From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753379AbYBQT2m (ORCPT ); Sun, 17 Feb 2008 14:28:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751347AbYBQT2e (ORCPT ); Sun, 17 Feb 2008 14:28:34 -0500 Received: from pasmtpb.tele.dk ([80.160.77.98]:47671 "EHLO pasmtpB.tele.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751278AbYBQT2d (ORCPT ); Sun, 17 Feb 2008 14:28:33 -0500 Date: Sun, 17 Feb 2008 20:28:40 +0100 From: Sam Ravnborg To: Ian Campbell Cc: Matt Mackall , Linux Mailing List , Ingo Molnar , "Huang, Ying" Subject: Re: arch/x86/mm/ioremap unification grew by 10x Message-ID: <20080217192840.GH14588@uranus.ravnborg.org> References: <1203107155.12383.230.camel@cinder.waste.org> <20080215203228.GA4295@uranus.ravnborg.org> <1203110488.12383.231.camel@cinder.waste.org> <1203117425.12383.238.camel@cinder.waste.org> <1203275382.27987.20.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1203275382.27987.20.camel@localhost.localdomain> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Feb 17, 2008 at 07:09:42PM +0000, Ian Campbell wrote: > > On Fri, 2008-02-15 at 17:17 -0600, Matt Mackall wrote: > > On Fri, 2008-02-15 at 15:21 -0600, Matt Mackall wrote: > > > On Fri, 2008-02-15 at 21:32 +0100, Sam Ravnborg wrote: > > > > On Fri, Feb 15, 2008 at 02:25:54PM -0600, Matt Mackall wrote: > > > > > In 2.6.24 defconfig, my build stats show ioremap_32.o was 1.8k. In > > > > > 2.6.25-rc1, the unified ioremap.o is 20.8k. > > > > > > > > Just an observation - 17 commits touches said file after > > > > the unification (at least in latest -linus). > > > > > > Correction: those numbers should be halved. So we're going from .9k to > > > 10.4k. > > > > And here's most of the cause: > > > > 000002b8 00000124 T early_ioremap > > 00001000 00001000 t bm_pte > > 00002000 00000004 T early_ioremap_debug > > > > static __initdata pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] > > __attribute__((aligned(PAGE_SIZE))); > > > > Double ouch. First, this isn't in BSS. Second, even though it's > > initdata, the alignment slop won't get recovered. > > 551889a6e2a24a9c06fd453ea03b57b7746ffdc0 (the reason you CC'd me) only > changed this from unsigned long[1024] to pte_t[PAGE_SIZE/sizeof(pte_t)] > > -static __initdata unsigned long bm_pte[1024] > +static __initdata pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] > __attribute__((aligned(PAGE_SIZE))); > > I don't think that would have changed anything in this respect. It seems > to have been that way since 0947b2f31ca1ea1211d3cde2dbd8fcec579ef395 > when it was added (Huang Ying CC'd). > > > Don't we have a special section for page-aligned crap so it doesn't > > waste most of two pages? > > We have .bss.page_aligned and it seems appropriate to use it. > > Ian. > > --- > From ac954372c1ed7830148bdea1e4283856c05c354f Mon Sep 17 00:00:00 2001 > From: Ian Campbell > Date: Sun, 17 Feb 2008 19:08:34 +0000 > Subject: [PATCH] x86: bm_pte can be placed in .bss.page_aligned. > > text data bss dec hex filename > - 3388 8236 4 11628 2d6c ../build-32/arch/x86/mm/ioremap.o > + 3388 48 4100 7536 1d70 ../build-32/arch/x86/mm/ioremap.o > > Signed-off-by: Ian Campbell > Cc: Matt Mackall > Cc: Sam Ravnborg > Cc: Ingo Molnar > Cc: Huang Ying > --- > arch/x86/mm/ioremap.c | 4 ++-- > 1 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c > index 69f4981..c62ecbd 100644 > --- a/arch/x86/mm/ioremap.c > +++ b/arch/x86/mm/ioremap.c > @@ -262,8 +262,8 @@ static int __init early_ioremap_debug_setup(char *str) > early_param("early_ioremap_debug", early_ioremap_debug_setup); > > static __initdata int after_paging_init; > -static __initdata pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] > - __attribute__((aligned(PAGE_SIZE))); > +static pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] Replace > + __attribute__((__section__(".bss.page_aligned"))); with the shorter form: > + __section(.bss.page_aligned))); Sam