1 /*- 2 * Copyright (c) 2002-2006 Rice University 3 * Copyright (c) 2007-2011 Alan L. Cox <alc@cs.rice.edu> 4 * All rights reserved. 5 * 6 * This software was developed for the FreeBSD Project by Alan L. Cox, 7 * Olivier Crameri, Peter Druschel, Sitaram Iyer, and Juan Navarro. 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 COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 24 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 25 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 26 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY 28 * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * Superpage reservation management module 34 * 35 * Any external functions defined by this module are only to be used by the 36 * virtual memory system. 37 */ 38 39 #include <sys/cdefs.h> 40 __FBSDID("$FreeBSD$"); 41 42 #include "opt_vm.h" 43 44 #include <sys/param.h> 45 #include <sys/kernel.h> 46 #include <sys/lock.h> 47 #include <sys/malloc.h> 48 #include <sys/mutex.h> 49 #include <sys/queue.h> 50 #include <sys/rwlock.h> 51 #include <sys/sbuf.h> 52 #include <sys/sysctl.h> 53 #include <sys/systm.h> 54 55 #include <vm/vm.h> 56 #include <vm/vm_param.h> 57 #include <vm/vm_object.h> 58 #include <vm/vm_page.h> 59 #include <vm/vm_phys.h> 60 #include <vm/vm_radix.h> 61 #include <vm/vm_reserv.h> 62 63 /* 64 * The reservation system supports the speculative allocation of large physical 65 * pages ("superpages"). Speculative allocation enables the fully-automatic 66 * utilization of superpages by the virtual memory system. In other words, no 67 * programmatic directives are required to use superpages. 68 */ 69 70 #if VM_NRESERVLEVEL > 0 71 72 /* 73 * The number of small pages that are contained in a level 0 reservation 74 */ 75 #define VM_LEVEL_0_NPAGES (1 << VM_LEVEL_0_ORDER) 76 77 /* 78 * The number of bits by which a physical address is shifted to obtain the 79 * reservation number 80 */ 81 #define VM_LEVEL_0_SHIFT (VM_LEVEL_0_ORDER + PAGE_SHIFT) 82 83 /* 84 * The size of a level 0 reservation in bytes 85 */ 86 #define VM_LEVEL_0_SIZE (1 << VM_LEVEL_0_SHIFT) 87 88 /* 89 * Computes the index of the small page underlying the given (object, pindex) 90 * within the reservation's array of small pages. 91 */ 92 #define VM_RESERV_INDEX(object, pindex) \ 93 (((object)->pg_color + (pindex)) & (VM_LEVEL_0_NPAGES - 1)) 94 95 /* 96 * The size of a population map entry 97 */ 98 typedef u_long popmap_t; 99 100 /* 101 * The number of bits in a population map entry 102 */ 103 #define NBPOPMAP (NBBY * sizeof(popmap_t)) 104 105 /* 106 * The number of population map entries in a reservation 107 */ 108 #define NPOPMAP howmany(VM_LEVEL_0_NPAGES, NBPOPMAP) 109 110 /* 111 * Clear a bit in the population map. 112 */ 113 static __inline void 114 popmap_clear(popmap_t popmap[], int i) 115 { 116 117 popmap[i / NBPOPMAP] &= ~(1UL << (i % NBPOPMAP)); 118 } 119 120 /* 121 * Set a bit in the population map. 122 */ 123 static __inline void 124 popmap_set(popmap_t popmap[], int i) 125 { 126 127 popmap[i / NBPOPMAP] |= 1UL << (i % NBPOPMAP); 128 } 129 130 /* 131 * Is a bit in the population map clear? 132 */ 133 static __inline boolean_t 134 popmap_is_clear(popmap_t popmap[], int i) 135 { 136 137 return ((popmap[i / NBPOPMAP] & (1UL << (i % NBPOPMAP))) == 0); 138 } 139 140 /* 141 * Is a bit in the population map set? 142 */ 143 static __inline boolean_t 144 popmap_is_set(popmap_t popmap[], int i) 145 { 146 147 return ((popmap[i / NBPOPMAP] & (1UL << (i % NBPOPMAP))) != 0); 148 } 149 150 /* 151 * The reservation structure 152 * 153 * A reservation structure is constructed whenever a large physical page is 154 * speculatively allocated to an object. The reservation provides the small 155 * physical pages for the range [pindex, pindex + VM_LEVEL_0_NPAGES) of offsets 156 * within that object. The reservation's "popcnt" tracks the number of these 157 * small physical pages that are in use at any given time. When and if the 158 * reservation is not fully utilized, it appears in the queue of partially- 159 * populated reservations. The reservation always appears on the containing 160 * object's list of reservations. 