1 /* $NetBSD: uvm_aobj.c,v 1.81 2006/10/12 01:32:52 christos 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 1.81 2006/10/12 01:32:52 christos 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 simple_unlock(&aobj->u_obj.vmobjlock); 405 406 #if defined(VMSWAP) 407 uao_dropswap_range1(aobj, 0, 0); 408 409 if (UAO_USES_SWHASH(aobj)) { 410 411 /* 412 * free the hash table itself. 413 */ 414 415 free(aobj->u_swhash, M_UVMAOBJ); 416 } else { 417 418 /* 419 * free the array itsself. 420 */ 421 422 free(aobj->u_swslots, M_UVMAOBJ); 423 } 424 #endif /* defined(VMSWAP) */ 425 426 /* 427 * finally free the aobj itself 428 */ 429 430 pool_put(&uvm_aobj_pool, aobj); 431 432 /* 433 * adjust the counter of pages only in swap for all 434 * the swap slots we've freed. 435 */ 436 437 if (swpgonlydelta > 0) { 438 simple_lock(&uvm.swap_data_lock); 439 KASSERT(uvmexp.swpgonly >= swpgonlydelta); 440 uvmexp.swpgonly -= swpgonlydelta; 441 simple_unlock(&uvm.swap_data_lock); 442 } 443 } 444 445 /* 446 * pager functions 447 */ 448 449 /* 450 * uao_create: create an aobj of the given size and return its uvm_object. 451 * 452 * => for normal use, flags are always zero 453 * => for the kernel object, the flags are: 454 * UAO_FLAG_KERNOBJ - allocate the kernel object (can only happen once) 455 * UAO_FLAG_KERNSWAP - enable swapping of kernel object (" ") 456 */ 457 458 struct uvm_object * 459 uao_create(vsize_t size, int flags) 460 { 461 static struct uvm_aobj kernel_object_store; 462 static int kobj_alloced = 0; 463 pgoff_t pages = round_page(size) >> PAGE_SHIFT; 464 struct uvm_aobj *aobj; 465 int refs; 466 467 /* 468 * malloc a new aobj unless we are asked for the kernel object 469 */ 470 471 if (flags & UAO_FLAG_KERNOBJ) { 472 KASSERT(!kobj_alloced); 473 aobj = &kernel_object_store; 474 aobj->u_pages = pages; 475 aobj->u_flags = UAO_FLAG_NOSWAP; 476 refs = UVM_OBJ_KERN; 477 kobj_alloced = UAO_FLAG_KERNOBJ; 478 } else if (flags & UAO_FLAG_KERNSWAP) { 479 KASSERT(kobj_alloced == UAO_FLAG_KERNOBJ); 480 aobj = &kernel_object_store; 481 kobj_alloced = UAO_FLAG_KERNSWAP; 482 refs = 0xdeadbeaf; /* XXX: gcc */ 483 } else { 484 aobj = pool_get(&uvm_aobj_pool, PR_WAITOK); 485 aobj->u_pages = pages; 486 aobj->u_flags = 0; 487 refs = 1; 488 } 489 490 /* 491 * allocate hash/array if necessary 492 * 493 * note: in the KERNSWAP case no need to worry about locking since 494 * we are still booting we should be the only thread around. 495 */ 496 497 if (flags == 0 || (flags & UAO_FLAG_KERNSWAP) != 0) { 498 #if defined(VMSWAP) 499 int mflags = (flags & UAO_FLAG_KERNSWAP) != 0 ? 500 M_NOWAIT : M_WAITOK; 501 502 /* allocate hash table or array depending on object size */ 503 if (UAO_USES_SWHASH(aobj)) { 504 aobj->u_swhash = hashinit(UAO_SWHASH_BUCKETS(aobj), 505 HASH_LIST, M_UVMAOBJ, mflags, &aobj->u_swhashmask); 506 if (aobj->u_swhash == NULL) 507 panic("uao_create: hashinit swhash failed"); 508 } else { 509 aobj->u_swslots = malloc(pages * sizeof(int), 510 M_UVMAOBJ, mflags); 511 if (aobj->u_swslots == NULL) 512 panic("uao_create: malloc swslots failed"); 513 memset(aobj->u_swslots, 0, pages * sizeof(int)); 514 } 515 #endif /* defined(VMSWAP) */ 516 517 if (flags) { 518 aobj->u_flags &= ~UAO_FLAG_NOSWAP; /* clear noswap */ 519 return(&aobj->u_obj); 520 } 521 } 522 523 /* 524 * init aobj fields 525 */ 526 527 UVM_OBJ_INIT(&aobj->u_obj, &aobj_pager, refs); 528 529 /* 530 * now that aobj is ready, add it to the global list 531 */ 532 533 simple_lock(&uao_list_lock); 534 LIST_INSERT_HEAD(&uao_list, aobj, u_list); 535 simple_unlock(&uao_list_lock); 536 return(&aobj->u_obj); 537 } 538 539 540 541 /* 542 * uao_init: set up aobj pager subsystem 543 * 544 * => called at