1 /* $NetBSD: uvm_aobj.c,v 1.37 2000/11/25 06:27:59 chs 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 46 47 #include "opt_uvmhist.h" 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/proc.h> 52 #include <sys/malloc.h> 53 #include <sys/kernel.h> 54 #include <sys/pool.h> 55 #include <sys/kernel.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 /* given an ELT and a page index, find the swap slot */ 85 #define UAO_SWHASH_ELT_PAGESLOT(ELT, PAGEIDX) \ 86 ((ELT)->slots[(PAGEIDX) & (UAO_SWHASH_CLUSTER_SIZE - 1)]) 87 88 /* given an ELT, return its pageidx base */ 89 #define UAO_SWHASH_ELT_PAGEIDX_BASE(ELT) \ 90 ((ELT)->tag << UAO_SWHASH_CLUSTER_SHIFT) 91 92 /* 93 * the swhash hash function 94 */ 95 #define UAO_SWHASH_HASH(AOBJ, PAGEIDX) \ 96 (&(AOBJ)->u_swhash[(((PAGEIDX) >> UAO_SWHASH_CLUSTER_SHIFT) \ 97 & (AOBJ)->u_swhashmask)]) 98 99 /* 100 * the swhash threshhold determines if we will use an array or a 101 * hash table to store the list of allocated swap blocks. 102 */ 103 104 #define UAO_SWHASH_THRESHOLD (UAO_SWHASH_CLUSTER_SIZE * 4) 105 #define UAO_USES_SWHASH(AOBJ) \ 106 ((AOBJ)->u_pages > UAO_SWHASH_THRESHOLD) /* use hash? */ 107 108 /* 109 * the number of buckets in a swhash, with an upper bound 110 */ 111 #define UAO_SWHASH_MAXBUCKETS 256 112 #define UAO_SWHASH_BUCKETS(AOBJ) \ 113 (min((AOBJ)->u_pages >> UAO_SWHASH_CLUSTER_SHIFT, \ 114 UAO_SWHASH_MAXBUCKETS)) 115 116 117 /* 118 * uao_swhash_elt: when a hash table is being used, this structure defines 119 * the format of an entry in the bucket list. 120 */ 121 122 struct uao_swhash_elt { 123 LIST_ENTRY(uao_swhash_elt) list; /* the hash list */ 124 voff_t tag; /* our 'tag' */ 125 int count; /* our number of active slots */ 126 int slots[UAO_SWHASH_CLUSTER_SIZE]; /* the slots */ 127 }; 128 129 /* 130 * uao_swhash: the swap hash table structure 131 */ 132 133 LIST_HEAD(uao_swhash, uao_swhash_elt); 134 135 /* 136 * uao_swhash_elt_pool: pool of uao_swhash_elt structures 137 */ 138 139 struct pool uao_swhash_elt_pool; 140 141 /* 142 * uvm_aobj: the actual anon-backed uvm_object 143 * 144 * => the uvm_object is at the top of the structure, this allows 145 * (struct uvm_device *) == (struct uvm_object *) 146 * => only one of u_swslots and u_swhash is used in any given aobj 147 */ 148 149 struct uvm_aobj { 150 struct uvm_object u_obj; /* has: lock, pgops, memq, #pages, #refs */ 151 int u_pages; /* number of pages in entire object */ 152 int u_flags; /* the flags (see uvm_aobj.h) */ 153 int *u_swslots; /* array of offset->swapslot mappings */ 154 /* 155 * hashtable of offset->swapslot mappings 156 * (u_swhash is an array of bucket heads) 157 */ 158 struct uao_swhash *u_swhash; 159 u_long u_swhashmask; /* mask for hashtable */ 160 LIST_ENTRY(uvm_aobj) u_list; /* global list of aobjs */ 161 }; 162 163 /* 164 * uvm_aobj_pool: pool of uvm_aobj structures 165 */ 166 167 struct pool uvm_aobj_pool; 168 169 /* 170 * local functions 171 */ 172 173 static struct uao_swhash_elt *uao_find_swhash_elt __P((struct uvm_aobj *, 174 int, boolean_t)); 175 static int uao_find_swslot __P((struct uvm_aobj *, int)); 176 static boolean_t uao_flush __P((struct uvm_object *, 177 voff_t, voff_t, int)); 178 static void uao_free __P((struct uvm_aobj *)); 179 static int uao_get __P((struct uvm_object *, voff_t, 180 vm_page_t *, int *, int, 181 vm_prot_t, int, int)); 182 static boolean_t uao_releasepg __P((struct vm_page *, 183 struct vm_page **)); 184 static boolean_t uao_pagein __P((struct uvm_aobj *, int, int)); 185 static boolean_t uao_pagein_page __P((struct uvm_aobj *, int)); 186 187 /* 188 * aobj_pager 189 * 190 * note that some functions (e.g. put) are handled elsewhere 191 */ 192 193 struct uvm_pagerops aobj_pager = { 194 NULL, /* init */ 195 uao_reference, /* reference */ 196 uao_detach, /* detach */ 197 NULL, /* fault */ 198 uao_flush, /* flush */ 199 uao_get, /* get */ 200 NULL, /* put (done by pagedaemon) */ 201 NULL, /* cluster */ 202 NULL, /* mk_pcluster */ 203 uao_releasepg /* releasepg */ 204 }; 205 206 /* 207 * uao_list: global list of active aobjs, locked by uao_list_lock 208 */ 209 210 static LIST_HEAD(aobjlist, uvm_aobj) uao_list; 211 static simple_lock_data_t uao_list_lock; 212 213 214 /* 215 * functions 216 */ 217 218 /* 219 * hash table/array related functions 220 */ 221 222 /* 223 * uao_find_swhash_elt: find (or create) a hash table entry for a page 224 * offset. 