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Message-Id: <200709122145.52026.vda.linux@googlemail.com>
Date: Wed, 12 Sep 2007 21:45:51 +0100
From: Denys Vlasenko <vda.linux@...glemail.com>
To: Sam Ravnborg <sam@...nborg.org>
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH 3/2] section garbage collection for i386 - BONUS TRACK
Hi Sam,
This patch makes i386 vmlinux linker script simpler
by minimizing number of generated sections.
For example, these sections:
21 .init.text 000204a0 78701000 00701000 00502000 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
22 .init.data 000268db 787214a0 007214a0 005224a0 2**3
CONTENTS, ALLOC, LOAD, DATA
23 .init.setup 00000654 78747d80 00747d80 00548d80 2**2
CONTENTS, ALLOC, LOAD, DATA
24 .initcall.init 000004c4 787483d4 007483d4 005493d4 2**2
CONTENTS, ALLOC, LOAD, DATA
25 .con_initcall.init 00000008 78748898 00748898 00549898 2**2
CONTENTS, ALLOC, LOAD, DATA
26 .altinstructions 00009c23 787488a0 007488a0 005498a0 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
27 .altinstr_replacement 000027de 787524c3 007524c3 005534c3 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
28 .exit.text 00000f31 78754ca4 00754ca4 00555ca4 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
29 .init.ramfs 00000086 78756000 00756000 00557000 2**0
CONTENTS, ALLOC, LOAD, READONLY, DATA
code, data, data, data, rodata, code, code, data... -
doesn't look clean.
Can more sanely be grouped like this:
15 .init.text 00023baf 78701000 00701000 00502000 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
16 .init.rodata 00009ca8 78725000 00725000 00526000 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
17 .init.data 00027408 7872eca8 0072eca8 0052fca8 2**3
CONTENTS, ALLOC, LOAD, DATA
All in all, we have 20 sections instead of 32, and it still boots okay.
Full listing:
Before:
$ objdump -h
linux-2.6.23-rc4.gc6.t/vmlinux: file format elf32-i386
Sections:
Idx Name Size VMA LMA File off Algn
0 .head.text 00000379 78200000 00200000 00001000 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
1 .text 003646da 78200380 00200380 00001380 2**4
CONTENTS, ALLOC, LOAD, READONLY, CODE
2 __ex_table 00000ee8 78564a60 00564a60 00365a60 2**3
CONTENTS, ALLOC, LOAD, READONLY, DATA
3 .notes 00000024 78565948 00565948 00366948 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
4 .rodata 000e85fe 78566000 00566000 00367000 2**3
CONTENTS, ALLOC, LOAD, READONLY, DATA
5 .pci_fixup 00000700 7864e600 0064e600 0044f600 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
6 __ksymtab 000057a0 7864ed00 0064ed00 0044fd00 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
7 __ksymtab_gpl 00001ac0 786544a0 006544a0 004554a0 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
8 __ksymtab_gpl_future 00000018 78655f60 00655f60 00456f60 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
9 __kcrctab 00002bd0 78655f78 00655f78 00456f78 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
10 __kcrctab_gpl 00000d60 78658b48 00658b48 00459b48 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
11 __kcrctab_gpl_future 0000000c 786598a8 006598a8 0045a8a8 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
12 __ksymtab_strings 00010d8b 786598b4 006598b4 0045a8b4 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
13 __param 00001838 7866a640 0066a640 0046b640 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
14 .data 0007fe99 7866c000 0066c000 0046d000 2**7
CONTENTS, ALLOC, LOAD, DATA
15 .data_nosave 00001000 786ec000 006ec000 004ed000 2**12
CONTENTS, ALLOC, LOAD, DATA
16 .page_aligned.data 00000800 786ed000 006ed000 004ee000 2**2
CONTENTS, ALLOC, LOAD, DATA
17 .cacheline_aligned.data 0000a000 786ed800 006ed800 004ee800 2**7
CONTENTS, ALLOC, LOAD, DATA
18 .read_mostly.data 000020d0 786f7800 006f7800 004f8800 2**7
CONTENTS, ALLOC, LOAD, DATA
