FreeBSD/Linux Kernel Cross Reference
sys/uvm/uvm_aobj.c
1 /* $NetBSD: uvm_aobj.c,v 1.82.2.1 2007/08/24 16:52:25 liamjfoy Exp $ */
2
3 /*
4 * Copyright (c) 1998 Chuck Silvers, Charles D. Cranor and
5 * Washington University.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by Charles D. Cranor and
19 * Washington University.
20 * 4. The name of the author may not be used to endorse or promote products
21 * derived from this software without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 *
34 * from: Id: uvm_aobj.c,v 1.1.2.5 1998/02/06 05:14:38 chs Exp
35 */
36 /*
37 * uvm_aobj.c: anonymous memory uvm_object pager
38 *
39 * author: Chuck Silvers <chuq@chuq.com>
40 * started: Jan-1998
41 *
42 * - design mostly from Chuck Cranor
43 */
44
45 #include <sys/cdefs.h>
46 __KERNEL_RCSID(0, "$NetBSD: uvm_aobj.c,v 1.82.2.1 2007/08/24 16:52:25 liamjfoy Exp $");
47
48 #include "opt_uvmhist.h"
49
50 #include <sys/param.h>
51 #include <sys/systm.h>
52 #include <sys/proc.h>
53 #include <sys/malloc.h>
54 #include <sys/kernel.h>
55 #include <sys/pool.h>
56 #include <sys/kernel.h>
57
58 #include <uvm/uvm.h>
59
60 /*
61 * an aobj manages anonymous-memory backed uvm_objects. in addition
62 * to keeping the list of resident pages, it also keeps a list of
63 * allocated swap blocks. depending on the size of the aobj this list
64 * of allocated swap blocks is either stored in an array (small objects)
65 * or in a hash table (large objects).
66 */
67
68 /*
69 * local structures
70 */
71
72 /*
73 * for hash tables, we break the address space of the aobj into blocks
74 * of UAO_SWHASH_CLUSTER_SIZE pages. we require the cluster size to
75 * be a power of two.
76 */
77
78 #define UAO_SWHASH_CLUSTER_SHIFT 4
79 #define UAO_SWHASH_CLUSTER_SIZE (1 << UAO_SWHASH_CLUSTER_SHIFT)
80
81 /* get the "tag" for this page index */
82 #define UAO_SWHASH_ELT_TAG(PAGEIDX) \
83 ((PAGEIDX) >> UAO_SWHASH_CLUSTER_SHIFT)
84
85 #define UAO_SWHASH_ELT_PAGESLOT_IDX(PAGEIDX) \
86 ((PAGEIDX) & (UAO_SWHASH_CLUSTER_SIZE - 1))
87
88 /* given an ELT and a page index, find the swap slot */
89 #define UAO_SWHASH_ELT_PAGESLOT(ELT, PAGEIDX) \
90 ((ELT)->slots[UAO_SWHASH_ELT_PAGESLOT_IDX(PAGEIDX)])
91
92 /* given an ELT, return its pageidx base */
93 #define UAO_SWHASH_ELT_PAGEIDX_BASE(ELT) \
94 ((ELT)->tag << UAO_SWHASH_CLUSTER_SHIFT)
95
96 /*
97 * the swhash hash function
98 */
99
100 #define UAO_SWHASH_HASH(AOBJ, PAGEIDX) \
101 (&(AOBJ)->u_swhash[(((PAGEIDX) >> UAO_SWHASH_CLUSTER_SHIFT) \
102 & (AOBJ)->u_swhashmask)])
103
104 /*
105 * the swhash threshhold determines if we will use an array or a
106 * hash table to store the list of allocated swap blocks.
107 */
108
109 #define UAO_SWHASH_THRESHOLD (UAO_SWHASH_CLUSTER_SIZE * 4)
110 #define UAO_USES_SWHASH(AOBJ) \
111 ((AOBJ)->u_pages > UAO_SWHASH_THRESHOLD) /* use hash? */
112
113 /*
114 * the number of buckets in a swhash, with an upper bound
115 */
116
117 #define UAO_SWHASH_MAXBUCKETS 256
118 #define UAO_SWHASH_BUCKETS(AOBJ) \
119 (MIN((AOBJ)->u_pages >> UAO_SWHASH_CLUSTER_SHIFT, \
120 UAO_SWHASH_MAXBUCKETS))
121
122
123 /*
124 * uao_swhash_elt: when a hash table is being used, this structure defines
125 * the format of an entry in the bucket list.
126 */
127
128 struct uao_swhash_elt {
129 LIST_ENTRY(uao_swhash_elt) list; /* the hash list */
130 voff_t tag; /* our 'tag' */
131 int count; /* our number of active slots */
132 int slots[UAO_SWHASH_CLUSTER_SIZE]; /* the slots */
133 };
134
135 /*
136 * uao_swhash: the swap hash table structure
137 */
138
139 LIST_HEAD(uao_swhash, uao_swhash_elt);
140
141 /*
142 * uao_swhash_elt_pool: pool of uao_swhash_elt structures
143 * NOTE: Pages for this pool must not come from a pageable kernel map!
