1 /* $NetBSD: uvm_aobj.c,v 1.97 2008/01/18 10:48:23 yamt 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 1.97 2008/01/18 10:48:23 yamt 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 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 /* 123 * uao_swhash_elt: when a hash table is being used, this structure defines 124 * the format of an entry in the bucket list. 125 */ 126 127 struct uao_swhash_elt { 128 LIST_ENTRY(uao_swhash_elt) list; /* the hash list */ 129 voff_t tag; /* our 'tag' */ 130 int count; /* our number of active slots */ 131 int slots[UAO_SWHASH_CLUSTER_SIZE]; /* the slots */ 132 }; 133 134 /* 135 * uao_swhash: the swap hash table structure 136 */ 137 138 LIST_HEAD(uao_swhash, uao_swhash_elt); 139 140 /* 141 * uao_swhash_elt_pool: pool of uao_swhash_elt structures 142 * NOTE: Pages for this pool must not come from a pageable kernel map! 143 */ 144 POOL_INIT(uao_swhash_elt_pool, sizeof(struct uao_swhash_elt), 0, 0, 0, 145 "uaoeltpl", NULL, IPL_VM); 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 * uvm_aobj_pool: pool of uvm_aobj structures 171 */ 172 POOL_INIT(uvm_aobj_pool, sizeof(struct uvm_aobj), 0, 0, 0, "aobjpl", 173 &pool_allocator_nointr, IPL_NONE); 174 175 MALLOC_DEFINE(M_UVMAOBJ, "UVM aobj", "UVM aobj and related structures"); 176 177 /* 178 * local functions 179 */ 180 181 static void uao_free(struct uvm_aobj *); 182 static int uao_get(struct uvm_object *, voff_t, struct vm_page **, 183 int *, int, vm_prot_t, int, int); 184 static int uao_put(struct uvm_object *, voff_t, voff_t, int); 185 186 #if defined(VMSWAP) 187 static struct uao_swhash_elt *uao_find_swhash_elt 188 (struct uvm_aobj *, int, bool); 189 190 static bool uao_pagein(struct uvm_aobj *, int, int); 191 static bool uao_pagein_page(struct uvm_aobj *, int); 192 static void uao_dropswap_range1(struct uvm_aobj *, voff_t, voff_t); 193 #endif /* defined(VMSWAP) */ 194 195 /* 196 * aobj_pager 197 * 198 * note that some functions (e.g. put) are handled elsewhere 199 */ 200 201 const struct uvm_pagerops aobj_pager = { 202 .pgo_reference = uao_reference, 203 .pgo_detach = uao_detach, 204 .pgo_get = uao_get, 205 .pgo_put = uao_put, 206 }; 207 208 /* 209 * uao_list: global list of active aobjs, locked by uao_list_lock 210 */ 211 212 static LIST_HEAD(aobjlist, uvm_aobj) uao_list; 213 static kmutex_t uao_list_lock; 214 215 /* 216 * functions 217 */ 218 219 /* 220 * hash table/array related functions 221 */ 222 223 #if defined(VMSWAP) 224 225 /* 226 * uao_find_swhash_elt: find (or create) a hash table entry for a page 227 * offset. 228 * 229 * => the object should be locked by the caller 230 */ 231 232 static struct uao_swhash_elt * 233 uao_find_swhash_elt(struct uvm_aobj *aobj, int pageidx, bool create) 234 { 235 struct uao_swhash *swhash; 236 struct uao_swhash_elt *elt; 237 voff_t page_tag; 238 239 swhash = UAO_SWHASH_HASH(aobj, pageidx); 240 page_tag = UAO_SWHASH_ELT_TAG(pageidx); 241 242 /* 243 * now search the bucket for the requested tag 244 */ 245 246 LIST_FOREACH(elt, swhash, list) { 247 if (elt->tag == page_tag) { 248 return elt; 249 } 250 } 251 if (!create) { 252 return NULL; 253 } 254 255 /* 256 * allocate a new entry for the bucket and init/insert it in 257 */ 258 259 elt = pool_get(&uao_swhash_elt_pool, PR_NOWAIT); 260 if (elt == NULL) { 261 return NULL; 262 } 263 LIST_INSERT_HEAD(swhash, elt, list); 264 elt->tag = page_tag; 265 elt->count = 0; 266 memset(elt->slots, 0, sizeof(elt->slots)); 267 return elt; 268 } 269 270 /* 271 * uao_find_swslot: find the swap slot number for an aobj/pageidx 272 * 273 * => object must be locked by caller 274 */ 275 276 int 277 uao_find_swslot(struct uvm_object *uobj, int pageidx) 278 { 279 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 280 struct uao_swhash_elt *elt; 281 282 /* 283 * if noswap flag is set, then we never return a slot 284 */ 285 286 if (aobj->u_flags & UAO_FLAG_NOSWAP) 287 return(0); 288 289 /* 290 * if hashing, look in hash table. 291 */ 292 293 if (UAO_USES_SWHASH(aobj)) { 294 elt = uao_find_swhash_elt(aobj, pageidx, false); 295 if (elt) 296 return(UAO_SWHASH_ELT_PAGESLOT(elt, pageidx)); 297 else 298 return(0); 299 } 300 301 /* 302 * otherwise, look in the array 303 */ 304 305 return(aobj->u_swslots[pageidx]); 306 } 307 308 /* 309 * uao_set_swslot: set the swap slot for a page in an aobj. 310 * 311 * => setting a slot to zero frees the slot 312 * => object must be locked by caller 313 * => we return the old slot number, or -1 if we failed to allocate 314 * memory to record the new slot number 315 */ 316 317 int 318 uao_set_swslot(struct uvm_object *uobj, int pageidx, int slot) 319 { 320 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 321 struct uao_swhash_elt *elt; 322 int oldslot; 323 UVMHIST_FUNC("uao_set_swslot"); UVMHIST_CALLED(pdhist); 324 UVMHIST_LOG(pdhist, "aobj %p pageidx %d slot %d", 325 aobj, pageidx, slot, 0); 326 327 /* 328 * if noswap flag is set, then we can't set a non-zero slot. 329 */ 330 331 if (aobj->u_flags & UAO_FLAG_NOSWAP) { 332 if (slot == 0) 333 return(0); 334 335 printf("uao_set_swslot: uobj = %p\n", uobj); 336 panic("uao_set_swslot: NOSWAP object"); 337 } 338 339 /* 340 * are we using a hash table? if so, add it in the hash. 341 */ 342 343 if (UAO_USES_SWHASH(aobj)) { 344 345 /* 346 * Avoid allocating an entry just to free it again if 347 * the page had not swap slot in the first place, and 348 * we are freeing. 349 */ 350 351 elt = uao_find_swhash_elt(aobj, pageidx, slot != 0); 352 if (elt == NULL) { 353 return slot ? -1 : 0; 354 } 355 356 oldslot = UAO_SWHASH_ELT_PAGESLOT(elt, pageidx); 357 UAO_SWHASH_ELT_PAGESLOT(elt, pageidx) = slot; 358 359 /* 360 * now adjust the elt's reference counter and free it if we've 361 * dropped it to zero. 362 */ 363 364 if (slot) { 365 if (oldslot == 0) 366 elt->count++; 367 } else { 368 if (oldslot) 369 elt->count--; 370 371 if (elt->count == 0) { 372 LIST_REMOVE(elt, list); 373 pool_put(&uao_swhash_elt_pool, elt); 374 } 375 } 376 } else { 377 /* we are using an array */ 378 oldslot = aobj->u_swslots[pageidx]; 379 aobj->u_swslots[pageidx] = slot; 380 } 381 return (oldslot); 382 } 383 384 #endif /* defined(VMSWAP) */ 385 386 /* 387 * end of hash/array functions 388 */ 389 390 /* 391 * uao_free: free all resources held by an aobj, and then free the aobj 392 * 393 * => the aobj should be dead 394 */ 395 396 static void 397 uao_free(struct uvm_aobj *aobj) 398 { 399 int swpgonlydelta = 0; 400 401 402 #if defined(VMSWAP) 403 uao_dropswap_range1(aobj, 0, 0); 404 #endif /* defined(VMSWAP) */ 405 406 mutex_exit(&aobj->u_obj.vmobjlock); 407 408 #if defined(VMSWAP) 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 UVM_OBJ_DESTROY(&aobj->u_obj); 431 pool_put(&uvm_aobj_pool, aobj); 432 433 /* 434 * adjust the counter of pages only in swap for all 435 * the swap slots we've freed. 