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 sbuf_putc(&sbuf, 0); /* nullterm */ 265 error = sbuf_finish(&sbuf); 266 sbuf_delete(&sbuf); 267 return (error); 268 } 269 270 /* 271 * Reduces the given reservation's population count. If the population count 272 * becomes zero, the reservation is destroyed. Additionally, moves the 273 * reservation to the tail of the partially-populated reservation queue if the 274 * population count is non-zero. 275 * 276 * The free page queue lock must be held. 277 */ 278 static void 279 vm_reserv_depopulate(vm_reserv_t rv, int index) 280 { 281 282 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 283 KASSERT(rv->object != NULL, 284 ("vm_reserv_depopulate: reserv %p is free", rv)); 285 KASSERT(popmap_is_set(rv->popmap, index), 286 ("vm_reserv_depopulate: reserv %p's popmap[%d] is clear", rv, 287 index)); 288 KASSERT(rv->popcnt > 0, 289 ("vm_reserv_depopulate: reserv %p's popcnt is corrupted", rv)); 290 if (rv->inpartpopq) { 291 TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); 292 rv->inpartpopq = FALSE; 293 } else { 294 KASSERT(rv->pages->psind == 1, 295 ("vm_reserv_depopulate: reserv %p is already demoted", 296 rv)); 297 rv->pages->psind = 0; 298 } 299 popmap_clear(rv->popmap, index); 300 rv->popcnt--; 301 if (rv->popcnt == 0) { 302 LIST_REMOVE(rv, objq); 303 rv->object = NULL; 304 vm_phys_free_pages(rv->pages, VM_LEVEL_0_ORDER); 305 vm_reserv_freed++; 306 } else { 307 rv->inpartpopq = TRUE; 308 TAILQ_INSERT_TAIL(&vm_rvq_partpop, rv, partpopq); 309 } 310 } 311 312 /* 313 * Returns the reservation to which the given page might belong. 314 */ 315 static __inline vm_reserv_t 316 vm_reserv_from_page(vm_page_t m) 317 { 318 319 return (&vm_reserv_array[VM_PAGE_TO_PHYS(m) >> VM_LEVEL_0_SHIFT]); 320 } 321 322 /* 323 * Returns TRUE if the given reservation contains the given page index and 324 * FALSE otherwise. 325 */ 326 static __inline boolean_t 327 vm_reserv_has_pindex(vm_reserv_t rv, vm_pindex_t pindex) 328 { 329 330 return (((pindex - rv->pindex) & ~(VM_LEVEL_0_NPAGES - 1)) == 0); 331 } 332 333 /* 334 * Increases the given reservation's population count. Moves the reservation 335 * to the tail of the partially-populated reservation queue. 336 * 337 * The free page queue must be locked. 338 */ 339 static void 340 vm_reserv_populate(vm_reserv_t rv, int index) 341 { 342 343 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 344 KASSERT(rv->object != NULL, 345 ("vm_reserv_populate: reserv %p is free", rv)); 346 KASSERT(popmap_is_clear(rv->popmap, index), 347 ("vm_reserv_populate: reserv %p's popmap[%d] is set", rv, 348 index)); 349 KASSERT(rv->popcnt < VM_LEVEL_0_NPAGES, 350 ("vm_reserv_populate: reserv %p is already full", rv)); 351 KASSERT(rv->pages->psind == 0, 352 ("vm_reserv_populate: reserv %p is already promoted", rv)); 353 if (rv->inpartpopq) { 354 TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); 355 rv->inpartpopq = FALSE; 356 } 357 popmap_set(rv->popmap, index); 358 rv->popcnt++; 359 if (rv->popcnt < VM_LEVEL_0_NPAGES) { 360 rv->inpartpopq = TRUE; 361 TAILQ_INSERT_TAIL(&vm_rvq_partpop, rv, partpopq); 362 } else 363 rv->pages->psind = 1; 364 } 365 366 /* 367 * Allocates a