Function vm_reserv_from_page

freebsd/vm/vm_reserv.c:502–514

* Returns the reservation to which the given page might belong. */

 * Returns the reservation to which the given page might belong.
 */
static __inline vm_reserv_t
vm_reserv_from_page(vm_page_t m)
{
#ifdef VM_PHYSSEG_SPARSE
	struct vm_phys_seg *seg;

	seg = &vm_phys_segs[m->segind];
	return (seg->first_reserv + (VM_PAGE_TO_PHYS(m) >> VM_LEVEL_0_SHIFT) -
	    (seg->start >> VM_LEVEL_0_SHIFT));
#else
	return (&vm_reserv_array[VM_PAGE_TO_PHYS(m) >> VM_LEVEL_0_SHIFT]);
#endif
}

/*
 * Returns an existing reservation or NULL and initialized successor pointer.