boot time from uvm_pager_init() 545 */ 546 547 void 548 uao_init(void) 549 { 550 static int uao_initialized; 551 552 if (uao_initialized) 553 return; 554 uao_initialized = TRUE; 555 LIST_INIT(&uao_list); 556 simple_lock_init(&uao_list_lock); 557 } 558 559 /* 560 * uao_reference: add a ref to an aobj 561 * 562 * => aobj must be unlocked 563 * => just lock it and call the locked version 564 */ 565 566 void 567 uao_reference(struct uvm_object *uobj) 568 { 569 simple_lock(&uobj->vmobjlock); 570 uao_reference_locked(uobj); 571 simple_unlock(&uobj->vmobjlock); 572 } 573 574 /* 575 * uao_reference_locked: add a ref to an aobj that is already locked 576 * 577 * => aobj must be locked 578 * this needs to be separate from the normal routine 579 * since sometimes we need to add a reference to an aobj when 580 * it's already locked. 581 */ 582 583 void 584 uao_reference_locked(struct uvm_object *uobj) 585 { 586 UVMHIST_FUNC("uao_reference"); UVMHIST_CALLED(maphist); 587 588 /* 589 * kernel_object already has plenty of references, leave it alone. 590 */ 591 592 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) 593 return; 594 595 uobj->uo_refs++; 596 UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)", 597 uobj, uobj->uo_refs,0,0); 598 } 599 600 /* 601 * uao_detach: drop a reference to an aobj 602 * 603 * => aobj must be unlocked 604 * => just lock it and call the locked version 605 */ 606 607 void 608 uao_detach(struct uvm_object *uobj) 609 { 610 simple_lock(&uobj->vmobjlock); 611 uao_detach_locked(uobj); 612 } 613 614 /* 615 * uao_detach_locked: drop a reference to an aobj 616 * 617 * => aobj must be locked, and is unlocked (or freed) upon return. 618 * this needs to be separate from the normal routine 619 * since sometimes we need to detach from an aobj when 620 * it's already locked. 621 */ 622 623 void 624 uao_detach_locked(struct uvm_object *uobj) 625 { 626 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 627 struct vm_page *pg; 628 UVMHIST_FUNC("uao_detach"); UVMHIST_CALLED(maphist); 629 630 /* 631 * detaching from kernel_object is a noop. 632 */ 633 634 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) { 635 simple_unlock(&uobj->vmobjlock); 636 return; 637 } 638 639 UVMHIST_LOG(maphist," (uobj=0x%x) ref=%d", uobj,uobj->uo_refs,0,0); 640 uobj->uo_refs--; 641 if (uobj->uo_refs) { 642 simple_unlock(&uobj->vmobjlock); 643 UVMHIST_LOG(maphist, "<- done (rc>0)", 0,0,0,0); 644 return; 645 } 646 647 /* 648 * remove the aobj from the global list. 649 */ 650 651 simple_lock(&uao_list_lock); 652 LIST_REMOVE(aobj, u_list); 653 simple_unlock(&uao_list_lock); 654 655 /* 656 * free all the pages left in the aobj. for each page, 657 * when the page is no longer busy (and thus after any disk i/o that 658 * it's involved in is complete), release any swap resources and 659 * free the page itself. 660 */ 661 662 uvm_lock_pageq(); 663 while ((pg = TAILQ_FIRST(&uobj->memq)) != NULL) { 664 pmap_page_protect(pg, VM_PROT_NONE); 665 if (pg->flags & PG_BUSY) { 666 pg->flags |= PG_WANTED; 667 uvm_unlock_pageq(); 668 UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, FALSE, 669 "uao_det", 0); 670 simple_lock(&uobj->vmobjlock); 671 uvm_lock_pageq(); 672 continue; 673 } 674 uao_dropswap(&aobj->u_obj, pg->offset >> PAGE_SHIFT); 675 uvm_pagefree(pg); 676 } 677 uvm_unlock_pageq(); 678 679 /* 680 * finally, free the aobj itself. 681 */ 682 683 uao_free(aobj); 684 } 685 686 /* 687 * uao_put: flush pages out of a uvm object 688 * 689 * => object should be locked by caller. we may _unlock_ the object 690 * if (and only if) we need to clean a page (PGO_CLEANIT). 