1 /* $NetBSD: uvm_aobj.c,v 1.31 2000/05/19 04:34:45 thorpej 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/pool.h> 54 #include <sys/kernel.h> 55 56 #include <vm/vm.h> 57 #include <vm/vm_page.h> 58 #include <vm/vm_kern.h> 59 60 #include <uvm/uvm.h> 61 62 /* 63 * an aobj manages anonymous-memory backed uvm_objects. in addition 64 * to keeping the list of resident pages, it also keeps a list of 65 * allocated swap blocks. depending on the size of the aobj this list 66 * of allocated swap blocks is either stored in an array (small objects) 67 * or in a hash table (large objects). 68 */ 69 70 /* 71 * local structures 72 */ 73 74 /* 75 * for hash tables, we break the address space of the aobj into blocks 76 * of UAO_SWHASH_CLUSTER_SIZE pages. we require the cluster size to 77 * be a power of two. 78 */ 79 80 #define UAO_SWHASH_CLUSTER_SHIFT 4 81 #define UAO_SWHASH_CLUSTER_SIZE (1 << UAO_SWHASH_CLUSTER_SHIFT) 82 83 /* get the "tag" for this page index */ 84 #define UAO_SWHASH_ELT_TAG(PAGEIDX) \ 85 ((PAGEIDX) >> UAO_SWHASH_CLUSTER_SHIFT) 86 87 /* given an ELT and a page index, find the swap slot */ 88 #define UAO_SWHASH_ELT_PAGESLOT(ELT, PAGEIDX) \ 89 ((ELT)->slots[(PAGEIDX) & (UAO_SWHASH_CLUSTER_SIZE - 1)]) 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 #define UAO_SWHASH_HASH(AOBJ, PAGEIDX) \ 99 (&(AOBJ)->u_swhash[(((PAGEIDX) >> UAO_SWHASH_CLUSTER_SHIFT) \ 100 & (AOBJ)->u_swhashmask)]) 101 102 /* 103 * the swhash threshhold determines if we will use an array or a 104 * hash table to store the list of allocated swap blocks. 105 */ 106 107 #define UAO_SWHASH_THRESHOLD (UAO_SWHASH_CLUSTER_SIZE * 4) 108 #define UAO_USES_SWHASH(AOBJ) \ 109 ((AOBJ)->u_pages > UAO_SWHASH_THRESHOLD) /* use hash? */ 110 111 /* 112 * the number of buckets in a swhash, with an upper bound 113 */ 114 #define UAO_SWHASH_MAXBUCKETS 256 115 #define UAO_SWHASH_BUCKETS(AOBJ) \ 116 (min((AOBJ)->u_pages >> UAO_SWHASH_CLUSTER_SHIFT, \ 117 UAO_SWHASH_MAXBUCKETS)) 118 119 120 /* 121 * uao_swhash_elt: when a hash table is being used, this structure defines 122 * the format of an entry in the bucket list. 123 */ 124 125 struct uao_swhash_elt { 126 LIST_ENTRY(uao_swhash_elt) list; /* the hash list */ 127 voff_t tag; /* our 'tag' */ 128 int count; /* our number of active slots */ 129 int slots[UAO_SWHASH_CLUSTER_SIZE]; /* the slots */ 130 }; 131 132 /* 133 * uao_swhash: the swap hash table structure 134 */ 135 136 LIST_HEAD(uao_swhash, uao_swhash_elt); 137 138 /* 139 * uao_swhash_elt_pool: pool of uao_swhash_elt structures 140 */ 141 142 struct pool uao_swhash_elt_pool; 143 144 /* 145 * uvm_aobj: the actual anon-backed uvm_object 146 * 147 * => the uvm_object is at the top of the structure, this allows 148 * (struct uvm_device *) == (struct uvm_object *) 149 * => only one of u_swslots and u_swhash is used in any given aobj 150 */ 151 152 struct uvm_aobj { 153 struct uvm_object u_obj; /* has: lock, pgops, memq, #pages, #refs */ 154 int u_pages; /* number of pages in entire object */ 155 int u_flags; /* the flags (see uvm_aobj.h) */ 156 int *u_swslots; /* array of offset->swapslot mappings */ 157 /* 158 * hashtable of offset->swapslot mappings 159 * (u_swhash is an array of bucket heads) 160 */ 161 struct uao_swhash *u_swhash; 162 u_long u_swhashmask; /* mask for hashtable */ 163 LIST_ENTRY(uvm_aobj) u_list; /* global list of aobjs */ 164 }; 165 166 /* 167 * uvm_aobj_pool: pool of uvm_aobj structures 168 */ 169 170 struct pool uvm_aobj_pool; 171 172 /* 173 * local functions 174 */ 175 176 static struct uao_swhash_elt *uao_find_swhash_elt __P((struct uvm_aobj *, 177 int, boolean_t)); 178 static int uao_find_swslot __P((struct uvm_aobj *, int)); 179 static boolean_t uao_flush __P((struct uvm_object *, 180 voff_t, voff_t, int)); 181 static void uao_free __P((struct uvm_aobj *)); 182 static int uao_get __P((struct uvm_object *, voff_t, 183 vm_page_t *, int *, int, 184 vm_prot_t, int, int)); 185 static boolean_t uao_releasepg __P((struct vm_page *, 186 struct vm_page **)); 187 static boolean_t uao_pagein __P((struct uvm_aobj *, int, int)); 188 static boolean_t uao_pagein_page __P((struct uvm_aobj *, int)); 189 190 191 192 /* 193 * aobj_pager 194 * 195 * note that some functions (e.g. put) are handled elsewhere 196 */ 197 198 struct uvm_pagerops aobj_pager = { 199 NULL, /* init */ 200 uao_reference, /* reference */ 201 uao_detach, /* detach */ 202 NULL, /* fault */ 203 uao_flush, /* flush */ 204 uao_get, /* get */ 205 NULL, /* asyncget */ 206 NULL, /* put (done by pagedaemon) */ 207 NULL, /* cluster */ 208 NULL, /* mk_pcluster */ 209 NULL, /* aiodone */ 210 uao_releasepg /* releasepg */ 211 }; 212 213 /* 214 * uao_list: global list of active aobjs, locked by uao_list_lock 215 */ 216 217 static LIST_HEAD(aobjlist, uvm_aobj) uao_list; 218 static simple_lock_data_t uao_list_lock; 219 220 221 /* 222 * functions 223 */ 224 225 /* 226 * hash table/array related functions 227 */ 228 229 /* 230 * uao_find_swhash_elt: find (or create) a hash table entry for a page 231 * offset. 