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_radix.c
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1 /* 2 * Copyright (c) 2013 EMC Corp. 3 * Copyright (c) 2011 Jeffrey Roberson <jeff@freebsd.org> 4 * Copyright (c) 2008 Mayur Shardul <mayur.shardul@gmail.com> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 */ 29 30 /* 31 * Path-compressed radix trie implementation. 32 * The following code is not generalized into a general purpose library 33 * because there are way too many parameters embedded that should really 34 * be decided by the library consumers. At the same time, consumers 35 * of this code must achieve highest possible performance. 36 * 37 * The implementation takes into account the following rationale: 38 * - Size of the nodes should be as small as possible but still big enough 39 * to avoid a large maximum depth for the trie. This is a balance 40 * between the necessity to not wire too much physical memory for the nodes 41 * and the necessity to avoid too much cache pollution during the trie 42 * operations. 43 * - There is not a huge bias toward the number of lookup operations over 44 * the number of insert and remove operations. This basically implies 45 * that optimizations supposedly helping one operation but hurting the 46 * other might be carefully evaluated. 47 * - On average not many nodes are expected to be fully populated, hence 48 * level compression may just complicate things. 49 */ 50 51 #include <sys/cdefs.h> 52 __FBSDID("$FreeBSD$"); 53 54 #include "opt_ddb.h" 55 56 #include <sys/param.h> 57 #include <sys/systm.h> 58 #include <sys/kernel.h> 59 #include <sys/vmmeter.h> 60 61 #include <vm/uma.h> 62 #include <vm/vm.h> 63 #include <vm/vm_param.h> 64 #include <vm/vm_page.h> 65 #include <vm/vm_radix.h> 66 67 #ifdef DDB 68 #include <ddb/ddb.h> 69 #endif 70 71 /* 72 * These widths should allow the pointers to a node's children to fit within 73 * a single cache line. The extra levels from a narrow width should not be 74 * a problem thanks to path compression. 75 */ 76 #ifdef __LP64__ 77 #define VM_RADIX_WIDTH 4 78 #else 79 #define VM_RADIX_WIDTH 3 80 #endif 81 82 #define VM_RADIX_COUNT (1 << VM_RADIX_WIDTH) 83 #define VM_RADIX_MASK (VM_RADIX_COUNT - 1) 84 #define VM_RADIX_LIMIT \ 85 (howmany(sizeof(vm_pindex_t) * NBBY, VM_RADIX_WIDTH) - 1) 86 87 /* Flag bits stored in node pointers. */ 88 #define VM_RADIX_ISLEAF 0x1 89 #define VM_RADIX_FLAGS 0x1 90 #define VM_RADIX_PAD VM_RADIX_FLAGS 91 92 /* Returns one unit associated with specified level. */ 93 #define VM_RADIX_UNITLEVEL(lev) \ 94 ((vm_pindex_t)1 << ((lev) * VM_RADIX_WIDTH)) 95 96 struct vm_radix_node { 97 vm_pindex_t rn_owner; /* Owner of record. */ 98 uint16_t rn_count; /* Valid children. */ 99 uint16_t rn_clev; /* Current level. */ 100 void *rn_child[VM_RADIX_COUNT]; /* Child nodes. */ 101 }; 102 103 static uma_zone_t vm_radix_node_zone; 104 105 /* 106 * Allocate a radix node. 107 */ 108 static __inline struct vm_radix_node * 109 vm_radix_node_get(vm_pindex_t owner, uint16_t count, uint16_t clevel) 110 { 111 struct vm_radix_node *rnode; 