1 /* $OpenBSD: uvm_aobj.c,v 1.67 2014/07/12 18:44:01 tedu 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 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 * 29 * from: Id: uvm_aobj.c,v 1.1.2.5 1998/02/06 05:14:38 chs Exp 30 */ 31 /* 32 * uvm_aobj.c: anonymous memory uvm_object pager 33 * 34 * author: Chuck Silvers <chuq@chuq.com> 35 * started: Jan-1998 36 * 37 * - design mostly from Chuck Cranor 38 */ 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/proc.h> 43 #include <sys/malloc.h> 44 #include <sys/kernel.h> 45 #include <sys/pool.h> 46 #include <sys/kernel.h> 47 #include <sys/stdint.h> 48 49 #include <uvm/uvm.h> 50 51 /* 52 * an aobj manages anonymous-memory backed uvm_objects. in addition 53 * to keeping the list of resident pages, it also keeps a list of 54 * allocated swap blocks. depending on the size of the aobj this list 55 * of allocated swap blocks is either stored in an array (small objects) 56 * or in a hash table (large objects). 57 */ 58 59 /* 60 * local structures 61 */ 62 63 /* 64 * for hash tables, we break the address space of the aobj into blocks 65 * of UAO_SWHASH_CLUSTER_SIZE pages. we require the cluster size to 66 * be a power of two. 67 */ 68 #define UAO_SWHASH_CLUSTER_SHIFT 4 69 #define UAO_SWHASH_CLUSTER_SIZE (1 << UAO_SWHASH_CLUSTER_SHIFT) 70 71 /* get the "tag" for this page index */ 72 #define UAO_SWHASH_ELT_TAG(PAGEIDX) \ 73 ((PAGEIDX) >> UAO_SWHASH_CLUSTER_SHIFT) 74 75 /* given an ELT and a page index, find the swap slot */ 76 #define UAO_SWHASH_ELT_PAGESLOT_IDX(PAGEIDX) \ 77 ((PAGEIDX) & (UAO_SWHASH_CLUSTER_SIZE - 1)) 78 #define UAO_SWHASH_ELT_PAGESLOT(ELT, PAGEIDX) \ 79 ((ELT)->slots[(PAGEIDX) & (UAO_SWHASH_CLUSTER_SIZE - 1)]) 80 81 /* given an ELT, return its pageidx base */ 82 #define UAO_SWHASH_ELT_PAGEIDX_BASE(ELT) \ 83 ((ELT)->tag << UAO_SWHASH_CLUSTER_SHIFT) 84 85 /* 86 * the swhash hash function 87 */ 88 #define UAO_SWHASH_HASH(AOBJ, PAGEIDX) \ 89 (&(AOBJ)->u_swhash[(((PAGEIDX) >> UAO_SWHASH_CLUSTER_SHIFT) \ 90 & (AOBJ)->u_swhashmask)]) 91 92 /* 93 * the swhash threshold determines if we will use an array or a 94 * hash table to store the list of allocated swap blocks. 95 */ 96 97 #define UAO_SWHASH_THRESHOLD (UAO_SWHASH_CLUSTER_SIZE * 4) 98 99 /* 100 * the number of buckets in a swhash, with an upper bound 101 */ 102 #define UAO_SWHASH_MAXBUCKETS 256 103 #define UAO_SWHASH_BUCKETS(pages) \ 104 (min((pages) >> UAO_SWHASH_CLUSTER_SHIFT, UAO_SWHASH_MAXBUCKETS)) 105 106 107 /* 108 * uao_swhash_elt: when a hash table is being used, this structure defines 109 * the format of an entry in the bucket list. 110 */ 111 struct uao_swhash_elt { 112 LIST_ENTRY(uao_swhash_elt) list; /* the hash list */ 113 voff_t tag; /* our 'tag' */ 114 int count; /* our number of active slots */ 115 int slots[UAO_SWHASH_CLUSTER_SIZE]; /* the slots */ 116 }; 117 118 /* 119 * uao_swhash: the swap hash table structure 120 */ 121 LIST_HEAD(uao_swhash, uao_swhash_elt); 122 123 /* 124 * uao_swhash_elt_pool: pool of uao_swhash_elt structures 125 */ 126 struct pool uao_swhash_elt_pool; 127 128 /* 129 * uvm_aobj: the actual anon-backed uvm_object 130 * 131 * => the uvm_object is at the top of the structure, this allows 132 * (struct uvm_aobj *) == (struct uvm_object *) 133 * => only one of u_swslots and u_swhash is used in any given aobj 134 */ 135 struct uvm_aobj { 136 struct uvm_object u_obj; /* has: pgops, memt, #pages, #refs */ 137 int u_pages; /* number of pages in entire object */ 138 int u_flags; /* the flags (see uvm_aobj.h) */ 139 /* 140 * Either an array or hashtable (array of bucket heads) of 141 * offset -> swapslot mappings for the aobj. 142 */ 143 #define u_swslots u_swap.slot_array 144 #define u_swhash u_swap.slot_hash 145 union swslots { 146 int *slot_array; 147 struct uao_swhash *slot_hash; 148 } u_swap; 149 u_long u_swhashmask; /* mask for hashtable */ 150 LIST_ENTRY(uvm_aobj) u_list; /* global list of aobjs */ 151 }; 152 153 /* 154 * uvm_aobj_pool: pool of uvm_aobj structures 155 */ 156 struct pool uvm_aobj_pool; 157 158 /* 159 * local functions 160 */ 161 static struct uao_swhash_elt *uao_find_swhash_elt(struct uvm_aobj *, int, 162 boolean_t); 163 static int uao_find_swslot(struct uvm_aobj *, int); 164 static boolean_t uao_flush(struct uvm_object *, voff_t, 165 voff_t, int); 166 static void uao_free(struct uvm_aobj *); 167 static int uao_get(struct uvm_object *, voff_t, 168 vm_page_t *, int *, int, vm_prot_t, 169 int, int); 170 static boolean_t uao_pagein(struct uvm_aobj *, int, int); 171 static boolean_t uao_pagein_page(struct uvm_aobj *, int); 172 173 void uao_dropswap_range(struct uvm_object *, voff_t, voff_t); 174 void uao_shrink_flush(struct uvm_object *, int, int); 175 int uao_shrink_hash(struct uvm_object *, int); 176 int uao_shrink_array(struct uvm_object *, int); 177 int uao_shrink_convert(struct uvm_object *, int); 178 179 int uao_grow_hash(struct uvm_object *, int); 180 int uao_grow_array(struct uvm_object *, int); 181 int uao_grow_convert(struct uvm_object *, int); 182 183 /* 184 * aobj_pager 185 * 186 * note that some functions (e.g. put) are handled elsewhere 187 */ 188 struct uvm_pagerops aobj_pager = { 189 NULL, /* init */ 190 uao_reference, /* reference */ 191 uao_detach, /* detach */ 192 NULL, /* fault */ 193 uao_flush, /* flush */ 194 uao_get, /* get */ 195 }; 196 197 /* 198 * uao_list: global list of active aobjs, locked by uao_list_lock 199 * 200 * Lock ordering: generally the locking order is object lock, then list lock. 201 * in the case of swap off we have to iterate over the list, and thus the 202 * ordering is reversed. In that case we must use trylocking to prevent 203 * deadlock. 