1 /* $OpenBSD: uvm_aobj.c,v 1.87 2020/09/22 14:31:08 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 struct uvm_pagerops aobj_pager = { 188 NULL, /* init */ 189 uao_reference, /* reference */ 190 uao_detach, /* detach */ 191 NULL, /* fault */ 192 uao_flush, /* flush */ 193 uao_get, /* get */ 194 }; 195 196 /* 197 * uao_list: global list of active aobjs, locked by uao_list_lock 198 * 199 * Lock ordering: generally the locking order is object lock, then list lock. 200 * in the case of swap off we have to iterate over the list, and thus the 201 * ordering is reversed. In that case we must use trylocking to prevent 202 * deadlock. 203 */ 204 static LIST_HEAD(aobjlist, uvm_aobj) uao_list = LIST_HEAD_INITIALIZER(uao_list); 205 static struct mutex uao_list_lock = MUTEX_INITIALIZER(IPL_NONE); 206 207 208 /* 209 * functions 210 */ 211 /* 212 * hash table/array related functions 213 */ 214 /* 215 * uao_find_swhash_elt: find (or create) a hash table entry for a page 216 * offset. 217 */ 218 static struct uao_swhash_elt * 219 uao_find_swhash_elt(struct uvm_aobj *aobj, int pageidx, boolean_t create) 220 { 221 struct uao_swhash *swhash; 222 struct uao_swhash_elt *elt; 223 voff_t page_tag; 224 225 swhash = UAO_SWHASH_HASH(aobj, pageidx); /* first hash to get bucket */ 226 page_tag = UAO_SWHASH_ELT_TAG(pageidx); /* tag to search for */ 227 228 /* now search the bucket for the requested tag */ 229 LIST_FOREACH(elt, swhash, list) { 230 if (elt->tag == page_tag) 231 return(elt); 232 } 233 234 /* fail now if we are not allowed to create a new entry in the bucket */ 235 if (!create) 236 return NULL; 237 238 /* allocate a new entry for the bucket and init/insert it in */ 239 elt = pool_get(&uao_swhash_elt_pool, PR_NOWAIT | PR_ZERO); 240 /* 241 * XXX We cannot sleep here as the hash table might disappear 242 * from under our feet. And we run the risk of deadlocking 243 * the pagedeamon. In fact this code will only be called by 244 * the pagedaemon and allocation will only fail if we 245 * exhausted the pagedeamon reserve. In that case we're 246 * doomed anyway, so panic. 247 */ 248 if (elt == NULL) 249 panic("%s: can't allocate entry", __func__); 250 LIST_INSERT_HEAD(swhash, elt, list); 251 elt->tag = page_tag; 252 253 return(elt); 254 } 255 256 /* 257 * uao_find_swslot: find the swap slot number for an aobj/pageidx 258 */ 259 inline static int 260 uao_find_swslot(struct uvm_aobj *aobj, int pageidx) 261 { 262 263 /* if noswap flag is set, then we never return a slot */ 264 if (aobj->u_flags & UAO_FLAG_NOSWAP) 265 return(0); 266 267 /* if hashing, look in hash table. */ 268 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 269 struct uao_swhash_elt *elt = 270 uao_find_swhash_elt(aobj, pageidx, FALSE); 271 272 if (elt) 273 return(UAO_SWHASH_ELT_PAGESLOT(elt, pageidx)); 274 else 275 return(0); 276 } 277 278 /* otherwise, look in the array */ 279 return(aobj->u_swslots[pageidx]); 280 } 281 282 /* 283 * uao_set_swslot: set the swap slot for a page in an aobj. 284 * 285 * => setting a slot to zero frees the slot 286 */ 287 int 288 uao_set_swslot(struct uvm_object *uobj, int pageidx, int slot) 289 { 290 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 291 int oldslot; 292 293 /* if noswap flag is set, then we can't set a slot */ 294 if (aobj->u_flags & UAO_FLAG_NOSWAP) { 295 if (slot == 0) 296 return(0); /* a clear is ok */ 297 298 /* but a set is not */ 299 printf("uao_set_swslot: uobj = %p\n", uobj); 300 panic("uao_set_swslot: attempt to set a slot" 301 " on a NOSWAP object"); 302 } 303 304 /* are we using a hash table? if so, add it in the hash. */ 305 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 306 /* 307 * Avoid allocating an entry just to free it again if 308 * the page had not swap slot in the first place, and 309 * we are freeing. 310 */ 311 struct uao_swhash_elt *elt = 312 uao_find_swhash_elt(aobj, pageidx, slot ? TRUE : FALSE); 313 if (elt == NULL) { 314 KASSERT(slot == 0); 315 return (0); 316 } 317 318 oldslot = UAO_SWHASH_ELT_PAGESLOT(elt, pageidx); 319 UAO_SWHASH_ELT_PAGESLOT(elt, pageidx) = slot; 320 321 /* 322 * now adjust the elt's reference counter and free it if we've 323 * dropped it to zero. 324 */ 325 /* an allocation? */ 326 if (slot) { 327 if (oldslot == 0) 328 elt->count++; 329 } else { /* freeing slot ... */ 330 if (oldslot) /* to be safe */ 331 elt->count--; 332 333 if (elt->count == 0) { 334 LIST_REMOVE(elt, list); 335 pool_put(&uao_swhash_elt_pool, elt); 336 } 337 } 338 } else { 339 /* we are using an array */ 340 oldslot = aobj->u_swslots[pageidx]; 341 aobj->u_swslots[pageidx] = slot; 342 } 343 return (oldslot); 344 } 345 /* 346 * end of hash/array functions 347 */ 348 349 /* 350 * uao_free: free all resources held by an aobj, and then free the aobj 351 * 352 * => the aobj should be dead 353 */ 354 static void 355 uao_free(struct uvm_aobj *aobj) 356 { 357 358 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 359 int i, hashbuckets = aobj->u_swhashmask + 1; 360 361 /* 362 * free the swslots from each hash bucket, 363 * then the hash bucket, and finally the hash table itself. 