1 /* $OpenBSD: uvm_aobj.c,v 1.89 2020/10/21 09:08:14 mpi 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/malloc.h> 43 #include <sys/kernel.h> 44 #include <sys/pool.h> 45 #include <sys/stdint.h> 46 #include <sys/atomic.h> 47 48 #include <uvm/uvm.h> 49 50 /* 51 * an aobj manages anonymous-memory backed uvm_objects. in addition 52 * to keeping the list of resident pages, it also keeps a list of 53 * allocated swap blocks. depending on the size of the aobj this list 54 * of allocated swap blocks is either stored in an array (small objects) 55 * or in a hash table (large objects). 56 */ 57 58 /* 59 * local structures 60 */ 61 62 /* 63 * for hash tables, we break the address space of the aobj into blocks 64 * of UAO_SWHASH_CLUSTER_SIZE pages. we require the cluster size to 65 * be a power of two. 66 */ 67 #define UAO_SWHASH_CLUSTER_SHIFT 4 68 #define UAO_SWHASH_CLUSTER_SIZE (1 << UAO_SWHASH_CLUSTER_SHIFT) 69 70 /* get the "tag" for this page index */ 71 #define UAO_SWHASH_ELT_TAG(PAGEIDX) \ 72 ((PAGEIDX) >> UAO_SWHASH_CLUSTER_SHIFT) 73 74 /* given an ELT and a page index, find the swap slot */ 75 #define UAO_SWHASH_ELT_PAGESLOT_IDX(PAGEIDX) \ 76 ((PAGEIDX) & (UAO_SWHASH_CLUSTER_SIZE - 1)) 77 #define UAO_SWHASH_ELT_PAGESLOT(ELT, PAGEIDX) \ 78 ((ELT)->slots[(PAGEIDX) & (UAO_SWHASH_CLUSTER_SIZE - 1)]) 79 80 /* given an ELT, return its pageidx base */ 81 #define UAO_SWHASH_ELT_PAGEIDX_BASE(ELT) \ 82 ((ELT)->tag << UAO_SWHASH_CLUSTER_SHIFT) 83 84 /* 85 * the swhash hash function 86 */ 87 #define UAO_SWHASH_HASH(AOBJ, PAGEIDX) \ 88 (&(AOBJ)->u_swhash[(((PAGEIDX) >> UAO_SWHASH_CLUSTER_SHIFT) \ 89 & (AOBJ)->u_swhashmask)]) 90 91 /* 92 * the swhash threshold determines if we will use an array or a 93 * hash table to store the list of allocated swap blocks. 94 */ 95 96 #define UAO_SWHASH_THRESHOLD (UAO_SWHASH_CLUSTER_SIZE * 4) 97 98 /* 99 * the number of buckets in a swhash, with an upper bound 100 */ 101 #define UAO_SWHASH_MAXBUCKETS 256 102 #define UAO_SWHASH_BUCKETS(pages) \ 103 (min((pages) >> UAO_SWHASH_CLUSTER_SHIFT, UAO_SWHASH_MAXBUCKETS)) 104 105 106 /* 107 * uao_swhash_elt: when a hash table is being used, this structure defines 108 * the format of an entry in the bucket list. 109 */ 110 struct uao_swhash_elt { 111 LIST_ENTRY(uao_swhash_elt) list; /* the hash list */ 112 voff_t tag; /* our 'tag' */ 113 int count; /* our number of active slots */ 114 int slots[UAO_SWHASH_CLUSTER_SIZE]; /* the slots */ 115 }; 116 117 /* 118 * uao_swhash: the swap hash table structure 119 */ 120 LIST_HEAD(uao_swhash, uao_swhash_elt); 121 122 /* 123 * uao_swhash_elt_pool: pool of uao_swhash_elt structures 124 */ 125 struct pool uao_swhash_elt_pool; 126 127 /* 128 * uvm_aobj: the actual anon-backed uvm_object 129 * 130 * => the uvm_object is at the top of the structure, this allows 131 * (struct uvm_aobj *) == (struct uvm_object *) 132 * => only one of u_swslots and u_swhash is used in any given aobj 133 */ 134 struct uvm_aobj { 135 struct uvm_object u_obj; /* has: pgops, memt, #pages, #refs */ 136 int u_pages; /* number of pages in entire object */ 137 int u_flags; /* the flags (see uvm_aobj.h) */ 138 /* 139 * Either an array or hashtable (array of bucket heads) of 140 * offset -> swapslot mappings for the aobj. 141 */ 142 #define u_swslots u_swap.slot_array 143 #define u_swhash u_swap.slot_hash 144 union swslots { 145 int *slot_array; 146 struct uao_swhash *slot_hash; 147 } u_swap; 148 u_long u_swhashmask; /* mask for hashtable */ 149 LIST_ENTRY(uvm_aobj) u_list; /* global list of aobjs */ 150 }; 151 152 /* 153 * uvm_aobj_pool: pool of uvm_aobj structures 154 */ 155 struct pool uvm_aobj_pool; 156 157 /* 158 * local functions 159 */ 160 static struct uao_swhash_elt *uao_find_swhash_elt(struct uvm_aobj *, int, 161 boolean_t); 162 static int uao_find_swslot(struct uvm_aobj *, int); 163 static boolean_t uao_flush(struct uvm_object *, voff_t, 164 voff_t, int); 165 static void uao_free(struct uvm_aobj *); 166 static int uao_get(struct uvm_object *, voff_t, 167 vm_page_t *, int *, int, vm_prot_t, 168 int, int); 169 static boolean_t uao_pagein(struct uvm_aobj *, int, int); 170 static boolean_t uao_pagein_page(struct uvm_aobj *, int); 171 172 void uao_dropswap_range(struct uvm_object *, voff_t, voff_t); 173 void uao_shrink_flush(struct uvm_object *, int, int); 174 int uao_shrink_hash(struct uvm_object *, int); 175 int uao_shrink_array(struct uvm_object *, int); 176 int uao_shrink_convert(struct uvm_object *, int); 177 178 int uao_grow_hash(struct uvm_object *, int); 179 int uao_grow_array(struct uvm_object *, int); 180 int uao_grow_convert(struct uvm_object *, int); 181 182 /* 183 * aobj_pager 184 * 185 * note that some functions (e.g. put) are handled elsewhere 186 */ 187 const struct uvm_pagerops aobj_pager = { 188 .pgo_reference = uao_reference, 189 .pgo_detach = uao_detach, 190 .pgo_flush = uao_flush, 191 .pgo_get = uao_get, 192 }; 193 194 /* 195 * uao_list: global list of active aobjs, locked by uao_list_lock 196 * 197 * Lock ordering: generally the locking order is object lock, then list lock. 198 * in the case of swap off we have to iterate over the list, and thus the 199 * ordering is reversed. In that case we must use trylocking to prevent 200 * deadlock. 