144 */
145 POOL_INIT(uao_swhash_elt_pool, sizeof(struct uao_swhash_elt), 0, 0, 0,
146 "uaoeltpl", NULL);
147
148 /*
149 * uvm_aobj: the actual anon-backed uvm_object
150 *
151 * => the uvm_object is at the top of the structure, this allows
152 * (struct uvm_aobj *) == (struct uvm_object *)
153 * => only one of u_swslots and u_swhash is used in any given aobj
154 */
155
156 struct uvm_aobj {
157 struct uvm_object u_obj; /* has: lock, pgops, memq, #pages, #refs */
158 pgoff_t u_pages; /* number of pages in entire object */
159 int u_flags; /* the flags (see uvm_aobj.h) */
160 int *u_swslots; /* array of offset->swapslot mappings */
161 /*
162 * hashtable of offset->swapslot mappings
163 * (u_swhash is an array of bucket heads)
164 */
165 struct uao_swhash *u_swhash;
166 u_long u_swhashmask; /* mask for hashtable */
167 LIST_ENTRY(uvm_aobj) u_list; /* global list of aobjs */
168 };
169
170 /*
171 * uvm_aobj_pool: pool of uvm_aobj structures
172 */
173 POOL_INIT(uvm_aobj_pool, sizeof(struct uvm_aobj), 0, 0, 0, "aobjpl",
174 &pool_allocator_nointr);
175
176 MALLOC_DEFINE(M_UVMAOBJ, "UVM aobj", "UVM aobj and related structures");
177
178 /*
179 * local functions
180 */
181
182 static void uao_free(struct uvm_aobj *);
183 static int uao_get(struct uvm_object *, voff_t, struct vm_page **,
184 int *, int, vm_prot_t, int, int);
185 static boolean_t uao_put(struct uvm_object *, voff_t, voff_t, int);
186
187 #if defined(VMSWAP)
188 static struct uao_swhash_elt *uao_find_swhash_elt
189 (struct uvm_aobj *, int, boolean_t);
190
191 static boolean_t uao_pagein(struct uvm_aobj *, int, int);
192 static boolean_t uao_pagein_page(struct uvm_aobj *, int);
193 static void uao_dropswap_range1(struct uvm_aobj *, voff_t, voff_t);
194 #endif /* defined(VMSWAP) */
195
196 /*
197 * aobj_pager
198 *
199 * note that some functions (e.g. put) are handled elsewhere
200 */
201
202 struct uvm_pagerops aobj_pager = {
203 NULL, /* init */
204 uao_reference, /* reference */
205 uao_detach, /* detach */
206 NULL, /* fault */
207 uao_get, /* get */
208 uao_put, /* flush */
209 };
210
211 /*
212 * uao_list: global list of active aobjs, locked by uao_list_lock
213 */
214
215 static LIST_HEAD(aobjlist, uvm_aobj) uao_list;
216 static struct simplelock uao_list_lock;
217
218 /*
219 * functions
220 */
221
222 /*
223 * hash table/array related functions
224 */
225
226 #if defined(VMSWAP)
227
228 /*
229 * uao_find_swhash_elt: find (or create) a hash table entry for a page
230 * offset.
231 *
232 * => the object should be locked by the caller
233 */
234
235 static struct uao_swhash_elt *
236 uao_find_swhash_elt(struct uvm_aobj *aobj, int pageidx, boolean_t create)
237 {
238 struct uao_swhash *swhash;
239 struct uao_swhash_elt *elt;
240 voff_t page_tag;
241
242 swhash = UAO_SWHASH_HASH(aobj, pageidx);
243 page_tag = UAO_SWHASH_ELT_TAG(pageidx);
244
245 /*
246 * now search the bucket for the requested tag
247 */
248
249 LIST_FOREACH(elt, swhash, list) {
250 if (elt->tag == page_tag) {
251 return elt;
252 }
253 }
254 if (!create) {
255 return NULL;
256 }
257
258 /*
259 * allocate a new entry for the bucket and init/insert it in
260 */
261
262 elt = pool_get(&uao_swhash_elt_pool, PR_NOWAIT);
263 if (elt == NULL) {
264 return NULL;
265 }
266 LIST_INSERT_HEAD(swhash, elt, list);
267 elt->tag = page_tag;
268 elt->count = 0;
269 memset(elt->slots, 0, sizeof(elt->slots));
270 return elt;
271 }
272
273 /*
274 * uao_find_swslot: find the swap slot number for an aobj/pageidx
275 *
276 * => object must be locked by caller
277 */
278
279 int
280 uao_find_swslot(struct uvm_object *uobj, int pageidx)
281 {
282 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj;
283 struct uao_swhash_elt *elt;
284
285 /*
286 * if noswap flag is set, then we never return a slot
287 */
288
289 if (aobj->u_flags & UAO_FLAG_NOSWAP)
290 return(0);
291
292 /*
293 * if hashing, look in hash table.
294 */
295
296 if (UAO_USES_SWHASH(aobj)) {
297 elt = uao_find_swhash_elt(aobj, pageidx, FALSE);
298 if (elt)
299 return(UAO_SWHASH_ELT_PAGESLOT(elt, pageidx));
300 else
301 return(0);
302 }
303
304 /*
305 * otherwise, look in the array
306 */
307
308 return(aobj->u_swslots[pageidx]);
309 }
310
311 /*
312 * uao_set_swslot: set the swap slot for a page in an aobj.
313 *
314 * => setting a slot to zero frees the slot
315 * => object must be locked by caller
316 * => we return the old slot number, or -1 if we failed to allocate
317 * memory to record the new slot number
318 */
319
320 int
321 uao_set_swslot(struct uvm_object *uobj, int pageidx, int slot)
322 {
323 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj;
324 struct uao_swhash_elt *elt;
325 int oldslot;
326 UVMHIST_FUNC("uao_set_swslot"); UVMHIST_CALLED(pdhist);
327 UVMHIST_LOG(pdhist, "aobj %p pageidx %d slot %d",
328 aobj, pageidx, slot, 0);
329
330 /*
331 * if noswap flag is set, then we can't set a non-zero slot.
332 */
333
334 if (aobj->u_flags & UAO_FLAG_NOSWAP) {
335 if (slot == 0)
336 return(0);
337
338 printf("uao_set_swslot: uobj = %p\n", uobj);
339 panic("uao_set_swslot: NOSWAP object");
340 }
341
342 /*
343 * are we using a hash table? if so, add it in the hash.
344 */
345
346 if (UAO_USES_SWHASH(aobj)) {
347
348 /*
349 * Avoid allocating an entry just to free it again if
350 * the page had not swap slot in the first place, and
351 * we are freeing.
352 */
353
354 elt = uao_find_swhash_elt(aobj, pageidx, slot != 0);
355 if (elt == NULL) {
356 return slot ? -1 : 0;
357 }
358
359 oldslot = UAO_SWHASH_ELT_PAGESLOT(elt, pageidx);
360 UAO_SWHASH_ELT_PAGESLOT(elt, pageidx) = slot;
361
362 /*
363 * now adjust the elt's reference counter and free it if we've
364 * dropped it to zero.