691 * XXXJRT Currently, however, we don't. In the case of cleaning 692 * XXXJRT a page, we simply just deactivate it. Should probably 693 * XXXJRT handle this better, in the future (although "flushing" 694 * XXXJRT anonymous memory isn't terribly important). 695 * => if PGO_CLEANIT is not set, then we will neither unlock the object 696 * or block. 697 * => if PGO_ALLPAGE is set, then all pages in the object are valid targets 698 * for flushing. 699 * => NOTE: we rely on the fact that the object's memq is a TAILQ and 700 * that new pages are inserted on the tail end of the list. thus, 701 * we can make a complete pass through the object in one go by starting 702 * at the head and working towards the tail (new pages are put in 703 * front of us). 704 * => NOTE: we are allowed to lock the page queues, so the caller 705 * must not be holding the lock on them [e.g. pagedaemon had 706 * better not call us with the queues locked] 707 * => we return TRUE unless we encountered some sort of I/O error 708 * XXXJRT currently never happens, as we never directly initiate 709 * XXXJRT I/O 710 * 711 * note on page traversal: 712 * we can traverse the pages in an object either by going down the 713 * linked list in "uobj->memq", or we can go over the address range 714 * by page doing hash table lookups for each address. depending 715 * on how many pages are in the object it may be cheaper to do one 716 * or the other. we set "by_list" to true if we are using memq. 717 * if the cost of a hash lookup was equal to the cost of the list 718 * traversal we could compare the number of pages in the start->stop 719 * range to the total number of pages in the object. however, it 720 * seems that a hash table lookup is more expensive than the linked 721 * list traversal, so we multiply the number of pages in the 722 * start->stop range by a penalty which we define below. 723 */ 724 725 static int 726 uao_put(struct uvm_object *uobj, voff_t start, voff_t stop, int flags) 727 { 728 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 729 struct vm_page *pg, *nextpg, curmp, endmp; 730 boolean_t by_list; 731 voff_t curoff; 732 UVMHIST_FUNC("uao_put"); UVMHIST_CALLED(maphist); 733 734 curoff = 0; 735 if (flags & PGO_ALLPAGES) { 736 start = 0; 737 stop = aobj->u_pages << PAGE_SHIFT; 738 by_list = TRUE; /* always go by the list */ 739 } else { 740 start = trunc_page(start); 741 if (stop == 0) { 742 stop = aobj->u_pages << PAGE_SHIFT; 743 } else { 744 stop = round_page(stop); 745 } 746 if (stop > (aobj->u_pages << PAGE_SHIFT)) { 747 printf("uao_flush: strange, got an out of range " 748 "flush (fixed)\n"); 749 stop = aobj->u_pages << PAGE_SHIFT; 750 } 751 by_list = (uobj->uo_npages <= 752 ((stop - start) >> PAGE_SHIFT) * UVM_PAGE_HASH_PENALTY); 753 } 754 UVMHIST_LOG(maphist, 755 " flush start=0x%lx, stop=0x%x, by_list=%d, flags=0x%x", 756 start, stop, by_list, flags); 757 758 /* 759 * Don't need to do any work here if we're not freeing 760 * or deactivating pages. 761 */ 762 763 if ((flags & (PGO_DEACTIVATE|PGO_FREE)) == 0) { 764 simple_unlock(&uobj->vmobjlock); 765 return 0; 766 } 767 768 /* 769 * Initialize the marker pages. See the comment in 770 * genfs_putpages() also. 771 */ 772 773 curmp.uobject = uobj; 774 curmp.offset = (voff_t)-1; 775 curmp.flags = PG_BUSY; 776 endmp.uobject = uobj; 777 endmp.offset = (voff_t)-1; 778 endmp.flags = PG_BUSY; 779 780 /* 781 * now do it. note: we must update nextpg in the body of loop or we 782 * will get stuck. we need to use nextpg if we'll traverse the list 783 * because we may free "pg" before doing the next loop. 784 */ 785 786 if (by_list) { 787 TAILQ_INSERT_TAIL(&uobj->memq, &endmp, listq); 788 nextpg = TAILQ_FIRST(&uobj->memq); 789 PHOLD(curlwp); 790 } else { 791 curoff = start; 792 nextpg = NULL; /* Quell compiler warning */ 793 } 794 795 uvm_lock_pageq(); 796 797 /* locked: both page queues and uobj */ 798 for (;;) { 799 if (by_list) { 800 pg = nextpg; 801 if (pg == &endmp) 802 break; 803 nextpg = TAILQ_NEXT(pg, listq); 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 switch (flags & (PGO_CLEANIT|PGO_FREE|PGO_DEACTIVATE)) { 816 817 /* 818 * XXX In these first 3 cases, we always just 819 * XXX deactivate the page. We may want to 820 * XXX handle the different cases more specifically 821 * XXX in the future. 