1 /* $OpenBSD: uvm_aobj.c,v 1.26 2002/03/14 01:27:18 millert Exp $ */ 2 /* $NetBSD: uvm_aobj.c,v 1.39 2001/02/18 21:19:08 chs Exp $ */ 3 4 /* 5 * Copyright (c) 1998 Chuck Silvers, Charles D. Cranor and 6 * Washington University. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by Charles D. Cranor and 20 * Washington University. 21 * 4. The name of the author may not be used to endorse or promote products 22 * derived from this software without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 * 35 * from: Id: uvm_aobj.c,v 1.1.2.5 1998/02/06 05:14:38 chs Exp 36 */ 37 /* 38 * uvm_aobj.c: anonymous memory uvm_object pager 39 * 40 * author: Chuck Silvers <chuq@chuq.com> 41 * started: Jan-1998 42 * 43 * - design mostly from Chuck Cranor 44 */ 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/proc.h> 49 #include <sys/malloc.h> 50 #include <sys/kernel.h> 51 #include <sys/pool.h> 52 #include <sys/kernel.h> 53 54 #include <uvm/uvm.h> 55 56 /* 57 * an aobj manages anonymous-memory backed uvm_objects. in addition 58 * to keeping the list of resident pages, it also keeps a list of 59 * allocated swap blocks. depending on the size of the aobj this list 60 * of allocated swap blocks is either stored in an array (small objects) 61 * or in a hash table (large objects). 62 */ 63 64 /* 65 * local structures 66 */ 67 68 /* 69 * for hash tables, we break the address space of the aobj into blocks 70 * of UAO_SWHASH_CLUSTER_SIZE pages. we require the cluster size to 71 * be a power of two. 72 */ 73 74 #define UAO_SWHASH_CLUSTER_SHIFT 4 75 #define UAO_SWHASH_CLUSTER_SIZE (1 << UAO_SWHASH_CLUSTER_SHIFT) 76 77 /* get the "tag" for this page index */ 78 #define UAO_SWHASH_ELT_TAG(PAGEIDX) \ 79 ((PAGEIDX) >> UAO_SWHASH_CLUSTER_SHIFT) 80 81 /* given an ELT and a page index, find the swap slot */ 82 #define UAO_SWHASH_ELT_PAGESLOT(ELT, PAGEIDX) \ 83 ((ELT)->slots[(PAGEIDX) & (UAO_SWHASH_CLUSTER_SIZE - 1)]) 84 85 /* given an ELT, return its pageidx base */ 86 #define UAO_SWHASH_ELT_PAGEIDX_BASE(ELT) \ 87 ((ELT)->tag << UAO_SWHASH_CLUSTER_SHIFT) 88 89 /* 90 * the swhash hash function 91 */ 92 #define UAO_SWHASH_HASH(AOBJ, PAGEIDX) \ 93 (&(AOBJ)->u_swhash[(((PAGEIDX) >> UAO_SWHASH_CLUSTER_SHIFT) \ 94 & (AOBJ)->u_swhashmask)]) 95 96 /* 97 * the swhash threshhold determines if we will use an array or a 98 * hash table to store the list of allocated swap blocks. 99 */ 100 101 #define UAO_SWHASH_THRESHOLD (UAO_SWHASH_CLUSTER_SIZE * 4) 102 #define UAO_USES_SWHASH(AOBJ) \ 103 ((AOBJ)->u_pages > UAO_SWHASH_THRESHOLD) /* use hash? */ 104 105 /* 106 * the number of buckets in a swhash, with an upper bound 107 */ 108 #define UAO_SWHASH_MAXBUCKETS 256 109 #define UAO_SWHASH_BUCKETS(AOBJ) \ 110 (min((AOBJ)->u_pages >> UAO_SWHASH_CLUSTER_SHIFT, \ 111 UAO_SWHASH_MAXBUCKETS)) 112 113 114 /* 115 * uao_swhash_elt: when a hash table is being used, this structure defines 116 * the format of an entry in the bucket list. 117 */ 118 119 struct uao_swhash_elt { 120 LIST_ENTRY(uao_swhash_elt) list; /* the hash list */ 121 voff_t tag; /* our 'tag' */ 122 int count; /* our number of active slots */ 123 int slots[UAO_SWHASH_CLUSTER_SIZE]; /* the slots */ 124 }; 125 126 /* 127 * uao_swhash: the swap hash table structure 128 */ 129 130 LIST_HEAD(uao_swhash, uao_swhash_elt); 131 132 /* 133 * uao_swhash_elt_pool: pool of uao_swhash_elt structures 134 */ 135 136 struct pool uao_swhash_elt_pool; 137 138 /* 139 * uvm_aobj: the actual anon-backed uvm_object 140 * 141 * => the uvm_object is at the top of the structure, this allows 142 * (struct uvm_device *) == (struct uvm_object *) 143 * => only one of u_swslots and u_swhash is used in any given aobj 144 */ 145 146 struct uvm_aobj { 147 struct uvm_object u_obj; /* has: lock, pgops, memq, #pages, #refs */ 148 int u_pages; /* number of pages in entire object */ 149 int u_flags; /* the flags (see uvm_aobj.h) */ 150 int *u_swslots; /* array of offset->swapslot mappings */ 151 /* 152 * hashtable of offset->swapslot mappings 153 * (u_swhash is an array of bucket heads) 154 */ 155 struct uao_swhash *u_swhash; 156 u_long u_swhashmask; /* mask for hashtable */ 157 LIST_ENTRY(uvm_aobj) u_list; /* global list of aobjs */ 158 }; 159 160 /* 161 * uvm_aobj_pool: pool of uvm_aobj structures 162 */ 163 164 struct pool uvm_aobj_pool; 165 166 /* 167 * local functions 168 */ 169 170 static struct uao_swhash_elt *uao_find_swhash_elt(struct uvm_aobj *, 171 int, boolean_t); 172 static int uao_find_swslot(struct uvm_aobj *, int); 173 static boolean_t uao_flush(struct uvm_object *, 174 voff_t, voff_t, int); 175 static void uao_free(struct uvm_aobj *); 176 static int uao_get(struct uvm_object *, voff_t, 177 vm_page_t *, int *, int, 178 vm_prot_t, int, int); 179 static boolean_t uao_releasepg(struct vm_page *, 180 struct vm_page **); 181 static boolean_t uao_pagein(struct uvm_aobj *, int, int); 182 static boolean_t uao_pagein_page(struct uvm_aobj *, int); 183 184 /* 185 * aobj_pager 186 * 187 * note that some functions (e.g. put) are handled elsewhere 188 */ 189 190 struct uvm_pagerops aobj_pager = { 191 NULL, /* init */ 192 uao_reference, /* reference */ 193 uao_detach, /* detach */ 194 NULL, /* fault */ 195 uao_flush, /* flush */ 196 uao_get, /* get */ 197 NULL, /* put (done by pagedaemon) */ 198 NULL, /* cluster */ 199 NULL, /* mk_pcluster */ 200 uao_releasepg /* releasepg */ 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 simple_lock_data_t uao_list_lock; 209 210 211 /* 212 * functions 213 */ 214 215 /* 216 * hash table/array related functions 217 */ 218 219 /* 220 * uao_find_swhash_elt: find (or create) a hash table entry for a page 221 * offset. 