112 113 rnode = uma_zalloc(vm_radix_node_zone, M_NOWAIT | M_ZERO); 114 if (rnode == NULL) 115 return (NULL); 116 rnode->rn_owner = owner; 117 rnode->rn_count = count; 118 rnode->rn_clev = clevel; 119 return (rnode); 120 } 121 122 /* 123 * Free radix node. 124 */ 125 static __inline void 126 vm_radix_node_put(struct vm_radix_node *rnode) 127 { 128 129 uma_zfree(vm_radix_node_zone, rnode); 130 } 131 132 /* 133 * Return the position in the array for a given level. 134 */ 135 static __inline int 136 vm_radix_slot(vm_pindex_t index, uint16_t level) 137 { 138 139 return ((index >> (level * VM_RADIX_WIDTH)) & VM_RADIX_MASK); 140 } 141 142 /* Trims the key after the specified level. */ 143 static __inline vm_pindex_t 144 vm_radix_trimkey(vm_pindex_t index, uint16_t level) 145 { 146 vm_pindex_t ret; 147 148 ret = index; 149 if (level > 0) { 150 ret >>= level * VM_RADIX_WIDTH; 151 ret <<= level * VM_RADIX_WIDTH; 152 } 153 return (ret); 154 } 155 156 /* 157 * Get the root node for a radix tree. 158 */ 159 static __inline struct vm_radix_node * 160 vm_radix_getroot(struct vm_radix *rtree) 161 { 162 163 return ((struct vm_radix_node *)rtree->rt_root); 164 } 165 166 /* 167 * Set the root node for a radix tree. 168 */ 169 static __inline void 170 vm_radix_setroot(struct vm_radix *rtree, struct vm_radix_node *rnode) 171 { 172 173 rtree->rt_root = (uintptr_t)rnode; 174 } 175 176 /* 177 * Returns TRUE if the specified radix node is a leaf and FALSE otherwise. 178 */ 179 static __inline boolean_t 180 vm_radix_isleaf(struct vm_radix_node *rnode) 181 { 182 183 return (((uintptr_t)rnode & VM_RADIX_ISLEAF) != 0); 184 } 185 186 /* 187 * Returns the associated page extracted from rnode. 188 */ 189 static __inline vm_page_t 190 vm_radix_topage(struct vm_radix_node *rnode) 191 { 192 193 return ((vm_page_t)((uintptr_t)rnode & ~VM_RADIX_FLAGS)); 194 } 195 196 /* 197 * Adds the page as a child of the provided node. 198 */ 199 static __inline void 200 vm_radix_addpage(struct vm_radix_node *rnode, vm_pindex_t index, uint16_t clev, 201 vm_page_t page) 202 { 203 int slot; 204 205 slot = vm_radix_slot(index, clev); 206 rnode->rn_child[slot] = (void *)((uintptr_t)page | VM_RADIX_ISLEAF); 207 } 208 209 /* 210 * Returns the slot where two keys differ. 211 * It cannot accept 2 equal keys. 212 */ 213 static __inline uint16_t 214 vm_radix_keydiff(vm_pindex_t index1, vm_pindex_t index2) 215 { 216 uint16_t clev; 217 218 KASSERT(index1 != index2, ("%s: passing the same key value %jx", 219 __func__, (uintmax_t)index1)); 220 221 index1 ^= index2; 222 for (clev = VM_RADIX_LIMIT;; clev--) 223 if (vm_radix_slot(index1, clev) != 0) 224 return (clev); 225 } 226 227 /* 228 * Returns TRUE if it can be determined that key does not belong to the 229 * specified rnode. Otherwise, returns FALSE. 230 */ 231 static __inline boolean_t 232 vm_radix_keybarr(struct vm_radix_node *rnode, vm_pindex_t idx) 233 { 234 235 if (rnode->rn_clev < VM_RADIX_LIMIT) { 236 idx = vm_radix_trimkey(idx, rnode->rn_clev + 1); 237 return (idx != rnode->rn_owner); 238 } 239 return (FALSE); 240 } 241 242 /* 243 * Internal helper for vm_radix_reclaim_allnodes(). 