1 /* $NetBSD: uvm_aobj.c,v 1.108 2009/10/21 21:12:07 rmind 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 1.108 2009/10/21 21:12:07 rmind 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 /* 323 * if noswap flag is set, then we can't set a non-zero slot. 324 */ 325 326 if (aobj->u_flags & UAO_FLAG_NOSWAP) { 327 if (slot == 0) 328 return(0); 329 330 printf("uao_set_swslot: uobj = %p\n", uobj); 331 panic("uao_set_swslot: NOSWAP object"); 332 } 333 334 /* 335 * are we using a hash table? if so, add it in the hash. 336 */ 337 338 if (UAO_USES_SWHASH(aobj)) { 339 340 /* 341 * Avoid allocating an entry just to free it again if 342 * the page had not swap slot in the first place, and 343 * we are freeing. 344 */ 345 346 elt = uao_find_swhash_elt(aobj, pageidx, slot != 0); 347 if (elt == NULL) { 348 return slot ? -1 : 0; 349 } 350 351 oldslot = UAO_SWHASH_ELT_PAGESLOT(elt, pageidx); 352 UAO_SWHASH_ELT_PAGESLOT(elt, pageidx) = slot; 353 354 /* 355 * now adjust the elt's reference counter and free it if we've 356 * dropped it to zero. 357 */ 358 359 if (slot) { 360 if (oldslot == 0) 361 elt->count++; 362 } else { 363 if (oldslot) 364 elt->count--; 365 366 if (elt->count == 0) { 367 LIST_REMOVE(elt, list); 368 pool_put(&uao_swhash_elt_pool, elt); 369 } 370 } 371 } else { 372 /* we are using an array */ 373 oldslot = aobj->u_swslots[pageidx]; 374 aobj->u_swslots[pageidx] = slot; 375 } 376 return (oldslot); 377 } 378 379 #endif /* defined(VMSWAP) */ 380 381 /* 382 * end of hash/array functions 383 */ 384 385 /* 386 * uao_free: free all resources held by an aobj, and then free the aobj 387 * 388 * => the aobj should be dead 389 */ 390 391 static void 392 uao_free(struct uvm_aobj *aobj) 393 { 394 int swpgonlydelta = 0; 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 * adjust the counter of pages only in swap for all 430 * the swap slots we've freed. 431 */ 432 433 if (swpgonlydelta > 0) { 434 mutex_enter(&uvm_swap_data_lock); 435 KASSERT(uvmexp.swpgonly >= swpgonlydelta); 436 uvmexp.swpgonly -= swpgonlydelta; 437 mutex_exit(&uvm_swap_data_lock); 438 } 439 } 440 441 /* 442 * pager functions 443 */ 444 445 /* 446 * uao_create: create an aobj of the given size and return its uvm_object. 447 * 448 * => for normal use, flags are always zero 449 * => for the kernel object, the flags are: 450 * UAO_FLAG_KERNOBJ - allocate the kernel object (can only happen once) 451 * UAO_FLAG_KERNSWAP - enable swapping of kernel object (" ") 452 */ 453 454 struct uvm_object * 455 uao_create(vsize_t size, int flags) 456 { 457 static struct uvm_aobj kernel_object_store; 458 static int kobj_alloced = 0; 459 pgoff_t pages = round_page(size) >> PAGE_SHIFT; 460 struct uvm_aobj *aobj; 461 int refs; 462 463 /* 464 * malloc a new aobj unless we are asked for the kernel object 465 */ 466 467 if (flags & UAO_FLAG_KERNOBJ) { 468 KASSERT(!kobj_alloced); 469 aobj = &kernel_object_store; 470 aobj->u_pages = pages; 471 aobj->u_flags = UAO_FLAG_NOSWAP; 472 refs = UVM_OBJ_KERN; 473 kobj_alloced = UAO_FLAG_KERNOBJ; 474 } else if (flags & UAO_FLAG_KERNSWAP) { 475 KASSERT(kobj_alloced == UAO_FLAG_KERNOBJ); 476 aobj = &kernel_object_store; 477 kobj_alloced = UAO_FLAG_KERNSWAP; 478 refs = 0xdeadbeaf; /* XXX: gcc */ 479 } else { 480 aobj = pool_cache_get(&uvm_aobj_cache, PR_WAITOK); 481 aobj->u_pages = pages; 482 aobj->u_flags = 0; 483 refs = 1; 484 } 485 486 /* 487 * allocate hash/array if necessary 488 * 489 * note: in the KERNSWAP case no need to worry about locking since 490 * we are still booting we should be the only thread around. 