222 * 223 * => the object should be locked by the caller 224 */ 225 226 static struct uao_swhash_elt * 227 uao_find_swhash_elt(aobj, pageidx, create) 228 struct uvm_aobj *aobj; 229 int pageidx; 230 boolean_t create; 231 { 232 struct uao_swhash *swhash; 233 struct uao_swhash_elt *elt; 234 voff_t page_tag; 235 236 swhash = UAO_SWHASH_HASH(aobj, pageidx); /* first hash to get bucket */ 237 page_tag = UAO_SWHASH_ELT_TAG(pageidx); /* tag to search for */ 238 239 /* 240 * now search the bucket for the requested tag 241 */ 242 LIST_FOREACH(elt, swhash, list) { 243 if (elt->tag == page_tag) 244 return(elt); 245 } 246 247 /* fail now if we are not allowed to create a new entry in the bucket */ 248 if (!create) 249 return NULL; 250 251 252 /* 253 * allocate a new entry for the bucket and init/insert it in 254 */ 255 elt = pool_get(&uao_swhash_elt_pool, PR_WAITOK); 256 LIST_INSERT_HEAD(swhash, elt, list); 257 elt->tag = page_tag; 258 elt->count = 0; 259 memset(elt->slots, 0, sizeof(elt->slots)); 260 261 return(elt); 262 } 263 264 /* 265 * uao_find_swslot: find the swap slot number for an aobj/pageidx 266 * 267 * => object must be locked by caller 268 */ 269 __inline static int 270 uao_find_swslot(aobj, pageidx) 271 struct uvm_aobj *aobj; 272 int pageidx; 273 { 274 275 /* 276 * if noswap flag is set, then we never return a slot 277 */ 278 279 if (aobj->u_flags & UAO_FLAG_NOSWAP) 280 return(0); 281 282 /* 283 * if hashing, look in hash table. 284 */ 285 286 if (UAO_USES_SWHASH(aobj)) { 287 struct uao_swhash_elt *elt = 288 uao_find_swhash_elt(aobj, pageidx, FALSE); 289 290 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 return(aobj->u_swslots[pageidx]); 300 } 301 302 /* 303 * uao_set_swslot: set the swap slot for a page in an aobj. 304 * 305 * => setting a slot to zero frees the slot 306 * => object must be locked by caller 307 */ 308 int 309 uao_set_swslot(uobj, pageidx, slot) 310 struct uvm_object *uobj; 311 int pageidx, slot; 312 { 313 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 314 int oldslot; 315 UVMHIST_FUNC("uao_set_swslot"); UVMHIST_CALLED(pdhist); 316 UVMHIST_LOG(pdhist, "aobj %p pageidx %d slot %d", 317 aobj, pageidx, slot, 0); 318 319 /* 320 * if noswap flag is set, then we can't set a slot 321 */ 322 323 if (aobj->u_flags & UAO_FLAG_NOSWAP) { 324 325 if (slot == 0) 326 return(0); /* a clear is ok */ 327 328 /* but a set is not */ 329 printf("uao_set_swslot: uobj = %p\n", uobj); 330 panic("uao_set_swslot: attempt to set a slot on a NOSWAP object"); 331 } 332 333 /* 334 * are we using a hash table? if so, add it in the hash. 335 */ 336 337 if (UAO_USES_SWHASH(aobj)) { 338 339 /* 340 * Avoid allocating an entry just to free it again if 341 * the page had not swap slot in the first place, and 342 * we are freeing. 343 */ 344 345 struct uao_swhash_elt *elt = 346 uao_find_swhash_elt(aobj, pageidx, slot ? TRUE : FALSE); 347 if (elt == NULL) { 348 KASSERT(slot == 0); 349 return (0); 350 } 351 352 oldslot = UAO_SWHASH_ELT_PAGESLOT(elt, pageidx); 353 UAO_SWHASH_ELT_PAGESLOT(elt, pageidx) = slot; 354 355 /* 356 * now adjust the elt's reference counter and free it if we've 357 * dropped it to zero. 358 */ 359 360 /* an allocation? */ 361 if (slot) { 362 if (oldslot == 0) 363 elt->count++; 364 } else { /* freeing slot ... */ 365 if (oldslot) /* to be safe */ 366 elt->count--; 367 368 if (elt->count == 0) { 369 LIST_REMOVE(elt, list); 370 pool_put(&uao_swhash_elt_pool, elt); 371 } 372 } 373 } else { 374 /* we are using an array */ 375 oldslot = aobj->u_swslots[pageidx]; 376 aobj->u_swslots[pageidx] = slot; 377 } 378 return (oldslot); 379 } 380 381 /* 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 static void 391 uao_free(aobj) 392 struct uvm_aobj *aobj; 393 { 394 395 simple_unlock(&aobj->u_obj.vmobjlock); 396 397 if (UAO_USES_SWHASH(aobj)) { 398 int i, hashbuckets = aobj->u_swhashmask + 1; 399 400 /* 401 * free the swslots from each hash bucket, 402 * then the hash bucket, and finally the hash table itself. 