278 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
279 kmem_object);
280#if VM_NRESERVLEVEL > 0
281 kmem_object->flags |= OBJ_COLORED;
282 kmem_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS);
283#endif
284
285 /*
286 * The lock portion of struct vm_object must be type stable due
287 * to vm_pageout_fallback_object_lock locking a vm object
288 * without holding any references to it.
289 */
290 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL,
291#ifdef INVARIANTS
292 vm_object_zdtor,
293#else
294 NULL,
295#endif
296 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM|UMA_ZONE_NOFREE);
297}
298
299void
300vm_object_clear_flag(vm_object_t object, u_short bits)
301{
302
303 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
304 object->flags &= ~bits;
305}
306
307/*
308 * Sets the default memory attribute for the specified object. Pages
309 * that are allocated to this object are by default assigned this memory
310 * attribute.
311 *
312 * Presently, this function must be called before any pages are allocated
313 * to the object. In the future, this requirement may be relaxed for
314 * "default" and "swap" objects.
315 */
316int
317vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr)
318{
319
320 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
321 switch (object->type) {
322 case OBJT_DEFAULT:
323 case OBJT_DEVICE:
324 case OBJT_MGTDEVICE:
325 case OBJT_PHYS:
326 case OBJT_SG:
327 case OBJT_SWAP:
328 case OBJT_VNODE:
329 if (!TAILQ_EMPTY(&object->memq))
330 return (KERN_FAILURE);
331 break;
332 case OBJT_DEAD:
333 return (KERN_INVALID_ARGUMENT);
334 default:
335 panic("vm_object_set_memattr: object %p is of undefined type",
336 object);
337 }
338 object->memattr = memattr;
339 return (KERN_SUCCESS);
340}
341
342void
343vm_object_pip_add(vm_object_t object, short i)
344{
345
346 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
347 object->paging_in_progress += i;
348}
349
350void
351vm_object_pip_subtract(vm_object_t object, short i)
352{
353
354 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
355 object->paging_in_progress -= i;
356}
357
358void
359vm_object_pip_wakeup(vm_object_t object)
360{
361
362 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
363 object->paging_in_progress--;
364 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
365 vm_object_clear_flag(object, OBJ_PIPWNT);
366 wakeup(object);
367 }
368}
369
370void
371vm_object_pip_wakeupn(vm_object_t object, short i)
372{
373
374 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
375 if (i)
376 object->paging_in_progress -= i;
377 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
378 vm_object_clear_flag(object, OBJ_PIPWNT);
379 wakeup(object);
380 }
381}
382
383void
384vm_object_pip_wait(vm_object_t object, char *waitid)
385{
386
387 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
388 while (object->paging_in_progress) {
389 object->flags |= OBJ_PIPWNT;
390 VM_OBJECT_SLEEP(object, object, PVM, waitid, 0);
391 }
392}
393
394/*
395 * vm_object_allocate:
396 *
397 * Returns a new object with the given size.
398 */
399vm_object_t
400vm_object_allocate(objtype_t type, vm_pindex_t size)
401{
402 vm_object_t object;
403
404 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK);
405 _vm_object_allocate(type, size, object);
406 return (object);
407}
408
409
410/*
411 * vm_object_reference:
412 *
413 * Gets another reference to the given object. Note: OBJ_DEAD
414 * objects can be referenced during final cleaning.
415 */
416void
417vm_object_reference(vm_object_t object)
418{
419 if (object == NULL)
420 return;
421 VM_OBJECT_LOCK(object);
422 vm_object_reference_locked(object);
423 VM_OBJECT_UNLOCK(object);
424}
425
426/*
427 * vm_object_reference_locked:
428 *
429 * Gets another reference to the given object.
430 *
431 * The object must be locked.
432 */
433void
434vm_object_reference_locked(vm_object_t object)
435{
436 struct vnode *vp;
437
438 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
439 object->ref_count++;
440 if (object->type == OBJT_VNODE) {
441 vp = object->handle;
442 vref(vp);
443 }
444}
445
446/*
447 * Handle deallocating an object of type OBJT_VNODE.
448 */
449static void
450vm_object_vndeallocate(vm_object_t object)
451{
452 struct vnode *vp = (struct vnode *) object->handle;
453
454 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
455 KASSERT(object->type == OBJT_VNODE,
456 ("vm_object_vndeallocate: not a vnode object"));
457 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp"));
458#ifdef INVARIANTS
459 if (object->ref_count == 0) {
460 vprint("vm_object_vndeallocate", vp);
461 panic("vm_object_vndeallocate: bad object reference count");
462 }
463#endif
464
465 if (object->ref_count > 1) {
466 object->ref_count--;
467 VM_OBJECT_UNLOCK(object);
468 /* vrele may need the vnode lock. */
469 vrele(vp);
470 } else {
471 vhold(vp);
472 VM_OBJECT_UNLOCK(object);
473 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
474 vdrop(vp);
475 VM_OBJECT_LOCK(object);
476 object->ref_count--;
477 if (object->type == OBJT_DEAD) {
478 VM_OBJECT_UNLOCK(object);
479 VOP_UNLOCK(vp, 0);
480 } else {
481 if (object->ref_count == 0)
482 VOP_UNSET_TEXT(vp);
483 VM_OBJECT_UNLOCK(object);
484 vput(vp);
485 }
486 }
487}
488
489/*
490 * vm_object_deallocate:
491 *
492 * Release a reference to the specified object,
493 * gained either through a vm_object_allocate
494 * or a vm_object_reference call. When all references
495 * are gone, storage associated with this object
496 * may be relinquished.
497 *
498 * No object may be locked.
499 */
500void
501vm_object_deallocate(vm_object_t object)
502{
503 vm_object_t temp;
504
505 while (object != NULL) {
506 VM_OBJECT_LOCK(object);
507 if (object->type == OBJT_VNODE) {
508 vm_object_vndeallocate(object);
509 return;
510 }
511
512 KASSERT(object->ref_count != 0,
513 ("vm_object_deallocate: object deallocated too many times: %d", object->type));
514
515 /*
516 * If the reference count goes to 0 we start calling
517 * vm_object_terminate() on the object chain.
518 * A ref count of 1 may be a special case depending on the
519 * shadow count being 0 or 1.
520 */
521 object->ref_count--;
522 if (object->ref_count > 1) {
523 VM_OBJECT_UNLOCK(object);
524 return;
525 } else if (object->ref_count == 1) {
526 if (object->shadow_count == 0 &&
527 object->handle == NULL &&
528 (object->type == OBJT_DEFAULT ||
529 object->type == OBJT_SWAP)) {
530 vm_object_set_flag(object, OBJ_ONEMAPPING);
531 } else if ((object->shadow_count == 1) &&
532 (object->handle == NULL) &&
533 (object->type == OBJT_DEFAULT ||
534 object->type == OBJT_SWAP)) {
535 vm_object_t robject;
536
537 robject = LIST_FIRST(&object->shadow_head);
538 KASSERT(robject != NULL,
539 ("vm_object_deallocate: ref_count: %d, shadow_count: %d",
540 object->ref_count,
541 object->shadow_count));
542 if (!VM_OBJECT_TRYLOCK(robject)) {
543 /*
544 * Avoid a potential deadlock.
545 */
546 object->ref_count++;
547 VM_OBJECT_UNLOCK(object);
548 /*
549 * More likely than not the thread
550 * holding robject's lock has lower
551 * priority than the current thread.
552 * Let the lower priority thread run.
553 */
554 pause("vmo_de", 1);
555 continue;
556 }
557 /*
558 * Collapse object into its shadow unless its
559 * shadow is dead. In that case, object will
560 * be deallocated by the thread that is
561 * deallocating its shadow.
562 */
563 if ((robject->flags & OBJ_DEAD) == 0 &&
564 (robject->handle == NULL) &&
565 (robject->type == OBJT_DEFAULT ||
566 robject->type == OBJT_SWAP)) {
567
568 robject->ref_count++;
569retry:
570 if (robject->paging_in_progress) {
571 VM_OBJECT_UNLOCK(object);
572 vm_object_pip_wait(robject,
573 "objde1");
574 temp = robject->backing_object;
575 if (object == temp) {
576 VM_OBJECT_LOCK(object);
577 goto retry;
578 }
579 } else if (object->paging_in_progress) {
580 VM_OBJECT_UNLOCK(robject);
581 object->flags |= OBJ_PIPWNT;
582 VM_OBJECT_SLEEP(object, object,
583 PDROP | PVM, "objde2", 0);
584 VM_OBJECT_LOCK(robject);
585 temp = robject->backing_object;
586 if (object == temp) {
587 VM_OBJECT_LOCK(object);
588 goto retry;
589 }
590 } else
591 VM_OBJECT_UNLOCK(object);
592
593 if (robject->ref_count == 1) {
594 robject->ref_count--;
595 object = robject;
596 goto doterm;
597 }
598 object = robject;
599 vm_object_collapse(object);
600 VM_OBJECT_UNLOCK(object);
601 continue;
602 }
603 VM_OBJECT_UNLOCK(robject);
604 }
605 VM_OBJECT_UNLOCK(object);
606 return;
607 }
608doterm:
609 temp = object->backing_object;
610 if (temp != NULL) {
611 VM_OBJECT_LOCK(temp);
612 LIST_REMOVE(object, shadow_list);
613 temp->shadow_count--;
614 VM_OBJECT_UNLOCK(temp);
615 object->backing_object = NULL;
616 }
617 /*
618 * Don't double-terminate, we could be in a termination
619 * recursion due to the terminate having to sync data
620 * to disk.
621 */
622 if ((object->flags & OBJ_DEAD) == 0)
623 vm_object_terminate(object);
624 else
625 VM_OBJECT_UNLOCK(object);
626 object = temp;
627 }
628}
629
630/*
631 * vm_object_destroy removes the object from the global object list
632 * and frees the space for the object.
633 */
634void
635vm_object_destroy(vm_object_t object)
636{
637
638 /*
639 * Remove the object from the global object list.
640 */
641 mtx_lock(&vm_object_list_mtx);
642 TAILQ_REMOVE(&vm_object_list, object, object_list);
643 mtx_unlock(&vm_object_list_mtx);
644
645 /*
646 * Release the allocation charge.
647 */
648 if (object->cred != NULL) {
649 KASSERT(object->type == OBJT_DEFAULT ||
650 object->type == OBJT_SWAP,
651 ("vm_object_terminate: non-swap obj %p has cred",
652 object));
653 swap_release_by_cred(object->charge, object->cred);
654 object->charge = 0;
655 crfree(object->cred);
656 object->cred = NULL;
657 }
658
659 /*
660 * Free the space for the object.
661 */
662 uma_zfree(obj_zone, object);
663}
664
665/*
666 * vm_object_terminate actually destroys the specified object, freeing
667 * up all previously used resources.
668 *
669 * The object must be locked.
670 * This routine may block.
671 */
672void
673vm_object_terminate(vm_object_t object)
674{
675 vm_page_t p, p_next;
676
677 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
678
679 /*
680 * Make sure no one uses us.
681 */
682 vm_object_set_flag(object, OBJ_DEAD);
683
684 /*
685 * wait for the pageout daemon to be done with the object
686 */
687 vm_object_pip_wait(object, "objtrm");
688
689 KASSERT(!object->paging_in_progress,
690 ("vm_object_terminate: pageout in progress"));
691
692 /*
693 * Clean and free the pages, as appropriate. All references to the
694 * object are gone, so we don't need to lock it.
695 */
696 if (object->type == OBJT_VNODE) {
697 struct vnode *vp = (struct vnode *)object->handle;
698
699 /*
700 * Clean pages and flush buffers.
701 */
702 vm_object_page_clean(object, 0, 0, OBJPC_SYNC);
703 VM_OBJECT_UNLOCK(object);
704
705 vinvalbuf(vp, V_SAVE, 0, 0);
706
707 VM_OBJECT_LOCK(object);
708 }
709
710 KASSERT(object->ref_count == 0,
711 ("vm_object_terminate: object with references, ref_count=%d",
712 object->ref_count));
713
714 /*
715 * Free any remaining pageable pages. This also removes them from the
716 * paging queues. However, don't free wired pages, just remove them
717 * from the object. Rather than incrementally removing each page from
718 * the object, the page and object are reset to any empty state.
719 */
720 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) {
721 KASSERT(!p->busy && (p->oflags & VPO_BUSY) == 0,
722 ("vm_object_terminate: freeing busy page %p", p));
723 vm_page_lock(p);
724 /*
725 * Optimize the page's removal from the object by resetting
726 * its "object" field. Specifically, if the page is not
727 * wired, then the effect of this assignment is that
728 * vm_page_free()'s call to vm_page_remove() will return
729 * immediately without modifying the page or the object.
730 */
731 p->object = NULL;
732 if (p->wire_count == 0) {
733 vm_page_free(p);
734 PCPU_INC(cnt.v_pfree);
735 }
736 vm_page_unlock(p);
737 }
738 /*
739 * If the object contained any pages, then reset it to an empty state.
740 * None of the object's fields, including "resident_page_count", were
741 * modified by the preceding loop.
742 */
743 if (object->resident_page_count != 0) {
744 object->root = NULL;
745 TAILQ_INIT(&object->memq);
746 object->resident_page_count = 0;
747 if (object->type == OBJT_VNODE)
748 vdrop(object->handle);
749 }
750
751#if VM_NRESERVLEVEL > 0
752 if (__predict_false(!LIST_EMPTY(&object->rvq)))
753 vm_reserv_break_all(object);
754#endif
755 if (__predict_false(object->cache != NULL))
756 vm_page_cache_free(object, 0, 0);
757
758 /*
759 * Let the pager know object is dead.
760 */
761 vm_pager_deallocate(object);
762 VM_OBJECT_UNLOCK(object);
763
764 vm_object_destroy(object);
765}
766
767/*
768 * Make the page read-only so that we can clear the object flags. However, if
769 * this is a nosync mmap then the object is likely to stay dirty so do not
770 * mess with the page and do not clear the object flags. Returns TRUE if the
771 * page should be flushed, and FALSE otherwise.
772 */
773static boolean_t
774vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *clearobjflags)
775{
776
777 /*
778 * If we have been asked to skip nosync pages and this is a
779 * nosync page, skip it. Note that the object flags were not
780 * cleared in this case so we do not have to set them.
781 */
782 if ((flags & OBJPC_NOSYNC) != 0 && (p->oflags & VPO_NOSYNC) != 0) {
783 *clearobjflags = FALSE;
784 return (FALSE);
785 } else {
786 pmap_remove_write(p);
787 return (p->dirty != 0);
788 }
789}
790
791/*
792 * vm_object_page_clean
793 *
794 * Clean all dirty pages in the specified range of object. Leaves page
795 * on whatever queue it is currently on. If NOSYNC is set then do not
796 * write out pages with VPO_NOSYNC set (originally comes from MAP_NOSYNC),
797 * leaving the object dirty.
798 *
799 * When stuffing pages asynchronously, allow clustering. XXX we need a
800 * synchronous clustering mode implementation.
801 *
802 * Odd semantics: if start == end, we clean everything.
803 *
804 * The object must be locked.
805 *
806 * Returns FALSE if some page from the range was not written, as
807 * reported by the pager, and TRUE otherwise.
808 */
809boolean_t
810vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end,
811 int flags)
812{
813 vm_page_t np, p;
814 vm_pindex_t pi, tend, tstart;
815 int curgeneration, n, pagerflags;
816 boolean_t clearobjflags, eio, res;
817
818 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
819 KASSERT(object->type == OBJT_VNODE, ("Not a vnode object"));
820 if ((object->flags & OBJ_MIGHTBEDIRTY) == 0 ||
821 object->resident_page_count == 0)
822 return (TRUE);
823
824 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ?
825 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK;
826 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0;
827
828 tstart = OFF_TO_IDX(start);
829 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK);
830 clearobjflags = tstart == 0 && tend >= object->size;
831 res = TRUE;
832
833rescan:
834 curgeneration = object->generation;
835
836 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) {
837 pi = p->pindex;
838 if (pi >= tend)
839 break;
840 np = TAILQ_NEXT(p, listq);
841 if (p->valid == 0)
842 continue;
843 if (vm_page_sleep_if_busy(p, TRUE, "vpcwai")) {
844 if (object->generation != curgeneration) {
845 if ((flags & OBJPC_SYNC) != 0)
846 goto rescan;
847 else
848 clearobjflags = FALSE;
849 }
850 np = vm_page_find_least(object, pi);
851 continue;
852 }
853 if (!vm_object_page_remove_write(p, flags, &clearobjflags))
854 continue;
855
856 n = vm_object_page_collect_flush(object, p, pagerflags,
857 flags, &clearobjflags, &eio);
858 if (eio) {
859 res = FALSE;
860 clearobjflags = FALSE;
861 }
862 if (object->generation != curgeneration) {
863 if ((flags & OBJPC_SYNC) != 0)
864 goto rescan;
865 else
866 clearobjflags = FALSE;
867 }
868
869 /*
870 * If the VOP_PUTPAGES() did a truncated write, so
871 * that even the first page of the run is not fully
872 * written, vm_pageout_flush() returns 0 as the run
873 * length. Since the condition that caused truncated
874 * write may be permanent, e.g. exhausted free space,
875 * accepting n == 0 would cause an infinite loop.