436 */ 437 438 if (swpgonlydelta > 0) { 439 mutex_enter(&uvm_swap_data_lock); 440 KASSERT(uvmexp.swpgonly >= swpgonlydelta); 441 uvmexp.swpgonly -= swpgonlydelta; 442 mutex_exit(&uvm_swap_data_lock); 443 } 444 } 445 446 /* 447 * pager functions 448 */ 449 450 /* 451 * uao_create: create an aobj of the given size and return its uvm_object. 452 * 453 * => for normal use, flags are always zero 454 * => for the kernel object, the flags are: 455 * UAO_FLAG_KERNOBJ - allocate the kernel object (can only happen once) 456 * UAO_FLAG_KERNSWAP - enable swapping of kernel object (" ") 457 */ 458 459 struct uvm_object * 460 uao_create(vsize_t size, int flags) 461 { 462 static struct uvm_aobj kernel_object_store; 463 static int kobj_alloced = 0; 464 pgoff_t pages = round_page(size) >> PAGE_SHIFT; 465 struct uvm_aobj *aobj; 466 int refs; 467 468 /* 469 * malloc a new aobj unless we are asked for the kernel object 470 */ 471 472 if (flags & UAO_FLAG_KERNOBJ) { 473 KASSERT(!kobj_alloced); 474 aobj = &kernel_object_store; 475 aobj->u_pages = pages; 476 aobj->u_flags = UAO_FLAG_NOSWAP; 477 refs = UVM_OBJ_KERN; 478 kobj_alloced = UAO_FLAG_KERNOBJ; 479 } else if (flags & UAO_FLAG_KERNSWAP) { 480 KASSERT(kobj_alloced == UAO_FLAG_KERNOBJ); 481 aobj = &kernel_object_store; 482 kobj_alloced = UAO_FLAG_KERNSWAP; 483 refs = 0xdeadbeaf; /* XXX: gcc */ 484 } else { 485 aobj = pool_get(&uvm_aobj_pool, PR_WAITOK); 486 aobj->u_pages = pages; 487 aobj->u_flags = 0; 488 refs = 1; 489 } 490 491 /* 492 * allocate hash/array if necessary 493 * 494 * note: in the KERNSWAP case no need to worry about locking since 495 * we are still booting we should be the only thread around. 496 */ 497 498 if (flags == 0 || (flags & UAO_FLAG_KERNSWAP) != 0) { 499 #if defined(VMSWAP) 500 int mflags = (flags & UAO_FLAG_KERNSWAP) != 0 ? 501 M_NOWAIT : M_WAITOK; 502 503 /* allocate hash table or array depending on object size */ 504 if (UAO_USES_SWHASH(aobj)) { 505 aobj->u_swhash = hashinit(UAO_SWHASH_BUCKETS(aobj), 506 HASH_LIST, M_UVMAOBJ, mflags, &aobj->u_swhashmask); 507 if (aobj->u_swhash == NULL) 508 panic("uao_create: hashinit swhash failed"); 509 } else { 510 aobj->u_swslots = malloc(pages * sizeof(int), 511 M_UVMAOBJ, mflags); 512 if (aobj->u_swslots == NULL) 513 panic("uao_create: malloc swslots failed"); 514 memset(aobj->u_swslots, 0, pages * sizeof(int)); 515 } 516 #endif /* defined(VMSWAP) */ 517 518 if (flags) { 519 aobj->u_flags &= ~UAO_FLAG_NOSWAP; /* clear noswap */ 520 return(&aobj->u_obj); 521 } 522 } 523 524 /* 525 * init aobj fields 526 */ 527 528 UVM_OBJ_INIT(&aobj->u_obj, &aobj_pager, refs); 529 530 /* 531 * now that aobj is ready, add it to the global list 532 */ 533 534 mutex_enter(&uao_list_lock); 535 LIST_INSERT_HEAD(&uao_list, aobj, u_list); 536 mutex_exit(&uao_list_lock); 537 return(&aobj->u_obj); 538 } 539 540 541 542 /* 543 * uao_init: set up aobj pager subsystem 544 * 545 * => called at boot time from uvm_pager_init() 546 */ 547 548 void 549 uao_init(void) 550 { 551 static int uao_initialized; 