364 */ 365 for (i = 0; i < hashbuckets; i++) { 366 struct uao_swhash_elt *elt, *next; 367 368 for (elt = LIST_FIRST(&aobj->u_swhash[i]); 369 elt != NULL; 370 elt = next) { 371 int j; 372 373 for (j = 0; j < UAO_SWHASH_CLUSTER_SIZE; j++) { 374 int slot = elt->slots[j]; 375 376 if (slot == 0) { 377 continue; 378 } 379 uvm_swap_free(slot, 1); 380 /* 381 * this page is no longer 382 * only in swap. 383 */ 384 uvmexp.swpgonly--; 385 } 386 387 next = LIST_NEXT(elt, list); 388 pool_put(&uao_swhash_elt_pool, elt); 389 } 390 } 391 392 hashfree(aobj->u_swhash, UAO_SWHASH_BUCKETS(aobj->u_pages), M_UVMAOBJ); 393 } else { 394 int i; 395 396 /* free the array */ 397 for (i = 0; i < aobj->u_pages; i++) { 398 int slot = aobj->u_swslots[i]; 399 400 if (slot) { 401 uvm_swap_free(slot, 1); 402 /* this page is no longer only in swap. */ 403 uvmexp.swpgonly--; 404 } 405 } 406 free(aobj->u_swslots, M_UVMAOBJ, aobj->u_pages * sizeof(int)); 407 } 408 409 /* finally free the aobj itself */ 410 pool_put(&uvm_aobj_pool, aobj); 411 } 412 413 /* 414 * pager functions 415 */ 416 417 /* 418 * Shrink an aobj to a given number of pages. The procedure is always the same: 419 * assess the necessity of data structure conversion (hash to array), secure 420 * resources, flush pages and drop swap slots. 421 * 422 */ 423 424 void 425 uao_shrink_flush(struct uvm_object *uobj, int startpg, int endpg) 426 { 427 KASSERT(startpg < endpg); 428 KASSERT(uobj->uo_refs == 1); 429 uao_flush(uobj, (voff_t)startpg << PAGE_SHIFT, 430 (voff_t)endpg << PAGE_SHIFT, PGO_FREE); 431 uao_dropswap_range(uobj, startpg, endpg); 432 } 433 434 int 435 uao_shrink_hash(struct uvm_object *uobj, int pages) 436 { 437 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 438 struct uao_swhash *new_swhash; 439 struct uao_swhash_elt *elt; 440 unsigned long new_hashmask; 441 int i; 442 443 KASSERT(aobj->u_pages > UAO_SWHASH_THRESHOLD); 444 445 /* 446 * If the size of the hash table doesn't change, all we need to do is 447 * to adjust the page count. 448 */ 449 if (UAO_SWHASH_BUCKETS(aobj->u_pages) == UAO_SWHASH_BUCKETS(pages)) { 450 uao_shrink_flush(uobj, pages, aobj->u_pages); 451 aobj->u_pages = pages; 452 return 0; 453 } 454 455 new_swhash = hashinit(UAO_SWHASH_BUCKETS(pages), M_UVMAOBJ, 456 M_WAITOK | M_CANFAIL, &new_hashmask); 457 if (new_swhash == NULL) 458 return ENOMEM; 459 460 uao_shrink_flush(uobj, pages, aobj->u_pages); 461 462 /* 463 * Even though the hash table size is changing, the hash of the buckets 464 * we are interested in copying should not change. 465 */ 466 for (i = 0; i < UAO_SWHASH_BUCKETS(aobj->u_pages); i++) { 467 while (LIST_EMPTY(&aobj->u_swhash[i]) == 0) { 468 elt = LIST_FIRST(&aobj->u_swhash[i]); 469 LIST_REMOVE(elt, list); 470 LIST_INSERT_HEAD(&new_swhash[i], elt, list); 471 } 472 } 473 474 hashfree(aobj->u_swhash, UAO_SWHASH_BUCKETS(aobj->u_pages), M_UVMAOBJ); 475 476 aobj->u_swhash = new_swhash; 477 aobj->u_pages = pages; 478 aobj->u_swhashmask = new_hashmask; 479 480 return 0; 481 } 482 483 int 484 uao_shrink_convert(struct uvm_object *uobj, int pages) 485 { 486 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 487 struct uao_swhash_elt *elt; 488 int i, *new_swslots; 489 490 new_swslots = mallocarray(pages, sizeof(int), M_UVMAOBJ, 491 M_WAITOK | M_CANFAIL | M_ZERO); 492 if (new_swslots == NULL) 493 return ENOMEM; 494 495 uao_shrink_flush(uobj, pages, aobj->u_pages); 496 497 /* Convert swap slots from hash to array. */ 498 for (i = 0; i < pages; i++) { 499 elt = uao_find_swhash_elt(aobj, i, FALSE); 500 if (elt != NULL) { 501 new_swslots[i] = UAO_SWHASH_ELT_PAGESLOT(elt, i); 502 if (new_swslots[i] != 0) 503 elt->count--; 504 if (elt->count == 0) { 505 LIST_REMOVE(elt, list); 506 pool_put(&uao_swhash_elt_pool, elt); 507 } 508 } 509 } 510 511 hashfree(aobj->u_swhash, UAO_SWHASH_BUCKETS(aobj->u_pages), M_UVMAOBJ); 512 513 aobj->u_swslots = new_swslots; 514 aobj->u_pages = pages; 515 516 return 0; 517 } 518 519 int 520 uao_shrink_array(struct uvm_object *uobj, int pages) 521 { 522 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 523 int i, *new_swslots; 524 525 new_swslots = mallocarray(pages, sizeof(int), M_UVMAOBJ, 526 M_WAITOK | M_CANFAIL | M_ZERO); 527 if (new_swslots == NULL) 528 return ENOMEM; 529 530 uao_shrink_flush(uobj, pages, aobj->u_pages); 531 532 for (i = 0; i < pages; i++) 533 new_swslots[i] = aobj->u_swslots[i]; 534 535 free(aobj->u_swslots, M_UVMAOBJ, aobj->u_pages * sizeof(int)); 536 537 aobj->u_swslots = new_swslots; 538 aobj->u_pages = pages; 539 540 return 0; 541 } 542 543 int 544 uao_shrink(struct uvm_object *uobj, int pages) 545 { 546 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 547 548 KASSERT(pages < aobj->u_pages); 549 550 /* 551 * Distinguish between three possible cases: 552 * 1. aobj uses hash and must be converted to array. 