232 * 233 * => the object should be locked by the caller 234 */ 235 236 static struct uao_swhash_elt * 237 uao_find_swhash_elt(aobj, pageidx, create) 238 struct uvm_aobj *aobj; 239 int pageidx; 240 boolean_t create; 241 { 242 struct uao_swhash *swhash; 243 struct uao_swhash_elt *elt; 244 voff_t page_tag; 245 246 swhash = UAO_SWHASH_HASH(aobj, pageidx); /* first hash to get bucket */ 247 page_tag = UAO_SWHASH_ELT_TAG(pageidx); /* tag to search for */ 248 249 /* 250 * now search the bucket for the requested tag 251 */ 252 for (elt = swhash->lh_first; elt != NULL; elt = elt->list.le_next) { 253 if (elt->tag == page_tag) 254 return(elt); 255 } 256 257 /* fail now if we are not allowed to create a new entry in the bucket */ 258 if (!create) 259 return NULL; 260 261 262 /* 263 * allocate a new entry for the bucket and init/insert it in 264 */ 265 elt = pool_get(&uao_swhash_elt_pool, PR_WAITOK); 266 LIST_INSERT_HEAD(swhash, elt, list); 267 elt->tag = page_tag; 268 elt->count = 0; 269 memset(elt->slots, 0, sizeof(elt->slots)); 270 271 return(elt); 272 } 273 274 /* 275 * uao_find_swslot: find the swap slot number for an aobj/pageidx 276 * 277 * => object must be locked by caller 278 */ 279 __inline static int 280 uao_find_swslot(aobj, pageidx) 281 struct uvm_aobj *aobj; 282 int pageidx; 283 { 284 285 /* 286 * if noswap flag is set, then we never return a slot 287 */ 288 289 if (aobj->u_flags & UAO_FLAG_NOSWAP) 290 return(0); 291 292 /* 293 * if hashing, look in hash table. 294 */ 295 296 if (UAO_USES_SWHASH(aobj)) { 297 struct uao_swhash_elt *elt = 298 uao_find_swhash_elt(aobj, pageidx, FALSE); 299 300 if (elt) 301 return(UAO_SWHASH_ELT_PAGESLOT(elt, pageidx)); 302 else 303 return(0); 304 } 305 306 /* 307 * otherwise, look in the array 308 */ 309 return(aobj->u_swslots[pageidx]); 310 } 311 312 /* 313 * uao_set_swslot: set the swap slot for a page in an aobj. 314 * 315 * => setting a slot to zero frees the slot 316 * => object must be locked by caller 317 */ 318 int 319 uao_set_swslot(uobj, pageidx, slot) 320 struct uvm_object *uobj; 321 int pageidx, slot; 322 { 323 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 324 int oldslot; 325 UVMHIST_FUNC("uao_set_swslot"); UVMHIST_CALLED(pdhist); 326 UVMHIST_LOG(pdhist, "aobj %p pageidx %d slot %d", 327 aobj, pageidx, slot, 0); 328 329 /* 330 * if noswap flag is set, then we can't set a slot 331 */ 332 333 if (aobj->u_flags & UAO_FLAG_NOSWAP) { 334 335 if (slot == 0) 336 return(0); /* a clear is ok */ 337 338 /* but a set is not */ 339 printf("uao_set_swslot: uobj = %p\n", uobj); 340 panic("uao_set_swslot: attempt to set a slot on a NOSWAP object"); 341 } 342 343 /* 344 * are we using a hash table? if so, add it in the hash. 345 */ 346 347 if (UAO_USES_SWHASH(aobj)) { 348 /* 349 * Avoid allocating an entry just to free it again if 350 * the page had not swap slot in the first place, and 351 * we are freeing. 352 */ 353 struct uao_swhash_elt *elt = 354 uao_find_swhash_elt(aobj, pageidx, slot ? TRUE : FALSE); 355 if (elt == NULL) { 356 #ifdef DIAGNOSTIC 357 if (slot) 358 panic("uao_set_swslot: didn't create elt"); 359 #endif 360 return (0); 361 } 362 363 oldslot = UAO_SWHASH_ELT_PAGESLOT(elt, pageidx); 364 UAO_SWHASH_ELT_PAGESLOT(elt, pageidx) = slot; 365 366 /* 367 * now adjust the elt's reference counter and free it if we've 368 * dropped it to zero. 369 */ 370 371 /* an allocation? */ 372 if (slot) { 373 if (oldslot == 0) 374 elt->count++; 375 } else { /* freeing slot ... */ 376 if (oldslot) /* to be safe */ 377 elt->count--; 378 379 if (elt->count == 0) { 380 LIST_REMOVE(elt, list); 381 pool_put(&uao_swhash_elt_pool, elt); 382 } 383 } 384 385 } else { 386 /* we are using an array */ 387 oldslot = aobj->u_swslots[pageidx]; 388 aobj->u_swslots[pageidx] = slot; 389 } 390 return (oldslot); 391 } 392 393 /* 394 * end of hash/array functions 395 */ 396 397 /* 398 * uao_free: free all resources held by an aobj, and then free the aobj 399 * 400 * => the aobj should be dead 401 */ 402 static void 403 uao_free(aobj) 404 struct uvm_aobj *aobj; 405 { 406 407 simple_unlock(&aobj->u_obj.vmobjlock); 408 409 if (UAO_USES_SWHASH(aobj)) { 410 int i, hashbuckets = aobj->u_swhashmask + 1; 411 412 /* 413 * free the swslots from each hash bucket, 414 * then the hash bucket, and finally the hash table itself. 415 */ 416 for (i = 0; i < hashbuckets; i++) { 417 struct uao_swhash_elt *elt, *next; 418 419 for (elt = LIST_FIRST(&aobj->u_swhash[i]); 420 elt != NULL; 421 elt = next) { 422 int j; 423 424 for (j = 0; j < UAO_SWHASH_CLUSTER_SIZE; j++) { 425 int slot = elt->slots[j]; 426 427 if (slot) { 428 uvm_swap_free(slot, 1); 429 430 /* 431 * this page is no longer 432 * only in swap. 433 */ 434 simple_lock(&uvm.swap_data_lock); 435 uvmexp.swpgonly--; 436 simple_unlock(&uvm.swap_data_lock); 437 } 438 } 439 440 next = LIST_NEXT(elt, list); 441 pool_put(&uao_swhash_elt_pool, elt); 442 } 443 } 444 FREE(aobj->u_swhash, M_UVMAOBJ); 445 } else { 446 int i; 447 448 /* 449 * free the array 450 */ 451 452 for (i = 0; i < aobj->u_pages; i++) { 453 int slot = aobj->u_swslots[i]; 454 455 if (slot) { 456 uvm_swap_free(slot, 1); 457 458 /* this page is no longer only in swap. */ 459 simple_lock(&uvm.swap_data_lock); 460 uvmexp.swpgonly--; 461 simple_unlock(&uvm.swap_data_lock); 462 } 463 } 464 FREE(aobj->u_swslots, M_UVMAOBJ); 465 } 466 467 /* 468 * finally free the aobj itself 469 */ 470 pool_put(&uvm_aobj_pool, aobj); 471 } 472 473 /* 474 * pager functions 475 */ 476 477 /* 478 * uao_create: create an aobj of the given size and return its uvm_object. 