Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_reserv.c
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1 /*- 2 * Copyright (c) 2002-2006 Rice University 3 * Copyright (c) 2007-2008 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 36 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 39 #include "opt_vm.h" 40 41 #include <sys/param.h> 42 #include <sys/kernel.h> 43 #include <sys/lock.h> 44 #include <sys/malloc.h> 45 #include <sys/mutex.h> 46 #include <sys/queue.h> 47 #include <sys/sbuf.h> 48 #include <sys/sysctl.h> 49 #include <sys/systm.h> 50 51 #include <vm/vm.h> 52 #include <vm/vm_param.h> 53 #include <vm/vm_object.h> 54 #include <vm/vm_page.h> 55 #include <vm/vm_phys.h> 56 #include <vm/vm_reserv.h> 57 58 /* 59 * The reservation system supports the speculative allocation of large physical 60 * pages ("superpages"). Speculative allocation enables the fully-automatic 61 * utilization of superpages by the virtual memory system. In other words, no 62 * programmatic directives are required to use superpages. 63 */ 64 65 #if VM_NRESERVLEVEL > 0 66 67 /* 68 * The number of small pages that are contained in a level 0 reservation 69 */ 70 #define VM_LEVEL_0_NPAGES (1 << VM_LEVEL_0_ORDER) 71 72 /* 73 * The number of bits by which a physical address is shifted to obtain the 74 * reservation number 75 */ 76 #define VM_LEVEL_0_SHIFT (VM_LEVEL_0_ORDER + PAGE_SHIFT) 77 78 /* 79 * The size of a level 0 reservation in bytes 80 */ 81 #define VM_LEVEL_0_SIZE (1 << VM_LEVEL_0_SHIFT) 82 83 /* 84 * Computes the index of the small page underlying the given (object, pindex) 85 * within the reservation's array of small pages. 86 */ 87 #define VM_RESERV_INDEX(object, pindex) \ 88 (((object)->pg_color + (pindex)) & (VM_LEVEL_0_NPAGES - 1)) 89 90 /* 91 * The reservation structure 92 * 93 * A reservation structure is constructed whenever a large physical page is 94 * speculatively allocated to an object. The reservation provides the small 95 * physical pages for the range [pindex, pindex + VM_LEVEL_0_NPAGES) of offsets 96 * within that object. The reservation's "popcnt" tracks the number of these 97 * small physical pages that are in use at any given time. When and if the 98 * reservation is not fully utilized, it appears in the queue of partially- 99 * populated reservations. The reservation always appears on the containing 100 * object's list of reservations. 101 * 102 * A partially-populated reservation can be broken and reclaimed at any time. 103 */ 104 struct vm_reserv { 105 TAILQ_ENTRY(vm_reserv) partpopq; 106 LIST_ENTRY(vm_reserv) objq; 107 vm_object_t object; /* containing object */ 108 vm_pindex_t pindex; /* offset within object */ 109 vm_page_t pages; /* first page of a superpage */ 110 int popcnt; /* # of pages in use */ 111 char inpartpopq; 112 }; 113 114 /* 115 * The reservation array 116 * 117 * This array is analoguous in function to vm_page_array. It differs in the 118 * respect that it may contain a greater number of useful reservation 119 * structures than there are (physical) superpages. These "invalid" 120 * reservation structures exist to trade-off space for time in the 121 * implementation of vm_reserv_from_page(). Invalid reservation structures are 122 * distinguishable from "valid" reservation structures by inspecting the 123 * reservation's "pages" field. Invalid reservation structures have a NULL 124 * "pages" field. 