876 *
877 * Forwarding the iterator leaves the unwritten page
878 * behind, but there is not much we can do there if
879 * filesystem refuses to write it.
880 */
881 if (n == 0) {
882 n = 1;
883 clearobjflags = FALSE;
884 }
885 np = vm_page_find_least(object, pi + n);
886 }
887#if 0
888 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0);
889#endif
890
891 if (clearobjflags)
892 vm_object_clear_flag(object, OBJ_MIGHTBEDIRTY);
893 return (res);
894}
895
896static int
897vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags,
898 int flags, boolean_t *clearobjflags, boolean_t *eio)
899{
900 vm_page_t ma[vm_pageout_page_count], p_first, tp;
901 int count, i, mreq, runlen;
902
903 vm_page_lock_assert(p, MA_NOTOWNED);
904 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
905
906 count = 1;
907 mreq = 0;
908
909 for (tp = p; count < vm_pageout_page_count; count++) {
910 tp = vm_page_next(tp);
911 if (tp == NULL || tp->busy != 0 || (tp->oflags & VPO_BUSY) != 0)
912 break;
913 if (!vm_object_page_remove_write(tp, flags, clearobjflags))
914 break;
915 }
916
917 for (p_first = p; count < vm_pageout_page_count; count++) {
918 tp = vm_page_prev(p_first);
919 if (tp == NULL || tp->busy != 0 || (tp->oflags & VPO_BUSY) != 0)
920 break;
921 if (!vm_object_page_remove_write(tp, flags, clearobjflags))
922 break;
923 p_first = tp;
924 mreq++;
925 }
926
927 for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++)
928 ma[i] = tp;
929
930 vm_pageout_flush(ma, count, pagerflags, mreq, &runlen, eio);
931 return (runlen);
932}
933
934/*
935 * Note that there is absolutely no sense in writing out
936 * anonymous objects, so we track down the vnode object
937 * to write out.
938 * We invalidate (remove) all pages from the address space
939 * for semantic correctness.
940 *
941 * If the backing object is a device object with unmanaged pages, then any
942 * mappings to the specified range of pages must be removed before this
943 * function is called.
944 *
945 * Note: certain anonymous maps, such as MAP_NOSYNC maps,
946 * may start out with a NULL object.
947 */
948boolean_t
949vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size,
950 boolean_t syncio, boolean_t invalidate)
951{
952 vm_object_t backing_object;
953 struct vnode *vp;
954 struct mount *mp;
955 int error, flags, fsync_after;
956 boolean_t res;
957
958 if (object == NULL)
959 return (TRUE);
960 res = TRUE;
961 error = 0;
962 VM_OBJECT_LOCK(object);
963 while ((backing_object = object->backing_object) != NULL) {
964 VM_OBJECT_LOCK(backing_object);
965 offset += object->backing_object_offset;
966 VM_OBJECT_UNLOCK(object);
967 object = backing_object;
968 if (object->size < OFF_TO_IDX(offset + size))
969 size = IDX_TO_OFF(object->size) - offset;
970 }
971 /*
972 * Flush pages if writing is allowed, invalidate them
973 * if invalidation requested. Pages undergoing I/O
974 * will be ignored by vm_object_page_remove().
975 *
976 * We cannot lock the vnode and then wait for paging
977 * to complete without deadlocking against vm_fault.
978 * Instead we simply call vm_object_page_remove() and
979 * allow it to block internally on a page-by-page
980 * basis when it encounters pages undergoing async
981 * I/O.
982 */
983 if (object->type == OBJT_VNODE &&
984 (object->flags & OBJ_MIGHTBEDIRTY) != 0) {
985 vp = object->handle;
986 VM_OBJECT_UNLOCK(object);
987 (void) vn_start_write(vp, &mp, V_WAIT);
988 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
989 if (syncio && !invalidate && offset == 0 &&
990 OFF_TO_IDX(size) == object->size) {
991 /*
992 * If syncing the whole mapping of the file,
993 * it is faster to schedule all the writes in
994 * async mode, also allowing the clustering,
995 * and then wait for i/o to complete.
996 */
997 flags = 0;
998 fsync_after = TRUE;
999 } else {
1000 flags = (syncio || invalidate) ? OBJPC_SYNC : 0;
1001 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0;
1002 fsync_after = FALSE;
1003 }
1004 VM_OBJECT_LOCK(object);
1005 res = vm_object_page_clean(object, offset, offset + size,
1006 flags);
1007 VM_OBJECT_UNLOCK(object);
1008 if (fsync_after)
1009 error = VOP_FSYNC(vp, MNT_WAIT, curthread);
1010 VOP_UNLOCK(vp, 0);
1011 vn_finished_write(mp);
1012 if (error != 0)
1013 res = FALSE;
1014 VM_OBJECT_LOCK(object);
1015 }
1016 if ((object->type == OBJT_VNODE ||
1017 object->type == OBJT_DEVICE) && invalidate) {
1018 if (object->type == OBJT_DEVICE)
1019 /*
1020 * The option OBJPR_NOTMAPPED must be passed here
1021 * because vm_object_page_remove() cannot remove
1022 * unmanaged mappings.
1023 */
1024 flags = OBJPR_NOTMAPPED;
1025 else if (old_msync)
1026 flags = 0;
1027 else
1028 flags = OBJPR_CLEANONLY;
1029 vm_object_page_remove(object, OFF_TO_IDX(offset),
1030 OFF_TO_IDX(offset + size + PAGE_MASK), flags);
1031 }
1032 VM_OBJECT_UNLOCK(object);
1033 return (res);
1034}
1035
1036/*
1037 * vm_object_madvise:
1038 *
1039 * Implements the madvise function at the object/page level.
1040 *
1041 * MADV_WILLNEED (any object)
1042 *
1043 * Activate the specified pages if they are resident.
1044 *
1045 * MADV_DONTNEED (any object)
1046 *
1047 * Deactivate the specified pages if they are resident.
1048 *
1049 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects,
1050 * OBJ_ONEMAPPING only)
1051 *
1052 * Deactivate and clean the specified pages if they are
1053 * resident. This permits the process to reuse the pages
1054 * without faulting or the kernel to reclaim the pages
1055 * without I/O.
1056 */
1057void
1058vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end,
1059 int advise)
1060{
1061 vm_pindex_t tpindex;
1062 vm_object_t backing_object, tobject;
1063 vm_page_t m;
1064
1065 if (object == NULL)
1066 return;
1067 VM_OBJECT_LOCK(object);
1068 /*
1069 * Locate and adjust resident pages
1070 */
1071 for (; pindex < end; pindex += 1) {
1072relookup:
1073 tobject = object;
1074 tpindex = pindex;
1075shadowlookup:
1076 /*
1077 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages
1078 * and those pages must be OBJ_ONEMAPPING.
1079 */
1080 if (advise == MADV_FREE) {
1081 if ((tobject->type != OBJT_DEFAULT &&
1082 tobject->type != OBJT_SWAP) ||
1083 (tobject->flags & OBJ_ONEMAPPING) == 0) {
1084 goto unlock_tobject;
1085 }
1086 } else if ((tobject->flags & OBJ_UNMANAGED) != 0)
1087 goto unlock_tobject;
1088 m = vm_page_lookup(tobject, tpindex);
1089 if (m == NULL && advise == MADV_WILLNEED) {
1090 /*
1091 * If the page is cached, reactivate it.
1092 */
1093 m = vm_page_alloc(tobject, tpindex, VM_ALLOC_IFCACHED |
1094 VM_ALLOC_NOBUSY);
1095 }
1096 if (m == NULL) {
1097 /*
1098 * There may be swap even if there is no backing page
1099 */
1100 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1101 swap_pager_freespace(tobject, tpindex, 1);
1102 /*
1103 * next object
1104 */
1105 backing_object = tobject->backing_object;
1106 if (backing_object == NULL)
1107 goto unlock_tobject;
1108 VM_OBJECT_LOCK(backing_object);
1109 tpindex += OFF_TO_IDX(tobject->backing_object_offset);
1110 if (tobject != object)
1111 VM_OBJECT_UNLOCK(tobject);
1112 tobject = backing_object;
1113 goto shadowlookup;
1114 } else if (m->valid != VM_PAGE_BITS_ALL)
1115 goto unlock_tobject;
1116 /*
1117 * If the page is not in a normal state, skip it.
1118 */
1119 vm_page_lock(m);
1120 if (m->hold_count != 0 || m->wire_count != 0) {
1121 vm_page_unlock(m);
1122 goto unlock_tobject;
1123 }
1124 KASSERT((m->flags & PG_FICTITIOUS) == 0,
1125 ("vm_object_madvise: page %p is fictitious", m));
1126 KASSERT((m->oflags & VPO_UNMANAGED) == 0,
1127 ("vm_object_madvise: page %p is not managed", m));
1128 if ((m->oflags & VPO_BUSY) || m->busy) {
1129 if (advise == MADV_WILLNEED) {
1130 /*
1131 * Reference the page before unlocking and
1132 * sleeping so that the page daemon is less
1133 * likely to reclaim it.
1134 */
1135 vm_page_aflag_set(m, PGA_REFERENCED);
1136 }
1137 vm_page_unlock(m);
1138 if (object != tobject)
1139 VM_OBJECT_UNLOCK(object);
1140 m->oflags |= VPO_WANTED;
1141 VM_OBJECT_SLEEP(tobject, m, PDROP | PVM, "madvpo", 0);
1142 VM_OBJECT_LOCK(object);
1143 goto relookup;
1144 }
1145 if (advise == MADV_WILLNEED) {
1146 vm_page_activate(m);
1147 } else if (advise == MADV_DONTNEED) {
1148 vm_page_dontneed(m);
1149 } else if (advise == MADV_FREE) {
1150 /*
1151 * Mark the page clean. This will allow the page
1152 * to be freed up by the system. However, such pages
1153 * are often reused quickly by malloc()/free()
1154 * so we do not do anything that would cause
1155 * a page fault if we can help it.
1156 *
1157 * Specifically, we do not try to actually free
1158 * the page now nor do we try to put it in the
1159 * cache (which would cause a page fault on reuse).
1160 *
1161 * But we do make the page is freeable as we
1162 * can without actually taking the step of unmapping
1163 * it.
1164 */
1165 pmap_clear_modify(m);
1166 m->dirty = 0;
1167 m->act_count = 0;
1168 vm_page_dontneed(m);
1169 }
1170 vm_page_unlock(m);
1171 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1172 swap_pager_freespace(tobject, tpindex, 1);
1173unlock_tobject:
1174 if (tobject != object)
1175 VM_OBJECT_UNLOCK(tobject);
1176 }
1177 VM_OBJECT_UNLOCK(object);
1178}
1179
1180/*
1181 * vm_object_shadow:
1182 *
1183 * Create a new object which is backed by the
1184 * specified existing object range. The source
1185 * object reference is deallocated.
1186 *
1187 * The new object and offset into that object
1188 * are returned in the source parameters.
1189 */
1190void
1191vm_object_shadow(
1192 vm_object_t *object, /* IN/OUT */
1193 vm_ooffset_t *offset, /* IN/OUT */
1194 vm_size_t length)
1195{
1196 vm_object_t source;
1197 vm_object_t result;
1198
1199 source = *object;
1200
1201 /*
1202 * Don't create the new object if the old object isn't shared.
1203 */
1204 if (source != NULL) {
1205 VM_OBJECT_LOCK(source);
1206 if (source->ref_count == 1 &&
1207 source->handle == NULL &&
1208 (source->type == OBJT_DEFAULT ||
1209 source->type == OBJT_SWAP)) {
1210 VM_OBJECT_UNLOCK(source);
1211 return;
1212 }
1213 VM_OBJECT_UNLOCK(source);
1214 }
1215
1216 /*
1217 * Allocate a new object with the given length.
1218 */
1219 result = vm_object_allocate(OBJT_DEFAULT, atop(length));
1220
1221 /*
1222 * The new object shadows the source object, adding a reference to it.
1223 * Our caller changes his reference to point to the new object,
1224 * removing a reference to the source object. Net result: no change
1225 * of reference count.
1226 *
1227 * Try to optimize the result object's page color when shadowing
1228 * in order to maintain page coloring consistency in the combined
1229 * shadowed object.
1230 */
1231 result->backing_object = source;
1232 /*
1233 * Store the offset into the source object, and fix up the offset into
1234 * the new object.
1235 */
1236 result->backing_object_offset = *offset;
1237 if (source != NULL) {
1238 VM_OBJECT_LOCK(source);
1239 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list);
1240 source->shadow_count++;
1241#if VM_NRESERVLEVEL > 0
1242 result->flags |= source->flags & OBJ_COLORED;
1243 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) &
1244 ((1 << (VM_NFREEORDER - 1)) - 1);
1245#endif
1246 VM_OBJECT_UNLOCK(source);
1247 }
1248
1249
1250 /*
1251 * Return the new things
1252 */
1253 *offset = 0;
1254 *object = result;
1255}
1256
1257/*
1258 * vm_object_split:
1259 *
1260 * Split the pages in a map entry into a new object. This affords
1261 * easier removal of unused pages, and keeps object inheritance from
1262 * being a negative impact on memory usage.
1263 */
1264void
1265vm_object_split(vm_map_entry_t entry)
1266{
1267 vm_page_t m, m_next;
1268 vm_object_t orig_object, new_object, source;
1269 vm_pindex_t idx, offidxstart;
1270 vm_size_t size;
1271
1272 orig_object = entry->object.vm_object;
1273 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP)
1274 return;
1275 if (orig_object->ref_count <= 1)
1276 return;
1277 VM_OBJECT_UNLOCK(orig_object);
1278
1279 offidxstart = OFF_TO_IDX(entry->offset);
1280 size = atop(entry->end - entry->start);
1281
1282 /*
1283 * If swap_pager_copy() is later called, it will convert new_object
1284 * into a swap object.
1285 */
1286 new_object = vm_object_allocate(OBJT_DEFAULT, size);
1287
1288 /*
1289 * At this point, the new object is still private, so the order in
1290 * which the original and new objects are locked does not matter.
1291 */
1292 VM_OBJECT_LOCK(new_object);
1293 VM_OBJECT_LOCK(orig_object);
1294 source = orig_object->backing_object;
1295 if (source != NULL) {
1296 VM_OBJECT_LOCK(source);
1297 if ((source->flags & OBJ_DEAD) != 0) {
1298 VM_OBJECT_UNLOCK(source);
1299 VM_OBJECT_UNLOCK(orig_object);
1300 VM_OBJECT_UNLOCK(new_object);
1301 vm_object_deallocate(new_object);
1302 VM_OBJECT_LOCK(orig_object);
1303 return;
1304 }
1305 LIST_INSERT_HEAD(&source->shadow_head,
1306 new_object, shadow_list);
1307 source->shadow_count++;
1308 vm_object_reference_locked(source); /* for new_object */
1309 vm_object_clear_flag(source, OBJ_ONEMAPPING);
1310 VM_OBJECT_UNLOCK(source);
1311 new_object->backing_object_offset =
1312 orig_object->backing_object_offset + entry->offset;
1313 new_object->backing_object = source;
1314 }
1315 if (orig_object->cred != NULL) {
1316 new_object->cred = orig_object->cred;
1317 crhold(orig_object->cred);
1318 new_object->charge = ptoa(size);
1319 KASSERT(orig_object->charge >= ptoa(size),
1320 ("orig_object->charge < 0"));
1321 orig_object->charge -= ptoa(size);
1322 }
1323retry:
1324 m = vm_page_find_least(orig_object, offidxstart);
1325 for (; m != NULL && (idx = m->pindex - offidxstart) < size;
1326 m = m_next) {
1327 m_next = TAILQ_NEXT(m, listq);
1328
1329 /*
1330 * We must wait for pending I/O to complete before we can
1331 * rename the page.
1332 *
1333 * We do not have to VM_PROT_NONE the page as mappings should
1334 * not be changed by this operation.
1335 */
1336 if ((m->oflags & VPO_BUSY) || m->busy) {
1337 VM_OBJECT_UNLOCK(new_object);
1338 m->oflags |= VPO_WANTED;
1339 VM_OBJECT_SLEEP(orig_object, m, PVM, "spltwt", 0);
1340 VM_OBJECT_LOCK(new_object);
1341 goto retry;
1342 }
1343#if VM_NRESERVLEVEL > 0
1344 /*
1345 * If some of the reservation's allocated pages remain with
1346 * the original object, then transferring the reservation to
1347 * the new object is neither particularly beneficial nor
1348 * particularly harmful as compared to leaving the reservation
1349 * with the original object. If, however, all of the
1350 * reservation's allocated pages are transferred to the new
1351 * object, then transferring the reservation is typically
1352 * beneficial. Determining which of these two cases applies
1353 * would be more costly than unconditionally renaming the
1354 * reservation.