225 * 226 * => the object should be locked by the caller 227 */ 228 229 static struct uao_swhash_elt * 230 uao_find_swhash_elt(aobj, pageidx, create) 231 struct uvm_aobj *aobj; 232 int pageidx; 233 boolean_t 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); /* first hash to get bucket */ 240 page_tag = UAO_SWHASH_ELT_TAG(pageidx); /* tag to search for */ 241 242 /* 243 * now search the bucket for the requested tag 244 */ 245 LIST_FOREACH(elt, swhash, list) { 246 if (elt->tag == page_tag) 247 return(elt); 248 } 249 250 /* fail now if we are not allowed to create a new entry in the bucket */ 251 if (!create) 252 return NULL; 253 254 255 /* 256 * allocate a new entry for the bucket and init/insert it in 257 */ 258 elt = pool_get(&uao_swhash_elt_pool, PR_WAITOK); 259 LIST_INSERT_HEAD(swhash, elt, list); 260 elt->tag = page_tag; 261 elt->count = 0; 262 memset(elt->slots, 0, sizeof(elt->slots)); 263 264 return(elt); 265 } 266 267 /* 268 * uao_find_swslot: find the swap slot number for an aobj/pageidx 269 * 270 * => object must be locked by caller 271 */ 272 __inline static int 273 uao_find_swslot(aobj, pageidx) 274 struct uvm_aobj *aobj; 275 int pageidx; 276 { 277 278 /* 279 * if noswap flag is set, then we never return a slot 280 */ 281 282 if (aobj->u_flags & UAO_FLAG_NOSWAP) 283 return(0); 284 285 /* 286 * if hashing, look in hash table. 287 */ 288 289 if (UAO_USES_SWHASH(aobj)) { 290 struct uao_swhash_elt *elt = 291 uao_find_swhash_elt(aobj, pageidx, FALSE); 292 293 if (elt) 294 return(UAO_SWHASH_ELT_PAGESLOT(elt, pageidx)); 295 else 296 return(0); 297 } 298 299 /* 300 * otherwise, look in the array 301 */ 302 return(aobj->u_swslots[pageidx]); 303 } 304 305 /* 306 * uao_set_swslot: set the swap slot for a page in an aobj. 307 * 308 * => setting a slot to zero frees the slot 309 * => object must be locked by caller 310 */ 311 int 312 uao_set_swslot(uobj, pageidx, slot) 313 struct uvm_object *uobj; 314 int pageidx, slot; 315 { 316 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 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 slot 324 */ 325 326 if (aobj->u_flags & UAO_FLAG_NOSWAP) { 327 328 if (slot == 0) 329 return(0); /* a clear is ok */ 330 331 /* but a set is not */ 332 printf("uao_set_swslot: uobj = %p\n", uobj); 333 panic("uao_set_swslot: attempt to set a slot on a NOSWAP object"); 334 } 335 336 /* 337 * are we using a hash table? if so, add it in the hash. 338 */ 339 340 if (UAO_USES_SWHASH(aobj)) { 341 /* 342 * Avoid allocating an entry just to free it again if 343 * the page had not swap slot in the first place, and 344 * we are freeing. 345 */ 346 struct uao_swhash_elt *elt = 347 uao_find_swhash_elt(aobj, pageidx, slot ? TRUE : FALSE); 348 if (elt == NULL) { 349 #ifdef DIAGNOSTIC 350 if (slot) 351 panic("uao_set_swslot: didn't create elt"); 352 #endif 353 return (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 /* an allocation? */ 365 if (slot) { 366 if (oldslot == 0) 367 elt->count++; 368 } else { /* freeing slot ... */ 369 if (oldslot) /* to be safe */ 370 elt->count--; 371 372 if (elt->count == 0) { 373 LIST_REMOVE(elt, list); 374 pool_put(&uao_swhash_elt_pool, elt); 375 } 376 } 377 } else { 378 /* we are using an array */ 379 oldslot = aobj->u_swslots[pageidx]; 380 aobj->u_swslots[pageidx] = slot; 381 } 382 return (oldslot); 383 } 384 385 /* 386 * end of hash/array functions 387 */ 388 389 /* 390 * uao_free: free all resources held by an aobj, and then free the aobj 391 * 392 * => the aobj should be dead 393 */ 394 static void 395 uao_free(aobj) 396 struct uvm_aobj *aobj; 397 { 398 399 simple_unlock(&aobj->u_obj.vmobjlock); 400 401 if (UAO_USES_SWHASH(aobj)) { 402 int i, hashbuckets = aobj->u_swhashmask + 1; 403 404 /* 405 * free the swslots from each hash bucket, 406 * then the hash bucket, and finally the hash table itself. 407 */ 408 for (i = 0; i < hashbuckets; i++) { 409 struct uao_swhash_elt *elt, *next; 410 411 for (elt = LIST_FIRST(&aobj->u_swhash[i]); 412 elt != NULL; 413 elt = next) { 414 int j; 415 416 for (j = 0; j < UAO_SWHASH_CLUSTER_SIZE; j++) { 417 int slot = elt->slots[j]; 418 419 if (slot == 0) { 420 continue; 421 } 422 uvm_swap_free(slot, 1); 423 424 /* 425 * this page is no longer 426 * only in swap. 427 */ 428 simple_lock(&uvm.swap_data_lock); 429 uvmexp.swpgonly--; 430 simple_unlock(&uvm.swap_data_lock); 431 } 432 433 next = LIST_NEXT(elt, list); 434 pool_put(&uao_swhash_elt_pool, elt); 435 } 436 } 437 free(aobj->u_swhash, M_UVMAOBJ); 438 } else { 439 int i; 440 441 /* 442 * free the array 443 */ 444 445 for (i = 0; i < aobj->u_pages; i++) { 446 int slot = aobj->u_swslots[i]; 447 448 if (slot) { 449 uvm_swap_free(slot, 1); 450 451 /* this page is no longer only in swap. */ 452 simple_lock(&uvm.swap_data_lock); 453 uvmexp.swpgonly--; 454 simple_unlock(&uvm.swap_data_lock); 455 } 456 } 457 free(aobj->u_swslots, M_UVMAOBJ); 458 } 459 460 /* 461 * finally free the aobj itself 462 */ 463 pool_put(&uvm_aobj_pool, aobj); 464 } 465 466 /* 467 * pager functions 468 */ 469 470 /* 471 * uao_create: create an aobj of the given size and return its uvm_object. 