125 * 126 * vm_reserv_from_page() maps a small (physical) page to an element of this 127 * array by computing a physical reservation number from the page's physical 128 * address. The physical reservation number is used as the array index. 129 * 130 * An "active" reservation is a valid reservation structure that has a non-NULL 131 * "object" field and a non-zero "popcnt" field. In other words, every active 132 * reservation belongs to a particular object. Moreover, every active 133 * reservation has an entry in the containing object's list of reservations. 134 */ 135 static vm_reserv_t vm_reserv_array; 136 137 /* 138 * The partially-populated reservation queue 139 * 140 * This queue enables the fast recovery of an unused cached or free small page 141 * from a partially-populated reservation. The reservation at the head of 142 * this queue is the least-recently-changed, partially-populated reservation. 143 * 144 * Access to this queue is synchronized by the free page queue lock. 145 */ 146 static TAILQ_HEAD(, vm_reserv) vm_rvq_partpop = 147 TAILQ_HEAD_INITIALIZER(vm_rvq_partpop); 148 149 static SYSCTL_NODE(_vm, OID_AUTO, reserv, CTLFLAG_RD, 0, "Reservation Info"); 150 151 static long vm_reserv_broken; 152 SYSCTL_LONG(_vm_reserv, OID_AUTO, broken, CTLFLAG_RD, 153 &vm_reserv_broken, 0, "Cumulative number of broken reservations"); 154 155 static long vm_reserv_freed; 156 SYSCTL_LONG(_vm_reserv, OID_AUTO, freed, CTLFLAG_RD, 157 &vm_reserv_freed, 0, "Cumulative number of freed reservations"); 158 159 static int sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS); 160 161 SYSCTL_OID(_vm_reserv, OID_AUTO, partpopq, CTLTYPE_STRING | CTLFLAG_RD, NULL, 0, 162 sysctl_vm_reserv_partpopq, "A", "Partially-populated reservation queues"); 163 164 static long vm_reserv_reclaimed; 165 SYSCTL_LONG(_vm_reserv, OID_AUTO, reclaimed, CTLFLAG_RD, 166 &vm_reserv_reclaimed, 0, "Cumulative number of reclaimed reservations"); 167 168 static void vm_reserv_depopulate(vm_reserv_t rv); 169 static vm_reserv_t vm_reserv_from_page(vm_page_t m); 170 static boolean_t vm_reserv_has_pindex(vm_reserv_t rv, 171 vm_pindex_t pindex); 172 static void vm_reserv_populate(vm_reserv_t rv); 173 static void vm_reserv_reclaim(vm_reserv_t rv); 174 175 /* 176 * Describes the current state of the partially-populated reservation queue. 177 */ 178 static int 179 sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS) 180 { 181 struct sbuf sbuf; 182 vm_reserv_t rv; 183 char *cbuf; 184 const int cbufsize = (VM_NRESERVLEVEL + 1) * 81; 185 int counter, error, level, unused_pages; 186 187 cbuf = malloc(cbufsize, M_TEMP, M_WAITOK | M_ZERO); 188 sbuf_new(&sbuf, cbuf, cbufsize, SBUF_FIXEDLEN); 189 sbuf_printf(&sbuf, "\nLEVEL SIZE NUMBER\n\n"); 190 for (level = -1; level <= VM_NRESERVLEVEL - 2; level++) { 191 counter = 0; 192 unused_pages = 0; 193 mtx_lock(&vm_page_queue_free_mtx); 194 TAILQ_FOREACH(rv, &vm_rvq_partpop/*[level]*/, partpopq) { 195 counter++; 196 unused_pages += VM_LEVEL_0_NPAGES - rv->popcnt; 197 } 198 