1 /* $NetBSD: uvm_aobj.c,v 1.111 2011/01/25 03:34:29 enami 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 1.111 2011/01/25 03:34:29 enami 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/kernel.h> 54 #include <sys/kmem.h> 55 #include <sys/pool.h> 56 57 #include <uvm/uvm.h> 58 59 /* 60 * an aobj manages anonymous-memory backed uvm_objects. in addition 61 * to keeping the list of resident pages, it also keeps a list of 62 * allocated swap blocks. depending on the size of the aobj this list 63 * of allocated swap blocks is either stored in an array (small objects) 64 * or in a hash table (large objects). 65 */ 66 67 /* 68 * local structures 69 */ 70 71 /* 72 * for hash tables, we break the address space of the aobj into blocks 73 * of UAO_SWHASH_CLUSTER_SIZE pages. we require the cluster size to 74 * be a power of two. 75 */ 76 77 #define UAO_SWHASH_CLUSTER_SHIFT 4 78 #define UAO_SWHASH_CLUSTER_SIZE (1 << UAO_SWHASH_CLUSTER_SHIFT) 79 80 /* get the "tag" for this page index */ 81 #define UAO_SWHASH_ELT_TAG(PAGEIDX) \ 82 ((PAGEIDX) >> UAO_SWHASH_CLUSTER_SHIFT) 83 84 #define UAO_SWHASH_ELT_PAGESLOT_IDX(PAGEIDX) \ 85 ((PAGEIDX) & (UAO_SWHASH_CLUSTER_SIZE - 1)) 86 87 /* given an ELT and a page index, find the swap slot */ 88 #define UAO_SWHASH_ELT_PAGESLOT(ELT, PAGEIDX) \ 89 ((ELT)->slots[UAO_SWHASH_ELT_PAGESLOT_IDX(PAGEIDX)]) 90 91 /* given an ELT, return its pageidx base */ 92 #define UAO_SWHASH_ELT_PAGEIDX_BASE(ELT) \ 93 ((ELT)->tag << UAO_SWHASH_CLUSTER_SHIFT) 94 95 /* 96 * the swhash hash function 97 */ 98 99 #define UAO_SWHASH_HASH(AOBJ, PAGEIDX) \ 100 (&(AOBJ)->u_swhash[(((PAGEIDX) >> UAO_SWHASH_CLUSTER_SHIFT) \ 101 & (AOBJ)->u_swhashmask)]) 102 103 /* 104 * the swhash threshhold determines if we will use an array or a 105 * hash table to store the list of allocated swap blocks. 106 */ 107 108 #define UAO_SWHASH_THRESHOLD (UAO_SWHASH_CLUSTER_SIZE * 4) 109 #define UAO_USES_SWHASH(AOBJ) \ 110 ((AOBJ)->u_pages > UAO_SWHASH_THRESHOLD) /* use hash? */ 111 112 /* 113 * the number of buckets in a swhash, with an upper bound 114 */ 115 116 #define UAO_SWHASH_MAXBUCKETS 256 117 #define UAO_SWHASH_BUCKETS(AOBJ) \ 118 (MIN((AOBJ)->u_pages >> UAO_SWHASH_CLUSTER_SHIFT, \ 119 UAO_SWHASH_MAXBUCKETS)) 120 121 /* 122 * uao_swhash_elt: when a hash table is being used, this structure defines 123 * the format of an entry in the bucket list. 124 */ 125 126 struct uao_swhash_elt { 127 LIST_ENTRY(uao_swhash_elt) list; /* the hash list */ 128 voff_t tag; /* our 'tag' */ 129 int count; /* our number of active slots */ 130 int slots[UAO_SWHASH_CLUSTER_SIZE]; /* the slots */ 131 }; 132 133 /* 134 * uao_swhash: the swap hash table structure 135 */ 136 137 LIST_HEAD(uao_swhash, uao_swhash_elt); 138 139 /* 140 * uao_swhash_elt_pool: pool of uao_swhash_elt structures 141 * NOTE: Pages for this pool must not come from a pageable kernel map! 142 */ 143 static struct pool uao_swhash_elt_pool; 144 145 static struct pool_cache uvm_aobj_cache; 146 147 /* 148 * uvm_aobj: the actual anon-backed uvm_object 149 * 150 * => the uvm_object is at the top of the structure, this allows 151 * (struct uvm_aobj *) == (struct uvm_object *) 152 * => only one of u_swslots and u_swhash is used in any given aobj 153 */ 154 155 struct uvm_aobj { 156 struct uvm_object u_obj; /* has: lock, pgops, memq, #pages, #refs */ 157 pgoff_t u_pages; /* number of pages in entire object */ 158 int u_flags; /* the flags (see uvm_aobj.h) */ 159 int *u_swslots; /* array of offset->swapslot mappings */ 160 /* 161 * hashtable of offset->swapslot mappings 162 * (u_swhash is an array of bucket heads) 163 */ 164 struct uao_swhash *u_swhash; 165 u_long u_swhashmask; /* mask for hashtable */ 166 LIST_ENTRY(uvm_aobj) u_list; /* global list of aobjs */ 167 }; 168 169 /* 170 * local functions 171 */ 172 173 static void uao_free(struct uvm_aobj *); 174 static int uao_get(struct uvm_object *, voff_t, struct vm_page **, 175 int *, int, vm_prot_t, int, int); 176 static int uao_put(struct uvm_object *, voff_t, voff_t, int); 177 178 static void uao_detach_locked(struct uvm_object *); 179 static void uao_reference_locked(struct uvm_object *); 180 181 #if defined(VMSWAP) 182 static struct uao_swhash_elt *uao_find_swhash_elt 183 (struct uvm_aobj *, int, bool); 184 185 static bool uao_pagein(struct uvm_aobj *, int, int); 186 static bool uao_pagein_page(struct uvm_aobj *, int); 187 static void uao_dropswap_range1(struct uvm_aobj *, voff_t, voff_t); 188 #endif /* defined(VMSWAP) */ 189 190 /* 191 * aobj_pager 192 * 193 * note that some functions (e.g. put) are handled elsewhere 194 */ 195 196 const struct uvm_pagerops aobj_pager = { 197 .pgo_reference = uao_reference, 198 .pgo_detach = uao_detach, 199 .pgo_get = uao_get, 200 .pgo_put = uao_put, 201 }; 202 203 /* 204 * uao_list: global list of active aobjs, locked by uao_list_lock 205 */ 206 207 static LIST_HEAD(aobjlist, uvm_aobj) uao_list; 208 static kmutex_t uao_list_lock; 209 210 /* 211 * functions 212 */ 213 214 /* 215 * hash table/array related functions 216 */ 217 218 #if defined(VMSWAP) 219 220 /* 221 * uao_find_swhash_elt: find (or create) a hash table entry for a page 222 * offset. 