553 * 2. aobj uses array and array size needs to be adjusted. 554 * 3. aobj uses hash and hash size needs to be adjusted. 555 */ 556 if (pages > UAO_SWHASH_THRESHOLD) 557 return uao_shrink_hash(uobj, pages); /* case 3 */ 558 else if (aobj->u_pages > UAO_SWHASH_THRESHOLD) 559 return uao_shrink_convert(uobj, pages); /* case 1 */ 560 else 561 return uao_shrink_array(uobj, pages); /* case 2 */ 562 } 563 564 /* 565 * Grow an aobj to a given number of pages. Right now we only adjust the swap 566 * slots. We could additionally handle page allocation directly, so that they 567 * don't happen through uvm_fault(). That would allow us to use another 568 * mechanism for the swap slots other than malloc(). It is thus mandatory that 569 * the caller of these functions does not allow faults to happen in case of 570 * growth error. 571 */ 572 int 573 uao_grow_array(struct uvm_object *uobj, int pages) 574 { 575 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 576 int i, *new_swslots; 577 578 KASSERT(aobj->u_pages <= UAO_SWHASH_THRESHOLD); 579 580 new_swslots = mallocarray(pages, sizeof(int), M_UVMAOBJ, 581 M_WAITOK | M_CANFAIL | M_ZERO); 582 if (new_swslots == NULL) 583 return ENOMEM; 584 585 for (i = 0; i < aobj->u_pages; i++) 586 new_swslots[i] = aobj->u_swslots[i]; 587 588 free(aobj->u_swslots, M_UVMAOBJ, aobj->u_pages * sizeof(int)); 589 590 aobj->u_swslots = new_swslots; 591 aobj->u_pages = pages; 592 593 return 0; 594 } 595 596 int 597 uao_grow_hash(struct uvm_object *uobj, int pages) 598 { 599 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 600 struct uao_swhash *new_swhash; 601 struct uao_swhash_elt *elt; 602 unsigned long new_hashmask; 603 int i; 604 605 KASSERT(pages > UAO_SWHASH_THRESHOLD); 606 607 /* 608 * If the size of the hash table doesn't change, all we need to do is 609 * to adjust the page count. 610 */ 611 if (UAO_SWHASH_BUCKETS(aobj->u_pages) == UAO_SWHASH_BUCKETS(pages)) { 612 aobj->u_pages = pages; 613 return 0; 614 } 615 616 KASSERT(UAO_SWHASH_BUCKETS(aobj->u_pages) < UAO_SWHASH_BUCKETS(pages)); 617 618 new_swhash = hashinit(UAO_SWHASH_BUCKETS(pages), M_UVMAOBJ, 619 M_WAITOK | M_CANFAIL, &new_hashmask); 620 if (new_swhash == NULL) 621 return ENOMEM; 622 623 for (i = 0; i < UAO_SWHASH_BUCKETS(aobj->u_pages); i++) { 624 while (LIST_EMPTY(&aobj->u_swhash[i]) == 0) { 625 elt = LIST_FIRST(&aobj->u_swhash[i]); 626 LIST_REMOVE(elt, list); 627 LIST_INSERT_HEAD(&new_swhash[i], elt, list); 628 } 629 } 630 631 hashfree(aobj->u_swhash, UAO_SWHASH_BUCKETS(aobj->u_pages), M_UVMAOBJ); 632 633 aobj->u_swhash = new_swhash; 634 aobj->u_pages = pages; 635 aobj->u_swhashmask = new_hashmask; 636 637 return 0; 638 } 639 640 int 641 uao_grow_convert(struct uvm_object *uobj, int pages) 642 { 643 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 644 struct uao_swhash *new_swhash; 645 struct uao_swhash_elt *elt; 646 unsigned long new_hashmask; 647 int i, *old_swslots; 648 649 new_swhash = hashinit(UAO_SWHASH_BUCKETS(pages), M_UVMAOBJ, 650 M_WAITOK | M_CANFAIL, &new_hashmask); 651 if (new_swhash == NULL) 652 return ENOMEM; 653 654 /* Set these now, so we can use uao_find_swhash_elt(). */ 655 old_swslots = aobj->u_swslots; 656 aobj->u_swhash = new_swhash; 657 aobj->u_swhashmask = new_hashmask; 658 659 for (i = 0; i < aobj->u_pages; i++) { 660 if (old_swslots[i] != 0) { 661 elt = uao_find_swhash_elt(aobj, i, TRUE); 662 elt->count++; 663 UAO_SWHASH_ELT_PAGESLOT(elt, i) = old_swslots[i]; 664 } 665 } 666 667 free(old_swslots, M_UVMAOBJ, aobj->u_pages * sizeof(int)); 668 aobj->u_pages = pages; 669 670 return 0; 671 } 672 673 int 674 uao_grow(struct uvm_object *uobj, int pages) 675 { 676 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 677 678 KASSERT(pages > aobj->u_pages); 679 680 /* 681 * Distinguish between three possible cases: 682 * 1. aobj uses hash and hash size needs to be adjusted. 683 * 2. aobj uses array and array size needs to be adjusted. 