472 * 473 * => for normal use, flags are always zero 474 * => for the kernel object, the flags are: 475 * UAO_FLAG_KERNOBJ - allocate the kernel object (can only happen once) 476 * UAO_FLAG_KERNSWAP - enable swapping of kernel object (" ") 477 */ 478 struct uvm_object * 479 uao_create(size, flags) 480 vsize_t size; 481 int flags; 482 { 483 static struct uvm_aobj kernel_object_store; /* home of kernel_object */ 484 static int kobj_alloced = 0; /* not allocated yet */ 485 int pages = round_page(size) >> PAGE_SHIFT; 486 struct uvm_aobj *aobj; 487 488 /* 489 * malloc a new aobj unless we are asked for the kernel object 490 */ 491 if (flags & UAO_FLAG_KERNOBJ) { /* want kernel object? */ 492 if (kobj_alloced) 493 panic("uao_create: kernel object already allocated"); 494 495 aobj = &kernel_object_store; 496 aobj->u_pages = pages; 497 aobj->u_flags = UAO_FLAG_NOSWAP; /* no swap to start */ 498 /* we are special, we never die */ 499 aobj->u_obj.uo_refs = UVM_OBJ_KERN; 500 kobj_alloced = UAO_FLAG_KERNOBJ; 501 } else if (flags & UAO_FLAG_KERNSWAP) { 502 aobj = &kernel_object_store; 503 if (kobj_alloced != UAO_FLAG_KERNOBJ) 504 panic("uao_create: asked to enable swap on kernel object"); 505 kobj_alloced = UAO_FLAG_KERNSWAP; 506 } else { /* normal object */ 507 aobj = pool_get(&uvm_aobj_pool, PR_WAITOK); 508 aobj->u_pages = pages; 509 aobj->u_flags = 0; /* normal object */ 510 aobj->u_obj.uo_refs = 1; /* start with 1 reference */ 511 } 512 513 /* 514 * allocate hash/array if necessary 515 * 516 * note: in the KERNSWAP case no need to worry about locking since 517 * we are still booting we should be the only thread around. 518 */ 519 if (flags == 0 || (flags & UAO_FLAG_KERNSWAP) != 0) { 520 int mflags = (flags & UAO_FLAG_KERNSWAP) != 0 ? 521 M_NOWAIT : M_WAITOK; 522 523 /* allocate hash table or array depending on object size */ 524 if (UAO_USES_SWHASH(aobj)) { 525 aobj->u_swhash = hashinit(UAO_SWHASH_BUCKETS(aobj), 526 HASH_LIST, M_UVMAOBJ, mflags, &aobj->u_swhashmask); 527 if (aobj->u_swhash == NULL) 528 panic("uao_create: hashinit swhash failed"); 529 } else { 530 aobj->u_swslots = malloc(pages * sizeof(int), 531 M_UVMAOBJ, mflags); 532 if (aobj->u_swslots == NULL) 533 panic("uao_create: malloc swslots failed"); 534 memset(aobj->u_swslots, 0, pages * sizeof(int)); 535 } 536 537 if (flags) { 538 aobj->u_flags &= ~UAO_FLAG_NOSWAP; /* clear noswap */ 539 return(&aobj->u_obj); 540 /* done! */ 541 } 542 } 543 544 /* 545 * init aobj fields 546 */ 547 simple_lock_init(&aobj->u_obj.vmobjlock); 548 aobj->u_obj.pgops = &aobj_pager; 549 TAILQ_INIT(&aobj->u_obj.memq); 550 aobj->u_obj.uo_npages = 0; 551 552 /* 553 * now that aobj is ready, add it to the global list 554 */ 555 simple_lock(&uao_list_lock); 556 LIST_INSERT_HEAD(&uao_list, aobj, u_list); 557 simple_unlock(&uao_list_lock); 558 559 /* 560 * done! 561 */ 562 return(&aobj->u_obj); 563 } 564 565 566 567 /* 568 * uao_init: set up aobj pager subsystem 569 * 570 * => called at boot time from uvm_pager_init() 571 */ 572 void 573 uao_init() 574 { 575 static int uao_initialized; 576 577 if (uao_initialized) 578 return; 579 uao_initialized = TRUE; 580 581 LIST_INIT(&uao_list); 582 simple_lock_init(&uao_list_lock); 583 584 /* 585 * NOTE: Pages fror this pool must not come from a pageable 586 * kernel map! 587 */ 588 pool_init(&uao_swhash_elt_pool, sizeof(struct uao_swhash_elt), 589 0, 0, 0, "uaoeltpl", 0, NULL, NULL, M_UVMAOBJ); 590 591 pool_init(&uvm_aobj_pool, sizeof(struct uvm_aobj), 0, 0, 0, 592 "aobjpl", 0, 593 pool_page_alloc_nointr, pool_page_free_nointr, M_UVMAOBJ); 594 } 595 596 /* 597 * uao_reference: add a ref to an aobj 598 * 599 * => aobj must be unlocked 600 * => just lock it and call the locked version 601 */ 602 void 603 uao_reference(uobj) 604 struct uvm_object *uobj; 605 { 606 simple_lock(&uobj->vmobjlock); 607 uao_reference_locked(uobj); 608 simple_unlock(&uobj->vmobjlock); 609 } 610 611 /* 612 * uao_reference_locked: add a ref to an aobj that is already locked 613 * 614 * => aobj must be locked 615 * this needs to be separate from the normal routine 616 * since sometimes we need to add a reference to an aobj when 617 * it's already locked. 618 */ 619 void 620 uao_reference_locked(uobj) 621 struct uvm_object *uobj; 622 { 623 UVMHIST_FUNC("uao_reference"); UVMHIST_CALLED(maphist); 624 625 /* 626 * kernel_object already has plenty of references, leave it alone. 627 */ 628 629 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) 630 return; 631 632 uobj->uo_refs++; /* bump! */ 633 UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)", 634 uobj, uobj->uo_refs,0,0); 635 } 636 637 638 /* 639 * uao_detach: drop a reference to an aobj 640 * 641 * => aobj must be unlocked 642 * => just lock it and call the locked version 643 */ 644 void 645 uao_detach(uobj) 646 struct uvm_object *uobj; 647 { 648 simple_lock(&uobj->vmobjlock); 649 uao_detach_locked(uobj); 650 } 651 652 653 /* 654 * uao_detach_locked: drop a reference to an aobj 655 * 656 * => aobj must be locked, and is unlocked (or freed) upon return. 657 * this needs to be separate from the normal routine 658 * since sometimes we need to detach from an aobj when 659 * it's already locked. 