223 * 224 * => the object should be locked by the caller 225 */ 226 227 static struct uao_swhash_elt * 228 uao_find_swhash_elt(struct uvm_aobj *aobj, int pageidx, bool create) 229 { 230 struct uao_swhash *swhash; 231 struct uao_swhash_elt *elt; 232 voff_t page_tag; 233 234 swhash = UAO_SWHASH_HASH(aobj, pageidx); 235 page_tag = UAO_SWHASH_ELT_TAG(pageidx); 236 237 /* 238 * now search the bucket for the requested tag 239 */ 240 241 LIST_FOREACH(elt, swhash, list) { 242 if (elt->tag == page_tag) { 243 return elt; 244 } 245 } 246 if (!create) { 247 return NULL; 248 } 249 250 /* 251 * allocate a new entry for the bucket and init/insert it in 252 */ 253 254 elt = pool_get(&uao_swhash_elt_pool, PR_NOWAIT); 255 if (elt == NULL) { 256 return NULL; 257 } 258 LIST_INSERT_HEAD(swhash, elt, list); 259 elt->tag = page_tag; 260 elt->count = 0; 261 memset(elt->slots, 0, sizeof(elt->slots)); 262 return elt; 263 } 264 265 /* 266 * uao_find_swslot: find the swap slot number for an aobj/pageidx 267 * 268 * => object must be locked by caller 269 */ 270 271 int 272 uao_find_swslot(struct uvm_object *uobj, int pageidx) 273 { 274 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 275 struct uao_swhash_elt *elt; 276 277 /* 278 * if noswap flag is set, then we never return a slot 279 */ 280 281 if (aobj->u_flags & UAO_FLAG_NOSWAP) 282 return(0); 283 284 /* 285 * if hashing, look in hash table. 286 */ 287 288 if (UAO_USES_SWHASH(aobj)) { 289 elt = uao_find_swhash_elt(aobj, pageidx, false); 290 if (elt) 291 return(UAO_SWHASH_ELT_PAGESLOT(elt, pageidx)); 292 else 293 return(0); 294 } 295 296 /* 297 * otherwise, look in the array 298 */ 299 300 return(aobj->u_swslots[pageidx]); 301 } 302 303 /* 304 * uao_set_swslot: set the swap slot for a page in an aobj. 305 * 306 * => setting a slot to zero frees the slot 307 * => object must be locked by caller 308 * => we return the old slot number, or -1 if we failed to allocate 309 * memory to record the new slot number 310 */ 311 312 int 313 uao_set_swslot(struct uvm_object *uobj, int pageidx, int slot) 314 { 315 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 316 struct uao_swhash_elt *elt; 317 int oldslot; 318 UVMHIST_FUNC("uao_set_swslot"); UVMHIST_CALLED(pdhist); 319 UVMHIST_LOG(pdhist, "aobj %p pageidx %d slot %d", 320 aobj, pageidx, slot, 0); 321 322 KASSERT(mutex_owned(&uobj->vmobjlock) || uobj->uo_refs == 0); 323 324 /* 325 * if noswap flag is set, then we can't set a non-zero slot. 326 */ 327 328 if (aobj->u_flags & UAO_FLAG_NOSWAP) { 329 if (slot == 0) 330 return(0); 331 332 printf("uao_set_swslot: uobj = %p\n", uobj); 333 panic("uao_set_swslot: NOSWAP object"); 334 } 335 336 /* 337 * are we using a hash table? if so, add it in the hash. 338 */ 339 340 if (UAO_USES_SWHASH(aobj)) { 341 342 /* 343 * Avoid allocating an entry just to free it again if 344 * the page had not swap slot in the first place, and 345 * we are freeing. 346 */ 347 348 elt = uao_find_swhash_elt(aobj, pageidx, slot != 0); 349 if (elt == NULL) { 350 return slot ? -1 : 0; 351 } 352 353 oldslot = UAO_SWHASH_ELT_PAGESLOT(elt, pageidx); 354 UAO_SWHASH_ELT_PAGESLOT(elt, pageidx) = slot; 355 356 /* 357 * now adjust the elt's reference counter and free it if we've 358 * dropped it to zero. 359 */ 360 361 if (slot) { 362 if (oldslot == 0) 363 elt->count++; 364 } else { 365 if (oldslot) 366 elt->count--; 367 368 if (elt->count == 0) { 369 LIST_REMOVE(elt, list); 370 pool_put(&uao_swhash_elt_pool, elt); 371 } 372 } 373 } else { 374 /* we are using an array */ 375 oldslot = aobj->u_swslots[pageidx]; 376 aobj->u_swslots[pageidx] = slot; 377 } 378 return (oldslot); 379 } 380 381 #endif /* defined(VMSWAP) */ 382 383 /* 384 * end of hash/array functions 385 */ 386 387 /* 388 * uao_free: free all resources held by an aobj, and then free the aobj 389 * 390 * => the aobj should be dead 391 */ 392 393 static void 394 uao_free(struct uvm_aobj *aobj) 395 { 396 397 #if defined(VMSWAP) 398 uao_dropswap_range1(aobj, 0, 0); 399 #endif /* defined(VMSWAP) */ 400 401 mutex_exit(&aobj->u_obj.vmobjlock); 402 403 #if defined(VMSWAP) 404 if (UAO_USES_SWHASH(aobj)) { 405 406 /* 407 * free the hash table itself. 408 */ 409 410 hashdone(aobj->u_swhash, HASH_LIST, aobj->u_swhashmask); 411 } else { 412 413 /* 414 * free the array itsself. 415 */ 416 417 kmem_free(aobj->u_swslots, aobj->u_pages * sizeof(int)); 418 } 419 #endif /* defined(VMSWAP) */ 420 421 /* 422 * finally free the aobj itself 423 */ 424 425 UVM_OBJ_DESTROY(&aobj->u_obj); 426 pool_cache_put(&uvm_aobj_cache, aobj); 427 } 428 429 /* 430 * pager functions 431 */ 432 433 /* 434 * uao_create: create an aobj of the given size and return its uvm_object. 