365 */
366
367 if (slot) {
368 if (oldslot == 0)
369 elt->count++;
370 } else {
371 if (oldslot)
372 elt->count--;
373
374 if (elt->count == 0) {
375 LIST_REMOVE(elt, list);
376 pool_put(&uao_swhash_elt_pool, elt);
377 }
378 }
379 } else {
380 /* we are using an array */
381 oldslot = aobj->u_swslots[pageidx];
382 aobj->u_swslots[pageidx] = slot;
383 }
384 return (oldslot);
385 }
386
387 #endif /* defined(VMSWAP) */
388
389 /*
390 * end of hash/array functions
391 */
392
393 /*
394 * uao_free: free all resources held by an aobj, and then free the aobj
395 *
396 * => the aobj should be dead
397 */
398
399 static void
400 uao_free(struct uvm_aobj *aobj)
401 {
402 int swpgonlydelta = 0;
403
404 #if defined(VMSWAP)
405 uao_dropswap_range1(aobj, 0, 0);
406 #endif /* defined(VMSWAP) */
407
408 simple_unlock(&aobj->u_obj.vmobjlock);
409
410 #if defined(VMSWAP)
411 if (UAO_USES_SWHASH(aobj)) {
412
413 /*
414 * free the hash table itself.
415 */
416
417 free(aobj->u_swhash, M_UVMAOBJ);
418 } else {
419
420 /*
421 * free the array itsself.
422 */
423
424 free(aobj->u_swslots, M_UVMAOBJ);
425 }
426 #endif /* defined(VMSWAP) */
427
428 /*
429 * finally free the aobj itself
430 */
431
432 pool_put(&uvm_aobj_pool, aobj);
433
434 /*
435 * adjust the counter of pages only in swap for all
436 * the swap slots we've freed.
437 */
438
439 if (swpgonlydelta > 0) {
440 simple_lock(&uvm.swap_data_lock);
441 KASSERT(uvmexp.swpgonly >= swpgonlydelta);
442 uvmexp.swpgonly -= swpgonlydelta;
443 simple_unlock(&uvm.swap_data_lock);
444 }
445 }
446
447 /*
448 * pager functions
449 */
450
451 /*
452 * uao_create: create an aobj of the given size and return its uvm_object.
453 *
454 * => for normal use, flags are always zero
455 * => for the kernel object, the flags are:
456 * UAO_FLAG_KERNOBJ - allocate the kernel object (can only happen once)
457 * UAO_FLAG_KERNSWAP - enable swapping of kernel object (" ")
458 */
459
460 struct uvm_object *
461 uao_create(vsize_t size, int flags)
462 {
463 static struct uvm_aobj kernel_object_store;
464 static int kobj_alloced = 0;
465 pgoff_t pages = round_page(size) >> PAGE_SHIFT;
466 struct uvm_aobj *aobj;
467 int refs;
468
469 /*
470 * malloc a new aobj unless we are asked for the kernel object
471 */
472
473 if (flags & UAO_FLAG_KERNOBJ) {
474 KASSERT(!kobj_alloced);
475 aobj = &kernel_object_store;
476 aobj->u_pages = pages;
477 aobj->u_flags = UAO_FLAG_NOSWAP;
478 refs = UVM_OBJ_KERN;
479 kobj_alloced = UAO_FLAG_KERNOBJ;
480 } else if (flags & UAO_FLAG_KERNSWAP) {
481 KASSERT(kobj_alloced == UAO_FLAG_KERNOBJ);
482 aobj = &kernel_object_store;
483 kobj_alloced = UAO_FLAG_KERNSWAP;
484 refs = 0xdeadbeaf; /* XXX: gcc */
485 } else {
486 aobj = pool_get(&uvm_aobj_pool, PR_WAITOK);
487 aobj->u_pages = pages;
488 aobj->u_flags = 0;
489 refs = 1;
490 }
491
492 /*
493 * allocate hash/array if necessary
494 *
495 * note: in the KERNSWAP case no need to worry about locking since
496 * we are still booting we should be the only thread around.
497 */
498
499 if (flags == 0 || (flags & UAO_FLAG_KERNSWAP) != 0) {
500 #if defined(VMSWAP)
501 int mflags = (flags & UAO_FLAG_KERNSWAP) != 0 ?
502 M_NOWAIT : M_WAITOK;
503
504 /* allocate hash table or array depending on object size */
505 if (UAO_USES_SWHASH(aobj)) {
506 aobj->u_swhash = hashinit(UAO_SWHASH_BUCKETS(aobj),
507 HASH_LIST, M_UVMAOBJ, mflags, &aobj->u_swhashmask);
508 if (aobj->u_swhash == NULL)
509 panic("uao_create: hashinit swhash failed");
510 } else {
511 aobj->u_swslots = malloc(pages * sizeof(int),
512 M_UVMAOBJ, mflags);
513 if (aobj->u_swslots == NULL)
514 panic("uao_create: malloc swslots failed");
515 memset(aobj->u_swslots, 0, pages * sizeof(int));
516 }
517 #endif /* defined(VMSWAP) */
518
519 if (flags) {
520 aobj->u_flags &= ~UAO_FLAG_NOSWAP; /* clear noswap */
521 return(&aobj->u_obj);
522 }
523 }
524
525 /*
526 * init aobj fields
527 */
528
529 UVM_OBJ_INIT(&aobj->u_obj, &aobj_pager, refs);
530
531 /*
532 * now that aobj is ready, add it to the global list
533 */
534
535 simple_lock(&uao_list_lock);
536 LIST_INSERT_HEAD(&uao_list, aobj, u_list);
537 simple_unlock(&uao_list_lock);
538 return(&aobj->u_obj);
539 }
540
541
542
543 /*
544 * uao_init: set up aobj pager subsystem
545 *
546 * => called at boot time from uvm_pager_init()
547 */
548
549 void
550 uao_init(void)
551 {
552 static int uao_initialized;
553
554 if (uao_initialized)
555 return;
556 uao_initialized = TRUE;
557 LIST_INIT(&uao_list);
558 simple_lock_init(&uao_list_lock);
559 }
560
561 /*
562 * uao_reference: add a ref to an aobj
563 *
564 * => aobj must be unlocked
565 * => just lock it and call the locked version
566 */
567
568 void
569 uao_reference(struct uvm_object *uobj)
570 {
571 simple_lock(&uobj->vmobjlock);
572 uao_reference_locked(uobj);
573 simple_unlock(&uobj->vmobjlock);
574 }
575
576 /*
577 * uao_reference_locked: add a ref to an aobj that is already locked
578 *
579 * => aobj must be locked
580 * this needs to be separate from the normal routine
581 * since sometimes we need to add a reference to an aobj when
582 * it's already locked.
583 */
584
585 void
586 uao_reference_locked(struct uvm_object *uobj)
587 {
588 UVMHIST_FUNC("uao_reference"); UVMHIST_CALLED(maphist);
589
590 /*
591 * kernel_object already has plenty of references, leave it alone.