161 * 162 * A partially-populated reservation can be broken and reclaimed at any time. 163 */ 164 struct vm_reserv { 165 TAILQ_ENTRY(vm_reserv) partpopq; 166 LIST_ENTRY(vm_reserv) objq; 167 vm_object_t object; /* containing object */ 168 vm_pindex_t pindex; /* offset within object */ 169 vm_page_t pages; /* first page of a superpage */ 170 int popcnt; /* # of pages in use */ 171 char inpartpopq; 172 popmap_t popmap[NPOPMAP]; /* bit vector of used pages */ 173 }; 174 175 /* 176 * The reservation array 177 * 178 * This array is analoguous in function to vm_page_array. It differs in the 179 * respect that it may contain a greater number of useful reservation 180 * structures than there are (physical) superpages. These "invalid" 181 * reservation structures exist to trade-off space for time in the 182 * implementation of vm_reserv_from_page(). Invalid reservation structures are 183 * distinguishable from "valid" reservation structures by inspecting the 184 * reservation's "pages" field. Invalid reservation structures have a NULL 185 * "pages" field. 186 * 187 * vm_reserv_from_page() maps a small (physical) page to an element of this 188 * array by computing a physical reservation number from the page's physical 189 * address. The physical reservation number is used as the array index. 190 * 191 * An "active" reservation is a valid reservation structure that has a non-NULL 192 * "object" field and a non-zero "popcnt" field. In other words, every active 193 * reservation belongs to a particular object. Moreover, every active 194 * reservation has an entry in the containing object's list of reservations. 195 */ 196 static vm_reserv_t vm_reserv_array; 197 198 /* 199 * The partially-populated reservation queue 200 * 201 * This queue enables the fast recovery of an unused cached or free small page 202 * from a partially-populated reservation. The reservation at the head of 203 * this queue is the least-recently-changed, partially-populated reservation. 204 * 205 * Access to this queue is synchronized by the free page queue lock. 206 */ 207 static TAILQ_HEAD(, vm_reserv) vm_rvq_partpop = 208 TAILQ_HEAD_INITIALIZER(vm_rvq_partpop); 209 210 static SYSCTL_NODE(_vm, OID_AUTO, reserv, CTLFLAG_RD, 0, "Reservation Info"); 211 212 static long vm_reserv_broken; 213 SYSCTL_LONG(_vm_reserv, OID_AUTO, broken, CTLFLAG_RD, 214 &vm_reserv_broken, 0, "Cumulative number of broken reservations"); 215 216 static long vm_reserv_freed; 217 SYSCTL_LONG(_vm_reserv, OID_AUTO, freed, CTLFLAG_RD, 218 &vm_reserv_freed, 0, "Cumulative number of freed reservations"); 219 220 static int sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS); 221 222 SYSCTL_OID(_vm_reserv, OID_AUTO, partpopq, CTLTYPE_STRING | CTLFLAG_RD, NULL, 0, 223 sysctl_vm_reserv_partpopq, "A", "Partially-populated reservation queues"); 224 225 static long vm_reserv_reclaimed; 226 SYSCTL_LONG(_vm_reserv, OID_AUTO, reclaimed, CTLFLAG_RD, 227 &vm_reserv_reclaimed, 0, "Cumulative number of reclaimed reservations"); 228 229 static void vm_reserv_break(vm_reserv_t rv, vm_page_t m); 230 static void vm_reserv_depopulate(vm_reserv_t rv, int index); 231 static vm_reserv_t vm_reserv_from_page(vm_page_t m); 232 static boolean_t vm_reserv_has_pindex(vm_reserv_t rv, 233 vm_pindex_t pindex); 234 static void vm_reserv_populate(vm_reserv_t rv, int index); 235 static void vm_reserv_reclaim(vm_reserv_t rv); 236 237 /* 238 * Describes the current state of the partially-populated reservation queue. 239 */ 240 static int 241 sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS) 242 { 243 struct sbuf sbuf; 244 vm_reserv_t rv; 245 int counter, error, level, unused_pages; 246 247 error = sysctl_wire_old_buffer(req, 0); 248 if (error != 0) 249 return (error); 250 sbuf_new_for_sysctl(&sbuf, NULL, 128, req); 251 sbuf_printf(&sbuf, "\nLEVEL SIZE NUMBER\n\n"); 252 for (level = -1; level <= VM_NRESERVLEVEL - 2; level++) { 253 counter = 0; 254 unused_pages = 0; 255 mtx_lock(&vm_page_queue_free_mtx); 256 TAILQ_FOREACH(rv, &vm_rvq_partpop/*[level]*/, partpopq) { 257 counter++; 258 unused_pages += VM_LEVEL_0_NPAGES - rv->popcnt; 259 } 260 mtx_unlock(&vm_page_queue_free_mtx); 261 sbuf_printf(&sbuf, "%5d: %6dK, %6d\n", level, 262 unused_pages * ((int)PAGE_SIZE / 1024), counter); 263 } 264 error = sbuf_finish(&sbuf); 265 sbuf_delete(&sbuf); 266 return (error); 267 } 268 269 /* 270 * Reduces the given reservation's population count. If the population count 271 * becomes zero, the reservation is destroyed. Additionally, moves the 272 * reservation to the tail of the partially-populated reservation queue if the 273 * population count is non-zero. 274 * 275 * The free page queue lock must be held. 276 */ 277 static void 278 vm_reserv_depopulate(vm_reserv_t rv, int index) 279 { 280 281 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 282 KASSERT(rv->object != NULL, 283 ("vm_reserv_depopulate: reserv %p is free", rv)); 284 KASSERT(popmap_is_set(rv->popmap, index), 285 ("vm_reserv_depopulate: reserv %p's popmap[%d] is clear", rv, 286 index)); 287 KASSERT(rv->popcnt > 0, 288 ("vm_reserv_depopulate: reserv %p's popcnt is corrupted", rv)); 289 if (rv->inpartpopq) { 290 TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); 291 rv->inpartpopq = FALSE; 292 } else { 293 KASSERT(rv->pages->psind == 1, 294 ("vm_reserv_depopulate: reserv %p is already demoted", 295 rv)); 296 rv->pages->psind = 0; 297 } 298 popmap_clear(rv->popmap, index); 299 rv->popcnt--; 300 if (rv->popcnt == 0) { 301 LIST_REMOVE(rv, objq); 302 rv->object = NULL; 303 vm_phys_free_pages(rv->pages, VM_LEVEL_0_ORDER); 304 vm_reserv_freed++; 305 } else { 306 rv->inpartpopq = TRUE; 307 TAILQ_INSERT_TAIL(&vm_rvq_partpop, rv, partpopq); 308 } 309 } 310 311 /* 312 * Returns the reservation to which the given page might belong. 313 */ 314 static __inline vm_reserv_t 315 vm_reserv_from_page(vm_page_t m) 316 { 317 318 return (&vm_reserv_array[VM_PAGE_TO_PHYS(m) >> VM_LEVEL_0_SHIFT]); 319 } 320 321 /* 322 * Returns TRUE if the given reservation contains the given page index and 323 * FALSE otherwise. 324 */ 325 static __inline boolean_t 326 vm_reserv_has_pindex(vm_reserv_t rv, vm_pindex_t pindex) 327 { 328 329 return (((pindex - rv->pindex) & ~(VM_LEVEL_0_NPAGES - 1)) == 0); 330 } 331 332 /* 333 * Increases the given reservation's population count. Moves the reservation 334 * to the tail of the partially-populated reservation queue. 335 * 336 * The free page queue must be locked. 337 */ 338 static void 339 vm_reserv_populate(vm_reserv_t rv, int index) 340 { 341 342 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 343 KASSERT(rv->object != NULL, 344 ("vm_reserv_populate: reserv %p is free", rv)); 345 KASSERT(popmap_is_clear(rv->popmap, index), 346 ("vm_reserv_populate: reserv %p's popmap[%d] is set", rv, 347 index)); 348 KASSERT(rv->popcnt < VM_LEVEL_0_NPAGES, 349 ("vm_reserv_populate: reserv %p is already full", rv)); 350 KASSERT(rv->pages->psind == 0, 351 ("vm_reserv_populate: reserv %p is already promoted", rv)); 352 if (rv->inpartpopq) { 353 TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); 354 rv->inpartpopq = FALSE; 355 } 356 popmap_set(rv->popmap, index); 357 rv->popcnt++; 358 if (rv->popcnt < VM_LEVEL_0_NPAGES) { 359 rv->inpartpopq = TRUE; 360 TAILQ_INSERT_TAIL(&vm_rvq_partpop, rv, partpopq); 361 } else 362 rv->pages->psind = 1; 363 } 364 365 /* 366 * Allocates a contiguous set of physical pages of the given size "npages" 367 * from an existing or newly-created reservation. All of the physical pages 368 * must be at or above the given physical address "low" and below the given 369 * physical address "high". The given value "alignment" determines the 370 * alignment of the first physical page in the set. If the given value 371 * "boundary" is non-zero, then the set of physical pages cannot cross any 372 * physical address boundary that is a multiple of that value. Both 373 * "alignment" and "boundary" must be a power of two. 374 * 375 * The object and free page queue must be locked. 376 */ 377 vm_page_t 378 vm_reserv_alloc_contig(vm_object_t object, vm_pindex_t pindex, u_long npages, 379 vm_paddr_t low, vm_paddr_t high, u_long alignment, vm_paddr_t boundary) 380 { 381 vm_paddr_t pa, size; 382 vm_page_t m, m_ret, mpred, msucc; 383 vm_pindex_t first, leftcap, rightcap; 384 vm_reserv_t rv; 385 u_long allocpages, maxpages, minpages; 386 int i, index, n; 387 388 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 389 VM_OBJECT_ASSERT_WLOCKED(object); 390 KASSERT(npages != 0, ("vm_reserv_alloc_contig: npages is 0")); 391 392 /* 393 * Is a reservation fundamentally impossible? 