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