491 */ 492 493 if (flags == 0 || (flags & UAO_FLAG_KERNSWAP) != 0) { 494 #if defined(VMSWAP) 495 const int kernswap = (flags & UAO_FLAG_KERNSWAP) != 0; 496 497 /* allocate hash table or array depending on object size */ 498 if (UAO_USES_SWHASH(aobj)) { 499 aobj->u_swhash = hashinit(UAO_SWHASH_BUCKETS(aobj), 500 HASH_LIST, kernswap ? false : true, 501 &aobj->u_swhashmask); 502 if (aobj->u_swhash == NULL) 503 panic("uao_create: hashinit swhash failed"); 504 } else { 505 aobj->u_swslots = kmem_zalloc(pages * sizeof(int), 506 kernswap ? KM_NOSLEEP : KM_SLEEP); 507 if (aobj->u_swslots == NULL) 508 panic("uao_create: malloc swslots failed"); 509 } 510 #endif /* defined(VMSWAP) */ 511 512 if (flags) { 513 aobj->u_flags &= ~UAO_FLAG_NOSWAP; /* clear noswap */ 514 return(&aobj->u_obj); 515 } 516 } 517 518 /* 519 * init aobj fields 520 */ 521 522 UVM_OBJ_INIT(&aobj->u_obj, &aobj_pager, refs); 523 524 /* 525 * now that aobj is ready, add it to the global list 526 */ 527 528 mutex_enter(&uao_list_lock); 529 LIST_INSERT_HEAD(&uao_list, aobj, u_list); 530 mutex_exit(&uao_list_lock); 531 return(&aobj->u_obj); 532 } 533 534 535 536 /* 537 * uao_init: set up aobj pager subsystem 538 * 539 * => called at boot time from uvm_pager_init() 540 */ 541 542 void 543 uao_init(void) 544 { 545 static int uao_initialized; 546 547 if (uao_initialized) 548 return; 549 uao_initialized = true; 550 LIST_INIT(&uao_list); 551 mutex_init(&uao_list_lock, MUTEX_DEFAULT, IPL_NONE); 552 pool_cache_bootstrap(&uvm_aobj_cache, sizeof(struct uvm_aobj), 0, 0, 553 0, "aobj", NULL, IPL_NONE, NULL, NULL, NULL); 554 pool_init(&uao_swhash_elt_pool, sizeof(struct uao_swhash_elt), 555 0, 0, 0, "uaoeltpl", NULL, IPL_VM); 556 } 557 558 /* 559 * uao_reference: add a ref to an aobj 560 * 561 * => aobj must be unlocked 562 * => just lock it and call the locked version 563 */ 564 565 void 566 uao_reference(struct uvm_object *uobj) 567 { 568 569 /* 570 * kernel_object already has plenty of references, leave it alone. 571 */ 572 573 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) 574 return; 575 576 mutex_enter(&uobj->vmobjlock); 577 uao_reference_locked(uobj); 578 mutex_exit(&uobj->vmobjlock); 579 } 580 581 /* 582 * uao_reference_locked: add a ref to an aobj that is already locked 583 * 584 * => aobj must be locked 585 * this needs to be separate from the normal routine 586 * since sometimes we need to add a reference to an aobj when 587 * it's already locked. 588 */ 589 590 static void 591 uao_reference_locked(struct uvm_object *uobj) 592 { 593 UVMHIST_FUNC("uao_reference"); UVMHIST_CALLED(maphist); 594 595 /* 596 * kernel_object already has plenty of references, leave it alone. 597 */ 598 599 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) 600 return; 601 602 uobj->uo_refs++; 603 UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)", 604 uobj, uobj->uo_refs,0,0); 605 } 606 607 /* 608 * uao_detach: drop a reference to an aobj 609 * 610 * => aobj must be unlocked 611 * => just lock it and call the locked version 612 */ 613 614 void 615 uao_detach(struct uvm_object *uobj) 616 { 617 618 /* 619 * detaching from kernel_object is a noop. 620 */ 621 622 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) 623 return; 624 625 mutex_enter(&uobj->vmobjlock); 626 uao_detach_locked(uobj); 627 } 628 629 /* 630 * uao_detach_locked: drop a reference to an aobj 631 * 632 * => aobj must be locked, and is unlocked (or freed) upon return. 633 * this needs to be separate from the normal routine 634 * since sometimes we need to detach from an aobj when 635 * it's already locked. 636 */ 637 638 static void 639 uao_detach_locked(struct uvm_object *uobj) 640 { 641 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 642 struct vm_page *pg; 643 UVMHIST_FUNC("uao_detach"); UVMHIST_CALLED(maphist); 644 645 /* 646 * detaching from kernel_object is a noop. 647 */ 648 649 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) { 650 mutex_exit(&uobj->vmobjlock); 651 return; 652 } 653 654 UVMHIST_LOG(maphist," (uobj=0x%x) ref=%d", uobj,uobj->uo_refs,0,0); 655 uobj->uo_refs--; 656 if (uobj->uo_refs) { 657 mutex_exit(&uobj->vmobjlock); 658 UVMHIST_LOG(maphist, "<- done (rc>0)", 0,0,0,0); 659 return; 660 } 661 662 /* 663 * remove the aobj from the global list. 664 */ 665 666 mutex_enter(&uao_list_lock); 667 LIST_REMOVE(aobj, u_list); 668 mutex_exit(&uao_list_lock); 669 670 /* 671 * free all the pages left in the aobj. for each page, 672 * when the page is no longer busy (and thus after any disk i/o that 673 * it's involved in is complete), release any swap resources and 674 * free the page itself. 