660 */ 661 void 662 uao_detach_locked(uobj) 663 struct uvm_object *uobj; 664 { 665 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 666 struct vm_page *pg; 667 boolean_t busybody; 668 UVMHIST_FUNC("uao_detach"); UVMHIST_CALLED(maphist); 669 670 /* 671 * detaching from kernel_object is a noop. 672 */ 673 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) { 674 simple_unlock(&uobj->vmobjlock); 675 return; 676 } 677 678 UVMHIST_LOG(maphist," (uobj=0x%x) ref=%d", uobj,uobj->uo_refs,0,0); 679 uobj->uo_refs--; /* drop ref! */ 680 if (uobj->uo_refs) { /* still more refs? */ 681 simple_unlock(&uobj->vmobjlock); 682 UVMHIST_LOG(maphist, "<- done (rc>0)", 0,0,0,0); 683 return; 684 } 685 686 /* 687 * remove the aobj from the global list. 688 */ 689 simple_lock(&uao_list_lock); 690 LIST_REMOVE(aobj, u_list); 691 simple_unlock(&uao_list_lock); 692 693 /* 694 * free all the pages that aren't PG_BUSY, 695 * mark for release any that are. 696 */ 697 busybody = FALSE; 698 for (pg = TAILQ_FIRST(&uobj->memq); 699 pg != NULL; 700 pg = TAILQ_NEXT(pg, listq)) { 701 if (pg->flags & PG_BUSY) { 702 pg->flags |= PG_RELEASED; 703 busybody = TRUE; 704 continue; 705 } 706 707 /* zap the mappings, free the swap slot, free the page */ 708 pmap_page_protect(pg, VM_PROT_NONE); 709 uao_dropswap(&aobj->u_obj, pg->offset >> PAGE_SHIFT); 710 uvm_lock_pageq(); 711 uvm_pagefree(pg); 712 uvm_unlock_pageq(); 713 } 714 715 /* 716 * if we found any busy pages, we're done for now. 717 * mark the aobj for death, releasepg will finish up for us. 718 */ 719 if (busybody) { 720 aobj->u_flags |= UAO_FLAG_KILLME; 721 simple_unlock(&aobj->u_obj.vmobjlock); 722 return; 723 } 724 725 /* 726 * finally, free the rest. 727 */ 728 uao_free(aobj); 729 } 730 731 /* 732 * uao_flush: "flush" pages out of a uvm object 733 * 734 * => object should be locked by caller. we may _unlock_ the object 735 * if (and only if) we need to clean a page (PGO_CLEANIT). 736 * XXXJRT Currently, however, we don't. In the case of cleaning 737 * XXXJRT a page, we simply just deactivate it. Should probably 738 * XXXJRT handle this better, in the future (although "flushing" 739 * XXXJRT anonymous memory isn't terribly important). 740 * => if PGO_CLEANIT is not set, then we will neither unlock the object 741 * or block. 742 * => if PGO_ALLPAGE is set, then all pages in the object are valid targets 743 * for flushing. 744 * => NOTE: we rely on the fact that the object's memq is a TAILQ and 745 * that new pages are inserted on the tail end of the list. thus, 746 * we can make a complete pass through the object in one go by starting 747 * at the head and working towards the tail (new pages are put in 748 * front of us). 749 * => NOTE: we are allowed to lock the page queues, so the caller 750 * must not be holding the lock on them [e.g. pagedaemon had 751 * better not call us with the queues locked] 752 * => we return TRUE unless we encountered some sort of I/O error 753 * XXXJRT currently never happens, as we never directly initiate 754 * XXXJRT I/O 755 * 756 * comment on "cleaning" object and PG_BUSY pages: 757 * this routine is holding the lock on the object. the only time 758 * that is can run into a PG_BUSY page that it does not own is if 759 * some other process has started I/O on the page (e.g. either 760 * a pagein or a pageout). if the PG_BUSY page is being paged 761 * in, then it can not be dirty (!PG_CLEAN) because no one has 762 * had a change to modify it yet. if the PG_BUSY page is being 763 * paged out then it means that someone else has already started 764 * cleaning the page for us (how nice!). in this case, if we 765 * have syncio specified, then after we make our pass through the 766 * object we need to wait for the other PG_BUSY pages to clear 767 * off (i.e. we need to do an iosync). also note that once a 768 * page is PG_BUSY is must stary in its object until it is un-busyed. 769 * XXXJRT We never actually do this, as we are "flushing" anonymous 770 * XXXJRT memory, which doesn't have persistent backing store. 771 * 772 * note on page traversal: 773 * we can traverse the pages in an object either by going down the 774 * linked list in "uobj->memq", or we can go over the address range 775 * by page doing hash table lookups for each address. depending 776 * on how many pages are in the object it may be cheaper to do one 777 * or the other. we set "by_list" to true if we are using memq. 778 * if the cost of a hash lookup was equal to the cost of the list 779 * traversal we could compare the number of pages in the start->stop 780 * range to the total number of pages in the object. however, it 781 * seems that a hash table lookup is more expensive than the linked 782 * list traversal, so we multiply the number of pages in the 783 * start->stop range by a penalty which we define below. 