479 * 480 * => for normal use, flags are always zero 481 * => for the kernel object, the flags are: 482 * UAO_FLAG_KERNOBJ - allocate the kernel object (can only happen once) 483 * UAO_FLAG_KERNSWAP - enable swapping of kernel object (" ") 484 */ 485 struct uvm_object * 486 uao_create(size, flags) 487 vsize_t size; 488 int flags; 489 { 490 static struct uvm_aobj kernel_object_store; /* home of kernel_object */ 491 static int kobj_alloced = 0; /* not allocated yet */ 492 int pages = round_page(size) >> PAGE_SHIFT; 493 struct uvm_aobj *aobj; 494 495 /* 496 * malloc a new aobj unless we are asked for the kernel object 497 */ 498 if (flags & UAO_FLAG_KERNOBJ) { /* want kernel object? */ 499 if (kobj_alloced) 500 panic("uao_create: kernel object already allocated"); 501 502 aobj = &kernel_object_store; 503 aobj->u_pages = pages; 504 aobj->u_flags = UAO_FLAG_NOSWAP; /* no swap to start */ 505 /* we are special, we never die */ 506 aobj->u_obj.uo_refs = UVM_OBJ_KERN; 507 kobj_alloced = UAO_FLAG_KERNOBJ; 508 } else if (flags & UAO_FLAG_KERNSWAP) { 509 aobj = &kernel_object_store; 510 if (kobj_alloced != UAO_FLAG_KERNOBJ) 511 panic("uao_create: asked to enable swap on kernel object"); 512 kobj_alloced = UAO_FLAG_KERNSWAP; 513 } else { /* normal object */ 514 aobj = pool_get(&uvm_aobj_pool, PR_WAITOK); 515 aobj->u_pages = pages; 516 aobj->u_flags = 0; /* normal object */ 517 aobj->u_obj.uo_refs = 1; /* start with 1 reference */ 518 } 519 520 /* 521 * allocate hash/array if necessary 522 * 523 * note: in the KERNSWAP case no need to worry about locking since 524 * we are still booting we should be the only thread around. 525 */ 526 if (flags == 0 || (flags & UAO_FLAG_KERNSWAP) != 0) { 527 int mflags = (flags & UAO_FLAG_KERNSWAP) != 0 ? 528 M_NOWAIT : M_WAITOK; 529 530 /* allocate hash table or array depending on object size */ 531 if (UAO_USES_SWHASH(aobj)) { 532 aobj->u_swhash = hashinit(UAO_SWHASH_BUCKETS(aobj), 533 M_UVMAOBJ, mflags, &aobj->u_swhashmask); 534 if (aobj->u_swhash == NULL) 535 panic("uao_create: hashinit swhash failed"); 536 } else { 537 MALLOC(aobj->u_swslots, int *, pages * sizeof(int), 538 M_UVMAOBJ, mflags); 539 if (aobj->u_swslots == NULL) 540 panic("uao_create: malloc swslots failed"); 541 memset(aobj->u_swslots, 0, pages * sizeof(int)); 542 } 543 544 if (flags) { 545 aobj->u_flags &= ~UAO_FLAG_NOSWAP; /* clear noswap */ 546 return(&aobj->u_obj); 547 /* done! */ 548 } 549 } 550 551 /* 552 * init aobj fields 553 */ 554 simple_lock_init(&aobj->u_obj.vmobjlock); 555 aobj->u_obj.pgops = &aobj_pager; 556 TAILQ_INIT(&aobj->u_obj.memq); 557 aobj->u_obj.uo_npages = 0; 558 559 /* 560 * now that aobj is ready, add it to the global list 561 */ 562 simple_lock(&uao_list_lock); 563 LIST_INSERT_HEAD(&uao_list, aobj, u_list); 564 simple_unlock(&uao_list_lock); 565 566 /* 567 * done! 568 */ 569 return(&aobj->u_obj); 570 } 571 572 573 574 /* 575 * uao_init: set up aobj pager subsystem 576 * 577 * => called at boot time from uvm_pager_init() 578 */ 579 void 580 uao_init() 581 { 582 static int uao_initialized; 583 584 if (uao_initialized) 585 return; 586 uao_initialized = TRUE; 587 588 LIST_INIT(&uao_list); 589 simple_lock_init(&uao_list_lock); 590 591 /* 592 * NOTE: Pages fror this pool must not come from a pageable 593 * kernel map! 594 */ 595 pool_init(&uao_swhash_elt_pool, sizeof(struct uao_swhash_elt), 596 0, 0, 0, "uaoeltpl", 0, NULL, NULL, M_UVMAOBJ); 597 598 pool_init(&uvm_aobj_pool, sizeof(struct uvm_aobj), 0, 0, 0, 599 "aobjpl", 0, 600 pool_page_alloc_nointr, pool_page_free_nointr, M_UVMAOBJ); 601 } 602 603 /* 604 * uao_reference: add a ref to an aobj 605 * 606 * => aobj must be unlocked 607 * => just lock it and call the locked version 608 */ 609 void 610 uao_reference(uobj) 611 struct uvm_object *uobj; 612 { 613 simple_lock(&uobj->vmobjlock); 614 uao_reference_locked(uobj); 615 simple_unlock(&uobj->vmobjlock); 616 } 617 618 /* 619 * uao_reference_locked: add a ref to an aobj that is already locked 620 * 621 * => aobj must be locked 622 * this needs to be separate from the normal routine 623 * since sometimes we need to add a reference to an aobj when 624 * it's already locked. 625 */ 626 void 627 uao_reference_locked(uobj) 628 struct uvm_object *uobj; 629 { 630 UVMHIST_FUNC("uao_reference"); UVMHIST_CALLED(maphist); 631 632 /* 633 * kernel_object already has plenty of references, leave it alone. 