204 */ 205 static LIST_HEAD(aobjlist, uvm_aobj) uao_list = LIST_HEAD_INITIALIZER(uao_list); 206 static struct mutex uao_list_lock = MUTEX_INITIALIZER(IPL_NONE); 207 208 209 /* 210 * functions 211 */ 212 /* 213 * hash table/array related functions 214 */ 215 /* 216 * uao_find_swhash_elt: find (or create) a hash table entry for a page 217 * offset. 218 */ 219 static struct uao_swhash_elt * 220 uao_find_swhash_elt(struct uvm_aobj *aobj, int pageidx, boolean_t create) 221 { 222 struct uao_swhash *swhash; 223 struct uao_swhash_elt *elt; 224 voff_t page_tag; 225 226 swhash = UAO_SWHASH_HASH(aobj, pageidx); /* first hash to get bucket */ 227 page_tag = UAO_SWHASH_ELT_TAG(pageidx); /* tag to search for */ 228 229 /* now search the bucket for the requested tag */ 230 LIST_FOREACH(elt, swhash, list) { 231 if (elt->tag == page_tag) 232 return(elt); 233 } 234 235 /* fail now if we are not allowed to create a new entry in the bucket */ 236 if (!create) 237 return NULL; 238 239 /* allocate a new entry for the bucket and init/insert it in */ 240 elt = pool_get(&uao_swhash_elt_pool, PR_WAITOK | PR_ZERO); 241 LIST_INSERT_HEAD(swhash, elt, list); 242 elt->tag = page_tag; 243 244 return(elt); 245 } 246 247 /* 248 * uao_find_swslot: find the swap slot number for an aobj/pageidx 249 */ 250 __inline static int 251 uao_find_swslot(struct uvm_aobj *aobj, int pageidx) 252 { 253 254 /* if noswap flag is set, then we never return a slot */ 255 if (aobj->u_flags & UAO_FLAG_NOSWAP) 256 return(0); 257 258 /* if hashing, look in hash table. */ 259 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 260 struct uao_swhash_elt *elt = 261 uao_find_swhash_elt(aobj, pageidx, FALSE); 262 263 if (elt) 264 return(UAO_SWHASH_ELT_PAGESLOT(elt, pageidx)); 265 else 266 return(0); 267 } 268 269 /* otherwise, look in the array */ 270 return(aobj->u_swslots[pageidx]); 271 } 272 273 /* 274 * uao_set_swslot: set the swap slot for a page in an aobj. 275 * 276 * => setting a slot to zero frees the slot 277 */ 278 int 279 uao_set_swslot(struct uvm_object *uobj, int pageidx, int slot) 280 { 281 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 282 int oldslot; 283 284 /* if noswap flag is set, then we can't set a slot */ 285 if (aobj->u_flags & UAO_FLAG_NOSWAP) { 286 if (slot == 0) 287 return(0); /* a clear is ok */ 288 289 /* but a set is not */ 290 printf("uao_set_swslot: uobj = %p\n", uobj); 291 panic("uao_set_swslot: attempt to set a slot" 292 " on a NOSWAP object"); 293 } 294 295 /* are we using a hash table? if so, add it in the hash. */ 296 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 297 /* 298 * Avoid allocating an entry just to free it again if 299 * the page had not swap slot in the first place, and 300 * we are freeing. 301 */ 302 struct uao_swhash_elt *elt = 303 uao_find_swhash_elt(aobj, pageidx, slot ? TRUE : FALSE); 304 if (elt == NULL) { 305 KASSERT(slot == 0); 306 return (0); 307 } 308 309 oldslot = UAO_SWHASH_ELT_PAGESLOT(elt, pageidx); 310 UAO_SWHASH_ELT_PAGESLOT(elt, pageidx) = slot; 311 312 /* 313 * now adjust the elt's reference counter and free it if we've 314 * dropped it to zero. 315 */ 316 /* an allocation? */ 317 if (slot) { 318 if (oldslot == 0) 319 elt->count++; 320 } else { /* freeing slot ... */ 321 if (oldslot) /* to be safe */ 322 elt->count--; 323 324 if (elt->count == 0) { 325 LIST_REMOVE(elt, list); 326 pool_put(&uao_swhash_elt_pool, elt); 327 } 328 } 329 } else { 330 /* we are using an array */ 331 oldslot = aobj->u_swslots[pageidx]; 332 aobj->u_swslots[pageidx] = slot; 333 } 334 return (oldslot); 335 } 336 /* 337 * end of hash/array functions 338 */ 339 340 /* 341 * uao_free: free all resources held by an aobj, and then free the aobj 342 * 343 * => the aobj should be dead 344 */ 345 static void 346 uao_free(struct uvm_aobj *aobj) 347 { 348 349 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 350 int i, hashbuckets = aobj->u_swhashmask + 1; 351 352 /* 353 * free the swslots from each hash bucket, 354 * then the hash bucket, and finally the hash table itself. 355 */ 356 for (i = 0; i < hashbuckets; i++) { 357 struct uao_swhash_elt *elt, *next; 358 359 for (elt = LIST_FIRST(&aobj->u_swhash[i]); 360 elt != NULL; 361 elt = next) { 362 int j; 363 364 for (j = 0; j < UAO_SWHASH_CLUSTER_SIZE; j++) { 365 int slot = elt->slots[j]; 366 367 if (slot == 0) { 368 continue; 369 } 370 uvm_swap_free(slot, 1); 371 /* 372 * this page is no longer 373 * only in swap. 374 */ 375 uvmexp.swpgonly--; 376 } 377 378 next = LIST_NEXT(elt, list); 379 pool_put(&uao_swhash_elt_pool, elt); 380 } 381 } 382 free(aobj->u_swhash, M_UVMAOBJ, 0); 383 } else { 384 int i; 385 386 /* free the array */ 387 for (i = 0; i < aobj->u_pages; i++) { 388 int slot = aobj->u_swslots[i]; 389 390 if (slot) { 391 uvm_swap_free(slot, 1); 392 /* this page is no longer only in swap. */ 393 uvmexp.swpgonly--; 394 } 395 } 396 free(aobj->u_swslots, M_UVMAOBJ, 0); 397 } 398 399 /* finally free the aobj itself */ 400 pool_put(&uvm_aobj_pool, aobj); 401 } 402 403 /* 404 * pager functions 405 */ 406 407 /* 408 * Shrink an aobj to a given number of pages. The procedure is always the same: 409 * assess the necessity of data structure conversion (hash to array), secure 410 * resources, flush pages and drop swap slots. 