822 */ 823 824 case PGO_CLEANIT|PGO_FREE: 825 case PGO_CLEANIT|PGO_DEACTIVATE: 826 case PGO_DEACTIVATE: 827 deactivate_it: 828 /* skip the page if it's loaned or wired */ 829 if (pg->loan_count != 0 || pg->wire_count != 0) 830 continue; 831 832 /* ...and deactivate the page. */ 833 pmap_clear_reference(pg); 834 uvm_pagedeactivate(pg); 835 continue; 836 837 case PGO_FREE: 838 839 /* 840 * If there are multiple references to 841 * the object, just deactivate the page. 842 */ 843 844 if (uobj->uo_refs > 1) 845 goto deactivate_it; 846 847 /* 848 * wait and try again if the page is busy. 849 * otherwise free the swap slot and the page. 850 */ 851 852 pmap_page_protect(pg, VM_PROT_NONE); 853 if (pg->flags & PG_BUSY) { 854 if (by_list) { 855 TAILQ_INSERT_BEFORE(pg, &curmp, listq); 856 } 857 pg->flags |= PG_WANTED; 858 uvm_unlock_pageq(); 859 UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, 0, 860 "uao_put", 0); 861 simple_lock(&uobj->vmobjlock); 862 uvm_lock_pageq(); 863 if (by_list) { 864 nextpg = TAILQ_NEXT(&curmp, listq); 865 TAILQ_REMOVE(&uobj->memq, &curmp, 866 listq); 867 } else 868 curoff -= PAGE_SIZE; 869 continue; 870 } 871 872 /* 873 * freeing swapslot here is not strictly necessary. 874 * however, leaving it here doesn't save much 875 * because we need to update swap accounting anyway. 876 */ 877 878 uao_dropswap(uobj, pg->offset >> PAGE_SHIFT); 879 uvm_pagefree(pg); 880 continue; 881 } 882 } 883 uvm_unlock_pageq(); 884 if (by_list) { 885 TAILQ_REMOVE(&uobj->memq, &endmp, listq); 886 PRELE(curlwp); 887 } 888 simple_unlock(&uobj->vmobjlock); 889 return 0; 890 } 891 892 /* 893 * uao_get: fetch me a page 894 * 895 * we have three cases: 896 * 1: page is resident -> just return the page. 897 * 2: page is zero-fill -> allocate a new page and zero it. 898 * 3: page is swapped out -> fetch the page from swap. 899 * 900 * cases 1 and 2 can be handled with PGO_LOCKED, case 3 cannot. 901 * so, if the "center" page hits case 3 (or any page, with PGO_ALLPAGES), 902 * then we will need to return EBUSY. 903 * 904 * => prefer map unlocked (not required) 905 * => object must be locked! we will _unlock_ it before starting any I/O. 906 * => flags: PGO_ALLPAGES: get all of the pages 907 * PGO_LOCKED: fault data structures are locked 908 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 909 * => NOTE: caller must check for released pages!! 910 */ 911 912 static int 913 uao_get(struct uvm_object *uobj, voff_t offset, struct vm_page **pps, 914 int *npagesp, int centeridx, vm_prot_t access_type, int advice __unused, 915 int flags) 916 { 917 #if defined(VMSWAP) 918 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 919 #endif /* defined(VMSWAP) */ 920 voff_t current_offset; 921 struct vm_page *ptmp = NULL; /* Quell compiler warning */ 922 int lcv, gotpages, maxpages, swslot, pageidx; 923 boolean_t done; 924 UVMHIST_FUNC("uao_get"); UVMHIST_CALLED(pdhist); 925 926 UVMHIST_LOG(pdhist, "aobj=%p offset=%d, flags=%d", 927 (struct uvm_aobj *)uobj, offset, flags,0); 928 929 /* 930 * get number of pages 931 */ 932 933 maxpages = *npagesp; 934 935 /* 936 * step 1: handled the case where fault data structures are locked. 