1355 */
1356 vm_reserv_rename(m, new_object, orig_object, offidxstart);
1357#endif
1358 vm_page_lock(m);
1359 vm_page_rename(m, new_object, idx);
1360 vm_page_unlock(m);
1361 /* page automatically made dirty by rename and cache handled */
1362 vm_page_busy(m);
1363 }
1364 if (orig_object->type == OBJT_SWAP) {
1365 /*
1366 * swap_pager_copy() can sleep, in which case the orig_object's
1367 * and new_object's locks are released and reacquired.
1368 */
1369 swap_pager_copy(orig_object, new_object, offidxstart, 0);
1370
1371 /*
1372 * Transfer any cached pages from orig_object to new_object.
1373 * If swap_pager_copy() found swapped out pages within the
1374 * specified range of orig_object, then it changed
1375 * new_object's type to OBJT_SWAP when it transferred those
1376 * pages to new_object. Otherwise, new_object's type
1377 * should still be OBJT_DEFAULT and orig_object should not
1378 * contain any cached pages within the specified range.
1379 */
1380 if (__predict_false(orig_object->cache != NULL))
1381 vm_page_cache_transfer(orig_object, offidxstart,
1382 new_object);
1383 }
1384 VM_OBJECT_UNLOCK(orig_object);
1385 TAILQ_FOREACH(m, &new_object->memq, listq)
1386 vm_page_wakeup(m);
1387 VM_OBJECT_UNLOCK(new_object);
1388 entry->object.vm_object = new_object;
1389 entry->offset = 0LL;
1390 vm_object_deallocate(orig_object);
1391 VM_OBJECT_LOCK(new_object);
1392}
1393
1394#define OBSC_TEST_ALL_SHADOWED 0x0001
1395#define OBSC_COLLAPSE_NOWAIT 0x0002
1396#define OBSC_COLLAPSE_WAIT 0x0004
1397
1398static int
1399vm_object_backing_scan(vm_object_t object, int op)
1400{
1401 int r = 1;
1402 vm_page_t p;
1403 vm_object_t backing_object;
1404 vm_pindex_t backing_offset_index;
1405
1406 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1407 VM_OBJECT_LOCK_ASSERT(object->backing_object, MA_OWNED);
1408
1409 backing_object = object->backing_object;
1410 backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
1411
1412 /*
1413 * Initial conditions
1414 */
1415 if (op & OBSC_TEST_ALL_SHADOWED) {
1416 /*
1417 * We do not want to have to test for the existence of cache
1418 * or swap pages in the backing object. XXX but with the
1419 * new swapper this would be pretty easy to do.
1420 *
1421 * XXX what about anonymous MAP_SHARED memory that hasn't
1422 * been ZFOD faulted yet? If we do not test for this, the
1423 * shadow test may succeed! XXX
1424 */
1425 if (backing_object->type != OBJT_DEFAULT) {
1426 return (0);
1427 }
1428 }
1429 if (op & OBSC_COLLAPSE_WAIT) {
1430 vm_object_set_flag(backing_object, OBJ_DEAD);
1431 }
1432
1433 /*
1434 * Our scan
1435 */
1436 p = TAILQ_FIRST(&backing_object->memq);
1437 while (p) {
1438 vm_page_t next = TAILQ_NEXT(p, listq);
1439 vm_pindex_t new_pindex = p->pindex - backing_offset_index;
1440
1441 if (op & OBSC_TEST_ALL_SHADOWED) {
1442 vm_page_t pp;
1443
1444 /*
1445 * Ignore pages outside the parent object's range
1446 * and outside the parent object's mapping of the
1447 * backing object.
1448 *
1449 * note that we do not busy the backing object's
1450 * page.
1451 */
1452 if (
1453 p->pindex < backing_offset_index ||
1454 new_pindex >= object->size
1455 ) {
1456 p = next;
1457 continue;
1458 }
1459
1460 /*
1461 * See if the parent has the page or if the parent's
1462 * object pager has the page. If the parent has the
1463 * page but the page is not valid, the parent's
1464 * object pager must have the page.
1465 *
1466 * If this fails, the parent does not completely shadow
1467 * the object and we might as well give up now.
1468 */
1469
1470 pp = vm_page_lookup(object, new_pindex);
1471 if (
1472 (pp == NULL || pp->valid == 0) &&
1473 !vm_pager_has_page(object, new_pindex, NULL, NULL)
1474 ) {
1475 r = 0;
1476 break;
1477 }
1478 }
1479
1480 /*
1481 * Check for busy page
1482 */
1483 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) {
1484 vm_page_t pp;
1485
1486 if (op & OBSC_COLLAPSE_NOWAIT) {
1487 if ((p->oflags & VPO_BUSY) ||
1488 !p->valid ||
1489 p->busy) {
1490 p = next;
1491 continue;
1492 }
1493 } else if (op & OBSC_COLLAPSE_WAIT) {
1494 if ((p->oflags & VPO_BUSY) || p->busy) {
1495 VM_OBJECT_UNLOCK(object);
1496 p->oflags |= VPO_WANTED;
1497 VM_OBJECT_SLEEP(backing_object, p,
1498 PDROP | PVM, "vmocol", 0);
1499 VM_OBJECT_LOCK(object);
1500 VM_OBJECT_LOCK(backing_object);
1501 /*
1502 * If we slept, anything could have
1503 * happened. Since the object is
1504 * marked dead, the backing offset
1505 * should not have changed so we
1506 * just restart our scan.
1507 */
1508 p = TAILQ_FIRST(&backing_object->memq);
1509 continue;
1510 }
1511 }
1512
1513 KASSERT(
1514 p->object == backing_object,
1515 ("vm_object_backing_scan: object mismatch")
1516 );
1517
1518 /*
1519 * Destroy any associated swap
1520 */
1521 if (backing_object->type == OBJT_SWAP) {
1522 swap_pager_freespace(
1523 backing_object,
1524 p->pindex,
1525 1
1526 );
1527 }
1528
1529 if (
1530 p->pindex < backing_offset_index ||
1531 new_pindex >= object->size
1532 ) {
1533 /*
1534 * Page is out of the parent object's range, we
1535 * can simply destroy it.
1536 */
1537 vm_page_lock(p);
1538 KASSERT(!pmap_page_is_mapped(p),
1539 ("freeing mapped page %p", p));
1540 if (p->wire_count == 0)
1541 vm_page_free(p);
1542 else
1543 vm_page_remove(p);
1544 vm_page_unlock(p);
1545 p = next;
1546 continue;
1547 }
1548
1549 pp = vm_page_lookup(object, new_pindex);
1550 if (
1551 (op & OBSC_COLLAPSE_NOWAIT) != 0 &&
1552 (pp != NULL && pp->valid == 0)
1553 ) {
1554 /*
1555 * The page in the parent is not (yet) valid.
1556 * We don't know anything about the state of
1557 * the original page. It might be mapped,
1558 * so we must avoid the next if here.
1559 *
1560 * This is due to a race in vm_fault() where
1561 * we must unbusy the original (backing_obj)
1562 * page before we can (re)lock the parent.
1563 * Hence we can get here.
1564 */
1565 p = next;
1566 continue;
1567 }
1568 if (
1569 pp != NULL ||
1570 vm_pager_has_page(object, new_pindex, NULL, NULL)
1571 ) {
1572 /*
1573 * page already exists in parent OR swap exists
1574 * for this location in the parent. Destroy
1575 * the original page from the backing object.
1576 *
1577 * Leave the parent's page alone
1578 */
1579 vm_page_lock(p);
1580 KASSERT(!pmap_page_is_mapped(p),
1581 ("freeing mapped page %p", p));
1582 if (p->wire_count == 0)
1583 vm_page_free(p);
1584 else
1585 vm_page_remove(p);
1586 vm_page_unlock(p);
1587 p = next;
1588 continue;
1589 }
1590
1591#if VM_NRESERVLEVEL > 0
1592 /*
1593 * Rename the reservation.
1594 */
1595 vm_reserv_rename(p, object, backing_object,
1596 backing_offset_index);
1597#endif
1598
1599 /*
1600 * Page does not exist in parent, rename the
1601 * page from the backing object to the main object.
1602 *
1603 * If the page was mapped to a process, it can remain
1604 * mapped through the rename.
1605 */
1606 vm_page_lock(p);
1607 vm_page_rename(p, object, new_pindex);
1608 vm_page_unlock(p);
1609 /* page automatically made dirty by rename */
1610 }
1611 p = next;
1612 }
1613 return (r);
1614}
1615
1616
1617/*
1618 * this version of collapse allows the operation to occur earlier and
1619 * when paging_in_progress is true for an object... This is not a complete
1620 * operation, but should plug 99.9% of the rest of the leaks.
1621 */
1622static void
1623vm_object_qcollapse(vm_object_t object)
1624{
1625 vm_object_t backing_object = object->backing_object;
1626
1627 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1628 VM_OBJECT_LOCK_ASSERT(backing_object, MA_OWNED);
1629
1630 if (backing_object->ref_count != 1)
1631 return;
1632
1633 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT);
1634}
1635
1636/*
1637 * vm_object_collapse:
1638 *
1639 * Collapse an object with the object backing it.
1640 * Pages in the backing object are moved into the
1641 * parent, and the backing object is deallocated.
1642 */
1643void
1644vm_object_collapse(vm_object_t object)
1645{
1646 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1647
1648 while (TRUE) {
1649 vm_object_t backing_object;
1650
1651 /*
1652 * Verify that the conditions are right for collapse:
1653 *
1654 * The object exists and the backing object exists.
1655 */
1656 if ((backing_object = object->backing_object) == NULL)
1657 break;
1658
1659 /*
1660 * we check the backing object first, because it is most likely
1661 * not collapsable.
1662 */
1663 VM_OBJECT_LOCK(backing_object);
1664 if (backing_object->handle != NULL ||
1665 (backing_object->type != OBJT_DEFAULT &&
1666 backing_object->type != OBJT_SWAP) ||
1667 (backing_object->flags & OBJ_DEAD) ||
1668 object->handle != NULL ||
1669 (object->type != OBJT_DEFAULT &&
1670 object->type != OBJT_SWAP) ||
1671 (object->flags & OBJ_DEAD)) {
1672 VM_OBJECT_UNLOCK(backing_object);
1673 break;
1674 }
1675
1676 if (
1677 object->paging_in_progress != 0 ||
1678 backing_object->paging_in_progress != 0
1679 ) {
1680 vm_object_qcollapse(object);
1681 VM_OBJECT_UNLOCK(backing_object);
1682 break;
1683 }
1684 /*
1685 * We know that we can either collapse the backing object (if
1686 * the parent is the only reference to it) or (perhaps) have
1687 * the parent bypass the object if the parent happens to shadow
1688 * all the resident pages in the entire backing object.
1689 *
1690 * This is ignoring pager-backed pages such as swap pages.
1691 * vm_object_backing_scan fails the shadowing test in this
1692 * case.
1693 */
1694 if (backing_object->ref_count == 1) {
1695 /*
1696 * If there is exactly one reference to the backing
1697 * object, we can collapse it into the parent.
1698 */
1699 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT);
1700
1701#if VM_NRESERVLEVEL > 0
1702 /*
1703 * Break any reservations from backing_object.
1704 */
1705 if (__predict_false(!LIST_EMPTY(&backing_object->rvq)))
1706 vm_reserv_break_all(backing_object);
1707#endif
1708
1709 /*
1710 * Move the pager from backing_object to object.
1711 */
1712 if (backing_object->type == OBJT_SWAP) {
1713 /*
1714 * swap_pager_copy() can sleep, in which case
1715 * the backing_object's and object's locks are
1716 * released and reacquired.
1717 * Since swap_pager_copy() is being asked to
1718 * destroy the source, it will change the
1719 * backing_object's type to OBJT_DEFAULT.
1720 */
1721 swap_pager_copy(
1722 backing_object,
1723 object,
1724 OFF_TO_IDX(object->backing_object_offset), TRUE);
1725
1726 /*
1727 * Free any cached pages from backing_object.
1728 */
1729 if (__predict_false(backing_object->cache != NULL))
1730 vm_page_cache_free(backing_object, 0, 0);
1731 }
1732 /*
1733 * Object now shadows whatever backing_object did.
1734 * Note that the reference to
1735 * backing_object->backing_object moves from within
1736 * backing_object to within object.
1737 */
1738 LIST_REMOVE(object, shadow_list);
1739 backing_object->shadow_count--;
1740 if (backing_object->backing_object) {
1741 VM_OBJECT_LOCK(backing_object->backing_object);
1742 LIST_REMOVE(backing_object, shadow_list);
1743 LIST_INSERT_HEAD(
1744 &backing_object->backing_object->shadow_head,
1745 object, shadow_list);
1746 /*
1747 * The shadow_count has not changed.
1748 */
1749 VM_OBJECT_UNLOCK(backing_object->backing_object);
1750 }
1751 object->backing_object = backing_object->backing_object;
1752 object->backing_object_offset +=
1753 backing_object->backing_object_offset;
1754
1755 /*
1756 * Discard backing_object.
1757 *
1758 * Since the backing object has no pages, no pager left,
1759 * and no object references within it, all that is
1760 * necessary is to dispose of it.
1761 */
1762 KASSERT(backing_object->ref_count == 1, (
1763"backing_object %p was somehow re-referenced during collapse!",
1764 backing_object));
1765 VM_OBJECT_UNLOCK(backing_object);
1766 vm_object_destroy(backing_object);
1767
1768 object_collapses++;
1769 } else {
1770 vm_object_t new_backing_object;
1771
1772 /*
1773 * If we do not entirely shadow the backing object,
1774 * there is nothing we can do so we give up.
1775 */
1776 if (object->resident_page_count != object->size &&
1777 vm_object_backing_scan(object,
1778 OBSC_TEST_ALL_SHADOWED) == 0) {
1779 VM_OBJECT_UNLOCK(backing_object);
1780 break;
1781 }
1782
1783 /*
1784 * Make the parent shadow the next object in the
1785 * chain. Deallocating backing_object will not remove
1786 * it, since its reference count is at least 2.
1787 */
1788 LIST_REMOVE(object, shadow_list);
1789 backing_object->shadow_count--;
1790
1791 new_backing_object = backing_object->backing_object;
1792 if ((object->backing_object = new_backing_object) != NULL) {
1793 VM_OBJECT_LOCK(new_backing_object);
1794 LIST_INSERT_HEAD(
1795 &new_backing_object->shadow_head,
1796 object,
1797 shadow_list
1798 );
1799 new_backing_object->shadow_count++;
1800 vm_object_reference_locked(new_backing_object);
1801 VM_OBJECT_UNLOCK(new_backing_object);
1802 object->backing_object_offset +=
1803 backing_object->backing_object_offset;
1804 }
1805
1806 /*
1807 * Drop the reference count on backing_object. Since
1808 * its ref_count was at least 2, it will not vanish.
1809 */
1810 backing_object->ref_count--;
1811 VM_OBJECT_UNLOCK(backing_object);
1812 object_bypasses++;
1813 }
1814
1815 /*
1816 * Try again with this object's new backing object.
1817 */
1818 }
1819}
1820
1821/*
1822 * vm_object_page_remove:
1823 *
1824 * For the given object, either frees or invalidates each of the
1825 * specified pages. In general, a page is freed. However, if a page is
1826 * wired for any reason other than the existence of a managed, wired
1827 * mapping, then it may be invalidated but not removed from the object.
1828 * Pages are specified by the given range ["start", "end") and the option
1829 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range
1830 * extends from "start" to the end of the object. If the option
1831 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the
1832 * specified range are affected. If the option OBJPR_NOTMAPPED is
1833 * specified, then the pages within the specified range must have no
1834 * mappings. Otherwise, if this option is not specified, any mappings to
1835 * the specified pages are removed before the pages are freed or
1836 * invalidated.
1837 *
1838 * In general, this operation should only be performed on objects that
1839 * contain managed pages. There are, however, two exceptions. First, it
1840 * is performed on the kernel and kmem objects by vm_map_entry_delete().
1841 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device-
1842 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must
1843 * not be specified and the option OBJPR_NOTMAPPED must be specified.
1844 *
1845 * The object must be locked.
1846 */
1847void
1848vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
1849 int options)
1850{
1851 vm_page_t p, next;
1852 int wirings;
1853
1854 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1855 KASSERT((object->flags & OBJ_UNMANAGED) == 0 ||
1856 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED,
1857 ("vm_object_page_remove: illegal options for object %p", object));
1858 if (object->resident_page_count == 0)
1859 goto skipmemq;
1860 vm_object_pip_add(object, 1);
1861again:
1862 p = vm_page_find_least(object, start);
1863
1864 /*
1865 * Here, the variable "p" is either (1) the page with the least pindex
1866 * greater than or equal to the parameter "start" or (2) NULL.