244 * This function is recursive. 245 */ 246 static void 247 vm_radix_reclaim_allnodes_int(struct vm_radix_node *rnode) 248 { 249 int slot; 250 251 KASSERT(rnode->rn_count <= VM_RADIX_COUNT, 252 ("vm_radix_reclaim_allnodes_int: bad count in rnode %p", rnode)); 253 for (slot = 0; rnode->rn_count != 0; slot++) { 254 if (rnode->rn_child[slot] == NULL) 255 continue; 256 if (!vm_radix_isleaf(rnode->rn_child[slot])) 257 vm_radix_reclaim_allnodes_int(rnode->rn_child[slot]); 258 rnode->rn_child[slot] = NULL; 259 rnode->rn_count--; 260 } 261 vm_radix_node_put(rnode); 262 } 263 264 #ifdef INVARIANTS 265 /* 266 * Radix node zone destructor. 267 */ 268 static void 269 vm_radix_node_zone_dtor(void *mem, int size __unused, void *arg __unused) 270 { 271 struct vm_radix_node *rnode; 272 int slot; 273 274 rnode = mem; 275 KASSERT(rnode->rn_count == 0, 276 ("vm_radix_node_put: rnode %p has %d children", rnode, 277 rnode->rn_count)); 278 for (slot = 0; slot < VM_RADIX_COUNT; slot++) 279 KASSERT(rnode->rn_child[slot] == NULL, 280 ("vm_radix_node_put: rnode %p has a child", rnode)); 281 } 282 #endif 283 284 #ifndef UMA_MD_SMALL_ALLOC 285 /* 286 * Reserve the KVA necessary to satisfy the node allocation. 287 * This is mandatory in architectures not supporting direct 288 * mapping as they will need otherwise to carve into the kernel maps for 289 * every node allocation, resulting into deadlocks for consumers already 290 * working with kernel maps. 291 */ 292 static void 293 vm_radix_reserve_kva(void *arg __unused) 294 { 295 296 /* 297 * Calculate the number of reserved nodes, discounting the pages that 298 * are needed to store them. 299 */ 300 if (!uma_zone_reserve_kva(vm_radix_node_zone, 301 ((vm_paddr_t)vm_cnt.v_page_count * PAGE_SIZE) / (PAGE_SIZE + 302 sizeof(struct vm_radix_node)))) 303 panic("%s: unable to reserve KVA", __func__); 304 } 305 SYSINIT(vm_radix_reserve_kva, SI_SUB_KMEM, SI_ORDER_THIRD, 306 vm_radix_reserve_kva, NULL); 307 #endif 308 309 /* 310 * Initialize the UMA slab zone. 311 */ 312 void 313 vm_radix_zinit(void) 314 { 315 316 vm_radix_node_zone = uma_zcreate("RADIX NODE", 317 sizeof(struct vm_radix_node), NULL, 318 #ifdef INVARIANTS 319 vm_radix_node_zone_dtor, 320 #else 321 NULL, 322 #endif 323 NULL, NULL, VM_RADIX_PAD, UMA_ZONE_VM); 324 } 325 326 /* 327 * Inserts the key-value pair into the trie. 328 * Panics if the key already exists. 329 */ 330 int 331 vm_radix_insert(struct vm_radix *rtree, vm_page_t page) 332 { 333 vm_pindex_t index, newind; 334 void **parentp; 335 struct vm_radix_node *rnode, *tmp; 336 vm_page_t m; 337 int slot; 338 uint16_t clev; 339 340 index = page->pindex; 341 342 /* 343 * The owner of record for root is not really important because it 344 * will never be used. 345 */ 346 rnode = vm_radix_getroot(rtree); 347 if (rnode == NULL) { 348 rtree->rt_root = (uintptr_t)page | VM_RADIX_ISLEAF; 349 return (0); 350 } 351 parentp = (void **)&rtree->rt_root; 352 for (;;) { 353 if (vm_radix_isleaf(rnode)) { 354 m = vm_radix_topage(rnode); 355 if (m->pindex == index) 