contiguous set of physical pages of the given size "npages" 368 * from existing or newly created reservations. All of the physical pages 369 * must be at or above the given physical address "low" and below the given 370 * physical address "high". The given value "alignment" determines the 371 * alignment of the first physical page in the set. If the given value 372 * "boundary" is non-zero, then the set of physical pages cannot cross any 373 * physical address boundary that is a multiple of that value. Both 374 * "alignment" and "boundary" must be a power of two. 375 * 376 * The object and free page queue must be locked. 377 */ 378 vm_page_t 379 vm_reserv_alloc_contig(vm_object_t object, vm_pindex_t pindex, u_long npages, 380 vm_paddr_t low, vm_paddr_t high, u_long alignment, vm_paddr_t boundary) 381 { 382 vm_paddr_t pa, size; 383 vm_page_t m, m_ret, mpred, msucc; 384 vm_pindex_t first, leftcap, rightcap; 385 vm_reserv_t rv; 386 u_long allocpages, maxpages, minpages; 387 int i, index, n; 388 389 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 390 VM_OBJECT_ASSERT_WLOCKED(object); 391 KASSERT(npages != 0, ("vm_reserv_alloc_contig: npages is 0")); 392 393 /* 394 * Is a reservation fundamentally impossible? 395 */ 396 if (pindex < VM_RESERV_INDEX(object, pindex) || 397 pindex + npages > object->size) 398 return (NULL); 399 400 /* 401 * All reservations of a particular size have the same alignment. 402 * Assuming that the first page is allocated from a reservation, the 403 * least significant bits of its physical address can be determined 404 * from its offset from the beginning of the reservation and the size 405 * of the reservation. 406 * 407 * Could the specified index within a reservation of the smallest 408 * possible size satisfy the alignment and boundary requirements? 409 */ 410 pa = VM_RESERV_INDEX(object, pindex) << PAGE_SHIFT; 411 if ((pa & (alignment - 1)) != 0) 412 return (NULL); 413 size = npages << PAGE_SHIFT; 414 if (((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0) 415 return (NULL); 416 417 /* 418 * Look for an existing reservation. 419 */ 420 mpred = vm_radix_lookup_le(&object->rtree, pindex); 421 if (mpred != NULL) { 422 KASSERT(mpred->pindex < pindex, 423 ("vm_reserv_alloc_contig: pindex already allocated")); 424 rv = vm_reserv_from_page(mpred); 425 if (rv->object == object && vm_reserv_has_pindex(rv, pindex)) 426 goto found; 427 msucc = TAILQ_NEXT(mpred, listq); 428 } else 429 msucc = TAILQ_FIRST(&object->memq); 430 if (msucc != NULL) { 431 KASSERT(msucc->pindex > pindex, 432 ("vm_reserv_alloc_contig: pindex already allocated")); 433 rv = vm_reserv_from_page(msucc); 434 if (rv->object == object && vm_reserv_has_pindex(rv, pindex)) 435 goto found; 436 } 437 438 /* 439 * Could at least one reservation fit between the first index to the 440 * left that can be used ("leftcap") and the first index to the right 441 * that cannot be used ("rightcap")? 