394 */ 395 if (pindex < VM_RESERV_INDEX(object, pindex) || 396 pindex + npages > object->size) 397 return (NULL); 398 399 /* 400 * All reservations of a particular size have the same alignment. 401 * Assuming that the first page is allocated from a reservation, the 402 * least significant bits of its physical address can be determined 403 * from its offset from the beginning of the reservation and the size 404 * of the reservation. 405 * 406 * Could the specified index within a reservation of the smallest 407 * possible size satisfy the alignment and boundary requirements? 408 */ 409 pa = VM_RESERV_INDEX(object, pindex) << PAGE_SHIFT; 410 if ((pa & (alignment - 1)) != 0) 411 return (NULL); 412 size = npages << PAGE_SHIFT; 413 if (((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0) 414 return (NULL); 415 416 /* 417 * Look for an existing reservation. 418 */ 419 mpred = vm_radix_lookup_le(&object->rtree, pindex); 420 if (mpred != NULL) { 421 KASSERT(mpred->pindex < pindex, 422 ("vm_reserv_alloc_contig: pindex already allocated")); 423 rv = vm_reserv_from_page(mpred); 424 if (rv->object == object && vm_reserv_has_pindex(rv, pindex)) 425 goto found; 426 msucc = TAILQ_NEXT(mpred, listq); 427 } else 428 msucc = TAILQ_FIRST(&object->memq); 429 if (msucc != NULL) { 430 KASSERT(msucc->pindex > pindex, 431 ("vm_reserv_alloc_page: pindex already allocated")); 432 rv = vm_reserv_from_page(msucc); 433 if (rv->object == object && vm_reserv_has_pindex(rv, pindex)) 434 goto found; 435 } 436 437 /* 438 * Could at least one reservation fit between the first index to the 439 * left that can be used and the first index to the right that cannot 440 * be used? 441 */ 442 first = pindex - VM_RESERV_INDEX(object, pindex); 443 if (mpred != NULL) { 444 if ((rv = vm_reserv_from_page(mpred))->object != object) 445 leftcap = mpred->pindex + 1; 446 else 447 leftcap = rv->pindex + VM_LEVEL_0_NPAGES; 448 if (leftcap > first) 449 return (NULL); 450 } 451 minpages = VM_RESERV_INDEX(object, pindex) + npages; 452 maxpages = roundup2(minpages, VM_LEVEL_0_NPAGES); 453 allocpages = maxpages; 454 if (msucc != NULL) { 455 if ((rv = vm_reserv_from_page(msucc))->object != object) 456 rightcap = msucc->pindex; 457 else 458 rightcap = rv->pindex; 459 if (first + maxpages > rightcap) { 460 if (maxpages == VM_LEVEL_0_NPAGES) 461 return (NULL); 462 allocpages = minpages; 463 } 464 } 465 466 /* 467 * Would the last new reservation extend past the end of the object? 468 */ 469 if (first + maxpages > object->size) { 470 /* 471 * Don't allocate the last new reservation if the object is a 472 * vnode or backed by another object that is a vnode. 473 */ 474 if (object->type == OBJT_VNODE || 475 (object->backing_object != NULL && 476 object->backing_object->type == OBJT_VNODE)) { 477 if (maxpages == VM_LEVEL_0_NPAGES) 478 return (NULL); 479 allocpages = minpages; 480 } 481 /* Speculate that the object may grow. */ 482 } 483 484 /* 485 * Allocate and populate the new reservations. The alignment and 486 * boundary specified for this allocation may be different from the 487 * alignment and boundary specified for the requested pages. For 488 * instance, the specified index may not be the first page within the 489 * first new reservation. 490 */ 491 m = vm_phys_alloc_contig(allocpages, low, high, ulmax(alignment, 492 VM_LEVEL_0_SIZE), boundary > VM_LEVEL_0_SIZE ? boundary : 0); 493 if (m == NULL) 494 return (NULL); 495 m_ret = NULL; 496 index = VM_RESERV_INDEX(object, pindex); 497 do { 498 rv = vm_reserv_from_page(m); 499 KASSERT(rv->pages == m, 500 ("vm_reserv_alloc_contig: reserv %p's pages is corrupted", 501 rv)); 502 KASSERT(rv->object == NULL, 503 ("vm_reserv_alloc_contig: reserv %p isn't free", rv)); 504 LIST_INSERT_HEAD(&object->rvq, rv, objq); 505 rv->object = object; 506 rv->pindex = first; 507 KASSERT(rv->popcnt == 0, 508 ("vm_reserv_alloc_contig: reserv %p's popcnt