1867 */
1868 for (; p != NULL && (p->pindex < end || end == 0); p = next) {
1869 next = TAILQ_NEXT(p, listq);
1870
1871 /*
1872 * If the page is wired for any reason besides the existence
1873 * of managed, wired mappings, then it cannot be freed. For
1874 * example, fictitious pages, which represent device memory,
1875 * are inherently wired and cannot be freed. They can,
1876 * however, be invalidated if the option OBJPR_CLEANONLY is
1877 * not specified.
1878 */
1879 vm_page_lock(p);
1880 if ((wirings = p->wire_count) != 0 &&
1881 (wirings = pmap_page_wired_mappings(p)) != p->wire_count) {
1882 if ((options & OBJPR_NOTMAPPED) == 0) {
1883 pmap_remove_all(p);
1884 /* Account for removal of wired mappings. */
1885 if (wirings != 0)
1886 p->wire_count -= wirings;
1887 }
1888 if ((options & OBJPR_CLEANONLY) == 0) {
1889 p->valid = 0;
1890 vm_page_undirty(p);
1891 }
1892 vm_page_unlock(p);
1893 continue;
1894 }
1895 if (vm_page_sleep_if_busy(p, TRUE, "vmopar"))
1896 goto again;
1897 KASSERT((p->flags & PG_FICTITIOUS) == 0,
1898 ("vm_object_page_remove: page %p is fictitious", p));
1899 if ((options & OBJPR_CLEANONLY) != 0 && p->valid != 0) {
1900 if ((options & OBJPR_NOTMAPPED) == 0)
1901 pmap_remove_write(p);
1902 if (p->dirty) {
1903 vm_page_unlock(p);
1904 continue;
1905 }
1906 }
1907 if ((options & OBJPR_NOTMAPPED) == 0) {
1908 pmap_remove_all(p);
1909 /* Account for removal of wired mappings. */
1910 if (wirings != 0) {
1911 KASSERT(p->wire_count == wirings,
1912 ("inconsistent wire count %d %d %p",
1913 p->wire_count, wirings, p));
1914 p->wire_count = 0;
1915 atomic_subtract_int(&cnt.v_wire_count, 1);
1916 }
1917 }
1918 vm_page_free(p);
1919 vm_page_unlock(p);
1920 }
1921 vm_object_pip_wakeup(object);
1922skipmemq:
1923 if (__predict_false(object->cache != NULL))
1924 vm_page_cache_free(object, start, end);
1925}
1926
1927/*
1928 * vm_object_page_cache:
1929 *
1930 * For the given object, attempt to move the specified clean
1931 * pages to the cache queue. If a page is wired for any reason,
1932 * then it will not be changed. Pages are specified by the given
1933 * range ["start", "end"). As a special case, if "end" is zero,
1934 * then the range extends from "start" to the end of the object.
1935 * Any mappings to the specified pages are removed before the
1936 * pages are moved to the cache queue.
1937 *
1938 * This operation should only be performed on objects that
1939 * contain non-fictitious, managed pages.
1940 *
1941 * The object must be locked.
1942 */
1943void
1944vm_object_page_cache(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
1945{
1946 struct mtx *mtx, *new_mtx;
1947 vm_page_t p, next;
1948
1949 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1950 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0,
1951 ("vm_object_page_cache: illegal object %p", object));
1952 if (object->resident_page_count == 0)
1953 return;
1954 p = vm_page_find_least(object, start);
1955
1956 /*
1957 * Here, the variable "p" is either (1) the page with the least pindex
1958 * greater than or equal to the parameter "start" or (2) NULL.
1959 */
1960 mtx = NULL;
1961 for (; p != NULL && (p->pindex < end || end == 0); p = next) {
1962 next = TAILQ_NEXT(p, listq);
1963
1964 /*
1965 * Avoid releasing and reacquiring the same page lock.
1966 */
1967 new_mtx = vm_page_lockptr(p);
1968 if (mtx != new_mtx) {
1969 if (mtx != NULL)
1970 mtx_unlock(mtx);
1971 mtx = new_mtx;
1972 mtx_lock(mtx);
1973 }
1974 vm_page_try_to_cache(p);
1975 }
1976 if (mtx != NULL)
1977 mtx_unlock(mtx);
1978}
1979
1980/*
1981 * Populate the specified range of the object with valid pages. Returns
1982 * TRUE if the range is successfully populated and FALSE otherwise.
1983 *
1984 * Note: This function should be optimized to pass a larger array of
1985 * pages to vm_pager_get_pages() before it is applied to a non-
1986 * OBJT_DEVICE object.
1987 *
1988 * The object must be locked.
1989 */
1990boolean_t
1991vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
1992{
1993 vm_page_t m, ma[1];
1994 vm_pindex_t pindex;
1995 int rv;
1996
1997 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1998 for (pindex = start; pindex < end; pindex++) {
1999 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL |
2000 VM_ALLOC_RETRY);
2001 if (m->valid != VM_PAGE_BITS_ALL) {
2002 ma[0] = m;
2003 rv = vm_pager_get_pages(object, ma, 1, 0);
2004 m = vm_page_lookup(object, pindex);
2005 if (m == NULL)
2006 break;
2007 if (rv != VM_PAGER_OK) {
2008 vm_page_lock(m);
2009 vm_page_free(m);
2010 vm_page_unlock(m);
2011 break;
2012 }
2013 }
2014 /*
2015 * Keep "m" busy because a subsequent iteration may unlock
2016 * the object.
2017 */
2018 }
2019 if (pindex > start) {
2020 m = vm_page_lookup(object, start);
2021 while (m != NULL && m->pindex < pindex) {
2022 vm_page_wakeup(m);
2023 m = TAILQ_NEXT(m, listq);
2024 }
2025 }
2026 return (pindex == end);
2027}
2028
2029/*
2030 * Routine: vm_object_coalesce
2031 * Function: Coalesces two objects backing up adjoining
2032 * regions of memory into a single object.
2033 *
2034 * returns TRUE if objects were combined.
2035 *
2036 * NOTE: Only works at the moment if the second object is NULL -
2037 * if it's not, which object do we lock first?
2038 *
2039 * Parameters:
2040 * prev_object First object to coalesce
2041 * prev_offset Offset into prev_object
2042 * prev_size Size of reference to prev_object
2043 * next_size Size of reference to the second object
2044 * reserved Indicator that extension region has
2045 * swap accounted for
2046 *
2047 * Conditions:
2048 * The object must *not* be locked.
2049 */
2050boolean_t
2051vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset,
2052 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved)
2053{
2054 vm_pindex_t next_pindex;
2055
2056 if (prev_object == NULL)
2057 return (TRUE);
2058 VM_OBJECT_LOCK(prev_object);
2059 if (prev_object->type != OBJT_DEFAULT &&
2060 prev_object->type != OBJT_SWAP) {
2061 VM_OBJECT_UNLOCK(prev_object);
2062 return (FALSE);
2063 }
2064
2065 /*
2066 * Try to collapse the object first
2067 */
2068 vm_object_collapse(prev_object);
2069
2070 /*
2071 * Can't coalesce if: . more than one reference . paged out . shadows
2072 * another object . has a copy elsewhere (any of which mean that the
2073 * pages not mapped to prev_entry may be in use anyway)
2074 */
2075 if (prev_object->backing_object != NULL) {
2076 VM_OBJECT_UNLOCK(prev_object);
2077 return (FALSE);
2078 }
2079
2080 prev_size >>= PAGE_SHIFT;
2081 next_size >>= PAGE_SHIFT;
2082 next_pindex = OFF_TO_IDX(prev_offset) + prev_size;
2083
2084 if ((prev_object->ref_count > 1) &&
2085 (prev_object->size != next_pindex)) {
2086 VM_OBJECT_UNLOCK(prev_object);
2087 return (FALSE);
2088 }
2089
2090 /*
2091 * Account for the charge.
2092 */
2093 if (prev_object->cred != NULL) {
2094
2095 /*
2096 * If prev_object was charged, then this mapping,
2097 * althought not charged now, may become writable
2098 * later. Non-NULL cred in the object would prevent
2099 * swap reservation during enabling of the write
2100 * access, so reserve swap now. Failed reservation
2101 * cause allocation of the separate object for the map
2102 * entry, and swap reservation for this entry is
2103 * managed in appropriate time.
2104 */
2105 if (!reserved && !swap_reserve_by_cred(ptoa(next_size),
2106 prev_object->cred)) {
2107 return (FALSE);
2108 }
2109 prev_object->charge += ptoa(next_size);
2110 }
2111
2112 /*
2113 * Remove any pages that may still be in the object from a previous
2114 * deallocation.
2115 */
2116 if (next_pindex < prev_object->size) {
2117 vm_object_page_remove(prev_object, next_pindex, next_pindex +
2118 next_size, 0);
2119 if (prev_object->type == OBJT_SWAP)
2120 swap_pager_freespace(prev_object,
2121 next_pindex, next_size);
2122#if 0
2123 if (prev_object->cred != NULL) {
2124 KASSERT(prev_object->charge >=
2125 ptoa(prev_object->size - next_pindex),
2126 ("object %p overcharged 1 %jx %jx", prev_object,
2127 (uintmax_t)next_pindex, (uintmax_t)next_size));
2128 prev_object->charge -= ptoa(prev_object->size -
2129 next_pindex);
2130 }
2131#endif
2132 }
2133
2134 /*
2135 * Extend the object if necessary.
2136 */
2137 if (next_pindex + next_size > prev_object->size)
2138 prev_object->size = next_pindex + next_size;
2139
2140 VM_OBJECT_UNLOCK(prev_object);
2141 return (TRUE);
2142}
2143
2144void
2145vm_object_set_writeable_dirty(vm_object_t object)
2146{
2147
2148 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
2149 if (object->type != OBJT_VNODE)
2150 return;
2151 object->generation++;
2152 if ((object->flags & OBJ_MIGHTBEDIRTY) != 0)
2153 return;
2154 vm_object_set_flag(object, OBJ_MIGHTBEDIRTY);
2155}
2156
2157#include "opt_ddb.h"
2158#ifdef DDB
2159#include <sys/kernel.h>
2160
2161#include <sys/cons.h>
2162
2163#include <ddb/ddb.h>
2164
2165static int
2166_vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry)
2167{
2168 vm_map_t tmpm;
2169 vm_map_entry_t tmpe;
2170 vm_object_t obj;
2171 int entcount;
2172
2173 if (map == 0)
2174 return 0;
2175
2176 if (entry == 0) {
2177 tmpe = map->header.next;
2178 entcount = map->nentries;
2179 while (entcount-- && (tmpe != &map->header)) {
2180 if (_vm_object_in_map(map, object, tmpe)) {
2181 return 1;
2182 }
2183 tmpe = tmpe->next;
2184 }
2185 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
2186 tmpm = entry->object.sub_map;
2187 tmpe = tmpm->header.next;
2188 entcount = tmpm->nentries;
2189 while (entcount-- && tmpe != &tmpm->header) {
2190 if (_vm_object_in_map(tmpm, object, tmpe)) {
2191 return 1;
2192 }
2193 tmpe = tmpe->next;
2194 }
2195 } else if ((obj = entry->object.vm_object) != NULL) {
2196 for (; obj; obj = obj->backing_object)
2197 if (obj == object) {
2198 return 1;
2199 }
2200 }
2201 return 0;
2202}
2203
2204static int
2205vm_object_in_map(vm_object_t object)
2206{
2207 struct proc *p;
2208
2209 /* sx_slock(&allproc_lock); */
2210 FOREACH_PROC_IN_SYSTEM(p) {
2211 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */)
2212 continue;
2213 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) {
2214 /* sx_sunlock(&allproc_lock); */
2215 return 1;
2216 }
2217 }
2218 /* sx_sunlock(&allproc_lock); */
2219 if (_vm_object_in_map(kernel_map, object, 0))
2220 return 1;
2221 if (_vm_object_in_map(kmem_map, object, 0))
2222 return 1;
2223 if (_vm_object_in_map(pager_map, object, 0))
2224 return 1;
2225 if (_vm_object_in_map(buffer_map, object, 0))
2226 return 1;
2227 return 0;
2228}
2229
2230DB_SHOW_COMMAND(vmochk, vm_object_check)
2231{
2232 vm_object_t object;
2233
2234 /*
2235 * make sure that internal objs are in a map somewhere
2236 * and none have zero ref counts.
2237 */
2238 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2239 if (object->handle == NULL &&
2240 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
2241 if (object->ref_count == 0) {
2242 db_printf("vmochk: internal obj has zero ref count: %ld\n",
2243 (long)object->size);
2244 }
2245 if (!vm_object_in_map(object)) {
2246 db_printf(
2247 "vmochk: internal obj is not in a map: "
2248 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n",
2249 object->ref_count, (u_long)object->size,
2250 (u_long)object->size,
2251 (void *)object->backing_object);
2252 }
2253 }
2254 }
2255}
2256
2257/*
2258 * vm_object_print: [ debug ]
2259 */
2260DB_SHOW_COMMAND(object, vm_object_print_static)
2261{
2262 /* XXX convert args. */
2263 vm_object_t object = (vm_object_t)addr;
2264 boolean_t full = have_addr;
2265
2266 vm_page_t p;
2267
2268 /* XXX count is an (unused) arg. Avoid shadowing it. */
2269#define count was_count
2270
2271 int count;
2272
2273 if (object == NULL)
2274 return;
2275
2276 db_iprintf(
2277 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n",
2278 object, (int)object->type, (uintmax_t)object->size,
2279 object->resident_page_count, object->ref_count, object->flags,
2280 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge);
2281 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n",
2282 object->shadow_count,
2283 object->backing_object ? object->backing_object->ref_count : 0,
2284 object->backing_object, (uintmax_t)object->backing_object_offset);
2285
2286 if (!full)
2287 return;
2288
2289 db_indent += 2;
2290 count = 0;
2291 TAILQ_FOREACH(p, &object->memq, listq) {
2292 if (count == 0)
2293 db_iprintf("memory:=");
2294 else if (count == 6) {
2295 db_printf("\n");
2296 db_iprintf(" ...");
2297 count = 0;
2298 } else
2299 db_printf(",");
2300 count++;
2301
2302 db_printf("(off=0x%jx,page=0x%jx)",
2303 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p));
2304 }
2305 if (count != 0)
2306 db_printf("\n");
2307 db_indent -= 2;
2308}
2309
2310/* XXX. */
2311#undef count
2312
2313/* XXX need this non-static entry for calling from vm_map_print. */
2314void
2315vm_object_print(
2316 /* db_expr_t */ long addr,
2317 boolean_t have_addr,
2318 /* db_expr_t */ long count,
2319 char *modif)
2320{
2321 vm_object_print_static(addr, have_addr, count, modif);
2322}
2323
2324DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
2325{
2326 vm_object_t object;
2327 vm_pindex_t fidx;
2328 vm_paddr_t pa;
2329 vm_page_t m, prev_m;
2330 int rcount, nl, c;
2331
2332 nl = 0;
2333 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2334 db_printf("new object: %p\n", (void *)object);
2335 if (nl > 18) {
2336 c = cngetc();
2337 if (c != ' ')
2338 return;
2339 nl = 0;
2340 }
2341 nl++;
2342 rcount = 0;
2343 fidx = 0;
2344 pa = -1;
2345 TAILQ_FOREACH(m, &object->memq, listq) {
2346 if (m->pindex > 128)
2347 break;
2348 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL &&
2349 prev_m->pindex + 1 != m->pindex) {
2350 if (rcount) {
2351 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2352 (long)fidx, rcount, (long)pa);
2353 if (nl > 18) {
2354 c = cngetc();
2355 if (c != ' ')
2356 return;
2357 nl = 0;
2358 }
2359 nl++;
2360 rcount = 0;
2361 }
2362 }
2363 if (rcount &&
2364 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) {
2365 ++rcount;
2366 continue;
2367 }
2368 if (rcount) {
2369 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2370 (long)fidx, rcount, (long)pa);
2371 if (nl > 18) {
2372 c = cngetc();
2373 if (c != ' ')
2374 return;
2375 nl = 0;
2376 }
2377 nl++;
2378 }
2379 fidx = m->pindex;
2380 pa = VM_PAGE_TO_PHYS(m);
2381 rcount = 1;
2382 }
2383 if (rcount) {
2384 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2385 (long)fidx, rcount, (long)pa);
2386 if (nl > 18) {
2387 c = cngetc();
2388 if (c != ' ')
2389 return;
2390 nl = 0;
2391 }
2392 nl++;
2393 }
2394 }
2395}
2396#endif /* DDB */
| 278 _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
279 kmem_object);
280#if VM_NRESERVLEVEL > 0
281 kmem_object->flags |= OBJ_COLORED;
282 kmem_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS);
283#endif
284
285 /*
286 * The lock portion of struct vm_object must be type stable due
287 * to vm_pageout_fallback_object_lock locking a vm object
288 * without holding any references to it.