552 553 if (uao_initialized) 554 return; 555 uao_initialized = true; 556 LIST_INIT(&uao_list); 557 mutex_init(&uao_list_lock, MUTEX_DEFAULT, IPL_NONE); 558 } 559 560 /* 561 * uao_reference: add a ref to an aobj 562 * 563 * => aobj must be unlocked 564 * => just lock it and call the locked version 565 */ 566 567 void 568 uao_reference(struct uvm_object *uobj) 569 { 570 mutex_enter(&uobj->vmobjlock); 571 uao_reference_locked(uobj); 572 mutex_exit(&uobj->vmobjlock); 573 } 574 575 /* 576 * uao_reference_locked: add a ref to an aobj that is already locked 577 * 578 * => aobj must be locked 579 * this needs to be separate from the normal routine 580 * since sometimes we need to add a reference to an aobj when 581 * it's already locked. 582 */ 583 584 void 585 uao_reference_locked(struct uvm_object *uobj) 586 { 587 UVMHIST_FUNC("uao_reference"); UVMHIST_CALLED(maphist); 588 589 /* 590 * kernel_object already has plenty of references, leave it alone. 591 */ 592 593 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) 594 return; 595 596 uobj->uo_refs++; 597 UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)", 598 uobj, uobj->uo_refs,0,0); 599 } 600 601 /* 602 * uao_detach: drop a reference to an aobj 603 * 604 * => aobj must be unlocked 605 * => just lock it and call the locked version 606 */ 607 608 void 609 uao_detach(struct uvm_object *uobj) 610 { 611 mutex_enter(&uobj->vmobjlock); 612 uao_detach_locked(uobj); 613 } 614 615 /* 616 * uao_detach_locked: drop a reference to an aobj 617 * 618 * => aobj must be locked, and is unlocked (or freed) upon return. 619 * this needs to be separate from the normal routine 620 * since sometimes we need to detach from an aobj when 621 * it's already locked. 622 */ 623 624 void 625 uao_detach_locked(struct uvm_object *uobj) 626 { 627 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 628 struct vm_page *pg; 629 UVMHIST_FUNC("uao_detach"); UVMHIST_CALLED(maphist); 630 631 /* 632 * detaching from kernel_object is a noop. 633 */ 634 635 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) { 636 mutex_exit(&uobj->vmobjlock); 637 return; 638 } 639 640 UVMHIST_LOG(maphist," (uobj=0x%x) ref=%d", uobj,uobj->uo_refs,0,0); 641 uobj->uo_refs--; 642 if (uobj->uo_refs) { 643 mutex_exit(&uobj->vmobjlock); 644 UVMHIST_LOG(maphist, "<- done (rc>0)", 0,0,0,0); 645 return; 646 } 647 648 /* 649 * remove the aobj from the global list. 650 */ 651 652 mutex_enter(&uao_list_lock); 653 LIST_REMOVE(aobj, u_list); 654 mutex_exit(&uao_list_lock); 655 656 /* 657 * free all the pages left in the aobj. for each page, 658 * when the page is no longer busy (and thus after any disk i/o that 659 * it's involved in is complete), release any swap resources and 660 * free the page itself. 661 */ 662 663 mutex_enter(&uvm_pageqlock); 664 while ((pg = TAILQ_FIRST(&uobj->memq)) != NULL) { 665 pmap_page_protect(pg, VM_PROT_NONE); 666 if (pg->flags & PG_BUSY) { 667 pg->flags |= PG_WANTED; 668 mutex_exit(&uvm_pageqlock); 669 UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, false, 670 "uao_det", 0); 671 mutex_enter(&uobj->vmobjlock); 672 mutex_enter(&uvm_pageqlock); 673 continue; 674 } 675 uao_dropswap(&aobj->u_obj, pg->offset >> PAGE_SHIFT); 676 uvm_pagefree(pg); 677 } 678 mutex_exit(&uvm_pageqlock); 679 680 /* 681 * finally, free the aobj itself. 