Function pmap_advise

freebsd/arm/arm/pmap-v6.c:5578–5669

* Apply the given advice to the specified range of addresses within the * given pmap. Depending on the advice, clear the referenced and/or * modified flags in each mapping and set the mapped page's dirty field. */

 *	modified flags in each mapping and set the mapped page's dirty field.
 */
void
pmap_advise(pmap_t pmap, vm_offset_t sva, vm_offset_t eva, int advice)
{
	pt1_entry_t *pte1p, opte1;
	pt2_entry_t *pte2p, pte2;
	vm_offset_t pdnxt;
	vm_page_t m;
	boolean_t pv_lists_locked;

	if (advice != MADV_DONTNEED && advice != MADV_FREE)
		return;
	if (pmap_is_current(pmap))
		pv_lists_locked = FALSE;
	else {
		pv_lists_locked = TRUE;
resume:
		rw_wlock(&pvh_global_lock);
		sched_pin();
	}
	PMAP_LOCK(pmap);
	for (; sva < eva; sva = pdnxt) {
		pdnxt = pte1_trunc(sva + PTE1_SIZE);
		if (pdnxt < sva)
			pdnxt = eva;
		pte1p = pmap_pte1(pmap, sva);
		opte1 = pte1_load(pte1p);
		if (!pte1_is_valid(opte1)) /* XXX */
			continue;
		else if (pte1_is_section(opte1)) {
			if (!pte1_is_managed(opte1))
				continue;
			if (!pv_lists_locked) {
				pv_lists_locked = TRUE;
				if (!rw_try_wlock(&pvh_global_lock)) {
					PMAP_UNLOCK(pmap);
					goto resume;
				}
				sched_pin();
			}
			if (!pmap_demote_pte1(pmap, pte1p, sva)) {
				/*
				 * The large page mapping was destroyed.
				 */
				continue;
			}

			/*
			 * Unless the page mappings are wired, remove the
			 * mapping to a single page so that a subsequent
			 * access may repromote.  Since the underlying L2 page
			 * table is fully populated, this removal never
			 * frees a L2 page table page.
			 */
			if (!pte1_is_wired(opte1)) {
				pte2p = pmap_pte2_quick(pmap, sva);
				KASSERT(pte2_is_valid(pte2_load(pte2p)),
				    ("%s: invalid PTE2", __func__));
				pmap_remove_pte2(pmap, pte2p, sva, NULL);