201 */ 202 static LIST_HEAD(aobjlist, uvm_aobj) uao_list = LIST_HEAD_INITIALIZER(uao_list); 203 static struct mutex uao_list_lock = MUTEX_INITIALIZER(IPL_NONE); 204 205 206 /* 207 * functions 208 */ 209 /* 210 * hash table/array related functions 211 */ 212 /* 213 * uao_find_swhash_elt: find (or create) a hash table entry for a page 214 * offset. 215 */ 216 static struct uao_swhash_elt * 217 uao_find_swhash_elt(struct uvm_aobj *aobj, int pageidx, boolean_t create) 218 { 219 struct uao_swhash *swhash; 220 struct uao_swhash_elt *elt; 221 voff_t page_tag; 222 223 swhash = UAO_SWHASH_HASH(aobj, pageidx); /* first hash to get bucket */ 224 page_tag = UAO_SWHASH_ELT_TAG(pageidx); /* tag to search for */ 225 226 /* now search the bucket for the requested tag */ 227 LIST_FOREACH(elt, swhash, list) { 228 if (elt->tag == page_tag) 229 return(elt); 230 } 231 232 /* fail now if we are not allowed to create a new entry in the bucket */ 233 if (!create) 234 return NULL; 235 236 /* allocate a new entry for the bucket and init/insert it in */ 237 elt = pool_get(&uao_swhash_elt_pool, PR_NOWAIT | PR_ZERO); 238 /* 239 * XXX We cannot sleep here as the hash table might disappear 240 * from under our feet. And we run the risk of deadlocking 241 * the pagedeamon. In fact this code will only be called by 242 * the pagedaemon and allocation will only fail if we 243 * exhausted the pagedeamon reserve. In that case we're 244 * doomed anyway, so panic. 245 */ 246 if (elt == NULL) 247 panic("%s: can't allocate entry", __func__); 248 LIST_INSERT_HEAD(swhash, elt, list); 249 elt->tag = page_tag; 250 251 return(elt); 252 } 253 254 /* 255 * uao_find_swslot: find the swap slot number for an aobj/pageidx 256 */ 257 inline static int 258 uao_find_swslot(struct uvm_aobj *aobj, int pageidx) 259 { 260 261 /* if noswap flag is set, then we never return a slot */ 262 if (aobj->u_flags & UAO_FLAG_NOSWAP) 263 return(0); 264 265 /* if hashing, look in hash table. */ 266 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 267 struct uao_swhash_elt *elt = 268 uao_find_swhash_elt(aobj, pageidx, FALSE); 269 270 if (elt) 271 return(UAO_SWHASH_ELT_PAGESLOT(elt, pageidx)); 272 else 273 return(0); 274 } 275 276 /* otherwise, look in the array */ 277 return(aobj->u_swslots[pageidx]); 278 } 279 280 /* 281 * uao_set_swslot: set the swap slot for a page in an aobj. 282 * 283 * => setting a slot to zero frees the slot 284 */ 285 int 286 uao_set_swslot(struct uvm_object *uobj, int pageidx, int slot) 287 { 288 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 289 int oldslot; 290 291 /* if noswap flag is set, then we can't set a slot */ 292 if (aobj->u_flags & UAO_FLAG_NOSWAP) { 293 if (slot == 0) 294 return(0); /* a clear is ok */ 295 296 /* but a set is not */ 297 printf("uao_set_swslot: uobj = %p\n", uobj); 298 panic("uao_set_swslot: attempt to set a slot" 299 " on a NOSWAP object"); 300 } 301 302 /* are we using a hash table? if so, add it in the hash. */ 303 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 304 /* 305 * Avoid allocating an entry just to free it again if 306 * the page had not swap slot in the first place, and 307 * we are freeing. 308 */ 309 struct uao_swhash_elt *elt = 310 uao_find_swhash_elt(aobj, pageidx, slot ? TRUE : FALSE); 311 if (elt == NULL) { 312 KASSERT(slot == 0); 313 return (0); 314 } 315 316 oldslot = UAO_SWHASH_ELT_PAGESLOT(elt, pageidx); 317 UAO_SWHASH_ELT_PAGESLOT(elt, pageidx) = slot; 318 319 /* 320 * now adjust the elt's reference counter and free it if we've 321 * dropped it to zero. 322 */ 323 /* an allocation? */ 324 if (slot) { 325 if (oldslot == 0) 326 elt->count++; 327 } else { /* freeing slot ... */ 328 if (oldslot) /* to be safe */ 329 elt->count--; 330 331 if (elt->count == 0) { 332 LIST_REMOVE(elt, list); 333 pool_put(&uao_swhash_elt_pool, elt); 334 } 335 } 336 } else { 337 /* we are using an array */ 338 oldslot = aobj->u_swslots[pageidx]; 339 aobj->u_swslots[pageidx] = slot; 340 } 341 return (oldslot); 342 } 343 /* 344 * end of hash/array functions 345 */ 346 347 /* 348 * uao_free: free all resources held by an aobj, and then free the aobj 349 * 350 * => the aobj should be dead 351 */ 352 static void 353 uao_free(struct uvm_aobj *aobj) 354 { 355 356 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 357 int i, hashbuckets = aobj->u_swhashmask + 1; 358 359 /* 360 * free the swslots from each hash bucket, 361 * then the hash bucket, and finally the hash table itself. 