784 */ 785 786 #define UAO_HASH_PENALTY 4 /* XXX: a guess */ 787 788 boolean_t 789 uao_flush(uobj, start, stop, flags) 790 struct uvm_object *uobj; 791 voff_t start, stop; 792 int flags; 793 { 794 struct uvm_aobj *aobj = (struct uvm_aobj *) uobj; 795 struct vm_page *pp, *ppnext; 796 boolean_t retval, by_list; 797 voff_t curoff; 798 UVMHIST_FUNC("uao_flush"); UVMHIST_CALLED(maphist); 799 800 curoff = 0; /* XXX: shut up gcc */ 801 802 retval = TRUE; /* default to success */ 803 804 if (flags & PGO_ALLPAGES) { 805 start = 0; 806 stop = aobj->u_pages << PAGE_SHIFT; 807 by_list = TRUE; /* always go by the list */ 808 } else { 809 start = trunc_page(start); 810 stop = round_page(stop); 811 if (stop > (aobj->u_pages << PAGE_SHIFT)) { 812 printf("uao_flush: strange, got an out of range " 813 "flush (fixed)\n"); 814 stop = aobj->u_pages << PAGE_SHIFT; 815 } 816 by_list = (uobj->uo_npages <= 817 ((stop - start) >> PAGE_SHIFT) * UAO_HASH_PENALTY); 818 } 819 820 UVMHIST_LOG(maphist, 821 " flush start=0x%lx, stop=0x%x, by_list=%d, flags=0x%x", 822 start, stop, by_list, flags); 823 824 /* 825 * Don't need to do any work here if we're not freeing 826 * or deactivating pages. 827 */ 828 if ((flags & (PGO_DEACTIVATE|PGO_FREE)) == 0) { 829 UVMHIST_LOG(maphist, 830 "<- done (no work to do)",0,0,0,0); 831 return (retval); 832 } 833 834 /* 835 * now do it. note: we must update ppnext in the body of loop or we 836 * will get stuck. we need to use ppnext because we may free "pp" 837 * before doing the next loop. 838 */ 839 840 if (by_list) { 841 pp = uobj->memq.tqh_first; 842 } else { 843 curoff = start; 844 pp = uvm_pagelookup(uobj, curoff); 845 } 846 847 ppnext = NULL; /* XXX: shut up gcc */ 848 uvm_lock_pageq(); /* page queues locked */ 849 850 /* locked: both page queues and uobj */ 851 for ( ; (by_list && pp != NULL) || 852 (!by_list && curoff < stop) ; pp = ppnext) { 853 if (by_list) { 854 ppnext = TAILQ_NEXT(pp, listq); 855 856 /* range check */ 857 if (pp->offset < start || pp->offset >= stop) 858 continue; 859 } else { 860 curoff += PAGE_SIZE; 861 if (curoff < stop) 862 ppnext = uvm_pagelookup(uobj, curoff); 863 864 /* null check */ 865 if (pp == NULL) 866 continue; 867 } 868 869 switch (flags & (PGO_CLEANIT|PGO_FREE|PGO_DEACTIVATE)) { 870 /* 871 * XXX In these first 3 cases, we always just 872 * XXX deactivate the page. We may want to 873 * XXX handle the different cases more specifically 874 * XXX in the future. 875 */ 876 case PGO_CLEANIT|PGO_FREE: 877 case PGO_CLEANIT|PGO_DEACTIVATE: 878 case PGO_DEACTIVATE: 879 deactivate_it: 880 /* skip the page if it's loaned or wired */ 881 if (pp->loan_count != 0 || 882 pp->wire_count != 0) 883 continue; 884 885 /* zap all mappings for the page. */ 886 pmap_page_protect(pp, VM_PROT_NONE); 887 888 /* ...and deactivate the page. */ 889 uvm_pagedeactivate(pp); 890 891 continue; 892 893 case PGO_FREE: 894 /* 895 * If there are multiple references to 896 * the object, just deactivate the page. 897 */ 898 if (uobj->uo_refs > 1) 899 goto deactivate_it; 900 901 /* XXX skip the page if it's loaned or wired */ 902 if (pp->loan_count != 0 || 903 pp->wire_count != 0) 904 continue; 905 906 /* 907 * mark the page as released if its busy. 908 */ 909 if (pp->flags & PG_BUSY) { 910 pp->flags |= PG_RELEASED; 911 continue; 912 } 913 914 /* zap all mappings for the page. */ 915 pmap_page_protect(pp, VM_PROT_NONE); 916 917 uao_dropswap(uobj, pp->offset >> PAGE_SHIFT); 918 uvm_pagefree(pp); 919 920 continue; 921 922 default: 923 panic("uao_flush: weird flags"); 924 } 925 #ifdef DIAGNOSTIC 926 panic("uao_flush: unreachable code"); 927 #endif 928 } 929 930 uvm_unlock_pageq(); 931 932 UVMHIST_LOG(maphist, 933 "<- done, rv=%d",retval,0,0,0); 934 return (retval); 935 } 936 937 /* 938 * uao_get: fetch me a page 939 * 940 * we have three cases: 941 * 1: page is resident -> just return the page. 942 * 2: page is zero-fill -> allocate a new page and zero it. 943 * 3: page is swapped out -> fetch the page from swap. 944 * 945 * cases 1 and 2 can be handled with PGO_LOCKED, case 3 cannot. 946 * so, if the "center" page hits case 3 (or any page, with PGO_ALLPAGES), 947 * then we will need to return VM_PAGER_UNLOCK. 948 * 949 * => prefer map unlocked (not required) 950 * => object must be locked! we will _unlock_ it before starting any I/O. 951 * => flags: PGO_ALLPAGES: get all of the pages 952 * PGO_LOCKED: fault data structures are locked 953 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 954 * => NOTE: caller must check for released pages!! 955 */ 956 static int 957 uao_get(uobj, offset, pps, npagesp, centeridx, access_type, advice, flags) 958 struct uvm_object *uobj; 959 voff_t offset; 960 struct vm_page **pps; 961 int *npagesp; 962 int centeridx, advice, flags; 963 vm_prot_t access_type; 964 { 965 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 966 voff_t current_offset; 967 vm_page_t ptmp; 968 int lcv, gotpages, maxpages, swslot, rv, pageidx; 969 boolean_t done; 970 UVMHIST_FUNC("uao_get"); UVMHIST_CALLED(pdhist); 971 972 UVMHIST_LOG(pdhist, "aobj=%p offset=%d, flags=%d", 973 aobj, offset, flags,0); 974 975 /* 976 * get number of pages 977 */ 978 maxpages = *npagesp; 979 980 /* 981 * step 1: handled the case where fault data structures are locked. 