592 */
593
594 if (UVM_OBJ_IS_KERN_OBJECT(uobj))
595 return;
596
597 uobj->uo_refs++;
598 UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)",
599 uobj, uobj->uo_refs,0,0);
600 }
601
602 /*
603 * uao_detach: drop a reference to an aobj
604 *
605 * => aobj must be unlocked
606 * => just lock it and call the locked version
607 */
608
609 void
610 uao_detach(struct uvm_object *uobj)
611 {
612 simple_lock(&uobj->vmobjlock);
613 uao_detach_locked(uobj);
614 }
615
616 /*
617 * uao_detach_locked: drop a reference to an aobj
618 *
619 * => aobj must be locked, and is unlocked (or freed) upon return.
620 * this needs to be separate from the normal routine
621 * since sometimes we need to detach from an aobj when
622 * it's already locked.
623 */
624
625 void
626 uao_detach_locked(struct uvm_object *uobj)
627 {
628 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj;
629 struct vm_page *pg;
630 UVMHIST_FUNC("uao_detach"); UVMHIST_CALLED(maphist);
631
632 /*
633 * detaching from kernel_object is a noop.
634 */
635
636 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) {
637 simple_unlock(&uobj->vmobjlock);
638 return;
639 }
640
641 UVMHIST_LOG(maphist," (uobj=0x%x) ref=%d", uobj,uobj->uo_refs,0,0);
642 uobj->uo_refs--;
643 if (uobj->uo_refs) {
644 simple_unlock(&uobj->vmobjlock);
645 UVMHIST_LOG(maphist, "<- done (rc>0)", 0,0,0,0);
646 return;
647 }
648
649 /*
650 * remove the aobj from the global list.
651 */
652
653 simple_lock(&uao_list_lock);
654 LIST_REMOVE(aobj, u_list);
655 simple_unlock(&uao_list_lock);
656
657 /*
658 * free all the pages left in the aobj. for each page,
659 * when the page is no longer busy (and thus after any disk i/o that
660 * it's involved in is complete), release any swap resources and
661 * free the page itself.
662 */
663
664 uvm_lock_pageq();
665 while ((pg = TAILQ_FIRST(&uobj->memq)) != NULL) {
666 pmap_page_protect(pg, VM_PROT_NONE);
667 if (pg->flags & PG_BUSY) {
668 pg->flags |= PG_WANTED;
669 uvm_unlock_pageq();
670 UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, FALSE,
671 "uao_det", 0);
672 simple_lock(&uobj->vmobjlock);
673 uvm_lock_pageq();
674 continue;
675 }
676 uao_dropswap(&aobj->u_obj, pg->offset >> PAGE_SHIFT);
677 uvm_pagefree(pg);
678 }
679 uvm_unlock_pageq();
680
681 /*
682 * finally, free the aobj itself.
683 */
684
685 uao_free(aobj);
686 }
687
688 /*
689 * uao_put: flush pages out of a uvm object
690 *
691 * => object should be locked by caller. we may _unlock_ the object
692 * if (and only if) we need to clean a page (PGO_CLEANIT).
693 * XXXJRT Currently, however, we don't. In the case of cleaning
694 * XXXJRT a page, we simply just deactivate it. Should probably
695 * XXXJRT handle this better, in the future (although "flushing"
696 * XXXJRT anonymous memory isn't terribly important).
697 * => if PGO_CLEANIT is not set, then we will neither unlock the object
698 * or block.
699 * => if PGO_ALLPAGE is set, then all pages in the object are valid targets
700 * for flushing.
701 * => NOTE: we rely on the fact that the object's memq is a TAILQ and
702 * that new pages are inserted on the tail end of the list. thus,
703 * we can make a complete pass through the object in one go by starting
704 * at the head and working towards the tail (new pages are put in
705 * front of us).
706 * => NOTE: we are allowed to lock the page queues, so the caller
707 * must not be holding the lock on them [e.g. pagedaemon had
708 * better not call us with the queues locked]
709 * => we return TRUE unless we encountered some sort of I/O error
710 * XXXJRT currently never happens, as we never directly initiate
711 * XXXJRT I/O
712 *
713 * note on page traversal:
714 * we can traverse the pages in an object either by going down the
715 * linked list in "uobj->memq", or we can go over the address range
716 * by page doing hash table lookups for each address. depending
717 * on how many pages are in the object it may be cheaper to do one
718 * or the other. we set "by_list" to true if we are using memq.
719 * if the cost of a hash lookup was equal to the cost of the list
720 * traversal we could compare the number of pages in the start->stop
721 * range to the total number of pages in the object. however, it
722 * seems that a hash table lookup is more expensive than the linked
723 * list traversal, so we multiply the number of pages in the
724 * start->stop range by a penalty which we define below.
725 */
726
727 static int
728 uao_put(struct uvm_object *uobj, voff_t start, voff_t stop, int flags)
729 {
730 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj;
731 struct vm_page *pg, *nextpg, curmp, endmp;
732 boolean_t by_list;
733 voff_t curoff;
734 UVMHIST_FUNC("uao_put"); UVMHIST_CALLED(maphist);
735
736 curoff = 0;
737 if (flags & PGO_ALLPAGES) {
738 start = 0;
739 stop = aobj->u_pages << PAGE_SHIFT;
740 by_list = TRUE; /* always go by the list */
741 } else {
742 start = trunc_page(start);
743 if (stop == 0) {
744 stop = aobj->u_pages << PAGE_SHIFT;
745 } else {
746 stop = round_page(stop);
747 }
748 if (stop > (aobj->u_pages << PAGE_SHIFT)) {
749 printf("uao_flush: strange, got an out of range "
750 "flush (fixed)\n");
751 stop = aobj->u_pages << PAGE_SHIFT;
752 }
753 by_list = (uobj->uo_npages <=
754 ((stop - start) >> PAGE_SHIFT) * UVM_PAGE_HASH_PENALTY);
755 }
756 UVMHIST_LOG(maphist,
757 " flush start=0x%lx, stop=0x%x, by_list=%d, flags=0x%x",
758 start, stop, by_list, flags);
759
760 /*
761 * Don't need to do any work here if we're not freeing
762 * or deactivating pages.
