AcoSail/kernel_optimize_test
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Blackfin arch: move the init sections to the end of memory to help decrease memory fragementation

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move the init sections to the end of memory, so that after they
are free, run time memory is all continugous - this should help decrease
memory fragementation. When doing this, we also pack some of the other
sections a little closer together, to make sure we don't waste memory.
To make this happen, we need to rename the .data.init_task section to
.init_task.data, so it doesn't get picked up by the linker script glob.

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
This commit is contained in:
Robin Getz 2007-11-15 20:57:53 +08:00 committed by Bryan Wu
parent 74ce8322bf
commit 839e01c2bf
3 changed files with 33 additions and 24 deletions
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2
arch/blackfin/kernel/init_task.c
View File

@ -57,5 +57,5 @@ EXPORT_SYMBOL(init_task);
* "init_task" linker map entry.
*/
union thread_union init_thread_union
__attribute__ ((__section__(".data.init_task"))) = {
__attribute__ ((__section__(".init_task.data"))) = {
INIT_THREAD_INFO(init_task)};

8
arch/blackfin/kernel/setup.c
View File

@ -236,7 +236,7 @@ void __init setup_arch(char **cmdline_p)
/* by now the stack is part of the init task */
memory_end = _ramend - DMA_UNCACHED_REGION;
_ramstart = (unsigned long)__bss_stop;
_ramstart = (unsigned long)_end;
memory_start = PAGE_ALIGN(_ramstart);
#if defined(CONFIG_MTD_UCLINUX)
@ -285,7 +285,7 @@ void __init setup_arch(char **cmdline_p)
}
/* Relocate MTD image to the top of memory after the uncached memory area */
dma_memcpy((char *)memory_end, __bss_stop, mtd_size);
dma_memcpy((char *)memory_end, _end, mtd_size);
memory_mtd_start = memory_end;
_ebss = memory_mtd_start; /* define _ebss for compatible */
@ -357,10 +357,10 @@ void __init setup_arch(char **cmdline_p)
printk(KERN_INFO "Memory map:\n"
KERN_INFO " text = 0x%p-0x%p\n"
KERN_INFO " rodata = 0x%p-0x%p\n"
KERN_INFO " bss = 0x%p-0x%p\n"
KERN_INFO " data = 0x%p-0x%p\n"
KERN_INFO " stack = 0x%p-0x%p\n"
KERN_INFO " init = 0x%p-0x%p\n"
KERN_INFO " bss = 0x%p-0x%p\n"
KERN_INFO " available = 0x%p-0x%p\n"
#ifdef CONFIG_MTD_UCLINUX
KERN_INFO " rootfs = 0x%p-0x%p\n"
@ -370,10 +370,10 @@ void __init setup_arch(char **cmdline_p)
#endif
, _stext, _etext,
__start_rodata, __end_rodata,
__bss_start, __bss_stop,
_sdata, _edata,
(void *)&init_thread_union, (void *)((int)(&init_thread_union) + 0x2000),
__init_begin, __init_end,
__bss_start, __bss_stop,
(void *)_ramstart, (void *)memory_end
#ifdef CONFIG_MTD_UCLINUX
, (void *)memory_mtd_start, (void *)(memory_mtd_start + mtd_size)

47
arch/blackfin/kernel/vmlinux.lds.S
View File

@ -41,6 +41,9 @@ _jiffies = _jiffies_64;
SECTIONS
{
. = CONFIG_BOOT_LOAD;
/* Neither the text, ro_data or bss section need to be aligned
* So pack them back to back
*/
.text :
{
__text = .;
@ -58,22 +61,25 @@ SECTIONS
*(__ex_table)
___stop___ex_table = .;
. = ALIGN(4);
__etext = .;
}
RO_DATA(PAGE_SIZE)
/* Just in case the first read only is a 32-bit access */
RO_DATA(4)
.bss :
{
. = ALIGN(4);
___bss_start = .;
*(.bss .bss.*)
*(COMMON)
___bss_stop = .;
}
.data :
{
/* make sure the init_task is aligned to the
* kernel thread size so we can locate the kernel
* stack properly and quickly.
*/
__sdata = .;
. = ALIGN(THREAD_SIZE);
*(.data.init_task)
/* This gets done first, so the glob doesn't suck it in */
. = ALIGN(32);
*(.data.cacheline_aligned)
@ -81,10 +87,22 @@ SECTIONS
*(.data.*)
CONSTRUCTORS
/* make sure the init_task is aligned to the
* kernel thread size so we can locate the kernel
* stack properly and quickly.
*/
. = ALIGN(THREAD_SIZE);
*(.init_task.data)
__edata = .;
}
/* The init section should be last, so when we free it, it goes into
* the general memory pool, and (hopefully) will decrease fragmentation
* a tiny bit. The init section has a _requirement_ that it be
* PAGE_SIZE aligned
*/
. = ALIGN(PAGE_SIZE);
___init_begin = .;
.init.text :
@ -179,16 +197,7 @@ SECTIONS
. = ALIGN(PAGE_SIZE);
___init_end = .;
.bss :
{
. = ALIGN(4);
___bss_start = .;
*(.bss .bss.*)
*(COMMON)
. = ALIGN(4);
___bss_stop = .;
__end = .;
}
__end =.;
STABS_DEBUG