435 * 436 * => for normal use, flags are always zero 437 * => for the kernel object, the flags are: 438 * UAO_FLAG_KERNOBJ - allocate the kernel object (can only happen once) 439 * UAO_FLAG_KERNSWAP - enable swapping of kernel object (" ") 440 */ 441 442 struct uvm_object * 443 uao_create(vsize_t size, int flags) 444 { 445 static struct uvm_aobj kernel_object_store; 446 static int kobj_alloced = 0; 447 pgoff_t pages = round_page(size) >> PAGE_SHIFT; 448 struct uvm_aobj *aobj; 449 int refs; 450 451 /* 452 * malloc a new aobj unless we are asked for the kernel object 453 */ 454 455 if (flags & UAO_FLAG_KERNOBJ) { 456 KASSERT(!kobj_alloced); 457 aobj = &kernel_object_store; 458 aobj->u_pages = pages; 459 aobj->u_flags = UAO_FLAG_NOSWAP; 460 refs = UVM_OBJ_KERN; 461 kobj_alloced = UAO_FLAG_KERNOBJ; 462 } else if (flags & UAO_FLAG_KERNSWAP) { 463 KASSERT(kobj_alloced == UAO_FLAG_KERNOBJ); 464 aobj = &kernel_object_store; 465 kobj_alloced = UAO_FLAG_KERNSWAP; 466 refs = 0xdeadbeaf; /* XXX: gcc */ 467 } else { 468 aobj = pool_cache_get(&uvm_aobj_cache, PR_WAITOK); 469 aobj->u_pages = pages; 470 aobj->u_flags = 0; 471 refs = 1; 472 } 473 474 /* 475 * allocate hash/array if necessary 476 * 477 * note: in the KERNSWAP case no need to worry about locking since 478 * we are still booting we should be the only thread around. 479 */ 480 481 if (flags == 0 || (flags & UAO_FLAG_KERNSWAP) != 0) { 482 #if defined(VMSWAP) 483 const int kernswap = (flags & UAO_FLAG_KERNSWAP) != 0; 484 485 /* allocate hash table or array depending on object size */ 486 if (UAO_USES_SWHASH(aobj)) { 487 aobj->u_swhash = hashinit(UAO_SWHASH_BUCKETS(aobj), 488 HASH_LIST, kernswap ? false : true, 489 &aobj->u_swhashmask); 490 if (aobj->u_swhash == NULL) 491 panic("uao_create: hashinit swhash failed"); 492 } else { 493 aobj->u_swslots = kmem_zalloc(pages * sizeof(int), 494 kernswap ? KM_NOSLEEP : KM_SLEEP); 495 if (aobj->u_swslots == NULL) 496 panic("uao_create: malloc swslots failed"); 497 } 498 #endif /* defined(VMSWAP) */ 499 500 if (flags) { 501 aobj->u_flags &= ~UAO_FLAG_NOSWAP; /* clear noswap */ 502 return(&aobj->u_obj); 503 } 504 } 505 506 /* 507 * init aobj fields 508 */ 509 510 UVM_OBJ_INIT(&aobj->u_obj, &aobj_pager, refs); 511 512 /* 513 * now that aobj is ready, add it to the global list 514 */ 515 516 mutex_enter(&uao_list_lock); 517 LIST_INSERT_HEAD(&uao_list, aobj, u_list); 518 mutex_exit(&uao_list_lock); 519 return(&aobj->u_obj); 520 } 521 522 523 524 /* 525 * uao_init: set up aobj pager subsystem 526 * 527 * => called at boot time from uvm_pager_init() 528 */ 529 530 void 531 uao_init(void) 532 { 533 static int uao_initialized; 534 535 if (uao_initialized) 536 return; 537 uao_initialized = true; 538 LIST_INIT(&uao_list); 539 mutex_init(&uao_list_lock, MUTEX_DEFAULT, IPL_NONE); 540 pool_cache_bootstrap(&uvm_aobj_cache, sizeof(struct uvm_aobj), 0, 0, 541 0, "aobj", NULL, IPL_NONE, NULL, NULL, NULL); 542 pool_init(&uao_swhash_elt_pool, sizeof(struct uao_swhash_elt), 543 0, 0, 0, "uaoeltpl", NULL, IPL_VM); 544 } 545 546 /* 547 * uao_reference: add a ref to an aobj 548 * 549 * => aobj must be unlocked 550 * => just lock it and call the locked version 551 */ 552 553 void 554 uao_reference(struct uvm_object *uobj) 555 { 556 557 /* 558 * kernel_object already has plenty of references, leave it alone. 559 */ 560 561 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) 562 return; 563 564 mutex_enter(&uobj->vmobjlock); 565 uao_reference_locked(uobj); 566 mutex_exit(&uobj->vmobjlock); 567 } 568 569 /* 570 * uao_reference_locked: add a ref to an aobj that is already locked 571 * 572 * => aobj must be locked 573 * this needs to be separate from the normal routine 574 * since sometimes we need to add a reference to an aobj when 575 * it's already locked. 576 */ 577 578 static void 579 uao_reference_locked(struct uvm_object *uobj) 580 { 581 UVMHIST_FUNC("uao_reference"); UVMHIST_CALLED(maphist); 582 583 /* 584 * kernel_object already has plenty of references, leave it alone. 585 */ 586 587 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) 588 return; 589 590 uobj->uo_refs++; 591 UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)", 592 uobj, uobj->uo_refs,0,0); 593 } 594 595 /* 596 * uao_detach: drop a reference to an aobj 597 * 598 * => aobj must be unlocked 599 * => just lock it and call the locked version 600 */ 601 602 void 603 uao_detach(struct uvm_object *uobj) 604 { 605 606 /* 607 * detaching from kernel_object is a noop. 608 */ 609 610 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) 611 return; 612 613 mutex_enter(&uobj->vmobjlock); 614 uao_detach_locked(uobj); 615 } 616 617 /* 618 * uao_detach_locked: drop a reference to an aobj 619 * 620 * => aobj must be locked, and is unlocked (or freed) upon return. 