442 */ 443 first = pindex - VM_RESERV_INDEX(object, pindex); 444 if (mpred != NULL) { 445 if ((rv = vm_reserv_from_page(mpred))->object != object) 446 leftcap = mpred->pindex + 1; 447 else 448 leftcap = rv->pindex + VM_LEVEL_0_NPAGES; 449 if (leftcap > first) 450 return (NULL); 451 } 452 minpages = VM_RESERV_INDEX(object, pindex) + npages; 453 maxpages = roundup2(minpages, VM_LEVEL_0_NPAGES); 454 allocpages = maxpages; 455 if (msucc != NULL) { 456 if ((rv = vm_reserv_from_page(msucc))->object != object) 457 rightcap = msucc->pindex; 458 else 459 rightcap = rv->pindex; 460 if (first + maxpages > rightcap) { 461 if (maxpages == VM_LEVEL_0_NPAGES) 462 return (NULL); 463 464 /* 465 * At least one reservation will fit between "leftcap" 466 * and "rightcap". However, a reservation for the 467 * last of the requested pages will not fit. Reduce 468 * the size of the upcoming allocation accordingly. 469 */ 470 allocpages = minpages; 471 } 472 } 473 474 /* 475 * Would the last new reservation extend past the end of the object? 476 */ 477 if (first + maxpages > object->size) { 478 /* 479 * Don't allocate the last new reservation if the object is a 480 * vnode or backed by another object that is a vnode. 481 */ 482 if (object->type == OBJT_VNODE || 483 (object->backing_object != NULL && 484 object->backing_object->type == OBJT_VNODE)) { 485 if (maxpages == VM_LEVEL_0_NPAGES) 486 return (NULL); 487 allocpages = minpages; 488 } 489 /* Speculate that the object may grow. */ 490 } 491 492 /* 493 * Allocate the physical pages. The alignment and boundary specified 494 * for this allocation may be different from the alignment and 495 * boundary specified for the requested pages. For instance, the 496 * specified index may not be the first page within the first new 497 * reservation. 498 */ 499 m = vm_phys_alloc_contig(allocpages, low, high, ulmax(alignment, 500 VM_LEVEL_0_SIZE), boundary > VM_LEVEL_0_SIZE ? boundary : 0); 501 if (m == NULL) 502 return (NULL); 503 504 /* 505 * The allocated physical pages always begin at a reservation 506 * boundary, but they do not always end at a reservation boundary. 507 * Initialize every reservation that is completely covered by the 508 * allocated physical pages. 509 */ 510 m_ret = NULL; 511 index = VM_RESERV_INDEX(object, pindex); 512 do { 513 rv = vm_reserv_from_page(m); 514 KASSERT(rv->pages == m, 515 ("vm_reserv_alloc_contig: reserv %p's pages is corrupted", 516 rv)); 517 KASSERT(rv->object == NULL, 518 ("vm_reserv_alloc_contig: reserv %p isn't free", rv)); 519 LIST_INSERT_HEAD(&object->rvq, rv, objq); 520 rv->object = object; 521 rv->pindex = first; 522 KASSERT(rv->popcnt == 0, 523 ("vm_reserv_alloc_contig: reserv %p's popcnt is corrupted", 524 rv)); 525 KASSERT(!rv->inpartpopq, 526 ("vm_reserv_alloc_contig: reserv %p's inpartpopq is TRUE", 527 rv)); 528 for (i = 0; i < NPOPMAP; i++) 529 KASSERT(rv->popmap[i] == 0, 530 ("vm_reserv_alloc_contig: reserv %p's popmap is corrupted", 531 rv)); 532 n = ulmin(VM_LEVEL_0_NPAGES - index, npages); 533 for (i = 0; i < n; i++) 534 vm_reserv_populate(rv, index + i); 535 npages -= n; 536 if (m_ret == NULL) { 537 m_ret = &rv->pages[index]; 538 index = 0; 539 } 540 m += VM_LEVEL_0_NPAGES; 541 first += VM_LEVEL_0_NPAGES; 542 allocpages -= VM_LEVEL_0_NPAGES; 543 } while (allocpages >= VM_LEVEL_0_NPAGES); 544 return (m_ret); 545 546 /* 547 * Found a matching reservation. 