675 */ 676 677 mutex_enter(&uvm_pageqlock); 678 while ((pg = TAILQ_FIRST(&uobj->memq)) != NULL) { 679 pmap_page_protect(pg, VM_PROT_NONE); 680 if (pg->flags & PG_BUSY) { 681 pg->flags |= PG_WANTED; 682 mutex_exit(&uvm_pageqlock); 683 UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, false, 684 "uao_det", 0); 685 mutex_enter(&uobj->vmobjlock); 686 mutex_enter(&uvm_pageqlock); 687 continue; 688 } 689 uao_dropswap(&aobj->u_obj, pg->offset >> PAGE_SHIFT); 690 uvm_pagefree(pg); 691 } 692 mutex_exit(&uvm_pageqlock); 693 694 /* 695 * finally, free the aobj itself. 696 */ 697 698 uao_free(aobj); 699 } 700 701 /* 702 * uao_put: flush pages out of a uvm object 703 * 704 * => object should be locked by caller. we may _unlock_ the object 705 * if (and only if) we need to clean a page (PGO_CLEANIT). 706 * XXXJRT Currently, however, we don't. In the case of cleaning 707 * XXXJRT a page, we simply just deactivate it. Should probably 708 * XXXJRT handle this better, in the future (although "flushing" 709 * XXXJRT anonymous memory isn't terribly important). 710 * => if PGO_CLEANIT is not set, then we will neither unlock the object 711 * or block. 712 * => if PGO_ALLPAGE is set, then all pages in the object are valid targets 713 * for flushing. 714 * => NOTE: we rely on the fact that the object's memq is a TAILQ and 715 * that new pages are inserted on the tail end of the list. thus, 716 * we can make a complete pass through the object in one go by starting 717 * at the head and working towards the tail (new pages are put in 718 * front of us). 719 * => NOTE: we are allowed to lock the page queues, so the caller 720 * must not be holding the lock on them [e.g. pagedaemon had 721 * better not call us with the queues locked] 722 * => we return 0 unless we encountered some sort of I/O error 723 * XXXJRT currently never happens, as we never directly initiate 724 * XXXJRT I/O 725 * 726 * note on page traversal: 727 * we can traverse the pages in an object either by going down the 728 * linked list in "uobj->memq", or we can go over the address range 729 * by page doing hash table lookups for each address. depending 730 * on how many pages are in the object it may be cheaper to do one 731 * or the other. we set "by_list" to true if we are using memq. 732 * if the cost of a hash lookup was equal to the cost of the list 733 * traversal we could compare the number of pages in the start->stop 734 * range to the total number of pages in the object. however, it 735 * seems that a hash table lookup is more expensive than the linked 736 * list traversal, so we multiply the number of pages in the 737 * start->stop range by a penalty which we define below. 738 */ 739 740 static int 741 uao_put(struct uvm_object *uobj, voff_t start, voff_t stop, int flags) 742 { 743 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 744 struct vm_page *pg, *nextpg, curmp, endmp; 745 bool by_list; 746 voff_t curoff; 747 UVMHIST_FUNC("uao_put"); UVMHIST_CALLED(maphist); 748 749 KASSERT(mutex_owned(&uobj->vmobjlock)); 750 751 curoff = 0; 752 if (flags & PGO_ALLPAGES) { 753 start = 0; 754 stop = aobj->u_pages << PAGE_SHIFT; 755 by_list = true; /* always go by the list */ 756 } else { 757 start = trunc_page(start); 758 if (stop == 0) { 759 stop = aobj->u_pages << PAGE_SHIFT; 760 } else { 761 stop = round_page(stop); 762 } 763 if (stop > (aobj->u_pages << PAGE_SHIFT)) { 764 printf("uao_flush: strange, got an out of range " 765 "flush (fixed)\n"); 766 stop = aobj->u_pages << PAGE_SHIFT; 767 } 768 by_list = (uobj->uo_npages <= 769 ((stop - start) >> PAGE_SHIFT) * UVM_PAGE_TREE_PENALTY); 770 } 771 UVMHIST_LOG(maphist, 772 " flush start=0x%lx, stop=0x%x, by_list=%d, flags=0x%x", 773 start, stop, by_list, flags); 774 775 /* 776 * Don't need to do any work here if we're not freeing 777 * or deactivating pages. 