mtx_unlock(&vm_page_queue_free_mtx); 199 sbuf_printf(&sbuf, "%5d: %6dK, %6d\n", level, 200 unused_pages * ((int)PAGE_SIZE / 1024), counter); 201 } 202 sbuf_finish(&sbuf); 203 error = SYSCTL_OUT(req, sbuf_data(&sbuf), sbuf_len(&sbuf)); 204 sbuf_delete(&sbuf); 205 free(cbuf, M_TEMP); 206 return (error); 207 } 208 209 /* 210 * Reduces the given reservation's population count. If the population count 211 * becomes zero, the reservation is destroyed. Additionally, moves the 212 * reservation to the tail of the partially-populated reservations queue if the 213 * population count is non-zero. 214 * 215 * The free page queue lock must be held. 216 */ 217 static void 218 vm_reserv_depopulate(vm_reserv_t rv) 219 { 220 221 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 222 KASSERT(rv->object != NULL, 223 ("vm_reserv_depopulate: reserv %p is free", rv)); 224 KASSERT(rv->popcnt > 0, 225 ("vm_reserv_depopulate: reserv %p's popcnt is corrupted", rv)); 226 if (rv->inpartpopq) { 227 TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); 228 rv->inpartpopq = FALSE; 229 } 230 rv->popcnt--; 231 if (rv->popcnt == 0) { 232 LIST_REMOVE(rv, objq); 233 rv->object = NULL; 234 vm_phys_free_pages(rv->pages, VM_LEVEL_0_ORDER); 235 vm_reserv_freed++; 236 } else { 237 rv->inpartpopq = TRUE; 238 TAILQ_INSERT_TAIL(&vm_rvq_partpop, rv, partpopq); 239 } 240 } 241 242 /* 243 * Returns the reservation to which the given page might belong. 244 */ 245 static __inline vm_reserv_t 246 vm_reserv_from_page(vm_page_t m) 247 { 248 249 return (&vm_reserv_array[VM_PAGE_TO_PHYS(m) >> VM_LEVEL_0_SHIFT]); 250 } 251 252 /* 253 * Returns TRUE if the given reservation contains the given page index and 254 * FALSE otherwise. 255 */ 256 static __inline boolean_t 257 vm_reserv_has_pindex(vm_reserv_t rv, vm_pindex_t pindex) 258 { 259 260 return (((pindex - rv->pindex) & ~(VM_LEVEL_0_NPAGES - 1)) == 0); 261 } 262 263 /* 264 * Increases the given reservation's population count. Moves the reservation 265 * to the tail of the partially-populated reservation queue. 266 * 267 * The free page queue must be locked. 268 */ 269 static void 270 vm_reserv_populate(vm_reserv_t rv) 271 { 272 273 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 274 KASSERT(rv->object != NULL, 275 ("vm_reserv_populate: reserv %p is free", rv)); 276 KASSERT(rv->popcnt < VM_LEVEL_0_NPAGES, 277 ("vm_reserv_populate: reserv %p is already full", rv)); 278 if (rv->inpartpopq) { 279 TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); 280 rv->inpartpopq = FALSE; 281 } 282 rv->popcnt++; 283 if (rv->popcnt < VM_LEVEL_0_NPAGES) { 284 rv->inpartpopq = TRUE; 285 TAILQ_INSERT_TAIL(&vm_rvq_partpop, rv, partpopq); 286 } 287 } 288 289 /* 290 * Allocates a page from an existing or newly-created reservation. 291 * 292 * The object and free page queue must be locked. 293 */ 294 vm_page_t 295 vm_reserv_alloc_page(vm_object_t object, vm_pindex_t pindex) 296 { 297 vm_page_t m, mpred, msucc; 298 vm_pindex_t first, leftcap, rightcap; 299 vm_reserv_t rv; 300 301 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 302 303 /* 304 * Is a reservation fundamentally not possible? 