is corrupted", 509 rv)); 510 KASSERT(!rv->inpartpopq, 511 ("vm_reserv_alloc_contig: reserv %p's inpartpopq is TRUE", 512 rv)); 513 for (i = 0; i < NPOPMAP; i++) 514 KASSERT(rv->popmap[i] == 0, 515 ("vm_reserv_alloc_contig: reserv %p's popmap is corrupted", 516 rv)); 517 n = ulmin(VM_LEVEL_0_NPAGES - index, npages); 518 for (i = 0; i < n; i++) 519 vm_reserv_populate(rv, index + i); 520 npages -= n; 521 if (m_ret == NULL) { 522 m_ret = &rv->pages[index]; 523 index = 0; 524 } 525 m += VM_LEVEL_0_NPAGES; 526 first += VM_LEVEL_0_NPAGES; 527 allocpages -= VM_LEVEL_0_NPAGES; 528 } while (allocpages > 0); 529 return (m_ret); 530 531 /* 532 * Found a matching reservation. 533 */ 534 found: 535 index = VM_RESERV_INDEX(object, pindex); 536 /* Does the allocation fit within the reservation? */ 537 if (index + npages > VM_LEVEL_0_NPAGES) 538 return (NULL); 539 m = &rv->pages[index]; 540 pa = VM_PAGE_TO_PHYS(m); 541 if (pa < low || pa + size > high || (pa & (alignment - 1)) != 0 || 542 ((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0) 543 return (NULL); 544 /* Handle vm_page_rename(m, new_object, ...). */ 545 for (i = 0; i < npages; i++) 546 if (popmap_is_set(rv->popmap, index + i)) 547 return (NULL); 548 for (i = 0; i < npages; i++) 549 vm_reserv_populate(rv, index + i); 550 return (m); 551 } 552 553 /* 554 * Allocates a page from an existing or newly-created reservation. 555 * 556 * The page "mpred" must immediately precede the offset "pindex" within the 557 * specified object. 558 * 559 * The object and free page queue must be locked. 560 */ 561 vm_page_t 562 vm_reserv_alloc_page(vm_object_t object, vm_pindex_t pindex, vm_page_t mpred) 563 { 564 vm_page_t m, msucc; 565 vm_pindex_t first, leftcap, rightcap; 566 vm_reserv_t rv; 567 int i, index; 568 569 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 570 VM_OBJECT_ASSERT_WLOCKED(object); 571 572 /* 573 * Is a reservation fundamentally impossible? 574 */ 575 if (pindex < VM_RESERV_INDEX(object, pindex) || 576 pindex >= object->size) 577 return (NULL); 578 579 /* 580 * Look for an existing reservation. 581 */ 582 if (mpred != NULL) { 583 KASSERT(mpred->object == object, 584 ("vm_reserv_alloc_page: object doesn't contain mpred")); 585 KASSERT(mpred->pindex < pindex, 586 ("vm_reserv_alloc_page: mpred doesn't precede pindex")); 587 rv = vm_reserv_from_page(mpred); 588 if (rv->object == object && vm_reserv_has_pindex(rv, pindex)) 589 goto found; 590 msucc = TAILQ_NEXT(mpred, listq); 591 } else 592 msucc = TAILQ_FIRST(&object->memq); 593 if (msucc != NULL) { 594 KASSERT(msucc->pindex > pindex, 595 ("vm_reserv_alloc_page: msucc doesn't succeed pindex")); 596 rv = vm_reserv_from_page(msucc); 597 if (rv->object == object && vm_reserv_has_pindex(rv, pindex)) 598 goto found; 599 } 600 601 /* 602 * Could a reservation fit between the first index to the left that 603 * can be used and the first index to the right that cannot be used? 604 */ 605 first = pindex - VM_RESERV_INDEX(object, pindex); 606 if (mpred != NULL) { 607 if ((rv = vm_reserv_from_page(mpred))->object != object) 608 leftcap = mpred->pindex + 1; 609 else 610 leftcap = rv->pindex + VM_LEVEL_0_NPAGES; 611 if (leftcap > first) 612 return (NULL); 613 } 614 if (msucc != NULL) { 615 if ((rv = vm_reserv_from_page(msucc))->object != object) 616 rightcap = msucc->pindex; 617 else 618 rightcap = rv->pindex; 619 if (first + VM_LEVEL_0_NPAGES > rightcap) 620 return (NULL); 621 } 622 623 /* 624 * Would a new reservation extend past the end of the object? 625 */ 626 if (first + VM_LEVEL_0_NPAGES > object->size) { 627 /* 628 * Don't allocate a new reservation if the object is a vnode or 629 * backed by another object that is a vnode. 630 */ 631 if (object->type == OBJT_VNODE || 632 (object->backing_object != NULL && 633 object->backing_object->type == OBJT_VNODE)) 634 return (NULL); 635 /* Speculate that the object may grow. */ 636 } 637 638 /* 639 * Allocate and populate the new reservation. 