548 */ 549 found: 550 index = VM_RESERV_INDEX(object, pindex); 551 /* Does the allocation fit within the reservation? */ 552 if (index + npages > VM_LEVEL_0_NPAGES) 553 return (NULL); 554 m = &rv->pages[index]; 555 pa = VM_PAGE_TO_PHYS(m); 556 if (pa < low || pa + size > high || (pa & (alignment - 1)) != 0 || 557 ((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0) 558 return (NULL); 559 /* Handle vm_page_rename(m, new_object, ...). */ 560 for (i = 0; i < npages; i++) 561 if (popmap_is_set(rv->popmap, index + i)) 562 return (NULL); 563 for (i = 0; i < npages; i++) 564 vm_reserv_populate(rv, index + i); 565 return (m); 566 } 567 568 /* 569 * Allocates a page from an existing or newly-created reservation. 570 * 571 * The page "mpred" must immediately precede the offset "pindex" within the 572 * specified object. 573 * 574 * The object and free page queue must be locked. 575 */ 576 vm_page_t 577 vm_reserv_alloc_page(vm_object_t object, vm_pindex_t pindex, vm_page_t mpred) 578 { 579 vm_page_t m, msucc; 580 vm_pindex_t first, leftcap, rightcap; 581 vm_reserv_t rv; 582 int i, index; 583 584 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 585 VM_OBJECT_ASSERT_WLOCKED(object); 586 587 /* 588 * Is a reservation fundamentally impossible? 589 */ 590 if (pindex < VM_RESERV_INDEX(object, pindex) || 591 pindex >= object->size) 592 return (NULL); 593 594 /* 595 * Look for an existing reservation. 596 */ 597 if (mpred != NULL) { 598 KASSERT(mpred->object == object, 599 ("vm_reserv_alloc_page: object doesn't contain mpred")); 600 KASSERT(mpred->pindex < pindex, 601 ("vm_reserv_alloc_page: mpred doesn't precede pindex")); 602 rv = vm_reserv_from_page(mpred); 603 if (rv->object == object && vm_reserv_has_pindex(rv, pindex)) 604 goto found; 605 msucc = TAILQ_NEXT(mpred, listq); 606 } else 607 msucc = TAILQ_FIRST(&object->memq); 608 if (msucc != NULL) { 609 KASSERT(msucc->pindex > pindex, 610 ("vm_reserv_alloc_page: msucc doesn't succeed pindex")); 611 rv = vm_reserv_from_page(msucc); 612 if (rv->object == object && vm_reserv_has_pindex(rv, pindex)) 613 goto found; 614 } 615 616 /* 617 * Could a reservation fit between the first index to the left that 618 * can be used and the first index to the right that cannot be used? 619 */ 620 first = pindex - VM_RESERV_INDEX(object, pindex); 621 if (mpred != NULL) { 622 if ((rv = vm_reserv_from_page(mpred))->object != object) 623 leftcap = mpred->pindex + 1; 624 else 625 leftcap = rv->pindex + VM_LEVEL_0_NPAGES; 626 if (leftcap > first) 627 return (NULL); 628 } 629 if (msucc != NULL) { 630 if ((rv = vm_reserv_from_page(msucc))->object != object) 631 rightcap = msucc->pindex; 632 else 633 rightcap = rv->pindex; 634 if (first + VM_LEVEL_0_NPAGES > rightcap) 635 return (NULL); 636 } 637 638 /* 639 * Would a new reservation extend past the end of the object? 640 */ 641 if (first + VM_LEVEL_0_NPAGES > object->size) { 642 /* 643 * Don't allocate a new reservation if the object is a vnode or 644 * backed by another object that is a vnode. 645 */ 646 if (object->type == OBJT_VNODE || 647 (object->backing_object != NULL && 648 object->backing_object->type == OBJT_VNODE)) 649 return (NULL); 650 /* Speculate that the object may grow. */ 651 } 652 653 /* 654 * Allocate and populate the new reservation. 