403 */ 404 for (i = 0; i < hashbuckets; i++) { 405 struct uao_swhash_elt *elt, *next; 406 407 for (elt = LIST_FIRST(&aobj->u_swhash[i]); 408 elt != NULL; 409 elt = next) { 410 int j; 411 412 for (j = 0; j < UAO_SWHASH_CLUSTER_SIZE; j++) { 413 int slot = elt->slots[j]; 414 415 if (slot == 0) { 416 continue; 417 } 418 uvm_swap_free(slot, 1); 419 420 /* 421 * this page is no longer 422 * only in swap. 423 */ 424 simple_lock(&uvm.swap_data_lock); 425 uvmexp.swpgonly--; 426 simple_unlock(&uvm.swap_data_lock); 427 } 428 429 next = LIST_NEXT(elt, list); 430 pool_put(&uao_swhash_elt_pool, elt); 431 } 432 } 433 free(aobj->u_swhash, M_UVMAOBJ); 434 } else { 435 int i; 436 437 /* 438 * free the array 439 */ 440 441 for (i = 0; i < aobj->u_pages; i++) { 442 int slot = aobj->u_swslots[i]; 443 444 if (slot) { 445 uvm_swap_free(slot, 1); 446 447 /* this page is no longer only in swap. */ 448 simple_lock(&uvm.swap_data_lock); 449 uvmexp.swpgonly--; 450 simple_unlock(&uvm.swap_data_lock); 451 } 452 } 453 free(aobj->u_swslots, M_UVMAOBJ); 454 } 455 456 /* 457 * finally free the aobj itself 458 */ 459 pool_put(&uvm_aobj_pool, aobj); 460 } 461 462 /* 463 * pager functions 464 */ 465 466 /* 467 * uao_create: create an aobj of the given size and return its uvm_object. 468 * 469 * => for normal use, flags are always zero 470 * => for the kernel object, the flags are: 471 * UAO_FLAG_KERNOBJ - allocate the kernel object (can only happen once) 472 * UAO_FLAG_KERNSWAP - enable swapping of kernel object (" ") 473 */ 474 struct uvm_object * 475 uao_create(size, flags) 476 vsize_t size; 477 int flags; 478 { 479 static struct uvm_aobj kernel_object_store; /* home of kernel_object */ 480 static int kobj_alloced = 0; /* not allocated yet */ 481 int pages = round_page(size) >> PAGE_SHIFT; 482 struct uvm_aobj *aobj; 483 484 /* 485 * malloc a new aobj unless we are asked for the kernel object 486 */ 487 if (flags & UAO_FLAG_KERNOBJ) { /* want kernel object? */ 488 if (kobj_alloced) 489 panic("uao_create: kernel object already allocated"); 490 491 aobj = &kernel_object_store; 492 aobj->u_pages = pages; 493 aobj->u_flags = UAO_FLAG_NOSWAP; /* no swap to start */ 494 /* we are special, we never die */ 495 aobj->u_obj.uo_refs = UVM_OBJ_KERN; 496 kobj_alloced = UAO_FLAG_KERNOBJ; 497 } else if (flags & UAO_FLAG_KERNSWAP) { 498 aobj = &kernel_object_store; 499 if (kobj_alloced != UAO_FLAG_KERNOBJ) 500 panic("uao_create: asked to enable swap on kernel object"); 501 kobj_alloced = UAO_FLAG_KERNSWAP; 502 } else { /* normal object */ 503 aobj = pool_get(&uvm_aobj_pool, PR_WAITOK); 504 aobj->u_pages = pages; 505 aobj->u_flags = 0; /* normal object */ 506 aobj->u_obj.uo_refs = 1; /* start with 1 reference */ 507 } 508 509 /* 510 * allocate hash/array if necessary 511 * 512 * note: in the KERNSWAP case no need to worry about locking since 513 * we are still booting we should be the only thread around. 514 */ 515 if (flags == 0 || (flags & UAO_FLAG_KERNSWAP) != 0) { 516 int mflags = (flags & UAO_FLAG_KERNSWAP) != 0 ? 517 M_NOWAIT : M_WAITOK; 518 519 /* allocate hash table or array depending on object size */ 520 if (UAO_USES_SWHASH(aobj)) { 521 aobj->u_swhash = hashinit(UAO_SWHASH_BUCKETS(aobj), 522 M_UVMAOBJ, mflags, &aobj->u_swhashmask); 523 if (aobj->u_swhash == NULL) 524 panic("uao_create: hashinit swhash failed"); 525 } else { 526 aobj->u_swslots = malloc(pages * sizeof(int), 527 M_UVMAOBJ, mflags); 528 if (aobj->u_swslots == NULL) 529 panic("uao_create: malloc swslots failed"); 530 memset(aobj->u_swslots, 0, pages * sizeof(int)); 531 } 532 533 if (flags) { 534 aobj->u_flags &= ~UAO_FLAG_NOSWAP; /* clear noswap */ 535 return(&aobj->u_obj); 536 /* done! */ 537 } 538 } 539 540 /* 541 * init aobj fields 542 */ 543 simple_lock_init(&aobj->u_obj.vmobjlock); 544 aobj->u_obj.pgops = &aobj_pager; 545 TAILQ_INIT(&aobj->u_obj.memq); 546 aobj->u_obj.uo_npages = 0; 547 548 /* 549 * now that aobj is ready, add it to the global list 550 */ 551 simple_lock(&uao_list_lock); 552 LIST_INSERT_HEAD(&uao_list, aobj, u_list); 553 simple_unlock(&uao_list_lock); 554 555 /* 556 * done! 557 */ 558 return(&aobj->u_obj); 559 } 560 561 562 563 /* 564 * uao_init: set up aobj pager subsystem 565 * 566 * => called at boot time from uvm_pager_init() 567 */ 568 void 569 uao_init() 570 { 571 static int uao_initialized; 572 573 if (uao_initialized) 574 return; 575 uao_initialized = TRUE; 576 577 LIST_INIT(&uao_list); 578 simple_lock_init(&uao_list_lock); 579 580 /* 581 * NOTE: Pages fror this pool must not come from a pageable 582 * kernel map! 583 */ 584 pool_init(&uao_swhash_elt_pool, sizeof(struct uao_swhash_elt), 585 0, 0, 0, "uaoeltpl", &pool_allocator_nointr); 586 587 pool_init(&uvm_aobj_pool, sizeof(struct uvm_aobj), 0, 0, 0, 588 "aobjpl", &pool_allocator_nointr); 589 } 590 591 /* 592 * uao_reference: add a ref to an aobj 593 * 594 * => aobj must be unlocked 595 * => just lock it and call the locked version 596 */ 597 void 598 uao_reference(uobj) 599 struct uvm_object *uobj; 600 { 601 simple_lock(&uobj->vmobjlock); 602 uao_reference_locked(uobj); 603 simple_unlock(&uobj->vmobjlock); 604 } 605 606 /* 607 * uao_reference_locked: add a ref to an aobj that is already locked 608 * 609 * => aobj must be locked 610 * this needs to be separate from the normal routine 611 * since sometimes we need to add a reference to an aobj when 612 * it's already locked. 