640 */ 641 m = vm_phys_alloc_pages(VM_FREEPOOL_DEFAULT, VM_LEVEL_0_ORDER); 642 if (m == NULL) 643 return (NULL); 644 rv = vm_reserv_from_page(m); 645 KASSERT(rv->pages == m, 646 ("vm_reserv_alloc_page: reserv %p's pages is corrupted", rv)); 647 KASSERT(rv->object == NULL, 648 ("vm_reserv_alloc_page: reserv %p isn't free", rv)); 649 LIST_INSERT_HEAD(&object->rvq, rv, objq); 650 rv->object = object; 651 rv->pindex = first; 652 KASSERT(rv->popcnt == 0, 653 ("vm_reserv_alloc_page: reserv %p's popcnt is corrupted", rv)); 654 KASSERT(!rv->inpartpopq, 655 ("vm_reserv_alloc_page: reserv %p's inpartpopq is TRUE", rv)); 656 for (i = 0; i < NPOPMAP; i++) 657 KASSERT(rv->popmap[i] == 0, 658 ("vm_reserv_alloc_page: reserv %p's popmap is corrupted", 659 rv)); 660 index = VM_RESERV_INDEX(object, pindex); 661 vm_reserv_populate(rv, index); 662 return (&rv->pages[index]); 663 664 /* 665 * Found a matching reservation. 666 */ 667 found: 668 index = VM_RESERV_INDEX(object, pindex); 669 m = &rv->pages[index]; 670 /* Handle vm_page_rename(m, new_object, ...). */ 671 if (popmap_is_set(rv->popmap, index)) 672 return (NULL); 673 vm_reserv_populate(rv, index); 674 return (m); 675 } 676 677 /* 678 * Breaks the given reservation. Except for the specified cached or free 679 * page, all cached and free pages in the reservation are returned to the 680 * physical memory allocator. The reservation's population count and map are 681 * reset to their initial state. 682 * 683 * The given reservation must not be in the partially-populated reservation 684 * queue. The free page queue lock must be held. 685 */ 686 static void 687 vm_reserv_break(vm_reserv_t rv, vm_page_t m) 688 { 689 int begin_zeroes, hi, i, lo; 690 691 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 692 KASSERT(rv->object != NULL, 693 ("vm_reserv_break: reserv %p is free", rv)); 694 KASSERT(!rv->inpartpopq, 695 ("vm_reserv_break: reserv %p's inpartpopq is TRUE", rv)); 696 LIST_REMOVE(rv, objq); 697 rv->object = NULL; 698 if (m != NULL) { 699 /* 700 * Since the reservation is being broken, there is no harm in 701 * abusing the population map to stop "m" from being returned 702 * to the physical memory allocator. 703 */ 704 i = m - rv->pages; 705 KASSERT(popmap_is_clear(rv->popmap, i), 706 ("vm_reserv_break: reserv %p's popmap is corrupted", rv)); 707 popmap_set(rv->popmap, i); 708 rv->popcnt++; 709 } 710 i = hi = 0; 711 do { 712 /* Find the next 0 bit. Any previous 0 bits are < "hi". */ 713 lo = ffsl(~(((1UL << hi) - 1) | rv->popmap[i])); 714 if (lo == 0) { 715 /* Redundantly clears bits < "hi". */ 716 rv->popmap[i] = 0; 717 rv->popcnt -= NBPOPMAP - hi; 718 while (++i < NPOPMAP) { 719 lo = ffsl(~rv->popmap[i]); 720 if (lo == 0) { 721 rv->popmap[i] = 0; 722 rv->popcnt -= NBPOPMAP; 723 } else 724 break; 725 } 726 if (i == NPOPMAP) 727 break; 728 hi = 0; 729 } 730 KASSERT(lo > 0, ("vm_reserv_break: lo is %d", lo)); 731 /* Convert from ffsl() to ordinary bit numbering. */ 732 lo--; 733 if (lo > 0) { 734 /* Redundantly clears bits < "hi". */ 735 rv->popmap[i] &= ~((1UL << lo) - 1); 736 rv->popcnt -= lo - hi; 737 } 738 begin_zeroes = NBPOPMAP * i + lo; 739 /* Find the next 1 bit. */ 740 do 741 hi = ffsl(rv->popmap[i]); 742 while (hi == 0 && ++i < NPOPMAP); 743 if (i != NPOPMAP) 744 /* Convert from ffsl() to ordinary bit numbering. */ 745 hi--; 746 vm_phys_free_contig(&rv->pages[begin_zeroes], NBPOPMAP * i + 747 hi - begin_zeroes); 748 } while (i < NPOPMAP); 749 KASSERT(rv->popcnt == 0, 750 ("vm_reserv_break: reserv %p's popcnt is corrupted", rv)); 751 vm_reserv_broken++; 752 } 753 754 /* 755 * Breaks all reservations belonging to the given object. 756 */ 757 void 758 vm_reserv_break_all(vm_object_t object) 759 { 760 vm_reserv_t rv; 761 762 mtx_lock(&vm_page_queue_free_mtx); 763 while ((rv = LIST_FIRST(&object->rvq)) != NULL) { 764 KASSERT(rv->object == object, 765 ("vm_reserv_break_all: reserv %p is corrupted", rv)); 766 if (rv->inpartpopq) { 767 TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); 768 rv->inpartpopq = FALSE; 769 } 770 vm_reserv_break(rv, NULL); 771 } 772 mtx_unlock(&vm_page_queue_free_mtx); 773 } 774 775 /* 776 * Frees the given page if it belongs to a reservation. Returns TRUE if the 777 * page is freed and FALSE otherwise. 