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. Pre-allocation should ensure that the request 107 * will always be satisfied. 108 */ 109 static __inline struct vm_radix_node * 110 vm_radix_node_get(vm_pindex_t owner, uint16_t count, uint16_t clevel) 111 { 112 struct vm_radix_node *rnode; 113 114 rnode = uma_zalloc(vm_radix_node_zone, M_NOWAIT); 115 116 /* 117 * The required number of nodes should already be pre-allocated 118 * by vm_radix_prealloc(). However, UMA can hold a few nodes 119 * in per-CPU buckets, which will not be accessible by the 120 * current CPU. Thus, the allocation could return NULL when 121 * the pre-allocated pool is close to exhaustion. Anyway, 122 * in practice this should never occur because a new node 123 * is not always required for insert. Thus, the pre-allocated 124 * pool should have some extra pages that prevent this from 125 * becoming a problem. 126 */ 127 if (rnode == NULL) 128 panic("%s: uma_zalloc() returned NULL for a new node", 129 __func__); 130 rnode->rn_owner = owner; 131 rnode->rn_count = count; 132 rnode->rn_clev = clevel; 133 return (rnode); 134 } 135 136 /* 137 * Free radix node. 138 */ 139 static __inline void 140 vm_radix_node_put(struct vm_radix_node *rnode) 141 { 142 143 uma_zfree(vm_radix_node_zone, rnode); 144 } 145 146 /* 147 * Return the position in the array for a given level. 148 */ 149 static __inline int 150 vm_radix_slot(vm_pindex_t index, uint16_t level) 151 { 152 153 return ((index >> (level * VM_RADIX_WIDTH)) & VM_RADIX_MASK); 154 } 155 156 /* Trims the key after the specified level. */ 157 static __inline vm_pindex_t 158 vm_radix_trimkey(vm_pindex_t index, uint16_t level) 159 { 160 vm_pindex_t ret; 161 162 ret = index; 163 if (level > 0) { 164 ret >>= level * VM_RADIX_WIDTH; 165 ret <<= level * VM_RADIX_WIDTH; 166 } 167 return (ret); 168 } 169 170 /* 171 * Get the root node for a radix tree. 172 */ 173 static __inline struct vm_radix_node * 174 vm_radix_getroot(struct vm_radix *rtree) 175 { 176 177 return ((struct vm_radix_node *)rtree->rt_root); 178 } 179 180 /* 181 * Set the root node for a radix tree. 182 */ 183 static __inline void 184 vm_radix_setroot(struct vm_radix *rtree, struct vm_radix_node *rnode) 185 { 186 187 rtree->rt_root = (uintptr_t)rnode; 188 } 189 190 /* 191 * Returns TRUE if the specified radix node is a leaf and FALSE otherwise. 192 */ 193 static __inline boolean_t 194 vm_radix_isleaf(struct vm_radix_node *rnode) 195 { 196 197 return (((uintptr_t)rnode & VM_RADIX_ISLEAF) != 0); 198 } 199 200 /* 201 * Returns the associated page extracted from rnode. 202 */ 203 static __inline vm_page_t 204 vm_radix_topage(struct vm_radix_node *rnode) 205 { 206 207 return ((vm_page_t)((uintptr_t)rnode & ~VM_RADIX_FLAGS)); 208 } 209 210 /* 211 * Adds the page as a child of the provided node. 212 */ 213 static __inline void 214 vm_radix_addpage(struct vm_radix_node *rnode, vm_pindex_t index, uint16_t clev, 215 vm_page_t page) 216 { 217 int slot; 218 219 slot = vm_radix_slot(index, clev); 220 rnode->rn_child[slot] = (void *)((uintptr_t)page | VM_RADIX_ISLEAF); 221 } 222 223 /* 224 * Returns the slot where two keys differ. 225 * It cannot accept 2 equal keys. 226 */ 227 static __inline uint16_t 228 vm_radix_keydiff(vm_pindex_t index1, vm_pindex_t index2) 229 { 230 uint16_t clev; 231 232 KASSERT(index1 != index2, ("%s: passing the same key value %jx", 233 __func__, (uintmax_t)index1)); 234 235 index1 ^= index2; 236 for (clev = VM_RADIX_LIMIT;; clev--) 237 if (vm_radix_slot(index1, clev) != 0) 238 return (clev); 239 } 240 241 /* 242 * Returns TRUE if it can be determined that key does not belong to the 243 * specified rnode. Otherwise, returns FALSE. 