763 */
764
765 if ((flags & (PGO_DEACTIVATE|PGO_FREE)) == 0) {
766 simple_unlock(&uobj->vmobjlock);
767 return 0;
768 }
769
770 /*
771 * Initialize the marker pages. See the comment in
772 * genfs_putpages() also.
773 */
774
775 curmp.uobject = uobj;
776 curmp.offset = (voff_t)-1;
777 curmp.flags = PG_BUSY;
778 endmp.uobject = uobj;
779 endmp.offset = (voff_t)-1;
780 endmp.flags = PG_BUSY;
781
782 /*
783 * now do it. note: we must update nextpg in the body of loop or we
784 * will get stuck. we need to use nextpg if we'll traverse the list
785 * because we may free "pg" before doing the next loop.
786 */
787
788 if (by_list) {
789 TAILQ_INSERT_TAIL(&uobj->memq, &endmp, listq);
790 nextpg = TAILQ_FIRST(&uobj->memq);
791 PHOLD(curlwp);
792 } else {
793 curoff = start;
794 nextpg = NULL; /* Quell compiler warning */
795 }
796
797 uvm_lock_pageq();
798
799 /* locked: both page queues and uobj */
800 for (;;) {
801 if (by_list) {
802 pg = nextpg;
803 if (pg == &endmp)
804 break;
805 nextpg = TAILQ_NEXT(pg, listq);
806 if (pg->offset < start || pg->offset >= stop)
807 continue;
808 } else {
809 if (curoff < stop) {
810 pg = uvm_pagelookup(uobj, curoff);
811 curoff += PAGE_SIZE;
812 } else
813 break;
814 if (pg == NULL)
815 continue;
816 }
817 switch (flags & (PGO_CLEANIT|PGO_FREE|PGO_DEACTIVATE)) {
818
819 /*
820 * XXX In these first 3 cases, we always just
821 * XXX deactivate the page. We may want to
822 * XXX handle the different cases more specifically
823 * XXX in the future.
824 */
825
826 case PGO_CLEANIT|PGO_FREE:
827 case PGO_CLEANIT|PGO_DEACTIVATE:
828 case PGO_DEACTIVATE:
829 deactivate_it:
830 /* skip the page if it's loaned or wired */
831 if (pg->loan_count != 0 || pg->wire_count != 0)
832 continue;
833
834 /* ...and deactivate the page. */
835 pmap_clear_reference(pg);
836 uvm_pagedeactivate(pg);
837 continue;
838
839 case PGO_FREE:
840
841 /*
842 * If there are multiple references to
843 * the object, just deactivate the page.
844 */
845
846 if (uobj->uo_refs > 1)
847 goto deactivate_it;
848
849 /*
850 * wait and try again if the page is busy.
851 * otherwise free the swap slot and the page.
852 */
853
854 pmap_page_protect(pg, VM_PROT_NONE);
855 if (pg->flags & PG_BUSY) {
856 if (by_list) {
857 TAILQ_INSERT_BEFORE(pg, &curmp, listq);
858 }
859 pg->flags |= PG_WANTED;
860 uvm_unlock_pageq();
861 UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, 0,
862 "uao_put", 0);
863 simple_lock(&uobj->vmobjlock);
864 uvm_lock_pageq();
865 if (by_list) {
866 nextpg = TAILQ_NEXT(&curmp, listq);
867 TAILQ_REMOVE(&uobj->memq, &curmp,
868 listq);
869 } else
870 curoff -= PAGE_SIZE;
871 continue;
872 }
873
874 /*
875 * freeing swapslot here is not strictly necessary.
876 * however, leaving it here doesn't save much
877 * because we need to update swap accounting anyway.
878 */
879
880 uao_dropswap(uobj, pg->offset >> PAGE_SHIFT);
881 uvm_pagefree(pg);
882 continue;
883 }
884 }
885 uvm_unlock_pageq();
886 if (by_list) {
887 TAILQ_REMOVE(&uobj->memq, &endmp, listq);
888 PRELE(curlwp);
889 }
890 simple_unlock(&uobj->vmobjlock);
891 return 0;
892 }
893
894 /*
895 * uao_get: fetch me a page
896 *
897 * we have three cases:
898 * 1: page is resident -> just return the page.
899 * 2: page is zero-fill -> allocate a new page and zero it.
900 * 3: page is swapped out -> fetch the page from swap.
901 *
902 * cases 1 and 2 can be handled with PGO_LOCKED, case 3 cannot.
903 * so, if the "center" page hits case 3 (or any page, with PGO_ALLPAGES),
904 * then we will need to return EBUSY.
905 *
906 * => prefer map unlocked (not required)
907 * => object must be locked! we will _unlock_ it before starting any I/O.
908 * => flags: PGO_ALLPAGES: get all of the pages
909 * PGO_LOCKED: fault data structures are locked
910 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx]
911 * => NOTE: caller must check for released pages!!
912 */
913
914 static int
915 uao_get(struct uvm_object *uobj, voff_t offset, struct vm_page **pps,
916 int *npagesp, int centeridx, vm_prot_t access_type, int advice, int flags)
917 {
918 #if defined(VMSWAP)
919 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj;
920 #endif /* defined(VMSWAP) */
921 voff_t current_offset;
922 struct vm_page *ptmp = NULL; /* Quell compiler warning */
923 int lcv, gotpages, maxpages, swslot, pageidx;
924 boolean_t done;
925 UVMHIST_FUNC("uao_get"); UVMHIST_CALLED(pdhist);
926
927 UVMHIST_LOG(pdhist, "aobj=%p offset=%d, flags=%d",
928 (struct uvm_aobj *)uobj, offset, flags,0);
929
930 /*
931 * get number of pages
932 */
933
934 maxpages = *npagesp;
935
936 /*
937 * step 1: handled the case where fault data structures are locked.
938 */
939
940 if (flags & PGO_LOCKED) {
941
942 /*
943 * step 1a: get pages that are already resident. only do
944 * this if the data structures are locked (i.e. the first
945 * time through).
946 */
947
948 done = TRUE; /* be optimistic */
949 gotpages = 0; /* # of pages we got so far */
950 for (lcv = 0, current_offset = offset ; lcv < maxpages ;
951 lcv++, current_offset += PAGE_SIZE) {
952 /* do we care about this page? if not, skip it */
953 if (pps[lcv] == PGO_DONTCARE)
954 continue;
955 ptmp = uvm_pagelookup(uobj, current_offset);
956
957 /*
958 * if page is new, attempt to allocate the page,
959 * zero-fill'd.