634 */ 635 636 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) 637 return; 638 639 uobj->uo_refs++; /* bump! */ 640 UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)", 641 uobj, uobj->uo_refs,0,0); 642 } 643 644 645 /* 646 * uao_detach: drop a reference to an aobj 647 * 648 * => aobj must be unlocked 649 * => just lock it and call the locked version 650 */ 651 void 652 uao_detach(uobj) 653 struct uvm_object *uobj; 654 { 655 simple_lock(&uobj->vmobjlock); 656 uao_detach_locked(uobj); 657 } 658 659 660 /* 661 * uao_detach_locked: drop a reference to an aobj 662 * 663 * => aobj must be locked, and is unlocked (or freed) upon return. 664 * this needs to be separate from the normal routine 665 * since sometimes we need to detach from an aobj when 666 * it's already locked. 667 */ 668 void 669 uao_detach_locked(uobj) 670 struct uvm_object *uobj; 671 { 672 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 673 struct vm_page *pg; 674 boolean_t busybody; 675 UVMHIST_FUNC("uao_detach"); UVMHIST_CALLED(maphist); 676 677 /* 678 * detaching from kernel_object is a noop. 679 */ 680 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) { 681 simple_unlock(&uobj->vmobjlock); 682 return; 683 } 684 685 UVMHIST_LOG(maphist," (uobj=0x%x) ref=%d", uobj,uobj->uo_refs,0,0); 686 uobj->uo_refs--; /* drop ref! */ 687 if (uobj->uo_refs) { /* still more refs? */ 688 simple_unlock(&uobj->vmobjlock); 689 UVMHIST_LOG(maphist, "<- done (rc>0)", 0,0,0,0); 690 return; 691 } 692 693 /* 694 * remove the aobj from the global list. 695 */ 696 simple_lock(&uao_list_lock); 697 LIST_REMOVE(aobj, u_list); 698 simple_unlock(&uao_list_lock); 699 700 /* 701 * free all the pages that aren't PG_BUSY, 702 * mark for release any that are. 703 */ 704 busybody = FALSE; 705 for (pg = TAILQ_FIRST(&uobj->memq); 706 pg != NULL; 707 pg = TAILQ_NEXT(pg, listq)) { 708 if (pg->flags & PG_BUSY) { 709 pg->flags |= PG_RELEASED; 710 busybody = TRUE; 711 continue; 712 } 713 714 /* zap the mappings, free the swap slot, free the page */ 715 pmap_page_protect(pg, VM_PROT_NONE); 716 uao_dropswap(&aobj->u_obj, pg->offset >> PAGE_SHIFT); 717 uvm_lock_pageq(); 718 uvm_pagefree(pg); 719 uvm_unlock_pageq(); 720 } 721 722 /* 723 * if we found any busy pages, we're done for now. 724 * mark the aobj for death, releasepg will finish up for us. 725 */ 726 if (busybody) { 727 aobj->u_flags |= UAO_FLAG_KILLME; 728 simple_unlock(&aobj->u_obj.vmobjlock); 729 return; 730 } 731 732 /* 733 * finally, free the rest. 734 */ 735 uao_free(aobj); 736 } 737 738 /* 739 * uao_flush: "flush" pages out of a uvm object 740 * 741 * => object should be locked by caller. we may _unlock_ the object 742 * if (and only if) we need to clean a page (PGO_CLEANIT). 743 * XXXJRT Currently, however, we don't. In the case of cleaning 744 * XXXJRT a page, we simply just deactivate it. Should probably 745 * XXXJRT handle this better, in the future (although "flushing" 746 * XXXJRT anonymous memory isn't terribly important). 747 * => if PGO_CLEANIT is not set, then we will neither unlock the object 748 * or block. 749 * => if PGO_ALLPAGE is set, then all pages in the object are valid targets 750 * for flushing. 751 * => NOTE: we rely on the fact that the object's memq is a TAILQ and 752 * that new pages are inserted on the tail end of the list. thus, 753 * we can make a complete pass through the object in one go by starting 754 * at the head and working towards the tail (new pages are put in 755 * front of us). 756 * => NOTE: we are allowed to lock the page queues, so the caller 757 * must not be holding the lock on them [e.g. pagedaemon had 758 * better not call us with the queues locked] 759 * => we return TRUE unless we encountered some sort of I/O error 760 * XXXJRT currently never happens, as we never directly initiate 761 * XXXJRT I/O 762 * 763 * comment on "cleaning" object and PG_BUSY pages: 764 * this routine is holding the lock on the object. the only time 765 * that is can run into a PG_BUSY page that it does not own is if 766 * some other process has started I/O on the page (e.g. either 767 * a pagein or a pageout). if the PG_BUSY page is being paged 768 * in, then it can not be dirty (!PG_CLEAN) because no one has 769 * had a change to modify it yet. if the PG_BUSY page is being 770 * paged out then it means that someone else has already started 771 * cleaning the page for us (how nice!). in this case, if we 772 * have syncio specified, then after we make our pass through the 773 * object we need to wait for the other PG_BUSY pages to clear 774 * off (i.e. we need to do an iosync). also note that once a 775 * page is PG_BUSY is must stary in its object until it is un-busyed. 776 * XXXJRT We never actually do this, as we are "flushing" anonymous 777 * XXXJRT memory, which doesn't have persistent backing store. 778 * 779 * note on page traversal: 780 * we can traverse the pages in an object either by going down the 781 * linked list in "uobj->memq", or we can go over the address range 782 * by page doing hash table lookups for each address. depending 783 * on how many pages are in the object it may be cheaper to do one 784 * or the other. we set "by_list" to true if we are using memq. 785 * if the cost of a hash lookup was equal to the cost of the list 786 * traversal we could compare the number of pages in the start->stop 787 * range to the total number of pages in the object. however, it 788 * seems that a hash table lookup is more expensive than the linked 789 * list traversal, so we multiply the number of pages in the 790 * start->stop range by a penalty which we define below. 