655 */ 656 m = vm_phys_alloc_pages(VM_FREEPOOL_DEFAULT, VM_LEVEL_0_ORDER); 657 if (m == NULL) 658 return (NULL); 659 rv = vm_reserv_from_page(m); 660 KASSERT(rv->pages == m, 661 ("vm_reserv_alloc_page: reserv %p's pages is corrupted", rv)); 662 KASSERT(rv->object == NULL, 663 ("vm_reserv_alloc_page: reserv %p isn't free", rv)); 664 LIST_INSERT_HEAD(&object->rvq, rv, objq); 665 rv->object = object; 666 rv->pindex = first; 667 KASSERT(rv->popcnt == 0, 668 ("vm_reserv_alloc_page: reserv %p's popcnt is corrupted", rv)); 669 KASSERT(!rv->inpartpopq, 670 ("vm_reserv_alloc_page: reserv %p's inpartpopq is TRUE", rv)); 671 for (i = 0; i < NPOPMAP; i++) 672 KASSERT(rv->popmap[i] == 0, 673 ("vm_reserv_alloc_page: reserv %p's popmap is corrupted", 674 rv)); 675 index = VM_RESERV_INDEX(object, pindex); 676 vm_reserv_populate(rv, index); 677 return (&rv->pages[index]); 678 679 /* 680 * Found a matching reservation. 681 */ 682 found: 683 index = VM_RESERV_INDEX(object, pindex); 684 m = &rv->pages[index]; 685 /* Handle vm_page_rename(m, new_object, ...). */ 686 if (popmap_is_set(rv->popmap, index)) 687 return (NULL); 688 vm_reserv_populate(rv, index); 689 return (m); 690 } 691 692 /* 693 * Breaks the given reservation. Except for the specified cached or free 694 * page, all cached and free pages in the reservation are returned to the 695 * physical memory allocator. The reservation's population count and map are 696 * reset to their initial state. 697 * 698 * The given reservation must not be in the partially-populated reservation 699 * queue. The free page queue lock must be held. 700 */ 701 static void 702 vm_reserv_break(vm_reserv_t rv, vm_page_t m) 703 { 704 int begin_zeroes, hi, i, lo; 705 706 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 707 KASSERT(rv->object != NULL, 708 ("vm_reserv_break: reserv %p is free", rv)); 709 KASSERT(!rv->inpartpopq, 710 ("vm_reserv_break: reserv %p's inpartpopq is TRUE", rv)); 711 LIST_REMOVE(rv, objq); 712 rv->object = NULL; 713 if (m != NULL) { 714 /* 715 * Since the reservation is being broken, there is no harm in 716 * abusing the population map to stop "m" from being returned 717 * to the physical memory allocator. 718 */ 719 i = m - rv->pages; 720 KASSERT(popmap_is_clear(rv->popmap, i), 721 ("vm_reserv_break: reserv %p's popmap is corrupted", rv)); 722 popmap_set(rv->popmap, i); 723 rv->popcnt++; 724 } 725 i = hi = 0; 726 do { 727 /* Find the next 0 bit. Any previous 0 bits are < "hi". */ 728 lo = ffsl(~(((1UL << hi) - 1) | rv->popmap[i])); 729 if (lo == 0) { 730 /* Redundantly clears bits < "hi". */ 731 rv->popmap[i] = 0; 732 rv->popcnt -= NBPOPMAP - hi; 733 while (++i < NPOPMAP) { 734 lo = ffsl(~rv->popmap[i]); 735 if (lo == 0) { 736 rv->popmap[i] = 0; 737 rv->popcnt -= NBPOPMAP; 738 } else 739 break; 740 } 741 if (i == NPOPMAP) 742 break; 743 hi = 0; 744 } 745 KASSERT(lo > 0, ("vm_reserv_break: lo is %d", lo)); 746 /* Convert from ffsl() to ordinary bit numbering. */ 747 lo--; 748 if (lo > 0) { 749 /* Redundantly clears bits < "hi". */ 750 rv->popmap[i] &= ~((1UL << lo) - 1); 751 rv->popcnt -= lo - hi; 752 } 753 begin_zeroes = NBPOPMAP * i + lo; 754 /* Find the next 1 bit. */ 755 do 756 hi = ffsl(rv->popmap[i]); 757 while (hi == 0 && ++i < NPOPMAP); 758 if (i != NPOPMAP) 759 /* Convert from ffsl() to ordinary bit numbering. */ 760 hi--; 761 vm_phys_free_contig(&rv->pages[begin_zeroes], NBPOPMAP * i + 762 hi - begin_zeroes); 763 } while (i < NPOPMAP); 764 KASSERT(rv->popcnt == 0, 765 ("vm_reserv_break: reserv %p's popcnt is corrupted", rv)); 766 vm_reserv_broken++; 767 } 768 769 /* 770 * Breaks all reservations belonging to the given object. 