305 */ 306 VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); 307 if (pindex < VM_RESERV_INDEX(object, pindex) || 308 pindex >= object->size) 309 return (NULL); 310 311 /* 312 * Look for an existing reservation. 313 */ 314 msucc = NULL; 315 mpred = object->root; 316 while (mpred != NULL) { 317 KASSERT(mpred->pindex != pindex, 318 ("vm_reserv_alloc_page: pindex already allocated")); 319 rv = vm_reserv_from_page(mpred); 320 if (rv->object == object && vm_reserv_has_pindex(rv, pindex)) { 321 m = &rv->pages[VM_RESERV_INDEX(object, pindex)]; 322 /* Handle vm_page_rename(m, new_object, ...). */ 323 if ((m->flags & (PG_CACHED | PG_FREE)) == 0) 324 return (NULL); 325 vm_reserv_populate(rv); 326 return (m); 327 } else if (mpred->pindex < pindex) { 328 if (msucc != NULL || 329 (msucc = TAILQ_NEXT(mpred, listq)) == NULL) 330 break; 331 KASSERT(msucc->pindex != pindex, 332 ("vm_reserv_alloc_page: pindex already allocated")); 333 rv = vm_reserv_from_page(msucc); 334 if (rv->object == object && 335 vm_reserv_has_pindex(rv, pindex)) { 336 m = &rv->pages[VM_RESERV_INDEX(object, pindex)]; 337 /* Handle vm_page_rename(m, new_object, ...). */ 338 if ((m->flags & (PG_CACHED | PG_FREE)) == 0) 339 return (NULL); 340 vm_reserv_populate(rv); 341 return (m); 342 } else if (pindex < msucc->pindex) 343 break; 344 } else if (msucc == NULL) { 345 msucc = mpred; 346 mpred = TAILQ_PREV(msucc, pglist, listq); 347 continue; 348 } 349 msucc = NULL; 350 mpred = object->root = vm_page_splay(pindex, object->root); 351 } 352 353 /* 354 * Determine the first index to the left that can be used. 355 */ 356 if (mpred == NULL) 357 leftcap = 0; 358 else if ((rv = vm_reserv_from_page(mpred))->object != object) 359 leftcap = mpred->pindex + 1; 360 else 361 leftcap = rv->pindex + VM_LEVEL_0_NPAGES; 362 363 /* 364 * Determine the first index to the right that cannot be used. 365 */ 366 if (msucc == NULL) 367 rightcap = pindex + VM_LEVEL_0_NPAGES; 368 else if ((rv = vm_reserv_from_page(msucc))->object != object) 369 rightcap = msucc->pindex; 370 else 371 rightcap = rv->pindex; 372 373 /* 374 * Determine if a reservation fits between the first index to 375 * the left that can be used and the first index to the right 376 * that cannot be used. 377 */ 378 first = pindex - VM_RESERV_INDEX(object, pindex); 379 if (first < leftcap || first + VM_LEVEL_0_NPAGES > rightcap) 380 return (NULL); 381 382 /* 383 * Would a new reservation extend past the end of the given object? 384 */ 385 if (object->size < first + VM_LEVEL_0_NPAGES) { 386 /* 387 * Don't allocate a new reservation if the object is a vnode or 388 * backed by another object that is a vnode. 389 */ 390 if (object->type == OBJT_VNODE || 391 (object->backing_object != NULL && 392 object->backing_object->type == OBJT_VNODE)) 393 return (NULL); 394 /* Speculate that the object may grow. */ 395 } 396 397 /* 398 * Allocate a new reservation. 399 */ 400 m = vm_phys_alloc_pages(VM_FREEPOOL_DEFAULT, VM_LEVEL_0_ORDER); 401 if (m != NULL) { 402 rv = vm_reserv_from_page(m); 403 KASSERT(rv->pages == m, 404 ("vm_reserv_alloc_page: reserv %p's pages is corrupted", 405 rv)); 406 KASSERT(rv->object == NULL, 407 ("vm_reserv_alloc_page: reserv %p isn't free", rv)); 408 LIST_INSERT_HEAD(&object->rvq, rv, objq); 409 rv->object = object; 410 rv->pindex = first; 411 KASSERT(rv->popcnt == 0, 412 ("vm_reserv_alloc_page: reserv %p's popcnt is corrupted", 413 rv)); 414 KASSERT(!rv->inpartpopq, 415 ("vm_reserv_alloc_page: reserv %p's inpartpopq is TRUE", 416 rv)); 417 vm_reserv_populate(rv); 418 m = &rv->pages[VM_RESERV_INDEX(object, pindex)]; 419 } 420 return (m); 421 } 422 423 /* 424 * Breaks all reservations belonging to the given object. 