791 */ 792 793 #define UAO_HASH_PENALTY 4 /* XXX: a guess */ 794 795 boolean_t 796 uao_flush(uobj, start, stop, flags) 797 struct uvm_object *uobj; 798 voff_t start, stop; 799 int flags; 800 { 801 struct uvm_aobj *aobj = (struct uvm_aobj *) uobj; 802 struct vm_page *pp, *ppnext; 803 boolean_t retval, by_list; 804 voff_t curoff; 805 UVMHIST_FUNC("uao_flush"); UVMHIST_CALLED(maphist); 806 807 curoff = 0; /* XXX: shut up gcc */ 808 809 retval = TRUE; /* default to success */ 810 811 if (flags & PGO_ALLPAGES) { 812 start = 0; 813 stop = aobj->u_pages << PAGE_SHIFT; 814 by_list = TRUE; /* always go by the list */ 815 } else { 816 start = trunc_page(start); 817 stop = round_page(stop); 818 if (stop > (aobj->u_pages << PAGE_SHIFT)) { 819 printf("uao_flush: strange, got an out of range " 820 "flush (fixed)\n"); 821 stop = aobj->u_pages << PAGE_SHIFT; 822 } 823 by_list = (uobj->uo_npages <= 824 ((stop - start) >> PAGE_SHIFT) * UAO_HASH_PENALTY); 825 } 826 827 UVMHIST_LOG(maphist, 828 " flush start=0x%lx, stop=0x%x, by_list=%d, flags=0x%x", 829 start, stop, by_list, flags); 830 831 /* 832 * Don't need to do any work here if we're not freeing 833 * or deactivating pages. 834 */ 835 if ((flags & (PGO_DEACTIVATE|PGO_FREE)) == 0) { 836 UVMHIST_LOG(maphist, 837 "<- done (no work to do)",0,0,0,0); 838 return (retval); 839 } 840 841 /* 842 * now do it. note: we must update ppnext in the body of loop or we 843 * will get stuck. we need to use ppnext because we may free "pp" 844 * before doing the next loop. 845 */ 846 847 if (by_list) { 848 pp = uobj->memq.tqh_first; 849 } else { 850 curoff = start; 851 pp = uvm_pagelookup(uobj, curoff); 852 } 853 854 ppnext = NULL; /* XXX: shut up gcc */ 855 uvm_lock_pageq(); /* page queues locked */ 856 857 /* locked: both page queues and uobj */ 858 for ( ; (by_list && pp != NULL) || 859 (!by_list && curoff < stop) ; pp = ppnext) { 860 if (by_list) { 861 ppnext = pp->listq.tqe_next; 862 863 /* range check */ 864 if (pp->offset < start || pp->offset >= stop) 865 continue; 866 } else { 867 curoff += PAGE_SIZE; 868 if (curoff < stop) 869 ppnext = uvm_pagelookup(uobj, curoff); 870 871 /* null check */ 872 if (pp == NULL) 873 continue; 874 } 875 876 switch (flags & (PGO_CLEANIT|PGO_FREE|PGO_DEACTIVATE)) { 877 /* 878 * XXX In these first 3 cases, we always just 879 * XXX deactivate the page. We may want to 880 * XXX handle the different cases more specifically 881 * XXX in the future. 882 */ 883 case PGO_CLEANIT|PGO_FREE: 884 case PGO_CLEANIT|PGO_DEACTIVATE: 885 case PGO_DEACTIVATE: 886 deactivate_it: 887 /* skip the page if it's loaned or wired */ 888 if (pp->loan_count != 0 || 889 pp->wire_count != 0) 890 continue; 891 892 /* zap all mappings for the page. */ 893 pmap_page_protect(pp, VM_PROT_NONE); 894 895 /* ...and deactivate the page. */ 896 uvm_pagedeactivate(pp); 897 898 continue; 899 900 case PGO_FREE: 901 /* 902 * If there are multiple references to 903 * the object, just deactivate the page. 904 */ 905 if (uobj->uo_refs > 1) 906 goto deactivate_it; 907 908 /* XXX skip the page if it's loaned or wired */ 909 if (pp->loan_count != 0 || 910 pp->wire_count != 0) 911 continue; 912 913 /* 914 * mark the page as released if its busy. 915 */ 916 if (pp->flags & PG_BUSY) { 917 pp->flags |= PG_RELEASED; 918 continue; 919 } 920 921 /* zap all mappings for the page. */ 922 pmap_page_protect(pp, VM_PROT_NONE); 923 924 uao_dropswap(uobj, pp->offset >> PAGE_SHIFT); 925 uvm_pagefree(pp); 926 927 continue; 928 929 default: 930 panic("uao_flush: weird flags"); 931 } 932 #ifdef DIAGNOSTIC 933 panic("uao_flush: unreachable code"); 934 #endif 935 } 936 937 uvm_unlock_pageq(); 938 939 UVMHIST_LOG(maphist, 940 "<- done, rv=%d",retval,0,0,0); 941 return (retval); 942 } 943 944 /* 945 * uao_get: fetch me a page 946 * 947 * we have three cases: 948 * 1: page is resident -> just return the page. 949 * 2: page is zero-fill -> allocate a new page and zero it. 950 * 3: page is swapped out -> fetch the page from swap. 951 * 952 * cases 1 and 2 can be handled with PGO_LOCKED, case 3 cannot. 953 * so, if the "center" page hits case 3 (or any page, with PGO_ALLPAGES), 954 * then we will need to return VM_PAGER_UNLOCK. 955 * 956 * => prefer map unlocked (not required) 957 * => object must be locked! we will _unlock_ it before starting any I/O. 958 * => flags: PGO_ALLPAGES: get all of the pages 959 * PGO_LOCKED: fault data structures are locked 960 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 961 * => NOTE: caller must check for released pages!! 