362 */ 363 for (i = 0; i < hashbuckets; i++) { 364 struct uao_swhash_elt *elt, *next; 365 366 for (elt = LIST_FIRST(&aobj->u_swhash[i]); 367 elt != NULL; 368 elt = next) { 369 int j; 370 371 for (j = 0; j < UAO_SWHASH_CLUSTER_SIZE; j++) { 372 int slot = elt->slots[j]; 373 374 if (slot == 0) { 375 continue; 376 } 377 uvm_swap_free(slot, 1); 378 /* 379 * this page is no longer 380 * only in swap. 381 */ 382 uvmexp.swpgonly--; 383 } 384 385 next = LIST_NEXT(elt, list); 386 pool_put(&uao_swhash_elt_pool, elt); 387 } 388 } 389 390 hashfree(aobj->u_swhash, UAO_SWHASH_BUCKETS(aobj->u_pages), M_UVMAOBJ); 391 } else { 392 int i; 393 394 /* free the array */ 395 for (i = 0; i < aobj->u_pages; i++) { 396 int slot = aobj->u_swslots[i]; 397 398 if (slot) { 399 uvm_swap_free(slot, 1); 400 /* this page is no longer only in swap. */ 401 uvmexp.swpgonly--; 402 } 403 } 404 free(aobj->u_swslots, M_UVMAOBJ, aobj->u_pages * sizeof(int)); 405 } 406 407 /* finally free the aobj itself */ 408 pool_put(&uvm_aobj_pool, aobj); 409 } 410 411 /* 412 * pager functions 413 */ 414 415 /* 416 * Shrink an aobj to a given number of pages. The procedure is always the same: 417 * assess the necessity of data structure conversion (hash to array), secure 418 * resources, flush pages and drop swap slots. 419 * 420 */ 421 422 void 423 uao_shrink_flush(struct uvm_object *uobj, int startpg, int endpg) 424 { 425 KASSERT(startpg < endpg); 426 KASSERT(uobj->uo_refs == 1); 427 uao_flush(uobj, (voff_t)startpg << PAGE_SHIFT, 428 (voff_t)endpg << PAGE_SHIFT, PGO_FREE); 429 uao_dropswap_range(uobj, startpg, endpg); 430 } 431 432 int 433 uao_shrink_hash(struct uvm_object *uobj, int pages) 434 { 435 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 436 struct uao_swhash *new_swhash; 437 struct uao_swhash_elt *elt; 438 unsigned long new_hashmask; 439 int i; 440 441 KASSERT(aobj->u_pages > UAO_SWHASH_THRESHOLD); 442 443 /* 444 * If the size of the hash table doesn't change, all we need to do is 445 * to adjust the page count. 446 */ 447 if (UAO_SWHASH_BUCKETS(aobj->u_pages) == UAO_SWHASH_BUCKETS(pages)) { 448 uao_shrink_flush(uobj, pages, aobj->u_pages); 449 aobj->u_pages = pages; 450 return 0; 451 } 452 453 new_swhash = hashinit(UAO_SWHASH_BUCKETS(pages), M_UVMAOBJ, 454 M_WAITOK | M_CANFAIL, &new_hashmask); 455 if (new_swhash == NULL) 456 return ENOMEM; 457 458 uao_shrink_flush(uobj, pages, aobj->u_pages); 459 460 /* 461 * Even though the hash table size is changing, the hash of the buckets 462 * we are interested in copying should not change. 463 */ 464 for (i = 0; i < UAO_SWHASH_BUCKETS(aobj->u_pages); i++) { 465 while (LIST_EMPTY(&aobj->u_swhash[i]) == 0) { 466 elt = LIST_FIRST(&aobj->u_swhash[i]); 467 LIST_REMOVE(elt, list); 468 LIST_INSERT_HEAD(&new_swhash[i], elt, list); 469 } 470 } 471 472 hashfree(aobj->u_swhash, UAO_SWHASH_BUCKETS(aobj->u_pages), M_UVMAOBJ); 473 474 aobj->u_swhash = new_swhash; 475 aobj->u_pages = pages; 476 aobj->u_swhashmask = new_hashmask; 477 478 return 0; 479 } 480 481 int 482 uao_shrink_convert(struct uvm_object *uobj, int pages) 483 { 484 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 485 struct uao_swhash_elt *elt; 486 int i, *new_swslots; 487 488 new_swslots = mallocarray(pages, sizeof(int), M_UVMAOBJ, 489 M_WAITOK | M_CANFAIL | M_ZERO); 490 if (new_swslots == NULL) 491 return ENOMEM; 492 493 uao_shrink_flush(uobj, pages, aobj->u_pages); 494 495 /* Convert swap slots from hash to array. */ 496 for (i = 0; i < pages; i++) { 497 elt = uao_find_swhash_elt(aobj, i, FALSE); 498 if (elt != NULL) { 499 new_swslots[i] = UAO_SWHASH_ELT_PAGESLOT(elt, i); 500 if (new_swslots[i] != 0) 501 elt->count--; 502 if (elt->count == 0) { 503 LIST_REMOVE(elt, list); 504 pool_put(&uao_swhash_elt_pool, elt); 505 } 506 } 507 } 508 509 hashfree(aobj->u_swhash, UAO_SWHASH_BUCKETS(aobj->u_pages), M_UVMAOBJ); 510 511 aobj->u_swslots = new_swslots; 512 aobj->u_pages = pages; 513 514 return 0; 515 } 516 517 int 518 uao_shrink_array(struct uvm_object *uobj, int pages) 519 { 520 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 521 int i, *new_swslots; 522 523 new_swslots = mallocarray(pages, sizeof(int), M_UVMAOBJ, 524 M_WAITOK | M_CANFAIL | M_ZERO); 525 if (new_swslots == NULL) 526 return ENOMEM; 527 528 uao_shrink_flush(uobj, pages, aobj->u_pages); 529 530 for (i = 0; i < pages; i++) 531 new_swslots[i] = aobj->u_swslots[i]; 532 533 free(aobj->u_swslots, M_UVMAOBJ, aobj->u_pages * sizeof(int)); 534 535 aobj->u_swslots = new_swslots; 536 aobj->u_pages = pages; 537 538 return 0; 539 } 540 541 int 542 uao_shrink(struct uvm_object *uobj, int pages) 543 { 544 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 545 546 KASSERT(pages < aobj->u_pages); 547 548 /* 549 * Distinguish between three possible cases: 550 * 1. aobj uses hash and must be converted to array. 551 * 2. aobj uses array and array size needs to be adjusted. 552 * 3. aobj uses hash and hash size needs to be adjusted. 553 */ 554 if (pages > UAO_SWHASH_THRESHOLD) 555 return uao_shrink_hash(uobj, pages); /* case 3 */ 556 else if (aobj->u_pages > UAO_SWHASH_THRESHOLD) 557 return uao_shrink_convert(uobj, pages); /* case 1 */ 558 else 559 return uao_shrink_array(uobj, pages); /* case 2 */ 560 } 561 562 /* 563 * Grow an aobj to a given number of pages. Right now we only adjust the swap 564 * slots. We could additionally handle page allocation directly, so that they 565 * don't happen through uvm_fault(). That would allow us to use another 566 * mechanism for the swap slots other than malloc(). It is thus mandatory that 567 * the caller of these functions does not allow faults to happen in case of 568 * growth error. 