937 */ 938 939 if (flags & PGO_LOCKED) { 940 941 /* 942 * step 1a: get pages that are already resident. only do 943 * this if the data structures are locked (i.e. the first 944 * time through). 945 */ 946 947 done = TRUE; /* be optimistic */ 948 gotpages = 0; /* # of pages we got so far */ 949 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 950 lcv++, current_offset += PAGE_SIZE) { 951 /* do we care about this page? if not, skip it */ 952 if (pps[lcv] == PGO_DONTCARE) 953 continue; 954 ptmp = uvm_pagelookup(uobj, current_offset); 955 956 /* 957 * if page is new, attempt to allocate the page, 958 * zero-fill'd. 959 */ 960 961 if (ptmp == NULL && uao_find_swslot(&aobj->u_obj, 962 current_offset >> PAGE_SHIFT) == 0) { 963 ptmp = uvm_pagealloc(uobj, current_offset, 964 NULL, UVM_PGA_ZERO); 965 if (ptmp) { 966 /* new page */ 967 ptmp->flags &= ~(PG_FAKE); 968 ptmp->pqflags |= PQ_AOBJ; 969 goto gotpage; 970 } 971 } 972 973 /* 974 * to be useful must get a non-busy page 975 */ 976 977 if (ptmp == NULL || (ptmp->flags & PG_BUSY) != 0) { 978 if (lcv == centeridx || 979 (flags & PGO_ALLPAGES) != 0) 980 /* need to do a wait or I/O! */ 981 done = FALSE; 982 continue; 983 } 984 985 /* 986 * useful page: busy/lock it and plug it in our 987 * result array 988 */ 989 990 /* caller must un-busy this page */ 991 ptmp->flags |= PG_BUSY; 992 UVM_PAGE_OWN(ptmp, "uao_get1"); 993 gotpage: 994 pps[lcv] = ptmp; 995 gotpages++; 996 } 997 998 /* 999 * step 1b: now we've either done everything needed or we 1000 * to unlock and do some waiting or I/O. 1001 */ 1002 1003 UVMHIST_LOG(pdhist, "<- done (done=%d)", done, 0,0,0); 1004 *npagesp = gotpages; 1005 if (done) 1006 return 0; 1007 else 1008 return EBUSY; 1009 } 1010 1011 /* 1012 * step 2: get non-resident or busy pages. 1013 * object is locked. data structures are unlocked. 1014 */ 1015 1016 if ((flags & PGO_SYNCIO) == 0) { 1017 goto done; 1018 } 1019 1020 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 1021 lcv++, current_offset += PAGE_SIZE) { 1022 1023 /* 1024 * - skip over pages we've already gotten or don't want 1025 * - skip over pages we don't _have_ to get 1026 */ 1027 1028 if (pps[lcv] != NULL || 1029 (lcv != centeridx && (flags & PGO_ALLPAGES) == 0)) 1030 continue; 1031 1032 pageidx = current_offset >> PAGE_SHIFT; 1033 1034 /* 1035 * we have yet to locate the current page (pps[lcv]). we 1036 * first look for a page that is already at the current offset. 1037 * if we find a page, we check to see if it is busy or 1038 * released. if that is the case, then we sleep on the page 1039 * until it is no longer busy or released and repeat the lookup. 1040 * if the page we found is neither busy nor released, then we 1041 * busy it (so we own it) and plug it into pps[lcv]. this 1042 * 'break's the following while loop and indicates we are 1043 * ready to move on to the next page in the "lcv" loop above. 1044 * 1045 * if we exit the while loop with pps[lcv] still set to NULL, 1046 * then it means that we allocated a new busy/fake/clean page 1047 * ptmp in the object and we need to do I/O to fill in the data. 1048 */ 1049 1050 /* top of "pps" while loop */ 1051 while (pps[lcv] == NULL) { 1052 /* look for a resident page */ 1053 ptmp = uvm_pagelookup(uobj, current_offset); 1054 1055 /* not resident? allocate one now (if we can) */ 1056 if (ptmp == NULL) { 1057 1058 ptmp = uvm_pagealloc(uobj, current_offset, 1059 NULL, 0); 1060 1061 /* out of RAM? */ 1062 if (ptmp == NULL) { 1063 simple_unlock(&uobj->vmobjlock); 1064 UVMHIST_LOG(pdhist, 1065 "sleeping, ptmp == NULL\n",0,0,0,0); 1066 uvm_wait("uao_getpage"); 1067 simple_lock(&uobj->vmobjlock); 1068 continue; 1069 } 1070 1071 /* 1072 * safe with