778 */ 779 780 if ((flags & (PGO_DEACTIVATE|PGO_FREE)) == 0) { 781 mutex_exit(&uobj->vmobjlock); 782 return 0; 783 } 784 785 /* 786 * Initialize the marker pages. See the comment in 787 * genfs_putpages() also. 788 */ 789 790 curmp.uobject = uobj; 791 curmp.offset = (voff_t)-1; 792 curmp.flags = PG_BUSY; 793 endmp.uobject = uobj; 794 endmp.offset = (voff_t)-1; 795 endmp.flags = PG_BUSY; 796 797 /* 798 * now do it. note: we must update nextpg in the body of loop or we 799 * will get stuck. we need to use nextpg if we'll traverse the list 800 * because we may free "pg" before doing the next loop. 801 */ 802 803 if (by_list) { 804 TAILQ_INSERT_TAIL(&uobj->memq, &endmp, listq.queue); 805 nextpg = TAILQ_FIRST(&uobj->memq); 806 } else { 807 curoff = start; 808 nextpg = NULL; /* Quell compiler warning */ 809 } 810 811 /* locked: uobj */ 812 for (;;) { 813 if (by_list) { 814 pg = nextpg; 815 if (pg == &endmp) 816 break; 817 nextpg = TAILQ_NEXT(pg, listq.queue); 818 if (pg->offset < start || pg->offset >= stop) 819 continue; 820 } else { 821 if (curoff < stop) { 822 pg = uvm_pagelookup(uobj, curoff); 823 curoff += PAGE_SIZE; 824 } else 825 break; 826 if (pg == NULL) 827 continue; 828 } 829 830 /* 831 * wait and try again if the page is busy. 832 */ 833 834 if (pg->flags & PG_BUSY) { 835 if (by_list) { 836 TAILQ_INSERT_BEFORE(pg, &curmp, listq.queue); 837 } 838 pg->flags |= PG_WANTED; 839 UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, 0, 840 "uao_put", 0); 841 mutex_enter(&uobj->vmobjlock); 842 if (by_list) { 843 nextpg = TAILQ_NEXT(&curmp, listq.queue); 844 TAILQ_REMOVE(&uobj->memq, &curmp, 845 listq.queue); 846 } else 847 curoff -= PAGE_SIZE; 848 continue; 849 } 850 851 switch (flags & (PGO_CLEANIT|PGO_FREE|PGO_DEACTIVATE)) { 852 853 /* 854 * XXX In these first 3 cases, we always just 855 * XXX deactivate the page. We may want to 856 * XXX handle the different cases more specifically 857 * XXX in the future. 858 */ 859 860 case PGO_CLEANIT|PGO_FREE: 861 case PGO_CLEANIT|PGO_DEACTIVATE: 862 case PGO_DEACTIVATE: 863 deactivate_it: 864 mutex_enter(&uvm_pageqlock); 865 /* skip the page if it's wired */ 866 if (pg->wire_count == 0) { 867 uvm_pagedeactivate(pg); 868 } 869 mutex_exit(&uvm_pageqlock); 870 break; 871 872 case PGO_FREE: 873 /* 874 * If there are multiple references to 875 * the object, just deactivate the page. 876 */ 877 878 if (uobj->uo_refs > 1) 879 goto deactivate_it; 880 881 /* 882 * free the swap slot and the page. 883 */ 884 885 pmap_page_protect(pg, VM_PROT_NONE); 886 887 /* 888 * freeing swapslot here is not strictly necessary. 889 * however, leaving it here doesn't save much 890 * because we need to update swap accounting anyway. 891 */ 892 893 uao_dropswap(uobj, pg->offset >> PAGE_SHIFT); 894 mutex_enter(&uvm_pageqlock); 895 uvm_pagefree(pg); 896 mutex_exit(&uvm_pageqlock); 897 break; 898 899 default: 900 panic("%s: impossible", __func__); 901 } 902 } 903 if (by_list) { 904 TAILQ_REMOVE(&uobj->memq, &endmp, listq.queue); 905 } 906 mutex_exit(&uobj->vmobjlock); 907 return 0; 908 } 909 910 /* 911 * uao_get: fetch me a page 912 * 913 * we have three cases: 914 * 1: page is resident -> just return the page. 915 * 2: page is zero-fill -> allocate a new page and zero it. 916 * 3: page is swapped out -> fetch the page from swap. 917 * 918 * cases 1 and 2 can be handled with PGO_LOCKED, case 3 cannot. 919 * so, if the "center" page hits case 3 (or any page, with PGO_ALLPAGES), 920 * then we will need to return EBUSY. 921 * 922 * => prefer map unlocked (not required) 923 * => object must be locked! we will _unlock_ it before starting any I/O. 924 * => flags: PGO_ALLPAGES: get all of the pages 925 * PGO_LOCKED: fault data structures are locked 926 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 927 * => NOTE: caller must check for released pages!! 