425 */ 426 void 427 vm_reserv_break_all(vm_object_t object) 428 { 429 vm_reserv_t rv; 430 int i; 431 432 mtx_lock(&vm_page_queue_free_mtx); 433 while ((rv = LIST_FIRST(&object->rvq)) != NULL) { 434 KASSERT(rv->object == object, 435 ("vm_reserv_break_all: reserv %p is corrupted", rv)); 436 if (rv->inpartpopq) { 437 TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); 438 rv->inpartpopq = FALSE; 439 } 440 LIST_REMOVE(rv, objq); 441 rv->object = NULL; 442 for (i = 0; i < VM_LEVEL_0_NPAGES; i++) { 443 if ((rv->pages[i].flags & (PG_CACHED | PG_FREE)) != 0) 444 vm_phys_free_pages(&rv->pages[i], 0); 445 else 446 rv->popcnt--; 447 } 448 KASSERT(rv->popcnt == 0, 449 ("vm_reserv_break_all: reserv %p's popcnt is corrupted", 450 rv)); 451 vm_reserv_broken++; 452 } 453 mtx_unlock(&vm_page_queue_free_mtx); 454 } 455 456 /* 457 * Frees the given page if it belongs to a reservation. Returns TRUE if the 458 * page is freed and FALSE otherwise. 459 * 460 * The free page queue lock must be held. 461 */ 462 boolean_t 463 vm_reserv_free_page(vm_page_t m) 464 { 465 vm_reserv_t rv; 466 467 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 468 rv = vm_reserv_from_page(m); 469 if (rv->object == NULL) 470 return (FALSE); 471 if ((m->flags & PG_CACHED) != 0 && m->pool != VM_FREEPOOL_CACHE) 472 vm_phys_set_pool(VM_FREEPOOL_CACHE, rv->pages, 473 VM_LEVEL_0_ORDER); 474 vm_reserv_depopulate(rv); 475 return (TRUE); 476 } 477 478 /* 479 * Initializes the reservation management system. Specifically, initializes 480 * the reservation array. 481 * 482 * Requires that vm_page_array and first_page are initialized! 483 */ 484 void 485 vm_reserv_init(void) 486 { 487 vm_paddr_t paddr; 488 int i; 489 490 /* 491 * Initialize the reservation array. Specifically, initialize the 492 * "pages" field for every element that has an underlying superpage. 493 */ 494 for (i = 0; phys_avail[i + 1] != 0; i += 2) { 495 paddr = roundup2(phys_avail[i], VM_LEVEL_0_SIZE); 496 while (paddr + VM_LEVEL_0_SIZE <= phys_avail[i + 1]) { 497 vm_reserv_array[paddr >> VM_LEVEL_0_SHIFT].pages = 498 PHYS_TO_VM_PAGE(paddr); 499 paddr += VM_LEVEL_0_SIZE; 500 } 501 } 502 } 503 504 /* 505 * Returns a reservation level if the given page belongs to a fully-populated 506 * reservation and -1 otherwise. 507 */ 508 int 509 vm_reserv_level_iffullpop(vm_page_t m) 510 { 511 vm_reserv_t rv; 512 513 rv = vm_reserv_from_page(m); 514 return (rv->popcnt == VM_LEVEL_0_NPAGES ? 0 : -1); 515 } 516 517 /* 518 * Prepare for the reactivation of a cached page. 519 * 520 * First, suppose that the given page "m" was allocated individually, i.e., not 521 * as part of a reservation, and cached. Then, suppose a reservation 522 * containing "m" is allocated by the same object. Although "m" and the 523 * reservation belong to the same object, "m"'s pindex may not match the 524 * reservation's. 525 * 526 * The free page queue must be locked. 