289 */
290 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL,
291#ifdef INVARIANTS
292 vm_object_zdtor,
293#else
294 NULL,
295#endif
296 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM|UMA_ZONE_NOFREE);
297}
298
299void
300vm_object_clear_flag(vm_object_t object, u_short bits)
301{
302
303 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
304 object->flags &= ~bits;
305}
306
307/*
308 * Sets the default memory attribute for the specified object. Pages
309 * that are allocated to this object are by default assigned this memory
310 * attribute.
311 *
312 * Presently, this function must be called before any pages are allocated
313 * to the object. In the future, this requirement may be relaxed for
314 * "default" and "swap" objects.
315 */
316int
317vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr)
318{
319
320 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
321 switch (object->type) {
322 case OBJT_DEFAULT:
323 case OBJT_DEVICE:
324 case OBJT_MGTDEVICE:
325 case OBJT_PHYS:
326 case OBJT_SG:
327 case OBJT_SWAP:
328 case OBJT_VNODE:
329 if (!TAILQ_EMPTY(&object->memq))
330 return (KERN_FAILURE);
331 break;
332 case OBJT_DEAD:
333 return (KERN_INVALID_ARGUMENT);
334 default:
335 panic("vm_object_set_memattr: object %p is of undefined type",
336 object);
337 }
338 object->memattr = memattr;
339 return (KERN_SUCCESS);
340}
341
342void
343vm_object_pip_add(vm_object_t object, short i)
344{
345
346 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
347 object->paging_in_progress += i;
348}
349
350void
351vm_object_pip_subtract(vm_object_t object, short i)
352{
353
354 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
355 object->paging_in_progress -= i;
356}
357
358void
359vm_object_pip_wakeup(vm_object_t object)
360{
361
362 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
363 object->paging_in_progress--;
364 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
365 vm_object_clear_flag(object, OBJ_PIPWNT);
366 wakeup(object);
367 }
368}
369
370void
371vm_object_pip_wakeupn(vm_object_t object, short i)
372{
373
374 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
375 if (i)
376 object->paging_in_progress -= i;
377 if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) {
378 vm_object_clear_flag(object, OBJ_PIPWNT);
379 wakeup(object);
380 }
381}
382
383void
384vm_object_pip_wait(vm_object_t object, char *waitid)
385{
386
387 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
388 while (object->paging_in_progress) {
389 object->flags |= OBJ_PIPWNT;
390 VM_OBJECT_SLEEP(object, object, PVM, waitid, 0);
391 }
392}
393
394/*
395 * vm_object_allocate:
396 *
397 * Returns a new object with the given size.
398 */
399vm_object_t
400vm_object_allocate(objtype_t type, vm_pindex_t size)
401{
402 vm_object_t object;
403
404 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK);
405 _vm_object_allocate(type, size, object);
406 return (object);
407}
408
409
410/*
411 * vm_object_reference:
412 *
413 * Gets another reference to the given object. Note: OBJ_DEAD
414 * objects can be referenced during final cleaning.
415 */
416void
417vm_object_reference(vm_object_t object)
418{
419 if (object == NULL)
420 return;
421 VM_OBJECT_LOCK(object);
422 vm_object_reference_locked(object);
423 VM_OBJECT_UNLOCK(object);
424}
425
426/*
427 * vm_object_reference_locked:
428 *
429 * Gets another reference to the given object.
430 *
431 * The object must be locked.
432 */
433void
434vm_object_reference_locked(vm_object_t object)
435{
436 struct vnode *vp;
437
438 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
439 object->ref_count++;
440 if (object->type == OBJT_VNODE) {
441 vp = object->handle;
442 vref(vp);
443 }
444}
445
446/*
447 * Handle deallocating an object of type OBJT_VNODE.
448 */
449static void
450vm_object_vndeallocate(vm_object_t object)
451{
452 struct vnode *vp = (struct vnode *) object->handle;
453
454 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
455 KASSERT(object->type == OBJT_VNODE,
456 ("vm_object_vndeallocate: not a vnode object"));
457 KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp"));
458#ifdef INVARIANTS
459 if (object->ref_count == 0) {
460 vprint("vm_object_vndeallocate", vp);
461 panic("vm_object_vndeallocate: bad object reference count");
462 }
463#endif
464
465 if (object->ref_count > 1) {
466 object->ref_count--;
467 VM_OBJECT_UNLOCK(object);
468 /* vrele may need the vnode lock. */
469 vrele(vp);
470 } else {
471 vhold(vp);
472 VM_OBJECT_UNLOCK(object);
473 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
474 vdrop(vp);
475 VM_OBJECT_LOCK(object);
476 object->ref_count--;
477 if (object->type == OBJT_DEAD) {
478 VM_OBJECT_UNLOCK(object);
479 VOP_UNLOCK(vp, 0);
480 } else {
481 if (object->ref_count == 0)
482 VOP_UNSET_TEXT(vp);
483 VM_OBJECT_UNLOCK(object);
484 vput(vp);
485 }
486 }
487}
488
489/*
490 * vm_object_deallocate:
491 *
492 * Release a reference to the specified object,
493 * gained either through a vm_object_allocate
494 * or a vm_object_reference call. When all references
495 * are gone, storage associated with this object
496 * may be relinquished.
497 *
498 * No object may be locked.
499 */
500void
501vm_object_deallocate(vm_object_t object)
502{
503 vm_object_t temp;
504
505 while (object != NULL) {
506 VM_OBJECT_LOCK(object);
507 if (object->type == OBJT_VNODE) {
508 vm_object_vndeallocate(object);
509 return;
510 }
511
512 KASSERT(object->ref_count != 0,
513 ("vm_object_deallocate: object deallocated too many times: %d", object->type));
514
515 /*
516 * If the reference count goes to 0 we start calling
517 * vm_object_terminate() on the object chain.
518 * A ref count of 1 may be a special case depending on the
519 * shadow count being 0 or 1.
520 */
521 object->ref_count--;
522 if (object->ref_count > 1) {
523 VM_OBJECT_UNLOCK(object);
524 return;
525 } else if (object->ref_count == 1) {
526 if (object->shadow_count == 0 &&
527 object->handle == NULL &&
528 (object->type == OBJT_DEFAULT ||
529 object->type == OBJT_SWAP)) {
530 vm_object_set_flag(object, OBJ_ONEMAPPING);
531 } else if ((object->shadow_count == 1) &&
532 (object->handle == NULL) &&
533 (object->type == OBJT_DEFAULT ||
534 object->type == OBJT_SWAP)) {
535 vm_object_t robject;
536
537 robject = LIST_FIRST(&object->shadow_head);
538 KASSERT(robject != NULL,
539 ("vm_object_deallocate: ref_count: %d, shadow_count: %d",
540 object->ref_count,
541 object->shadow_count));
542 if (!VM_OBJECT_TRYLOCK(robject)) {
543 /*
544 * Avoid a potential deadlock.
545 */
546 object->ref_count++;
547 VM_OBJECT_UNLOCK(object);
548 /*
549 * More likely than not the thread
550 * holding robject's lock has lower
551 * priority than the current thread.
552 * Let the lower priority thread run.
553 */
554 pause("vmo_de", 1);
555 continue;
556 }
557 /*
558 * Collapse object into its shadow unless its
559 * shadow is dead. In that case, object will
560 * be deallocated by the thread that is
561 * deallocating its shadow.
562 */
563 if ((robject->flags & OBJ_DEAD) == 0 &&
564 (robject->handle == NULL) &&
565 (robject->type == OBJT_DEFAULT ||
566 robject->type == OBJT_SWAP)) {
567
568 robject->ref_count++;
569retry:
570 if (robject->paging_in_progress) {
571 VM_OBJECT_UNLOCK(object);
572 vm_object_pip_wait(robject,
573 "objde1");
574 temp = robject->backing_object;
575 if (object == temp) {
576 VM_OBJECT_LOCK(object);
577 goto retry;
578 }
579 } else if (object->paging_in_progress) {
580 VM_OBJECT_UNLOCK(robject);
581 object->flags |= OBJ_PIPWNT;
582 VM_OBJECT_SLEEP(object, object,
583 PDROP | PVM, "objde2", 0);
584 VM_OBJECT_LOCK(robject);
585 temp = robject->backing_object;
586 if (object == temp) {
587 VM_OBJECT_LOCK(object);
588 goto retry;
589 }
590 } else
591 VM_OBJECT_UNLOCK(object);
592
593 if (robject->ref_count == 1) {
594 robject->ref_count--;
595 object = robject;
596 goto doterm;
597 }
598 object = robject;
599 vm_object_collapse(object);
600 VM_OBJECT_UNLOCK(object);
601 continue;
602 }
603 VM_OBJECT_UNLOCK(robject);
604 }
605 VM_OBJECT_UNLOCK(object);
606 return;
607 }
608doterm:
609 temp = object->backing_object;
610 if (temp != NULL) {
611 VM_OBJECT_LOCK(temp);
612 LIST_REMOVE(object, shadow_list);
613 temp->shadow_count--;
614 VM_OBJECT_UNLOCK(temp);
615 object->backing_object = NULL;
616 }
617 /*
618 * Don't double-terminate, we could be in a termination
619 * recursion due to the terminate having to sync data
620 * to disk.
621 */
622 if ((object->flags & OBJ_DEAD) == 0)
623 vm_object_terminate(object);
624 else
625 VM_OBJECT_UNLOCK(object);
626 object = temp;
627 }
628}
629
630/*
631 * vm_object_destroy removes the object from the global object list
632 * and frees the space for the object.
633 */
634void
635vm_object_destroy(vm_object_t object)
636{
637
638 /*
639 * Remove the object from the global object list.
640 */
641 mtx_lock(&vm_object_list_mtx);
642 TAILQ_REMOVE(&vm_object_list, object, object_list);
643 mtx_unlock(&vm_object_list_mtx);
644
645 /*
646 * Release the allocation charge.
647 */
648 if (object->cred != NULL) {
649 KASSERT(object->type == OBJT_DEFAULT ||
650 object->type == OBJT_SWAP,
651 ("vm_object_terminate: non-swap obj %p has cred",
652 object));
653 swap_release_by_cred(object->charge, object->cred);
654 object->charge = 0;
655 crfree(object->cred);
656 object->cred = NULL;
657 }
658
659 /*
660 * Free the space for the object.
661 */
662 uma_zfree(obj_zone, object);
663}
664
665/*
666 * vm_object_terminate actually destroys the specified object, freeing
667 * up all previously used resources.
668 *
669 * The object must be locked.
670 * This routine may block.
671 */
672void
673vm_object_terminate(vm_object_t object)
674{
675 vm_page_t p, p_next;
676
677 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
678
679 /*
680 * Make sure no one uses us.
681 */
682 vm_object_set_flag(object, OBJ_DEAD);
683
684 /*
685 * wait for the pageout daemon to be done with the object
686 */
687 vm_object_pip_wait(object, "objtrm");
688
689 KASSERT(!object->paging_in_progress,
690 ("vm_object_terminate: pageout in progress"));
691
692 /*
693 * Clean and free the pages, as appropriate. All references to the
694 * object are gone, so we don't need to lock it.
695 */
696 if (object->type == OBJT_VNODE) {
697 struct vnode *vp = (struct vnode *)object->handle;
698
699 /*
700 * Clean pages and flush buffers.
701 */
702 vm_object_page_clean(object, 0, 0, OBJPC_SYNC);
703 VM_OBJECT_UNLOCK(object);
704
705 vinvalbuf(vp, V_SAVE, 0, 0);
706
707 VM_OBJECT_LOCK(object);
708 }
709
710 KASSERT(object->ref_count == 0,
711 ("vm_object_terminate: object with references, ref_count=%d",
712 object->ref_count));
713
714 /*
715 * Free any remaining pageable pages. This also removes them from the
716 * paging queues. However, don't free wired pages, just remove them
717 * from the object. Rather than incrementally removing each page from
718 * the object, the page and object are reset to any empty state.
719 */
720 TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) {
721 KASSERT(!p->busy && (p->oflags & VPO_BUSY) == 0,
722 ("vm_object_terminate: freeing busy page %p", p));
723 vm_page_lock(p);
724 /*
725 * Optimize the page's removal from the object by resetting
726 * its "object" field. Specifically, if the page is not
727 * wired, then the effect of this assignment is that
728 * vm_page_free()'s call to vm_page_remove() will return
729 * immediately without modifying the page or the object.
730 */
731 p->object = NULL;
732 if (p->wire_count == 0) {
733 vm_page_free(p);
734 PCPU_INC(cnt.v_pfree);
735 }
736 vm_page_unlock(p);
737 }
738 /*
739 * If the object contained any pages, then reset it to an empty state.
740 * None of the object's fields, including "resident_page_count", were
741 * modified by the preceding loop.
742 */
743 if (object->resident_page_count != 0) {
744 object->root = NULL;
745 TAILQ_INIT(&object->memq);
746 object->resident_page_count = 0;
747 if (object->type == OBJT_VNODE)
748 vdrop(object->handle);
749 }
750
751#if VM_NRESERVLEVEL > 0
752 if (__predict_false(!LIST_EMPTY(&object->rvq)))
753 vm_reserv_break_all(object);
754#endif
755 if (__predict_false(object->cache != NULL))
756 vm_page_cache_free(object, 0, 0);
757
758 /*
759 * Let the pager know object is dead.
760 */
761 vm_pager_deallocate(object);
762 VM_OBJECT_UNLOCK(object);
763
764 vm_object_destroy(object);
765}
766
767/*
768 * Make the page read-only so that we can clear the object flags. However, if
769 * this is a nosync mmap then the object is likely to stay dirty so do not
770 * mess with the page and do not clear the object flags. Returns TRUE if the
771 * page should be flushed, and FALSE otherwise.
772 */
773static boolean_t
774vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *clearobjflags)
775{
776
777 /*
778 * If we have been asked to skip nosync pages and this is a
779 * nosync page, skip it. Note that the object flags were not
780 * cleared in this case so we do not have to set them.
781 */
782 if ((flags & OBJPC_NOSYNC) != 0 && (p->oflags & VPO_NOSYNC) != 0) {
783 *clearobjflags = FALSE;
784 return (FALSE);
785 } else {
786 pmap_remove_write(p);
787 return (p->dirty != 0);
788 }
789}
790
791/*
792 * vm_object_page_clean
793 *
794 * Clean all dirty pages in the specified range of object. Leaves page
795 * on whatever queue it is currently on. If NOSYNC is set then do not
796 * write out pages with VPO_NOSYNC set (originally comes from MAP_NOSYNC),
797 * leaving the object dirty.
798 *
799 * When stuffing pages asynchronously, allow clustering. XXX we need a
800 * synchronous clustering mode implementation.
801 *
802 * Odd semantics: if start == end, we clean everything.
803 *
804 * The object must be locked.
805 *
806 * Returns FALSE if some page from the range was not written, as
807 * reported by the pager, and TRUE otherwise.
808 */
809boolean_t
810vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end,
811 int flags)
812{
813 vm_page_t np, p;
814 vm_pindex_t pi, tend, tstart;
815 int curgeneration, n, pagerflags;
816 boolean_t clearobjflags, eio, res;
817
818 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
819 KASSERT(object->type == OBJT_VNODE, ("Not a vnode object"));
820 if ((object->flags & OBJ_MIGHTBEDIRTY) == 0 ||
821 object->resident_page_count == 0)
822 return (TRUE);
823
824 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ?
825 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK;
826 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0;
827
828 tstart = OFF_TO_IDX(start);
829 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK);
830 clearobjflags = tstart == 0 && tend >= object->size;
831 res = TRUE;
832
833rescan:
834 curgeneration = object->generation;
835
836 for (p = vm_page_find_least(object, tstart); p != NULL; p = np) {
837 pi = p->pindex;
838 if (pi >= tend)
839 break;
840 np = TAILQ_NEXT(p, listq);
841 if (p->valid == 0)
842 continue;
843 if (vm_page_sleep_if_busy(p, TRUE, "vpcwai")) {
844 if (object->generation != curgeneration) {
845 if ((flags & OBJPC_SYNC) != 0)
846 goto rescan;
847 else
848 clearobjflags = FALSE;
849 }
850 np = vm_page_find_least(object, pi);
851 continue;
852 }
853 if (!vm_object_page_remove_write(p, flags, &clearobjflags))
854 continue;
855
856 n = vm_object_page_collect_flush(object, p, pagerflags,
857 flags, &clearobjflags, &eio);
858 if (eio) {
859 res = FALSE;
860 clearobjflags = FALSE;
861 }
862 if (object->generation != curgeneration) {
863 if ((flags & OBJPC_SYNC) != 0)
864 goto rescan;
865 else
866 clearobjflags = FALSE;
867 }
868
869 /*
870 * If the VOP_PUTPAGES() did a truncated write, so
871 * that even the first page of the run is not fully
872 * written, vm_pageout_flush() returns 0 as the run
873 * length. Since the condition that caused truncated
874 * write may be permanent, e.g. exhausted free space,
875 * accepting n == 0 would cause an infinite loop.