682 */ 683 684 uao_free(aobj); 685 } 686 687 /* 688 * uao_put: flush pages out of a uvm object 689 * 690 * => object should be locked by caller. we may _unlock_ the object 691 * if (and only if) we need to clean a page (PGO_CLEANIT). 692 * XXXJRT Currently, however, we don't. In the case of cleaning 693 * XXXJRT a page, we simply just deactivate it. Should probably 694 * XXXJRT handle this better, in the future (although "flushing" 695 * XXXJRT anonymous memory isn't terribly important). 696 * => if PGO_CLEANIT is not set, then we will neither unlock the object 697 * or block. 698 * => if PGO_ALLPAGE is set, then all pages in the object are valid targets 699 * for flushing. 700 * => NOTE: we rely on the fact that the object's memq is a TAILQ and 701 * that new pages are inserted on the tail end of the list. thus, 702 * we can make a complete pass through the object in one go by starting 703 * at the head and working towards the tail (new pages are put in 704 * front of us). 705 * => NOTE: we are allowed to lock the page queues, so the caller 706 * must not be holding the lock on them [e.g. pagedaemon had 707 * better not call us with the queues locked] 708 * => we return 0 unless we encountered some sort of I/O error 709 * XXXJRT currently never happens, as we never directly initiate 710 * XXXJRT I/O 711 * 712 * note on page traversal: 713 * we can traverse the pages in an object either by going down the 714 * linked list in "uobj->memq", or we can go over the address range 715 * by page doing hash table lookups for each address. depending 716 * on how many pages are in the object it may be cheaper to do one 717 * or the other. we set "by_list" to true if we are using memq. 718 * if the cost of a hash lookup was equal to the cost of the list 719 * traversal we could compare the number of pages in the start->stop 720 * range to the total number of pages in the object. however, it 721 * seems that a hash table lookup is more expensive than the linked 722 * list traversal, so we multiply the number of pages in the 723 * start->stop range by a penalty which we define below. 724 */ 725 726 static int 727 uao_put(struct uvm_object *uobj, voff_t start, voff_t stop, int flags) 728 { 729 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 730 struct vm_page *pg, *nextpg, curmp, endmp; 731 bool by_list; 732 voff_t curoff; 733 UVMHIST_FUNC("uao_put"); UVMHIST_CALLED(maphist); 734 735 KASSERT(mutex_owned(&uobj->vmobjlock)); 736 737 curoff = 0; 738 if (flags & PGO_ALLPAGES) { 739 start = 0; 740 stop = aobj->u_pages << PAGE_SHIFT; 741 by_list = true; /* always go by the list */ 742 } else { 743 start = trunc_page(start); 744 if (stop == 0) { 745 stop = aobj->u_pages << PAGE_SHIFT; 746 } else { 747 stop = round_page(stop); 748 } 749 if (stop > (aobj->u_pages << PAGE_SHIFT)) { 750 printf("uao_flush: strange, got an out of range " 751 "flush (fixed)\n"); 752 stop = aobj->u_pages << PAGE_SHIFT; 753 } 754 by_list = (uobj->uo_npages <= 755 ((stop - start) >> PAGE_SHIFT) * UVM_PAGE_HASH_PENALTY); 756 } 757 UVMHIST_LOG(maphist, 758 " flush start=0x%lx, stop=0x%x, by_list=%d, flags=0x%x", 759 start, stop, by_list, flags); 760 761 /* 762 * Don't need to do any work here if we're not freeing 763 * or deactivating pages. 