771 */ 772 void 773 vm_reserv_break_all(vm_object_t object) 774 { 775 vm_reserv_t rv; 776 777 mtx_lock(&vm_page_queue_free_mtx); 778 while ((rv = LIST_FIRST(&object->rvq)) != NULL) { 779 KASSERT(rv->object == object, 780 ("vm_reserv_break_all: reserv %p is corrupted", rv)); 781 if (rv->inpartpopq) { 782 TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); 783 rv->inpartpopq = FALSE; 784 } 785 vm_reserv_break(rv, NULL); 786 } 787 mtx_unlock(&vm_page_queue_free_mtx); 788 } 789 790 /* 791 * Frees the given page if it belongs to a reservation. Returns TRUE if the 792 * page is freed and FALSE otherwise. 793 * 794 * The free page queue lock must be held. 795 */ 796 boolean_t 797 vm_reserv_free_page(vm_page_t m) 798 { 799 vm_reserv_t rv; 800 801 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 802 rv = vm_reserv_from_page(m); 803 if (rv->object == NULL) 804 return (FALSE); 805 if ((m->flags & PG_CACHED) != 0 && m->pool != VM_FREEPOOL_CACHE) 806 vm_phys_set_pool(VM_FREEPOOL_CACHE, rv->pages, 807 VM_LEVEL_0_ORDER); 808 vm_reserv_depopulate(rv, m - rv->pages); 809 return (TRUE); 810 } 811 812 /* 813 * Initializes the reservation management system. Specifically, initializes 814 * the reservation array. 815 * 816 * Requires that vm_page_array and first_page are initialized! 817 */ 818 void 819 vm_reserv_init(void) 820 { 821 vm_paddr_t paddr; 822 struct vm_phys_seg *seg; 823 int segind; 824 825 /* 826 * Initialize the reservation array. Specifically, initialize the 827 * "pages" field for every element that has an underlying superpage. 828 */ 829 for (segind = 0; segind < vm_phys_nsegs; segind++) { 830 seg = &vm_phys_segs[segind]; 831 paddr = roundup2(seg->start, VM_LEVEL_0_SIZE); 832 while (paddr + VM_LEVEL_0_SIZE <= seg->end) { 833 vm_reserv_array[paddr >> VM_LEVEL_0_SHIFT].pages = 834 PHYS_TO_VM_PAGE(paddr); 835 paddr += VM_LEVEL_0_SIZE; 836 } 837 } 838 } 839 840 /* 841 * Returns a reservation level if the given page belongs to a fully-populated 842 * reservation and -1 otherwise. 843 */ 844 int 845 vm_reserv_level_iffullpop(vm_page_t m) 846 { 847 vm_reserv_t rv; 848 849 rv = vm_reserv_from_page(m); 850 return (rv->popcnt == VM_LEVEL_0_NPAGES ? 0 : -1); 851 } 852 853 /* 854 * Prepare for the reactivation of a cached page. 855 * 856 * First, suppose that the given page "m" was allocated individually, i.e., not 857 * as part of a reservation, and cached. Then, suppose a reservation 858 * containing "m" is allocated by the same object. Although "m" and the 859 * reservation belong to the same object, "m"'s pindex may not match the 860 * reservation's. 861 * 862 * The free page queue must be locked. 