621 * this needs to be separate from the normal routine 622 * since sometimes we need to detach from an aobj when 623 * it's already locked. 624 */ 625 626 static void 627 uao_detach_locked(struct uvm_object *uobj) 628 { 629 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 630 struct vm_page *pg; 631 UVMHIST_FUNC("uao_detach"); UVMHIST_CALLED(maphist); 632 633 /* 634 * detaching from kernel_object is a noop. 635 */ 636 637 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) { 638 mutex_exit(&uobj->vmobjlock); 639 return; 640 } 641 642 UVMHIST_LOG(maphist," (uobj=0x%x) ref=%d", uobj,uobj->uo_refs,0,0); 643 uobj->uo_refs--; 644 if (uobj->uo_refs) { 645 mutex_exit(&uobj->vmobjlock); 646 UVMHIST_LOG(maphist, "<- done (rc>0)", 0,0,0,0); 647 return; 648 } 649 650 /* 651 * remove the aobj from the global list. 652 */ 653 654 mutex_enter(&uao_list_lock); 655 LIST_REMOVE(aobj, u_list); 656 mutex_exit(&uao_list_lock); 657 658 /* 659 * free all the pages left in the aobj. for each page, 660 * when the page is no longer busy (and thus after any disk i/o that 661 * it's involved in is complete), release any swap resources and 662 * free the page itself. 663 */ 664 665 mutex_enter(&uvm_pageqlock); 666 while ((pg = TAILQ_FIRST(&uobj->memq)) != NULL) { 667 pmap_page_protect(pg, VM_PROT_NONE); 668 if (pg->flags & PG_BUSY) { 669 pg->flags |= PG_WANTED; 670 mutex_exit(&uvm_pageqlock); 671 UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, false, 672 "uao_det", 0); 673 mutex_enter(&uobj->vmobjlock); 674 mutex_enter(&uvm_pageqlock); 675 continue; 676 } 677 uao_dropswap(&aobj->u_obj, pg->offset >> PAGE_SHIFT); 678 uvm_pagefree(pg); 679 } 680 mutex_exit(&uvm_pageqlock); 681 682 /* 683 * finally, free the aobj itself. 684 */ 685 686 uao_free(aobj); 687 } 688 689 /* 690 * uao_put: flush pages out of a uvm object 691 * 692 * => object should be locked by caller. we may _unlock_ the object 693 * if (and only if) we need to clean a page (PGO_CLEANIT). 694 * XXXJRT Currently, however, we don't. In the case of cleaning 695 * XXXJRT a page, we simply just deactivate it. Should probably 696 * XXXJRT handle this better, in the future (although "flushing" 697 * XXXJRT anonymous memory isn't terribly important). 698 * => if PGO_CLEANIT is not set, then we will neither unlock the object 699 * or block. 700 * => if PGO_ALLPAGE is set, then all pages in the object are valid targets 701 * for flushing. 702 * => NOTE: we rely on the fact that the object's memq is a TAILQ and 703 * that new pages are inserted on the tail end of the list. thus, 704 * we can make a complete pass through the object in one go by starting 705 * at the head and working towards the tail (new pages are put in 706 * front of us). 707 * => NOTE: we are allowed to lock the page queues, so the caller 708 * must not be holding the lock on them [e.g. pagedaemon had 709 * better not call us with the queues locked] 710 * => we return 0 unless we encountered some sort of I/O error 711 * XXXJRT currently never happens, as we never directly initiate 712 * XXXJRT I/O 713 * 714 * note on page traversal: 715 * we can traverse the pages in an object either by going down the 716 * linked list in "uobj->memq", or we can go over the address range 717 * by page doing hash table lookups for each address. depending 718 * on how many pages are in the object it may be cheaper to do one 719 * or the other. we set "by_list" to true if we are using memq. 720 * if the cost of a hash lookup was equal to the cost of the list 721 * traversal we could compare the number of pages in the start->stop 722 * range to the total number of pages in the object. however, it 723 * seems that a hash table lookup is more expensive than the linked 724 * list traversal, so we multiply the number of pages in the 725 * start->stop range by a penalty which we define below. 726 */ 727 728 static int 729 uao_put(struct uvm_object *uobj, voff_t start, voff_t stop, int flags) 730 { 731 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 732 struct vm_page *pg, *nextpg, curmp, endmp; 733 bool by_list; 734 voff_t curoff; 735 UVMHIST_FUNC("uao_put"); UVMHIST_CALLED(maphist); 736 737 KASSERT(mutex_owned(&uobj->vmobjlock)); 738 739 curoff = 0; 740 if (flags & PGO_ALLPAGES) { 741 start = 0; 742 stop = aobj->u_pages << PAGE_SHIFT; 743 by_list = true; /* always go by the list */ 744 } else { 745 start = trunc_page(start); 746 if (stop == 0) { 747 stop = aobj->u_pages << PAGE_SHIFT; 748 } else { 749 stop = round_page(stop); 750 } 751 if (stop > (aobj->u_pages << PAGE_SHIFT)) { 752 printf("uao_flush: strange, got an out of range " 753 "flush (fixed)\n"); 754 stop = aobj->u_pages << PAGE_SHIFT; 755 } 756 by_list = (uobj->uo_npages <= 757 ((stop - start) >> PAGE_SHIFT) * UVM_PAGE_TREE_PENALTY); 758 } 759 UVMHIST_LOG(maphist, 760 " flush start=0x%lx, stop=0x%x, by_list=%d, flags=0x%x", 761 start, stop, by_list, flags); 762 763 /* 764 * Don't need to do any work here if we're not freeing 765 * or deactivating pages. 