928 */ 929 930 static int 931 uao_get(struct uvm_object *uobj, voff_t offset, struct vm_page **pps, 932 int *npagesp, int centeridx, vm_prot_t access_type, int advice, int flags) 933 { 934 #if defined(VMSWAP) 935 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 936 #endif /* defined(VMSWAP) */ 937 voff_t current_offset; 938 struct vm_page *ptmp = NULL; /* Quell compiler warning */ 939 int lcv, gotpages, maxpages, swslot, pageidx; 940 bool done; 941 UVMHIST_FUNC("uao_get"); UVMHIST_CALLED(pdhist); 942 943 UVMHIST_LOG(pdhist, "aobj=%p offset=%d, flags=%d", 944 (struct uvm_aobj *)uobj, offset, flags,0); 945 946 /* 947 * get number of pages 948 */ 949 950 maxpages = *npagesp; 951 952 /* 953 * step 1: handled the case where fault data structures are locked. 954 */ 955 956 if (flags & PGO_LOCKED) { 957 958 /* 959 * step 1a: get pages that are already resident. only do 960 * this if the data structures are locked (i.e. the first 961 * time through). 962 */ 963 964 done = true; /* be optimistic */ 965 gotpages = 0; /* # of pages we got so far */ 966 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 967 lcv++, current_offset += PAGE_SIZE) { 968 /* do we care about this page? if not, skip it */ 969 if (pps[lcv] == PGO_DONTCARE) 970 continue; 971 ptmp = uvm_pagelookup(uobj, current_offset); 972 973 /* 974 * if page is new, attempt to allocate the page, 975 * zero-fill'd. 976 */ 977 978 if (ptmp == NULL && uao_find_swslot(&aobj->u_obj, 979 current_offset >> PAGE_SHIFT) == 0) { 980 ptmp = uvm_pagealloc(uobj, current_offset, 981 NULL, UVM_PGA_ZERO); 982 if (ptmp) { 983 /* new page */ 984 ptmp->flags &= ~(PG_FAKE); 985 ptmp->pqflags |= PQ_AOBJ; 986 goto gotpage; 987 } 988 } 989 990 /* 991 * to be useful must get a non-busy page 992 */ 993 994 if (ptmp == NULL || (ptmp->flags & PG_BUSY) != 0) { 995 if (lcv == centeridx || 996 (flags & PGO_ALLPAGES) != 0) 997 /* need to do a wait or I/O! */ 998 done = false; 999 continue; 1000 } 1001 1002 /* 1003 * useful page: busy/lock it and plug it in our 1004 * result array 1005 */ 1006 1007 /* caller must un-busy this page */ 1008 ptmp->flags |= PG_BUSY; 1009 UVM_PAGE_OWN(ptmp, "uao_get1"); 1010 gotpage: 1011 pps[lcv] = ptmp; 1012 gotpages++; 1013 } 1014 1015 /* 1016 * step 1b: now we've either done everything needed or we 1017 * to unlock and do some waiting or I/O. 1018 */ 1019 1020 UVMHIST_LOG(pdhist, "<- done (done=%d)", done, 0,0,0); 1021 *npagesp = gotpages; 1022 if (done) 1023 return 0; 1024 else 1025 return EBUSY; 1026 } 1027 1028 /* 1029 * step 2: get non-resident or busy pages. 1030 * object is locked. data structures are unlocked. 1031 */ 1032 1033 if ((flags & PGO_SYNCIO) == 0) { 1034 goto done; 1035 } 1036 1037 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 1038 lcv++, current_offset += PAGE_SIZE) { 1039 1040 /* 1041 * - skip over pages we've already gotten or don't want 1042 * - skip over pages we don't _have_ to get 1043 */ 1044 1045 if (pps[lcv] != NULL || 1046 (lcv != centeridx && (flags & PGO_ALLPAGES) == 0)) 1047 continue; 1048 1049 pageidx = current_offset >> PAGE_SHIFT; 1050 1051 /* 1052 * we have yet to locate the current page (pps[lcv]). we 1053 * first look for a page that is already at the current offset. 1054 * if we find a page, we check to see if it is busy or 1055 * released. if that is the case, then we sleep on the page 1056 * until it is no longer busy or released and repeat the lookup. 1057 * if the page we found is neither busy nor released, then we 1058 * busy it (so we own it) and plug it into pps[lcv]. this 1059 * 'break's the following while loop and indicates we are 1060 * ready to move on to the next page in the "lcv" loop above. 