863 */ 864 boolean_t 865 vm_reserv_reactivate_page(vm_page_t m) 866 { 867 vm_reserv_t rv; 868 int index; 869 870 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 871 rv = vm_reserv_from_page(m); 872 if (rv->object == NULL) 873 return (FALSE); 874 KASSERT((m->flags & PG_CACHED) != 0, 875 ("vm_reserv_reactivate_page: page %p is not cached", m)); 876 if (m->object == rv->object && 877 m->pindex - rv->pindex == (index = VM_RESERV_INDEX(m->object, 878 m->pindex))) 879 vm_reserv_populate(rv, index); 880 else { 881 KASSERT(rv->inpartpopq, 882 ("vm_reserv_reactivate_page: reserv %p's inpartpopq is FALSE", 883 rv)); 884 TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); 885 rv->inpartpopq = FALSE; 886 /* Don't release "m" to the physical memory allocator. */ 887 vm_reserv_break(rv, m); 888 } 889 return (TRUE); 890 } 891 892 /* 893 * Breaks the given partially-populated reservation, releasing its cached and 894 * free pages to the physical memory allocator. 895 * 896 * The free page queue lock must be held. 897 */ 898 static void 899 vm_reserv_reclaim(vm_reserv_t rv) 900 { 901 902 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 903 KASSERT(rv->inpartpopq, 904 ("vm_reserv_reclaim: reserv %p's inpartpopq is FALSE", rv)); 905 TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); 906 rv->inpartpopq = FALSE; 907 vm_reserv_break(rv, NULL); 908 vm_reserv_reclaimed++; 909 } 910 911 /* 912 * Breaks the reservation at the head of the partially-populated reservation 913 * queue, releasing its cached and free pages to the physical memory 914 * allocator. Returns TRUE if a reservation is broken and FALSE otherwise. 915 * 916 * The free page queue lock must be held. 917 */ 918 boolean_t 919 vm_reserv_reclaim_inactive(void) 920 { 921 vm_reserv_t rv; 922 923 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 924 if ((rv = TAILQ_FIRST(&vm_rvq_partpop)) != NULL) { 925 vm_reserv_reclaim(rv); 926 return (TRUE); 927 } 928 return (FALSE); 929 } 930 931 /* 932 * Searches the partially-populated reservation queue for the least recently 933 * active reservation with unused pages, i.e., cached or free, that satisfy the 934 * given request for contiguous physical memory. If a satisfactory reservation 935 * is found, it is broken. Returns TRUE if a reservation is broken and FALSE 936 * otherwise. 937 * 938 * The free page queue lock must be held. 939 */ 940 boolean_t 941 vm_reserv_reclaim_contig(u_long npages, vm_paddr_t low, vm_paddr_t high, 942 u_long alignment, vm_paddr_t boundary) 943 { 944 vm_paddr_t pa, size; 945 vm_reserv_t rv; 946 int hi, i, lo, next_free; 947 948 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 949 if (npages > VM_LEVEL_0_NPAGES - 1) 950 return (FALSE); 951 size = npages << PAGE_SHIFT; 952 TAILQ_FOREACH(rv, &vm_rvq_partpop, partpopq) { 953 pa = VM_PAGE_TO_PHYS(&rv->pages[VM_LEVEL_0_NPAGES - 1]); 954 if (pa + PAGE_SIZE - size < low) { 955 /* This entire reservation is too low; go to next. */ 956 continue; 957 } 958 pa = VM_PAGE_TO_PHYS(&rv->pages[0]); 959 if (pa + size > high) { 960 /* This entire reservation is too high; go to next. */ 961 continue; 962 } 963 if (pa < low) { 964 /* Start the search for free pages at "low". */ 965 i = (low - pa) / NBPOPMAP; 966 hi = (low - pa) % NBPOPMAP; 967 } else 968 i = hi = 