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3.2.2 Linux Äں˰ó¶¨ÔÚ¾Ö²¿´æ´¢Æ÷´úÂëʵÏÖ
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1)       ÔÚinit/main.cÕâ¸öÎļþÖÐ,ÔÚÕâÒ»¶Î´úÂë
#ifdef CONFIG_X86_LOCAL_APIC
#include <asm/smp.h>
#endif
µÄÏÂÃæÔö¼ÓÕâ¶Î´úÂë:
unsigned long max_normal_low_pfn=0;
EXPORT_SYMBOL(max_normal_low_pfn); 
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2)       arch/x86/kernel/setup.cÕâ¸öÎļþ£º
l         ÔÚstruct boot_params boot_params;
#endifÖ®ºóÌí¼Ó£¬ÉùÃ÷¸Ã±äÁ¿ÒѾ­ÔÚ±ðµÄÎļþÓж¨ÒåÁË
extern unsigned long max_normal_low_pfn;
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        max_normal_low_pfn = max_low_pfn/2;
        ¸Ã¾äÓÃÓÚ¼ÆËãÐÂÇø(ZONE_NORMAL_LOW)µÄ×î´ó¿ÉÓÃÒ³¿òºÅ¡£
3)       ÔÚarch/x86/mm/init_32.cÎļþ
l         ÔÚunsigned long max_low_pfn_mapped; unsigned long max_pfn_mapped;Ö®ºóÌí¼Óextern unsigned long max_normal_low_pfn;
l         ÔÚstatic void __init zone_sizes_init(void)Õâ¸öº¯ÊýÖÐÔö¼ÓÕâ¾ä´ú


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LinuxÃüÁî find grep vim²å¼þ

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{
struct cdev cdev;
unsigned char mem[MEMSIZE];
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fork compare to exec in linux c program

pid_t  pid=fork()
it has 3 situation for the return result pid
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<0 fork fail
fork create a new process  and it parent live alse when the child process had been created ......

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