Function kmem_alloc_contig_domain

freebsd/vm/vm_kern.c:288–331

* Allocates a region from the kernel address map and physically * contiguous pages within the specified address range to the kernel * object. Creates a wired mapping from this region to these pages, and * returns the region's starting virtual address. If M_ZERO is specified * through the given flags, then the pages are zeroed before they are * mapped. */

 *	mapped.
 */
static vm_offset_t
kmem_alloc_contig_domain(int domain, vm_size_t size, int flags, vm_paddr_t low,
    vm_paddr_t high, u_long alignment, vm_paddr_t boundary,
    vm_memattr_t memattr)
{
	vmem_t *vmem;
	vm_object_t object;
	vm_offset_t addr, offset, tmp;
	vm_page_t end_m, m;
	u_long npages;
	int pflags;

	object = kernel_object;
	size = round_page(size);
	vmem = vm_dom[domain].vmd_kernel_arena;
	if (vmem_alloc(vmem, size, flags | M_BESTFIT, &addr))
		return (0);
	offset = addr - VM_MIN_KERNEL_ADDRESS;
	pflags = malloc2vm_flags(flags) | VM_ALLOC_WIRED;
	npages = atop(size);
	VM_OBJECT_WLOCK(object);
	m = kmem_alloc_contig_pages(object, atop(offset), domain,
	    pflags, npages, low, high, alignment, boundary, memattr);
	if (m == NULL) {
		VM_OBJECT_WUNLOCK(object);
		vmem_free(vmem, addr, size);
		return (0);
	}
	KASSERT(vm_page_domain(m) == domain,
	    ("kmem_alloc_contig_domain: Domain mismatch %d != %d",
	    vm_page_domain(m), domain));
	end_m = m + npages;
	tmp = addr;
	for (; m < end_m; m++) {
		if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0)
			pmap_zero_page(m);
		vm_page_valid(m);
		pmap_enter(kernel_pmap, tmp, m, VM_PROT_RW,
		    VM_PROT_RW | PMAP_ENTER_WIRED, 0);
		tmp += PAGE_SIZE;
	}
	VM_OBJECT_WUNLOCK(object);
	return (addr);
}

vm_offset_t
kmem_alloc_contig(vm_size_t size, int flags, vm_paddr_t low, vm_paddr_t high,