684 * 3. aobj uses array and must be converted to hash. 685 */ 686 if (pages <= UAO_SWHASH_THRESHOLD) 687 return uao_grow_array(uobj, pages); /* case 2 */ 688 else if (aobj->u_pages > UAO_SWHASH_THRESHOLD) 689 return uao_grow_hash(uobj, pages); /* case 1 */ 690 else 691 return uao_grow_convert(uobj, pages); 692 } 693 694 /* 695 * uao_create: create an aobj of the given size and return its uvm_object. 696 * 697 * => for normal use, flags are zero or UAO_FLAG_CANFAIL. 698 * => for the kernel object, the flags are: 699 * UAO_FLAG_KERNOBJ - allocate the kernel object (can only happen once) 700 * UAO_FLAG_KERNSWAP - enable swapping of kernel object (" ") 701 */ 702 struct uvm_object * 703 uao_create(vsize_t size, int flags) 704 { 705 static struct uvm_aobj kernel_object_store; /* home of kernel_object */ 706 static int kobj_alloced = 0; /* not allocated yet */ 707 int pages = round_page(size) >> PAGE_SHIFT; 708 int refs = UVM_OBJ_KERN; 709 int mflags; 710 struct uvm_aobj *aobj; 711 712 /* malloc a new aobj unless we are asked for the kernel object */ 713 if (flags & UAO_FLAG_KERNOBJ) { /* want kernel object? */ 714 if (kobj_alloced) 715 panic("uao_create: kernel object already allocated"); 716 717 aobj = &kernel_object_store; 718 aobj->u_pages = pages; 719 aobj->u_flags = UAO_FLAG_NOSWAP; /* no swap to start */ 720 /* we are special, we never die */ 721 kobj_alloced = UAO_FLAG_KERNOBJ; 722 } else if (flags & UAO_FLAG_KERNSWAP) { 723 aobj = &kernel_object_store; 724 if (kobj_alloced != UAO_FLAG_KERNOBJ) 725 panic("uao_create: asked to enable swap on kernel object"); 726 kobj_alloced = UAO_FLAG_KERNSWAP; 727 } else { /* normal object */ 728 aobj = pool_get(&uvm_aobj_pool, PR_WAITOK); 729 aobj->u_pages = pages; 730 aobj->u_flags = 0; /* normal object */ 731 refs = 1; /* normal object so 1 ref */ 732 } 733 734 /* allocate hash/array if necessary */ 735 if (flags == 0 || (flags & (UAO_FLAG_KERNSWAP | UAO_FLAG_CANFAIL))) { 736 if (flags) 737 mflags = M_NOWAIT; 738 else 739 mflags = M_WAITOK; 740 741 /* allocate hash table or array depending on object size */ 742 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 743 aobj->u_swhash = hashinit(UAO_SWHASH_BUCKETS(pages), 744 M_UVMAOBJ, mflags, &aobj->u_swhashmask); 745 if (aobj->u_swhash == NULL) { 746 if (flags & UAO_FLAG_CANFAIL) { 747 pool_put(&uvm_aobj_pool, aobj); 748 return (NULL); 749 } 750 panic("uao_create: hashinit swhash failed"); 751 } 752 } else { 753 aobj->u_swslots = mallocarray(pages, sizeof(int), 754 M_UVMAOBJ, mflags|M_ZERO); 755 if (aobj->u_swslots == NULL) { 756 if (flags & UAO_FLAG_CANFAIL) { 757 pool_put(&uvm_aobj_pool, aobj); 758 return (NULL); 759 } 760 panic("uao_create: malloc swslots failed"); 761 } 762 } 763 764 if (flags & UAO_FLAG_KERNSWAP) { 765 aobj->u_flags &= ~UAO_FLAG_NOSWAP; /* clear noswap */ 766 return(&aobj->u_obj); 767 /* done! */ 768 } 769 } 770 771 uvm_objinit(&aobj->u_obj, &aobj_pager, refs); 772 773 /* now that aobj is ready, add it to the global list */ 774 mtx_enter(&uao_list_lock); 775 LIST_INSERT_HEAD(&uao_list, aobj, u_list); 776 mtx_leave(&uao_list_lock); 777 778 return(&aobj->u_obj); 779 } 780 781 782 783 /* 784 * uao_init: set up aobj pager subsystem 785 * 786 * => called at boot time from uvm_pager_init() 787 */ 788 void 789 uao_init(void) 790 { 791 static int uao_initialized; 792 793 if (uao_initialized) 794 return; 795 uao_initialized = TRUE; 796 797 /* 798 * NOTE: Pages for this pool must not come from a pageable 799 * kernel map! 800 */ 801 pool_init(&uao_swhash_elt_pool, sizeof(struct uao_swhash_elt), 0, 802 IPL_NONE, PR_WAITOK, "uaoeltpl", NULL); 803 pool_init(&uvm_aobj_pool, sizeof(struct uvm_aobj), 0, 804 IPL_NONE, PR_WAITOK, "aobjpl", NULL); 805 } 806 807 /* 808 * uao_reference: add a ref to an aobj 809 */ 810 void 811 uao_reference(struct uvm_object *uobj) 812 { 813 uao_reference_locked(uobj); 814 } 815 816 /* 817 * uao_reference_locked: add a ref to an aobj 818 */ 819 void 820 uao_reference_locked(struct uvm_object *uobj) 821 { 822 823 /* kernel_object already has plenty of references, leave it alone. */ 824 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) 825 return; 826 827 uobj->uo_refs++; /* bump! */ 828 } 829 830 831 /* 832 * uao_detach: drop a reference to an aobj 833 */ 834 void 835 uao_detach(struct uvm_object *uobj) 836 { 837 uao_detach_locked(uobj); 838 } 839 840 841 /* 842 * uao_detach_locked: drop a reference to an aobj 843 * 844 * => aobj may freed upon return. 