244 */ 245 static __inline boolean_t 246 vm_radix_keybarr(struct vm_radix_node *rnode, vm_pindex_t idx) 247 { 248 249 if (rnode->rn_clev < VM_RADIX_LIMIT) { 250 idx = vm_radix_trimkey(idx, rnode->rn_clev + 1); 251 return (idx != rnode->rn_owner); 252 } 253 return (FALSE); 254 } 255 256 /* 257 * Internal helper for vm_radix_reclaim_allnodes(). 258 * This function is recursive. 259 */ 260 static void 261 vm_radix_reclaim_allnodes_int(struct vm_radix_node *rnode) 262 { 263 int slot; 264 265 KASSERT(rnode->rn_count <= VM_RADIX_COUNT, 266 ("vm_radix_reclaim_allnodes_int: bad count in rnode %p", rnode)); 267 for (slot = 0; rnode->rn_count != 0; slot++) { 268 if (rnode->rn_child[slot] == NULL) 269 continue; 270 if (!vm_radix_isleaf(rnode->rn_child[slot])) 271 vm_radix_reclaim_allnodes_int(rnode->rn_child[slot]); 272 rnode->rn_child[slot] = NULL; 273 rnode->rn_count--; 274 } 275 vm_radix_node_put(rnode); 276 } 277 278 #ifdef INVARIANTS 279 /* 280 * Radix node zone destructor. 281 */ 282 static void 283 vm_radix_node_zone_dtor(void *mem, int size __unused, void *arg __unused) 284 { 285 struct vm_radix_node *rnode; 286 int slot; 287 288 rnode = mem; 289 KASSERT(rnode->rn_count == 0, 290 ("vm_radix_node_put: rnode %p has %d children", rnode, 291 rnode->rn_count)); 292 for (slot = 0; slot < VM_RADIX_COUNT; slot++) 293 KASSERT(rnode->rn_child[slot] == NULL, 294 ("vm_radix_node_put: rnode %p has a child", rnode)); 295 } 296 #endif 297 298 /* 299 * Radix node zone initializer. 300 */ 301 static int 302 vm_radix_node_zone_init(void *mem, int size __unused, int flags __unused) 303 { 304 struct vm_radix_node *rnode; 305 306 rnode = mem; 307 memset(rnode->rn_child, 0, sizeof(rnode->rn_child)); 308 return (0); 309 } 310 311 /* 312 * Pre-allocate intermediate nodes from the UMA slab zone. 313 */ 314 static void 315 vm_radix_prealloc(void *arg __unused) 316 { 317 int nodes; 318 319 /* 320 * Calculate the number of reserved nodes, discounting the pages that 321 * are needed to store them. 322 */ 323 nodes = ((vm_paddr_t)cnt.v_page_count * PAGE_SIZE) / (PAGE_SIZE + 324 sizeof(struct vm_radix_node)); 325 if (!uma_zone_reserve_kva(vm_radix_node_zone, nodes)) 326 panic("%s: unable to create new zone", __func__); 327 uma_prealloc(vm_radix_node_zone, nodes); 328 } 329 SYSINIT(vm_radix_prealloc, SI_SUB_KMEM, SI_ORDER_SECOND, vm_radix_prealloc, 330 NULL); 331 332 /* 333 * Initialize the UMA slab zone. 334 * Until vm_radix_prealloc() is called, the zone will be served by the 335 * UMA boot-time pre-allocated pool of pages. 336 */ 337 void 338 vm_radix_init(void) 339 { 340 341 vm_radix_node_zone = uma_zcreate("RADIX NODE", 342 sizeof(struct vm_radix_node), NULL, 343 #ifdef INVARIANTS 344 vm_radix_node_zone_dtor, 345 #else 346 NULL, 347 #endif 348 vm_radix_node_zone_init, NULL, VM_RADIX_PAD, UMA_ZONE_VM | 349 UMA_ZONE_NOFREE); 350 } 351 352 /* 353 * Inserts the key-value pair into the trie. 354 * Panics if the key already exists. 