get to them, won't it? > > > > > > The ordering is an execution speed up on 32 bit systems because our > > > relative jump is so short. > > > > > > Will you changes handle this OK? > > > > I think I addressed this in my reply to James just now, but to be super > > clear, this -ffunction-sections plan involves renaming .text.do_softirq to > > .text..do_softirq (etc.) first. > > OK, so that doesn't make a lot of sense to me; I suspect because you > don't understand what parisc is doing. These aren't names of linux > special sections ... they're names of function sections. For > efficiency, we take specific hot functions and place them together in > the linker script so the jumps between them are small enough to be coded > as relative on the 32 bit architecture. It's really just a more > efficient way of laying out the binary. Yeah, I'd forgotten parisc was doing -ffunction-sections, now I understand what you're talking about. What I'd recommend is just moving the .text.do_softirq and friends like in the hunk below -- I believe that should achieve the same performance goals, and should have no conflict with adding a wildcard for -ffunction-sections generated sections to TEXT_TEXT. -Tim Abbott diff --git a/arch/parisc/kernel/vmlinux.lds.S b/arch/parisc/kernel/vmlinux.lds.S index d64a6bb..ad0d3d3 100644 --- a/arch/parisc/kernel/vmlinux.lds.S +++ b/arch/parisc/kernel/vmlinux.lds.S @@ -52,15 +52,15 @@ SECTIONS _text = .; /* Text and read-only data */ .text ALIGN(16) : { HEAD_TEXT + *(.text.do_softirq) + *(.text.sys_exit) + *(.text.do_sigaltstack) + *(.text.do_fork) TEXT_TEXT SCHED_TEXT LOCK_TEXT KPROBES_TEXT IRQENTRY_TEXT - *(.text.do_softirq) - *(.text.sys_exit) - *(.text.do_sigaltstack) - *(.text.do_fork) *(.text.*) *(.fixup) *(.lock.text) /* out-of-line lock text */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/