356 panic("%s: key %jx is already present", 357 __func__, (uintmax_t)index); 358 clev = vm_radix_keydiff(m->pindex, index); 359 tmp = vm_radix_node_get(vm_radix_trimkey(index, 360 clev + 1), 2, clev); 361 if (tmp == NULL) 362 return (ENOMEM); 363 *parentp = tmp; 364 vm_radix_addpage(tmp, index, clev, page); 365 vm_radix_addpage(tmp, m->pindex, clev, m); 366 return (0); 367 } else if (vm_radix_keybarr(rnode, index)) 368 break; 369 slot = vm_radix_slot(index, rnode->rn_clev); 370 if (rnode->rn_child[slot] == NULL) { 371 rnode->rn_count++; 372 vm_radix_addpage(rnode, index, rnode->rn_clev, page); 373 return (0); 374 } 375 parentp = &rnode->rn_child[slot]; 376 rnode = rnode->rn_child[slot]; 377 } 378 379 /* 380 * A new node is needed because the right insertion level is reached. 381 * Setup the new intermediate node and add the 2 children: the 382 * new object and the older edge. 383 */ 384 newind = rnode->rn_owner; 385 clev = vm_radix_keydiff(newind, index); 386 tmp = vm_radix_node_get(vm_radix_trimkey(index, clev + 1), 2, clev); 387 if (tmp == NULL) 388 return (ENOMEM); 389 *parentp = tmp; 390 vm_radix_addpage(tmp, index, clev, page); 391 slot = vm_radix_slot(newind, clev); 392 tmp->rn_child[slot] = rnode; 393 return (0); 394 } 395 396 /* 397 * Returns TRUE if the specified radix tree contains a single leaf and FALSE 398 * otherwise. 399 */ 400 boolean_t 401 vm_radix_is_singleton(struct vm_radix *rtree) 402 { 403 struct vm_radix_node *rnode; 404 405 rnode = vm_radix_getroot(rtree); 406 if (rnode == NULL) 407 return (FALSE); 408 return (vm_radix_isleaf(rnode)); 409 } 410 411 /* 412 * Returns the value stored at the index. If the index is not present, 413 * NULL is returned. 414 */ 415 vm_page_t 416 vm_radix_lookup(struct vm_radix *rtree, vm_pindex_t index) 417 { 418 struct vm_radix_node *rnode; 419 vm_page_t m; 420 int slot; 421 422 rnode = vm_radix_getroot(rtree); 423 while (rnode != NULL) { 424 if (vm_radix_isleaf(rnode)) { 425 m = vm_radix_topage(rnode); 426 if (m->pindex == index) 427 return (m); 428 else 429 break; 430 } else if (vm_radix_keybarr(rnode, index)) 431 break; 432 slot = vm_radix_slot(index, rnode->rn_clev); 433 rnode = rnode->rn_child[slot]; 434 } 435 return (NULL); 436 } 437 438 /* 439 * Look up the nearest entry at a position bigger than or equal to index. 440 */ 441 vm_page_t 442 vm_radix_lookup_ge(struct vm_radix *rtree, vm_pindex_t index) 443 { 444 struct vm_radix_node *stack[VM_RADIX_LIMIT]; 445 vm_pindex_t inc; 446 vm_page_t m; 447 struct vm_radix_node *child, *rnode; 448 #ifdef INVARIANTS 449 int loops = 0; 450 #endif 451 int slot, tos; 452 453 rnode = vm_radix_getroot(rtree); 454 if (rnode == NULL) 455 return (NULL); 456 else if (vm_radix_isleaf(rnode)) { 457 m = vm_radix_topage(rnode); 458 if (m->pindex >= index) 459 return (m); 460 else 461 return (NULL); 462 } 463 tos = 0; 464 for (;;) { 465 /* 466 * If the keys differ before the current bisection node, 467 * then the search key might rollback to the earliest 468 * available bisection node or to the smallest key 469 * in the current node (if the owner is bigger than the 470 * search key). 