845 */ 846 void 847 uao_detach_locked(struct uvm_object *uobj) 848 { 849 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 850 struct vm_page *pg; 851 852 /* detaching from kernel_object is a noop. */ 853 if (UVM_OBJ_IS_KERN_OBJECT(uobj)) { 854 return; 855 } 856 857 uobj->uo_refs--; /* drop ref! */ 858 if (uobj->uo_refs) { /* still more refs? */ 859 return; 860 } 861 862 /* remove the aobj from the global list. */ 863 mtx_enter(&uao_list_lock); 864 LIST_REMOVE(aobj, u_list); 865 mtx_leave(&uao_list_lock); 866 867 /* 868 * Free all pages left in the object. If they're busy, wait 869 * for them to become available before we kill it. 870 * Release swap resources then free the page. 871 */ 872 uvm_lock_pageq(); 873 while((pg = RBT_ROOT(uvm_objtree, &uobj->memt)) != NULL) { 874 if (pg->pg_flags & PG_BUSY) { 875 atomic_setbits_int(&pg->pg_flags, PG_WANTED); 876 uvm_unlock_pageq(); 877 tsleep_nsec(pg, PVM, "uao_det", INFSLP); 878 uvm_lock_pageq(); 879 continue; 880 } 881 pmap_page_protect(pg, PROT_NONE); 882 uao_dropswap(&aobj->u_obj, pg->offset >> PAGE_SHIFT); 883 uvm_pagefree(pg); 884 } 885 uvm_unlock_pageq(); 886 887 /* finally, free the rest. */ 888 uao_free(aobj); 889 } 890 891 /* 892 * uao_flush: "flush" pages out of a uvm object 893 * 894 * => if PGO_CLEANIT is not set, then we will not block. 895 * => if PGO_ALLPAGE is set, then all pages in the object are valid targets 896 * for flushing. 897 * => NOTE: we are allowed to lock the page queues, so the caller 898 * must not be holding the lock on them [e.g. pagedaemon had 899 * better not call us with the queues locked] 900 * => we return TRUE unless we encountered some sort of I/O error 901 * XXXJRT currently never happens, as we never directly initiate 902 * XXXJRT I/O 903 */ 904 boolean_t 905 uao_flush(struct uvm_object *uobj, voff_t start, voff_t stop, int flags) 906 { 907 struct uvm_aobj *aobj = (struct uvm_aobj *) uobj; 908 struct vm_page *pp; 909 voff_t curoff; 910 911 if (flags & PGO_ALLPAGES) { 912 start = 0; 913 stop = (voff_t)aobj->u_pages << PAGE_SHIFT; 914 } else { 915 start = trunc_page(start); 916 stop = round_page(stop); 917 if (stop > ((voff_t)aobj->u_pages << PAGE_SHIFT)) { 918 printf("uao_flush: strange, got an out of range " 919 "flush (fixed)\n"); 920 stop = (voff_t)aobj->u_pages << PAGE_SHIFT; 921 } 922 } 923 924 /* 925 * Don't need to do any work here if we're not freeing 926 * or deactivating pages. 927 */ 928 if ((flags & (PGO_DEACTIVATE|PGO_FREE)) == 0) 929 return (TRUE); 930 931 curoff = start; 932 for (;;) { 933 if (curoff < stop) { 934 pp = uvm_pagelookup(uobj, curoff); 935 curoff += PAGE_SIZE; 936 if (pp == NULL) 937 continue; 938 } else { 939 break; 940 } 941 942 /* Make sure page is unbusy, else wait for it. */ 943 if (pp->pg_flags & PG_BUSY) { 944 atomic_setbits_int(&pp->pg_flags, PG_WANTED); 945 tsleep_nsec(pp, PVM, "uaoflsh", INFSLP); 946 curoff -= PAGE_SIZE; 947 continue; 948 } 949 950 switch (flags & (PGO_CLEANIT|PGO_FREE|PGO_DEACTIVATE)) { 951 /* 952 * XXX In these first 3 cases, we always just 953 * XXX deactivate the page. We may want to 954 * XXX handle the different cases more specifically 955 * XXX in the future. 956 */ 957 case PGO_CLEANIT|PGO_FREE: 958 /* FALLTHROUGH */ 959 case PGO_CLEANIT|PGO_DEACTIVATE: 960 /* FALLTHROUGH */ 961 case PGO_DEACTIVATE: 962 deactivate_it: 963 /* skip the page if it's wired */ 964 if (pp->wire_count != 0) 965 continue; 966 967 uvm_lock_pageq(); 968 /* zap all mappings for the page. */ 969 pmap_page_protect(pp, PROT_NONE); 970 971 /* ...and deactivate the page. */ 972 uvm_pagedeactivate(pp); 973 uvm_unlock_pageq(); 974 975 continue; 976 case PGO_FREE: 977 /* 978 * If there are multiple references to 979 * the object, just deactivate the page. 980 */ 981 if (uobj->uo_refs > 1) 982 goto deactivate_it; 983 984 /* XXX skip the page if it's wired */ 985 if (pp->wire_count != 0) 986 continue; 987 988 /* zap all mappings for the page. */ 989 pmap_page_protect(pp, PROT_NONE); 990 991 uao_dropswap(uobj, pp->offset >> PAGE_SHIFT); 992 uvm_lock_pageq(); 993 uvm_pagefree(pp); 994 uvm_unlock_pageq(); 995 996 continue; 997 default: 998 panic("uao_flush: weird flags"); 999 } 1000 } 1001 1002 return (TRUE); 1003 } 1004 1005 /* 1006 * uao_get: fetch me a page 1007 * 1008 * we have three cases: 1009 * 1: page is resident -> just return the page. 1010 * 2: page is zero-fill -> allocate a new page and zero it. 1011 * 3: page is swapped out -> fetch the page from swap. 1012 * 1013 * cases 1 and 2 can be handled with PGO_LOCKED, case 3 cannot. 1014 * so, if the "center" page hits case 3 (or any page, with PGO_ALLPAGES), 1015 * then we will need to return VM_PAGER_UNLOCK. 1016 * 1017 * => flags: PGO_ALLPAGES: get all of the pages 1018 * PGO_LOCKED: fault data structures are locked 1019 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 1020 * => NOTE: caller must check for released pages!! 