411 * 412 */ 413 414 void 415 uao_shrink_flush(struct uvm_object *uobj, int startpg, int endpg) 416 { 417 KASSERT(startpg < endpg); 418 KASSERT(uobj->uo_refs == 1); 419 uao_flush(uobj, (voff_t)startpg << PAGE_SHIFT, 420 (voff_t)endpg << PAGE_SHIFT, PGO_FREE); 421 uao_dropswap_range(uobj, startpg, endpg); 422 } 423 424 int 425 uao_shrink_hash(struct uvm_object *uobj, int pages) 426 { 427 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 428 struct uao_swhash *new_swhash; 429 struct uao_swhash_elt *elt; 430 unsigned long new_hashmask; 431 int i; 432 433 KASSERT(aobj->u_pages > UAO_SWHASH_THRESHOLD); 434 435 /* 436 * If the size of the hash table doesn't change, all we need to do is 437 * to adjust the page count. 438 */ 439 if (UAO_SWHASH_BUCKETS(aobj->u_pages) == UAO_SWHASH_BUCKETS(pages)) { 440 uao_shrink_flush(uobj, pages, aobj->u_pages); 441 aobj->u_pages = pages; 442 return 0; 443 } 444 445 new_swhash = hashinit(UAO_SWHASH_BUCKETS(pages), M_UVMAOBJ, 446 M_WAITOK | M_CANFAIL, &new_hashmask); 447 if (new_swhash == NULL) 448 return ENOMEM; 449 450 uao_shrink_flush(uobj, pages, aobj->u_pages); 451 452 /* 453 * Even though the hash table size is changing, the hash of the buckets 454 * we are interested in copying should not change. 455 */ 456 for (i = 0; i < UAO_SWHASH_BUCKETS(aobj->u_pages); i++) { 457 while (LIST_EMPTY(&aobj->u_swhash[i]) == 0) { 458 elt = LIST_FIRST(&aobj->u_swhash[i]); 459 LIST_REMOVE(elt, list); 460 LIST_INSERT_HEAD(&new_swhash[i], elt, list); 461 } 462 } 463 464 free(aobj->u_swhash, M_UVMAOBJ, 0); 465 466 aobj->u_swhash = new_swhash; 467 aobj->u_pages = pages; 468 aobj->u_swhashmask = new_hashmask; 469 470 return 0; 471 } 472 473 int 474 uao_shrink_convert(struct uvm_object *uobj, int pages) 475 { 476 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 477 struct uao_swhash_elt *elt; 478 int i, *new_swslots; 479 480 new_swslots = malloc(pages * sizeof(int), M_UVMAOBJ, 481 M_WAITOK | M_CANFAIL | M_ZERO); 482 if (new_swslots == NULL) 483 return ENOMEM; 484 485 uao_shrink_flush(uobj, pages, aobj->u_pages); 486 487 /* Convert swap slots from hash to array. */ 488 for (i = 0; i < pages; i++) { 489 elt = uao_find_swhash_elt(aobj, i, FALSE); 490 if (elt != NULL) { 491 new_swslots[i] = UAO_SWHASH_ELT_PAGESLOT(elt, i); 492 if (new_swslots[i] != 0) 493 elt->count--; 494 if (elt->count == 0) { 495 LIST_REMOVE(elt, list); 496 pool_put(&uao_swhash_elt_pool, elt); 497 } 498 } 499 } 500 501 free(aobj->u_swhash, M_UVMAOBJ, 0); 502 503 aobj->u_swslots = new_swslots; 504 aobj->u_pages = pages; 505 506 return 0; 507 } 508 509 int 510 uao_shrink_array(struct uvm_object *uobj, int pages) 511 { 512 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 513 int i, *new_swslots; 514 515 new_swslots = malloc(pages * sizeof(int), M_UVMAOBJ, 516 M_WAITOK | M_CANFAIL | M_ZERO); 517 if (new_swslots == NULL) 518 return ENOMEM; 519 520 uao_shrink_flush(uobj, pages, aobj->u_pages); 521 522 for (i = 0; i < pages; i++) 523 new_swslots[i] = aobj->u_swslots[i]; 524 525 free(aobj->u_swslots, M_UVMAOBJ, 0); 526 527 aobj->u_swslots = new_swslots; 528 aobj->u_pages = pages; 529 530 return 0; 531 } 532 533 int 534 uao_shrink(struct uvm_object *uobj, int pages) 535 { 536 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 537 538 KASSERT(pages < aobj->u_pages); 539 540 /* 541 * Distinguish between three possible cases: 542 * 1. aobj uses hash and must be converted to array. 543 * 2. aobj uses array and array size needs to be adjusted. 544 * 3. aobj uses hash and hash size needs to be adjusted. 545 */ 546 if (pages > UAO_SWHASH_THRESHOLD) 547 return uao_shrink_hash(uobj, pages); /* case 3 */ 548 else if (aobj->u_pages > UAO_SWHASH_THRESHOLD) 549 return uao_shrink_convert(uobj, pages); /* case 1 */ 550 else 551 return uao_shrink_array(uobj, pages); /* case 2 */ 552 } 553 554 /* 555 * Grow an aobj to a given number of pages. Right now we only adjust the swap 556 * slots. We could additionally handle page allocation directly, so that they 557 * don't happen through uvm_fault(). That would allow us to use another 558 * mechanism for the swap slots other than malloc(). It is thus mandatory that 559 * the caller of these functions does not allow faults to happen in case of 560 * growth error. 561 */ 562 int 563 uao_grow_array(struct uvm_object *uobj, int pages) 564 { 565 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 566 int i, *new_swslots; 567 568 KASSERT(aobj->u_pages <= UAO_SWHASH_THRESHOLD); 569 570 new_swslots = malloc(pages * sizeof(int), M_UVMAOBJ, 571 M_WAITOK | M_CANFAIL | M_ZERO); 572 if (new_swslots == NULL) 573 return ENOMEM; 574 575 for (i = 0; i < aobj->u_pages; i++) 576 new_swslots[i] = aobj->u_swslots[i]; 577 578 free(aobj->u_swslots, M_UVMAOBJ, 0); 579 580 aobj->u_swslots = new_swslots; 581 aobj->u_pages = pages; 582 583 return 0; 584 } 585 586 int 587 uao_grow_hash(struct uvm_object *uobj, int pages) 588 { 589 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 590 struct uao_swhash *new_swhash; 591 struct uao_swhash_elt *elt; 592 unsigned long new_hashmask; 593 int i; 594 595 KASSERT(pages > UAO_SWHASH_THRESHOLD); 596 597 /* 598 * If the size of the hash table doesn't change, all we need to do is 599 * to adjust the page count. 