Subject: [merged] vmlinuxlds-add-comments-for-global-variables-and-clean-up-useless-declarations.patch removed from -mm tree
To: liuj97@xxxxxxxxx,arnd@xxxxxxxx,jiang.liu@xxxxxxxxxx,vgupta@xxxxxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Mon, 08 Jul 2013 12:26:34 -0700
The patch titled
Subject: vmlinux.lds: add comments for global variables and clean up useless declarations
has been removed from the -mm tree. Its filename was
vmlinuxlds-add-comments-for-global-variables-and-clean-up-useless-declarations.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Jiang Liu <liuj97@xxxxxxxxx>
Subject: 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@xxxxxxxxxx>
Acked-by: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/asm-generic/sections.h | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
diff -puN include/asm-generic/sections.h~vmlinuxlds-add-comments-for-global-variables-and-clean-up-useless-declarations include/asm-generic/sections.h
--- a/include/asm-generic/sections.h~vmlinuxlds-add-comments-for-global-variables-and-clean-up-useless-declarations
+++ a/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. */
_
Patches currently in -mm which might be from liuj97@xxxxxxxxx are
origin.patch
linux-next.patch
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