527 */ 528 boolean_t 529 vm_reserv_reactivate_page(vm_page_t m) 530 { 531 vm_reserv_t rv; 532 int i, m_index; 533 534 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 535 rv = vm_reserv_from_page(m); 536 if (rv->object == NULL) 537 return (FALSE); 538 KASSERT((m->flags & PG_CACHED) != 0, 539 ("vm_reserv_uncache_page: page %p is not cached", m)); 540 if (m->object == rv->object && 541 m->pindex - rv->pindex == VM_RESERV_INDEX(m->object, m->pindex)) 542 vm_reserv_populate(rv); 543 else { 544 KASSERT(rv->inpartpopq, 545 ("vm_reserv_uncache_page: reserv %p's inpartpopq is FALSE", 546 rv)); 547 TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); 548 rv->inpartpopq = FALSE; 549 LIST_REMOVE(rv, objq); 550 rv->object = NULL; 551 /* Don't vm_phys_free_pages(m, 0). */ 552 m_index = m - rv->pages; 553 for (i = 0; i < m_index; i++) { 554 if ((rv->pages[i].flags & (PG_CACHED | PG_FREE)) != 0) 555 vm_phys_free_pages(&rv->pages[i], 0); 556 else 557 rv->popcnt--; 558 } 559 for (i++; i < VM_LEVEL_0_NPAGES; i++) { 560 if ((rv->pages[i].flags & (PG_CACHED | PG_FREE)) != 0) 561 vm_phys_free_pages(&rv->pages[i], 0); 562 else 563 rv->popcnt--; 564 } 565 KASSERT(rv->popcnt == 0, 566 ("vm_reserv_uncache_page: reserv %p's popcnt is corrupted", 567 rv)); 568 vm_reserv_broken++; 569 } 570 return (TRUE); 571 } 572 573 /* 574 * Breaks the given partially-populated reservation, releasing its cached and 575 * free pages to the physical memory allocator. 576 * 577 * The free page queue lock must be held. 578 */ 579 static void 580 vm_reserv_reclaim(vm_reserv_t rv) 581 { 582 int i; 583 584 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 585 KASSERT(rv->inpartpopq, 586 ("vm_reserv_reclaim: reserv %p's inpartpopq is corrupted", rv)); 587 TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); 588 rv->inpartpopq = FALSE; 589 KASSERT(rv->object != NULL, 590 ("vm_reserv_reclaim: reserv %p is free", rv)); 591 LIST_REMOVE(rv, objq); 592 rv->object = NULL; 593 for (i = 0; i < VM_LEVEL_0_NPAGES; i++) { 594 if ((rv->pages[i].flags & (PG_CACHED | PG_FREE)) != 0) 595 vm_phys_free_pages(&rv->pages[i], 0); 596 else 597 rv->popcnt--; 598 } 599 KASSERT(rv->popcnt == 0, 600 ("vm_reserv_reclaim: reserv %p's popcnt is corrupted", rv)); 601 vm_reserv_reclaimed++; 602 } 603 604 /* 605 * Breaks the reservation at the head of the partially-populated reservation 606 * queue, releasing its cached and free pages to the physical memory 607 * allocator. Returns TRUE if a reservation is broken and FALSE otherwise. 608 * 609 * The free page queue lock must be held. 610 */ 611 boolean_t 612 vm_reserv_reclaim_inactive(void) 613 { 614 vm_reserv_t rv; 615 616 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 617 if ((rv = TAILQ_FIRST(&vm_rvq_partpop)) != NULL) { 618 vm_reserv_reclaim(rv); 619 return (TRUE); 620 } 621 return (FALSE); 622 } 623 624 /* 625 * Searches the partially-populated reservation queue for the least recently 626 * active reservation with unused pages, i.e., cached or free, that satisfy the 627 * given request for contiguous physical memory. If a satisfactory reservation 628 * is found, it is broken. Returns TRUE if a reservation is broken and FALSE 629 * otherwise. 