600 */ 601 if (UAO_SWHASH_BUCKETS(aobj->u_pages) == UAO_SWHASH_BUCKETS(pages)) { 602 aobj->u_pages = pages; 603 return 0; 604 } 605 606 KASSERT(UAO_SWHASH_BUCKETS(aobj->u_pages) < UAO_SWHASH_BUCKETS(pages)); 607 608 new_swhash = hashinit(UAO_SWHASH_BUCKETS(pages), M_UVMAOBJ, 609 M_WAITOK | M_CANFAIL, &new_hashmask); 610 if (new_swhash == NULL) 611 return ENOMEM; 612 613 for (i = 0; i < UAO_SWHASH_BUCKETS(aobj->u_pages); i++) { 614 while (LIST_EMPTY(&aobj->u_swhash[i]) == 0) { 615 elt = LIST_FIRST(&aobj->u_swhash[i]); 616 LIST_REMOVE(elt, list); 617 LIST_INSERT_HEAD(&new_swhash[i], elt, list); 618 } 619 } 620 621 free(aobj->u_swhash, M_UVMAOBJ, 0); 622 623 aobj->u_swhash = new_swhash; 624 aobj->u_pages = pages; 625 aobj->u_swhashmask = new_hashmask; 626 627 return 0; 628 } 629 630 int 631 uao_grow_convert(struct uvm_object *uobj, int pages) 632 { 633 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 634 struct uao_swhash *new_swhash; 635 struct uao_swhash_elt *elt; 636 unsigned long new_hashmask; 637 int i, *old_swslots; 638 639 new_swhash = hashinit(UAO_SWHASH_BUCKETS(pages), M_UVMAOBJ, 640 M_WAITOK | M_CANFAIL, &new_hashmask); 641 if (new_swhash == NULL) 642 return ENOMEM; 643 644 /* Set these now, so we can use uao_find_swhash_elt(). */ 645 old_swslots = aobj->u_swslots; 646 aobj->u_swhash = new_swhash; 647 aobj->u_swhashmask = new_hashmask; 648 649 for (i = 0; i < aobj->u_pages; i++) { 650 if (old_swslots[i] != 0) { 651 elt = uao_find_swhash_elt(aobj, i, TRUE); 652 elt->count++; 653 UAO_SWHASH_ELT_PAGESLOT(elt, i) = old_swslots[i]; 654 } 655 } 656 657 free(old_swslots, M_UVMAOBJ, 0); 658 aobj->u_pages = pages; 659 660 return 0; 661 } 662 663 int 664 uao_grow(struct uvm_object *uobj, int pages) 665 { 666 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 667 668 KASSERT(pages > aobj->u_pages); 669 670 /* 671 * Distinguish between three possible cases: 672 * 1. aobj uses hash and hash size needs to be adjusted. 673 * 2. aobj uses array and array size needs to be adjusted. 674 * 3. aobj uses array and must be converted to hash. 675 */ 676 if (pages <= UAO_SWHASH_THRESHOLD) 677 return uao_grow_array(uobj, pages); /* case 2 */ 678 else if (aobj->u_pages > UAO_SWHASH_THRESHOLD) 679 return uao_grow_hash(uobj, pages); /* case 1 */ 680 else 681 return uao_grow_convert(uobj, pages); 682 } 683 684 /* 685 * uao_create: create an aobj of the given size and return its uvm_object. 686 * 687 * => for normal use, flags are zero or UAO_FLAG_CANFAIL. 688 * => for the kernel object, the flags are: 689 * UAO_FLAG_KERNOBJ - allocate the kernel object (can only happen once) 690 * UAO_FLAG_KERNSWAP - enable swapping of kernel object (" ") 691 */ 692 struct uvm_object * 693 uao_create(vsize_t size, int flags) 694 { 695 static struct uvm_aobj kernel_object_store; /* home of kernel_object */ 696 static int kobj_alloced = 0; /* not allocated yet */ 697 int pages = round_page(size) >> PAGE_SHIFT; 698 int refs = UVM_OBJ_KERN; 699 int mflags; 700 struct uvm_aobj *aobj; 701 702 /* malloc a new aobj unless we are asked for the kernel object */ 703 if (flags & UAO_FLAG_KERNOBJ) { /* want kernel object? */ 704 if (kobj_alloced) 705 panic("uao_create: kernel object already allocated"); 706 707 aobj = &kernel_object_store; 708 aobj->u_pages = pages; 709 aobj->u_flags = UAO_FLAG_NOSWAP; /* no swap to start */ 710 /* we are special, we never die */ 711 kobj_alloced = UAO_FLAG_KERNOBJ; 712 } else if (flags & UAO_FLAG_KERNSWAP) { 713 aobj = &kernel_object_store; 714 if (kobj_alloced != UAO_FLAG_KERNOBJ) 715 panic("uao_create: asked to enable swap on kernel object"); 716 kobj_alloced = UAO_FLAG_KERNSWAP; 717 } else { /* normal object */ 718 aobj = pool_get(&uvm_aobj_pool, PR_WAITOK); 719 aobj->u_pages = pages; 720 aobj->u_flags = 0; /* normal object */ 721 refs = 1; /* normal object so 1 ref */ 722 } 723 724 /* allocate hash/array if necessary */ 725 if (flags == 0 || (flags & (UAO_FLAG_KERNSWAP | UAO_FLAG_CANFAIL))) { 726 if (flags) 727 mflags = M_NOWAIT; 728 else 729 mflags = M_WAITOK; 730 731 /* allocate hash table or array depending on object size */ 732 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 733 aobj->u_swhash = hashinit(UAO_SWHASH_BUCKETS(pages), 734 M_UVMAOBJ, mflags, &aobj->u_swhashmask); 735 if (aobj->u_swhash == NULL) { 736 if (flags & UAO_FLAG_CANFAIL) { 737 pool_put(&uvm_aobj_pool, aobj); 738 return (NULL); 739 } 740 panic("uao_create: hashinit swhash failed"); 741 } 742 } else { 743 aobj->u_swslots = malloc(pages * sizeof(int), 744 M_UVMAOBJ, mflags|M_ZERO); 745 if (aobj->u_swslots == NULL) { 746 if (flags & UAO_FLAG_CANFAIL) { 747 pool_put(&uvm_aobj_pool, aobj); 748 return (NULL); 749 } 750 panic("uao_create: malloc swslots failed"); 751 } 752 } 753 754 