613 */ 614 void 615 uao_reference_locked(uobj) 616 struct uvm_object *uobj; 617 { 618 UVMHIST_FUNC("uao_reference"); UVMHIST_CALLED(maphist); 619 620 /* 621 * kernel_object already has plenty of references, leave it alone. 622 */ 623 624 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) 625 return; 626 627 uobj->uo_refs++; /* bump! */ 628 UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)", 629 uobj, uobj->uo_refs,0,0); 630 } 631 632 633 /* 634 * uao_detach: drop a reference to an aobj 635 * 636 * => aobj must be unlocked 637 * => just lock it and call the locked version 638 */ 639 void 640 uao_detach(uobj) 641 struct uvm_object *uobj; 642 { 643 simple_lock(&uobj->vmobjlock); 644 uao_detach_locked(uobj); 645 } 646 647 648 /* 649 * uao_detach_locked: drop a reference to an aobj 650 * 651 * => aobj must be locked, and is unlocked (or freed) upon return. 652 * this needs to be separate from the normal routine 653 * since sometimes we need to detach from an aobj when 654 * it's already locked. 655 */ 656 void 657 uao_detach_locked(uobj) 658 struct uvm_object *uobj; 659 { 660 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 661 struct vm_page *pg; 662 boolean_t busybody; 663 UVMHIST_FUNC("uao_detach"); UVMHIST_CALLED(maphist); 664 665 /* 666 * detaching from kernel_object is a noop. 667 */ 668 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) { 669 simple_unlock(&uobj->vmobjlock); 670 return; 671 } 672 673 UVMHIST_LOG(maphist," (uobj=0x%x) ref=%d", uobj,uobj->uo_refs,0,0); 674 uobj->uo_refs--; /* drop ref! */ 675 if (uobj->uo_refs) { /* still more refs? */ 676 simple_unlock(&uobj->vmobjlock); 677 UVMHIST_LOG(maphist, "<- done (rc>0)", 0,0,0,0); 678 return; 679 } 680 681 /* 682 * remove the aobj from the global list. 683 */ 684 simple_lock(&uao_list_lock); 685 LIST_REMOVE(aobj, u_list); 686 simple_unlock(&uao_list_lock); 687 688 /* 689 * free all the pages that aren't PG_BUSY, 690 * mark for release any that are. 691 */ 692 busybody = FALSE; 693 for (pg = TAILQ_FIRST(&uobj->memq); 694 pg != NULL; 695 pg = TAILQ_NEXT(pg, listq)) { 696 if (pg->flags & PG_BUSY) { 697 pg->flags |= PG_RELEASED; 698 busybody = TRUE; 699 continue; 700 } 701 702 /* zap the mappings, free the swap slot, free the page */ 703 pmap_page_protect(pg, VM_PROT_NONE); 704 uao_dropswap(&aobj->u_obj, pg->offset >> PAGE_SHIFT); 705 uvm_lock_pageq(); 706 uvm_pagefree(pg); 707 uvm_unlock_pageq(); 708 } 709 710 /* 711 * if we found any busy pages, we're done for now. 712 * mark the aobj for death, releasepg will finish up for us. 713 */ 714 if (busybody) { 715 aobj->u_flags |= UAO_FLAG_KILLME; 716 simple_unlock(&aobj->u_obj.vmobjlock); 717 return; 718 } 719 720 /* 721 * finally, free the rest. 722 */ 723 uao_free(aobj); 724 } 725 726 /* 727 * uao_flush: "flush" pages out of a uvm object 728 * 729 * => object should be locked by caller. we may _unlock_ the object 730 * if (and only if) we need to clean a page (PGO_CLEANIT). 731 * XXXJRT Currently, however, we don't. In the case of cleaning 732 * XXXJRT a page, we simply just deactivate it. Should probably 733 * XXXJRT handle this better, in the future (although "flushing" 734 * XXXJRT anonymous memory isn't terribly important). 735 * => if PGO_CLEANIT is not set, then we will neither unlock the object 736 * or block. 737 * => if PGO_ALLPAGE is set, then all pages in the object are valid targets 738 * for flushing. 739 * => NOTE: we rely on the fact that the object's memq is a TAILQ and 740 * that new pages are inserted on the tail end of the list. thus, 741 * we can make a complete pass through the object in one go by starting 742 * at the head and working towards the tail (new pages are put in 743 * front of us). 744 * => NOTE: we are allowed to lock the page queues, so the caller 745 * must not be holding the lock on them [e.g. pagedaemon had 746 * better not call us with the queues locked] 747 * => we return TRUE unless we encountered some sort of I/O error 748 * XXXJRT currently never happens, as we never directly initiate 749 * XXXJRT I/O 750 * 751 * comment on "cleaning" object and PG_BUSY pages: 752 * this routine is holding the lock on the object. the only time 753 * that is can run into a PG_BUSY page that it does not own is if 754 * some other process has started I/O on the page (e.g. either 755 * a pagein or a pageout). if the PG_BUSY page is being paged 756 * in, then it can not be dirty (!PG_CLEAN) because no one has 757 * had a change to modify it yet. if the PG_BUSY page is being 758 * paged out then it means that someone else has already started 759 * cleaning the page for us (how nice!). in this case, if we 760 * have syncio specified, then after we make our pass through the 761 * object we need to wait for the other PG_BUSY pages to clear 762 * off (i.e. we need to do an iosync). also note that once a 763 * page is PG_BUSY is must stary in its object until it is un-busyed. 