PQ's unlocked: because we just 1073 * alloc'd the page 1074 */ 1075 1076 ptmp->pqflags |= PQ_AOBJ; 1077 1078 /* 1079 * got new page ready for I/O. break pps while 1080 * loop. pps[lcv] is still NULL. 1081 */ 1082 1083 break; 1084 } 1085 1086 /* page is there, see if we need to wait on it */ 1087 if ((ptmp->flags & PG_BUSY) != 0) { 1088 ptmp->flags |= PG_WANTED; 1089 UVMHIST_LOG(pdhist, 1090 "sleeping, ptmp->flags 0x%x\n", 1091 ptmp->flags,0,0,0); 1092 UVM_UNLOCK_AND_WAIT(ptmp, &uobj->vmobjlock, 1093 FALSE, "uao_get", 0); 1094 simple_lock(&uobj->vmobjlock); 1095 continue; 1096 } 1097 1098 /* 1099 * if we get here then the page has become resident and 1100 * unbusy between steps 1 and 2. we busy it now (so we 1101 * own it) and set pps[lcv] (so that we exit the while 1102 * loop). 1103 */ 1104 1105 /* we own it, caller must un-busy */ 1106 ptmp->flags |= PG_BUSY; 1107 UVM_PAGE_OWN(ptmp, "uao_get2"); 1108 pps[lcv] = ptmp; 1109 } 1110 1111 /* 1112 * if we own the valid page at the correct offset, pps[lcv] will 1113 * point to it. nothing more to do except go to the next page. 1114 */ 1115 1116 if (pps[lcv]) 1117 continue; /* next lcv */ 1118 1119 /* 1120 * we have a "fake/busy/clean" page that we just allocated. 1121 * do the needed "i/o", either reading from swap or zeroing. 1122 */ 1123 1124 swslot = uao_find_swslot(&aobj->u_obj, pageidx); 1125 1126 /* 1127 * just zero the page if there's nothing in swap. 1128 */ 1129 1130 if (swslot == 0) { 1131 1132 /* 1133 * page hasn't existed before, just zero it. 1134 */ 1135 1136 uvm_pagezero(ptmp); 1137 } else { 1138 #if defined(VMSWAP) 1139 int error; 1140 1141 UVMHIST_LOG(pdhist, "pagein from swslot %d", 1142 swslot, 0,0,0); 1143 1144 /* 1145 * page in the swapped-out page. 1146 * unlock object for i/o, relock when done. 1147 */ 1148 1149 simple_unlock(&uobj->vmobjlock); 1150 error = uvm_swap_get(ptmp, swslot, PGO_SYNCIO); 1151 simple_lock(&uobj->vmobjlock); 1152 1153 /* 1154 * I/O done. check for errors. 1155 */ 1156 1157 if (error != 0) { 1158 UVMHIST_LOG(pdhist, "<- done (error=%d)", 1159 error,0,0,0); 1160 if (ptmp->flags & PG_WANTED) 1161 wakeup(ptmp); 1162 1163 /* 1164 * remove the swap slot from the aobj 1165 * and mark the aobj as having no real slot. 1166 * don't free the swap slot, thus preventing 1167 * it from being used again. 1168 */ 1169 1170 swslot = uao_set_swslot(&aobj->u_obj, pageidx, 1171 SWSLOT_BAD); 1172 if (swslot > 0) { 1173 uvm_swap_markbad(swslot, 1); 1174 } 1175 1176 uvm_lock_pageq(); 1177 uvm_pagefree(ptmp); 1178 uvm_unlock_pageq(); 1179 simple_unlock(&uobj->vmobjlock); 1180 return error; 1181 } 1182 #else /* defined(VMSWAP) */ 1183 panic("%s: pagein", __func__); 1184 #endif /* defined(VMSWAP) */ 1185 } 1186 1187 if ((access_type & VM_PROT_WRITE) == 0) { 1188 ptmp->flags |= PG_CLEAN; 1189 pmap_clear_modify(ptmp); 1190 } 1191 1192 /* 1193 * we got the page! clear the fake flag (indicates valid 1194 * data now in page) and plug into our result array. note 1195 * that page is still busy. 1196 * 1197 * it is the callers job to: 1198 * => check if the page is released 1199 * => unbusy the page 1200 * => activate the page 1201 */ 1202 1203 ptmp->flags &= ~PG_FAKE; 1204 pps[lcv] = ptmp; 1205 } 1206 1207 /* 1208 * finally, unlock object and return. 1209 */ 1210 1211 done: 1212 simple_unlock(&uobj->vmobjlock); 1213 UVMHIST_LOG(pdhist, "<- done (OK)",0,0,0,0); 1214 return 0; 1215 } 1216 1217 #if defined(VMSWAP) 1218 1219 /* 1220 * uao_dropswap: release any swap resources from this aobj page. 1221 * 1222 * => aobj must be locked or have a reference count of 0. 