1061 * 1062 * if we exit the while loop with pps[lcv] still set to NULL, 1063 * then it means that we allocated a new busy/fake/clean page 1064 * ptmp in the object and we need to do I/O to fill in the data. 1065 */ 1066 1067 /* top of "pps" while loop */ 1068 while (pps[lcv] == NULL) { 1069 /* look for a resident page */ 1070 ptmp = uvm_pagelookup(uobj, current_offset); 1071 1072 /* not resident? allocate one now (if we can) */ 1073 if (ptmp == NULL) { 1074 1075 ptmp = uvm_pagealloc(uobj, current_offset, 1076 NULL, 0); 1077 1078 /* out of RAM? */ 1079 if (ptmp == NULL) { 1080 mutex_exit(&uobj->vmobjlock); 1081 UVMHIST_LOG(pdhist, 1082 "sleeping, ptmp == NULL\n",0,0,0,0); 1083 uvm_wait("uao_getpage"); 1084 mutex_enter(&uobj->vmobjlock); 1085 continue; 1086 } 1087 1088 /* 1089 * safe with PQ's unlocked: because we just 1090 * alloc'd the page 1091 */ 1092 1093 ptmp->pqflags |= PQ_AOBJ; 1094 1095 /* 1096 * got new page ready for I/O. break pps while 1097 * loop. pps[lcv] is still NULL. 1098 */ 1099 1100 break; 1101 } 1102 1103 /* page is there, see if we need to wait on it */ 1104 if ((ptmp->flags & PG_BUSY) != 0) { 1105 ptmp->flags |= PG_WANTED; 1106 UVMHIST_LOG(pdhist, 1107 "sleeping, ptmp->flags 0x%x\n", 1108 ptmp->flags,0,0,0); 1109 UVM_UNLOCK_AND_WAIT(ptmp, &uobj->vmobjlock, 1110 false, "uao_get", 0); 1111 mutex_enter(&uobj->vmobjlock); 1112 continue; 1113 } 1114 1115 /* 1116 * if we get here then the page has become resident and 1117 * unbusy between steps 1 and 2. we busy it now (so we 1118 * own it) and set pps[lcv] (so that we exit the while 1119 * loop). 1120 */ 1121 1122 /* we own it, caller must un-busy */ 1123 ptmp->flags |= PG_BUSY; 1124 UVM_PAGE_OWN(ptmp, "uao_get2"); 1125 pps[lcv] = ptmp; 1126 } 1127 1128 /* 1129 * if we own the valid page at the correct offset, pps[lcv] will 1130 * point to it. nothing more to do except go to the next page. 1131 */ 1132 1133 if (pps[lcv]) 1134 continue; /* next lcv */ 1135 1136 /* 1137 * we have a "fake/busy/clean" page that we just allocated. 1138 * do the needed "i/o", either reading from swap or zeroing. 1139 */ 1140 1141 swslot = uao_find_swslot(&aobj->u_obj, pageidx); 1142 1143 /* 1144 * just zero the page if there's nothing in swap. 1145 */ 1146 1147 if (swslot == 0) { 1148 1149 /* 1150 * page hasn't existed before, just zero it. 1151 */ 1152 1153 uvm_pagezero(ptmp); 1154 } else { 1155 #if defined(VMSWAP) 1156 int error; 1157 1158 UVMHIST_LOG(pdhist, "pagein from swslot %d", 1159 swslot, 0,0,0); 1160 1161 /* 1162 * page in the swapped-out page. 1163 * unlock object for i/o, relock when done. 1164 */ 1165 1166 mutex_exit(&uobj->vmobjlock); 1167 error = uvm_swap_get(ptmp, swslot, PGO_SYNCIO); 1168 mutex_enter(&uobj->vmobjlock); 1169 1170 /* 1171 * I/O done. check for errors. 1172 */ 1173 1174 if (error != 0) { 1175 UVMHIST_LOG(pdhist, "<- done (error=%d)", 1176 error,0,0,0); 1177 if (ptmp->flags & PG_WANTED) 1178 wakeup(ptmp); 1179 1180 /* 1181 * remove the swap slot from the aobj 1182 * and mark the aobj as having no real slot. 1183 * don't free the swap slot, thus preventing 1184 * it from being used again. 1185 */ 1186 1187 swslot = uao_set_swslot(&aobj->u_obj, pageidx, 1188 SWSLOT_BAD); 1189 if (swslot > 0) { 1190 uvm_swap_markbad(swslot, 1); 1191 } 1192 1193 mutex_enter(&uvm_pageqlock); 1194 uvm_pagefree(ptmp); 1195 mutex_exit(&uvm_pageqlock); 1196 mutex_exit(&uobj->vmobjlock); 1197 return error; 1198 } 1199 #else /* defined(VMSWAP) */ 1200 panic("%s: pagein", __func__); 1201 #endif /* defined(VMSWAP) */ 1202 } 1203 1204 if ((access_type & VM_PROT_WRITE) == 0) { 1205 ptmp->flags |= PG_CLEAN; 1206 pmap_clear_modify(ptmp); 1207 } 1208 1209 /* 1210 * we got the page! clear the fake flag (indicates valid 1211 * data now in page) and plug into our result array. note 1212 * that page is still busy. 1213 * 1214 * it is the callers job to: 1215 * => check if the page is released 1216 * => unbusy the page 1217 * => activate the page 1218 */ 1219 1220 ptmp->flags &= ~PG_FAKE; 1221 pps[lcv] = ptmp; 1222 } 1223 1224 /* 1225 * finally, unlock object and return. 