962 */ 963 static int 964 uao_get(uobj, offset, pps, npagesp, centeridx, access_type, advice, flags) 965 struct uvm_object *uobj; 966 voff_t offset; 967 struct vm_page **pps; 968 int *npagesp; 969 int centeridx, advice, flags; 970 vm_prot_t access_type; 971 { 972 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 973 voff_t current_offset; 974 vm_page_t ptmp; 975 int lcv, gotpages, maxpages, swslot, rv, pageidx; 976 boolean_t done; 977 UVMHIST_FUNC("uao_get"); UVMHIST_CALLED(pdhist); 978 979 UVMHIST_LOG(pdhist, "aobj=%p offset=%d, flags=%d", 980 aobj, offset, flags,0); 981 982 /* 983 * get number of pages 984 */ 985 maxpages = *npagesp; 986 987 /* 988 * step 1: handled the case where fault data structures are locked. 989 */ 990 991 if (flags & PGO_LOCKED) { 992 /* 993 * step 1a: get pages that are already resident. only do 994 * this if the data structures are locked (i.e. the first 995 * time through). 996 */ 997 998 done = TRUE; /* be optimistic */ 999 gotpages = 0; /* # of pages we got so far */ 1000 1001 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 1002 lcv++, current_offset += PAGE_SIZE) { 1003 /* do we care about this page? if not, skip it */ 1004 if (pps[lcv] == PGO_DONTCARE) 1005 continue; 1006 1007 ptmp = uvm_pagelookup(uobj, current_offset); 1008 1009 /* 1010 * if page is new, attempt to allocate the page, 1011 * zero-fill'd. 1012 */ 1013 if (ptmp == NULL && uao_find_swslot(aobj, 1014 current_offset >> PAGE_SHIFT) == 0) { 1015 ptmp = uvm_pagealloc(uobj, current_offset, 1016 NULL, UVM_PGA_ZERO); 1017 if (ptmp) { 1018 /* new page */ 1019 ptmp->flags &= ~(PG_BUSY|PG_FAKE); 1020 ptmp->pqflags |= PQ_AOBJ; 1021 UVM_PAGE_OWN(ptmp, NULL); 1022 } 1023 } 1024 1025 /* 1026 * to be useful must get a non-busy, non-released page 1027 */ 1028 if (ptmp == NULL || 1029 (ptmp->flags & (PG_BUSY|PG_RELEASED)) != 0) { 1030 if (lcv == centeridx || 1031 (flags & PGO_ALLPAGES) != 0) 1032 /* need to do a wait or I/O! */ 1033 done = FALSE; 1034 continue; 1035 } 1036 1037 /* 1038 * useful page: busy/lock it and plug it in our 1039 * result array 1040 */ 1041 /* caller must un-busy this page */ 1042 ptmp->flags |= PG_BUSY; 1043 UVM_PAGE_OWN(ptmp, "uao_get1"); 1044 pps[lcv] = ptmp; 1045 gotpages++; 1046 1047 } /* "for" lcv loop */ 1048 1049 /* 1050 * step 1b: now we've either done everything needed or we 1051 * to unlock and do some waiting or I/O. 1052 */ 1053 1054 UVMHIST_LOG(pdhist, "<- done (done=%d)", done, 0,0,0); 1055 1056 *npagesp = gotpages; 1057 if (done) 1058 /* bingo! */ 1059 return(VM_PAGER_OK); 1060 else 1061 /* EEK! Need to unlock and I/O */ 1062 return(VM_PAGER_UNLOCK); 1063 } 1064 1065 /* 1066 * step 2: get non-resident or busy pages. 1067 * object is locked. data structures are unlocked. 1068 */ 1069 1070 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 1071 lcv++, current_offset += PAGE_SIZE) { 1072 1073 /* 1074 * - skip over pages we've already gotten or don't want 1075 * - skip over pages we don't _have_ to get 1076 */ 1077 1078 if (pps[lcv] != NULL || 1079 (lcv != centeridx && (flags & PGO_ALLPAGES) == 0)) 1080 continue; 1081 1082 pageidx = current_offset >> PAGE_SHIFT; 1083 1084 /* 1085 * we have yet to locate the current page (pps[lcv]). we 1086 * first look for a page that is already at the current offset. 1087 * if we find a page, we check to see if it is busy or 1088 * released. if that is the case, then we sleep on the page 1089 * until it is no longer busy or released and repeat the lookup. 1090 * if the page we found is neither busy nor released, then we 1091 * busy it (so we own it) and plug it into pps[lcv]. this 1092 * 'break's the following while loop and indicates we are 1093 * ready to move on to the next page in the "lcv" loop above. 1094 * 1095 * if we exit the while loop with pps[lcv] still set to NULL, 1096 * then it means that we allocated a new busy/fake/clean page 1097 * ptmp in the object and we need to do I/O to fill in the data. 1098 */ 1099 1100 /* top of "pps" while loop */ 1101 while (pps[lcv] == NULL) { 1102 /* look for a resident page */ 1103 ptmp = uvm_pagelookup(uobj, current_offset); 1104 1105 /* not resident? allocate one now (if we can) */ 1106 if (ptmp == NULL) { 1107 1108 ptmp = uvm_pagealloc(uobj, current_offset, 1109 NULL, 0); 1110 1111 /* out of RAM? */ 1112 if (ptmp == NULL) { 1113 simple_unlock(&uobj->vmobjlock); 1114 UVMHIST_LOG(pdhist, 1115 "sleeping, ptmp == NULL\n",0,0,0,0); 1116 uvm_wait("uao_getpage"); 1117 simple_lock(&uobj->vmobjlock); 1118 /* goto top of pps while loop */ 1119 continue; 1120 } 1121 1122 /* 1123 * safe with PQ's unlocked: because we just 1124 * alloc'd the page 1125 */ 1126 ptmp->pqflags |= PQ_AOBJ; 1127 1128 /* 1129 * got new page ready for I/O. break pps while 1130 * loop. pps[lcv] is still NULL. 1131 */ 1132 break; 1133 } 1134 1135 /* page is there, see if we need to wait on it */ 1136 if ((ptmp->flags & (PG_BUSY|PG_RELEASED)) != 0) { 1137 ptmp->flags |= PG_WANTED; 1138 UVMHIST_LOG(pdhist, 1139 "sleeping, ptmp->flags 0x%x\n", 1140 ptmp->flags,0,0,0); 1141 UVM_UNLOCK_AND_WAIT(ptmp, &uobj->vmobjlock, 1142 FALSE, "uao_get", 0); 1143 simple_lock(&uobj->vmobjlock); 1144 continue; /* goto top of pps while loop */ 1145 } 1146 1147 /* 1148 * if we get here then the page has become resident and 1149 * unbusy between steps 1 and 2. we busy it now (so we 1150 * own it) and set pps[lcv] (so that we exit the while 1151 * loop). 