471 */ 472 if (vm_radix_keybarr(rnode, index)) { 473 if (index > rnode->rn_owner) { 474 ascend: 475 KASSERT(++loops < 1000, 476 ("vm_radix_lookup_ge: too many loops")); 477 478 /* 479 * Pop nodes from the stack until either the 480 * stack is empty or a node that could have a 481 * matching descendant is found. 482 */ 483 do { 484 if (tos == 0) 485 return (NULL); 486 rnode = stack[--tos]; 487 } while (vm_radix_slot(index, 488 rnode->rn_clev) == (VM_RADIX_COUNT - 1)); 489 490 /* 491 * The following computation cannot overflow 492 * because index's slot at the current level 493 * is less than VM_RADIX_COUNT - 1. 494 */ 495 index = vm_radix_trimkey(index, 496 rnode->rn_clev); 497 index += VM_RADIX_UNITLEVEL(rnode->rn_clev); 498 } else 499 index = rnode->rn_owner; 500 KASSERT(!vm_radix_keybarr(rnode, index), 501 ("vm_radix_lookup_ge: keybarr failed")); 502 } 503 slot = vm_radix_slot(index, rnode->rn_clev); 504 child = rnode->rn_child[slot]; 505 if (vm_radix_isleaf(child)) { 506 m = vm_radix_topage(child); 507 if (m->pindex >= index) 508 return (m); 509 } else if (child != NULL) 510 goto descend; 511 512 /* 513 * Look for an available edge or page within the current 514 * bisection node. 515 */ 516 if (slot < (VM_RADIX_COUNT - 1)) { 517 inc = VM_RADIX_UNITLEVEL(rnode->rn_clev); 518 index = vm_radix_trimkey(index, rnode->rn_clev); 519 do { 520 index += inc; 521 slot++; 522 child = rnode->rn_child[slot]; 523 if (vm_radix_isleaf(child)) { 524 m = vm_radix_topage(child); 525 if (m->pindex >= index) 526 return (m); 527 } else if (child != NULL) 528 goto descend; 529 } while (slot < (VM_RADIX_COUNT - 1)); 530 } 531 KASSERT(child == NULL || vm_radix_isleaf(child), 532 ("vm_radix_lookup_ge: child is radix node")); 533 534 /* 535 * If a page or edge bigger than the search slot is not found 536 * in the current node, ascend to the next higher-level node. 537 */ 538 goto ascend; 539 descend: 540 KASSERT(rnode->rn_clev > 0, 541 ("vm_radix_lookup_ge: pushing leaf's parent")); 542 KASSERT(tos < VM_RADIX_LIMIT, 543 ("vm_radix_lookup_ge: stack overflow")); 544 stack[tos++] = rnode; 545 rnode = child; 546 } 547 } 548 549 /* 550 * Look up the nearest entry at a position less than or equal to index. 551 */ 552 vm_page_t 553 vm_radix_lookup_le(struct vm_radix *rtree, vm_pindex_t index) 554 { 555 struct vm_radix_node *stack[VM_RADIX_LIMIT]; 556 vm_pindex_t inc; 557 vm_page_t m; 558 struct vm_radix_node *child, *rnode; 559 #ifdef INVARIANTS 560 int loops = 0; 561 #endif 562 int slot, tos; 563 564 rnode = vm_radix_getroot(rtree); 565 if (rnode == NULL) 566 return (NULL); 567 else if (vm_radix_isleaf(rnode)) { 568 m = vm_radix_topage(rnode); 569 if (m->pindex <= index) 570 return (m); 571 else 572 return (NULL); 573 } 574 tos = 0; 575 for (;;) { 576 /* 577 * If the keys differ before the current bisection node, 578 * then the search key might rollback to the earliest 579 * available bisection node or to the largest key 580 * in the current node (if the owner is smaller than the 581 * search key). 