if (flags & UAO_FLAG_KERNSWAP) { 755 aobj->u_flags &= ~UAO_FLAG_NOSWAP; /* clear noswap */ 756 return(&aobj->u_obj); 757 /* done! */ 758 } 759 } 760 761 uvm_objinit(&aobj->u_obj, &aobj_pager, refs); 762 763 /* now that aobj is ready, add it to the global list */ 764 mtx_enter(&uao_list_lock); 765 LIST_INSERT_HEAD(&uao_list, aobj, u_list); 766 mtx_leave(&uao_list_lock); 767 768 return(&aobj->u_obj); 769 } 770 771 772 773 /* 774 * uao_init: set up aobj pager subsystem 775 * 776 * => called at boot time from uvm_pager_init() 777 */ 778 void 779 uao_init(void) 780 { 781 static int uao_initialized; 782 783 if (uao_initialized) 784 return; 785 uao_initialized = TRUE; 786 787 /* 788 * NOTE: Pages for this pool must not come from a pageable 789 * kernel map! 790 */ 791 pool_init(&uao_swhash_elt_pool, sizeof(struct uao_swhash_elt), 792 0, 0, 0, "uaoeltpl", &pool_allocator_nointr); 793 794 pool_init(&uvm_aobj_pool, sizeof(struct uvm_aobj), 0, 0, 0, 795 "aobjpl", &pool_allocator_nointr); 796 } 797 798 /* 799 * uao_reference: add a ref to an aobj 800 */ 801 void 802 uao_reference(struct uvm_object *uobj) 803 { 804 uao_reference_locked(uobj); 805 } 806 807 /* 808 * uao_reference_locked: add a ref to an aobj 809 */ 810 void 811 uao_reference_locked(struct uvm_object *uobj) 812 { 813 814 /* kernel_object already has plenty of references, leave it alone. */ 815 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) 816 return; 817 818 uobj->uo_refs++; /* bump! */ 819 } 820 821 822 /* 823 * uao_detach: drop a reference to an aobj 824 */ 825 void 826 uao_detach(struct uvm_object *uobj) 827 { 828 uao_detach_locked(uobj); 829 } 830 831 832 /* 833 * uao_detach_locked: drop a reference to an aobj 834 * 835 * => aobj may freed upon return. 836 */ 837 void 838 uao_detach_locked(struct uvm_object *uobj) 839 { 840 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 841 struct vm_page *pg; 842 843 /* detaching from kernel_object is a noop. */ 844 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) { 845 return; 846 } 847 848 uobj->uo_refs--; /* drop ref! */ 849 if (uobj->uo_refs) { /* still more refs? */ 850 return; 851 } 852 853 /* remove the aobj from the global list. */ 854 mtx_enter(&uao_list_lock); 855 LIST_REMOVE(aobj, u_list); 856 mtx_leave(&uao_list_lock); 857 858 /* 859 * Free all pages left in the object. If they're busy, wait 860 * for them to become available before we kill it. 861 * Release swap resources then free the page. 862 */ 863 uvm_lock_pageq(); 864 while((pg = RB_ROOT(&uobj->memt)) != NULL) { 865 if (pg->pg_flags & PG_BUSY) { 866 atomic_setbits_int(&pg->pg_flags, PG_WANTED); 867 uvm_unlock_pageq(); 868 UVM_WAIT(pg, 0, "uao_det", 0); 869 uvm_lock_pageq(); 870 continue; 871 } 872 pmap_page_protect(pg, VM_PROT_NONE); 873 uao_dropswap(&aobj->u_obj, pg->offset >> PAGE_SHIFT); 874 uvm_pagefree(pg); 875 } 876 uvm_unlock_pageq(); 877 878 /* finally, free the rest. */ 879 uao_free(aobj); 880 } 881 882 /* 883 * uao_flush: "flush" pages out of a uvm object 884 * 885 * => if PGO_CLEANIT is not set, then we will not block. 886 * => if PGO_ALLPAGE is set, then all pages in the object are valid targets 887 * for flushing. 888 * => NOTE: we are allowed to lock the page queues, so the caller 889 * must not be holding the lock on them [e.g. pagedaemon had 890 * better not call us with the queues locked] 891 * => we return TRUE unless we encountered some sort of I/O error 892 * XXXJRT currently never happens, as we never directly initiate 893 * XXXJRT I/O 894 */ 895 896 #define UAO_HASH_PENALTY 4 /* XXX: a guess */ 897 898 boolean_t 899 uao_flush(struct uvm_object *uobj, voff_t start, voff_t stop, int flags) 900 { 901 struct uvm_aobj *aobj = (struct uvm_aobj *) uobj; 902 struct vm_page *pp; 903 voff_t curoff; 904 905 if (flags & PGO_ALLPAGES) { 906 start = 0; 907 stop = (voff_t)aobj->u_pages << PAGE_SHIFT; 908 } else { 909 start = trunc_page(start); 910 stop = round_page(stop); 911 if (stop > ((voff_t)aobj->u_pages << PAGE_SHIFT)) { 912 printf("uao_flush: strange, got an out of range " 913 "flush (fixed)\n"); 914 stop = (voff_t)aobj->u_pages << PAGE_SHIFT; 915 } 916 } 917 918 /* 919 * Don't need to do any work here if we're not freeing 920 * or deactivating pages. 921 */ 922 if ((flags & (PGO_DEACTIVATE|PGO_FREE)) == 0) 923 return (TRUE); 924 925 curoff = start; 926 for (;;) { 927 if (curoff < stop) { 928 pp = uvm_pagelookup(uobj, curoff); 929 curoff += PAGE_SIZE; 930 if (pp == NULL) 931 continue; 932 } else { 933 break; 934 } 935 936 /* Make sure page is unbusy, else wait for it. */ 937 if (pp->pg_flags & PG_BUSY) { 938 atomic_setbits_int(&pp->pg_flags, PG_WANTED); 939 UVM_WAIT(pp, 0, "uaoflsh", 0); 940 curoff -= PAGE_SIZE; 941 continue; 942 } 943 944 switch (flags & (PGO_CLEANIT|PGO_FREE|PGO_DEACTIVATE)) { 945 /* 946 * XXX In these first 3 cases, we always just 947 * XXX deactivate the page. We may want to 948 * XXX handle the different cases more specifically 949 * XXX in the future. 