1021 */ 1022 static int 1023 uao_get(struct uvm_object *uobj, voff_t offset, struct vm_page **pps, 1024 int *npagesp, int centeridx, vm_prot_t access_type, int advice, int flags) 1025 { 1026 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 1027 voff_t current_offset; 1028 vm_page_t ptmp; 1029 int lcv, gotpages, maxpages, swslot, rv, pageidx; 1030 boolean_t done; 1031 1032 /* get number of pages */ 1033 maxpages = *npagesp; 1034 1035 /* step 1: handled the case where fault data structures are locked. */ 1036 if (flags & PGO_LOCKED) { 1037 /* step 1a: get pages that are already resident. */ 1038 1039 done = TRUE; /* be optimistic */ 1040 gotpages = 0; /* # of pages we got so far */ 1041 1042 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 1043 lcv++, current_offset += PAGE_SIZE) { 1044 /* do we care about this page? if not, skip it */ 1045 if (pps[lcv] == PGO_DONTCARE) 1046 continue; 1047 1048 ptmp = uvm_pagelookup(uobj, current_offset); 1049 1050 /* 1051 * if page is new, attempt to allocate the page, 1052 * zero-fill'd. 1053 */ 1054 if (ptmp == NULL && uao_find_swslot(aobj, 1055 current_offset >> PAGE_SHIFT) == 0) { 1056 ptmp = uvm_pagealloc(uobj, current_offset, 1057 NULL, UVM_PGA_ZERO); 1058 if (ptmp) { 1059 /* new page */ 1060 atomic_clearbits_int(&ptmp->pg_flags, 1061 PG_BUSY|PG_FAKE); 1062 atomic_setbits_int(&ptmp->pg_flags, 1063 PQ_AOBJ); 1064 UVM_PAGE_OWN(ptmp, NULL); 1065 } 1066 } 1067 1068 /* to be useful must get a non-busy page */ 1069 if (ptmp == NULL || 1070 (ptmp->pg_flags & PG_BUSY) != 0) { 1071 if (lcv == centeridx || 1072 (flags & PGO_ALLPAGES) != 0) 1073 /* need to do a wait or I/O! */ 1074 done = FALSE; 1075 continue; 1076 } 1077 1078 /* 1079 * useful page: busy it and plug it in our 1080 * result array 1081 */ 1082 /* caller must un-busy this page */ 1083 atomic_setbits_int(&ptmp->pg_flags, PG_BUSY); 1084 UVM_PAGE_OWN(ptmp, "uao_get1"); 1085 pps[lcv] = ptmp; 1086 gotpages++; 1087 1088 } 1089 1090 /* 1091 * step 1b: now we've either done everything needed or we 1092 * to unlock and do some waiting or I/O. 1093 */ 1094 *npagesp = gotpages; 1095 if (done) 1096 /* bingo! */ 1097 return(VM_PAGER_OK); 1098 else 1099 /* EEK! Need to unlock and I/O */ 1100 return(VM_PAGER_UNLOCK); 1101 } 1102 1103 /* 1104 * step 2: get non-resident or busy pages. 1105 * data structures are unlocked. 1106 */ 1107 for (lcv = 0, current_offset = offset ; lcv < maxpages ; 1108 lcv++, current_offset += PAGE_SIZE) { 1109 /* 1110 * - skip over pages we've already gotten or don't want 1111 * - skip over pages we don't _have_ to get 1112 */ 1113 if (pps[lcv] != NULL || 1114 (lcv != centeridx && (flags & PGO_ALLPAGES) == 0)) 1115 continue; 1116 1117 pageidx = current_offset >> PAGE_SHIFT; 1118 1119 /* 1120 * we have yet to locate the current page (pps[lcv]). we 1121 * first look for a page that is already at the current offset. 1122 * if we find a page, we check to see if it is busy or 1123 * released. if that is the case, then we sleep on the page 1124 * until it is no longer busy or released and repeat the lookup. 1125 * if the page we found is neither busy nor released, then we 1126 * busy it (so we own it) and plug it into pps[lcv]. this 1127 * 'break's the following while loop and indicates we are 1128 * ready to move on to the next page in the "lcv" loop above. 1129 * 1130 * if we exit the while loop with pps[lcv] still set to NULL, 1131 * then it means that we allocated a new busy/fake/clean page 1132 * ptmp in the object and we need to do I/O to fill in the data. 1133 */ 1134 1135 /* top of "pps" while loop */ 1136 while (pps[lcv] == NULL) { 1137 /* look for a resident page */ 1138 ptmp = uvm_pagelookup(uobj, current_offset); 1139 1140 /* not resident? allocate one now (if we can) */ 1141 if (ptmp == NULL) { 1142 1143 ptmp = uvm_pagealloc(uobj, current_offset, 1144 NULL, 0); 1145 1146 /* out of RAM? */ 1147 if (ptmp == NULL) { 1148 uvm_wait("uao_getpage"); 1149 /* goto top of pps while loop */ 1150 continue; 1151 } 1152 1153 /* 1154 * safe with PQ's unlocked: because we just 1155 * alloc'd the page 1156 */ 1157 atomic_setbits_int(&ptmp->pg_flags, PQ_AOBJ); 1158 1159 /* 1160 * got new page ready for I/O. break pps while 1161 * loop. pps[lcv] is still NULL. 1162 */ 1163 break; 1164 } 1165 1166 /* page is there, see if we need to wait on it */ 1167 if ((ptmp->pg_flags & PG_BUSY) != 0) { 1168 atomic_setbits_int(&ptmp->pg_flags, PG_WANTED); 1169 tsleep_nsec(ptmp, PVM, "uao_get", INFSLP); 1170 continue; /* goto top of pps while loop */ 1171 } 1172 1173 /* 1174 * if we get here then the page has become resident and 1175 * unbusy between steps 1 and 2. we busy it now (so we 1176 * own it) and set pps[lcv] (so that we exit the while 1177 * loop). 