876 *
877 * Forwarding the iterator leaves the unwritten page
878 * behind, but there is not much we can do there if
879 * filesystem refuses to write it.
880 */
881 if (n == 0) {
882 n = 1;
883 clearobjflags = FALSE;
884 }
885 np = vm_page_find_least(object, pi + n);
886 }
887#if 0
888 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0);
889#endif
890
891 if (clearobjflags)
892 vm_object_clear_flag(object, OBJ_MIGHTBEDIRTY);
893 return (res);
894}
895
896static int
897vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int pagerflags,
898 int flags, boolean_t *clearobjflags, boolean_t *eio)
899{
900 vm_page_t ma[vm_pageout_page_count], p_first, tp;
901 int count, i, mreq, runlen;
902
903 vm_page_lock_assert(p, MA_NOTOWNED);
904 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
905
906 count = 1;
907 mreq = 0;
908
909 for (tp = p; count < vm_pageout_page_count; count++) {
910 tp = vm_page_next(tp);
911 if (tp == NULL || tp->busy != 0 || (tp->oflags & VPO_BUSY) != 0)
912 break;
913 if (!vm_object_page_remove_write(tp, flags, clearobjflags))
914 break;
915 }
916
917 for (p_first = p; count < vm_pageout_page_count; count++) {
918 tp = vm_page_prev(p_first);
919 if (tp == NULL || tp->busy != 0 || (tp->oflags & VPO_BUSY) != 0)
920 break;
921 if (!vm_object_page_remove_write(tp, flags, clearobjflags))
922 break;
923 p_first = tp;
924 mreq++;
925 }
926
927 for (tp = p_first, i = 0; i < count; tp = TAILQ_NEXT(tp, listq), i++)
928 ma[i] = tp;
929
930 vm_pageout_flush(ma, count, pagerflags, mreq, &runlen, eio);
931 return (runlen);
932}
933
934/*
935 * Note that there is absolutely no sense in writing out
936 * anonymous objects, so we track down the vnode object
937 * to write out.
938 * We invalidate (remove) all pages from the address space
939 * for semantic correctness.
940 *
941 * If the backing object is a device object with unmanaged pages, then any
942 * mappings to the specified range of pages must be removed before this
943 * function is called.
944 *
945 * Note: certain anonymous maps, such as MAP_NOSYNC maps,
946 * may start out with a NULL object.
947 */
948boolean_t
949vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size,
950 boolean_t syncio, boolean_t invalidate)
951{
952 vm_object_t backing_object;
953 struct vnode *vp;
954 struct mount *mp;
955 int error, flags, fsync_after;
956 boolean_t res;
957
958 if (object == NULL)
959 return (TRUE);
960 res = TRUE;
961 error = 0;
962 VM_OBJECT_LOCK(object);
963 while ((backing_object = object->backing_object) != NULL) {
964 VM_OBJECT_LOCK(backing_object);
965 offset += object->backing_object_offset;
966 VM_OBJECT_UNLOCK(object);
967 object = backing_object;
968 if (object->size < OFF_TO_IDX(offset + size))
969 size = IDX_TO_OFF(object->size) - offset;
970 }
971 /*
972 * Flush pages if writing is allowed, invalidate them
973 * if invalidation requested. Pages undergoing I/O
974 * will be ignored by vm_object_page_remove().
975 *
976 * We cannot lock the vnode and then wait for paging
977 * to complete without deadlocking against vm_fault.
978 * Instead we simply call vm_object_page_remove() and
979 * allow it to block internally on a page-by-page
980 * basis when it encounters pages undergoing async
981 * I/O.
982 */
983 if (object->type == OBJT_VNODE &&
984 (object->flags & OBJ_MIGHTBEDIRTY) != 0) {
985 vp = object->handle;
986 VM_OBJECT_UNLOCK(object);
987 (void) vn_start_write(vp, &mp, V_WAIT);
988 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
989 if (syncio && !invalidate && offset == 0 &&
990 OFF_TO_IDX(size) == object->size) {
991 /*
992 * If syncing the whole mapping of the file,
993 * it is faster to schedule all the writes in
994 * async mode, also allowing the clustering,
995 * and then wait for i/o to complete.
996 */
997 flags = 0;
998 fsync_after = TRUE;
999 } else {
1000 flags = (syncio || invalidate) ? OBJPC_SYNC : 0;
1001 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0;
1002 fsync_after = FALSE;
1003 }
1004 VM_OBJECT_LOCK(object);
1005 res = vm_object_page_clean(object, offset, offset + size,
1006 flags);
1007 VM_OBJECT_UNLOCK(object);
1008 if (fsync_after)
1009 error = VOP_FSYNC(vp, MNT_WAIT, curthread);
1010 VOP_UNLOCK(vp, 0);
1011 vn_finished_write(mp);
1012 if (error != 0)
1013 res = FALSE;
1014 VM_OBJECT_LOCK(object);
1015 }
1016 if ((object->type == OBJT_VNODE ||
1017 object->type == OBJT_DEVICE) && invalidate) {
1018 if (object->type == OBJT_DEVICE)
1019 /*
1020 * The option OBJPR_NOTMAPPED must be passed here
1021 * because vm_object_page_remove() cannot remove
1022 * unmanaged mappings.
1023 */
1024 flags = OBJPR_NOTMAPPED;
1025 else if (old_msync)
1026 flags = 0;
1027 else
1028 flags = OBJPR_CLEANONLY;
1029 vm_object_page_remove(object, OFF_TO_IDX(offset),
1030 OFF_TO_IDX(offset + size + PAGE_MASK), flags);
1031 }
1032 VM_OBJECT_UNLOCK(object);
1033 return (res);
1034}
1035
1036/*
1037 * vm_object_madvise:
1038 *
1039 * Implements the madvise function at the object/page level.
1040 *
1041 * MADV_WILLNEED (any object)
1042 *
1043 * Activate the specified pages if they are resident.
1044 *
1045 * MADV_DONTNEED (any object)
1046 *
1047 * Deactivate the specified pages if they are resident.
1048 *
1049 * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects,
1050 * OBJ_ONEMAPPING only)
1051 *
1052 * Deactivate and clean the specified pages if they are
1053 * resident. This permits the process to reuse the pages
1054 * without faulting or the kernel to reclaim the pages
1055 * without I/O.
1056 */
1057void
1058vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end,
1059 int advise)
1060{
1061 vm_pindex_t tpindex;
1062 vm_object_t backing_object, tobject;
1063 vm_page_t m;
1064
1065 if (object == NULL)
1066 return;
1067 VM_OBJECT_LOCK(object);
1068 /*
1069 * Locate and adjust resident pages
1070 */
1071 for (; pindex < end; pindex += 1) {
1072relookup:
1073 tobject = object;
1074 tpindex = pindex;
1075shadowlookup:
1076 /*
1077 * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages
1078 * and those pages must be OBJ_ONEMAPPING.
1079 */
1080 if (advise == MADV_FREE) {
1081 if ((tobject->type != OBJT_DEFAULT &&
1082 tobject->type != OBJT_SWAP) ||
1083 (tobject->flags & OBJ_ONEMAPPING) == 0) {
1084 goto unlock_tobject;
1085 }
1086 } else if ((tobject->flags & OBJ_UNMANAGED) != 0)
1087 goto unlock_tobject;
1088 m = vm_page_lookup(tobject, tpindex);
1089 if (m == NULL && advise == MADV_WILLNEED) {
1090 /*
1091 * If the page is cached, reactivate it.
1092 */
1093 m = vm_page_alloc(tobject, tpindex, VM_ALLOC_IFCACHED |
1094 VM_ALLOC_NOBUSY);
1095 }
1096 if (m == NULL) {
1097 /*
1098 * There may be swap even if there is no backing page
1099 */
1100 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1101 swap_pager_freespace(tobject, tpindex, 1);
1102 /*
1103 * next object
1104 */
1105 backing_object = tobject->backing_object;
1106 if (backing_object == NULL)
1107 goto unlock_tobject;
1108 VM_OBJECT_LOCK(backing_object);
1109 tpindex += OFF_TO_IDX(tobject->backing_object_offset);
1110 if (tobject != object)
1111 VM_OBJECT_UNLOCK(tobject);
1112 tobject = backing_object;
1113 goto shadowlookup;
1114 } else if (m->valid != VM_PAGE_BITS_ALL)
1115 goto unlock_tobject;
1116 /*
1117 * If the page is not in a normal state, skip it.
1118 */
1119 vm_page_lock(m);
1120 if (m->hold_count != 0 || m->wire_count != 0) {
1121 vm_page_unlock(m);
1122 goto unlock_tobject;
1123 }
1124 KASSERT((m->flags & PG_FICTITIOUS) == 0,
1125 ("vm_object_madvise: page %p is fictitious", m));
1126 KASSERT((m->oflags & VPO_UNMANAGED) == 0,
1127 ("vm_object_madvise: page %p is not managed", m));
1128 if ((m->oflags & VPO_BUSY) || m->busy) {
1129 if (advise == MADV_WILLNEED) {
1130 /*
1131 * Reference the page before unlocking and
1132 * sleeping so that the page daemon is less
1133 * likely to reclaim it.
1134 */
1135 vm_page_aflag_set(m, PGA_REFERENCED);
1136 }
1137 vm_page_unlock(m);
1138 if (object != tobject)
1139 VM_OBJECT_UNLOCK(object);
1140 m->oflags |= VPO_WANTED;
1141 VM_OBJECT_SLEEP(tobject, m, PDROP | PVM, "madvpo", 0);
1142 VM_OBJECT_LOCK(object);
1143 goto relookup;
1144 }
1145 if (advise == MADV_WILLNEED) {
1146 vm_page_activate(m);
1147 } else if (advise == MADV_DONTNEED) {
1148 vm_page_dontneed(m);
1149 } else if (advise == MADV_FREE) {
1150 /*
1151 * Mark the page clean. This will allow the page
1152 * to be freed up by the system. However, such pages
1153 * are often reused quickly by malloc()/free()
1154 * so we do not do anything that would cause
1155 * a page fault if we can help it.
1156 *
1157 * Specifically, we do not try to actually free
1158 * the page now nor do we try to put it in the
1159 * cache (which would cause a page fault on reuse).
1160 *
1161 * But we do make the page is freeable as we
1162 * can without actually taking the step of unmapping
1163 * it.
1164 */
1165 pmap_clear_modify(m);
1166 m->dirty = 0;
1167 m->act_count = 0;
1168 vm_page_dontneed(m);
1169 }
1170 vm_page_unlock(m);
1171 if (advise == MADV_FREE && tobject->type == OBJT_SWAP)
1172 swap_pager_freespace(tobject, tpindex, 1);
1173unlock_tobject:
1174 if (tobject != object)
1175 VM_OBJECT_UNLOCK(tobject);
1176 }
1177 VM_OBJECT_UNLOCK(object);
1178}
1179
1180/*
1181 * vm_object_shadow:
1182 *
1183 * Create a new object which is backed by the
1184 * specified existing object range. The source
1185 * object reference is deallocated.
1186 *
1187 * The new object and offset into that object
1188 * are returned in the source parameters.
1189 */
1190void
1191vm_object_shadow(
1192 vm_object_t *object, /* IN/OUT */
1193 vm_ooffset_t *offset, /* IN/OUT */
1194 vm_size_t length)
1195{
1196 vm_object_t source;
1197 vm_object_t result;
1198
1199 source = *object;
1200
1201 /*
1202 * Don't create the new object if the old object isn't shared.
1203 */
1204 if (source != NULL) {
1205 VM_OBJECT_LOCK(source);
1206 if (source->ref_count == 1 &&
1207 source->handle == NULL &&
1208 (source->type == OBJT_DEFAULT ||
1209 source->type == OBJT_SWAP)) {
1210 VM_OBJECT_UNLOCK(source);
1211 return;
1212 }
1213 VM_OBJECT_UNLOCK(source);
1214 }
1215
1216 /*
1217 * Allocate a new object with the given length.
1218 */
1219 result = vm_object_allocate(OBJT_DEFAULT, atop(length));
1220
1221 /*
1222 * The new object shadows the source object, adding a reference to it.
1223 * Our caller changes his reference to point to the new object,
1224 * removing a reference to the source object. Net result: no change
1225 * of reference count.
1226 *
1227 * Try to optimize the result object's page color when shadowing
1228 * in order to maintain page coloring consistency in the combined
1229 * shadowed object.
1230 */
1231 result->backing_object = source;
1232 /*
1233 * Store the offset into the source object, and fix up the offset into
1234 * the new object.
1235 */
1236 result->backing_object_offset = *offset;
1237 if (source != NULL) {
1238 VM_OBJECT_LOCK(source);
1239 LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list);
1240 source->shadow_count++;
1241#if VM_NRESERVLEVEL > 0
1242 result->flags |= source->flags & OBJ_COLORED;
1243 result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) &
1244 ((1 << (VM_NFREEORDER - 1)) - 1);
1245#endif
1246 VM_OBJECT_UNLOCK(source);
1247 }
1248
1249
1250 /*
1251 * Return the new things
1252 */
1253 *offset = 0;
1254 *object = result;
1255}
1256
1257/*
1258 * vm_object_split:
1259 *
1260 * Split the pages in a map entry into a new object. This affords
1261 * easier removal of unused pages, and keeps object inheritance from
1262 * being a negative impact on memory usage.
1263 */
1264void
1265vm_object_split(vm_map_entry_t entry)
1266{
1267 vm_page_t m, m_next;
1268 vm_object_t orig_object, new_object, source;
1269 vm_pindex_t idx, offidxstart;
1270 vm_size_t size;
1271
1272 orig_object = entry->object.vm_object;
1273 if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP)
1274 return;
1275 if (orig_object->ref_count <= 1)
1276 return;
1277 VM_OBJECT_UNLOCK(orig_object);
1278
1279 offidxstart = OFF_TO_IDX(entry->offset);
1280 size = atop(entry->end - entry->start);
1281
1282 /*
1283 * If swap_pager_copy() is later called, it will convert new_object
1284 * into a swap object.
1285 */
1286 new_object = vm_object_allocate(OBJT_DEFAULT, size);
1287
1288 /*
1289 * At this point, the new object is still private, so the order in
1290 * which the original and new objects are locked does not matter.
1291 */
1292 VM_OBJECT_LOCK(new_object);
1293 VM_OBJECT_LOCK(orig_object);
1294 source = orig_object->backing_object;
1295 if (source != NULL) {
1296 VM_OBJECT_LOCK(source);
1297 if ((source->flags & OBJ_DEAD) != 0) {
1298 VM_OBJECT_UNLOCK(source);
1299 VM_OBJECT_UNLOCK(orig_object);
1300 VM_OBJECT_UNLOCK(new_object);
1301 vm_object_deallocate(new_object);
1302 VM_OBJECT_LOCK(orig_object);
1303 return;
1304 }
1305 LIST_INSERT_HEAD(&source->shadow_head,
1306 new_object, shadow_list);
1307 source->shadow_count++;
1308 vm_object_reference_locked(source); /* for new_object */
1309 vm_object_clear_flag(source, OBJ_ONEMAPPING);
1310 VM_OBJECT_UNLOCK(source);
1311 new_object->backing_object_offset =
1312 orig_object->backing_object_offset + entry->offset;
1313 new_object->backing_object = source;
1314 }
1315 if (orig_object->cred != NULL) {
1316 new_object->cred = orig_object->cred;
1317 crhold(orig_object->cred);
1318 new_object->charge = ptoa(size);
1319 KASSERT(orig_object->charge >= ptoa(size),
1320 ("orig_object->charge < 0"));
1321 orig_object->charge -= ptoa(size);
1322 }
1323retry:
1324 m = vm_page_find_least(orig_object, offidxstart);
1325 for (; m != NULL && (idx = m->pindex - offidxstart) < size;
1326 m = m_next) {
1327 m_next = TAILQ_NEXT(m, listq);
1328
1329 /*
1330 * We must wait for pending I/O to complete before we can
1331 * rename the page.
1332 *
1333 * We do not have to VM_PROT_NONE the page as mappings should
1334 * not be changed by this operation.
1335 */
1336 if ((m->oflags & VPO_BUSY) || m->busy) {
1337 VM_OBJECT_UNLOCK(new_object);
1338 m->oflags |= VPO_WANTED;
1339 VM_OBJECT_SLEEP(orig_object, m, PVM, "spltwt", 0);
1340 VM_OBJECT_LOCK(new_object);
1341 goto retry;
1342 }
1343#if VM_NRESERVLEVEL > 0
1344 /*
1345 * If some of the reservation's allocated pages remain with
1346 * the original object, then transferring the reservation to
1347 * the new object is neither particularly beneficial nor
1348 * particularly harmful as compared to leaving the reservation
1349 * with the original object. If, however, all of the
1350 * reservation's allocated pages are transferred to the new
1351 * object, then transferring the reservation is typically
1352 * beneficial. Determining which of these two cases applies
1353 * would be more costly than unconditionally renaming the
1354 * reservation.