950 */ 951 case PGO_CLEANIT|PGO_FREE: 952 /* FALLTHROUGH */ 953 case PGO_CLEANIT|PGO_DEACTIVATE: 954 /* FALLTHROUGH */ 955 case PGO_DEACTIVATE: 956 deactivate_it: 957 /* skip the page if it's loaned or wired */ 958 if (pp->loan_count != 0 || 959 pp->wire_count != 0) 960 continue; 961 962 uvm_lock_pageq(); 963 /* zap all mappings for the page. */ 964 pmap_page_protect(pp, VM_PROT_NONE); 965 966 /* ...and deactivate the page. */ 967 uvm_pagedeactivate(pp); 968 uvm_unlock_pageq(); 969 970 continue; 971 case PGO_FREE: 972 /* 973 * If there are multiple references to 974 * the object, just deactivate the page. 975 */ 976 if (uobj->uo_refs > 1) 977 goto deactivate_it; 978 979 /* XXX skip the page if it's loaned or wired */ 980 if (pp->loan_count != 0 || 981 pp->wire_count != 0) 982 continue; 983 984 /* zap all mappings for the page. */ 985 pmap_page_protect(pp, VM_PROT_NONE); 986 987 uao_dropswap(uobj, pp->offset >> PAGE_SHIFT); 988 uvm_lock_pageq(); 989 uvm_pagefree(pp); 990 uvm_unlock_pageq(); 991 992 continue; 993 default: 994 panic("uao_flush: weird flags"); 995 } 996 } 997 998 return (TRUE); 999 } 1000 1001 /* 1002 * uao_get: fetch me a page 1003 * 1004 * we have three cases: 1005 * 1: page is resident -> just return the page. 1006 * 2: page is zero-fill -> allocate a new page and zero it. 1007 * 3: page is swapped out -> fetch the page from swap. 1008 * 1009 * cases 1 and 2 can be handled with PGO_LOCKED, case 3 cannot. 1010 * so, if the "center" page hits case 3 (or any page, with PGO_ALLPAGES), 1011 * then we will need to return VM_PAGER_UNLOCK. 1012 * 1013 * => flags: PGO_ALLPAGES: get all of the pages 1014 * PGO_LOCKED: fault data structures are locked 1015 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 1016 * => NOTE: caller must check for released pages!! 1017 */ 1018 static int 1019 uao_get(struct uvm_object *uobj, voff_t offset, struct vm_page **pps, 1020 int *npagesp, int centeridx, vm_prot_t access_type, int advice, int flags) 1021 { 1022 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 1023 voff_t current_offset; 1024 vm_page_t ptmp; 1025 int lcv, gotpages, maxpages, swslot, rv, pageidx; 1026 boolean_t done; 1027 1028 /* get number of pages */ 1029 maxpages = *npagesp; 1030 1031 /* step 1: handled the case where fault data structures are locked. */ 1032 if (flags & PGO_LOCKED) { 1033 /* step 1a: get pages that are already resident. */ 1034 1035 done = TRUE; /* be optimistic */ 1036 gotpages = 0; /* # of pages we got so far */ 1037 1038 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 1039 lcv++, current_offset += PAGE_SIZE) { 1040 /* do we care about this page? if not, skip it */ 1041 if (pps[lcv] == PGO_DONTCARE) 1042 continue; 1043 1044 ptmp = uvm_pagelookup(uobj, current_offset); 1045 1046 /* 1047 * if page is new, attempt to allocate the page, 1048 * zero-fill'd. 1049 */ 1050 if (ptmp == NULL && uao_find_swslot(aobj, 1051 current_offset >> PAGE_SHIFT) == 0) { 1052 ptmp = uvm_pagealloc(uobj, current_offset, 1053 NULL, UVM_PGA_ZERO); 1054 if (ptmp) { 1055 /* new page */ 1056 atomic_clearbits_int(&ptmp->pg_flags, 1057 PG_BUSY|PG_FAKE); 1058 atomic_setbits_int(&ptmp->pg_flags, 1059 PQ_AOBJ); 1060 UVM_PAGE_OWN(ptmp, NULL); 1061 } 1062 } 1063 1064 /* to be useful must get a non-busy page */ 1065 if (ptmp == NULL || 1066 (ptmp->pg_flags & PG_BUSY) != 0) { 1067 if (lcv == centeridx || 1068 (flags & PGO_ALLPAGES) != 0) 1069 /* need to do a wait or I/O! */ 1070 done = FALSE; 1071 continue; 1072 } 1073 1074 /* 1075 * useful page: busy it and plug it in our 1076 * result array 1077 */ 1078 /* caller must un-busy this page */ 1079 atomic_setbits_int(&ptmp->pg_flags, PG_BUSY); 1080 UVM_PAGE_OWN(ptmp, "uao_get1"); 1081 pps[lcv] = ptmp; 1082 gotpages++; 1083 1084 } 1085 1086 /* 1087 * step 1b: now we've either done everything needed or we 1088 * to unlock and do some waiting or I/O. 1089 */ 1090 *npagesp = gotpages; 1091 if (done) 1092 /* bingo! */ 1093 return(VM_PAGER_OK); 1094 else 1095 /* EEK! Need to unlock and I/O */ 1096 return(VM_PAGER_UNLOCK); 1097 } 1098 1099 /* 1100 * step 2: get non-resident or busy pages. 1101 * data structures are unlocked. 1102 */ 1103 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 1104 lcv++, current_offset += PAGE_SIZE) { 1105 /* 1106 * - skip over pages we've already gotten or don't want 1107 * - skip over pages we don't _have_ to get 1108 */ 1109 if (pps[lcv] != NULL || 1110 (lcv != centeridx && (flags & PGO_ALLPAGES) == 0)) 1111 continue; 1112 1113 pageidx = current_offset >> PAGE_SHIFT; 1114 1115 /* 1116 * we have yet to locate the current page (pps[lcv]). we 1117 * first look for a page that is already at the current offset. 1118 * if we find a page, we check to see if it is busy or 1119 * released. if that is the case, then we sleep on the page 1120 * until it is no longer busy or released and repeat the lookup. 1121 * if the page we found is neither busy nor released, then we 1122 * busy it (so we own it) and plug it into pps[lcv]. this 1123 * 'break's the following while loop and indicates we are 1124 * ready to move on to the next page in the "lcv" loop above. 