1152 */ 1153 /* we own it, caller must un-busy */ 1154 ptmp->flags |= PG_BUSY; 1155 UVM_PAGE_OWN(ptmp, "uao_get2"); 1156 pps[lcv] = ptmp; 1157 } 1158 1159 /* 1160 * if we own the valid page at the correct offset, pps[lcv] will 1161 * point to it. nothing more to do except go to the next page. 1162 */ 1163 if (pps[lcv]) 1164 continue; /* next lcv */ 1165 1166 /* 1167 * we have a "fake/busy/clean" page that we just allocated. 1168 * do the needed "i/o", either reading from swap or zeroing. 1169 */ 1170 swslot = uao_find_swslot(aobj, pageidx); 1171 1172 /* 1173 * just zero the page if there's nothing in swap. 1174 */ 1175 if (swslot == 0) 1176 { 1177 /* 1178 * page hasn't existed before, just zero it. 1179 */ 1180 uvm_pagezero(ptmp); 1181 } else { 1182 UVMHIST_LOG(pdhist, "pagein from swslot %d", 1183 swslot, 0,0,0); 1184 1185 /* 1186 * page in the swapped-out page. 1187 * unlock object for i/o, relock when done. 1188 */ 1189 simple_unlock(&uobj->vmobjlock); 1190 rv = uvm_swap_get(ptmp, swslot, PGO_SYNCIO); 1191 simple_lock(&uobj->vmobjlock); 1192 1193 /* 1194 * I/O done. check for errors. 1195 */ 1196 if (rv != VM_PAGER_OK) 1197 { 1198 UVMHIST_LOG(pdhist, "<- done (error=%d)", 1199 rv,0,0,0); 1200 if (ptmp->flags & PG_WANTED) 1201 wakeup(ptmp); 1202 1203 /* 1204 * remove the swap slot from the aobj 1205 * and mark the aobj as having no real slot. 1206 * don't free the swap slot, thus preventing 1207 * it from being used again. 1208 */ 1209 swslot = uao_set_swslot(&aobj->u_obj, pageidx, 1210 SWSLOT_BAD); 1211 uvm_swap_markbad(swslot, 1); 1212 1213 ptmp->flags &= ~(PG_WANTED|PG_BUSY); 1214 UVM_PAGE_OWN(ptmp, NULL); 1215 uvm_lock_pageq(); 1216 uvm_pagefree(ptmp); 1217 uvm_unlock_pageq(); 1218 1219 simple_unlock(&uobj->vmobjlock); 1220 return (rv); 1221 } 1222 } 1223 1224 /* 1225 * we got the page! clear the fake flag (indicates valid 1226 * data now in page) and plug into our result array. note 1227 * that page is still busy. 1228 * 1229 * it is the callers job to: 1230 * => check if the page is released 1231 * => unbusy the page 1232 * => activate the page 1233 */ 1234 1235 ptmp->flags &= ~PG_FAKE; /* data is valid ... */ 1236 pmap_clear_modify(ptmp); /* ... and clean */ 1237 pps[lcv] = ptmp; 1238 1239 } /* lcv loop */ 1240 1241 /* 1242 * finally, unlock object and return. 1243 */ 1244 1245 simple_unlock(&uobj->vmobjlock); 1246 UVMHIST_LOG(pdhist, "<- done (OK)",0,0,0,0); 1247 return(VM_PAGER_OK); 1248 } 1249 1250 /* 1251 * uao_releasepg: handle released page in an aobj 1252 * 1253 * => "pg" is a PG_BUSY [caller owns it], PG_RELEASED page that we need 1254 * to dispose of. 1255 * => caller must handle PG_WANTED case 1256 * => called with page's object locked, pageq's unlocked 1257 * => returns TRUE if page's object is still alive, FALSE if we 1258 * killed the page's object. if we return TRUE, then we 1259 * return with the object locked. 1260 * => if (nextpgp != NULL) => we return pageq.tqe_next here, and return 1261 * with the page queues locked [for pagedaemon] 1262 * => if (nextpgp == NULL) => we return with page queues unlocked [normal case] 1263 * => we kill the aobj if it is not referenced and we are suppose to 1264 * kill it ("KILLME"). 1265 */ 1266 static boolean_t 1267 uao_releasepg(pg, nextpgp) 1268 struct vm_page *pg; 1269 struct vm_page **nextpgp; /* OUT */ 1270 { 1271 struct uvm_aobj *aobj = (struct uvm_aobj *) pg->uobject; 1272 1273 #ifdef DIAGNOSTIC 1274 if ((pg->flags & PG_RELEASED) == 0) 1275 panic("uao_releasepg: page not released!"); 1276 #endif 1277 1278 /* 1279 * dispose of the page [caller handles PG_WANTED] and swap slot. 1280 */ 1281 pmap_page_protect(pg, VM_PROT_NONE); 1282 uao_dropswap(&aobj->u_obj, pg->offset >> PAGE_SHIFT); 1283 uvm_lock_pageq(); 1284 if (nextpgp) 1285 *nextpgp = pg->pageq.tqe_next; /* next page for daemon */ 1286 uvm_pagefree(pg); 1287 if (!nextpgp) 1288 uvm_unlock_pageq(); /* keep locked for daemon */ 1289 1290 /* 1291 * if we're not killing the object, we're done. 1292 */ 1293 if ((aobj->u_flags & UAO_FLAG_KILLME) == 0) 1294 return TRUE; 1295 1296 #ifdef DIAGNOSTIC 1297 if (aobj->u_obj.uo_refs) 1298 panic("uvm_km_releasepg: kill flag set on referenced object!"); 1299 #endif 1300 1301 /* 1302 * if there are still pages in the object, we're done for now. 1303 */ 1304 if (aobj->u_obj.uo_npages != 0) 1305 return TRUE; 1306 1307 #ifdef DIAGNOSTIC 1308 if (TAILQ_FIRST(&aobj->u_obj.memq)) 1309 panic("uvn_releasepg: pages in object with npages == 0"); 1310 #endif 1311 1312 /* 1313 * finally, free the rest. 1314 */ 1315 uao_free(aobj); 1316 1317 return FALSE; 1318 } 1319 1320 1321 /* 1322 * uao_dropswap: release any swap resources from this aobj page. 1323 * 1324 * => aobj must be locked or have a reference count of 0. 1325 */ 1326 1327 void 1328 uao_dropswap(uobj, pageidx) 1329 struct uvm_object *uobj; 1330 int pageidx; 1331 { 1332 int slot; 1333 1334 slot = uao_set_swslot(uobj, pageidx, 0); 1335 if (slot) { 1336 uvm_swap_free(slot, 1); 1337 } 1338 } 1339 1340 1341 /* 1342 * page in every page in every aobj that is paged-out to a range of swslots. 