355 */ 356 void 357 vm_radix_insert(struct vm_radix *rtree, vm_page_t page) 358 { 359 vm_pindex_t index, newind; 360 void **parentp; 361 struct vm_radix_node *rnode, *tmp; 362 vm_page_t m; 363 int slot; 364 uint16_t clev; 365 366 index = page->pindex; 367 368 /* 369 * The owner of record for root is not really important because it 370 * will never be used. 371 */ 372 rnode = vm_radix_getroot(rtree); 373 if (rnode == NULL) { 374 rtree->rt_root = (uintptr_t)page | VM_RADIX_ISLEAF; 375 return; 376 } 377 parentp = (void **)&rtree->rt_root; 378 for (;;) { 379 if (vm_radix_isleaf(rnode)) { 380 m = vm_radix_topage(rnode); 381 if (m->pindex == index) 382 panic("%s: key %jx is already present", 383 __func__, (uintmax_t)index); 384 clev = vm_radix_keydiff(m->pindex, index); 385 tmp = vm_radix_node_get(vm_radix_trimkey(index, 386 clev + 1), 2, clev); 387 *parentp = tmp; 388 vm_radix_addpage(tmp, index, clev, page); 389 vm_radix_addpage(tmp, m->pindex, clev, m); 390 return; 391 } else if (vm_radix_keybarr(rnode, index)) 392 break; 393 slot = vm_radix_slot(index, rnode->rn_clev); 394 if (rnode->rn_child[slot] == NULL) { 395 rnode->rn_count++; 396 vm_radix_addpage(rnode, index, rnode->rn_clev, page); 397 return; 398 } 399 parentp = &rnode->rn_child[slot]; 400 rnode = rnode->rn_child[slot]; 401 } 402 403 /* 404 * A new node is needed because the right insertion level is reached. 405 * Setup the new intermediate node and add the 2 children: the 406 * new object and the older edge. 407 */ 408 newind = rnode->rn_owner; 409 clev = vm_radix_keydiff(newind, index); 410 tmp = vm_radix_node_get(vm_radix_trimkey(index, clev + 1), 2, 411 clev); 412 *parentp = tmp; 413 vm_radix_addpage(tmp, index, clev, page); 414 slot = vm_radix_slot(newind, clev); 415 tmp->rn_child[slot] = rnode; 416 } 417 418 /* 419 * Returns the value stored at the index. If the index is not present, 420 * NULL is returned. 421 */ 422 vm_page_t 423 vm_radix_lookup(struct vm_radix *rtree, vm_pindex_t index) 424 { 425 struct vm_radix_node *rnode; 426 vm_page_t m; 427 int slot; 428 429 rnode = vm_radix_getroot(rtree); 430 while (rnode != NULL) { 431 if (vm_radix_isleaf(rnode)) { 432 m = vm_radix_topage(rnode); 433 if (m->pindex == index) 434 return (m); 435 else 436 break; 437 } else if (vm_radix_keybarr(rnode, index)) 438 break; 439 slot = vm_radix_slot(index, rnode->rn_clev); 440 rnode = rnode->rn_child[slot]; 441 } 442 return (NULL); 443 } 444 445 /* 446 * Look up the nearest entry at a position bigger than or equal to index. 447 */ 448 vm_page_t 449 vm_radix_lookup_ge(struct vm_radix *rtree, vm_pindex_t index) 450 { 451 struct vm_radix_node *stack[VM_RADIX_LIMIT]; 452 vm_pindex_t inc; 453 vm_page_t m; 454 struct vm_radix_node *child, *rnode; 455 #ifdef INVARIANTS 456 int loops = 0; 457 #endif 458 int slot, tos; 459 460 rnode = vm_radix_getroot(rtree); 461 if (rnode == NULL) 462 return (NULL); 463 else if (vm_radix_isleaf(rnode)) { 464 m = vm_radix_topage(rnode); 465 if (m->pindex >= index) 466 return (m); 467 else 468 return (NULL); 469 } 470 tos = 0; 471 for (;;) { 472 /* 473 * If the keys differ before the current bisection node, 474 * then the search key might rollback to the earliest 475 * available bisection node or to the smallest key 476 * in the current node (if the owner is bigger than the 477 * search key). 478 */ 479 if (vm_radix_keybarr(rnode, index)) { 480 if (index > rnode->rn_owner) { 481 ascend: 482 KASSERT(++loops < 1000, 483 ("vm_radix_lookup_ge: too many loops")); 484 485 /* 486 * Pop nodes from the stack until either the 487 * stack is empty or a node that could have a 488 * matching descendant is found. 489 */ 490 do { 491 if (tos == 0) 492 return (NULL); 493 rnode = stack[--tos]; 494 } while (vm_radix_slot(index, 495 rnode->rn_clev) == (VM_RADIX_COUNT - 1)); 496 497 /* 498 * The following computation cannot overflow 499 * because index's slot at the current level 500 * is less than VM_RADIX_COUNT - 1. 