1125 * 1126 * if we exit the while loop with pps[lcv] still set to NULL, 1127 * then it means that we allocated a new busy/fake/clean page 1128 * ptmp in the object and we need to do I/O to fill in the data. 1129 */ 1130 1131 /* top of "pps" while loop */ 1132 while (pps[lcv] == NULL) { 1133 /* look for a resident page */ 1134 ptmp = uvm_pagelookup(uobj, current_offset); 1135 1136 /* not resident? allocate one now (if we can) */ 1137 if (ptmp == NULL) { 1138 1139 ptmp = uvm_pagealloc(uobj, current_offset, 1140 NULL, 0); 1141 1142 /* out of RAM? */ 1143 if (ptmp == NULL) { 1144 uvm_wait("uao_getpage"); 1145 /* goto top of pps while loop */ 1146 continue; 1147 } 1148 1149 /* 1150 * safe with PQ's unlocked: because we just 1151 * alloc'd the page 1152 */ 1153 atomic_setbits_int(&ptmp->pg_flags, PQ_AOBJ); 1154 1155 /* 1156 * got new page ready for I/O. break pps while 1157 * loop. pps[lcv] is still NULL. 1158 */ 1159 break; 1160 } 1161 1162 /* page is there, see if we need to wait on it */ 1163 if ((ptmp->pg_flags & PG_BUSY) != 0) { 1164 atomic_setbits_int(&ptmp->pg_flags, PG_WANTED); 1165 UVM_WAIT(ptmp, FALSE, "uao_get", 0); 1166 continue; /* goto top of pps while loop */ 1167 } 1168 1169 /* 1170 * if we get here then the page has become resident and 1171 * unbusy between steps 1 and 2. we busy it now (so we 1172 * own it) and set pps[lcv] (so that we exit the while 1173 * loop). 1174 */ 1175 /* we own it, caller must un-busy */ 1176 atomic_setbits_int(&ptmp->pg_flags, PG_BUSY); 1177 UVM_PAGE_OWN(ptmp, "uao_get2"); 1178 pps[lcv] = ptmp; 1179 } 1180 1181 /* 1182 * if we own the valid page at the correct offset, pps[lcv] will 1183 * point to it. nothing more to do except go to the next page. 1184 */ 1185 if (pps[lcv]) 1186 continue; /* next lcv */ 1187 1188 /* 1189 * we have a "fake/busy/clean" page that we just allocated. 1190 * do the needed "i/o", either reading from swap or zeroing. 1191 */ 1192 swslot = uao_find_swslot(aobj, pageidx); 1193 1194 /* just zero the page if there's nothing in swap. */ 1195 if (swslot == 0) { 1196 /* page hasn't existed before, just zero it. */ 1197 uvm_pagezero(ptmp); 1198 } else { 1199 /* page in the swapped-out page. */ 1200 rv = uvm_swap_get(ptmp, swslot, PGO_SYNCIO); 1201 1202 /* I/O done. check for errors. */ 1203 if (rv != VM_PAGER_OK) { 1204 /* 1205 * remove the swap slot from the aobj 1206 * and mark the aobj as having no real slot. 1207 * don't free the swap slot, thus preventing 1208 * it from being used again. 1209 */ 1210 swslot = uao_set_swslot(&aobj->u_obj, pageidx, 1211 SWSLOT_BAD); 1212 uvm_swap_markbad(swslot, 1); 1213 1214 if (ptmp->pg_flags & PG_WANTED) 1215 wakeup(ptmp); 1216 atomic_clearbits_int(&ptmp->pg_flags, 1217 PG_WANTED|PG_BUSY); 1218 UVM_PAGE_OWN(ptmp, NULL); 1219 uvm_lock_pageq(); 1220 uvm_pagefree(ptmp); 1221 uvm_unlock_pageq(); 1222 1223 return (rv); 1224 } 1225 } 1226 1227 /* 1228 * we got the page! clear the fake flag (indicates valid 1229 * data now in page) and plug into our result array. note 1230 * that page is still busy. 1231 * 1232 * it is the callers job to: 1233 * => check if the page is released 1234 * => unbusy the page 1235 * => activate the page 1236 */ 1237 1238 /* data is valid ... */ 1239 atomic_clearbits_int(&ptmp->pg_flags, PG_FAKE); 1240 pmap_clear_modify(ptmp); /* ... and clean */ 1241 pps[lcv] = ptmp; 1242 1243 } /* lcv loop */ 1244 1245 return(VM_PAGER_OK); 1246 } 1247 1248 /* 1249 * uao_dropswap: release any swap resources from this aobj page. 1250 */ 1251 int 1252 uao_dropswap(struct uvm_object *uobj, int pageidx) 1253 { 1254 int slot; 1255 1256 slot = uao_set_swslot(uobj, pageidx, 0); 1257 if (slot) { 1258 uvm_swap_free(slot, 1); 1259 } 1260 return (slot); 1261 } 1262 1263 /* 1264 * page in every page in every aobj that is paged-out to a range of swslots. 1265 * 1266 * => returns TRUE if pagein was aborted due to lack of memory. 1267 */ 1268 boolean_t 1269 uao_swap_off(int startslot, int endslot) 1270 { 1271 struct uvm_aobj *aobj, *nextaobj, *prevaobj = NULL; 1272 1273 /* walk the list of all aobjs. */ 1274 mtx_enter(&uao_list_lock); 1275 1276 for (aobj = LIST_FIRST(&uao_list); 1277 aobj != NULL; 1278 aobj = nextaobj) { 1279 boolean_t rv; 1280 1281 /* 1282 * add a ref to the aobj so it doesn't disappear 1283 * while we're working. 1284 */ 1285 uao_reference_locked(&aobj->u_obj); 1286 1287 /* 1288 * now it's safe to unlock the uao list. 1289 * note that lock interleaving is alright with IPL_NONE mutexes. 1290 */ 1291 mtx_leave(&uao_list_lock); 1292 1293 if (prevaobj) { 1294 uao_detach_locked(&prevaobj->u_obj); 1295 prevaobj = NULL; 1296 } 1297 1298 /* 1299 * page in any pages in the swslot range. 1300 * if there's an error, abort and return the error. 1301 */ 1302 rv = uao_pagein(aobj, startslot, endslot); 1303 if (rv) { 1304 uao_detach_locked(&aobj->u_obj); 1305 return rv; 1306 } 1307 1308 /* 1309 * we're done with this aobj. 1310 * relock the list and drop our ref on the aobj. 1311 */ 1312 mtx_enter(&uao_list_lock); 1313 nextaobj = LIST_NEXT(aobj, u_list); 1314 /* 1315 * prevaobj means that we have an object that we need 1316 * to drop a reference for. We can't just drop it now with 1317 * the list locked since that could cause lock recursion in 1318 * the case where we reduce the refcount to 0. It will be 1319 * released the next time we drop the list lock. 1320 */ 1321 prevaobj = aobj; 1322 } 1323 1324 /* done with traversal, unlock the list */ 1325 mtx_leave(&uao_list_lock); 1326 if (prevaobj) { 1327 uao_detach_locked(&prevaobj->u_obj); 1328 } 1329 return FALSE; 1330 } 1331 1332 /* 1333 * page in any pages from aobj in the given range. 