1223 */ 1224 1225 void 1226 uao_dropswap(struct uvm_object *uobj, int pageidx) 1227 { 1228 int slot; 1229 1230 slot = uao_set_swslot(uobj, pageidx, 0); 1231 if (slot) { 1232 uvm_swap_free(slot, 1); 1233 } 1234 } 1235 1236 /* 1237 * page in every page in every aobj that is paged-out to a range of swslots. 1238 * 1239 * => nothing should be locked. 1240 * => returns TRUE if pagein was aborted due to lack of memory. 1241 */ 1242 1243 boolean_t 1244 uao_swap_off(int startslot, int endslot) 1245 { 1246 struct uvm_aobj *aobj, *nextaobj; 1247 boolean_t rv; 1248 1249 /* 1250 * walk the list of all aobjs. 1251 */ 1252 1253 restart: 1254 simple_lock(&uao_list_lock); 1255 for (aobj = LIST_FIRST(&uao_list); 1256 aobj != NULL; 1257 aobj = nextaobj) { 1258 1259 /* 1260 * try to get the object lock, start all over if we fail. 1261 * most of the time we'll get the aobj lock, 1262 * so this should be a rare case. 1263 */ 1264 1265 if (!simple_lock_try(&aobj->u_obj.vmobjlock)) { 1266 simple_unlock(&uao_list_lock); 1267 goto restart; 1268 } 1269 1270 /* 1271 * add a ref to the aobj so it doesn't disappear 1272 * while we're working. 1273 */ 1274 1275 uao_reference_locked(&aobj->u_obj); 1276 1277 /* 1278 * now it's safe to unlock the uao list. 1279 */ 1280 1281 simple_unlock(&uao_list_lock); 1282 1283 /* 1284 * page in any pages in the swslot range. 1285 * if there's an error, abort and return the error. 1286 */ 1287 1288 rv = uao_pagein(aobj, startslot, endslot); 1289 if (rv) { 1290 uao_detach_locked(&aobj->u_obj); 1291 return rv; 1292 } 1293 1294 /* 1295 * we're done with this aobj. 1296 * relock the list and drop our ref on the aobj. 1297 */ 1298 1299 simple_lock(&uao_list_lock); 1300 nextaobj = LIST_NEXT(aobj, u_list); 1301 uao_detach_locked(&aobj->u_obj); 1302 } 1303 1304 /* 1305 * done with traversal, unlock the list 1306 */ 1307 simple_unlock(&uao_list_lock); 1308 return FALSE; 1309 } 1310 1311 1312 /* 1313 * page in any pages from aobj in the given range. 1314 * 1315 * => aobj must be locked and is returned locked. 1316 * => returns TRUE if pagein was aborted due to lack of memory. 1317 */ 1318 static boolean_t 1319 uao_pagein(struct uvm_aobj *aobj, int startslot, int endslot) 1320 { 1321 boolean_t rv; 1322 1323 if (UAO_USES_SWHASH(aobj)) { 1324 struct uao_swhash_elt *elt; 1325 int buck; 1326 1327 restart: 1328 for (buck = aobj->u_swhashmask; buck >= 0; buck--) { 1329 for (elt = LIST_FIRST(&aobj->u_swhash[buck]); 1330 elt != NULL; 1331 elt = LIST_NEXT(elt, list)) { 1332 int i; 1333 1334 for (i = 0; i < UAO_SWHASH_CLUSTER_SIZE; i++) { 1335 int slot = elt->slots[i]; 1336 1337 /* 1338 * if the slot isn't in range, skip it. 1339 */ 1340 1341 if (slot < startslot || 1342 slot >= endslot) { 1343 continue; 1344 } 1345 1346 /* 1347 * process the page, 1348 * the start over on this object 1349 * since the swhash elt 1350 * may have been freed. 1351 */ 1352 1353 rv = uao_pagein_page(aobj, 1354 UAO_SWHASH_ELT_PAGEIDX_BASE(elt) + i); 1355 if (rv) { 1356 return rv; 1357 } 1358 goto restart; 1359 } 1360 } 1361 } 1362 } else { 1363 int i; 1364 1365 for (i = 0; i < aobj->u_pages; i++) { 1366 int slot = aobj->u_swslots[i]; 1367 1368 /* 1369 * if the slot isn't in range, skip it 1370 */ 1371 1372 if (slot < startslot || slot >= endslot) { 1373 continue; 1374 } 1375 1376 /* 1377 * process the page. 1378 */ 1379 1380 rv = uao_pagein_page(aobj, i); 1381 if (rv) { 1382 return rv; 1383 } 1384 } 1385 } 1386 1387 return FALSE; 1388 } 1389 1390 /* 1391 * page in a page from an aobj. used for swap_off. 1392 * returns TRUE if pagein was aborted due to lack of memory. 1393 * 1394 * => aobj must be locked and is returned locked. 