582 */ 583 if (vm_radix_keybarr(rnode, index)) { 584 if (index > rnode->rn_owner) { 585 index = rnode->rn_owner + VM_RADIX_COUNT * 586 VM_RADIX_UNITLEVEL(rnode->rn_clev); 587 } else { 588 ascend: 589 KASSERT(++loops < 1000, 590 ("vm_radix_lookup_le: too many loops")); 591 592 /* 593 * Pop nodes from the stack until either the 594 * stack is empty or a node that could have a 595 * matching descendant is found. 596 */ 597 do { 598 if (tos == 0) 599 return (NULL); 600 rnode = stack[--tos]; 601 } while (vm_radix_slot(index, 602 rnode->rn_clev) == 0); 603 604 /* 605 * The following computation cannot overflow 606 * because index's slot at the current level 607 * is greater than 0. 608 */ 609 index = vm_radix_trimkey(index, 610 rnode->rn_clev); 611 } 612 index--; 613 KASSERT(!vm_radix_keybarr(rnode, index), 614 ("vm_radix_lookup_le: keybarr failed")); 615 } 616 slot = vm_radix_slot(index, rnode->rn_clev); 617 child = rnode->rn_child[slot]; 618 if (vm_radix_isleaf(child)) { 619 m = vm_radix_topage(child); 620 if (m->pindex <= index) 621 return (m); 622 } else if (child != NULL) 623 goto descend; 624 625 /* 626 * Look for an available edge or page within the current 627 * bisection node. 628 */ 629 if (slot > 0) { 630 inc = VM_RADIX_UNITLEVEL(rnode->rn_clev); 631 index |= inc - 1; 632 do { 633 index -= inc; 634 slot--; 635 child = rnode->rn_child[slot]; 636 if (vm_radix_isleaf(child)) { 637 m = vm_radix_topage(child); 638 if (m->pindex <= index) 639 return (m); 640 } else if (child != NULL) 641 goto descend; 642 } while (slot > 0); 643 } 644 KASSERT(child == NULL || vm_radix_isleaf(child), 645 ("vm_radix_lookup_le: child is radix node")); 646 647 /* 648 * If a page or edge smaller than the search slot is not found 649 * in the current node, ascend to the next higher-level node. 650 */ 651 goto ascend; 652 descend: 653 KASSERT(rnode->rn_clev > 0, 654 ("vm_radix_lookup_le: pushing leaf's parent")); 655 KASSERT(tos < VM_RADIX_LIMIT, 656 ("vm_radix_lookup_le: stack overflow")); 657 stack[tos++] = rnode; 658 rnode = child; 659 } 660 } 661 662 /* 663 * Remove the specified index from the trie, and return the value stored at 664 * that index. If the index is not present, return NULL. 665 */ 666 vm_page_t 667 vm_radix_remove(struct vm_radix *rtree, vm_pindex_t index) 668 { 669 struct vm_radix_node *rnode, *parent; 670 vm_page_t m; 671 int i, slot; 672 673 rnode = vm_radix_getroot(rtree); 674 if (vm_radix_isleaf(rnode)) { 675 m = vm_radix_topage(rnode); 676 if (m->pindex != index) 677 return (NULL); 678 vm_radix_setroot(rtree, NULL); 679 return (m); 680 } 681 parent = NULL; 682 for (;;) { 683 if (rnode == NULL) 684 return (NULL); 685 slot = vm_radix_slot(index, rnode->rn_clev); 686 if (vm_radix_isleaf(rnode->rn_child[slot])) { 687 m = vm_radix_topage(rnode->rn_child[slot]); 688 if (m->pindex != index) 689 return (NULL); 690 rnode->rn_child[slot] = NULL; 691 rnode->rn_count--; 692 if (rnode->rn_count > 1) 693 return (m); 694 for (i = 0; i < VM_RADIX_COUNT; i++) 695 if (rnode->rn_child[i] != NULL) 696 break; 697 KASSERT(i != VM_RADIX_COUNT, 698 ("%s: invalid