1334 * 1335 * => returns TRUE if pagein was aborted due to lack of memory. 1336 */ 1337 static boolean_t 1338 uao_pagein(struct uvm_aobj *aobj, int startslot, int endslot) 1339 { 1340 boolean_t rv; 1341 1342 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 1343 struct uao_swhash_elt *elt; 1344 int bucket; 1345 1346 restart: 1347 for (bucket = aobj->u_swhashmask; bucket >= 0; bucket--) { 1348 for (elt = LIST_FIRST(&aobj->u_swhash[bucket]); 1349 elt != NULL; 1350 elt = LIST_NEXT(elt, list)) { 1351 int i; 1352 1353 for (i = 0; i < UAO_SWHASH_CLUSTER_SIZE; i++) { 1354 int slot = elt->slots[i]; 1355 1356 /* if slot isn't in range, skip it. */ 1357 if (slot < startslot || 1358 slot >= endslot) { 1359 continue; 1360 } 1361 1362 /* 1363 * process the page, 1364 * the start over on this object 1365 * since the swhash elt 1366 * may have been freed. 1367 */ 1368 rv = uao_pagein_page(aobj, 1369 UAO_SWHASH_ELT_PAGEIDX_BASE(elt) + i); 1370 if (rv) { 1371 return rv; 1372 } 1373 goto restart; 1374 } 1375 } 1376 } 1377 } else { 1378 int i; 1379 1380 for (i = 0; i < aobj->u_pages; i++) { 1381 int slot = aobj->u_swslots[i]; 1382 1383 /* if the slot isn't in range, skip it */ 1384 if (slot < startslot || slot >= endslot) { 1385 continue; 1386 } 1387 1388 /* process the page. */ 1389 rv = uao_pagein_page(aobj, i); 1390 if (rv) { 1391 return rv; 1392 } 1393 } 1394 } 1395 1396 return FALSE; 1397 } 1398 1399 /* 1400 * page in a page from an aobj. used for swap_off. 1401 * returns TRUE if pagein was aborted due to lack of memory. 1402 */ 1403 static boolean_t 1404 uao_pagein_page(struct uvm_aobj *aobj, int pageidx) 1405 { 1406 struct vm_page *pg; 1407 int rv, slot, npages; 1408 1409 pg = NULL; 1410 npages = 1; 1411 rv = uao_get(&aobj->u_obj, (voff_t)pageidx << PAGE_SHIFT, 1412 &pg, &npages, 0, VM_PROT_READ|VM_PROT_WRITE, 0, 0); 1413 1414 switch (rv) { 1415 case VM_PAGER_OK: 1416 break; 1417 1418 case VM_PAGER_ERROR: 1419 case VM_PAGER_REFAULT: 1420 /* 1421 * nothing more to do on errors. 1422 * VM_PAGER_REFAULT can only mean that the anon was freed, 1423 * so again there's nothing to do. 1424 */ 1425 return FALSE; 1426 } 1427 1428 /* 1429 * ok, we've got the page now. 1430 * mark it as dirty, clear its swslot and un-busy it. 1431 */ 1432 slot = uao_set_swslot(&aobj->u_obj, pageidx, 0); 1433 uvm_swap_free(slot, 1); 1434 atomic_clearbits_int(&pg->pg_flags, PG_BUSY|PG_CLEAN|PG_FAKE); 1435 UVM_PAGE_OWN(pg, NULL); 1436 1437 /* deactivate the page (to put it on a page queue). */ 1438 pmap_clear_reference(pg); 1439 uvm_lock_pageq(); 1440 uvm_pagedeactivate(pg); 1441 uvm_unlock_pageq(); 1442 1443 return FALSE; 1444 } 1445 1446 /* 1447 * XXX pedro: Once we are comfortable enough with this function, we can adapt 1448 * uao_free() to use it. 1449 * 1450 * uao_dropswap_range: drop swapslots in the range. 1451 * 1452 * => aobj must be locked and is returned locked. 1453 * => start is inclusive. end is exclusive. 1454 */ 1455 void 1456 uao_dropswap_range(struct uvm_object *uobj, voff_t start, voff_t end) 1457 { 1458 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 1459 int swpgonlydelta = 0; 1460 1461 /* KASSERT(mutex_owned(uobj->vmobjlock)); */ 1462 1463 if (end == 0) { 1464 end = INT64_MAX; 1465 } 1466 1467 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 1468 int i, hashbuckets = aobj->u_swhashmask + 1; 1469 voff_t taghi; 1470 voff_t taglo; 1471 1472 taglo = UAO_SWHASH_ELT_TAG(start); 1473 taghi = UAO_SWHASH_ELT_TAG(end); 1474 1475 for (i = 0; i < hashbuckets; i++) { 1476 struct uao_swhash_elt *elt, *next; 1477 1478 for (elt = LIST_FIRST(&aobj->u_swhash[i]); 1479 elt != NULL; 1480 elt = next) { 1481 int startidx, endidx; 1482 int j; 1483 1484 next = LIST_NEXT(elt, list); 1485 1486 if (elt->tag < taglo || taghi < elt->tag) { 1487 continue; 1488 } 1489 1490 if (elt->tag == taglo) { 1491 startidx = 1492 UAO_SWHASH_ELT_PAGESLOT_IDX(start); 1493 } else { 1494 startidx = 0; 1495 } 1496 1497 if (elt->tag == taghi) { 1498 endidx = 1499 UAO_SWHASH_ELT_PAGESLOT_IDX(end); 1500 } else { 1501 endidx = UAO_SWHASH_CLUSTER_SIZE; 1502 } 1503 1504 for (j = startidx; j < endidx; j++) { 1505 int slot = elt->slots[j]; 1506 1507 KASSERT(uvm_pagelookup(&aobj->u_obj, 1508 (voff_t)(UAO_SWHASH_ELT_PAGEIDX_BASE(elt) 1509 + j) << PAGE_SHIFT) == NULL); 1510 1511 if (slot > 0) { 1512 uvm_swap_free(slot, 1); 1513 swpgonlydelta++; 1514 KASSERT(elt->count > 0); 1515 elt->slots[j] = 0; 1516 elt->count--; 1517 } 1518 } 1519 1520 if (elt->count == 0) { 1521 LIST_REMOVE(elt, list); 1522 pool_put(&uao_swhash_elt_pool, elt); 1523 } 1524 } 1525 } 1526 } else { 1527 int i; 1528 1529 if (aobj->u_pages < end) { 1530 end = aobj->u_pages; 1531 } 1532 for (i = start; i < end; i++) { 1533 int slot = aobj->u_swslots[i]; 1534 1535 if (slot > 0) { 1536 uvm_swap_free(slot, 1); 1537 swpgonlydelta++; 1538 } 1539 } 1540 } 1541 1542 /* 1543 * adjust the counter of pages only in swap for all 1544 * the swap slots we've freed. 1545 */ 1546 if (swpgonlydelta > 0) { 1547 simple_lock(&uvm.swap_data_lock); 1548 KASSERT(uvmexp.swpgonly >= swpgonlydelta); 1549 uvmexp.swpgonly -= swpgonlydelta; 1550 simple_unlock(&uvm.swap_data_lock); 1551 } 1552 } 1553