764 * XXXJRT We never actually do this, as we are "flushing" anonymous 765 * XXXJRT memory, which doesn't have persistent backing store. 766 * 767 * note on page traversal: 768 * we can traverse the pages in an object either by going down the 769 * linked list in "uobj->memq", or we can go over the address range 770 * by page doing hash table lookups for each address. depending 771 * on how many pages are in the object it may be cheaper to do one 772 * or the other. we set "by_list" to true if we are using memq. 773 * if the cost of a hash lookup was equal to the cost of the list 774 * traversal we could compare the number of pages in the start->stop 775 * range to the total number of pages in the object. however, it 776 * seems that a hash table lookup is more expensive than the linked 777 * list traversal, so we multiply the number of pages in the 778 * start->stop range by a penalty which we define below. 779 */ 780 781 #define UAO_HASH_PENALTY 4 /* XXX: a guess */ 782 783 boolean_t 784 uao_flush(uobj, start, stop, flags) 785 struct uvm_object *uobj; 786 voff_t start, stop; 787 int flags; 788 { 789 struct uvm_aobj *aobj = (struct uvm_aobj *) uobj; 790 struct vm_page *pp, *ppnext; 791 boolean_t retval, by_list; 792 voff_t curoff; 793 UVMHIST_FUNC("uao_flush"); UVMHIST_CALLED(maphist); 794 795 curoff = 0; /* XXX: shut up gcc */ 796 797 retval = TRUE; /* default to success */ 798 799 if (flags & PGO_ALLPAGES) { 800 start = 0; 801 stop = aobj->u_pages << PAGE_SHIFT; 802 by_list = TRUE; /* always go by the list */ 803 } else { 804 start = trunc_page(start); 805 stop = round_page(stop); 806 if (stop > (aobj->u_pages << PAGE_SHIFT)) { 807 printf("uao_flush: strange, got an out of range " 808 "flush (fixed)\n"); 809 stop = aobj->u_pages << PAGE_SHIFT; 810 } 811 by_list = (uobj->uo_npages <= 812 ((stop - start) >> PAGE_SHIFT) * UAO_HASH_PENALTY); 813 } 814 815 UVMHIST_LOG(maphist, 816 " flush start=0x%lx, stop=0x%x, by_list=%d, flags=0x%x", 817 start, stop, by_list, flags); 818 819 /* 820 * Don't need to do any work here if we're not freeing 821 * or deactivating pages. 822 */ 823 if ((flags & (PGO_DEACTIVATE|PGO_FREE)) == 0) { 824 UVMHIST_LOG(maphist, 825 "<- done (no work to do)",0,0,0,0); 826 return (retval); 827 } 828 829 /* 830 * now do it. note: we must update ppnext in the body of loop or we 831 * will get stuck. we need to use ppnext because we may free "pp" 832 * before doing the next loop. 833 */ 834 835 if (by_list) { 836 pp = uobj->memq.tqh_first; 837 } else { 838 curoff = start; 839 pp = uvm_pagelookup(uobj, curoff); 840 } 841 842 ppnext = NULL; /* XXX: shut up gcc */ 843 uvm_lock_pageq(); /* page queues locked */ 844 845 /* locked: both page queues and uobj */ 846 for ( ; (by_list && pp != NULL) || 847 (!by_list && curoff < stop) ; pp = ppnext) { 848 if (by_list) { 849 ppnext = TAILQ_NEXT(pp, listq); 850 851 /* range check */ 852 if (pp->offset < start || pp->offset >= stop) 853 continue; 854 } else { 855 curoff += PAGE_SIZE; 856 if (curoff < stop) 857 ppnext = uvm_pagelookup(uobj, curoff); 858 859 /* null check */ 860 if (pp == NULL) 861 continue; 862 } 863 864 switch (flags & (PGO_CLEANIT|PGO_FREE|PGO_DEACTIVATE)) { 865 /* 866 * XXX In these first 3 cases, we always just 867 * XXX deactivate the page. We may want to 868 * XXX handle the different cases more specifically 869 * XXX in the future. 870 */ 871 case PGO_CLEANIT|PGO_FREE: 872 case PGO_CLEANIT|PGO_DEACTIVATE: 873 case PGO_DEACTIVATE: 874 deactivate_it: 875 /* skip the page if it's loaned or wired */ 876 if (pp->loan_count != 0 || 877 pp->wire_count != 0) 878 continue; 879 880 #ifdef UBC 881 /* ...and deactivate the page. */ 882 pmap_clear_reference(pp); 883 #else 884 /* zap all mappings for the page. */ 885 pmap_page_protect(pp, VM_PROT_NONE); 886 887 /* ...and deactivate the page. */ 888 #endif 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 } 926 927 uvm_unlock_pageq(); 928 929 UVMHIST_LOG(maphist, 930 "<- done, rv=%d",retval,0,0,0); 931 return (retval); 932 } 933 934 /* 935 * uao_get: fetch me a page 936 * 937 * we have three cases: 938 * 1: page is resident -> just return the page. 939 * 2: page is zero-fill -> allocate a new page and zero it. 940 * 3: page is swapped out -> fetch the page from swap. 941 * 942 * cases 1 and 2 can be handled with PGO_LOCKED, case 3 cannot. 943 * so, if the "center" page hits case 3 (or any page, with PGO_ALLPAGES), 944 * then we will need to return VM_PAGER_UNLOCK. 945 * 946 * => prefer map unlocked (not required) 947 * => object must be locked! we will _unlock_ it before starting any I/O. 948 * => flags: PGO_ALLPAGES: get all of the pages 949 * PGO_LOCKED: fault data structures are locked 950 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 951 * => NOTE: caller must check for released pages!! 