1355 */
1356 vm_reserv_rename(m, new_object, orig_object, offidxstart);
1357#endif
1358 vm_page_lock(m);
1359 vm_page_rename(m, new_object, idx);
1360 vm_page_unlock(m);
1361 /* page automatically made dirty by rename and cache handled */
1362 vm_page_busy(m);
1363 }
1364 if (orig_object->type == OBJT_SWAP) {
1365 /*
1366 * swap_pager_copy() can sleep, in which case the orig_object's
1367 * and new_object's locks are released and reacquired.
1368 */
1369 swap_pager_copy(orig_object, new_object, offidxstart, 0);
1370
1371 /*
1372 * Transfer any cached pages from orig_object to new_object.
1373 * If swap_pager_copy() found swapped out pages within the
1374 * specified range of orig_object, then it changed
1375 * new_object's type to OBJT_SWAP when it transferred those
1376 * pages to new_object. Otherwise, new_object's type
1377 * should still be OBJT_DEFAULT and orig_object should not
1378 * contain any cached pages within the specified range.
1379 */
1380 if (__predict_false(orig_object->cache != NULL))
1381 vm_page_cache_transfer(orig_object, offidxstart,
1382 new_object);
1383 }
1384 VM_OBJECT_UNLOCK(orig_object);
1385 TAILQ_FOREACH(m, &new_object->memq, listq)
1386 vm_page_wakeup(m);
1387 VM_OBJECT_UNLOCK(new_object);
1388 entry->object.vm_object = new_object;
1389 entry->offset = 0LL;
1390 vm_object_deallocate(orig_object);
1391 VM_OBJECT_LOCK(new_object);
1392}
1393
1394#define OBSC_TEST_ALL_SHADOWED 0x0001
1395#define OBSC_COLLAPSE_NOWAIT 0x0002
1396#define OBSC_COLLAPSE_WAIT 0x0004
1397
1398static int
1399vm_object_backing_scan(vm_object_t object, int op)
1400{
1401 int r = 1;
1402 vm_page_t p;
1403 vm_object_t backing_object;
1404 vm_pindex_t backing_offset_index;
1405
1406 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1407 VM_OBJECT_LOCK_ASSERT(object->backing_object, MA_OWNED);
1408
1409 backing_object = object->backing_object;
1410 backing_offset_index = OFF_TO_IDX(object->backing_object_offset);
1411
1412 /*
1413 * Initial conditions
1414 */
1415 if (op & OBSC_TEST_ALL_SHADOWED) {
1416 /*
1417 * We do not want to have to test for the existence of cache
1418 * or swap pages in the backing object. XXX but with the
1419 * new swapper this would be pretty easy to do.
1420 *
1421 * XXX what about anonymous MAP_SHARED memory that hasn't
1422 * been ZFOD faulted yet? If we do not test for this, the
1423 * shadow test may succeed! XXX
1424 */
1425 if (backing_object->type != OBJT_DEFAULT) {
1426 return (0);
1427 }
1428 }
1429 if (op & OBSC_COLLAPSE_WAIT) {
1430 vm_object_set_flag(backing_object, OBJ_DEAD);
1431 }
1432
1433 /*
1434 * Our scan
1435 */
1436 p = TAILQ_FIRST(&backing_object->memq);
1437 while (p) {
1438 vm_page_t next = TAILQ_NEXT(p, listq);
1439 vm_pindex_t new_pindex = p->pindex - backing_offset_index;
1440
1441 if (op & OBSC_TEST_ALL_SHADOWED) {
1442 vm_page_t pp;
1443
1444 /*
1445 * Ignore pages outside the parent object's range
1446 * and outside the parent object's mapping of the
1447 * backing object.
1448 *
1449 * note that we do not busy the backing object's
1450 * page.
1451 */
1452 if (
1453 p->pindex < backing_offset_index ||
1454 new_pindex >= object->size
1455 ) {
1456 p = next;
1457 continue;
1458 }
1459
1460 /*
1461 * See if the parent has the page or if the parent's
1462 * object pager has the page. If the parent has the
1463 * page but the page is not valid, the parent's
1464 * object pager must have the page.
1465 *
1466 * If this fails, the parent does not completely shadow
1467 * the object and we might as well give up now.
1468 */
1469
1470 pp = vm_page_lookup(object, new_pindex);
1471 if (
1472 (pp == NULL || pp->valid == 0) &&
1473 !vm_pager_has_page(object, new_pindex, NULL, NULL)
1474 ) {
1475 r = 0;
1476 break;
1477 }
1478 }
1479
1480 /*
1481 * Check for busy page
1482 */
1483 if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) {
1484 vm_page_t pp;
1485
1486 if (op & OBSC_COLLAPSE_NOWAIT) {
1487 if ((p->oflags & VPO_BUSY) ||
1488 !p->valid ||
1489 p->busy) {
1490 p = next;
1491 continue;
1492 }
1493 } else if (op & OBSC_COLLAPSE_WAIT) {
1494 if ((p->oflags & VPO_BUSY) || p->busy) {
1495 VM_OBJECT_UNLOCK(object);
1496 p->oflags |= VPO_WANTED;
1497 VM_OBJECT_SLEEP(backing_object, p,
1498 PDROP | PVM, "vmocol", 0);
1499 VM_OBJECT_LOCK(object);
1500 VM_OBJECT_LOCK(backing_object);
1501 /*
1502 * If we slept, anything could have
1503 * happened. Since the object is
1504 * marked dead, the backing offset
1505 * should not have changed so we
1506 * just restart our scan.
1507 */
1508 p = TAILQ_FIRST(&backing_object->memq);
1509 continue;
1510 }
1511 }
1512
1513 KASSERT(
1514 p->object == backing_object,
1515 ("vm_object_backing_scan: object mismatch")
1516 );
1517
1518 /*
1519 * Destroy any associated swap
1520 */
1521 if (backing_object->type == OBJT_SWAP) {
1522 swap_pager_freespace(
1523 backing_object,
1524 p->pindex,
1525 1
1526 );
1527 }
1528
1529 if (
1530 p->pindex < backing_offset_index ||
1531 new_pindex >= object->size
1532 ) {
1533 /*
1534 * Page is out of the parent object's range, we
1535 * can simply destroy it.
1536 */
1537 vm_page_lock(p);
1538 KASSERT(!pmap_page_is_mapped(p),
1539 ("freeing mapped page %p", p));
1540 if (p->wire_count == 0)
1541 vm_page_free(p);
1542 else
1543 vm_page_remove(p);
1544 vm_page_unlock(p);
1545 p = next;
1546 continue;
1547 }
1548
1549 pp = vm_page_lookup(object, new_pindex);
1550 if (
1551 (op & OBSC_COLLAPSE_NOWAIT) != 0 &&
1552 (pp != NULL && pp->valid == 0)
1553 ) {
1554 /*
1555 * The page in the parent is not (yet) valid.
1556 * We don't know anything about the state of
1557 * the original page. It might be mapped,
1558 * so we must avoid the next if here.
1559 *
1560 * This is due to a race in vm_fault() where
1561 * we must unbusy the original (backing_obj)
1562 * page before we can (re)lock the parent.
1563 * Hence we can get here.
1564 */
1565 p = next;
1566 continue;
1567 }
1568 if (
1569 pp != NULL ||
1570 vm_pager_has_page(object, new_pindex, NULL, NULL)
1571 ) {
1572 /*
1573 * page already exists in parent OR swap exists
1574 * for this location in the parent. Destroy
1575 * the original page from the backing object.
1576 *
1577 * Leave the parent's page alone
1578 */
1579 vm_page_lock(p);
1580 KASSERT(!pmap_page_is_mapped(p),
1581 ("freeing mapped page %p", p));
1582 if (p->wire_count == 0)
1583 vm_page_free(p);
1584 else
1585 vm_page_remove(p);
1586 vm_page_unlock(p);
1587 p = next;
1588 continue;
1589 }
1590
1591#if VM_NRESERVLEVEL > 0
1592 /*
1593 * Rename the reservation.
1594 */
1595 vm_reserv_rename(p, object, backing_object,
1596 backing_offset_index);
1597#endif
1598
1599 /*
1600 * Page does not exist in parent, rename the
1601 * page from the backing object to the main object.
1602 *
1603 * If the page was mapped to a process, it can remain
1604 * mapped through the rename.
1605 */
1606 vm_page_lock(p);
1607 vm_page_rename(p, object, new_pindex);
1608 vm_page_unlock(p);
1609 /* page automatically made dirty by rename */
1610 }
1611 p = next;
1612 }
1613 return (r);
1614}
1615
1616
1617/*
1618 * this version of collapse allows the operation to occur earlier and
1619 * when paging_in_progress is true for an object... This is not a complete
1620 * operation, but should plug 99.9% of the rest of the leaks.
1621 */
1622static void
1623vm_object_qcollapse(vm_object_t object)
1624{
1625 vm_object_t backing_object = object->backing_object;
1626
1627 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1628 VM_OBJECT_LOCK_ASSERT(backing_object, MA_OWNED);
1629
1630 if (backing_object->ref_count != 1)
1631 return;
1632
1633 vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT);
1634}
1635
1636/*
1637 * vm_object_collapse:
1638 *
1639 * Collapse an object with the object backing it.
1640 * Pages in the backing object are moved into the
1641 * parent, and the backing object is deallocated.
1642 */
1643void
1644vm_object_collapse(vm_object_t object)
1645{
1646 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1647
1648 while (TRUE) {
1649 vm_object_t backing_object;
1650
1651 /*
1652 * Verify that the conditions are right for collapse:
1653 *
1654 * The object exists and the backing object exists.
1655 */
1656 if ((backing_object = object->backing_object) == NULL)
1657 break;
1658
1659 /*
1660 * we check the backing object first, because it is most likely
1661 * not collapsable.
1662 */
1663 VM_OBJECT_LOCK(backing_object);
1664 if (backing_object->handle != NULL ||
1665 (backing_object->type != OBJT_DEFAULT &&
1666 backing_object->type != OBJT_SWAP) ||
1667 (backing_object->flags & OBJ_DEAD) ||
1668 object->handle != NULL ||
1669 (object->type != OBJT_DEFAULT &&
1670 object->type != OBJT_SWAP) ||
1671 (object->flags & OBJ_DEAD)) {
1672 VM_OBJECT_UNLOCK(backing_object);
1673 break;
1674 }
1675
1676 if (
1677 object->paging_in_progress != 0 ||
1678 backing_object->paging_in_progress != 0
1679 ) {
1680 vm_object_qcollapse(object);
1681 VM_OBJECT_UNLOCK(backing_object);
1682 break;
1683 }
1684 /*
1685 * We know that we can either collapse the backing object (if
1686 * the parent is the only reference to it) or (perhaps) have
1687 * the parent bypass the object if the parent happens to shadow
1688 * all the resident pages in the entire backing object.
1689 *
1690 * This is ignoring pager-backed pages such as swap pages.
1691 * vm_object_backing_scan fails the shadowing test in this
1692 * case.
1693 */
1694 if (backing_object->ref_count == 1) {
1695 /*
1696 * If there is exactly one reference to the backing
1697 * object, we can collapse it into the parent.
1698 */
1699 vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT);
1700
1701#if VM_NRESERVLEVEL > 0
1702 /*
1703 * Break any reservations from backing_object.
1704 */
1705 if (__predict_false(!LIST_EMPTY(&backing_object->rvq)))
1706 vm_reserv_break_all(backing_object);
1707#endif
1708
1709 /*
1710 * Move the pager from backing_object to object.
1711 */
1712 if (backing_object->type == OBJT_SWAP) {
1713 /*
1714 * swap_pager_copy() can sleep, in which case
1715 * the backing_object's and object's locks are
1716 * released and reacquired.
1717 * Since swap_pager_copy() is being asked to
1718 * destroy the source, it will change the
1719 * backing_object's type to OBJT_DEFAULT.
1720 */
1721 swap_pager_copy(
1722 backing_object,
1723 object,
1724 OFF_TO_IDX(object->backing_object_offset), TRUE);
1725
1726 /*
1727 * Free any cached pages from backing_object.
1728 */
1729 if (__predict_false(backing_object->cache != NULL))
1730 vm_page_cache_free(backing_object, 0, 0);
1731 }
1732 /*
1733 * Object now shadows whatever backing_object did.
1734 * Note that the reference to
1735 * backing_object->backing_object moves from within
1736 * backing_object to within object.
1737 */
1738 LIST_REMOVE(object, shadow_list);
1739 backing_object->shadow_count--;
1740 if (backing_object->backing_object) {
1741 VM_OBJECT_LOCK(backing_object->backing_object);
1742 LIST_REMOVE(backing_object, shadow_list);
1743 LIST_INSERT_HEAD(
1744 &backing_object->backing_object->shadow_head,
1745 object, shadow_list);
1746 /*
1747 * The shadow_count has not changed.
1748 */
1749 VM_OBJECT_UNLOCK(backing_object->backing_object);
1750 }
1751 object->backing_object = backing_object->backing_object;
1752 object->backing_object_offset +=
1753 backing_object->backing_object_offset;
1754
1755 /*
1756 * Discard backing_object.
1757 *
1758 * Since the backing object has no pages, no pager left,
1759 * and no object references within it, all that is
1760 * necessary is to dispose of it.
1761 */
1762 KASSERT(backing_object->ref_count == 1, (
1763"backing_object %p was somehow re-referenced during collapse!",
1764 backing_object));
1765 VM_OBJECT_UNLOCK(backing_object);
1766 vm_object_destroy(backing_object);
1767
1768 object_collapses++;
1769 } else {
1770 vm_object_t new_backing_object;
1771
1772 /*
1773 * If we do not entirely shadow the backing object,
1774 * there is nothing we can do so we give up.
1775 */
1776 if (object->resident_page_count != object->size &&
1777 vm_object_backing_scan(object,
1778 OBSC_TEST_ALL_SHADOWED) == 0) {
1779 VM_OBJECT_UNLOCK(backing_object);
1780 break;
1781 }
1782
1783 /*
1784 * Make the parent shadow the next object in the
1785 * chain. Deallocating backing_object will not remove
1786 * it, since its reference count is at least 2.
1787 */
1788 LIST_REMOVE(object, shadow_list);
1789 backing_object->shadow_count--;
1790
1791 new_backing_object = backing_object->backing_object;
1792 if ((object->backing_object = new_backing_object) != NULL) {
1793 VM_OBJECT_LOCK(new_backing_object);
1794 LIST_INSERT_HEAD(
1795 &new_backing_object->shadow_head,
1796 object,
1797 shadow_list
1798 );
1799 new_backing_object->shadow_count++;
1800 vm_object_reference_locked(new_backing_object);
1801 VM_OBJECT_UNLOCK(new_backing_object);
1802 object->backing_object_offset +=
1803 backing_object->backing_object_offset;
1804 }
1805
1806 /*
1807 * Drop the reference count on backing_object. Since
1808 * its ref_count was at least 2, it will not vanish.
1809 */
1810 backing_object->ref_count--;
1811 VM_OBJECT_UNLOCK(backing_object);
1812 object_bypasses++;
1813 }
1814
1815 /*
1816 * Try again with this object's new backing object.
1817 */
1818 }
1819}
1820
1821/*
1822 * vm_object_page_remove:
1823 *
1824 * For the given object, either frees or invalidates each of the
1825 * specified pages. In general, a page is freed. However, if a page is
1826 * wired for any reason other than the existence of a managed, wired
1827 * mapping, then it may be invalidated but not removed from the object.
1828 * Pages are specified by the given range ["start", "end") and the option
1829 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range
1830 * extends from "start" to the end of the object. If the option
1831 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the
1832 * specified range are affected. If the option OBJPR_NOTMAPPED is
1833 * specified, then the pages within the specified range must have no
1834 * mappings. Otherwise, if this option is not specified, any mappings to
1835 * the specified pages are removed before the pages are freed or
1836 * invalidated.
1837 *
1838 * In general, this operation should only be performed on objects that
1839 * contain managed pages. There are, however, two exceptions. First, it
1840 * is performed on the kernel and kmem objects by vm_map_entry_delete().
1841 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device-
1842 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must
1843 * not be specified and the option OBJPR_NOTMAPPED must be specified.
1844 *
1845 * The object must be locked.
1846 */
1847void
1848vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end,
1849 int options)
1850{
1851 vm_page_t p, next;
1852 int wirings;
1853
1854 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1855 KASSERT((object->flags & OBJ_UNMANAGED) == 0 ||
1856 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED,
1857 ("vm_object_page_remove: illegal options for object %p", object));
1858 if (object->resident_page_count == 0)
1859 goto skipmemq;
1860 vm_object_pip_add(object, 1);
1861again:
1862 p = vm_page_find_least(object, start);
1863
1864 /*
1865 * Here, the variable "p" is either (1) the page with the least pindex
1866 * greater than or equal to the parameter "start" or (2) NULL.