764 */ 765 766 if ((flags & (PGO_DEACTIVATE|PGO_FREE)) == 0) { 767 mutex_exit(&uobj->vmobjlock); 768 return 0; 769 } 770 771 /* 772 * Initialize the marker pages. See the comment in 773 * genfs_putpages() also. 774 */ 775 776 curmp.uobject = uobj; 777 curmp.offset = (voff_t)-1; 778 curmp.flags = PG_BUSY; 779 endmp.uobject = uobj; 780 endmp.offset = (voff_t)-1; 781 endmp.flags = PG_BUSY; 782 783 /* 784 * now do it. note: we must update nextpg in the body of loop or we 785 * will get stuck. we need to use nextpg if we'll traverse the list 786 * because we may free "pg" before doing the next loop. 787 */ 788 789 if (by_list) { 790 TAILQ_INSERT_TAIL(&uobj->memq, &endmp, listq); 791 nextpg = TAILQ_FIRST(&uobj->memq); 792 uvm_lwp_hold(curlwp); 793 } else { 794 curoff = start; 795 nextpg = NULL; /* Quell compiler warning */ 796 } 797 798 mutex_enter(&uvm_pageqlock); 799 800 /* locked: both page queues and uobj */ 801 for (;;) { 802 if (by_list) { 803 pg = nextpg; 804 if (pg == &endmp) 805 break; 806 nextpg = TAILQ_NEXT(pg, listq); 807 if (pg->offset < start || pg->offset >= stop) 808 continue; 809 } else { 810 if (curoff < stop) { 811 pg = uvm_pagelookup(uobj, curoff); 812 curoff += PAGE_SIZE; 813 } else 814 break; 815 if (pg == NULL) 816 continue; 817 } 818 switch (flags & (PGO_CLEANIT|PGO_FREE|PGO_DEACTIVATE)) { 819 820 /* 821 * XXX In these first 3 cases, we always just 822 * XXX deactivate the page. We may want to 823 * XXX handle the different cases more specifically 824 * XXX in the future. 825 */ 826 827 case PGO_CLEANIT|PGO_FREE: 828 case PGO_CLEANIT|PGO_DEACTIVATE: 829 case PGO_DEACTIVATE: 830 deactivate_it: 831 /* skip the page if it's wired */ 832 if (pg->wire_count != 0) 833 continue; 834 835 /* ...and deactivate the page. */ 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 mutex_exit(&uvm_pageqlock); 861 UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, 0, 862 "uao_put", 0); 863 mutex_enter(&uobj->vmobjlock); 864 mutex_enter(&uvm_pageqlock); 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 mutex_exit(&uvm_pageqlock); 886 if (by_list) { 887 TAILQ_REMOVE(&uobj->memq, &endmp, listq); 888 uvm_lwp_rele(curlwp); 889 } 890 mutex_exit(&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 bool 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 mutex_exit(&uobj->vmobjlock); 1065 UVMHIST_LOG(pdhist, 1066 "sleeping, ptmp == NULL\n",0,0,0,0); 1067 uvm_wait("uao_getpage"); 1068 mutex_enter(&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 mutex_enter(&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 mutex_exit(&uobj->vmobjlock); 1151 error = uvm_swap_get(ptmp, swslot, PGO_SYNCIO); 1152 mutex_enter(&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 mutex_enter(&uvm_pageqlock); 1178 uvm_pagefree(ptmp); 1179 mutex_exit(&uvm_pageqlock); 1180 mutex_exit(&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 mutex_exit(&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 bool 1245 uao_swap_off(int startslot, int endslot) 1246 { 1247 struct uvm_aobj *aobj, *nextaobj; 1248 bool rv; 1249 1250 /* 1251 * walk the list of all aobjs. 