778 * 779 * The free page queue lock must be held. 780 */ 781 boolean_t 782 vm_reserv_free_page(vm_page_t m) 783 { 784 vm_reserv_t rv; 785 786 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 787 rv = vm_reserv_from_page(m); 788 if (rv->object == NULL) 789 return (FALSE); 790 if ((m->flags & PG_CACHED) != 0 && m->pool != VM_FREEPOOL_CACHE) 791 vm_phys_set_pool(VM_FREEPOOL_CACHE, rv->pages, 792 VM_LEVEL_0_ORDER); 793 vm_reserv_depopulate(rv, m - rv->pages); 794 return (TRUE); 795 } 796 797 /* 798 * Initializes the reservation management system. Specifically, initializes 799 * the reservation array. 800 * 801 * Requires that vm_page_array and first_page are initialized! 802 */ 803 void 804 vm_reserv_init(void) 805 { 806 vm_paddr_t paddr; 807 int i; 808 809 /* 810 * Initialize the reservation array. Specifically, initialize the 811 * "pages" field for every element that has an underlying superpage. 812 */ 813 for (i = 0; phys_avail[i + 1] != 0; i += 2) { 814 paddr = roundup2(phys_avail[i], VM_LEVEL_0_SIZE); 815 while (paddr + VM_LEVEL_0_SIZE <= phys_avail[i + 1]) { 816 vm_reserv_array[paddr >> VM_LEVEL_0_SHIFT].pages = 817 PHYS_TO_VM_PAGE(paddr); 818 paddr += VM_LEVEL_0_SIZE; 819 } 820 } 821 } 822 823 /* 824 * Returns a reservation level if the given page belongs to a fully-populated 825 * reservation and -1 otherwise. 826 */ 827 int 828 vm_reserv_level_iffullpop(vm_page_t m) 829 { 830 vm_reserv_t rv; 831 832 rv = vm_reserv_from_page(m); 833 return (rv->popcnt == VM_LEVEL_0_NPAGES ? 0 : -1); 834 } 835 836 /* 837 * Prepare for the reactivation of a cached page. 838 * 839 * First, suppose that the given page "m" was allocated individually, i.e., not 840 * as part of a reservation, and cached. Then, suppose a reservation 841 * containing "m" is allocated by the same object. Although "m" and the 842 * reservation belong to the same object, "m"'s pindex may not match the 843 * reservation's. 844 * 845 * The free page queue must be locked. 846 */ 847 boolean_t 848 vm_reserv_reactivate_page(vm_page_t m) 849 { 850 vm_reserv_t rv; 851 int index; 852 853 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 854 rv = vm_reserv_from_page(m); 855 if (rv->object == NULL) 856 return (FALSE); 857 KASSERT((m->flags & PG_CACHED) != 0, 858 ("vm_reserv_reactivate_page: page %p is not cached", m)); 859 if (m->object == rv->object && 860 m->pindex - rv->pindex == (index = VM_RESERV_INDEX(m->object, 861 m->pindex))) 862 vm_reserv_populate(rv, index); 863 else { 864 KASSERT(rv->inpartpopq, 865 ("vm_reserv_reactivate_page: reserv %p's inpartpopq is FALSE", 866 rv)); 867 TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); 868 rv->inpartpopq = FALSE; 869 /* Don't release "m" to the physical memory allocator. */ 870 vm_reserv_break(rv, m); 871 } 872 return (TRUE); 873 } 874 875 /* 876 * Breaks the given partially-populated reservation, releasing its cached and 877 * free pages to the physical memory allocator. 878 * 879 * The free page queue lock must be held. 880 */ 881 static void 882 vm_reserv_reclaim(vm_reserv_t rv) 883 { 884 885 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 886 KASSERT(rv->inpartpopq, 887 ("vm_reserv_reclaim: reserv %p's inpartpopq is FALSE", rv)); 888 TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); 889 rv->inpartpopq = FALSE; 890 vm_reserv_break(rv, NULL); 891 vm_reserv_reclaimed++; 892 } 893 894 /* 895 * Breaks the reservation at the head of the partially-populated reservation 896 * queue, releasing its cached and free pages to the physical memory 897 * allocator. Returns TRUE if a reservation is broken and FALSE otherwise. 898 * 899 * The free page queue lock must be held. 900 */ 901 boolean_t 902 vm_reserv_reclaim_inactive(void) 903 { 904 vm_reserv_t rv; 905 906 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 907 if ((rv = TAILQ_FIRST(&vm_rvq_partpop)) != NULL) { 908 vm_reserv_reclaim(rv); 909 return (TRUE); 910 } 911 return (FALSE); 912 } 913 914 /* 915 * Searches the partially-populated reservation queue for the least recently 916 * active reservation with unused pages, i.e., cached or free, that satisfy the 917 * given request for contiguous physical memory. If a satisfactory reservation 918 * is found, it is broken. Returns TRUE if a reservation is broken and FALSE 919 * otherwise. 