766 */ 767 768 if ((flags & (PGO_DEACTIVATE|PGO_FREE)) == 0) { 769 mutex_exit(&uobj->vmobjlock); 770 return 0; 771 } 772 773 /* 774 * Initialize the marker pages. See the comment in 775 * genfs_putpages() also. 776 */ 777 778 curmp.flags = PG_MARKER; 779 endmp.flags = PG_MARKER; 780 781 /* 782 * now do it. note: we must update nextpg in the body of loop or we 783 * will get stuck. we need to use nextpg if we'll traverse the list 784 * because we may free "pg" before doing the next loop. 785 */ 786 787 if (by_list) { 788 TAILQ_INSERT_TAIL(&uobj->memq, &endmp, listq.queue); 789 nextpg = TAILQ_FIRST(&uobj->memq); 790 } else { 791 curoff = start; 792 nextpg = NULL; /* Quell compiler warning */ 793 } 794 795 /* locked: uobj */ 796 for (;;) { 797 if (by_list) { 798 pg = nextpg; 799 if (pg == &endmp) 800 break; 801 nextpg = TAILQ_NEXT(pg, listq.queue); 802 if (pg->flags & PG_MARKER) 803 continue; 804 if (pg->offset < start || pg->offset >= stop) 805 continue; 806 } else { 807 if (curoff < stop) { 808 pg = uvm_pagelookup(uobj, curoff); 809 curoff += PAGE_SIZE; 810 } else 811 break; 812 if (pg == NULL) 813 continue; 814 } 815 816 /* 817 * wait and try again if the page is busy. 818 */ 819 820 if (pg->flags & PG_BUSY) { 821 if (by_list) { 822 TAILQ_INSERT_BEFORE(pg, &curmp, listq.queue); 823 } 824 pg->flags |= PG_WANTED; 825 UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, 0, 826 "uao_put", 0); 827 mutex_enter(&uobj->vmobjlock); 828 if (by_list) { 829 nextpg = TAILQ_NEXT(&curmp, listq.queue); 830 TAILQ_REMOVE(&uobj->memq, &curmp, 831 listq.queue); 832 } else 833 curoff -= PAGE_SIZE; 834 continue; 835 } 836 837 switch (flags & (PGO_CLEANIT|PGO_FREE|PGO_DEACTIVATE)) { 838 839 /* 840 * XXX In these first 3 cases, we always just 841 * XXX deactivate the page. We may want to 842 * XXX handle the different cases more specifically 843 * XXX in the future. 844 */ 845 846 case PGO_CLEANIT|PGO_FREE: 847 case PGO_CLEANIT|PGO_DEACTIVATE: 848 case PGO_DEACTIVATE: 849 deactivate_it: 850 mutex_enter(&uvm_pageqlock); 851 /* skip the page if it's wired */ 852 if (pg->wire_count == 0) { 853 uvm_pagedeactivate(pg); 854 } 855 mutex_exit(&uvm_pageqlock); 856 break; 857 858 case PGO_FREE: 859 /* 860 * If there are multiple references to 861 * the object, just deactivate the page. 862 */ 863 864 if (uobj->uo_refs > 1) 865 goto deactivate_it; 866 867 /* 868 * free the swap slot and the page. 869 */ 870 871 pmap_page_protect(pg, VM_PROT_NONE); 872 873 /* 874 * freeing swapslot here is not strictly necessary. 875 * however, leaving it here doesn't save much 876 * because we need to update swap accounting anyway. 877 */ 878 879 uao_dropswap(uobj, pg->offset >> PAGE_SHIFT); 880 mutex_enter(&uvm_pageqlock); 881 uvm_pagefree(pg); 882 mutex_exit(&uvm_pageqlock); 883 break; 884 885 default: 886 panic("%s: impossible", __func__); 887 } 888 } 889 if (by_list) { 890 TAILQ_REMOVE(&uobj->memq, &endmp, listq.queue); 891 } 892 mutex_exit(&uobj->vmobjlock); 893 return 0; 894 } 895 896 /* 897 * uao_get: fetch me a page 898 * 899 * we have three cases: 900 * 1: page is resident -> just return the page. 901 * 2: page is zero-fill -> allocate a new page and zero it. 902 * 3: page is swapped out -> fetch the page from swap. 903 * 904 * cases 1 and 2 can be handled with PGO_LOCKED, case 3 cannot. 905 * so, if the "center" page hits case 3 (or any page, with PGO_ALLPAGES), 906 * then we will need to return EBUSY. 907 * 908 * => prefer map unlocked (not required) 909 * => object must be locked! we will _unlock_ it before starting any I/O. 910 * => flags: PGO_ALLPAGES: get all of the pages 911 * PGO_LOCKED: fault data structures are locked 912 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 913 * => NOTE: caller must check for released pages!! 914 */ 915 916 static int 917 uao_get(struct uvm_object *uobj, voff_t offset, struct vm_page **pps, 918 int *npagesp, int centeridx, vm_prot_t access_type, int advice, int flags) 919 { 920 #if defined(VMSWAP) 921 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 922 #endif /* defined(VMSWAP) */ 923 voff_t current_offset; 924 struct vm_page *ptmp = NULL; /* Quell compiler warning */ 925 int lcv, gotpages, maxpages, swslot, pageidx; 926 bool done; 927 UVMHIST_FUNC("uao_get"); UVMHIST_CALLED(pdhist); 928 929 UVMHIST_LOG(pdhist, "aobj=%p offset=%d, flags=%d", 930 (struct uvm_aobj *)uobj, offset, flags,0); 931 932 /* 933 * get number of pages 934 */ 935 936 maxpages = *npagesp; 937 938 /* 939 * step 1: handled the case where fault data structures are locked. 940 */ 941 942 if (flags & PGO_LOCKED) { 943 944 /* 945 * step 1a: get pages that are already resident. only do 946 * this if the data structures are locked (i.e. the first 947 * time through). 