960 */
961
962 if (ptmp == NULL && uao_find_swslot(&aobj->u_obj,
963 current_offset >> PAGE_SHIFT) == 0) {
964 ptmp = uvm_pagealloc(uobj, current_offset,
965 NULL, UVM_PGA_ZERO);
966 if (ptmp) {
967 /* new page */
968 ptmp->flags &= ~(PG_FAKE);
969 ptmp->pqflags |= PQ_AOBJ;
970 goto gotpage;
971 }
972 }
973
974 /*
975 * to be useful must get a non-busy page
976 */
977
978 if (ptmp == NULL || (ptmp->flags & PG_BUSY) != 0) {
979 if (lcv == centeridx ||
980 (flags & PGO_ALLPAGES) != 0)
981 /* need to do a wait or I/O! */
982 done = FALSE;
983 continue;
984 }
985
986 /*
987 * useful page: busy/lock it and plug it in our
988 * result array
989 */
990
991 /* caller must un-busy this page */
992 ptmp->flags |= PG_BUSY;
993 UVM_PAGE_OWN(ptmp, "uao_get1");
994 gotpage:
995 pps[lcv] = ptmp;
996 gotpages++;
997 }
998
999 /*
1000 * step 1b: now we've either done everything needed or we
1001 * to unlock and do some waiting or I/O.
1002 */
1003
1004 UVMHIST_LOG(pdhist, "<- done (done=%d)", done, 0,0,0);
1005 *npagesp = gotpages;
1006 if (done)
1007 return 0;
1008 else
1009 return EBUSY;
1010 }
1011
1012 /*
1013 * step 2: get non-resident or busy pages.
1014 * object is locked. data structures are unlocked.
1015 */
1016
1017 if ((flags & PGO_SYNCIO) == 0) {
1018 goto done;
1019 }
1020
1021 for (lcv = 0, current_offset = offset ; lcv < maxpages ;
1022 lcv++, current_offset += PAGE_SIZE) {
1023
1024 /*
1025 * - skip over pages we've already gotten or don't want
1026 * - skip over pages we don't _have_ to get
1027 */
1028
1029 if (pps[lcv] != NULL ||
1030 (lcv != centeridx && (flags & PGO_ALLPAGES) == 0))
1031 continue;
1032
1033 pageidx = current_offset >> PAGE_SHIFT;
1034
1035 /*
1036 * we have yet to locate the current page (pps[lcv]). we
1037 * first look for a page that is already at the current offset.
1038 * if we find a page, we check to see if it is busy or
1039 * released. if that is the case, then we sleep on the page
1040 * until it is no longer busy or released and repeat the lookup.
1041 * if the page we found is neither busy nor released, then we
1042 * busy it (so we own it) and plug it into pps[lcv]. this
1043 * 'break's the following while loop and indicates we are
1044 * ready to move on to the next page in the "lcv" loop above.
1045 *
1046 * if we exit the while loop with pps[lcv] still set to NULL,
1047 * then it means that we allocated a new busy/fake/clean page
1048 * ptmp in the object and we need to do I/O to fill in the data.
1049 */
1050
1051 /* top of "pps" while loop */
1052 while (pps[lcv] == NULL) {
1053 /* look for a resident page */
1054 ptmp = uvm_pagelookup(uobj, current_offset);
1055
1056 /* not resident? allocate one now (if we can) */
1057 if (ptmp == NULL) {
1058
1059 ptmp = uvm_pagealloc(uobj, current_offset,
1060 NULL, 0);
1061
1062 /* out of RAM? */
1063 if (ptmp == NULL) {
1064 simple_unlock(&uobj->vmobjlock);
1065 UVMHIST_LOG(pdhist,
1066 "sleeping, ptmp == NULL\n",0,0,0,0);
1067 uvm_wait("uao_getpage");
1068 simple_lock(&uobj->vmobjlock);
1069 continue;
1070 }
1071
1072 /*
1073 * safe with PQ's unlocked: because we just
1074 * alloc'd the page
1075 */
1076
1077 ptmp->pqflags |= PQ_AOBJ;
1078
1079 /*
1080 * got new page ready for I/O. break pps while
1081 * loop. pps[lcv] is still NULL.
1082 */
1083
1084 break;
1085 }
1086
1087 /* page is there, see if we need to wait on it */
1088 if ((ptmp->flags & PG_BUSY) != 0) {
1089 ptmp->flags |= PG_WANTED;
1090 UVMHIST_LOG(pdhist,
1091 "sleeping, ptmp->flags 0x%x\n",
1092 ptmp->flags,0,0,0);
1093 UVM_UNLOCK_AND_WAIT(ptmp, &uobj->vmobjlock,
1094 FALSE, "uao_get", 0);
1095 simple_lock(&uobj->vmobjlock);
1096 continue;
1097 }
1098
1099 /*
1100 * if we get here then the page has become resident and
1101 * unbusy between steps 1 and 2. we busy it now (so we
1102 * own it) and set pps[lcv] (so that we exit the while
1103 * loop).
1104 */
1105
1106 /* we own it, caller must un-busy */
1107 ptmp->flags |= PG_BUSY;
1108 UVM_PAGE_OWN(ptmp, "uao_get2");
1109 pps[lcv] = ptmp;
1110 }
1111
1112 /*
1113 * if we own the valid page at the correct offset, pps[lcv] will
1114 * point to it. nothing more to do except go to the next page.
1115 */
1116
1117 if (pps[lcv])
1118 continue; /* next lcv */
1119
1120 /*
1121 * we have a "fake/busy/clean" page that we just allocated.
1122 * do the needed "i/o", either reading from swap or zeroing.
1123 */
1124
1125 swslot = uao_find_swslot(&aobj->u_obj, pageidx);
1126
1127 /*
1128 * just zero the page if there's nothing in swap.
1129 */
1130
1131 if (swslot == 0) {
1132
1133 /*
1134 * page hasn't existed before, just zero it.
1135 */
1136
1137 uvm_pagezero(ptmp);
1138 } else {
1139 #if defined(VMSWAP)
1140 int error;
1141
1142 UVMHIST_LOG(pdhist, "pagein from swslot %d",
1143 swslot, 0,0,0);
1144
1145 /*
1146 * page in the swapped-out page.
1147 * unlock object for i/o, relock when done.