952 */ 953 static int 954 uao_get(uobj, offset, pps, npagesp, centeridx, access_type, advice, flags) 955 struct uvm_object *uobj; 956 voff_t offset; 957 struct vm_page **pps; 958 int *npagesp; 959 int centeridx, advice, flags; 960 vm_prot_t access_type; 961 { 962 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 963 voff_t current_offset; 964 vm_page_t ptmp; 965 int lcv, gotpages, maxpages, swslot, rv, pageidx; 966 boolean_t done; 967 UVMHIST_FUNC("uao_get"); UVMHIST_CALLED(pdhist); 968 969 UVMHIST_LOG(pdhist, "aobj=%p offset=%d, flags=%d", 970 aobj, offset, flags,0); 971 972 /* 973 * get number of pages 974 */ 975 maxpages = *npagesp; 976 977 /* 978 * step 1: handled the case where fault data structures are locked. 979 */ 980 981 if (flags & PGO_LOCKED) { 982 /* 983 * step 1a: get pages that are already resident. only do 984 * this if the data structures are locked (i.e. the first 985 * time through). 986 */ 987 988 done = TRUE; /* be optimistic */ 989 gotpages = 0; /* # of pages we got so far */ 990 991 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 992 lcv++, current_offset += PAGE_SIZE) { 993 /* do we care about this page? if not, skip it */ 994 if (pps[lcv] == PGO_DONTCARE) 995 continue; 996 997 ptmp = uvm_pagelookup(uobj, current_offset); 998 999 /* 1000 * if page is new, attempt to allocate the page, 1001 * zero-fill'd. 1002 */ 1003 if (ptmp == NULL && uao_find_swslot(aobj, 1004 current_offset >> PAGE_SHIFT) == 0) { 1005 ptmp = uvm_pagealloc(uobj, current_offset, 1006 NULL, UVM_PGA_ZERO); 1007 if (ptmp) { 1008 /* new page */ 1009 ptmp->flags &= ~(PG_BUSY|PG_FAKE); 1010 ptmp->pqflags |= PQ_AOBJ; 1011 UVM_PAGE_OWN(ptmp, NULL); 1012 } 1013 } 1014 1015 /* 1016 * to be useful must get a non-busy, non-released page 1017 */ 1018 if (ptmp == NULL || 1019 (ptmp->flags & (PG_BUSY|PG_RELEASED)) != 0) { 1020 if (lcv == centeridx || 1021 (flags & PGO_ALLPAGES) != 0) 1022 /* need to do a wait or I/O! */ 1023 done = FALSE; 1024 continue; 1025 } 1026 1027 /* 1028 * useful page: busy/lock it and plug it in our 1029 * result array 1030 */ 1031 /* caller must un-busy this page */ 1032 ptmp->flags |= PG_BUSY; 1033 UVM_PAGE_OWN(ptmp, "uao_get1"); 1034 pps[lcv] = ptmp; 1035 gotpages++; 1036 1037 } /* "for" lcv loop */ 1038 1039 /* 1040 * step 1b: now we've either done everything needed or we 1041 * to unlock and do some waiting or I/O. 1042 */ 1043 1044 UVMHIST_LOG(pdhist, "<- done (done=%d)", done, 0,0,0); 1045 1046 *npagesp = gotpages; 1047 if (done) 1048 /* bingo! */ 1049 return(VM_PAGER_OK); 1050 else 1051 /* EEK! Need to unlock and I/O */ 1052 return(VM_PAGER_UNLOCK); 1053 } 1054 1055 /* 1056 * step 2: get non-resident or busy pages. 1057 * object is locked. data structures are unlocked. 1058 */ 1059 1060 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 1061 lcv++, current_offset += PAGE_SIZE) { 1062 1063 /* 1064 * - skip over pages we've already gotten or don't want 1065 * - skip over pages we don't _have_ to get 1066 */ 1067 1068 if (pps[lcv] != NULL || 1069 (lcv != centeridx && (flags & PGO_ALLPAGES) == 0)) 1070 continue; 1071 1072 pageidx = current_offset >> PAGE_SHIFT; 1073 1074 /* 1075 * we have yet to locate the current page (pps[lcv]). we 1076 * first look for a page that is already at the current offset. 1077 * if we find a page, we check to see if it is busy or 1078 * released. if that is the case, then we sleep on the page 1079 * until it is no longer busy or released and repeat the lookup. 1080 * if the page we found is neither busy nor released, then we 1081 * busy it (so we own it) and plug it into pps[lcv]. this 1082 * 'break's the following while loop and indicates we are 1083 * ready to move on to the next page in the "lcv" loop above. 1084 * 1085 * if we exit the while loop with pps[lcv] still set to NULL, 1086 * then it means that we allocated a new busy/fake/clean page 1087 * ptmp in the object and we need to do I/O to fill in the data. 1088 */ 1089 1090 /* top of "pps" while loop */ 1091 while (pps[lcv] == NULL) { 1092 /* look for a resident page */ 1093 ptmp = uvm_pagelookup(uobj, current_offset); 1094 1095 /* not resident? allocate one now (if we can) */ 1096 if (ptmp == NULL) { 1097 1098 ptmp = uvm_pagealloc(uobj, current_offset, 1099 NULL, 0); 1100 1101 /* out of RAM? */ 1102 if (ptmp == NULL) { 1103 simple_unlock(&uobj->vmobjlock); 1104 UVMHIST_LOG(pdhist, 1105 "sleeping, ptmp == NULL\n",0,0,0,0); 1106 uvm_wait("uao_getpage"); 1107 simple_lock(&uobj->vmobjlock); 1108 /* goto top of pps while loop */ 1109 continue; 1110 } 1111 1112 /* 1113 * safe with PQ's unlocked: because we just 1114 * alloc'd the page 1115 */ 1116 ptmp->pqflags |= PQ_AOBJ; 1117 1118 /* 1119 * got new page ready for I/O. break pps while 1120 * loop. pps[lcv] is still NULL. 1121 */ 1122 break; 1123 } 1124 1125 /* page is there, see if we need to wait on it */ 1126 if ((ptmp->flags & (PG_BUSY|PG_RELEASED)) != 0) { 1127 ptmp->flags |= PG_WANTED; 1128 UVMHIST_LOG(pdhist, 1129 "sleeping, ptmp->flags 0x%x\n", 1130 ptmp->flags,0,0,0); 1131 UVM_UNLOCK_AND_WAIT(ptmp, &uobj->vmobjlock, 1132 FALSE, "uao_get", 0); 1133 simple_lock(&uobj->vmobjlock); 1134 continue; /* goto top of pps while loop */ 1135 } 1136 1137 /* 1138 * if we get here then the page has become resident and 1139 * unbusy between steps 1 and 2. we busy it now (so we 1140 * own it) and set pps[lcv] (so that we exit the while 1141 * loop). 