1178 */ 1179 /* we own it, caller must un-busy */ 1180 atomic_setbits_int(&ptmp->pg_flags, PG_BUSY); 1181 UVM_PAGE_OWN(ptmp, "uao_get2"); 1182 pps[lcv] = ptmp; 1183 } 1184 1185 /* 1186 * if we own the valid page at the correct offset, pps[lcv] will 1187 * point to it. nothing more to do except go to the next page. 1188 */ 1189 if (pps[lcv]) 1190 continue; /* next lcv */ 1191 1192 /* 1193 * we have a "fake/busy/clean" page that we just allocated. 1194 * do the needed "i/o", either reading from swap or zeroing. 1195 */ 1196 swslot = uao_find_swslot(aobj, pageidx); 1197 1198 /* just zero the page if there's nothing in swap. */ 1199 if (swslot == 0) { 1200 /* page hasn't existed before, just zero it. */ 1201 uvm_pagezero(ptmp); 1202 } else { 1203 /* page in the swapped-out page. */ 1204 rv = uvm_swap_get(ptmp, swslot, PGO_SYNCIO); 1205 1206 /* I/O done. check for errors. */ 1207 if (rv != VM_PAGER_OK) { 1208 /* 1209 * remove the swap slot from the aobj 1210 * and mark the aobj as having no real slot. 1211 * don't free the swap slot, thus preventing 1212 * it from being used again. 1213 */ 1214 swslot = uao_set_swslot(&aobj->u_obj, pageidx, 1215 SWSLOT_BAD); 1216 uvm_swap_markbad(swslot, 1); 1217 1218 if (ptmp->pg_flags & PG_WANTED) 1219 wakeup(ptmp); 1220 atomic_clearbits_int(&ptmp->pg_flags, 1221 PG_WANTED|PG_BUSY); 1222 UVM_PAGE_OWN(ptmp, NULL); 1223 uvm_lock_pageq(); 1224 uvm_pagefree(ptmp); 1225 uvm_unlock_pageq(); 1226 1227 return (rv); 1228 } 1229 } 1230 1231 /* 1232 * we got the page! clear the fake flag (indicates valid 1233 * data now in page) and plug into our result array. note 1234 * that page is still busy. 1235 * 1236 * it is the callers job to: 1237 * => check if the page is released 1238 * => unbusy the page 1239 * => activate the page 1240 */ 1241 1242 /* data is valid ... */ 1243 atomic_clearbits_int(&ptmp->pg_flags, PG_FAKE); 1244 pmap_clear_modify(ptmp); /* ... and clean */ 1245 pps[lcv] = ptmp; 1246 1247 } /* lcv loop */ 1248 1249 return(VM_PAGER_OK); 1250 } 1251 1252 /* 1253 * uao_dropswap: release any swap resources from this aobj page. 1254 */ 1255 int 1256 uao_dropswap(struct uvm_object *uobj, int pageidx) 1257 { 1258 int slot; 1259 1260 slot = uao_set_swslot(uobj, pageidx, 0); 1261 if (slot) { 1262 uvm_swap_free(slot, 1); 1263 } 1264 return (slot); 1265 } 1266 1267 /* 1268 * page in every page in every aobj that is paged-out to a range of swslots. 1269 * 1270 * => returns TRUE if pagein was aborted due to lack of memory. 1271 */ 1272 boolean_t 1273 uao_swap_off(int startslot, int endslot) 1274 { 1275 struct uvm_aobj *aobj, *nextaobj, *prevaobj = NULL; 1276 1277 /* walk the list of all aobjs. */ 1278 mtx_enter(&uao_list_lock); 1279 1280 for (aobj = LIST_FIRST(&uao_list); 1281 aobj != NULL; 1282 aobj = nextaobj) { 1283 boolean_t rv; 1284 1285 /* 1286 * add a ref to the aobj so it doesn't disappear 1287 * while we're working. 1288 */ 1289 uao_reference_locked(&aobj->u_obj); 1290 1291 /* 1292 * now it's safe to unlock the uao list. 1293 * note that lock interleaving is alright with IPL_NONE mutexes. 1294 */ 1295 mtx_leave(&uao_list_lock); 1296 1297 if (prevaobj) { 1298 uao_detach_locked(&prevaobj->u_obj); 1299 prevaobj = NULL; 1300 } 1301 1302 /* 1303 * page in any pages in the swslot range. 1304 * if there's an error, abort and return the error. 1305 */ 1306 rv = uao_pagein(aobj, startslot, endslot); 1307 if (rv) { 1308 uao_detach_locked(&aobj->u_obj); 1309 return rv; 1310 } 1311 1312 /* 1313 * we're done with this aobj. 1314 * relock the list and drop our ref on the aobj. 1315 */ 1316 mtx_enter(&uao_list_lock); 1317 nextaobj = LIST_NEXT(aobj, u_list); 1318 /* 1319 * prevaobj means that we have an object that we need 1320 * to drop a reference for. We can't just drop it now with 1321 * the list locked since that could cause lock recursion in 1322 * the case where we reduce the refcount to 0. It will be 1323 * released the next time we drop the list lock. 1324 */ 1325 prevaobj = aobj; 1326 } 1327 1328 /* done with traversal, unlock the list */ 1329 mtx_leave(&uao_list_lock); 1330 if (prevaobj) { 1331 uao_detach_locked(&prevaobj->u_obj); 1332 } 1333 return FALSE; 1334 } 1335 1336 /* 1337 * page in any pages from aobj in the given range. 1338 * 1339 * => returns TRUE if pagein was aborted due to lack of memory. 