982 */ 983 984 if (flags & PGO_LOCKED) { 985 /* 986 * step 1a: get pages that are already resident. only do 987 * this if the data structures are locked (i.e. the first 988 * time through). 989 */ 990 991 done = TRUE; /* be optimistic */ 992 gotpages = 0; /* # of pages we got so far */ 993 994 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 995 lcv++, current_offset += PAGE_SIZE) { 996 /* do we care about this page? if not, skip it */ 997 if (pps[lcv] == PGO_DONTCARE) 998 continue; 999 1000 ptmp = uvm_pagelookup(uobj, current_offset); 1001 1002 /* 1003 * if page is new, attempt to allocate the page, 1004 * zero-fill'd. 1005 */ 1006 if (ptmp == NULL && uao_find_swslot(aobj, 1007 current_offset >> PAGE_SHIFT) == 0) { 1008 ptmp = uvm_pagealloc(uobj, current_offset, 1009 NULL, UVM_PGA_ZERO); 1010 if (ptmp) { 1011 /* new page */ 1012 ptmp->flags &= ~(PG_BUSY|PG_FAKE); 1013 ptmp->pqflags |= PQ_AOBJ; 1014 UVM_PAGE_OWN(ptmp, NULL); 1015 } 1016 } 1017 1018 /* 1019 * to be useful must get a non-busy, non-released page 1020 */ 1021 if (ptmp == NULL || 1022 (ptmp->flags & (PG_BUSY|PG_RELEASED)) != 0) { 1023 if (lcv == centeridx || 1024 (flags & PGO_ALLPAGES) != 0) 1025 /* need to do a wait or I/O! */ 1026 done = FALSE; 1027 continue; 1028 } 1029 1030 /* 1031 * useful page: busy/lock it and plug it in our 1032 * result array 1033 */ 1034 /* caller must un-busy this page */ 1035 ptmp->flags |= PG_BUSY; 1036 UVM_PAGE_OWN(ptmp, "uao_get1"); 1037 pps[lcv] = ptmp; 1038 gotpages++; 1039 1040 } /* "for" lcv loop */ 1041 1042 /* 1043 * step 1b: now we've either done everything needed or we 1044 * to unlock and do some waiting or I/O. 1045 */ 1046 1047 UVMHIST_LOG(pdhist, "<- done (done=%d)", done, 0,0,0); 1048 1049 *npagesp = gotpages; 1050 if (done) 1051 /* bingo! */ 1052 return(VM_PAGER_OK); 1053 else 1054 /* EEK! Need to unlock and I/O */ 1055 return(VM_PAGER_UNLOCK); 1056 } 1057 1058 /* 1059 * step 2: get non-resident or busy pages. 1060 * object is locked. data structures are unlocked. 1061 */ 1062 1063 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 1064 lcv++, current_offset += PAGE_SIZE) { 1065 1066 /* 1067 * - skip over pages we've already gotten or don't want 1068 * - skip over pages we don't _have_ to get 1069 */ 1070 1071 if (pps[lcv] != NULL || 1072 (lcv != centeridx && (flags & PGO_ALLPAGES) == 0)) 1073 continue; 1074 1075 pageidx = current_offset >> PAGE_SHIFT; 1076 1077 /* 1078 * we have yet to locate the current page (pps[lcv]). we 1079 * first look for a page that is already at the current offset. 1080 * if we find a page, we check to see if it is busy or 1081 * released. if that is the case, then we sleep on the page 1082 * until it is no longer busy or released and repeat the lookup. 1083 * if the page we found is neither busy nor released, then we 1084 * busy it (so we own it) and plug it into pps[lcv]. this 1085 * 'break's the following while loop and indicates we are 1086 * ready to move on to the next page in the "lcv" loop above. 1087 * 1088 * if we exit the while loop with pps[lcv] still set to NULL, 1089 * then it means that we allocated a new busy/fake/clean page 1090 * ptmp in the object and we need to do I/O to fill in the data. 1091 */ 1092 1093 /* top of "pps" while loop */ 1094 while (pps[lcv] == NULL) { 1095 /* look for a resident page */ 1096 ptmp = uvm_pagelookup(uobj, current_offset); 1097 1098 /* not resident? allocate one now (if we can) */ 1099 if (ptmp == NULL) { 1100 1101 ptmp = uvm_pagealloc(uobj, current_offset, 1102 NULL, 0); 1103 1104 /* out of RAM? */ 1105 if (ptmp == NULL) { 1106 simple_unlock(&uobj->vmobjlock); 1107 UVMHIST_LOG(pdhist, 1108 "sleeping, ptmp == NULL\n",0,0,0,0); 1109 uvm_wait("uao_getpage"); 1110 simple_lock(&uobj->vmobjlock); 1111 /* goto top of pps while loop */ 1112 continue; 1113 } 1114 1115 /* 1116 * safe with PQ's unlocked: because we just 1117 * alloc'd the page 1118 */ 1119 ptmp->pqflags |= PQ_AOBJ; 1120 1121 /* 1122 * got new page ready for I/O. break pps while 1123 * loop. pps[lcv] is still NULL. 1124 */ 1125 break; 1126 } 1127 1128 /* page is there, see if we need to wait on it */ 1129 if ((ptmp->flags & (PG_BUSY|PG_RELEASED)) != 0) { 1130 ptmp->flags |= PG_WANTED; 1131 UVMHIST_LOG(pdhist, 1132 "sleeping, ptmp->flags 0x%x\n", 1133 ptmp->flags,0,0,0); 1134 UVM_UNLOCK_AND_WAIT(ptmp, &uobj->vmobjlock, 1135 FALSE, "uao_get", 0); 1136 simple_lock(&uobj->vmobjlock); 1137 continue; /* goto top of pps while loop */ 1138 } 1139 1140 /* 1141 * if we get here then the page has become resident and 1142 * unbusy between steps 1 and 2. we busy it now (so we 1143 * own it) and set pps[lcv] (so that we exit the while 1144 * loop). 