1142 */ 1143 /* we own it, caller must un-busy */ 1144 ptmp->flags |= PG_BUSY; 1145 UVM_PAGE_OWN(ptmp, "uao_get2"); 1146 pps[lcv] = ptmp; 1147 } 1148 1149 /* 1150 * if we own the valid page at the correct offset, pps[lcv] will 1151 * point to it. nothing more to do except go to the next page. 1152 */ 1153 if (pps[lcv]) 1154 continue; /* next lcv */ 1155 1156 /* 1157 * we have a "fake/busy/clean" page that we just allocated. 1158 * do the needed "i/o", either reading from swap or zeroing. 1159 */ 1160 swslot = uao_find_swslot(aobj, pageidx); 1161 1162 /* 1163 * just zero the page if there's nothing in swap. 1164 */ 1165 if (swslot == 0) 1166 { 1167 /* 1168 * page hasn't existed before, just zero it. 1169 */ 1170 uvm_pagezero(ptmp); 1171 } else { 1172 UVMHIST_LOG(pdhist, "pagein from swslot %d", 1173 swslot, 0,0,0); 1174 1175 /* 1176 * page in the swapped-out page. 1177 * unlock object for i/o, relock when done. 1178 */ 1179 simple_unlock(&uobj->vmobjlock); 1180 rv = uvm_swap_get(ptmp, swslot, PGO_SYNCIO); 1181 simple_lock(&uobj->vmobjlock); 1182 1183 /* 1184 * I/O done. check for errors. 1185 */ 1186 if (rv != VM_PAGER_OK) 1187 { 1188 UVMHIST_LOG(pdhist, "<- done (error=%d)", 1189 rv,0,0,0); 1190 if (ptmp->flags & PG_WANTED) 1191 wakeup(ptmp); 1192 1193 /* 1194 * remove the swap slot from the aobj 1195 * and mark the aobj as having no real slot. 1196 * don't free the swap slot, thus preventing 1197 * it from being used again. 1198 */ 1199 swslot = uao_set_swslot(&aobj->u_obj, pageidx, 1200 SWSLOT_BAD); 1201 uvm_swap_markbad(swslot, 1); 1202 1203 ptmp->flags &= ~(PG_WANTED|PG_BUSY); 1204 UVM_PAGE_OWN(ptmp, NULL); 1205 uvm_lock_pageq(); 1206 uvm_pagefree(ptmp); 1207 uvm_unlock_pageq(); 1208 1209 simple_unlock(&uobj->vmobjlock); 1210 return (rv); 1211 } 1212 } 1213 1214 /* 1215 * we got the page! clear the fake flag (indicates valid 1216 * data now in page) and plug into our result array. note 1217 * that page is still busy. 1218 * 1219 * it is the callers job to: 1220 * => check if the page is released 1221 * => unbusy the page 1222 * => activate the page 1223 */ 1224 1225 ptmp->flags &= ~PG_FAKE; /* data is valid ... */ 1226 pmap_clear_modify(ptmp); /* ... and clean */ 1227 pps[lcv] = ptmp; 1228 1229 } /* lcv loop */ 1230 1231 /* 1232 * finally, unlock object and return. 1233 */ 1234 1235 simple_unlock(&uobj->vmobjlock); 1236 UVMHIST_LOG(pdhist, "<- done (OK)",0,0,0,0); 1237 return(VM_PAGER_OK); 1238 } 1239 1240 /* 1241 * uao_releasepg: handle released page in an aobj 1242 * 1243 * => "pg" is a PG_BUSY [caller owns it], PG_RELEASED page that we need 1244 * to dispose of. 1245 * => caller must handle PG_WANTED case 1246 * => called with page's object locked, pageq's unlocked 1247 * => returns TRUE if page's object is still alive, FALSE if we 1248 * killed the page's object. if we return TRUE, then we 1249 * return with the object locked. 1250 * => if (nextpgp != NULL) => we return the next page on the queue, and return 1251 * with the page queues locked [for pagedaemon] 1252 * => if (nextpgp == NULL) => we return with page queues unlocked [normal case] 1253 * => we kill the aobj if it is not referenced and we are suppose to 1254 * kill it ("KILLME"). 1255 */ 1256 static boolean_t 1257 uao_releasepg(pg, nextpgp) 1258 struct vm_page *pg; 1259 struct vm_page **nextpgp; /* OUT */ 1260 { 1261 struct uvm_aobj *aobj = (struct uvm_aobj *) pg->uobject; 1262 1263 KASSERT(pg->flags & PG_RELEASED); 1264 1265 /* 1266 * dispose of the page [caller handles PG_WANTED] and swap slot. 1267 */ 1268 pmap_page_protect(pg, VM_PROT_NONE); 1269 uao_dropswap(&aobj->u_obj, pg->offset >> PAGE_SHIFT); 1270 uvm_lock_pageq(); 1271 if (nextpgp) 1272 *nextpgp = TAILQ_NEXT(pg, pageq); /* next page for daemon */ 1273 uvm_pagefree(pg); 1274 if (!nextpgp) 1275 uvm_unlock_pageq(); /* keep locked for daemon */ 1276 1277 /* 1278 * if we're not killing the object, we're done. 1279 */ 1280 if ((aobj->u_flags & UAO_FLAG_KILLME) == 0) 1281 return TRUE; 1282 KASSERT(aobj->u_obj.uo_refs == 0); 1283 1284 /* 1285 * if there are still pages in the object, we're done for now. 1286 */ 1287 if (aobj->u_obj.uo_npages != 0) 1288 return TRUE; 1289 1290 KASSERT(TAILQ_EMPTY(&aobj->u_obj.memq)); 1291 1292 /* 1293 * finally, free the rest. 1294 */ 1295 uao_free(aobj); 1296 1297 return FALSE; 1298 } 1299 1300 1301 /* 1302 * uao_dropswap: release any swap resources from this aobj page. 1303 * 1304 * => aobj must be locked or have a reference count of 0. 