948 */ 949 950 done = true; /* be optimistic */ 951 gotpages = 0; /* # of pages we got so far */ 952 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 953 lcv++, current_offset += PAGE_SIZE) { 954 /* do we care about this page? if not, skip it */ 955 if (pps[lcv] == PGO_DONTCARE) 956 continue; 957 ptmp = uvm_pagelookup(uobj, current_offset); 958 959 /* 960 * if page is new, attempt to allocate the page, 961 * zero-fill'd. 962 */ 963 964 if (ptmp == NULL && uao_find_swslot(&aobj->u_obj, 965 current_offset >> PAGE_SHIFT) == 0) { 966 ptmp = uvm_pagealloc(uobj, current_offset, 967 NULL, UVM_PGA_ZERO); 968 if (ptmp) { 969 /* new page */ 970 ptmp->flags &= ~(PG_FAKE); 971 ptmp->pqflags |= PQ_AOBJ; 972 goto gotpage; 973 } 974 } 975 976 /* 977 * to be useful must get a non-busy page 978 */ 979 980 if (ptmp == NULL || (ptmp->flags & PG_BUSY) != 0) { 981 if (lcv == centeridx || 982 (flags & PGO_ALLPAGES) != 0) 983 /* need to do a wait or I/O! */ 984 done = false; 985 continue; 986 } 987 988 /* 989 * useful page: busy/lock it and plug it in our 990 * result array 991 */ 992 993 /* caller must un-busy this page */ 994 ptmp->flags |= PG_BUSY; 995 UVM_PAGE_OWN(ptmp, "uao_get1"); 996 gotpage: 997 pps[lcv] = ptmp; 998 gotpages++; 999 } 1000 1001 /* 1002 * step 1b: now we've either done everything needed or we 1003 * to unlock and do some waiting or I/O. 1004 */ 1005 1006 UVMHIST_LOG(pdhist, "<- done (done=%d)", done, 0,0,0); 1007 *npagesp = gotpages; 1008 if (done) 1009 return 0; 1010 else 1011 return EBUSY; 1012 } 1013 1014 /* 1015 * step 2: get non-resident or busy pages. 1016 * object is locked. data structures are unlocked. 1017 */ 1018 1019 if ((flags & PGO_SYNCIO) == 0) { 1020 goto done; 1021 } 1022 1023 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 1024 lcv++, current_offset += PAGE_SIZE) { 1025 1026 /* 1027 * - skip over pages we've already gotten or don't want 1028 * - skip over pages we don't _have_ to get 1029 */ 1030 1031 if (pps[lcv] != NULL || 1032 (lcv != centeridx && (flags & PGO_ALLPAGES) == 0)) 1033 continue; 1034 1035 pageidx = current_offset >> PAGE_SHIFT; 1036 1037 /* 1038 * we have yet to locate the current page (pps[lcv]). we 1039 * first look for a page that is already at the current offset. 1040 * if we find a page, we check to see if it is busy or 1041 * released. if that is the case, then we sleep on the page 1042 * until it is no longer busy or released and repeat the lookup. 1043 * if the page we found is neither busy nor released, then we 1044 * busy it (so we own it) and plug it into pps[lcv]. this 1045 * 'break's the following while loop and indicates we are 1046 * ready to move on to the next page in the "lcv" loop above. 1047 * 1048 * if we exit the while loop with pps[lcv] still set to NULL, 1049 * then it means that we allocated a new busy/fake/clean page 1050 * ptmp in the object and we need to do I/O to fill in the data. 1051 */ 1052 1053 /* top of "pps" while loop */ 1054 while (pps[lcv] == NULL) { 1055 /* look for a resident page */ 1056 ptmp = uvm_pagelookup(uobj, current_offset); 1057 1058 /* not resident? allocate one now (if we can) */ 1059 if (ptmp == NULL) { 1060 1061 ptmp = uvm_pagealloc(uobj, current_offset, 1062 NULL, 0); 1063 1064 /* out of RAM? */ 1065 if (ptmp == NULL) { 1066 mutex_exit(&uobj->vmobjlock); 1067 UVMHIST_LOG(pdhist, 1068 "sleeping, ptmp == NULL\n",0,0,0,0); 1069 uvm_wait("uao_getpage"); 1070 mutex_enter(&uobj->vmobjlock); 1071 continue; 1072 } 1073 1074 /* 1075 * safe with PQ's unlocked: because we just 1076 * alloc'd the page 1077 */ 1078 1079 ptmp->pqflags |= PQ_AOBJ; 1080 1081 /* 1082 * got new page ready for I/O. break pps while 1083 * loop. pps[lcv] is still NULL. 1084 */ 1085 1086 break; 1087 } 1088 1089 /* page is there, see if we need to wait on it */ 1090 if ((ptmp->flags & PG_BUSY) != 0) { 1091 ptmp->flags |= PG_WANTED; 1092 UVMHIST_LOG(pdhist, 1093 "sleeping, ptmp->flags 0x%x\n", 1094 ptmp->flags,0,0,0); 1095 UVM_UNLOCK_AND_WAIT(ptmp, &uobj->vmobjlock, 1096 false, "uao_get", 0); 1097 mutex_enter(&uobj->vmobjlock); 1098 continue; 1099 } 1100 1101 /* 1102 * if we get here then the page has become resident and 1103 * unbusy between steps 1 and 2. we busy it now (so we 1104 * own it) and set pps[lcv] (so that we exit the while 1105 * loop). 1106 */ 1107 1108 /* we own it, caller must un-busy */ 1109 ptmp->flags |= PG_BUSY; 1110 UVM_PAGE_OWN(ptmp, "uao_get2"); 1111 pps[lcv] = ptmp; 1112 } 1113 1114 /* 1115 * if we own the valid page at the correct offset, pps[lcv] will 1116 * point to it. nothing more to do except go to the next page. 1117 */ 1118 1119 if (pps[lcv]) 1120 continue; /* next lcv */ 1121 1122 /* 1123 * we have a "fake/busy/clean" page that we just allocated. 1124 * do the needed "i/o", either reading from swap or zeroing. 