[PATCH 2/6] reduce module image and resident size

From: Rusty Russell
Date: Thu Apr 24 2008 - 01:01:50 EST



Resulting reduction (x86-64, gcc 4.1.2) with my (special purpose, i.e.
much reduced) configurations:
- 16k kernel resident size
- 180k module resident size
- 10k module image size

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
---
include/linux/module.h | 2 +-
kernel/module.c | 3 ++-
2 files changed, 3 insertions(+), 2 deletions(-)

diff -u
--- linux-2.6.25-rc5/include/linux/module.h 2008-03-10 13:24:33.000000000
+0100
+++ 2.6.25-rc5-module-reduce-size/include/linux/module.h 2008-03-04
11:26:17.000000000 +0100
@@ -190,7 +190,7 @@ void *__symbol_get_gpl(const char *symbo
extern typeof(sym) sym; \
__CRC_SYMBOL(sym, sec) \
static const char __kstrtab_##sym[] \
- __attribute__((section("__ksymtab_strings"))) \
+ __attribute__((section("__ksymtab_strings"), aligned(1))) \
= MODULE_SYMBOL_PREFIX #sym; \
static const struct kernel_symbol __ksymtab_##sym \
__used \
--- linux-2.6.25-rc5/kernel/module.c 2008-03-10 13:24:35.000000000 +0100
+++ 2.6.25-rc5-module-reduce-size/kernel/module.c 2008-03-04
11:26:17.000000000 +0100
@@ -1815,8 +1815,9 @@ static struct module *load_module(void _
unwindex = find_sec(hdr, sechdrs, secstrings, ARCH_UNWIND_SECTION_NAME);
#endif

- /* Don't keep modinfo section */
+ /* Don't keep modinfo and version sections. */
sechdrs[infoindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
+ sechdrs[versindex].sh_flags &= ~(unsigned long)SHF_ALLOC;
#ifdef CONFIG_KALLSYMS
/* Keep symbol and string tables for decoding later. */
sechdrs[symindex].sh_flags |= SHF_ALLOC;



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