1395 */ 1396 1397 static boolean_t 1398 uao_pagein_page(struct uvm_aobj *aobj, int pageidx) 1399 { 1400 struct vm_page *pg; 1401 int rv, npages; 1402 1403 pg = NULL; 1404 npages = 1; 1405 /* locked: aobj */ 1406 rv = uao_get(&aobj->u_obj, pageidx << PAGE_SHIFT, 1407 &pg, &npages, 0, VM_PROT_READ|VM_PROT_WRITE, 0, PGO_SYNCIO); 1408 /* unlocked: aobj */ 1409 1410 /* 1411 * relock and finish up. 1412 */ 1413 1414 simple_lock(&aobj->u_obj.vmobjlock); 1415 switch (rv) { 1416 case 0: 1417 break; 1418 1419 case EIO: 1420 case ERESTART: 1421 1422 /* 1423 * nothing more to do on errors. 1424 * ERESTART can only mean that the anon was freed, 1425 * so again there's nothing to do. 1426 */ 1427 1428 return FALSE; 1429 1430 default: 1431 return TRUE; 1432 } 1433 1434 /* 1435 * ok, we've got the page now. 1436 * mark it as dirty, clear its swslot and un-busy it. 1437 */ 1438 uao_dropswap(&aobj->u_obj, pageidx); 1439 1440 /* 1441 * make sure it's on a page queue. 1442 */ 1443 uvm_lock_pageq(); 1444 if (pg->wire_count == 0) 1445 uvm_pageenqueue(pg); 1446 uvm_unlock_pageq(); 1447 1448 if (pg->flags & PG_WANTED) { 1449 wakeup(pg); 1450 } 1451 pg->flags &= ~(PG_WANTED|PG_BUSY|PG_CLEAN|PG_FAKE); 1452 UVM_PAGE_OWN(pg, NULL); 1453 1454 return FALSE; 1455 } 1456 1457 /* 1458 * uao_dropswap_range: drop swapslots in the range. 1459 * 1460 * => aobj must be locked and is returned locked. 1461 * => start is inclusive. end is exclusive. 1462 */ 1463 1464 void 1465 uao_dropswap_range(struct uvm_object *uobj, voff_t start, voff_t end) 1466 { 1467 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 1468 1469 LOCK_ASSERT(simple_lock_held(&uobj->vmobjlock)); 1470 1471 uao_dropswap_range1(aobj, start, end); 1472 } 1473 1474 static void 1475 uao_dropswap_range1(struct uvm_aobj *aobj, voff_t start, voff_t end) 1476 { 1477 int swpgonlydelta = 0; 1478 1479 if (end == 0) { 1480 end = INT64_MAX; 1481 } 1482 1483 if (UAO_USES_SWHASH(aobj)) { 1484 int i, hashbuckets = aobj->u_swhashmask + 1; 1485 voff_t taghi; 1486 voff_t taglo; 1487 1488 taglo = UAO_SWHASH_ELT_TAG(start); 1489 taghi = UAO_SWHASH_ELT_TAG(end); 1490 1491 for (i = 0; i < hashbuckets; i++) { 1492 struct uao_swhash_elt *elt, *next; 1493 1494 for (elt = LIST_FIRST(&aobj->u_swhash[i]); 1495 elt != NULL; 1496 elt = next) { 1497 int startidx, endidx; 1498 int j; 1499 1500 next = LIST_NEXT(elt, list); 1501 1502 if (elt->tag < taglo || taghi < elt->tag) { 1503 continue; 1504 } 1505 1506 if (elt->tag == taglo) { 1507 startidx = 1508 UAO_SWHASH_ELT_PAGESLOT_IDX(start); 1509 } else { 1510 startidx = 0; 1511 } 1512 1513 if (elt->tag == taghi) { 1514 endidx = 1515 UAO_SWHASH_ELT_PAGESLOT_IDX(end); 1516 } else { 1517 endidx = UAO_SWHASH_CLUSTER_SIZE; 1518 } 1519 1520 for (j = startidx; j < endidx; j++) { 1521 int slot = elt->slots[j]; 1522 1523 KASSERT(uvm_pagelookup(&aobj->u_obj, 1524 (UAO_SWHASH_ELT_PAGEIDX_BASE(elt) 1525 + j) << PAGE_SHIFT) == NULL); 1526 if (slot > 0) { 1527 uvm_swap_free(slot, 1); 1528 swpgonlydelta++; 1529 KASSERT(elt->count > 0); 1530 elt->slots[j] = 0; 1531 elt->count--; 1532 } 1533 } 1534 1535 if (elt->count == 0) { 1536 LIST_REMOVE(elt, list); 1537 pool_put(&uao_swhash_elt_pool, elt); 1538 } 1539 } 1540 } 1541 } else { 1542 int i; 1543 1544 if (aobj->u_pages < end) { 1545 end = aobj->u_pages; 1546 } 1547 for (i = start; i < end; i++) { 1548 int slot = aobj->u_swslots[i]; 1549 1550 if (slot > 0) { 1551 uvm_swap_free(slot, 1); 1552 swpgonlydelta++; 1553 } 1554 } 1555 } 1556 1557 /* 1558 * adjust the counter of pages only in swap for all 1559 * the swap slots we've freed. 1560 */ 1561 1562 if (swpgonlydelta > 0) { 1563 simple_lock(&uvm.swap_data_lock); 1564 KASSERT(uvmexp.swpgonly >= swpgonlydelta); 1565 uvmexp.swpgonly -= swpgonlydelta; 1566 simple_unlock(&uvm.swap_data_lock); 1567 } 1568 } 1569 1570 #endif /* defined(VMSWAP) */ 1571