501 */ 502 index = vm_radix_trimkey(index, 503 rnode->rn_clev); 504 index += VM_RADIX_UNITLEVEL(rnode->rn_clev); 505 } else 506 index = rnode->rn_owner; 507 KASSERT(!vm_radix_keybarr(rnode, index), 508 ("vm_radix_lookup_ge: keybarr failed")); 509 } 510 slot = vm_radix_slot(index, rnode->rn_clev); 511 child = rnode->rn_child[slot]; 512 if (vm_radix_isleaf(child)) { 513 m = vm_radix_topage(child); 514 if (m->pindex >= index) 515 return (m); 516 } else if (child != NULL) 517 goto descend; 518 519 /* 520 * Look for an available edge or page within the current 521 * bisection node. 522 */ 523 if (slot < (VM_RADIX_COUNT - 1)) { 524 inc = VM_RADIX_UNITLEVEL(rnode->rn_clev); 525 index = vm_radix_trimkey(index, rnode->rn_clev); 526 do { 527 index += inc; 528 slot++; 529 child = rnode->rn_child[slot]; 530 if (vm_radix_isleaf(child)) { 531 m = vm_radix_topage(child); 532 if (m->pindex >= index) 533 return (m); 534 } else if (child != NULL) 535 goto descend; 536 } while (slot < (VM_RADIX_COUNT - 1)); 537 } 538 KASSERT(child == NULL || vm_radix_isleaf(child), 539 ("vm_radix_lookup_ge: child is radix node")); 540 541 /* 542 * If a page or edge bigger than the search slot is not found 543 * in the current node, ascend to the next higher-level node. 544 */ 545 goto ascend; 546 descend: 547 KASSERT(rnode->rn_clev > 0, 548 ("vm_radix_lookup_ge: pushing leaf's parent")); 549 KASSERT(tos < VM_RADIX_LIMIT, 550 ("vm_radix_lookup_ge: stack overflow")); 551 stack[tos++] = rnode; 552 rnode = child; 553 } 554 } 555 556 /* 557 * Look up the nearest entry at a position less than or equal to index. 558 */ 559 vm_page_t 560 vm_radix_lookup_le(struct vm_radix *rtree, vm_pindex_t index) 561 { 562 struct vm_radix_node *stack[VM_RADIX_LIMIT]; 563 vm_pindex_t inc; 564 vm_page_t m; 565 struct vm_radix_node *child, *rnode; 566 #ifdef INVARIANTS 567 int loops = 0; 568 #endif 569 int slot, tos; 570 571 rnode = vm_radix_getroot(rtree); 572 if (rnode == NULL) 573 return (NULL); 574 else if (vm_radix_isleaf(rnode)) { 575 m = vm_radix_topage(rnode); 576 if (m->pindex <= index) 577 return (m); 578 else 579 return (NULL); 580 } 581 tos = 0; 582 for (;;) { 583 /* 584 * If the keys differ before the current bisection node, 585 * then the search key might rollback to the earliest 586 * available bisection node or to the largest key 587 * in the current node (if the owner is smaller than the 588 * search key). 589 */ 590 if (vm_radix_keybarr(rnode, index)) { 591 if (index > rnode->rn_owner) { 592 index = rnode->rn_owner + VM_RADIX_COUNT * 593 VM_RADIX_UNITLEVEL(rnode->rn_clev); 594 } else { 595 ascend: 596 KASSERT(++loops < 1000, 597 ("vm_radix_lookup_le: too many loops")); 598 599 /* 600 * Pop nodes from the stack until either the 601 * stack is empty or a node that could have a 602 * matching descendant is found. 603 */ 604 do { 605 if (tos == 0) 606 return (NULL); 607 rnode = stack[--tos]; 608 } while (vm_radix_slot(index, 609 rnode->rn_clev) == 0); 610 611 /* 612 * The following computation cannot overflow 613 * because index's slot at the current level 614 * is greater than 0. 615 */ 616 index = vm_radix_trimkey(index, 617 rnode->rn_clev); 618 } 619 index--; 620 KASSERT(!vm_radix_keybarr(rnode, index), 621 ("vm_radix_lookup_le: keybarr failed")); 622 } 623 slot = vm_radix_slot(index, rnode->rn_clev); 624 child = rnode->rn_child[slot]; 625 if (vm_radix_isleaf(child)) { 626 m = vm_radix_topage(child); 627 if (m->pindex <= index) 628 return (m); 629 } else if (child != NULL) 630 goto descend; 631 632 /* 633 * Look for an available edge or page within the current 634 * bisection node. 635 */ 636 if (slot > 0) { 637 inc = VM_RADIX_UNITLEVEL(rnode->rn_clev); 