569 */ 570 int 571 uao_grow_array(struct uvm_object *uobj, int pages) 572 { 573 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 574 int i, *new_swslots; 575 576 KASSERT(aobj->u_pages <= UAO_SWHASH_THRESHOLD); 577 578 new_swslots = mallocarray(pages, sizeof(int), M_UVMAOBJ, 579 M_WAITOK | M_CANFAIL | M_ZERO); 580 if (new_swslots == NULL) 581 return ENOMEM; 582 583 for (i = 0; i < aobj->u_pages; i++) 584 new_swslots[i] = aobj->u_swslots[i]; 585 586 free(aobj->u_swslots, M_UVMAOBJ, aobj->u_pages * sizeof(int)); 587 588 aobj->u_swslots = new_swslots; 589 aobj->u_pages = pages; 590 591 return 0; 592 } 593 594 int 595 uao_grow_hash(struct uvm_object *uobj, int pages) 596 { 597 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 598 struct uao_swhash *new_swhash; 599 struct uao_swhash_elt *elt; 600 unsigned long new_hashmask; 601 int i; 602 603 KASSERT(pages > UAO_SWHASH_THRESHOLD); 604 605 /* 606 * If the size of the hash table doesn't change, all we need to do is 607 * to adjust the page count. 608 */ 609 if (UAO_SWHASH_BUCKETS(aobj->u_pages) == UAO_SWHASH_BUCKETS(pages)) { 610 aobj->u_pages = pages; 611 return 0; 612 } 613 614 KASSERT(UAO_SWHASH_BUCKETS(aobj->u_pages) < UAO_SWHASH_BUCKETS(pages)); 615 616 new_swhash = hashinit(UAO_SWHASH_BUCKETS(pages), M_UVMAOBJ, 617 M_WAITOK | M_CANFAIL, &new_hashmask); 618 if (new_swhash == NULL) 619 return ENOMEM; 620 621 for (i = 0; i < UAO_SWHASH_BUCKETS(aobj->u_pages); i++) { 622 while (LIST_EMPTY(&aobj->u_swhash[i]) == 0) { 623 elt = LIST_FIRST(&aobj->u_swhash[i]); 624 LIST_REMOVE(elt, list); 625 LIST_INSERT_HEAD(&new_swhash[i], elt, list); 626 } 627 } 628 629 hashfree(aobj->u_swhash, UAO_SWHASH_BUCKETS(aobj->u_pages), M_UVMAOBJ); 630 631 aobj->u_swhash = new_swhash; 632 aobj->u_pages = pages; 633 aobj->u_swhashmask = new_hashmask; 634 635 return 0; 636 } 637 638 int 639 uao_grow_convert(struct uvm_object *uobj, int pages) 640 { 641 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 642 struct uao_swhash *new_swhash; 643 struct uao_swhash_elt *elt; 644 unsigned long new_hashmask; 645 int i, *old_swslots; 646 647 new_swhash = hashinit(UAO_SWHASH_BUCKETS(pages), M_UVMAOBJ, 648 M_WAITOK | M_CANFAIL, &new_hashmask); 649 if (new_swhash == NULL) 650 return ENOMEM; 651 652 /* Set these now, so we can use uao_find_swhash_elt(). */ 653 old_swslots = aobj->u_swslots; 654 aobj->u_swhash = new_swhash; 655 aobj->u_swhashmask = new_hashmask; 656 657 for (i = 0; i < aobj->u_pages; i++) { 658 if (old_swslots[i] != 0) { 659 elt = uao_find_swhash_elt(aobj, i, TRUE); 660 elt->count++; 661 UAO_SWHASH_ELT_PAGESLOT(elt, i) = old_swslots[i]; 662 } 663 } 664 665 free(old_swslots, M_UVMAOBJ, aobj->u_pages * sizeof(int)); 666 aobj->u_pages = pages; 667 668 return 0; 669 } 670 671 int 672 uao_grow(struct uvm_object *uobj, int pages) 673 { 674 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 675 676 KASSERT(pages > aobj->u_pages); 677 678 /* 679 * Distinguish between three possible cases: 680 * 1. aobj uses hash and hash size needs to be adjusted. 681 * 2. aobj uses array and array size needs to be adjusted. 682 * 3. aobj uses array and must be converted to hash. 683 */ 684 if (pages <= UAO_SWHASH_THRESHOLD) 685 return uao_grow_array(uobj, pages); /* case 2 */ 686 else if (aobj->u_pages > UAO_SWHASH_THRESHOLD) 687 return uao_grow_hash(uobj, pages); /* case 1 */ 688 else 689 return uao_grow_convert(uobj, pages); 690 } 691 692 /* 693 * uao_create: create an aobj of the given size and return its uvm_object. 694 * 695 * => for normal use, flags are zero or UAO_FLAG_CANFAIL. 696 * => for the kernel object, the flags are: 697 * UAO_FLAG_KERNOBJ - allocate the kernel object (can only happen once) 698 * UAO_FLAG_KERNSWAP - enable swapping of kernel object (" ") 699 */ 700 struct uvm_object * 701 uao_create(vsize_t size, int flags) 702 { 703 static struct uvm_aobj kernel_object_store; /* home of kernel_object */ 704 static int kobj_alloced = 0; /* not allocated yet */ 705 int pages = round_page(size) >> PAGE_SHIFT; 706 int refs = UVM_OBJ_KERN; 707 int mflags; 708 struct uvm_aobj *aobj; 709 710 /* malloc a new aobj unless we are asked for the kernel object */ 711 if (flags & UAO_FLAG_KERNOBJ) { /* want kernel object? */ 712 if (kobj_alloced) 713 panic("uao_create: kernel object already allocated"); 714 715 aobj = &kernel_object_store; 716 aobj->u_pages = pages; 717 aobj->u_flags = UAO_FLAG_NOSWAP; /* no swap to start */ 718 /* we are special, we never die */ 719 kobj_alloced = UAO_FLAG_KERNOBJ; 720 } else if (flags & UAO_FLAG_KERNSWAP) { 721 aobj = &kernel_object_store; 722 if (kobj_alloced != UAO_FLAG_KERNOBJ) 723 panic("uao_create: asked to enable swap on kernel object"); 724 kobj_alloced = UAO_FLAG_KERNSWAP; 725 } else { /* normal object */ 726 aobj = pool_get(&uvm_aobj_pool, PR_WAITOK); 727 aobj->u_pages = pages; 728 aobj->u_flags = 0; /* normal object */ 729 refs = 1; /* normal