Function max_order

freebsd/vm/vm_phys.c:1126–1139

* Return the largest possible order of a set of pages starting at m. */

 * Return the largest possible order of a set of pages starting at m.
 */
static int
max_order(vm_page_t m)
{

	/*
	 * Unsigned "min" is used here so that "order" is assigned
	 * "VM_NFREEORDER - 1" when "m"'s physical address is zero
	 * or the low-order bits of its physical address are zero
	 * because the size of a physical address exceeds the size of
	 * a long.
	 */
	return (min(ffsl(VM_PAGE_TO_PHYS(m) >> PAGE_SHIFT) - 1,
	    VM_NFREEORDER - 1));
}

/*
 * Free a contiguous, arbitrarily sized set of physical pages, without