1125 */ 1126 1127 swslot = uao_find_swslot(&aobj->u_obj, pageidx); 1128 1129 /* 1130 * just zero the page if there's nothing in swap. 1131 */ 1132 1133 if (swslot == 0) { 1134 1135 /* 1136 * page hasn't existed before, just zero it. 1137 */ 1138 1139 uvm_pagezero(ptmp); 1140 } else { 1141 #if defined(VMSWAP) 1142 int error; 1143 1144 UVMHIST_LOG(pdhist, "pagein from swslot %d", 1145 swslot, 0,0,0); 1146 1147 /* 1148 * page in the swapped-out page. 1149 * unlock object for i/o, relock when done. 1150 */ 1151 1152 mutex_exit(&uobj->vmobjlock); 1153 error = uvm_swap_get(ptmp, swslot, PGO_SYNCIO); 1154 mutex_enter(&uobj->vmobjlock); 1155 1156 /* 1157 * I/O done. check for errors. 1158 */ 1159 1160 if (error != 0) { 1161 UVMHIST_LOG(pdhist, "<- done (error=%d)", 1162 error,0,0,0); 1163 if (ptmp->flags & PG_WANTED) 1164 wakeup(ptmp); 1165 1166 /* 1167 * remove the swap slot from the aobj 1168 * and mark the aobj as having no real slot. 1169 * don't free the swap slot, thus preventing 1170 * it from being used again. 1171 */ 1172 1173 swslot = uao_set_swslot(&aobj->u_obj, pageidx, 1174 SWSLOT_BAD); 1175 if (swslot > 0) { 1176 uvm_swap_markbad(swslot, 1); 1177 } 1178 1179 mutex_enter(&uvm_pageqlock); 1180 uvm_pagefree(ptmp); 1181 mutex_exit(&uvm_pageqlock); 1182 mutex_exit(&uobj->vmobjlock); 1183 return error; 1184 } 1185 #else /* defined(VMSWAP) */ 1186 panic("%s: pagein", __func__); 1187 #endif /* defined(VMSWAP) */ 1188 } 1189 1190 if ((access_type & VM_PROT_WRITE) == 0) { 1191 ptmp->flags |= PG_CLEAN; 1192 pmap_clear_modify(ptmp); 1193 } 1194 1195 /* 1196 * we got the page! clear the fake flag (indicates valid 1197 * data now in page) and plug into our result array. note 1198 * that page is still busy. 1199 * 1200 * it is the callers job to: 1201 * => check if the page is released 1202 * => unbusy the page 1203 * => activate the page 1204 */ 1205 1206 ptmp->flags &= ~PG_FAKE; 1207 pps[lcv] = ptmp; 1208 } 1209 1210 /* 1211 * finally, unlock object and return. 1212 */ 1213 1214 done: 1215 mutex_exit(&uobj->vmobjlock); 1216 UVMHIST_LOG(pdhist, "<- done (OK)",0,0,0,0); 1217 return 0; 1218 } 1219 1220 #if defined(VMSWAP) 1221 1222 /* 1223 * uao_dropswap: release any swap resources from this aobj page. 1224 * 1225 * => aobj must be locked or have a reference count of 0. 1226 */ 1227 1228 void 1229 uao_dropswap(struct uvm_object *uobj, int pageidx) 1230 { 1231 int slot; 1232 1233 slot = uao_set_swslot(uobj, pageidx, 0); 1234 if (slot) { 1235 uvm_swap_free(slot, 1); 1236 } 1237 } 1238 1239 /* 1240 * page in every page in every aobj that is paged-out to a range of swslots. 1241 * 1242 * => nothing should be locked. 1243 * => returns true if pagein was aborted due to lack of memory. 1244 */ 1245 1246 bool 1247 uao_swap_off(int startslot, int endslot) 1248 { 1249 struct uvm_aobj *aobj, *nextaobj; 1250 bool rv; 1251 1252 /* 1253 * walk the list of all aobjs. 1254 */ 1255 1256 restart: 1257 mutex_enter(&uao_list_lock); 1258 for (aobj = LIST_FIRST(&uao_list); 1259 aobj != NULL; 1260 aobj = nextaobj) { 1261 1262 /* 1263 * try to get the object lock, start all over if we fail. 1264 * most of the time we'll get the aobj lock, 1265 * so this should be a rare case. 1266 */ 1267 1268 if (!mutex_tryenter(&aobj->u_obj.vmobjlock)) { 1269 mutex_exit(&uao_list_lock); 1270 /* XXX Better than yielding but inadequate. */ 1271 kpause("livelock", false, 1, NULL); 1272 goto restart; 1273 } 1274 1275 /* 1276 * add a ref to the aobj so it doesn't disappear 1277 * while we're working. 1278 */ 1279 1280 uao_reference_locked(&aobj->u_obj); 1281 1282 /* 1283 * now it's safe to unlock the uao list. 1284 */ 1285 1286 mutex_exit(&uao_list_lock); 1287 1288 /* 1289 * page in any pages in the swslot range. 1290 * if there's an error, abort and return the error. 1291 */ 1292 1293 rv = uao_pagein(aobj, startslot, endslot); 1294 if (rv) { 1295 uao_detach_locked(&aobj->u_obj); 1296 return rv; 1297 } 1298 1299 /* 1300 * we're done with this aobj. 1301 * relock the list and drop our ref on the aobj. 1302 */ 1303 1304 mutex_enter(&uao_list_lock); 1305 nextaobj = LIST_NEXT(aobj, u_list); 1306 uao_detach_locked(&aobj->u_obj); 1307 } 1308 1309 /* 1310 * done with traversal, unlock the list 1311 */ 1312 mutex_exit(&uao_list_lock); 1313 return false; 1314 } 1315 1316 1317 /* 1318 * page in any pages from aobj in the given range. 1319 * 1320 * => aobj must be locked and is returned locked. 1321 * => returns true if pagein was aborted due to lack of memory. 1322 */ 1323 static bool 1324 uao_pagein(struct uvm_aobj *aobj, int startslot, int endslot) 1325 { 1326 bool rv; 1327 1328 if (UAO_USES_SWHASH(aobj)) { 1329 struct uao_swhash_elt *elt; 1330 int buck; 1331 1332 restart: 1333 for (buck = aobj->u_swhashmask; buck >= 0; buck--) { 1334 for (elt = LIST_FIRST(&aobj->u_swhash[buck]); 1335 elt != NULL; 1336 elt = LIST_NEXT(elt, list)) { 1337 int i; 1338 1339 for (i = 0; i < UAO_SWHASH_CLUSTER_SIZE; i++) { 1340 int slot = elt->slots[i]; 1341 1342 /* 1343 * if the slot isn't in range, skip it. 1344 */ 1345 1346 if (slot < startslot || 1347 slot >= endslot) { 1348 continue; 1349 } 1350 1351 /* 1352 * process the page, 1353 * the start over on this object 1354 * since the swhash elt 1355 * may have been freed. 