0; 969 do { 970 /* Find the next free page. */ 971 lo = ffsl(~(((1UL << hi) - 1) | rv->popmap[i])); 972 while (lo == 0 && ++i < NPOPMAP) 973 lo = ffsl(~rv->popmap[i]); 974 if (i == NPOPMAP) 975 break; 976 /* Convert from ffsl() to ordinary bit numbering. */ 977 lo--; 978 next_free = NBPOPMAP * i + lo; 979 pa = VM_PAGE_TO_PHYS(&rv->pages[next_free]); 980 KASSERT(pa >= low, 981 ("vm_reserv_reclaim_contig: pa is too low")); 982 if (pa + size > high) { 983 /* The rest of this reservation is too high. */ 984 break; 985 } else if ((pa & (alignment - 1)) != 0 || 986 ((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0) { 987 /* Continue with this reservation. */ 988 hi = lo; 989 continue; 990 } 991 /* Find the next used page. */ 992 hi = ffsl(rv->popmap[i] & ~((1UL << lo) - 1)); 993 while (hi == 0 && ++i < NPOPMAP) { 994 if ((NBPOPMAP * i - next_free) * PAGE_SIZE >= 995 size) { 996 vm_reserv_reclaim(rv); 997 return (TRUE); 998 } 999 hi = ffsl(rv->popmap[i]); 1000 } 1001 /* Convert from ffsl() to ordinary bit numbering. */ 1002 if (i != NPOPMAP) 1003 hi--; 1004 if ((NBPOPMAP * i + hi - next_free) * PAGE_SIZE >= 1005 size) { 1006 vm_reserv_reclaim(rv); 1007 return (TRUE); 1008 } 1009 } while (i < NPOPMAP); 1010 } 1011 return (FALSE); 1012 } 1013 1014 /* 1015 * Transfers the reservation underlying the given page to a new object. 1016 * 1017 * The object must be locked. 1018 */ 1019 void 1020 vm_reserv_rename(vm_page_t m, vm_object_t new_object, vm_object_t old_object, 1021 vm_pindex_t old_object_offset) 1022 { 1023 vm_reserv_t rv; 1024 1025 VM_OBJECT_ASSERT_WLOCKED(new_object); 1026 rv = vm_reserv_from_page(m); 1027 if (rv->object == old_object) { 1028 mtx_lock(&vm_page_queue_free_mtx); 1029 if (rv->object == old_object) { 1030 LIST_REMOVE(rv, objq); 1031 LIST_INSERT_HEAD(&new_object->rvq, rv, objq); 1032 rv->object = new_object; 1033 rv->pindex -= old_object_offset; 1034 } 1035 mtx_unlock(&vm_page_queue_free_mtx); 1036 } 1037 } 1038 1039 /* 1040 * Allocates the virtual and physical memory required by the reservation 1041 * management system's data structures, in particular, the reservation array. 1042 */ 1043 vm_paddr_t 1044 vm_reserv_startup(vm_offset_t *vaddr, vm_paddr_t end, vm_paddr_t high_water) 1045 { 1046 vm_paddr_t new_end; 1047 size_t size; 1048 1049 /* 1050 * Calculate the size (in bytes) of the reservation array. Round up 1051 * from "high_water" because every small page is mapped to an element 1052 * in the reservation array based on its physical address. Thus, the 1053 * number of elements in the reservation array can be greater than the 1054 * number of superpages. 1055 */ 1056 size = howmany(high_water, VM_LEVEL_0_SIZE) * sizeof(struct vm_reserv); 1057 1058 /* 1059 * Allocate and map the physical memory for the reservation array. The 1060 * next available virtual address is returned by reference. 1061 */ 1062 new_end = end - round_page(size); 1063 vm_reserv_array = (void *)(uintptr_t)pmap_map(vaddr, new_end, end, 1064 VM_PROT_READ | VM_PROT_WRITE); 1065 bzero(vm_reserv_array, size); 1066 1067 /* 1068 * Return the next available physical address. 1069 */ 1070 return (new_end); 1071 } 1072 1073 #endif /* VM_NRESERVLEVEL > 0 */ 1074