object so 1 ref */ 730 } 731 732 /* allocate hash/array if necessary */ 733 if (flags == 0 || (flags & (UAO_FLAG_KERNSWAP | UAO_FLAG_CANFAIL))) { 734 if (flags) 735 mflags = M_NOWAIT; 736 else 737 mflags = M_WAITOK; 738 739 /* allocate hash table or array depending on object size */ 740 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 741 aobj->u_swhash = hashinit(UAO_SWHASH_BUCKETS(pages), 742 M_UVMAOBJ, mflags, &aobj->u_swhashmask); 743 if (aobj->u_swhash == NULL) { 744 if (flags & UAO_FLAG_CANFAIL) { 745 pool_put(&uvm_aobj_pool, aobj); 746 return (NULL); 747 } 748 panic("uao_create: hashinit swhash failed"); 749 } 750 } else { 751 aobj->u_swslots = mallocarray(pages, sizeof(int), 752 M_UVMAOBJ, mflags|M_ZERO); 753 if (aobj->u_swslots == NULL) { 754 if (flags & UAO_FLAG_CANFAIL) { 755 pool_put(&uvm_aobj_pool, aobj); 756 return (NULL); 757 } 758 panic("uao_create: malloc swslots failed"); 759 } 760 } 761 762 if (flags & UAO_FLAG_KERNSWAP) { 763 aobj->u_flags &= ~UAO_FLAG_NOSWAP; /* clear noswap */ 764 return(&aobj->u_obj); 765 /* done! */ 766 } 767 } 768 769 uvm_objinit(&aobj->u_obj, &aobj_pager, refs); 770 771 /* now that aobj is ready, add it to the global list */ 772 mtx_enter(&uao_list_lock); 773 LIST_INSERT_HEAD(&uao_list, aobj, u_list); 774 mtx_leave(&uao_list_lock); 775 776 return(&aobj->u_obj); 777 } 778 779 780 781 /* 782 * uao_init: set up aobj pager subsystem 783 * 784 * => called at boot time from uvm_pager_init() 785 */ 786 void 787 uao_init(void) 788 { 789 /* 790 * NOTE: Pages for this pool must not come from a pageable 791 * kernel map! 792 */ 793 pool_init(&uao_swhash_elt_pool, sizeof(struct uao_swhash_elt), 0, 794 IPL_NONE, PR_WAITOK, "uaoeltpl", NULL); 795 pool_init(&uvm_aobj_pool, sizeof(struct uvm_aobj), 0, 796 IPL_NONE, PR_WAITOK, "aobjpl", NULL); 797 } 798 799 /* 800 * uao_reference: add a ref to an aobj 801 */ 802 void 803 uao_reference(struct uvm_object *uobj) 804 { 805 KERNEL_ASSERT_LOCKED(); 806 uao_reference_locked(uobj); 807 } 808 809 /* 810 * uao_reference_locked: add a ref to an aobj 811 */ 812 void 813 uao_reference_locked(struct uvm_object *uobj) 814 { 815 816 /* kernel_object already has plenty of references, leave it alone. */ 817 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) 818 return; 819 820 uobj->uo_refs++; /* bump! */ 821 } 822 823 824 /* 825 * uao_detach: drop a reference to an aobj 826 */ 827 void 828 uao_detach(struct uvm_object *uobj) 829 { 830 KERNEL_ASSERT_LOCKED(); 831 uao_detach_locked(uobj); 832 } 833 834 835 /* 836 * uao_detach_locked: drop a reference to an aobj 837 * 838 * => aobj may freed upon return. 839 */ 840 void 841 uao_detach_locked(struct uvm_object *uobj) 842 { 843 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 844 struct vm_page *pg; 845 846 /* detaching from kernel_object is a noop. */ 847 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) { 848 return; 849 } 850 851 uobj->uo_refs--; /* drop ref! */ 852 if (uobj->uo_refs) { /* still more refs? */ 853 return; 854 } 855 856 /* remove the aobj from the global list. */ 857 mtx_enter(&uao_list_lock); 858 LIST_REMOVE(aobj, u_list); 859 mtx_leave(&uao_list_lock); 860 861 /* 862 * Free all pages left in the object. If they're busy, wait 863 * for them to become available before we kill it. 864 * Release swap resources then free the page. 865 */ 866 uvm_lock_pageq(); 867 while((pg = RBT_ROOT(uvm_objtree, &uobj->memt)) != NULL) { 868 if (pg->pg_flags & PG_BUSY) { 869 atomic_setbits_int(&pg->pg_flags, PG_WANTED); 870 uvm_unlock_pageq(); 871 tsleep_nsec(pg, PVM, "uao_det", INFSLP); 872 uvm_lock_pageq(); 873 continue; 874 } 875 pmap_page_protect(pg, PROT_NONE); 876 uao_dropswap(&aobj->u_obj, pg->offset >> PAGE_SHIFT); 877 uvm_pagefree(pg); 878 } 879 uvm_unlock_pageq(); 880 881 /* finally, free the rest. */ 882 uao_free(aobj); 883 } 884 885 /* 886 * uao_flush: "flush" pages out of a uvm object 887 * 888 * => if PGO_CLEANIT is not set, then we will not block. 889 * => if PGO_ALLPAGE is set, then all pages in the object are valid targets 890 * for flushing. 891 * => NOTE: we are allowed to lock the page queues, so the caller 892 * must not be holding the lock on them [e.g. pagedaemon had 893 * better not call us with the queues locked] 894 * => we return TRUE unless we encountered some sort of I/O error 895 * XXXJRT currently never happens, as we never directly initiate 896 * XXXJRT I/O 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 KERNEL_ASSERT_LOCKED(); 906 907 if (flags & PGO_ALLPAGES) { 908 start = 0; 909 stop = (voff_t)aobj->u_pages << PAGE_SHIFT; 910 } else { 911 start = trunc_page(start); 912 stop = round_page(stop); 913 if (stop > ((voff_t)aobj->u_pages << PAGE_SHIFT)) { 914 printf("uao_flush: strange, got an out of range " 915 "flush (fixed)\n"); 916 stop = (voff_t)aobj->u_pages << PAGE_SHIFT; 917 } 918 } 919 920 /* 921 * Don't need to do any work here if we're not freeing 922 * or deactivating pages. 