1226 */ 1227 1228 done: 1229 mutex_exit(&uobj->vmobjlock); 1230 UVMHIST_LOG(pdhist, "<- done (OK)",0,0,0,0); 1231 return 0; 1232 } 1233 1234 #if defined(VMSWAP) 1235 1236 /* 1237 * uao_dropswap: release any swap resources from this aobj page. 1238 * 1239 * => aobj must be locked or have a reference count of 0. 1240 */ 1241 1242 void 1243 uao_dropswap(struct uvm_object *uobj, int pageidx) 1244 { 1245 int slot; 1246 1247 slot = uao_set_swslot(uobj, pageidx, 0); 1248 if (slot) { 1249 uvm_swap_free(slot, 1); 1250 } 1251 } 1252 1253 /* 1254 * page in every page in every aobj that is paged-out to a range of swslots. 1255 * 1256 * => nothing should be locked. 1257 * => returns true if pagein was aborted due to lack of memory. 1258 */ 1259 1260 bool 1261 uao_swap_off(int startslot, int endslot) 1262 { 1263 struct uvm_aobj *aobj, *nextaobj; 1264 bool rv; 1265 1266 /* 1267 * walk the list of all aobjs. 1268 */ 1269 1270 restart: 1271 mutex_enter(&uao_list_lock); 1272 for (aobj = LIST_FIRST(&uao_list); 1273 aobj != NULL; 1274 aobj = nextaobj) { 1275 1276 /* 1277 * try to get the object lock, start all over if we fail. 1278 * most of the time we'll get the aobj lock, 1279 * so this should be a rare case. 1280 */ 1281 1282 if (!mutex_tryenter(&aobj->u_obj.vmobjlock)) { 1283 mutex_exit(&uao_list_lock); 1284 /* XXX Better than yielding but inadequate. */ 1285 kpause("livelock", false, 1, NULL); 1286 goto restart; 1287 } 1288 1289 /* 1290 * add a ref to the aobj so it doesn't disappear 1291 * while we're working. 1292 */ 1293 1294 uao_reference_locked(&aobj->u_obj); 1295 1296 /* 1297 * now it's safe to unlock the uao list. 1298 */ 1299 1300 mutex_exit(&uao_list_lock); 1301 1302 /* 1303 * page in any pages in the swslot range. 1304 * if there's an error, abort and return the error. 1305 */ 1306 1307 rv = uao_pagein(aobj, startslot, endslot); 1308 if (rv) { 1309 uao_detach_locked(&aobj->u_obj); 1310 return rv; 1311 } 1312 1313 /* 1314 * we're done with this aobj. 1315 * relock the list and drop our ref on the aobj. 1316 */ 1317 1318 mutex_enter(&uao_list_lock); 1319 nextaobj = LIST_NEXT(aobj, u_list); 1320 uao_detach_locked(&aobj->u_obj); 1321 } 1322 1323 /* 1324 * done with traversal, unlock the list 1325 */ 1326 mutex_exit(&uao_list_lock); 1327 return false; 1328 } 1329 1330 1331 /* 1332 * page in any pages from aobj in the given range. 1333 * 1334 * => aobj must be locked and is returned locked. 1335 * => returns true if pagein was aborted due to lack of memory. 1336 */ 1337 static bool 1338 uao_pagein(struct uvm_aobj *aobj, int startslot, int endslot) 1339 { 1340 bool rv; 1341 1342 if (UAO_USES_SWHASH(aobj)) { 1343 struct uao_swhash_elt *elt; 1344 int buck; 1345 1346 restart: 1347 for (buck = aobj->u_swhashmask; buck >= 0; buck--) { 1348 for (elt = LIST_FIRST(&aobj->u_swhash[buck]); 1349 elt != NULL; 1350 elt = LIST_NEXT(elt, list)) { 1351 int i; 1352 1353 for (i = 0; i < UAO_SWHASH_CLUSTER_SIZE; i++) { 1354 int slot = elt->slots[i]; 1355 1356 /* 1357 * if the slot isn't in range, skip it. 1358 */ 1359 1360 if (slot < startslot || 1361 slot >= endslot) { 1362 continue; 1363 } 1364 1365 /* 1366 * process the page, 1367 * the start over on this object 1368 * since the swhash elt 1369 * may have been freed. 1370 */ 1371 1372 rv = uao_pagein_page(aobj, 1373 UAO_SWHASH_ELT_PAGEIDX_BASE(elt) + i); 1374 if (rv) { 1375 return rv; 1376 } 1377 goto restart; 1378 } 1379 } 1380 } 1381 } else { 1382 int i; 1383 1384 for (i = 0; i < aobj->u_pages; i++) { 1385 int slot = aobj->u_swslots[i]; 1386 1387 /* 1388 * if the slot isn't in range, skip it 1389 */ 1390 1391 if (slot < startslot || slot >= endslot) { 1392 continue; 1393 } 1394 1395 /* 1396 * process the page. 1397 */ 1398 1399 rv = uao_pagein_page(aobj, i); 1400 if (rv) { 1401 return rv; 1402 } 1403 } 1404 } 1405 1406 return false; 1407 } 1408 1409 /* 1410 * page in a page from an aobj. used for swap_off. 1411 * returns true if pagein was aborted due to lack of memory. 