vm_map_ram (9) - Linux Manuals

vm_map_ram: map pages linearly into kernel virtual address (vmalloc space)

Command to display vm_map_ram manual in Linux: $ man 9 vm_map_ram

NAME

vm_map_ram - map pages linearly into kernel virtual address (vmalloc space)

SYNOPSIS

void * vm_map_ram(struct page ** pages, unsigned int count, int node, pgprot_t prot);

ARGUMENTS

pages

: an array of pointers to the pages to be mapped

count

: number of pages

node

: prefer to allocate data structures on this node

prot

: memory protection to use. PAGE_KERNEL for regular RAM

DESCRIPTION

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.

RETURN

a pointer to the address that has been mapped, or NULL on failure