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author | Jiang Liu <liuj97@gmail.com> | 2013-07-04 00:03:33 +0200 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-07-04 01:07:34 +0200 |
commit | 1622d1abdf7b554eb7cc40c0d08d989176732242 (patch) | |
tree | d0553ae064f5ef452c1b34a1ef112279791d8bce /include | |
parent | mm: fix the TLB range flushed when __tlb_remove_page() runs out of slots (diff) | |
download | linux-1622d1abdf7b554eb7cc40c0d08d989176732242.tar.xz linux-1622d1abdf7b554eb7cc40c0d08d989176732242.zip |
vmlinux.lds: add comments for global variables and clean up useless declarations
The original goal of this patchset is to fix the bug reported by
https://bugzilla.kernel.org/show_bug.cgi?id=53501 Now it has also been
expanded to reduce common code used by memory initializion.
Patch 1-7:
1) add comments for global variables exported by vmlinux.lds
2) normalize global variables exported by vmlinux.lds
Patch 8:
Introduce helper functions mem_init_print_info() and
get_num_physpages()
Patch 9:
Avoid using global variable num_physpages at runtime
Patch 10:
Don't update num_physpages in memory_hotplug.c
Patch 11-40:
Modify arch mm initialization code to:
1) Simplify mem_init() by using mem_init_print_info()
2) Prepare for killing global variable num_physpages
Patch 41:
Kill the global variable num_physpages
With all patches applied, mem_init(), free_initmem(), free_initrd_mem()
could be as simple as below. This patch series has reduced about 1.2K
lines of code in total.
#ifndef CONFIG_DISCONTIGMEM
void __init
mem_init(void)
{
max_mapnr = max_low_pfn;
free_all_bootmem();
high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
mem_init_print_info(NULL);
}
#endif /* CONFIG_DISCONTIGMEM */
void
free_initmem(void)
{
free_initmem_default(-1);
}
#ifdef CONFIG_BLK_DEV_INITRD
void
free_initrd_mem(unsigned long start, unsigned long end)
{
free_reserved_area(start, end, -1, "initrd");
}
#endif
Due to hardware resource limitations, I have only tested this on x86_64.
And the messages reported on an x86_64 system are:
Log message before applying patches:
Memory: 7745676k/8910848k available (6934k kernel code, 836024k absent, 329148k reserved, 6343k data, 1012k init)
Log message after applying patches:
Memory: 7744624K/8074824K available (6969K kernel code, 1011K data, 2828K rodata, 1016K init, 9640K bss, 330200K reserved)
Great thanks to Vineet Gupta for testing on ARC.
This patch:
Document global variables exported from vmlinux.lds.
1) Add comments about usage guidelines for global variables exported
from vmlinux.lds.S.
2) Remove unused __initdata_begin[] and __initdata_end[].
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r-- | include/asm-generic/sections.h | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h index c1a1216e29ce..f1a24b5c3b90 100644 --- a/include/asm-generic/sections.h +++ b/include/asm-generic/sections.h @@ -3,6 +3,26 @@ /* References to section boundaries */ +/* + * Usage guidelines: + * _text, _data: architecture specific, don't use them in arch-independent code + * [_stext, _etext]: contains .text.* sections, may also contain .rodata.* + * and/or .init.* sections + * [_sdata, _edata]: contains .data.* sections, may also contain .rodata.* + * and/or .init.* sections. + * [__start_rodata, __end_rodata]: contains .rodata.* sections + * [__init_begin, __init_end]: contains .init.* sections, but .init.text.* + * may be out of this range on some architectures. + * [_sinittext, _einittext]: contains .init.text.* sections + * [__bss_start, __bss_stop]: contains BSS sections + * + * Following global variables are optional and may be unavailable on some + * architectures and/or kernel configurations. + * _text, _data + * __kprobes_text_start, __kprobes_text_end + * __entry_text_start, __entry_text_end + * __ctors_start, __ctors_end + */ extern char _text[], _stext[], _etext[]; extern char _data[], _sdata[], _edata[]; extern char __bss_start[], __bss_stop[]; @@ -12,7 +32,6 @@ extern char _end[]; extern char __per_cpu_load[], __per_cpu_start[], __per_cpu_end[]; extern char __kprobes_text_start[], __kprobes_text_end[]; extern char __entry_text_start[], __entry_text_end[]; -extern char __initdata_begin[], __initdata_end[]; extern char __start_rodata[], __end_rodata[]; /* Start and end of .ctors section - used for constructor calls. */ |