923 */ 924 if ((flags & (PGO_DEACTIVATE|PGO_FREE)) == 0) 925 return (TRUE); 926 927 curoff = start; 928 for (;;) { 929 if (curoff < stop) { 930 pp = uvm_pagelookup(uobj, curoff); 931 curoff += PAGE_SIZE; 932 if (pp == NULL) 933 continue; 934 } else { 935 break; 936 } 937 938 /* Make sure page is unbusy, else wait for it. */ 939 if (pp->pg_flags & PG_BUSY) { 940 atomic_setbits_int(&pp->pg_flags, PG_WANTED); 941 tsleep_nsec(pp, PVM, "uaoflsh", INFSLP); 942 curoff -= PAGE_SIZE; 943 continue; 944 } 945 946 switch (flags & (PGO_CLEANIT|PGO_FREE|PGO_DEACTIVATE)) { 947 /* 948 * XXX In these first 3 cases, we always just 949 * XXX deactivate the page. We may want to 950 * XXX handle the different cases more specifically 951 * XXX in the future. 952 */ 953 case PGO_CLEANIT|PGO_FREE: 954 /* FALLTHROUGH */ 955 case PGO_CLEANIT|PGO_DEACTIVATE: 956 /* FALLTHROUGH */ 957 case PGO_DEACTIVATE: 958 deactivate_it: 959 /* skip the page if it's wired */ 960 if (pp->wire_count != 0) 961 continue; 962 963 uvm_lock_pageq(); 964 /* zap all mappings for the page. */ 965 pmap_page_protect(pp, PROT_NONE); 966 967 /* ...and deactivate the page. */ 968 uvm_pagedeactivate(pp); 969 uvm_unlock_pageq(); 970 971 continue; 972 case PGO_FREE: 973 /* 974 * If there are multiple references to 975 * the object, just deactivate the page. 976 */ 977 if (uobj->uo_refs > 1) 978 goto deactivate_it; 979 980 /* XXX skip the page if it's wired */ 981 if (pp->wire_count != 0) 982 continue; 983 984 /* zap all mappings for the page. */ 985 pmap_page_protect(pp, 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 KERNEL_ASSERT_LOCKED(); 1029 1030 /* get number of pages */ 1031 maxpages = *npagesp; 1032 1033 /* step 1: handled the case where fault data structures are locked. */ 1034 if (flags & PGO_LOCKED) { 1035 /* step 1a: get pages that are already resident. */ 1036 1037 done = TRUE; /* be optimistic */ 1038 gotpages = 0; /* # of pages we got so far */ 1039 1040 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 1041 lcv++, current_offset += PAGE_SIZE) { 1042 /* do we care about this page? if not, skip it */ 1043 if (pps[lcv] == PGO_DONTCARE) 1044 continue; 1045 1046 ptmp = uvm_pagelookup(uobj, current_offset); 1047 1048 /* 1049 * if page is new, attempt to allocate the page, 1050 * zero-fill'd. 1051 */ 1052 if (ptmp == NULL && uao_find_swslot(aobj, 1053 current_offset >> PAGE_SHIFT) == 0) { 1054 ptmp = uvm_pagealloc(uobj, current_offset, 1055 NULL, UVM_PGA_ZERO); 1056 if (ptmp) { 1057 /* new page */ 1058 atomic_clearbits_int(&ptmp->pg_flags, 1059 PG_BUSY|PG_FAKE); 1060 atomic_setbits_int(&ptmp->pg_flags, 1061 PQ_AOBJ); 1062 UVM_PAGE_OWN(ptmp, NULL); 1063 } 1064 } 1065 1066 /* to be useful must get a non-busy page */ 1067 if (ptmp == NULL || 1068 (ptmp->pg_flags & PG_BUSY) != 0) { 1069 if (lcv == centeridx || 1070 (flags & PGO_ALLPAGES) != 0) 1071 /* need to do a wait or I/O! */ 1072 done = FALSE; 1073 continue; 1074 } 1075 1076 /* 1077 * useful page: busy it and plug it in our 1078 * result array 1079 */ 1080 /* caller must un-busy this page */ 1081 atomic_setbits_int(&ptmp->pg_flags, PG_BUSY); 1082 UVM_PAGE_OWN(ptmp, "uao_get1"); 1083 pps[lcv] = ptmp; 1084 gotpages++; 1085 1086 } 1087 1088 /* 1089 * step 1b: now we've either done everything needed or we 1090 * to unlock and do some waiting or I/O. 1091 */ 1092 *npagesp = gotpages; 1093 if (done) 1094 /* bingo! */ 1095 return(VM_PAGER_OK); 1096 else 1097 /* EEK! Need to unlock and I/O */ 1098 return(VM_PAGER_UNLOCK); 1099 } 1100 1101 /* 1102 * step 2: get non-resident or busy pages. 1103 * data structures are unlocked. 1104 */ 1105 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 1106 lcv++, current_offset += PAGE_SIZE) { 1107 /* 1108 * - skip over pages we've already gotten or don't want 1109 * - skip over pages we don't _have_ to get 1110 */ 1111 if (pps[lcv] != NULL || 1112 (lcv != centeridx && (flags & PGO_ALLPAGES) == 0)) 1113 continue; 1114 1115 pageidx = current_offset >> PAGE_SHIFT; 1116 1117 /* 1118 * we have yet to locate the current page (pps[lcv]). we 1119 * first look for a page that is already at the current offset. 1120 * if we find a page, we check to see if it is busy or 1121 * released. if that is the case, then we sleep on the page 1122 * until it is no longer busy or released and repeat the lookup. 1123 * if the page we found is neither busy nor released, then we 1124 * busy it (so we own it) and plug it into pps[lcv]. this 1125 * 'break's the following while loop and indicates we are 1126 * ready to move on to the next page in the "lcv" loop above. 