1343 * 1344 * => nothing should be locked. 1345 * => returns TRUE if pagein was aborted due to lack of memory. 1346 */ 1347 boolean_t 1348 uao_swap_off(startslot, endslot) 1349 int startslot, endslot; 1350 { 1351 struct uvm_aobj *aobj, *nextaobj; 1352 1353 /* 1354 * walk the list of all aobjs. 1355 */ 1356 1357 restart: 1358 simple_lock(&uao_list_lock); 1359 1360 for (aobj = LIST_FIRST(&uao_list); 1361 aobj != NULL; 1362 aobj = nextaobj) { 1363 boolean_t rv; 1364 1365 /* 1366 * try to get the object lock, 1367 * start all over if we fail. 1368 * most of the time we'll get the aobj lock, 1369 * so this should be a rare case. 1370 */ 1371 if (!simple_lock_try(&aobj->u_obj.vmobjlock)) { 1372 simple_unlock(&uao_list_lock); 1373 goto restart; 1374 } 1375 1376 /* 1377 * add a ref to the aobj so it doesn't disappear 1378 * while we're working. 1379 */ 1380 uao_reference_locked(&aobj->u_obj); 1381 1382 /* 1383 * now it's safe to unlock the uao list. 1384 */ 1385 simple_unlock(&uao_list_lock); 1386 1387 /* 1388 * page in any pages in the swslot range. 1389 * if there's an error, abort and return the error. 1390 */ 1391 rv = uao_pagein(aobj, startslot, endslot); 1392 if (rv) { 1393 uao_detach_locked(&aobj->u_obj); 1394 return rv; 1395 } 1396 1397 /* 1398 * we're done with this aobj. 1399 * relock the list and drop our ref on the aobj. 1400 */ 1401 simple_lock(&uao_list_lock); 1402 nextaobj = LIST_NEXT(aobj, u_list); 1403 uao_detach_locked(&aobj->u_obj); 1404 } 1405 1406 /* 1407 * done with traversal, unlock the list 1408 */ 1409 simple_unlock(&uao_list_lock); 1410 return FALSE; 1411 } 1412 1413 1414 /* 1415 * page in any pages from aobj in the given range. 1416 * 1417 * => aobj must be locked and is returned locked. 1418 * => returns TRUE if pagein was aborted due to lack of memory. 1419 */ 1420 static boolean_t 1421 uao_pagein(aobj, startslot, endslot) 1422 struct uvm_aobj *aobj; 1423 int startslot, endslot; 1424 { 1425 boolean_t rv; 1426 1427 if (UAO_USES_SWHASH(aobj)) { 1428 struct uao_swhash_elt *elt; 1429 int bucket; 1430 1431 restart: 1432 for (bucket = aobj->u_swhashmask; bucket >= 0; bucket--) { 1433 for (elt = LIST_FIRST(&aobj->u_swhash[bucket]); 1434 elt != NULL; 1435 elt = LIST_NEXT(elt, list)) { 1436 int i; 1437 1438 for (i = 0; i < UAO_SWHASH_CLUSTER_SIZE; i++) { 1439 int slot = elt->slots[i]; 1440 1441 /* 1442 * if the slot isn't in range, skip it. 1443 */ 1444 if (slot < startslot || 1445 slot >= endslot) { 1446 continue; 1447 } 1448 1449 /* 1450 * process the page, 1451 * the start over on this object 1452 * since the swhash elt 1453 * may have been freed. 1454 */ 1455 rv = uao_pagein_page(aobj, 1456 UAO_SWHASH_ELT_PAGEIDX_BASE(elt) + i); 1457 if (rv) { 1458 return rv; 1459 } 1460 goto restart; 1461 } 1462 } 1463 } 1464 } else { 1465 int i; 1466 1467 for (i = 0; i < aobj->u_pages; i++) { 1468 int slot = aobj->u_swslots[i]; 1469 1470 /* 1471 * if the slot isn't in range, skip it 1472 */ 1473 if (slot < startslot || slot >= endslot) { 1474 continue; 1475 } 1476 1477 /* 1478 * process the page. 1479 */ 1480 rv = uao_pagein_page(aobj, i); 1481 if (rv) { 1482 return rv; 1483 } 1484 } 1485 } 1486 1487 return FALSE; 1488 } 1489 1490 /* 1491 * page in a page from an aobj. used for swap_off. 1492 * returns TRUE if pagein was aborted due to lack of memory. 1493 * 1494 * => aobj must be locked and is returned locked. 1495 */ 1496 static boolean_t 1497 uao_pagein_page(aobj, pageidx) 1498 struct uvm_aobj *aobj; 1499 int pageidx; 1500 { 1501 struct vm_page *pg; 1502 int rv, slot, npages; 1503 UVMHIST_FUNC("uao_pagein_page"); UVMHIST_CALLED(pdhist); 1504 1505 pg = NULL; 1506 npages = 1; 1507 /* locked: aobj */ 1508 rv = uao_get(&aobj->u_obj, pageidx << PAGE_SHIFT, 1509 &pg, &npages, 0, VM_PROT_READ|VM_PROT_WRITE, 0, 0); 1510 /* unlocked: aobj */ 1511 1512 /* 1513 * relock and finish up. 1514 */ 1515 simple_lock(&aobj->u_obj.vmobjlock); 1516 1517 switch (rv) { 1518 case VM_PAGER_OK: 1519 break; 1520 1521 case VM_PAGER_ERROR: 1522 case VM_PAGER_REFAULT: 1523 /* 1524 * nothing more to do on errors. 1525 * VM_PAGER_REFAULT can only mean that the anon was freed, 1526 * so again there's nothing to do. 1527 */ 1528 return FALSE; 1529 1530 #ifdef DIAGNOSTIC 1531 default: 1532 panic("uao_pagein_page: uao_get -> %d\n", rv); 1533 #endif 1534 } 1535 1536 #ifdef DIAGNOSTIC 1537 /* 1538 * this should never happen, since we have a reference on the aobj. 1539 */ 1540 if (pg->flags & PG_RELEASED) { 1541 panic("uao_pagein_page: found PG_RELEASED page?\n"); 1542 } 1543 #endif 1544 1545 /* 1546 * ok, we've got the page now. 1547 * mark it as dirty, clear its swslot and un-busy it. 1548 */ 1549 slot = uao_set_swslot(&aobj->u_obj, pageidx, 0); 1550 uvm_swap_free(slot, 1); 1551 pg->flags &= ~(PG_BUSY|PG_CLEAN|PG_FAKE); 1552 UVM_PAGE_OWN(pg, NULL); 1553 1554 /* 1555 * deactivate the page (to put it on a page queue). 1556 */ 1557 pmap_clear_reference(pg); 1558 pmap_page_protect(pg, VM_PROT_NONE); 1559 uvm_lock_pageq(); 1560 uvm_pagedeactivate(pg); 1561 uvm_unlock_pageq(); 1562 1563 return FALSE; 1564 } 1565