Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752410AbbETFmR (ORCPT ); Wed, 20 May 2015 01:42:17 -0400 Received: from ozlabs.org ([103.22.144.67]:58132 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750920AbbETFmM (ORCPT ); Wed, 20 May 2015 01:42:12 -0400 From: Rusty Russell To: Joe Perches , One Thousand Gnomes Cc: David Woodhouse , LKML , Quentin Casasnovas , Michal Marek , Andreas Schwab Subject: Re: mod_devicetable: Make dmi_strmatch.substr const char * In-Reply-To: <1432063162.2870.199.camel@perches.com> References: <1431994055.2870.102.camel@perches.com> <1432018018.3277.22.camel@infradead.org> <20150519165630.169c64d3@lxorguk.ukuu.org.uk> <1432063162.2870.199.camel@perches.com> User-Agent: Notmuch/0.17 (http://notmuchmail.org) Emacs/24.4.1 (x86_64-pc-linux-gnu) Date: Wed, 20 May 2015 14:49:03 +0930 Message-ID: <878ucjhlmg.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3424 Lines: 92 Joe Perches writes: > On Tue, 2015-05-19 at 16:56 +0100, One Thousand Gnomes wrote: >> On Tue, 19 May 2015 07:46:58 +0100 David Woodhouse wrote: >> > On Mon, 2015-05-18 at 17:07 -0700, Joe Perches wrote: >> > > changed dmi_strmatch.substr from char * to char[79]; >> > > >> > > Changing it back to const char * would shrink an x86-64 >> > > defconfig more than 100KB. >> > > >> > > $ size vmlinux.old vmlinux.new >> > > text data bss dec hex filename >> > > 11941725 1825624 1085440 14852789 e2a2b5 vmlinux.old >> > > 11921172 1730648 1085440 14737260 e0df6c vmlinux.new >> >> What percentage of those are __initdata ? > > old: 17 .init.data 000876b0 ffffffff81f9e000 0000000001f9e000 0139e000 2**12 > new: 17 .init.data 000711b0 ffffffff81f9d000 0000000001f9d000 0139d000 2**12 > > .init.data: 0x876b0 - 0x711b0 = 0x16500 (91392) > vmlinux: 14852789 - 14737260 = 115529 > > so there's ~25KB delta that's not .init.data. > > The longest DMI_MATCH substr I found was 40 chars, so > there's some value in reducing the substr size of 79 > to something shorter like 47 to reduce 80*4=320 to > 48*4=192 per use. This patch is nice and trivial. But it seems the file2alias code was rewritten in 2013 by Andreas Schwab , and SOB Michal Marek , without going through me. Annoying, since they had to hack it because people screwed up mod_devicetable.h with arch-dependent layouts :( I guess that means Michal is the maintainer now, so I've CC'd him. Cheers, Rusty. > $ grep-2.5.4 -rP --include=*.[ch] "\bDMI_(?:EXACT_)?MATCH\s*\(\s*\w+\s*,\s*\"[^\"]*" *| \ > grep -oh '"[^"]*"' | \ > sed 's/"//g' | sort | uniq | \ > awk '{print length($0), " ", $0}'| \ > sort -rn | head -10 > 39 Matsushita Electric Industrial Co.,Ltd. > 35 ASUS PR-DLS ACPI BIOS Revision 1010 > 34 Micro-Star International Co., Ltd. > 34 Award Software International, Inc. > 34 900X3C/900X3D/900X3E/900X4C/900X4D > 34 370R4E/370R4V/370R5E/3570RE/370R5V > 33 MICRO-STAR INTERNATIONAL CO., LTD > 32 MV85010A.86A.0016.P07.0201251536 > 32 MO81010A.86A.0008.P04.0004170800 > 32 ASUS A7V ACPI BIOS Revision 1007 > > Changing substr from 79 to 47 reduces .init.data a bit > (different -next version) > > old: 17 .init.data 00081718 ffffffff81f84000 0000000001f84000 01384000 2**12 > new: 17 .init.data 00076598 ffffffff81f84000 0000000001f84000 01384000 2**12 > > .init.data: 0x81718 - 0x76598 = 0xb180 (45440) > > Unless/until modpost is updated, maybe this patch is OK: > --- > include/linux/mod_devicetable.h | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h > index 3bfd567..279f1be 100644 > --- a/include/linux/mod_devicetable.h > +++ b/include/linux/mod_devicetable.h > @@ -462,7 +462,11 @@ enum dmi_field { > struct dmi_strmatch { > unsigned char slot:7; > unsigned char exact_match:1; > - char substr[79]; > +#ifdef CONFIG_MODULES > + char substr[47]; > +#else > + const char *substr; > +#endif > }; > > struct dmi_system_id { -- 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/