Joe Perches <j...@perches.com> 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 <dw...@infradead.org>
>> 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
<sch...@linux-m68k.org>, and SOB Michal Marek <mma...@suse.cz>, 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 {
--
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