1145 */ 1146 /* we own it, caller must un-busy */ 1147 ptmp->flags |= PG_BUSY; 1148 UVM_PAGE_OWN(ptmp, "uao_get2"); 1149 pps[lcv] = ptmp; 1150 } 1151 1152 /* 1153 * if we own the valid page at the correct offset, pps[lcv] will 1154 * point to it. nothing more to do except go to the next page. 1155 */ 1156 if (pps[lcv]) 1157 continue; /* next lcv */ 1158 1159 /* 1160 * we have a "fake/busy/clean" page that we just allocated. 1161 * do the needed "i/o", either reading from swap or zeroing. 1162 */ 1163 swslot = uao_find_swslot(aobj, pageidx); 1164 1165 /* 1166 * just zero the page if there's nothing in swap. 1167 */ 1168 if (swslot == 0) 1169 { 1170 /* 1171 * page hasn't existed before, just zero it. 1172 */ 1173 uvm_pagezero(ptmp); 1174 } else { 1175 UVMHIST_LOG(pdhist, "pagein from swslot %d", 1176 swslot, 0,0,0); 1177 1178 /* 1179 * page in the swapped-out page. 1180 * unlock object for i/o, relock when done. 1181 */ 1182 simple_unlock(&uobj->vmobjlock); 1183 rv = uvm_swap_get(ptmp, swslot, PGO_SYNCIO); 1184 simple_lock(&uobj->vmobjlock); 1185 1186 /* 1187 * I/O done. check for errors. 1188 */ 1189 if (rv != VM_PAGER_OK) 1190 { 1191 UVMHIST_LOG(pdhist, "<- done (error=%d)", 1192 rv,0,0,0); 1193 if (ptmp->flags & PG_WANTED) 1194 wakeup(ptmp); 1195 1196 /* 1197 * remove the swap slot from the aobj 1198 * and mark the aobj as having no real slot. 1199 * don't free the swap slot, thus preventing 1200 * it from being used again. 1201 */ 1202 swslot = uao_set_swslot(&aobj->u_obj, pageidx, 1203 SWSLOT_BAD); 1204 uvm_swap_markbad(swslot, 1); 1205 1206 ptmp->flags &= ~(PG_WANTED|PG_BUSY); 1207 UVM_PAGE_OWN(ptmp, NULL); 1208 uvm_lock_pageq(); 1209 uvm_pagefree(ptmp); 1210 uvm_unlock_pageq(); 1211 1212 simple_unlock(&uobj->vmobjlock); 1213 return (rv); 1214 } 1215 } 1216 1217 /* 1218 * we got the page! clear the fake flag (indicates valid 1219 * data now in page) and plug into our result array. note 1220 * that page is still busy. 1221 * 1222 * it is the callers job to: 1223 * => check if the page is released 1224 * => unbusy the page 1225 * => activate the page 1226 */ 1227 1228 ptmp->flags &= ~PG_FAKE; /* data is valid ... */ 1229 pmap_clear_modify(ptmp); /* ... and clean */ 1230 pps[lcv] = ptmp; 1231 1232 } /* lcv loop */ 1233 1234 /* 1235 * finally, unlock object and return. 1236 */ 1237 1238 simple_unlock(&uobj->vmobjlock); 1239 UVMHIST_LOG(pdhist, "<- done (OK)",0,0,0,0); 1240 return(VM_PAGER_OK); 1241 } 1242 1243 /* 1244 * uao_releasepg: handle released page in an aobj 1245 * 1246 * => "pg" is a PG_BUSY [caller owns it], PG_RELEASED page that we need 1247 * to dispose of. 1248 * => caller must handle PG_WANTED case 1249 * => called with page's object locked, pageq's unlocked 1250 * => returns TRUE if page's object is still alive, FALSE if we 1251 * killed the page's object. if we return TRUE, then we 1252 * return with the object locked. 1253 * => if (nextpgp != NULL) => we return the next page on the queue, and return 1254 * with the page queues locked [for pagedaemon] 1255 * => if (nextpgp == NULL) => we return with page queues unlocked [normal case] 1256 * => we kill the aobj if it is not referenced and we are suppose to 1257 * kill it ("KILLME"). 1258 */ 1259 static boolean_t 1260 uao_releasepg(pg, nextpgp) 1261 struct vm_page *pg; 1262 struct vm_page **nextpgp; /* OUT */ 1263 { 1264 struct uvm_aobj *aobj = (struct uvm_aobj *) pg->uobject; 1265 1266 #ifdef DIAGNOSTIC 1267 if ((pg->flags & PG_RELEASED) == 0) 1268 panic("uao_releasepg: page not released!"); 1269 #endif 1270 1271 /* 1272 * dispose of the page [caller handles PG_WANTED] and swap slot. 1273 */ 1274 pmap_page_protect(pg, VM_PROT_NONE); 1275 uao_dropswap(&aobj->u_obj, pg->offset >> PAGE_SHIFT); 1276 uvm_lock_pageq(); 1277 if (nextpgp) 1278 *nextpgp = TAILQ_NEXT(pg, pageq); /* next page for daemon */ 1279 uvm_pagefree(pg); 1280 if (!nextpgp) 1281 uvm_unlock_pageq(); /* keep locked for daemon */ 1282 1283 /* 1284 * if we're not killing the object, we're done. 1285 */ 1286 if ((aobj->u_flags & UAO_FLAG_KILLME) == 0) 1287 return TRUE; 1288 KASSERT(aobj->u_obj.uo_refs == 0); 1289 1290 /* 1291 * if there are still pages in the object, we're done for now. 1292 */ 1293 if (aobj->u_obj.uo_npages != 0) 1294 return TRUE; 1295 1296 #ifdef DIAGNOSTIC 1297 if (TAILQ_FIRST(&aobj->u_obj.memq)) 1298 panic("uvn_releasepg: pages in object with npages == 0"); 1299 #endif 1300 1301 /* 1302 * finally, free the rest. 1303 */ 1304 uao_free(aobj); 1305 1306 return FALSE; 1307 } 1308 1309 1310 /* 1311 * uao_dropswap: release any swap resources from this aobj page. 1312 * 1313 * => aobj must be locked or have a reference count of 0. 1314 */ 1315 1316 void 1317 uao_dropswap(uobj, pageidx) 1318 struct uvm_object *uobj; 1319 int pageidx; 1320 { 1321 int slot; 1322 1323 slot = uao_set_swslot(uobj, pageidx, 0); 1324 if (slot) { 1325 uvm_swap_free(slot, 1); 1326 } 1327 } 1328 1329 1330 /* 1331 * page in every page in every aobj that is paged-out to a range of swslots. 1332 * 1333 * => nothing should be locked. 1334 * => returns TRUE if pagein was aborted due to lack of memory. 