简介：介绍一下上文遗留的两个结构memblock以及meminfo.
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* 在arch/arm/kernel/setup.c中，* sanity_check_meminfo();
**********************************arm_memblock_init(&meminfo, mdesc);
arch/arm/mm中，void __init sanity_check_meminfo(void){int i, j, highmem = 0;
//遍历所有的bankfor (i = 0, j = 0; i < meminfo.nr_banks; i++) {struct membank *bank = &meminfo.bank[j];*bank = meminfo.bank[i];
#ifdef CONFIG_HIGHMEM//如果定义了高端内存，地址范围在高端内，则标记if (__va(bank->start) >= vmalloc_min || __va(bank->start) < (void *)PAGE_OFFSET)highmem = 1;
bank->highmem = highmem; //标记
/* * Split those memory banks which are partially overlapping * the vmalloc area greatly simplifying things later. */ //范围在低端内存，但是size大于低端范围也就是 //起始地址在低端，结束地址超过低端范围if (__va(bank->start) < vmalloc_min && bank->size > vmalloc_min – __va(bank->start)) { //banks号大于等于总数量，则直接忽略该bank //否则将该bank分成两个bank，高端部分标记成高端if (meminfo.nr_banks >= NR_BANKS) {printk(KERN_CRIT “NR_BANKS too low, ” “ignoring high memory\n”);} else {memmove(bank + 1, bank,(meminfo.nr_banks – i) * sizeof(*bank));meminfo.nr_banks++;i++;bank[1].size -= vmalloc_min – __va(bank->start);bank[1].start = __pa(vmalloc_min – 1) + 1;bank[1].highmem = highmem = 1;j++;}bank->size = vmalloc_min – __va(bank->start);}#elsebank->highmem = highmem; //没定义就赋值为0
/* * Check whether this memory bank would entirely overlap * the vmalloc area. */ //没定义高端地址，那么高端部分全部忽略if (__va(bank->start) >= vmalloc_min || __va(bank->start) < (void *)PAGE_OFFSET) {printk(KERN_NOTICE “Ignoring RAM at %.8llx-%.8llx ” “(vmalloc region overlap).\n”, (unsigned long long)bank->start, (unsigned long long)bank->start + bank->size – 1);continue;}
/* * Check whether this memory bank would partially overlap * the vmalloc area. */if (__va(bank->start + bank->size) > vmalloc_min || __va(bank->start + bank->size) < __va(bank->start)) {unsigned long newsize = vmalloc_min – __va(bank->start);printk(KERN_NOTICE “Truncating RAM at %.8llx-%.8llx ” “to -%.8llx (vmalloc region overlap).\n”, (unsigned long long)bank->start, (unsigned long long)bank->start + bank->size – 1, (unsigned long long)bank->start + newsize – 1);bank->size = newsize;}#endifif (!bank->highmem && bank->start + bank->size > lowmem_limit)lowmem_limit = bank->start + bank->size;
j++;}#ifdef CONFIG_HIGHMEM //如果是高端内存，，还要进行进一步支持的确认，vipt的不支持if (highmem) {const char *reason = NULL;
if (cache_is_vipt_aliasing()) {/* * Interactions between kmap and other mappings * make highmem support with aliasing VIPT caches * rather difficult. */reason = “with VIPT aliasing cache”;}if (reason) {printk(KERN_CRIT “HIGHMEM is not supported %s, ignoring high memory\n”,reason);while (j > 0 && meminfo.bank[j – 1].highmem)j–;}}#endifmeminfo.nr_banks = j;memblock_set_current_limit(lowmem_limit);}
这里其中vmalloc_vin 定义为static void * __initdata vmalloc_min = (void *)(VMALLOC_END – SZ_128M);而vmalloc_end在2440上定义为arch/arm/mach-s3c2410/include/mach/vmalloc.h#define VMALLOC_END0xF6000000UL
旅游时最好的习惯：找个舒适的小店，挑张雅致的明信片，