638 index |= inc - 1; 639 do { 640 index -= inc; 641 slot--; 642 child = rnode->rn_child[slot]; 643 if (vm_radix_isleaf(child)) { 644 m = vm_radix_topage(child); 645 if (m->pindex <= index) 646 return (m); 647 } else if (child != NULL) 648 goto descend; 649 } while (slot > 0); 650 } 651 KASSERT(child == NULL || vm_radix_isleaf(child), 652 ("vm_radix_lookup_le: child is radix node")); 653 654 /* 655 * If a page or edge smaller than the search slot is not found 656 * in the current node, ascend to the next higher-level node. 657 */ 658 goto ascend; 659 descend: 660 KASSERT(rnode->rn_clev > 0, 661 ("vm_radix_lookup_le: pushing leaf's parent")); 662 KASSERT(tos < VM_RADIX_LIMIT, 663 ("vm_radix_lookup_le: stack overflow")); 664 stack[tos++] = rnode; 665 rnode = child; 666 } 667 } 668 669 /* 670 * Remove the specified index from the tree. 671 * Panics if the key is not present. 672 */ 673 void 674 vm_radix_remove(struct vm_radix *rtree, vm_pindex_t index) 675 { 676 struct vm_radix_node *rnode, *parent; 677 vm_page_t m; 678 int i, slot; 679 680 rnode = vm_radix_getroot(rtree); 681 if (vm_radix_isleaf(rnode)) { 682 m = vm_radix_topage(rnode); 683 if (m->pindex != index) 684 panic("%s: invalid key found", __func__); 685 vm_radix_setroot(rtree, NULL); 686 return; 687 } 688 parent = NULL; 689 for (;;) { 690 if (rnode == NULL) 691 panic("vm_radix_remove: impossible to locate the key"); 692 slot = vm_radix_slot(index, rnode->rn_clev); 693 if (vm_radix_isleaf(rnode->rn_child[slot])) { 694 m = vm_radix_topage(rnode->rn_child[slot]); 695 if (m->pindex != index) 696 panic("%s: invalid key found", __func__); 697 rnode->rn_child[slot] = NULL; 698 rnode->rn_count--; 699 if (rnode->rn_count > 1) 700 break; 701 for (i = 0; i < VM_RADIX_COUNT; i++) 702 if (rnode->rn_child[i] != NULL) 703 break; 704 KASSERT(i != VM_RADIX_COUNT, 705 ("%s: invalid node configuration", __func__)); 706 if (parent == NULL) 707 vm_radix_setroot(rtree, rnode->rn_child[i]); 708 else { 709 slot = vm_radix_slot(index, parent->rn_clev); 710 KASSERT(parent->rn_child[slot] == rnode, 711 ("%s: invalid child value", __func__)); 712 parent->rn_child[slot] = rnode->rn_child[i]; 713 } 714 rnode->rn_count--; 715 rnode->rn_child[i] = NULL; 716 vm_radix_node_put(rnode); 717 break; 718 } 719 parent = rnode; 720 rnode = rnode->rn_child[slot]; 721 } 722 } 723 724 /* 725 * Remove and free all the nodes from the radix tree. 726 * This function is recursive but there is a tight control on it as the 727 * maximum depth of the tree is fixed. 728 */ 729 void 730 vm_radix_reclaim_allnodes(struct vm_radix *rtree) 731 { 732 struct vm_radix_node *root; 733 734 root = vm_radix_getroot(rtree); 735 if (root == NULL) 736 return; 737 vm_radix_setroot(rtree, NULL); 738 if (!vm_radix_isleaf(root)) 739 vm_radix_reclaim_allnodes_int(root); 740 } 741 742 #ifdef DDB 743 /* 744 * Show details about the given radix node. 745 */ 746 DB_SHOW_COMMAND(radixnode, db_show_radixnode) 747 { 748 struct vm_radix_node *rnode; 749 int i; 750 751 if (!have_addr) 752 return; 753 rnode = (struct vm_radix_node *)addr; 754 db_printf("radixnode %p, owner %jx, children count %u, level %u:\n", 755 (void *)rnode, (uintmax_t)rnode->rn_owner, rnode->rn_count, 756 rnode->rn_clev); 757 for (i = 0; i < VM_RADIX_COUNT; i++) 758 if (rnode->rn_child[i] != NULL) 759 db_printf("slot: %d, val: %p, page: %p, clev: %d\n", 760 i, (void *)rnode->rn_child[i], 761 vm_radix_isleaf(rnode->rn_child[i]) ? 762 vm_radix_topage(rnode->rn_child[i]) : NULL, 763 rnode->rn_clev); 764 } 765 #endif /* DDB */ 766