19 .init_task.data 00002000 786fa000 006fa000 004fb000 2**2
CONTENTS, ALLOC, LOAD, DATA
20 .smp_locks 00004798 786fc000 006fc000 004fd000 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
21 .init.text 000204a0 78701000 00701000 00502000 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
22 .init.data 000268db 787214a0 007214a0 005224a0 2**3
CONTENTS, ALLOC, LOAD, DATA
23 .init.setup 00000654 78747d80 00747d80 00548d80 2**2
CONTENTS, ALLOC, LOAD, DATA
24 .initcall.init 000004c4 787483d4 007483d4 005493d4 2**2
CONTENTS, ALLOC, LOAD, DATA
25 .con_initcall.init 00000008 78748898 00748898 00549898 2**2
CONTENTS, ALLOC, LOAD, DATA
26 .altinstructions 00009c23 787488a0 007488a0 005498a0 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
27 .altinstr_replacement 000027de 787524c3 007524c3 005534c3 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
28 .exit.text 00000f31 78754ca4 00754ca4 00555ca4 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
29 .init.ramfs 00000086 78756000 00756000 00557000 2**0
CONTENTS, ALLOC, LOAD, READONLY, DATA
30 .percpu.data 00005f38 78757000 00757000 00558000 2**12
CONTENTS, ALLOC, LOAD, DATA
31 .bss 00047000 7875d000 0075d000 0055df38 2**12
ALLOC
32 .comment 00005004 00000000 00000000 0055df38 2**0
CONTENTS, READONLY
After:
linux-2.6.23-rc4.gc7.t/vmlinux: file format elf32-i386
Sections:
Idx Name Size VMA LMA File off Algn
0 .text 00364a5a 78200000 00200000 00001000 2**4
CONTENTS, ALLOC, LOAD, READONLY, CODE
1 __ex_table 00000ee8 78564a60 00564a60 00365a60 2**3
CONTENTS, ALLOC, LOAD, READONLY, DATA
2 .notes 00000024 78565948 00565948 00366948 2**2
CONTENTS, ALLOC, LOAD, READONLY, CODE
3 .rodata 000e8602 78566000 00566000 00367000 2**3
CONTENTS, ALLOC, LOAD, READONLY, DATA
4 .pci_fixup 00000700 7864e604 0064e604 0044f604 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
5 __ksymtab 000057a0 7864ed04 0064ed04 0044fd04 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
6 __ksymtab_gpl 00001ac0 786544a4 006544a4 004554a4 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
7 __ksymtab_gpl_future 00000018 78655f64 00655f64 00456f64 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
8 __kcrctab 00002bd0 78655f7c 00655f7c 00456f7c 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
9 __kcrctab_gpl 00000d60 78658b4c 00658b4c 00459b4c 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
10 __kcrctab_gpl_future 0000000c 786598ac 006598ac 0045a8ac 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
11 __ksymtab_strings 00010d8b 786598b8 006598b8 0045a8b8 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
12 __param 00001838 7866a644 0066a644 0046b644 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
13 .data 0008f7d0 7866c000 0066c000 0046d000 2**12
CONTENTS, ALLOC, LOAD, DATA
14 .smp_locks 00004798 786fc000 006fc000 004fd000 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
15 .init.text 00023baf 78701000 00701000 00502000 2**0
CONTENTS, ALLOC, LOAD, READONLY, CODE
16 .init.rodata 00009ca8 78725000 00725000 00526000 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
17 .init.data 00027408 7872eca8 0072eca8 0052fca8 2**3
CONTENTS, ALLOC, LOAD, DATA
18 .percpu.data 00005f38 78757000 00757000 00558000 2**12
CONTENTS, ALLOC, LOAD, DATA
19 .bss 00047000 7875d000 0075d000 0055df38 2**12
ALLOC
20 .comment 00005004 00000000 00000000 0055df38 2**0
CONTENTS, READONLY
Patch is run-tested.
It's purely cleanup work, it's not bringing any noticeable
size wins (well, maybe statistically it will have a bit less
alignment padding because I placed together a few page-aligned
chunks, but that's all).
Signed-off-by: Denys Vlasenko <vda.linux@...glemail.com>
--
vda
View attachment "linux-2.6.23-rc4.7.i386part2.patch" of type "text/x-diff" (6592 bytes)
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