内存管理初始化（六）vmalloc_init及ioremap

void vmalloc_init(void)|-->for_each_possible_cpu(i)|--{| struct vmap_block_queue *vbq;| vbq &＃61; &per_cpu(vmap_block_queue, i);| spin_lock_init(&vbp->lock);| INIT_LIST_HEAD(&vbq->free);|--}||--for(tmp &＃61; vmlist; tmp; tmp &＃61; tmp->next)|--{| xxxxxxxx| 对于2.6.34的ARM架构而言&＃xff0c;vmlist直到此时仍为0;| 所以该循环不会执行&＃xff0c;至于网上的资料大概是针对X86的.|--}||--vmap_area_pcpu_hole &＃61; VMALLOC_END;| vmap_initialized &＃61; true;

#define ioremap(COOKIE, size) \__arm_ioremap(COOKIE, size, MT_DEVICE)void *__arm_ioremap(unsigned long phys_addr, size_t size,
unsigned int mtype)
|-->__arm_ioremap_caller(phys_addr, size, mtype, NULL)void *__arm_ioremap_caller(unsigned long phys_addr, size_t size,unsigned int mtype, void *caller)|-->unsigned long offset &＃61; phys_addr & ~PAGE_MASK;| 对于SOC&＃xff0c;例如sep612&＃xff0c;每个IP模块的所占空间都是4K的整数倍&＃xff0c;所以| 一般情况下offset &＃61; 0;||-->unsigned long pfn &＃61; __phys_to_pfn(phys_addr);||-->return __arm_ioremap_pfn_caller(pfn, offset, size, mtype, caller);

void *__arm_ioremap_pfn_caller(unsigned long pfn, unsigned long offset,size_t size, unsigned int mtype, void *caller)|-->const struct mem_type *type &＃61; get_mem_type(mtype)| mem_type中存放页表映射属性&＃xff0c;及页表的级数||-->size &＃61; PAGE_ALIGN(offset &＃43; size);||-->struct vm_struct *area &＃61; get_vm_area_caller(size, VM_IOREMAP,
| caller);| 根据size&＃xff0c;在VMALLOC_START ~ VMALLOC_END中申请一块size &＃43; PAGE_SIZE| 大小的虚拟空间&＃xff0c;由于非连续内存区域的管理还利用了红黑树&＃xff0c;因此在获得vm_struct| 实例的同时&＃xff0c;也将申请vmap_area实例&＃xff0c;将申请的虚拟空间&＃xff0c;纳入红黑树| vmap_area_root.rb_node的管理.||-->unsigned long addr &＃61; (unsigned long)area->addr;||-->remap_area_pages(addr, pfn, size, type);| 前面讲过&＃xff0c;申请的虚拟空间是size &＃43; PAGE_SIZE&＃xff0c;此处我们看到&＃xff0c;| 映射的物理空间大小是size.||-->flush_cache_vmap(addr, addr&＃43;size);||-->return (void *) (offset &＃43; addr);

struct vm_struct *get_vm_area_caller(unsigned long size,unsigned long flags, void *caller)|-->return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END, -1, GFP_KERNEL, caller);struct vm_struct *__get_vm_area_node(unsigned long size,unsigned long align, unsigned long flags,unsigned long start, unsigned long end,int node, gfp_t gfp_mask, void *caller)|-->struct vmap_area *va &＃61; NULL;| struct vm_struct *area &＃61; NULL;||-->if(flags & VM_IOREMAP)|--{| int bit &＃61; fls(size);| if(bit > IOREMAP_MAX_ORDER) bit &＃61; IOREMAP_MAX_ORDER;| else if(bit PAGE_SHIFT;| align &＃61; 1 << bit;|--}| 对于IO 映射部分做了对其修正.|||-->size &＃61; PAGE_ALIGN(size);||-->area &＃61; kzalloc_node(sizeof(*area), gfp_mask & GPF_RECLAIM_MASK,
| node);| 对于非连续内存区&＃xff0c;既使用了vmlist这样的链表管理&＃xff0c;也使用了vmap_area_root| 之类的红黑树进行管理&＃xff0c;此处即申请需插入到vmlist链表中的vm_struct实例中.||-->size &＃43;&＃61; PAGE_SIZE;| 为了安全考虑&＃xff0c;多申请了一页的虚拟空间&＃xff08;注意只是虚拟空间&＃xff09;.||-->va &＃61; alloc_vmap_area(size, align, start, end, node, gpf_mask);| 从虚拟内存start ~ end中申请一块size大小的虚拟空间&＃xff0c;起止地址放在| vmap_area实例中&＃xff0c;并将该vmap_area实例插入到以vmap_area_root.rb_node| 为根的红黑树中.||-->insert_vmalloc_vm(area, va, flags, caller);| 将vmap_area实例和vm_struct实例关联起来&＃xff0c;并将vm_struct实例插入到| vmlist链表中.

将vmap_area实例和vm_struct实例关联起来&＃xff0c;并将vm_struct实例插入到vmlist链表中.
void insert_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va)|-->struct vm_struct *tmp, **p;||-->vm->flags &＃61; flags;| vm->addr &＃61; (void *)va->va_start;| vm->size &＃61; va->va_end - va->va_start;| vm->caller &＃61; caller;| va->private &＃61; vm;| va->flags |&＃61; VM_VM_AREA;||-->for(p &＃61; &vmlist; (tmp &＃61; *p) !&＃61; NULL; p &＃61; &tmp->next)|--{| if(tmp->addr >&＃61; vm->addr) break;|--}||--vm->next &＃61; *p;| *p &＃61; vm;