1356 */ 1357 1358 rv = uao_pagein_page(aobj, 1359 UAO_SWHASH_ELT_PAGEIDX_BASE(elt) + i); 1360 if (rv) { 1361 return rv; 1362 } 1363 goto restart; 1364 } 1365 } 1366 } 1367 } else { 1368 int i; 1369 1370 for (i = 0; i < aobj->u_pages; i++) { 1371 int slot = aobj->u_swslots[i]; 1372 1373 /* 1374 * if the slot isn't in range, skip it 1375 */ 1376 1377 if (slot < startslot || slot >= endslot) { 1378 continue; 1379 } 1380 1381 /* 1382 * process the page. 1383 */ 1384 1385 rv = uao_pagein_page(aobj, i); 1386 if (rv) { 1387 return rv; 1388 } 1389 } 1390 } 1391 1392 return false; 1393 } 1394 1395 /* 1396 * page in a page from an aobj. used for swap_off. 1397 * returns true if pagein was aborted due to lack of memory. 1398 * 1399 * => aobj must be locked and is returned locked. 1400 */ 1401 1402 static bool 1403 uao_pagein_page(struct uvm_aobj *aobj, int pageidx) 1404 { 1405 struct vm_page *pg; 1406 int rv, npages; 1407 1408 pg = NULL; 1409 npages = 1; 1410 /* locked: aobj */ 1411 rv = uao_get(&aobj->u_obj, pageidx << PAGE_SHIFT, 1412 &pg, &npages, 0, VM_PROT_READ|VM_PROT_WRITE, 0, PGO_SYNCIO); 1413 /* unlocked: aobj */ 1414 1415 /* 1416 * relock and finish up. 1417 */ 1418 1419 mutex_enter(&aobj->u_obj.vmobjlock); 1420 switch (rv) { 1421 case 0: 1422 break; 1423 1424 case EIO: 1425 case ERESTART: 1426 1427 /* 1428 * nothing more to do on errors. 1429 * ERESTART can only mean that the anon was freed, 1430 * so again there's nothing to do. 1431 */ 1432 1433 return false; 1434 1435 default: 1436 return true; 1437 } 1438 1439 /* 1440 * ok, we've got the page now. 1441 * mark it as dirty, clear its swslot and un-busy it. 1442 */ 1443 uao_dropswap(&aobj->u_obj, pageidx); 1444 1445 /* 1446 * make sure it's on a page queue. 1447 */ 1448 mutex_enter(&uvm_pageqlock); 1449 if (pg->wire_count == 0) 1450 uvm_pageenqueue(pg); 1451 mutex_exit(&uvm_pageqlock); 1452 1453 if (pg->flags & PG_WANTED) { 1454 wakeup(pg); 1455 } 1456 pg->flags &= ~(PG_WANTED|PG_BUSY|PG_CLEAN|PG_FAKE); 1457 UVM_PAGE_OWN(pg, NULL); 1458 1459 return false; 1460 } 1461 1462 /* 1463 * uao_dropswap_range: drop swapslots in the range. 1464 * 1465 * => aobj must be locked and is returned locked. 1466 * => start is inclusive. end is exclusive. 1467 */ 1468 1469 void 1470 uao_dropswap_range(struct uvm_object *uobj, voff_t start, voff_t end) 1471 { 1472 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 1473 1474 KASSERT(mutex_owned(&uobj->vmobjlock)); 1475 1476 uao_dropswap_range1(aobj, start, end); 1477 } 1478 1479 static void 1480 uao_dropswap_range1(struct uvm_aobj *aobj, voff_t start, voff_t end) 1481 { 1482 int swpgonlydelta = 0; 1483 1484 if (end == 0) { 1485 end = INT64_MAX; 1486 } 1487 1488 if (UAO_USES_SWHASH(aobj)) { 1489 int i, hashbuckets = aobj->u_swhashmask + 1; 1490 voff_t taghi; 1491 voff_t taglo; 1492 1493 taglo = UAO_SWHASH_ELT_TAG(start); 1494 taghi = UAO_SWHASH_ELT_TAG(end); 1495 1496 for (i = 0; i < hashbuckets; i++) { 1497 struct uao_swhash_elt *elt, *next; 1498 1499 for (elt = LIST_FIRST(&aobj->u_swhash[i]); 1500 elt != NULL; 1501 elt = next) { 1502 int startidx, endidx; 1503 int j; 1504 1505 next = LIST_NEXT(elt, list); 1506 1507 if (elt->tag < taglo || taghi < elt->tag) { 1508 continue; 1509 } 1510 1511 if (elt->tag == taglo) { 1512 startidx = 1513 UAO_SWHASH_ELT_PAGESLOT_IDX(start); 1514 } else { 1515 startidx = 0; 1516 } 1517 1518 if (elt->tag == taghi) { 1519 endidx = 1520 UAO_SWHASH_ELT_PAGESLOT_IDX(end); 1521 } else { 1522 endidx = UAO_SWHASH_CLUSTER_SIZE; 1523 } 1524 1525 for (j = startidx; j < endidx; j++) { 1526 int slot = elt->slots[j]; 1527 1528 KASSERT(uvm_pagelookup(&aobj->u_obj, 1529 (UAO_SWHASH_ELT_PAGEIDX_BASE(elt) 1530 + j) << PAGE_SHIFT) == NULL); 1531 if (slot > 0) { 1532 uvm_swap_free(slot, 1); 1533 swpgonlydelta++; 1534 KASSERT(elt->count > 0); 1535 elt->slots[j] = 0; 1536 elt->count--; 1537 } 1538 } 1539 1540 if (elt->count == 0) { 1541 LIST_REMOVE(elt, list); 1542 pool_put(&uao_swhash_elt_pool, elt); 1543 } 1544 } 1545 } 1546 } else { 1547 int i; 1548 1549 if (aobj->u_pages < end) { 1550 end = aobj->u_pages; 1551 } 1552 for (i = start; i < end; i++) { 1553 int slot = aobj->u_swslots[i]; 1554 1555 if (slot > 0) { 1556 uvm_swap_free(slot, 1); 1557 swpgonlydelta++; 1558 } 1559 } 1560 } 1561 1562 /* 1563 * adjust the counter of pages only in swap for all 1564 * the swap slots we've freed. 1565 */ 1566 1567 if (swpgonlydelta > 0) { 1568 mutex_enter(&uvm_swap_data_lock); 1569 KASSERT(uvmexp.swpgonly >= swpgonlydelta); 1570 uvmexp.swpgonly -= swpgonlydelta; 1571 mutex_exit(&uvm_swap_data_lock); 1572 } 1573 } 1574 1575 #endif /* defined(VMSWAP) */ 1576