630 * 631 * The free page queue lock must be held. 632 */ 633 boolean_t 634 vm_reserv_reclaim_contig(vm_paddr_t size, vm_paddr_t low, vm_paddr_t high, 635 unsigned long alignment, unsigned long boundary) 636 { 637 vm_paddr_t pa, pa_length; 638 vm_reserv_t rv; 639 int i; 640 641 mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); 642 if (size > VM_LEVEL_0_SIZE - PAGE_SIZE) 643 return (FALSE); 644 TAILQ_FOREACH(rv, &vm_rvq_partpop, partpopq) { 645 pa = VM_PAGE_TO_PHYS(&rv->pages[VM_LEVEL_0_NPAGES - 1]); 646 if (pa + PAGE_SIZE - size < low) { 647 /* this entire reservation is too low; go to next */ 648 continue; 649 } 650 pa_length = 0; 651 for (i = 0; i < VM_LEVEL_0_NPAGES; i++) 652 if ((rv->pages[i].flags & (PG_CACHED | PG_FREE)) != 0) { 653 pa_length += PAGE_SIZE; 654 if (pa_length == PAGE_SIZE) { 655 pa = VM_PAGE_TO_PHYS(&rv->pages[i]); 656 if (pa + size > high) { 657 /* skip to next reservation */ 658 break; 659 } else if (pa < low || 660 (pa & (alignment - 1)) != 0 || 661 ((pa ^ (pa + size - 1)) & 662 ~(boundary - 1)) != 0) 663 pa_length = 0; 664 } 665 if (pa_length >= size) { 666 vm_reserv_reclaim(rv); 667 return (TRUE); 668 } 669 } else 670 pa_length = 0; 671 } 672 return (FALSE); 673 } 674 675 /* 676 * Transfers the reservation underlying the given page to a new object. 677 * 678 * The object must be locked. 679 */ 680 void 681 vm_reserv_rename(vm_page_t m, vm_object_t new_object, vm_object_t old_object, 682 vm_pindex_t old_object_offset) 683 { 684 vm_reserv_t rv; 685 686 VM_OBJECT_LOCK_ASSERT(new_object, MA_OWNED); 687 rv = vm_reserv_from_page(m); 688 if (rv->object == old_object) { 689 mtx_lock(&vm_page_queue_free_mtx); 690 if (rv->object == old_object) { 691 LIST_REMOVE(rv, objq); 692 LIST_INSERT_HEAD(&new_object->rvq, rv, objq); 693 rv->object = new_object; 694 rv->pindex -= old_object_offset; 695 } 696 mtx_unlock(&vm_page_queue_free_mtx); 697 } 698 } 699 700 /* 701 * Allocates the virtual and physical memory required by the reservation 702 * management system's data structures, in particular, the reservation array. 703 */ 704 vm_paddr_t 705 vm_reserv_startup(vm_offset_t *vaddr, vm_paddr_t end, vm_paddr_t high_water) 706 { 707 vm_paddr_t new_end; 708 size_t size; 709 710 /* 711 * Calculate the size (in bytes) of the reservation array. Round up 712 * from "high_water" because every small page is mapped to an element 713 * in the reservation array based on its physical address. Thus, the 714 * number of elements in the reservation array can be greater than the 715 * number of superpages. 716 */ 717 size = howmany(high_water, VM_LEVEL_0_SIZE) * sizeof(struct vm_reserv); 718 719 /* 720 * Allocate and map the physical memory for the reservation array. The 721 * next available virtual address is returned by reference. 722 */ 723 new_end = end - round_page(size); 724 vm_reserv_array = (void *)(uintptr_t)pmap_map(vaddr, new_end, end, 725 VM_PROT_READ | VM_PROT_WRITE); 726 bzero(vm_reserv_array, size); 727 728 /* 729 * Return the next available physical address. 730 */ 731 return (new_end); 732 } 733 734 #endif /* VM_NRESERVLEVEL > 0 */
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