1148 */
1149
1150 simple_unlock(&uobj->vmobjlock);
1151 error = uvm_swap_get(ptmp, swslot, PGO_SYNCIO);
1152 simple_lock(&uobj->vmobjlock);
1153
1154 /*
1155 * I/O done. check for errors.
1156 */
1157
1158 if (error != 0) {
1159 UVMHIST_LOG(pdhist, "<- done (error=%d)",
1160 error,0,0,0);
1161 if (ptmp->flags & PG_WANTED)
1162 wakeup(ptmp);
1163
1164 /*
1165 * remove the swap slot from the aobj
1166 * and mark the aobj as having no real slot.
1167 * don't free the swap slot, thus preventing
1168 * it from being used again.
1169 */
1170
1171 swslot = uao_set_swslot(&aobj->u_obj, pageidx,
1172 SWSLOT_BAD);
1173 if (swslot > 0) {
1174 uvm_swap_markbad(swslot, 1);
1175 }
1176
1177 uvm_lock_pageq();
1178 uvm_pagefree(ptmp);
1179 uvm_unlock_pageq();
1180 simple_unlock(&uobj->vmobjlock);
1181 return error;
1182 }
1183 #else /* defined(VMSWAP) */
1184 panic("%s: pagein", __func__);
1185 #endif /* defined(VMSWAP) */
1186 }
1187
1188 if ((access_type & VM_PROT_WRITE) == 0) {
1189 ptmp->flags |= PG_CLEAN;
1190 pmap_clear_modify(ptmp);
1191 }
1192
1193 /*
1194 * we got the page! clear the fake flag (indicates valid
1195 * data now in page) and plug into our result array. note
1196 * that page is still busy.
1197 *
1198 * it is the callers job to:
1199 * => check if the page is released
1200 * => unbusy the page
1201 * => activate the page
1202 */
1203
1204 ptmp->flags &= ~PG_FAKE;
1205 pps[lcv] = ptmp;
1206 }
1207
1208 /*
1209 * finally, unlock object and return.
1210 */
1211
1212 done:
1213 simple_unlock(&uobj->vmobjlock);
1214 UVMHIST_LOG(pdhist, "<- done (OK)",0,0,0,0);
1215 return 0;
1216 }
1217
1218 #if defined(VMSWAP)
1219
1220 /*
1221 * uao_dropswap: release any swap resources from this aobj page.
1222 *
1223 * => aobj must be locked or have a reference count of 0.
1224 */
1225
1226 void
1227 uao_dropswap(struct uvm_object *uobj, int pageidx)
1228 {
1229 int slot;
1230
1231 slot = uao_set_swslot(uobj, pageidx, 0);
1232 if (slot) {
1233 uvm_swap_free(slot, 1);
1234 }
1235 }
1236
1237 /*
1238 * page in every page in every aobj that is paged-out to a range of swslots.
1239 *
1240 * => nothing should be locked.
1241 * => returns TRUE if pagein was aborted due to lack of memory.
1242 */
1243
1244 boolean_t
1245 uao_swap_off(int startslot, int endslot)
1246 {
1247 struct uvm_aobj *aobj, *nextaobj;
1248 boolean_t rv;
1249
1250 /*
1251 * walk the list of all aobjs.
1252 */
1253
1254 restart:
1255 simple_lock(&uao_list_lock);
1256 for (aobj = LIST_FIRST(&uao_list);
1257 aobj != NULL;
1258 aobj = nextaobj) {
1259
1260 /*
1261 * try to get the object lock, start all over if we fail.
1262 * most of the time we'll get the aobj lock,
1263 * so this should be a rare case.
1264 */
1265
1266 if (!simple_lock_try(&aobj->u_obj.vmobjlock)) {
1267 simple_unlock(&uao_list_lock);
1268 goto restart;
1269 }
1270
1271 /*
1272 * add a ref to the aobj so it doesn't disappear
1273 * while we're working.
1274 */
1275
1276 uao_reference_locked(&aobj->u_obj);
1277
1278 /*
1279 * now it's safe to unlock the uao list.
1280 */
1281
1282 simple_unlock(&uao_list_lock);
1283
1284 /*
1285 * page in any pages in the swslot range.
1286 * if there's an error, abort and return the error.
1287 */
1288
1289 rv = uao_pagein(aobj, startslot, endslot);
1290 if (rv) {
1291 uao_detach_locked(&aobj->u_obj);
1292 return rv;
1293 }
1294
1295 /*
1296 * we're done with this aobj.
1297 * relock the list and drop our ref on the aobj.
1298 */
1299
1300 simple_lock(&uao_list_lock);
1301 nextaobj = LIST_NEXT(aobj, u_list);
1302 uao_detach_locked(&aobj->u_obj);
1303 }
1304
1305 /*
1306 * done with traversal, unlock the list
1307 */
1308 simple_unlock(&uao_list_lock);
1309 return FALSE;
1310 }
1311
1312
1313 /*
1314 * page in any pages from aobj in the given range.
1315 *
1316 * => aobj must be locked and is returned locked.
1317 * => returns TRUE if pagein was aborted due to lack of memory.
1318 */
1319 static boolean_t
1320 uao_pagein(struct uvm_aobj *aobj, int startslot, int endslot)
1321 {
1322 boolean_t rv;
1323
1324 if (UAO_USES_SWHASH(aobj)) {
1325 struct uao_swhash_elt *elt;
1326 int buck;
1327
1328 restart:
1329 for (buck = aobj->u_swhashmask; buck >= 0; buck--) {
1330 for (elt = LIST_FIRST(&aobj->u_swhash[buck]);
1331 elt != NULL;
1332 elt = LIST_NEXT(elt, list)) {
1333 int i;
1334
1335 for (i = 0; i < UAO_SWHASH_CLUSTER_SIZE; i++) {
1336 int slot = elt->slots[i];
1337
1338 /*
1339 * if the slot isn't in range, skip it.
1340 */
1341
1342 if (slot < startslot ||
1343 slot >= endslot) {
1344 continue;
1345 }
1346
1347 /*
1348 * process the page,
1349 * the start over on this object
1350 * since the swhash elt
1351 * may have been freed.
1352 */
1353
1354 rv = uao_pagein_page(aobj,
1355 UAO_SWHASH_ELT_PAGEIDX_BASE(elt) + i);
1356 if (rv) {
1357 return rv;
1358 }
1359 goto restart;
1360 }
1361 }
1362 }
1363 } else {
1364 int i;
1365
1366 for (i = 0; i < aobj->u_pages; i++) {
1367 int slot = aobj->u_swslots[i];
1368
1369 /*
1370 * if the slot isn't in range, skip it
1371 */
1372
1373 if (slot < startslot || slot >= endslot) {
1374 continue;
1375 }
1376
1377 /*
1378 * process the page.