1412 * 1413 * => aobj must be locked and is returned locked. 1414 */ 1415 1416 static bool 1417 uao_pagein_page(struct uvm_aobj *aobj, int pageidx) 1418 { 1419 struct vm_page *pg; 1420 int rv, npages; 1421 1422 pg = NULL; 1423 npages = 1; 1424 /* locked: aobj */ 1425 rv = uao_get(&aobj->u_obj, pageidx << PAGE_SHIFT, 1426 &pg, &npages, 0, VM_PROT_READ|VM_PROT_WRITE, 0, PGO_SYNCIO); 1427 /* unlocked: aobj */ 1428 1429 /* 1430 * relock and finish up. 1431 */ 1432 1433 mutex_enter(&aobj->u_obj.vmobjlock); 1434 switch (rv) { 1435 case 0: 1436 break; 1437 1438 case EIO: 1439 case ERESTART: 1440 1441 /* 1442 * nothing more to do on errors. 1443 * ERESTART can only mean that the anon was freed, 1444 * so again there's nothing to do. 1445 */ 1446 1447 return false; 1448 1449 default: 1450 return true; 1451 } 1452 1453 /* 1454 * ok, we've got the page now. 1455 * mark it as dirty, clear its swslot and un-busy it. 1456 */ 1457 uao_dropswap(&aobj->u_obj, pageidx); 1458 1459 /* 1460 * make sure it's on a page queue. 1461 */ 1462 mutex_enter(&uvm_pageqlock); 1463 if (pg->wire_count == 0) 1464 uvm_pageenqueue(pg); 1465 mutex_exit(&uvm_pageqlock); 1466 1467 if (pg->flags & PG_WANTED) { 1468 wakeup(pg); 1469 } 1470 pg->flags &= ~(PG_WANTED|PG_BUSY|PG_CLEAN|PG_FAKE); 1471 UVM_PAGE_OWN(pg, NULL); 1472 1473 return false; 1474 } 1475 1476 /* 1477 * uao_dropswap_range: drop swapslots in the range. 1478 * 1479 * => aobj must be locked and is returned locked. 1480 * => start is inclusive. end is exclusive. 1481 */ 1482 1483 void 1484 uao_dropswap_range(struct uvm_object *uobj, voff_t start, voff_t end) 1485 { 1486 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 1487 1488 KASSERT(mutex_owned(&uobj->vmobjlock)); 1489 1490 uao_dropswap_range1(aobj, start, end); 1491 } 1492 1493 static void 1494 uao_dropswap_range1(struct uvm_aobj *aobj, voff_t start, voff_t end) 1495 { 1496 int swpgonlydelta = 0; 1497 1498 if (end == 0) { 1499 end = INT64_MAX; 1500 } 1501 1502 if (UAO_USES_SWHASH(aobj)) { 1503 int i, hashbuckets = aobj->u_swhashmask + 1; 1504 voff_t taghi; 1505 voff_t taglo; 1506 1507 taglo = UAO_SWHASH_ELT_TAG(start); 1508 taghi = UAO_SWHASH_ELT_TAG(end); 1509 1510 for (i = 0; i < hashbuckets; i++) { 1511 struct uao_swhash_elt *elt, *next; 1512 1513 for (elt = LIST_FIRST(&aobj->u_swhash[i]); 1514 elt != NULL; 1515 elt = next) { 1516 int startidx, endidx; 1517 int j; 1518 1519 next = LIST_NEXT(elt, list); 1520 1521 if (elt->tag < taglo || taghi < elt->tag) { 1522 continue; 1523 } 1524 1525 if (elt->tag == taglo) { 1526 startidx = 1527 UAO_SWHASH_ELT_PAGESLOT_IDX(start); 1528 } else { 1529 startidx = 0; 1530 } 1531 1532 if (elt->tag == taghi) { 1533 endidx = 1534 UAO_SWHASH_ELT_PAGESLOT_IDX(end); 1535 } else { 1536 endidx = UAO_SWHASH_CLUSTER_SIZE; 1537 } 1538 1539 for (j = startidx; j < endidx; j++) { 1540 int slot = elt->slots[j]; 1541 1542 KASSERT(uvm_pagelookup(&aobj->u_obj, 1543 (UAO_SWHASH_ELT_PAGEIDX_BASE(elt) 1544 + j) << PAGE_SHIFT) == NULL); 1545 if (slot > 0) { 1546 uvm_swap_free(slot, 1); 1547 swpgonlydelta++; 1548 KASSERT(elt->count > 0); 1549 elt->slots[j] = 0; 1550 elt->count--; 1551 } 1552 } 1553 1554 if (elt->count == 0) { 1555 LIST_REMOVE(elt, list); 1556 pool_put(&uao_swhash_elt_pool, elt); 1557 } 1558 } 1559 } 1560 } else { 1561 int i; 1562 1563 if (aobj->u_pages < end) { 1564 end = aobj->u_pages; 1565 } 1566 for (i = start; i < end; i++) { 1567 int slot = aobj->u_swslots[i]; 1568 1569 if (slot > 0) { 1570 uvm_swap_free(slot, 1); 1571 swpgonlydelta++; 1572 } 1573 } 1574 } 1575 1576 /* 1577 * adjust the counter of pages only in swap for all 1578 * the swap slots we've freed. 1579 */ 1580 1581 if (swpgonlydelta > 0) { 1582 mutex_enter(&uvm_swap_data_lock); 1583 KASSERT(uvmexp.swpgonly >= swpgonlydelta); 1584 uvmexp.swpgonly -= swpgonlydelta; 1585 mutex_exit(&uvm_swap_data_lock); 1586 } 1587 } 1588 1589 #endif /* defined(VMSWAP) */ 1590