node configuration", __func__)); 699 if (parent == NULL) 700 vm_radix_setroot(rtree, rnode->rn_child[i]); 701 else { 702 slot = vm_radix_slot(index, parent->rn_clev); 703 KASSERT(parent->rn_child[slot] == rnode, 704 ("%s: invalid child value", __func__)); 705 parent->rn_child[slot] = rnode->rn_child[i]; 706 } 707 rnode->rn_count--; 708 rnode->rn_child[i] = NULL; 709 vm_radix_node_put(rnode); 710 return (m); 711 } 712 parent = rnode; 713 rnode = rnode->rn_child[slot]; 714 } 715 } 716 717 /* 718 * Remove and free all the nodes from the radix tree. 719 * This function is recursive but there is a tight control on it as the 720 * maximum depth of the tree is fixed. 721 */ 722 void 723 vm_radix_reclaim_allnodes(struct vm_radix *rtree) 724 { 725 struct vm_radix_node *root; 726 727 root = vm_radix_getroot(rtree); 728 if (root == NULL) 729 return; 730 vm_radix_setroot(rtree, NULL); 731 if (!vm_radix_isleaf(root)) 732 vm_radix_reclaim_allnodes_int(root); 733 } 734 735 /* 736 * Replace an existing page in the trie with another one. 737 * Panics if there is not an old page in the trie at the new page's index. 738 */ 739 vm_page_t 740 vm_radix_replace(struct vm_radix *rtree, vm_page_t newpage) 741 { 742 struct vm_radix_node *rnode; 743 vm_page_t m; 744 vm_pindex_t index; 745 int slot; 746 747 index = newpage->pindex; 748 rnode = vm_radix_getroot(rtree); 749 if (rnode == NULL) 750 panic("%s: replacing page on an empty trie", __func__); 751 if (vm_radix_isleaf(rnode)) { 752 m = vm_radix_topage(rnode); 753 if (m->pindex != index) 754 panic("%s: original replacing root key not found", 755 __func__); 756 rtree->rt_root = (uintptr_t)newpage | VM_RADIX_ISLEAF; 757 return (m); 758 } 759 for (;;) { 760 slot = vm_radix_slot(index, rnode->rn_clev); 761 if (vm_radix_isleaf(rnode->rn_child[slot])) { 762 m = vm_radix_topage(rnode->rn_child[slot]); 763 if (m->pindex == index) { 764 rnode->rn_child[slot] = 765 (void *)((uintptr_t)newpage | 766 VM_RADIX_ISLEAF); 767 return (m); 768 } else 769 break; 770 } else if (rnode->rn_child[slot] == NULL || 771 vm_radix_keybarr(rnode->rn_child[slot], index)) 772 break; 773 rnode = rnode->rn_child[slot]; 774 } 775 panic("%s: original replacing page not found", __func__); 776 } 777 778 void 779 vm_radix_wait(void) 780 { 781 uma_zwait(vm_radix_node_zone); 782 } 783 784 #ifdef DDB 785 /* 786 * Show details about the given radix node. 787 */ 788 DB_SHOW_COMMAND(radixnode, db_show_radixnode) 789 { 790 struct vm_radix_node *rnode; 791 int i; 792 793 if (!have_addr) 794 return; 795 rnode = (struct vm_radix_node *)addr; 796 db_printf("radixnode %p, owner %jx, children count %u, level %u:\n", 797 (void *)rnode, (uintmax_t)rnode->rn_owner, rnode->rn_count, 798 rnode->rn_clev); 799 for (i = 0; i < VM_RADIX_COUNT; i++) 800 if (rnode->rn_child[i] != NULL) 801 db_printf("slot: %d, val: %p, page: %p, clev: %d\n", 802 i, (void *)rnode->rn_child[i], 803 vm_radix_isleaf(rnode->rn_child[i]) ? 804 vm_radix_topage(rnode->rn_child[i]) : NULL, 805 rnode->rn_clev); 806 } 807 #endif /* DDB */
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