1127 * 1128 * if we exit the while loop with pps[lcv] still set to NULL, 1129 * then it means that we allocated a new busy/fake/clean page 1130 * ptmp in the object and we need to do I/O to fill in the data. 1131 */ 1132 1133 /* top of "pps" while loop */ 1134 while (pps[lcv] == NULL) { 1135 /* look for a resident page */ 1136 ptmp = uvm_pagelookup(uobj, current_offset); 1137 1138 /* not resident? allocate one now (if we can) */ 1139 if (ptmp == NULL) { 1140 1141 ptmp = uvm_pagealloc(uobj, current_offset, 1142 NULL, 0); 1143 1144 /* out of RAM? */ 1145 if (ptmp == NULL) { 1146 uvm_wait("uao_getpage"); 1147 /* goto top of pps while loop */ 1148 continue; 1149 } 1150 1151 /* 1152 * safe with PQ's unlocked: because we just 1153 * alloc'd the page 1154 */ 1155 atomic_setbits_int(&ptmp->pg_flags, PQ_AOBJ); 1156 1157 /* 1158 * got new page ready for I/O. break pps while 1159 * loop. pps[lcv] is still NULL. 1160 */ 1161 break; 1162 } 1163 1164 /* page is there, see if we need to wait on it */ 1165 if ((ptmp->pg_flags & PG_BUSY) != 0) { 1166 atomic_setbits_int(&ptmp->pg_flags, PG_WANTED); 1167 tsleep_nsec(ptmp, PVM, "uao_get", INFSLP); 1168 continue; /* goto top of pps while loop */ 1169 } 1170 1171 /* 1172 * if we get here then the page has become resident and 1173 * unbusy between steps 1 and 2. we busy it now (so we 1174 * own it) and set pps[lcv] (so that we exit the while 1175 * loop). 1176 */ 1177 /* we own it, caller must un-busy */ 1178 atomic_setbits_int(&ptmp->pg_flags, PG_BUSY); 1179 UVM_PAGE_OWN(ptmp, "uao_get2"); 1180 pps[lcv] = ptmp; 1181 } 1182 1183 /* 1184 * if we own the valid page at the correct offset, pps[lcv] will 1185 * point to it. nothing more to do except go to the next page. 1186 */ 1187 if (pps[lcv]) 1188 continue; /* next lcv */ 1189 1190 /* 1191 * we have a "fake/busy/clean" page that we just allocated. 1192 * do the needed "i/o", either reading from swap or zeroing. 1193 */ 1194 swslot = uao_find_swslot(aobj, pageidx); 1195 1196 /* just zero the page if there's nothing in swap. */ 1197 if (swslot == 0) { 1198 /* page hasn't existed before, just zero it. */ 1199 uvm_pagezero(ptmp); 1200 } else { 1201 /* page in the swapped-out page. */ 1202 rv = uvm_swap_get(ptmp, swslot, PGO_SYNCIO); 1203 1204 /* I/O done. check for errors. */ 1205 if (rv != VM_PAGER_OK) { 1206 /* 1207 * remove the swap slot from the aobj 1208 * and mark the aobj as having no real slot. 1209 * don't free the swap slot, thus preventing 1210 * it from being used again. 1211 */ 1212 swslot = uao_set_swslot(&aobj->u_obj, pageidx, 1213 SWSLOT_BAD); 1214 uvm_swap_markbad(swslot, 1); 1215 1216 if (ptmp->pg_flags & PG_WANTED) 1217 wakeup(ptmp); 1218 atomic_clearbits_int(&ptmp->pg_flags, 1219 PG_WANTED|PG_BUSY); 1220 UVM_PAGE_OWN(ptmp, NULL); 1221 uvm_lock_pageq(); 1222 uvm_pagefree(ptmp); 1223 uvm_unlock_pageq(); 1224 1225 return (rv); 1226 } 1227 } 1228 1229 /* 1230 * we got the page! clear the fake flag (indicates valid 1231 * data now in page) and plug into our result array. note 1232 * that page is still busy. 1233 * 1234 * it is the callers job to: 1235 * => check if the page is released 1236 * => unbusy the page 1237 * => activate the page 1238 */ 1239 1240 /* data is valid ... */ 1241 atomic_clearbits_int(&ptmp->pg_flags, PG_FAKE); 1242 pmap_clear_modify(ptmp); /* ... and clean */ 1243 pps[lcv] = ptmp; 1244 1245 } /* lcv loop */ 1246 1247 return(VM_PAGER_OK); 1248 } 1249 1250 /* 1251 * uao_dropswap: release any swap resources from this aobj page. 1252 */ 1253 int 1254 uao_dropswap(struct uvm_object *uobj, int pageidx) 1255 { 1256 int slot; 1257 1258 slot = uao_set_swslot(uobj, pageidx, 0); 1259 if (slot) { 1260 uvm_swap_free(slot, 1); 1261 } 1262 return (slot); 1263 } 1264 1265 /* 1266 * page in every page in every aobj that is paged-out to a range of swslots. 1267 * 1268 * => returns TRUE if pagein was aborted due to lack of memory. 1269 */ 1270 boolean_t 1271 uao_swap_off(int startslot, int endslot) 1272 { 1273 struct uvm_aobj *aobj, *nextaobj, *prevaobj = NULL; 1274 1275 /* walk the list of all aobjs. */ 1276 mtx_enter(&uao_list_lock); 1277 1278 for (aobj = LIST_FIRST(&uao_list); 1279 aobj != NULL; 1280 aobj = nextaobj) { 1281 boolean_t rv; 1282 1283 /* 1284 * add a ref to the aobj so it doesn't disappear 1285 * while we're working. 1286 */ 1287 uao_reference_locked(&aobj->u_obj); 1288 1289 /* 1290 * now it's safe to unlock the uao list. 1291 * note that lock interleaving is alright with IPL_NONE mutexes. 1292 */ 1293 mtx_leave(&uao_list_lock); 1294 1295 if (prevaobj) { 1296 uao_detach_locked(&prevaobj->u_obj); 1297 prevaobj = NULL; 1298 } 1299 1300 /* 1301 * page in any pages in the swslot range. 1302 * if there's an error, abort and return the error. 1303 */ 1304 rv = uao_pagein(aobj, startslot, endslot); 1305 if (rv) { 1306 uao_detach_locked(&aobj->u_obj); 1307 return rv; 1308 } 1309 1310 /* 1311 * we're done with this aobj. 1312 * relock the list and drop our ref on the aobj. 1313 */ 1314 mtx_enter(&uao_list_lock); 1315 nextaobj = LIST_NEXT(aobj, u_list); 1316 /* 1317 * prevaobj means that we have an object that we need 1318 * to drop a reference for. We can't just drop it now with 1319 * the list locked since that could cause lock recursion in 1320 * the case where we reduce the refcount to 0. It will be 1321 * released the next time we drop the list lock. 1322 */ 1323 prevaobj = aobj; 1324 } 1325 1326 /* done with traversal, unlock the list */ 1327 mtx_leave(&uao_list_lock); 1328 if (prevaobj) { 1329 uao_detach_locked(&prevaobj->u_obj); 1330 } 1331 return FALSE; 1332 } 1333 1334 /* 1335 * page in any pages from aobj in the given range. 