vm_map_ram — map pages linearly into kernel virtual address (vmalloc space)
| void * vm_map_ram ( | struct page ** pages, | 
| unsigned int count, | |
| int node, | |
| pgprot_t prot ); | 
pagesan array of pointers to the pages to be mapped
countnumber of pages
nodeprefer to allocate data structures on this node
protmemory protection to use. PAGE_KERNEL for regular RAM
   If you use this function for less than VMAP_MAX_ALLOC pages, it could be
   faster than vmap so it's good.  But if you mix long-life and short-life
   objects with vm_map_ram, it could consume lots of address space through
   fragmentation (especially on a 32bit machine).  You could see failures in
   the end.  Please use this function for short-lived objects.