1867 */
1868 for (; p != NULL && (p->pindex < end || end == 0); p = next) {
1869 next = TAILQ_NEXT(p, listq);
1870
1871 /*
1872 * If the page is wired for any reason besides the existence
1873 * of managed, wired mappings, then it cannot be freed. For
1874 * example, fictitious pages, which represent device memory,
1875 * are inherently wired and cannot be freed. They can,
1876 * however, be invalidated if the option OBJPR_CLEANONLY is
1877 * not specified.
1878 */
1879 vm_page_lock(p);
1880 if ((wirings = p->wire_count) != 0 &&
1881 (wirings = pmap_page_wired_mappings(p)) != p->wire_count) {
1882 if ((options & OBJPR_NOTMAPPED) == 0) {
1883 pmap_remove_all(p);
1884 /* Account for removal of wired mappings. */
1885 if (wirings != 0)
1886 p->wire_count -= wirings;
1887 }
1888 if ((options & OBJPR_CLEANONLY) == 0) {
1889 p->valid = 0;
1890 vm_page_undirty(p);
1891 }
1892 vm_page_unlock(p);
1893 continue;
1894 }
1895 if (vm_page_sleep_if_busy(p, TRUE, "vmopar"))
1896 goto again;
1897 KASSERT((p->flags & PG_FICTITIOUS) == 0,
1898 ("vm_object_page_remove: page %p is fictitious", p));
1899 if ((options & OBJPR_CLEANONLY) != 0 && p->valid != 0) {
1900 if ((options & OBJPR_NOTMAPPED) == 0)
1901 pmap_remove_write(p);
1902 if (p->dirty) {
1903 vm_page_unlock(p);
1904 continue;
1905 }
1906 }
1907 if ((options & OBJPR_NOTMAPPED) == 0) {
1908 pmap_remove_all(p);
1909 /* Account for removal of wired mappings. */
1910 if (wirings != 0) {
1911 KASSERT(p->wire_count == wirings,
1912 ("inconsistent wire count %d %d %p",
1913 p->wire_count, wirings, p));
1914 p->wire_count = 0;
1915 atomic_subtract_int(&cnt.v_wire_count, 1);
1916 }
1917 }
1918 vm_page_free(p);
1919 vm_page_unlock(p);
1920 }
1921 vm_object_pip_wakeup(object);
1922skipmemq:
1923 if (__predict_false(object->cache != NULL))
1924 vm_page_cache_free(object, start, end);
1925}
1926
1927/*
1928 * vm_object_page_cache:
1929 *
1930 * For the given object, attempt to move the specified clean
1931 * pages to the cache queue. If a page is wired for any reason,
1932 * then it will not be changed. Pages are specified by the given
1933 * range ["start", "end"). As a special case, if "end" is zero,
1934 * then the range extends from "start" to the end of the object.
1935 * Any mappings to the specified pages are removed before the
1936 * pages are moved to the cache queue.
1937 *
1938 * This operation should only be performed on objects that
1939 * contain non-fictitious, managed pages.
1940 *
1941 * The object must be locked.
1942 */
1943void
1944vm_object_page_cache(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
1945{
1946 struct mtx *mtx, *new_mtx;
1947 vm_page_t p, next;
1948
1949 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1950 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0,
1951 ("vm_object_page_cache: illegal object %p", object));
1952 if (object->resident_page_count == 0)
1953 return;
1954 p = vm_page_find_least(object, start);
1955
1956 /*
1957 * Here, the variable "p" is either (1) the page with the least pindex
1958 * greater than or equal to the parameter "start" or (2) NULL.
1959 */
1960 mtx = NULL;
1961 for (; p != NULL && (p->pindex < end || end == 0); p = next) {
1962 next = TAILQ_NEXT(p, listq);
1963
1964 /*
1965 * Avoid releasing and reacquiring the same page lock.
1966 */
1967 new_mtx = vm_page_lockptr(p);
1968 if (mtx != new_mtx) {
1969 if (mtx != NULL)
1970 mtx_unlock(mtx);
1971 mtx = new_mtx;
1972 mtx_lock(mtx);
1973 }
1974 vm_page_try_to_cache(p);
1975 }
1976 if (mtx != NULL)
1977 mtx_unlock(mtx);
1978}
1979
1980/*
1981 * Populate the specified range of the object with valid pages. Returns
1982 * TRUE if the range is successfully populated and FALSE otherwise.
1983 *
1984 * Note: This function should be optimized to pass a larger array of
1985 * pages to vm_pager_get_pages() before it is applied to a non-
1986 * OBJT_DEVICE object.
1987 *
1988 * The object must be locked.
1989 */
1990boolean_t
1991vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
1992{
1993 vm_page_t m, ma[1];
1994 vm_pindex_t pindex;
1995 int rv;
1996
1997 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
1998 for (pindex = start; pindex < end; pindex++) {
1999 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL |
2000 VM_ALLOC_RETRY);
2001 if (m->valid != VM_PAGE_BITS_ALL) {
2002 ma[0] = m;
2003 rv = vm_pager_get_pages(object, ma, 1, 0);
2004 m = vm_page_lookup(object, pindex);
2005 if (m == NULL)
2006 break;
2007 if (rv != VM_PAGER_OK) {
2008 vm_page_lock(m);
2009 vm_page_free(m);
2010 vm_page_unlock(m);
2011 break;
2012 }
2013 }
2014 /*
2015 * Keep "m" busy because a subsequent iteration may unlock
2016 * the object.
2017 */
2018 }
2019 if (pindex > start) {
2020 m = vm_page_lookup(object, start);
2021 while (m != NULL && m->pindex < pindex) {
2022 vm_page_wakeup(m);
2023 m = TAILQ_NEXT(m, listq);
2024 }
2025 }
2026 return (pindex == end);
2027}
2028
2029/*
2030 * Routine: vm_object_coalesce
2031 * Function: Coalesces two objects backing up adjoining
2032 * regions of memory into a single object.
2033 *
2034 * returns TRUE if objects were combined.
2035 *
2036 * NOTE: Only works at the moment if the second object is NULL -
2037 * if it's not, which object do we lock first?
2038 *
2039 * Parameters:
2040 * prev_object First object to coalesce
2041 * prev_offset Offset into prev_object
2042 * prev_size Size of reference to prev_object
2043 * next_size Size of reference to the second object
2044 * reserved Indicator that extension region has
2045 * swap accounted for
2046 *
2047 * Conditions:
2048 * The object must *not* be locked.
2049 */
2050boolean_t
2051vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset,
2052 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved)
2053{
2054 vm_pindex_t next_pindex;
2055
2056 if (prev_object == NULL)
2057 return (TRUE);
2058 VM_OBJECT_LOCK(prev_object);
2059 if (prev_object->type != OBJT_DEFAULT &&
2060 prev_object->type != OBJT_SWAP) {
2061 VM_OBJECT_UNLOCK(prev_object);
2062 return (FALSE);
2063 }
2064
2065 /*
2066 * Try to collapse the object first
2067 */
2068 vm_object_collapse(prev_object);
2069
2070 /*
2071 * Can't coalesce if: . more than one reference . paged out . shadows
2072 * another object . has a copy elsewhere (any of which mean that the
2073 * pages not mapped to prev_entry may be in use anyway)
2074 */
2075 if (prev_object->backing_object != NULL) {
2076 VM_OBJECT_UNLOCK(prev_object);
2077 return (FALSE);
2078 }
2079
2080 prev_size >>= PAGE_SHIFT;
2081 next_size >>= PAGE_SHIFT;
2082 next_pindex = OFF_TO_IDX(prev_offset) + prev_size;
2083
2084 if ((prev_object->ref_count > 1) &&
2085 (prev_object->size != next_pindex)) {
2086 VM_OBJECT_UNLOCK(prev_object);
2087 return (FALSE);
2088 }
2089
2090 /*
2091 * Account for the charge.
2092 */
2093 if (prev_object->cred != NULL) {
2094
2095 /*
2096 * If prev_object was charged, then this mapping,
2097 * althought not charged now, may become writable
2098 * later. Non-NULL cred in the object would prevent
2099 * swap reservation during enabling of the write
2100 * access, so reserve swap now. Failed reservation
2101 * cause allocation of the separate object for the map
2102 * entry, and swap reservation for this entry is
2103 * managed in appropriate time.
2104 */
2105 if (!reserved && !swap_reserve_by_cred(ptoa(next_size),
2106 prev_object->cred)) {
2107 return (FALSE);
2108 }
2109 prev_object->charge += ptoa(next_size);
2110 }
2111
2112 /*
2113 * Remove any pages that may still be in the object from a previous
2114 * deallocation.
2115 */
2116 if (next_pindex < prev_object->size) {
2117 vm_object_page_remove(prev_object, next_pindex, next_pindex +
2118 next_size, 0);
2119 if (prev_object->type == OBJT_SWAP)
2120 swap_pager_freespace(prev_object,
2121 next_pindex, next_size);
2122#if 0
2123 if (prev_object->cred != NULL) {
2124 KASSERT(prev_object->charge >=
2125 ptoa(prev_object->size - next_pindex),
2126 ("object %p overcharged 1 %jx %jx", prev_object,
2127 (uintmax_t)next_pindex, (uintmax_t)next_size));
2128 prev_object->charge -= ptoa(prev_object->size -
2129 next_pindex);
2130 }
2131#endif
2132 }
2133
2134 /*
2135 * Extend the object if necessary.
2136 */
2137 if (next_pindex + next_size > prev_object->size)
2138 prev_object->size = next_pindex + next_size;
2139
2140 VM_OBJECT_UNLOCK(prev_object);
2141 return (TRUE);
2142}
2143
2144void
2145vm_object_set_writeable_dirty(vm_object_t object)
2146{
2147
2148 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
2149 if (object->type != OBJT_VNODE)
2150 return;
2151 object->generation++;
2152 if ((object->flags & OBJ_MIGHTBEDIRTY) != 0)
2153 return;
2154 vm_object_set_flag(object, OBJ_MIGHTBEDIRTY);
2155}
2156
2157#include "opt_ddb.h"
2158#ifdef DDB
2159#include <sys/kernel.h>
2160
2161#include <sys/cons.h>
2162
2163#include <ddb/ddb.h>
2164
2165static int
2166_vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry)
2167{
2168 vm_map_t tmpm;
2169 vm_map_entry_t tmpe;
2170 vm_object_t obj;
2171 int entcount;
2172
2173 if (map == 0)
2174 return 0;
2175
2176 if (entry == 0) {
2177 tmpe = map->header.next;
2178 entcount = map->nentries;
2179 while (entcount-- && (tmpe != &map->header)) {
2180 if (_vm_object_in_map(map, object, tmpe)) {
2181 return 1;
2182 }
2183 tmpe = tmpe->next;
2184 }
2185 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) {
2186 tmpm = entry->object.sub_map;
2187 tmpe = tmpm->header.next;
2188 entcount = tmpm->nentries;
2189 while (entcount-- && tmpe != &tmpm->header) {
2190 if (_vm_object_in_map(tmpm, object, tmpe)) {
2191 return 1;
2192 }
2193 tmpe = tmpe->next;
2194 }
2195 } else if ((obj = entry->object.vm_object) != NULL) {
2196 for (; obj; obj = obj->backing_object)
2197 if (obj == object) {
2198 return 1;
2199 }
2200 }
2201 return 0;
2202}
2203
2204static int
2205vm_object_in_map(vm_object_t object)
2206{
2207 struct proc *p;
2208
2209 /* sx_slock(&allproc_lock); */
2210 FOREACH_PROC_IN_SYSTEM(p) {
2211 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */)
2212 continue;
2213 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) {
2214 /* sx_sunlock(&allproc_lock); */
2215 return 1;
2216 }
2217 }
2218 /* sx_sunlock(&allproc_lock); */
2219 if (_vm_object_in_map(kernel_map, object, 0))
2220 return 1;
2221 if (_vm_object_in_map(kmem_map, object, 0))
2222 return 1;
2223 if (_vm_object_in_map(pager_map, object, 0))
2224 return 1;
2225 if (_vm_object_in_map(buffer_map, object, 0))
2226 return 1;
2227 return 0;
2228}
2229
2230DB_SHOW_COMMAND(vmochk, vm_object_check)
2231{
2232 vm_object_t object;
2233
2234 /*
2235 * make sure that internal objs are in a map somewhere
2236 * and none have zero ref counts.
2237 */
2238 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2239 if (object->handle == NULL &&
2240 (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) {
2241 if (object->ref_count == 0) {
2242 db_printf("vmochk: internal obj has zero ref count: %ld\n",
2243 (long)object->size);
2244 }
2245 if (!vm_object_in_map(object)) {
2246 db_printf(
2247 "vmochk: internal obj is not in a map: "
2248 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n",
2249 object->ref_count, (u_long)object->size,
2250 (u_long)object->size,
2251 (void *)object->backing_object);
2252 }
2253 }
2254 }
2255}
2256
2257/*
2258 * vm_object_print: [ debug ]
2259 */
2260DB_SHOW_COMMAND(object, vm_object_print_static)
2261{
2262 /* XXX convert args. */
2263 vm_object_t object = (vm_object_t)addr;
2264 boolean_t full = have_addr;
2265
2266 vm_page_t p;
2267
2268 /* XXX count is an (unused) arg. Avoid shadowing it. */
2269#define count was_count
2270
2271 int count;
2272
2273 if (object == NULL)
2274 return;
2275
2276 db_iprintf(
2277 "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x ruid %d charge %jx\n",
2278 object, (int)object->type, (uintmax_t)object->size,
2279 object->resident_page_count, object->ref_count, object->flags,
2280 object->cred ? object->cred->cr_ruid : -1, (uintmax_t)object->charge);
2281 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n",
2282 object->shadow_count,
2283 object->backing_object ? object->backing_object->ref_count : 0,
2284 object->backing_object, (uintmax_t)object->backing_object_offset);
2285
2286 if (!full)
2287 return;
2288
2289 db_indent += 2;
2290 count = 0;
2291 TAILQ_FOREACH(p, &object->memq, listq) {
2292 if (count == 0)
2293 db_iprintf("memory:=");
2294 else if (count == 6) {
2295 db_printf("\n");
2296 db_iprintf(" ...");
2297 count = 0;
2298 } else
2299 db_printf(",");
2300 count++;
2301
2302 db_printf("(off=0x%jx,page=0x%jx)",
2303 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p));
2304 }
2305 if (count != 0)
2306 db_printf("\n");
2307 db_indent -= 2;
2308}
2309
2310/* XXX. */
2311#undef count
2312
2313/* XXX need this non-static entry for calling from vm_map_print. */
2314void
2315vm_object_print(
2316 /* db_expr_t */ long addr,
2317 boolean_t have_addr,
2318 /* db_expr_t */ long count,
2319 char *modif)
2320{
2321 vm_object_print_static(addr, have_addr, count, modif);
2322}
2323
2324DB_SHOW_COMMAND(vmopag, vm_object_print_pages)
2325{
2326 vm_object_t object;
2327 vm_pindex_t fidx;
2328 vm_paddr_t pa;
2329 vm_page_t m, prev_m;
2330 int rcount, nl, c;
2331
2332 nl = 0;
2333 TAILQ_FOREACH(object, &vm_object_list, object_list) {
2334 db_printf("new object: %p\n", (void *)object);
2335 if (nl > 18) {
2336 c = cngetc();
2337 if (c != ' ')
2338 return;
2339 nl = 0;
2340 }
2341 nl++;
2342 rcount = 0;
2343 fidx = 0;
2344 pa = -1;
2345 TAILQ_FOREACH(m, &object->memq, listq) {
2346 if (m->pindex > 128)
2347 break;
2348 if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL &&
2349 prev_m->pindex + 1 != m->pindex) {
2350 if (rcount) {
2351 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2352 (long)fidx, rcount, (long)pa);
2353 if (nl > 18) {
2354 c = cngetc();
2355 if (c != ' ')
2356 return;
2357 nl = 0;
2358 }
2359 nl++;
2360 rcount = 0;
2361 }
2362 }
2363 if (rcount &&
2364 (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) {
2365 ++rcount;
2366 continue;
2367 }
2368 if (rcount) {
2369 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2370 (long)fidx, rcount, (long)pa);
2371 if (nl > 18) {
2372 c = cngetc();
2373 if (c != ' ')
2374 return;
2375 nl = 0;
2376 }
2377 nl++;
2378 }
2379 fidx = m->pindex;
2380 pa = VM_PAGE_TO_PHYS(m);
2381 rcount = 1;
2382 }
2383 if (rcount) {
2384 db_printf(" index(%ld)run(%d)pa(0x%lx)\n",
2385 (long)fidx, rcount, (long)pa);
2386 if (nl > 18) {
2387 c = cngetc();
2388 if (c != ' ')
2389 return;
2390 nl = 0;
2391 }
2392 nl++;
2393 }
2394 }
2395}
2396#endif /* DDB */
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