1379 */
1380
1381 rv = uao_pagein_page(aobj, i);
1382 if (rv) {
1383 return rv;
1384 }
1385 }
1386 }
1387
1388 return FALSE;
1389 }
1390
1391 /*
1392 * page in a page from an aobj. used for swap_off.
1393 * returns TRUE if pagein was aborted due to lack of memory.
1394 *
1395 * => aobj must be locked and is returned locked.
1396 */
1397
1398 static boolean_t
1399 uao_pagein_page(struct uvm_aobj *aobj, int pageidx)
1400 {
1401 struct vm_page *pg;
1402 int rv, npages;
1403
1404 pg = NULL;
1405 npages = 1;
1406 /* locked: aobj */
1407 rv = uao_get(&aobj->u_obj, pageidx << PAGE_SHIFT,
1408 &pg, &npages, 0, VM_PROT_READ|VM_PROT_WRITE, 0, PGO_SYNCIO);
1409 /* unlocked: aobj */
1410
1411 /*
1412 * relock and finish up.
1413 */
1414
1415 simple_lock(&aobj->u_obj.vmobjlock);
1416 switch (rv) {
1417 case 0:
1418 break;
1419
1420 case EIO:
1421 case ERESTART:
1422
1423 /*
1424 * nothing more to do on errors.
1425 * ERESTART can only mean that the anon was freed,
1426 * so again there's nothing to do.
1427 */
1428
1429 return FALSE;
1430
1431 default:
1432 return TRUE;
1433 }
1434
1435 /*
1436 * ok, we've got the page now.
1437 * mark it as dirty, clear its swslot and un-busy it.
1438 */
1439 uao_dropswap(&aobj->u_obj, pageidx);
1440
1441 /*
1442 * make sure it's on a page queue.
1443 */
1444 uvm_lock_pageq();
1445 if (pg->wire_count == 0)
1446 uvm_pageenqueue(pg);
1447 uvm_unlock_pageq();
1448
1449 if (pg->flags & PG_WANTED) {
1450 wakeup(pg);
1451 }
1452 pg->flags &= ~(PG_WANTED|PG_BUSY|PG_CLEAN|PG_FAKE);
1453 UVM_PAGE_OWN(pg, NULL);
1454
1455 return FALSE;
1456 }
1457
1458 /*
1459 * uao_dropswap_range: drop swapslots in the range.
1460 *
1461 * => aobj must be locked and is returned locked.
1462 * => start is inclusive. end is exclusive.
1463 */
1464
1465 void
1466 uao_dropswap_range(struct uvm_object *uobj, voff_t start, voff_t end)
1467 {
1468 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj;
1469
1470 LOCK_ASSERT(simple_lock_held(&uobj->vmobjlock));
1471
1472 uao_dropswap_range1(aobj, start, end);
1473 }
1474
1475 static void
1476 uao_dropswap_range1(struct uvm_aobj *aobj, voff_t start, voff_t end)
1477 {
1478 int swpgonlydelta = 0;
1479
1480 if (end == 0) {
1481 end = INT64_MAX;
1482 }
1483
1484 if (UAO_USES_SWHASH(aobj)) {
1485 int i, hashbuckets = aobj->u_swhashmask + 1;
1486 voff_t taghi;
1487 voff_t taglo;
1488
1489 taglo = UAO_SWHASH_ELT_TAG(start);
1490 taghi = UAO_SWHASH_ELT_TAG(end);
1491
1492 for (i = 0; i < hashbuckets; i++) {
1493 struct uao_swhash_elt *elt, *next;
1494
1495 for (elt = LIST_FIRST(&aobj->u_swhash[i]);
1496 elt != NULL;
1497 elt = next) {
1498 int startidx, endidx;
1499 int j;
1500
1501 next = LIST_NEXT(elt, list);
1502
1503 if (elt->tag < taglo || taghi < elt->tag) {
1504 continue;
1505 }
1506
1507 if (elt->tag == taglo) {
1508 startidx =
1509 UAO_SWHASH_ELT_PAGESLOT_IDX(start);
1510 } else {
1511 startidx = 0;
1512 }
1513
1514 if (elt->tag == taghi) {
1515 endidx =
1516 UAO_SWHASH_ELT_PAGESLOT_IDX(end);
1517 } else {
1518 endidx = UAO_SWHASH_CLUSTER_SIZE;
1519 }
1520
1521 for (j = startidx; j < endidx; j++) {
1522 int slot = elt->slots[j];
1523
1524 KASSERT(uvm_pagelookup(&aobj->u_obj,
1525 (UAO_SWHASH_ELT_PAGEIDX_BASE(elt)
1526 + j) << PAGE_SHIFT) == NULL);
1527 if (slot > 0) {
1528 uvm_swap_free(slot, 1);
1529 swpgonlydelta++;
1530 KASSERT(elt->count > 0);
1531 elt->slots[j] = 0;
1532 elt->count--;
1533 }
1534 }
1535
1536 if (elt->count == 0) {
1537 LIST_REMOVE(elt, list);
1538 pool_put(&uao_swhash_elt_pool, elt);
1539 }
1540 }
1541 }
1542 } else {
1543 int i;
1544
1545 if (aobj->u_pages < end) {
1546 end = aobj->u_pages;
1547 }
1548 for (i = start; i < end; i++) {
1549 int slot = aobj->u_swslots[i];
1550
1551 if (slot > 0) {
1552 uvm_swap_free(slot, 1);
1553 swpgonlydelta++;
1554 }
1555 }
1556 }
1557
1558 /*
1559 * adjust the counter of pages only in swap for all
1560 * the swap slots we've freed.
1561 */
1562
1563 if (swpgonlydelta > 0) {
1564 simple_lock(&uvm.swap_data_lock);
1565 KASSERT(uvmexp.swpgonly >= swpgonlydelta);
1566 uvmexp.swpgonly -= swpgonlydelta;
1567 simple_unlock(&uvm.swap_data_lock);
1568 }
1569 }
1570
1571 #endif /* defined(VMSWAP) */
Cache object: 13776dbff7a721754f4010865f2ffe91
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