1335 */ 1336 boolean_t 1337 uao_swap_off(startslot, endslot) 1338 int startslot, endslot; 1339 { 1340 struct uvm_aobj *aobj, *nextaobj; 1341 1342 /* 1343 * walk the list of all aobjs. 1344 */ 1345 1346 restart: 1347 simple_lock(&uao_list_lock); 1348 1349 for (aobj = LIST_FIRST(&uao_list); 1350 aobj != NULL; 1351 aobj = nextaobj) { 1352 boolean_t rv; 1353 1354 /* 1355 * try to get the object lock, 1356 * start all over if we fail. 1357 * most of the time we'll get the aobj lock, 1358 * so this should be a rare case. 1359 */ 1360 if (!simple_lock_try(&aobj->u_obj.vmobjlock)) { 1361 simple_unlock(&uao_list_lock); 1362 goto restart; 1363 } 1364 1365 /* 1366 * add a ref to the aobj so it doesn't disappear 1367 * while we're working. 1368 */ 1369 uao_reference_locked(&aobj->u_obj); 1370 1371 /* 1372 * now it's safe to unlock the uao list. 1373 */ 1374 simple_unlock(&uao_list_lock); 1375 1376 /* 1377 * page in any pages in the swslot range. 1378 * if there's an error, abort and return the error. 1379 */ 1380 rv = uao_pagein(aobj, startslot, endslot); 1381 if (rv) { 1382 uao_detach_locked(&aobj->u_obj); 1383 return rv; 1384 } 1385 1386 /* 1387 * we're done with this aobj. 1388 * relock the list and drop our ref on the aobj. 1389 */ 1390 simple_lock(&uao_list_lock); 1391 nextaobj = LIST_NEXT(aobj, u_list); 1392 uao_detach_locked(&aobj->u_obj); 1393 } 1394 1395 /* 1396 * done with traversal, unlock the list 1397 */ 1398 simple_unlock(&uao_list_lock); 1399 return FALSE; 1400 } 1401 1402 1403 /* 1404 * page in any pages from aobj in the given range. 1405 * 1406 * => aobj must be locked and is returned locked. 1407 * => returns TRUE if pagein was aborted due to lack of memory. 1408 */ 1409 static boolean_t 1410 uao_pagein(aobj, startslot, endslot) 1411 struct uvm_aobj *aobj; 1412 int startslot, endslot; 1413 { 1414 boolean_t rv; 1415 1416 if (UAO_USES_SWHASH(aobj)) { 1417 struct uao_swhash_elt *elt; 1418 int bucket; 1419 1420 restart: 1421 for (bucket = aobj->u_swhashmask; bucket >= 0; bucket--) { 1422 for (elt = LIST_FIRST(&aobj->u_swhash[bucket]); 1423 elt != NULL; 1424 elt = LIST_NEXT(elt, list)) { 1425 int i; 1426 1427 for (i = 0; i < UAO_SWHASH_CLUSTER_SIZE; i++) { 1428 int slot = elt->slots[i]; 1429 1430 /* 1431 * if the slot isn't in range, skip it. 1432 */ 1433 if (slot < startslot || 1434 slot >= endslot) { 1435 continue; 1436 } 1437 1438 /* 1439 * process the page, 1440 * the start over on this object 1441 * since the swhash elt 1442 * may have been freed. 1443 */ 1444 rv = uao_pagein_page(aobj, 1445 UAO_SWHASH_ELT_PAGEIDX_BASE(elt) + i); 1446 if (rv) { 1447 return rv; 1448 } 1449 goto restart; 1450 } 1451 } 1452 } 1453 } else { 1454 int i; 1455 1456 for (i = 0; i < aobj->u_pages; i++) { 1457 int slot = aobj->u_swslots[i]; 1458 1459 /* 1460 * if the slot isn't in range, skip it 1461 */ 1462 if (slot < startslot || slot >= endslot) { 1463 continue; 1464 } 1465 1466 /* 1467 * process the page. 1468 */ 1469 rv = uao_pagein_page(aobj, i); 1470 if (rv) { 1471 return rv; 1472 } 1473 } 1474 } 1475 1476 return FALSE; 1477 } 1478 1479 /* 1480 * page in a page from an aobj. used for swap_off. 1481 * returns TRUE if pagein was aborted due to lack of memory. 1482 * 1483 * => aobj must be locked and is returned locked. 1484 */ 1485 static boolean_t 1486 uao_pagein_page(aobj, pageidx) 1487 struct uvm_aobj *aobj; 1488 int pageidx; 1489 { 1490 struct vm_page *pg; 1491 int rv, slot, npages; 1492 1493 pg = NULL; 1494 npages = 1; 1495 /* locked: aobj */ 1496 rv = uao_get(&aobj->u_obj, pageidx << PAGE_SHIFT, 1497 &pg, &npages, 0, VM_PROT_READ|VM_PROT_WRITE, 0, 0); 1498 /* unlocked: aobj */ 1499 1500 /* 1501 * relock and finish up. 1502 */ 1503 simple_lock(&aobj->u_obj.vmobjlock); 1504 1505 switch (rv) { 1506 case VM_PAGER_OK: 1507 break; 1508 1509 case VM_PAGER_ERROR: 1510 case VM_PAGER_REFAULT: 1511 /* 1512 * nothing more to do on errors. 1513 * VM_PAGER_REFAULT can only mean that the anon was freed, 1514 * so again there's nothing to do. 1515 */ 1516 return FALSE; 1517 1518 #ifdef DIAGNOSTIC 1519 default: 1520 panic("uao_pagein_page: uao_get -> %d\n", rv); 1521 #endif 1522 } 1523 1524 #ifdef DIAGNOSTIC 1525 /* 1526 * this should never happen, since we have a reference on the aobj. 1527 */ 1528 if (pg->flags & PG_RELEASED) { 1529 panic("uao_pagein_page: found PG_RELEASED page?\n"); 1530 } 1531 #endif 1532 1533 /* 1534 * ok, we've got the page now. 1535 * mark it as dirty, clear its swslot and un-busy it. 1536 */ 1537 slot = uao_set_swslot(&aobj->u_obj, pageidx, 0); 1538 uvm_swap_free(slot, 1); 1539 pg->flags &= ~(PG_BUSY|PG_CLEAN|PG_FAKE); 1540 UVM_PAGE_OWN(pg, NULL); 1541 1542 /* 1543 * deactivate the page (to put it on a page queue). 1544 */ 1545 pmap_clear_reference(pg); 1546 pmap_page_protect(pg, VM_PROT_NONE); 1547 uvm_lock_pageq(); 1548 uvm_pagedeactivate(pg); 1549 uvm_unlock_pageq(); 1550 1551 return FALSE; 1552 } 1553