1252 */ 1253 1254 restart: 1255 mutex_enter(&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 (!mutex_tryenter(&aobj->u_obj.vmobjlock)) { 1267 mutex_exit(&uao_list_lock); 1268 /* XXX Better than yielding but inadequate. */ 1269 kpause("livelock", false, 1, NULL); 1270 goto restart; 1271 } 1272 1273 /* 1274 * add a ref to the aobj so it doesn't disappear 1275 * while we're working. 1276 */ 1277 1278 uao_reference_locked(&aobj->u_obj); 1279 1280 /* 1281 * now it's safe to unlock the uao list. 1282 */ 1283 1284 mutex_exit(&uao_list_lock); 1285 1286 /* 1287 * page in any pages in the swslot range. 1288 * if there's an error, abort and return the error. 1289 */ 1290 1291 rv = uao_pagein(aobj, startslot, endslot); 1292 if (rv) { 1293 uao_detach_locked(&aobj->u_obj); 1294 return rv; 1295 } 1296 1297 /* 1298 * we're done with this aobj. 1299 * relock the list and drop our ref on the aobj. 1300 */ 1301 1302 mutex_enter(&uao_list_lock); 1303 nextaobj = LIST_NEXT(aobj, u_list); 1304 uao_detach_locked(&aobj->u_obj); 1305 } 1306 1307 /* 1308 * done with traversal, unlock the list 1309 */ 1310 mutex_exit(&uao_list_lock); 1311 return false; 1312 } 1313 1314 1315 /* 1316 * page in any pages from aobj in the given range. 1317 * 1318 * => aobj must be locked and is returned locked. 1319 * => returns true if pagein was aborted due to lack of memory. 1320 */ 1321 static bool 1322 uao_pagein(struct uvm_aobj *aobj, int startslot, int endslot) 1323 { 1324 bool rv; 1325 1326 if (UAO_USES_SWHASH(aobj)) { 1327 struct uao_swhash_elt *elt; 1328 int buck; 1329 1330 restart: 1331 for (buck = aobj->u_swhashmask; buck >= 0; buck--) { 1332 for (elt = LIST_FIRST(&aobj->u_swhash[buck]); 1333 elt != NULL; 1334 elt = LIST_NEXT(elt, list)) { 1335 int i; 1336 1337 for (i = 0; i < UAO_SWHASH_CLUSTER_SIZE; i++) { 1338 int slot = elt->slots[i]; 1339 1340 /* 1341 * if the slot isn't in range, skip it. 1342 */ 1343 1344 if (slot < startslot || 1345 slot >= endslot) { 1346 continue; 1347 } 1348 1349 /* 1350 * process the page, 1351 * the start over on this object 1352 * since the swhash elt 1353 * may have been freed. 1354 */ 1355 1356 rv = uao_pagein_page(aobj, 1357 UAO_SWHASH_ELT_PAGEIDX_BASE(elt) + i); 1358 if (rv) { 1359 return rv; 1360 } 1361 goto restart; 1362 } 1363 } 1364 } 1365 } else { 1366 int i; 1367 1368 for (i = 0; i < aobj->u_pages; i++) { 1369 int slot = aobj->u_swslots[i]; 1370 1371 /* 1372 * if the slot isn't in range, skip it 1373 */ 1374 1375 if (slot < startslot || slot >= endslot) { 1376 continue; 1377 } 1378 1379 /* 1380 * process the page. 1381 */ 1382 1383 rv = uao_pagein_page(aobj, i); 1384 if (rv) { 1385 return rv; 1386 } 1387 } 1388 } 1389 1390 return false; 1391 } 1392 1393 /* 1394 * page in a page from an aobj. used for swap_off. 1395 * returns true if pagein was aborted due to lack of memory. 1396 * 1397 * => aobj must be locked and is returned locked. 1398 */ 1399 1400 static bool 1401 uao_pagein_page(struct uvm_aobj *aobj, int pageidx) 1402 { 1403 struct vm_page *pg; 1404 int rv, npages; 1405 1406 pg = NULL; 1407 npages = 1; 1408 /* locked: aobj */ 1409 rv = uao_get(&aobj->u_obj, pageidx << PAGE_SHIFT, 1410 &pg, &npages, 0, VM_PROT_READ|VM_PROT_WRITE, 0, PGO_SYNCIO); 1411 /* unlocked: aobj */ 1412 1413 /* 1414 * relock and finish up. 1415 */ 1416 1417 mutex_enter(&aobj->u_obj.vmobjlock); 1418 switch (rv) { 1419 case 0: 1420 break; 1421 1422 case EIO: 1423 case ERESTART: 1424 1425 /* 1426 * nothing more to do on errors. 