1340 */ 1341 static boolean_t 1342 uao_pagein(struct uvm_aobj *aobj, int startslot, int endslot) 1343 { 1344 boolean_t rv; 1345 1346 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 1347 struct uao_swhash_elt *elt; 1348 int bucket; 1349 1350 restart: 1351 for (bucket = aobj->u_swhashmask; bucket >= 0; bucket--) { 1352 for (elt = LIST_FIRST(&aobj->u_swhash[bucket]); 1353 elt != NULL; 1354 elt = LIST_NEXT(elt, list)) { 1355 int i; 1356 1357 for (i = 0; i < UAO_SWHASH_CLUSTER_SIZE; i++) { 1358 int slot = elt->slots[i]; 1359 1360 /* if slot isn't in range, skip it. */ 1361 if (slot < startslot || 1362 slot >= endslot) { 1363 continue; 1364 } 1365 1366 /* 1367 * process the page, 1368 * the start over on this object 1369 * since the swhash elt 1370 * may have been freed. 1371 */ 1372 rv = uao_pagein_page(aobj, 1373 UAO_SWHASH_ELT_PAGEIDX_BASE(elt) + i); 1374 if (rv) { 1375 return rv; 1376 } 1377 goto restart; 1378 } 1379 } 1380 } 1381 } else { 1382 int i; 1383 1384 for (i = 0; i < aobj->u_pages; i++) { 1385 int slot = aobj->u_swslots[i]; 1386 1387 /* if the slot isn't in range, skip it */ 1388 if (slot < startslot || slot >= endslot) { 1389 continue; 1390 } 1391 1392 /* process the page. */ 1393 rv = uao_pagein_page(aobj, i); 1394 if (rv) { 1395 return rv; 1396 } 1397 } 1398 } 1399 1400 return FALSE; 1401 } 1402 1403 /* 1404 * page in a page from an aobj. used for swap_off. 1405 * returns TRUE if pagein was aborted due to lack of memory. 1406 */ 1407 static boolean_t 1408 uao_pagein_page(struct uvm_aobj *aobj, int pageidx) 1409 { 1410 struct vm_page *pg; 1411 int rv, slot, npages; 1412 1413 pg = NULL; 1414 npages = 1; 1415 rv = uao_get(&aobj->u_obj, (voff_t)pageidx << PAGE_SHIFT, 1416 &pg, &npages, 0, PROT_READ | PROT_WRITE, 0, 0); 1417 1418 switch (rv) { 1419 case VM_PAGER_OK: 1420 break; 1421 1422 case VM_PAGER_ERROR: 1423 case VM_PAGER_REFAULT: 1424 /* 1425 * nothing more to do on errors. 1426 * VM_PAGER_REFAULT can only mean that the anon was freed, 1427 * so again there's nothing to do. 1428 */ 1429 return FALSE; 1430 } 1431 1432 /* 1433 * ok, we've got the page now. 1434 * mark it as dirty, clear its swslot and un-busy it. 1435 */ 1436 slot = uao_set_swslot(&aobj->u_obj, pageidx, 0); 1437 uvm_swap_free(slot, 1); 1438 atomic_clearbits_int(&pg->pg_flags, PG_BUSY|PG_CLEAN|PG_FAKE); 1439 UVM_PAGE_OWN(pg, NULL); 1440 1441 /* deactivate the page (to put it on a page queue). */ 1442 pmap_clear_reference(pg); 1443 uvm_lock_pageq(); 1444 uvm_pagedeactivate(pg); 1445 uvm_unlock_pageq(); 1446 1447 return FALSE; 1448 } 1449 1450 /* 1451 * XXX pedro: Once we are comfortable enough with this function, we can adapt 1452 * uao_free() to use it. 1453 * 1454 * uao_dropswap_range: drop swapslots in the range. 1455 * 1456 * => aobj must be locked and is returned locked. 1457 * => start is inclusive. end is exclusive. 1458 */ 1459 void 1460 uao_dropswap_range(struct uvm_object *uobj, voff_t start, voff_t end) 1461 { 1462 struct uvm_aobj *aobj = (struct uvm_aobj *)uobj; 1463 int swpgonlydelta = 0; 1464 1465 /* KASSERT(mutex_owned(uobj->vmobjlock)); */ 1466 1467 if (end == 0) { 1468 end = INT64_MAX; 1469 } 1470 1471 if (aobj->u_pages > UAO_SWHASH_THRESHOLD) { 1472 int i, hashbuckets = aobj->u_swhashmask + 1; 1473 voff_t taghi; 1474 voff_t taglo; 1475 1476 taglo = UAO_SWHASH_ELT_TAG(start); 1477 taghi = UAO_SWHASH_ELT_TAG(end); 1478 1479 for (i = 0; i < hashbuckets; i++) { 1480 struct uao_swhash_elt *elt, *next; 1481 1482 for (elt = LIST_FIRST(&aobj->u_swhash[i]); 1483 elt != NULL; 1484 elt = next) { 1485 int startidx, endidx; 1486 int j; 1487 1488 next = LIST_NEXT(elt, list); 1489 1490 if (elt->tag < taglo || taghi < elt->tag) { 1491 continue; 1492 } 1493 1494 if (elt->tag == taglo) { 1495 startidx = 1496 UAO_SWHASH_ELT_PAGESLOT_IDX(start); 1497 } else { 1498 startidx = 0; 1499 } 1500 1501 if (elt->tag == taghi) { 1502 endidx = 1503 UAO_SWHASH_ELT_PAGESLOT_IDX(end); 1504 } else { 1505 endidx = UAO_SWHASH_CLUSTER_SIZE; 1506 } 1507 1508 for (j = startidx; j < endidx; j++) { 1509 int slot = elt->slots[j]; 1510 1511 KASSERT(uvm_pagelookup(&aobj->u_obj, 1512 (voff_t)(UAO_SWHASH_ELT_PAGEIDX_BASE(elt) 1513 + j) << PAGE_SHIFT) == NULL); 1514 1515 if (slot > 0) { 1516 uvm_swap_free(slot, 1); 1517 swpgonlydelta++; 1518 KASSERT(elt->count > 0); 1519 elt->slots[j] = 0; 1520 elt->count--; 1521 } 1522 } 1523 1524 if (elt->count == 0) { 1525 LIST_REMOVE(elt, list); 1526 pool_put(&uao_swhash_elt_pool, elt); 1527 } 1528 } 1529 } 1530 } else { 1531 int i; 1532 1533 if (aobj->u_pages < end) { 1534 end = aobj->u_pages; 1535 } 1536 for (i = start; i < end; i++) { 1537 int slot = aobj->u_swslots[i]; 1538 1539 if (slot > 0) { 1540 uvm_swap_free(slot, 1); 1541 swpgonlydelta++; 1542 } 1543 } 1544 } 1545 1546 /* 1547 * adjust the counter of pages only in swap for all 1548 * the swap slots we've freed. 1549 */ 1550 if (swpgonlydelta > 0) { 1551 KASSERT(uvmexp.swpgonly >= swpgonlydelta); 1552 uvmexp.swpgonly -= swpgonlydelta; 1553 } 1554 } 1555