1336 * 1337 * => returns TRUE if pagein was aborted due to lack of memory. 1338 */ 1339 static boolean_t 1340 uao_pagein(struct uvm_aobj *aobj, int startslot, int endslot) 1341 { 1342 boolean_t rv; 1343 1344 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 1345 struct uao_swhash_elt *elt; 1346 int bucket; 1347 1348 restart: 1349 for (bucket = aobj->u_swhashmask; bucket >= 0; bucket--) { 1350 for (elt = LIST_FIRST(&aobj->u_swhash[bucket]); 1351 elt != NULL; 1352 elt = LIST_NEXT(elt, list)) { 1353 int i; 1354 1355 for (i = 0; i < UAO_SWHASH_CLUSTER_SIZE; i++) { 1356 int slot = elt->slots[i]; 1357 1358 /* if slot isn't in range, skip it. */ 1359 if (slot < startslot || 1360 slot >= endslot) { 1361 continue; 1362 } 1363 1364 /* 1365 * process the page, 1366 * the start over on this object 1367 * since the swhash elt 1368 * may have been freed. 1369 */ 1370 rv = uao_pagein_page(aobj, 1371 UAO_SWHASH_ELT_PAGEIDX_BASE(elt) + i); 1372 if (rv) { 1373 return rv; 1374 } 1375 goto restart; 1376 } 1377 } 1378 } 1379 } else { 1380 int i; 1381 1382 for (i = 0; i < aobj->u_pages; i++) { 1383 int slot = aobj->u_swslots[i]; 1384 1385 /* if the slot isn't in range, skip it */ 1386 if (slot < startslot || slot >= endslot) { 1387 continue; 1388 } 1389 1390 /* process the page. */ 1391 rv = uao_pagein_page(aobj, i); 1392 if (rv) { 1393 return rv; 1394 } 1395 } 1396 } 1397 1398 return FALSE; 1399 } 1400 1401 /* 1402 * page in a page from an aobj. used for swap_off. 1403 * returns TRUE if pagein was aborted due to lack of memory. 1404 */ 1405 static boolean_t 1406 uao_pagein_page(struct uvm_aobj *aobj, int pageidx) 1407 { 1408 struct vm_page *pg; 1409 int rv, slot, npages; 1410 1411 pg = NULL; 1412 npages = 1; 1413 rv = uao_get(&aobj->u_obj, (voff_t)pageidx << PAGE_SHIFT, 1414 &pg, &npages, 0, PROT_READ | PROT_WRITE, 0, 0); 1415 1416 switch (rv) { 1417 case VM_PAGER_OK: 1418 break; 1419 1420 case VM_PAGER_ERROR: 1421 case VM_PAGER_REFAULT: 1422 /* 1423 * nothing more to do on errors. 1424 * VM_PAGER_REFAULT can only mean that the anon was freed, 1425 * so again there's nothing to do. 1426 */ 1427 return FALSE; 1428 } 1429 1430 /* 1431 * ok, we've got the page now. 1432 * mark it as dirty, clear its swslot and un-busy it. 1433 */ 1434 slot = uao_set_swslot(&aobj->u_obj, pageidx, 0); 1435 uvm_swap_free(slot, 1); 1436 atomic_clearbits_int(&pg->pg_flags, PG_BUSY|PG_CLEAN|PG_FAKE); 1437 UVM_PAGE_OWN(pg, NULL); 1438 1439 /* deactivate the page (to put it on a page queue). */ 1440 pmap_clear_reference(pg); 1441 uvm_lock_pageq(); 1442 uvm_pagedeactivate(pg); 1443 uvm_unlock_pageq(); 1444 1445 return FALSE; 1446 } 1447 1448 /* 1449 * XXX pedro: Once we are comfortable enough with this function, we can adapt 1450 * uao_free() to use it. 1451 * 1452 * uao_dropswap_range: drop swapslots in the range. 1453 * 1454 * => aobj must be locked and is returned locked. 1455 * => start is inclusive. end is exclusive. 1456 */ 1457 void 1458 uao_dropswap_range(struct uvm_object *uobj, voff_t start, voff_t end) 1459 { 1460 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 1461 int swpgonlydelta = 0; 1462 1463 /* KASSERT(mutex_owned(uobj->vmobjlock)); */ 1464 1465 if (end == 0) { 1466 end = INT64_MAX; 1467 } 1468 1469 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 1470 int i, hashbuckets = aobj->u_swhashmask + 1; 1471 voff_t taghi; 1472 voff_t taglo; 1473 1474 taglo = UAO_SWHASH_ELT_TAG(start); 1475 taghi = UAO_SWHASH_ELT_TAG(end); 1476 1477 for (i = 0; i < hashbuckets; i++) { 1478 struct uao_swhash_elt *elt, *next; 1479 1480 for (elt = LIST_FIRST(&aobj->u_swhash[i]); 1481 elt != NULL; 1482 elt = next) { 1483 int startidx, endidx; 1484 int j; 1485 1486 next = LIST_NEXT(elt, list); 1487 1488 if (elt->tag < taglo || taghi < elt->tag) { 1489 continue; 1490 } 1491 1492 if (elt->tag == taglo) { 1493 startidx = 1494 UAO_SWHASH_ELT_PAGESLOT_IDX(start); 1495 } else { 1496 startidx = 0; 1497 } 1498 1499 if (elt->tag == taghi) { 1500 endidx = 1501 UAO_SWHASH_ELT_PAGESLOT_IDX(end); 1502 } else { 1503 endidx = UAO_SWHASH_CLUSTER_SIZE; 1504 } 1505 1506 for (j = startidx; j < endidx; j++) { 1507 int slot = elt->slots[j]; 1508 1509 KASSERT(uvm_pagelookup(&aobj->u_obj, 1510 (voff_t)(UAO_SWHASH_ELT_PAGEIDX_BASE(elt) 1511 + j) << PAGE_SHIFT) == NULL); 1512 1513 if (slot > 0) { 1514 uvm_swap_free(slot, 1); 1515 swpgonlydelta++; 1516 KASSERT(elt->count > 0); 1517 elt->slots[j] = 0; 1518 elt->count--; 1519 } 1520 } 1521 1522 if (elt->count == 0) { 1523 LIST_REMOVE(elt, list); 1524 pool_put(&uao_swhash_elt_pool, elt); 1525 } 1526 } 1527 } 1528 } else { 1529 int i; 1530 1531 if (aobj->u_pages < end) { 1532 end = aobj->u_pages; 1533 } 1534 for (i = start; i < end; i++) { 1535 int slot = aobj->u_swslots[i]; 1536 1537 if (slot > 0) { 1538 uvm_swap_free(slot, 1); 1539 swpgonlydelta++; 1540 } 1541 } 1542 } 1543 1544 /* 1545 * adjust the counter of pages only in swap for all 1546 * the swap slots we've freed. 1547 */ 1548 if (swpgonlydelta > 0) { 1549 KASSERT(uvmexp.swpgonly >= swpgonlydelta); 1550 uvmexp.swpgonly -= swpgonlydelta; 1551 } 1552 } 1553