1427 * ERESTART can only mean that the anon was freed, 1428 * so again there's nothing to do. 1429 */ 1430 1431 return false; 1432 1433 default: 1434 return true; 1435 } 1436 1437 /* 1438 * ok, we've got the page now. 1439 * mark it as dirty, clear its swslot and un-busy it. 1440 */ 1441 uao_dropswap(&aobj->u_obj, pageidx); 1442 1443 /* 1444 * make sure it's on a page queue. 1445 */ 1446 mutex_enter(&uvm_pageqlock); 1447 if (pg->wire_count == 0) 1448 uvm_pageenqueue(pg); 1449 mutex_exit(&uvm_pageqlock); 1450 1451 if (pg->flags & PG_WANTED) { 1452 wakeup(pg); 1453 } 1454 pg->flags &= ~(PG_WANTED|PG_BUSY|PG_CLEAN|PG_FAKE); 1455 UVM_PAGE_OWN(pg, NULL); 1456 1457 return false; 1458 } 1459 1460 /* 1461 * uao_dropswap_range: drop swapslots in the range. 1462 * 1463 * => aobj must be locked and is returned locked. 1464 * => start is inclusive. end is exclusive. 1465 */ 1466 1467 void 1468 uao_dropswap_range(struct uvm_object *uobj, voff_t start, voff_t end) 1469 { 1470 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 1471 1472 KASSERT(mutex_owned(&uobj->vmobjlock)); 1473 1474 uao_dropswap_range1(aobj, start, end); 1475 } 1476 1477 static void 1478 uao_dropswap_range1(struct uvm_aobj *aobj, voff_t start, voff_t end) 1479 { 1480 int swpgonlydelta = 0; 1481 1482 if (end == 0) { 1483 end = INT64_MAX; 1484 } 1485 1486 if (UAO_USES_SWHASH(aobj)) { 1487 int i, hashbuckets = aobj->u_swhashmask + 1; 1488 voff_t taghi; 1489 voff_t taglo; 1490 1491 taglo = UAO_SWHASH_ELT_TAG(start); 1492 taghi = UAO_SWHASH_ELT_TAG(end); 1493 1494 for (i = 0; i < hashbuckets; i++) { 1495 struct uao_swhash_elt *elt, *next; 1496 1497 for (elt = LIST_FIRST(&aobj->u_swhash[i]); 1498 elt != NULL; 1499 elt = next) { 1500 int startidx, endidx; 1501 int j; 1502 1503 next = LIST_NEXT(elt, list); 1504 1505 if (elt->tag < taglo || taghi < elt->tag) { 1506 continue; 1507 } 1508 1509 if (elt->tag == taglo) { 1510 startidx = 1511 UAO_SWHASH_ELT_PAGESLOT_IDX(start); 1512 } else { 1513 startidx = 0; 1514 } 1515 1516 if (elt->tag == taghi) { 1517 endidx = 1518 UAO_SWHASH_ELT_PAGESLOT_IDX(end); 1519 } else { 1520 endidx = UAO_SWHASH_CLUSTER_SIZE; 1521 } 1522 1523 for (j = startidx; j < endidx; j++) { 1524 int slot = elt->slots[j]; 1525 1526 KASSERT(uvm_pagelookup(&aobj->u_obj, 1527 (UAO_SWHASH_ELT_PAGEIDX_BASE(elt) 1528 + j) << PAGE_SHIFT) == NULL); 1529 if (slot > 0) { 1530 uvm_swap_free(slot, 1); 1531 swpgonlydelta++; 1532 KASSERT(elt->count > 0); 1533 elt->slots[j] = 0; 1534 elt->count--; 1535 } 1536 } 1537 1538 if (elt->count == 0) { 1539 LIST_REMOVE(elt, list); 1540 pool_put(&uao_swhash_elt_pool, elt); 1541 } 1542 } 1543 } 1544 } else { 1545 int i; 1546 1547 if (aobj->u_pages < end) { 1548 end = aobj->u_pages; 1549 } 1550 for (i = start; i < end; i++) { 1551 int slot = aobj->u_swslots[i]; 1552 1553 if (slot > 0) { 1554 uvm_swap_free(slot, 1); 1555 swpgonlydelta++; 1556 } 1557 } 1558 } 1559 1560 /* 1561 * adjust the counter of pages only in swap for all 1562 * the swap slots we've freed. 1563 */ 1564 1565 if (swpgonlydelta > 0) { 1566 mutex_enter(&uvm_swap_data_lock); 1567 KASSERT(uvmexp.swpgonly >= swpgonlydelta); 1568 uvmexp.swpgonly -= swpgonlydelta; 1569 mutex_exit(&uvm_swap_data_lock); 1570 } 1571 } 1572 1573 #endif /* defined(VMSWAP) */ 1574