1305 */ 1306 1307 void 1308 uao_dropswap(uobj, pageidx) 1309 struct uvm_object *uobj; 1310 int pageidx; 1311 { 1312 int slot; 1313 1314 slot = uao_set_swslot(uobj, pageidx, 0); 1315 if (slot) { 1316 uvm_swap_free(slot, 1); 1317 } 1318 } 1319 1320 1321 /* 1322 * page in every page in every aobj that is paged-out to a range of swslots. 1323 * 1324 * => nothing should be locked. 1325 * => returns TRUE if pagein was aborted due to lack of memory. 1326 */ 1327 boolean_t 1328 uao_swap_off(startslot, endslot) 1329 int startslot, endslot; 1330 { 1331 struct uvm_aobj *aobj, *nextaobj; 1332 1333 /* 1334 * walk the list of all aobjs. 1335 */ 1336 1337 restart: 1338 simple_lock(&uao_list_lock); 1339 1340 for (aobj = LIST_FIRST(&uao_list); 1341 aobj != NULL; 1342 aobj = nextaobj) { 1343 boolean_t rv; 1344 1345 /* 1346 * try to get the object lock, 1347 * start all over if we fail. 1348 * most of the time we'll get the aobj lock, 1349 * so this should be a rare case. 1350 */ 1351 if (!simple_lock_try(&aobj->u_obj.vmobjlock)) { 1352 simple_unlock(&uao_list_lock); 1353 goto restart; 1354 } 1355 1356 /* 1357 * add a ref to the aobj so it doesn't disappear 1358 * while we're working. 1359 */ 1360 uao_reference_locked(&aobj->u_obj); 1361 1362 /* 1363 * now it's safe to unlock the uao list. 1364 */ 1365 simple_unlock(&uao_list_lock); 1366 1367 /* 1368 * page in any pages in the swslot range. 1369 * if there's an error, abort and return the error. 1370 */ 1371 rv = uao_pagein(aobj, startslot, endslot); 1372 if (rv) { 1373 uao_detach_locked(&aobj->u_obj); 1374 return rv; 1375 } 1376 1377 /* 1378 * we're done with this aobj. 1379 * relock the list and drop our ref on the aobj. 1380 */ 1381 simple_lock(&uao_list_lock); 1382 nextaobj = LIST_NEXT(aobj, u_list); 1383 uao_detach_locked(&aobj->u_obj); 1384 } 1385 1386 /* 1387 * done with traversal, unlock the list 1388 */ 1389 simple_unlock(&uao_list_lock); 1390 return FALSE; 1391 } 1392 1393 1394 /* 1395 * page in any pages from aobj in the given range. 1396 * 1397 * => aobj must be locked and is returned locked. 1398 * => returns TRUE if pagein was aborted due to lack of memory. 1399 */ 1400 static boolean_t 1401 uao_pagein(aobj, startslot, endslot) 1402 struct uvm_aobj *aobj; 1403 int startslot, endslot; 1404 { 1405 boolean_t rv; 1406 1407 if (UAO_USES_SWHASH(aobj)) { 1408 struct uao_swhash_elt *elt; 1409 int bucket; 1410 1411 restart: 1412 for (bucket = aobj->u_swhashmask; bucket >= 0; bucket--) { 1413 for (elt = LIST_FIRST(&aobj->u_swhash[bucket]); 1414 elt != NULL; 1415 elt = LIST_NEXT(elt, list)) { 1416 int i; 1417 1418 for (i = 0; i < UAO_SWHASH_CLUSTER_SIZE; i++) { 1419 int slot = elt->slots[i]; 1420 1421 /* 1422 * if the slot isn't in range, skip it. 1423 */ 1424 if (slot < startslot || 1425 slot >= endslot) { 1426 continue; 1427 } 1428 1429 /* 1430 * process the page, 1431 * the start over on this object 1432 * since the swhash elt 1433 * may have been freed. 1434 */ 1435 rv = uao_pagein_page(aobj, 1436 UAO_SWHASH_ELT_PAGEIDX_BASE(elt) + i); 1437 if (rv) { 1438 return rv; 1439 } 1440 goto restart; 1441 } 1442 } 1443 } 1444 } else { 1445 int i; 1446 1447 for (i = 0; i < aobj->u_pages; i++) { 1448 int slot = aobj->u_swslots[i]; 1449 1450 /* 1451 * if the slot isn't in range, skip it 1452 */ 1453 if (slot < startslot || slot >= endslot) { 1454 continue; 1455 } 1456 1457 /* 1458 * process the page. 1459 */ 1460 rv = uao_pagein_page(aobj, i); 1461 if (rv) { 1462 return rv; 1463 } 1464 } 1465 } 1466 1467 return FALSE; 1468 } 1469 1470 /* 1471 * page in a page from an aobj. used for swap_off. 1472 * returns TRUE if pagein was aborted due to lack of memory. 1473 * 1474 * => aobj must be locked and is returned locked. 1475 */ 1476 static boolean_t 1477 uao_pagein_page(aobj, pageidx) 1478 struct uvm_aobj *aobj; 1479 int pageidx; 1480 { 1481 struct vm_page *pg; 1482 int rv, slot, npages; 1483 1484 pg = NULL; 1485 npages = 1; 1486 /* locked: aobj */ 1487 rv = uao_get(&aobj->u_obj, pageidx << PAGE_SHIFT, 1488 &pg, &npages, 0, VM_PROT_READ|VM_PROT_WRITE, 0, 0); 1489 /* unlocked: aobj */ 1490 1491 /* 1492 * relock and finish up. 1493 */ 1494 simple_lock(&aobj->u_obj.vmobjlock); 1495 1496 switch (rv) { 1497 case VM_PAGER_OK: 1498 break; 1499 1500 case VM_PAGER_ERROR: 1501 case VM_PAGER_REFAULT: 1502 /* 1503 * nothing more to do on errors. 1504 * VM_PAGER_REFAULT can only mean that the anon was freed, 1505 * so again there's nothing to do. 1506 */ 1507 return FALSE; 1508 1509 } 1510 KASSERT((pg->flags & PG_RELEASED) == 0); 1511 1512 /* 1513 * ok, we've got the page now. 1514 * mark it as dirty, clear its swslot and un-busy it. 1515 */ 1516 slot = uao_set_swslot(&aobj->u_obj, pageidx, 0); 1517 uvm_swap_free(slot, 1); 1518 pg->flags &= ~(PG_BUSY|PG_CLEAN|PG_FAKE); 1519 UVM_PAGE_OWN(pg, NULL); 1520 1521 /* 1522 * deactivate the page (to put it on a page queue). 1523 */ 1524 pmap_clear_reference(pg); 1525 #ifndef UBC 1526 pmap_page_protect(pg, VM_PROT_NONE); 1527 #endif 1528 uvm_lock_pageq(); 1529 uvm_pagedeactivate(pg); 1530 uvm_unlock_pageq(); 1531 1532 return FALSE; 1533 } 1534