920 * 921 * The free page queue lock must be held. 922 */ 923 boolean_t 924 vm_reserv_reclaim_contig(u_long npages, vm_paddr_t low, vm_paddr_t high, 925 u_long alignment, vm_paddr_t boundary) 926 { 927 vm_paddr_t pa, size; 928 vm_reserv_t rv; 929 int hi, i, lo, next_free; 930 931 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 932 if (npages > VM_LEVEL_0_NPAGES - 1) 933 return (FALSE); 934 size = npages << PAGE_SHIFT; 935 TAILQ_FOREACH(rv, &vm_rvq_partpop, partpopq) { 936 pa = VM_PAGE_TO_PHYS(&rv->pages[VM_LEVEL_0_NPAGES - 1]); 937 if (pa + PAGE_SIZE - size < low) { 938 /* This entire reservation is too low; go to next. */ 939 continue; 940 } 941 pa = VM_PAGE_TO_PHYS(&rv->pages[0]); 942 if (pa + size > high) { 943 /* This entire reservation is too high; go to next. */ 944 continue; 945 } 946 if (pa < low) { 947 /* Start the search for free pages at "low". */ 948 i = (low - pa) / NBPOPMAP; 949 hi = (low - pa) % NBPOPMAP; 950 } else 951 i = hi = 0; 952 do { 953 /* Find the next free page. */ 954 lo = ffsl(~(((1UL << hi) - 1) | rv->popmap[i])); 955 while (lo == 0 && ++i < NPOPMAP) 956 lo = ffsl(~rv->popmap[i]); 957 if (i == NPOPMAP) 958 break; 959 /* Convert from ffsl() to ordinary bit numbering. */ 960 lo--; 961 next_free = NBPOPMAP * i + lo; 962 pa = VM_PAGE_TO_PHYS(&rv->pages[next_free]); 963 KASSERT(pa >= low, 964 ("vm_reserv_reclaim_contig: pa is too low")); 965 if (pa + size > high) { 966 /* The rest of this reservation is too high. */ 967 break; 968 } else if ((pa & (alignment - 1)) != 0 || 969 ((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0) { 970 /* Continue with this reservation. */ 971 hi = lo; 972 continue; 973 } 974 /* Find the next used page. */ 975 hi = ffsl(rv->popmap[i] & ~((1UL << lo) - 1)); 976 while (hi == 0 && ++i < NPOPMAP) { 977 if ((NBPOPMAP * i - next_free) * PAGE_SIZE >= 978 size) { 979 vm_reserv_reclaim(rv); 980 return (TRUE); 981 } 982 hi = ffsl(rv->popmap[i]); 983 } 984 /* Convert from ffsl() to ordinary bit numbering. */ 985 if (i != NPOPMAP) 986 hi--; 987 if ((NBPOPMAP * i + hi - next_free) * PAGE_SIZE >= 988 size) { 989 vm_reserv_reclaim(rv); 990 return (TRUE); 991 } 992 } while (i < NPOPMAP); 993 } 994 return (FALSE); 995 } 996 997 /* 998 * Transfers the reservation underlying the given page to a new object. 999 * 1000 * The object must be locked. 1001 */ 1002 void 1003 vm_reserv_rename(vm_page_t m, vm_object_t new_object, vm_object_t old_object, 1004 vm_pindex_t old_object_offset) 1005 { 1006 vm_reserv_t rv; 1007 1008 VM_OBJECT_ASSERT_WLOCKED(new_object); 1009 rv = vm_reserv_from_page(m); 1010 if (rv->object == old_object) { 1011 mtx_lock(&vm_page_queue_free_mtx); 1012 if (rv->object == old_object) { 1013 LIST_REMOVE(rv, objq); 1014 LIST_INSERT_HEAD(&new_object->rvq, rv, objq); 1015 rv->object = new_object; 1016 rv->pindex -= old_object_offset; 1017 } 1018 mtx_unlock(&vm_page_queue_free_mtx); 1019 } 1020 } 1021 1022 /* 1023 * Allocates the virtual and physical memory required by the reservation 1024 * management system's data structures, in particular, the reservation array. 1025 */ 1026 vm_paddr_t 1027 vm_reserv_startup(vm_offset_t *vaddr, vm_paddr_t end, vm_paddr_t high_water) 1028 { 1029 vm_paddr_t new_end; 1030 size_t size; 1031 1032 /* 1033 * Calculate the size (in bytes) of the reservation array. Round up 1034 * from "high_water" because every small page is mapped to an element 1035 * in the reservation array based on its physical address. Thus, the 1036 * number of elements in the reservation array can be greater than the 1037 * number of superpages. 1038 */ 1039 size = howmany(high_water, VM_LEVEL_0_SIZE) * sizeof(struct vm_reserv); 1040 1041 /* 1042 * Allocate and map the physical memory for the reservation array. The 1043 * next available virtual address is returned by reference. 1044 */ 1045 new_end = end - round_page(size); 1046 vm_reserv_array = (void *)(uintptr_t)pmap_map(vaddr, new_end, end, 1047 VM_PROT_READ | VM_PROT_WRITE); 1048 bzero(vm_reserv_array, size); 1049 1050 /* 1051 * Return the next available physical address. 1052 */ 1053 return (new_end); 1054 } 1055 1056 #endif /* VM_NRESERVLEVEL > 0 */ 1057