vm_radix.c revision 254141
1226645Sattilio/* 2246726Sattilio * Copyright (c) 2013 EMC Corp. 3226930Sjeff * Copyright (c) 2011 Jeffrey Roberson <jeff@freebsd.org> 4226645Sattilio * Copyright (c) 2008 Mayur Shardul <mayur.shardul@gmail.com> 5226645Sattilio * All rights reserved. 6226645Sattilio * 7226645Sattilio * Redistribution and use in source and binary forms, with or without 8226645Sattilio * modification, are permitted provided that the following conditions 9226645Sattilio * are met: 10226645Sattilio * 1. Redistributions of source code must retain the above copyright 11226645Sattilio * notice, this list of conditions and the following disclaimer. 12226645Sattilio * 2. Redistributions in binary form must reproduce the above copyright 13226645Sattilio * notice, this list of conditions and the following disclaimer in the 14226645Sattilio * documentation and/or other materials provided with the distribution. 15226645Sattilio * 16226645Sattilio * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17226645Sattilio * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18226645Sattilio * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19226645Sattilio * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20226645Sattilio * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21226645Sattilio * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22226645Sattilio * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23226645Sattilio * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24226645Sattilio * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25226645Sattilio * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26226645Sattilio * SUCH DAMAGE. 27226645Sattilio * 28226645Sattilio */ 29226645Sattilio 30226645Sattilio/* 31246726Sattilio * Path-compressed radix trie implementation. 32246726Sattilio * The following code is not generalized into a general purpose library 33246726Sattilio * because there are way too many parameters embedded that should really 34246726Sattilio * be decided by the library consumers. At the same time, consumers 35246726Sattilio * of this code must achieve highest possible performance. 36246726Sattilio * 37246726Sattilio * The implementation takes into account the following rationale: 38248424Sattilio * - Size of the nodes should be as small as possible but still big enough 39248424Sattilio * to avoid a large maximum depth for the trie. This is a balance 40248424Sattilio * between the necessity to not wire too much physical memory for the nodes 41248424Sattilio * and the necessity to avoid too much cache pollution during the trie 42248424Sattilio * operations. 43248424Sattilio * - There is not a huge bias toward the number of lookup operations over 44248424Sattilio * the number of insert and remove operations. This basically implies 45248424Sattilio * that optimizations supposedly helping one operation but hurting the 46248424Sattilio * other might be carefully evaluated. 47248424Sattilio * - On average not many nodes are expected to be fully populated, hence 48248424Sattilio * level compression may just complicate things. 49226645Sattilio */ 50226645Sattilio 51226645Sattilio#include <sys/cdefs.h> 52248448Sattilio__FBSDID("$FreeBSD: head/sys/vm/vm_radix.c 254141 2013-08-09 11:28:55Z attilio $"); 53226645Sattilio 54246726Sattilio#include "opt_ddb.h" 55246726Sattilio 56226645Sattilio#include <sys/param.h> 57226645Sattilio#include <sys/systm.h> 58226645Sattilio#include <sys/kernel.h> 59246840Sattilio#include <sys/vmmeter.h> 60246726Sattilio 61226873Sattilio#include <vm/uma.h> 62226645Sattilio#include <vm/vm.h> 63226876Sjeff#include <vm/vm_param.h> 64226873Sattilio#include <vm/vm_page.h> 65226645Sattilio#include <vm/vm_radix.h> 66226645Sattilio 67246726Sattilio#ifdef DDB 68246726Sattilio#include <ddb/ddb.h> 69246726Sattilio#endif 70226645Sattilio 71233034Sattilio/* 72247771Salc * These widths should allow the pointers to a node's children to fit within 73247771Salc * a single cache line. The extra levels from a narrow width should not be 74247771Salc * a problem thanks to path compression. 75233034Sattilio */ 76246726Sattilio#ifdef __LP64__ 77246726Sattilio#define VM_RADIX_WIDTH 4 78233034Sattilio#else 79246726Sattilio#define VM_RADIX_WIDTH 3 80233034Sattilio#endif 81233034Sattilio 82232326Sattilio#define VM_RADIX_COUNT (1 << VM_RADIX_WIDTH) 83232326Sattilio#define VM_RADIX_MASK (VM_RADIX_COUNT - 1) 84246726Sattilio#define VM_RADIX_LIMIT \ 85246726Sattilio (howmany((sizeof(vm_pindex_t) * NBBY), VM_RADIX_WIDTH) - 1) 86232326Sattilio 87232326Sattilio/* Flag bits stored in node pointers. */ 88246726Sattilio#define VM_RADIX_ISLEAF 0x1 89246726Sattilio#define VM_RADIX_FLAGS 0x1 90246726Sattilio#define VM_RADIX_PAD VM_RADIX_FLAGS 91232326Sattilio 92246726Sattilio/* Returns one unit associated with specified level. */ 93246726Sattilio#define VM_RADIX_UNITLEVEL(lev) \ 94250520Salc ((vm_pindex_t)1 << ((lev) * VM_RADIX_WIDTH)) 95232326Sattilio 96232326Sattiliostruct vm_radix_node { 97246726Sattilio vm_pindex_t rn_owner; /* Owner of record. */ 98246726Sattilio uint16_t rn_count; /* Valid children. */ 99246726Sattilio uint16_t rn_clev; /* Current level. */ 100249221Salc void *rn_child[VM_RADIX_COUNT]; /* Child nodes. */ 101232326Sattilio}; 102232326Sattilio 103226873Sattiliostatic uma_zone_t vm_radix_node_zone; 104226645Sattilio 105246794Sattilio/* 106254141Sattilio * Allocate a radix node. 107246726Sattilio */ 108246726Sattiliostatic __inline struct vm_radix_node * 109246726Sattiliovm_radix_node_get(vm_pindex_t owner, uint16_t count, uint16_t clevel) 110226873Sattilio{ 111246726Sattilio struct vm_radix_node *rnode; 112226645Sattilio 113254141Sattilio rnode = uma_zalloc(vm_radix_node_zone, M_NOWAIT | M_ZERO); 114247742Sattilio if (rnode == NULL) 115254141Sattilio return (NULL); 116246726Sattilio rnode->rn_owner = owner; 117246726Sattilio rnode->rn_count = count; 118246726Sattilio rnode->rn_clev = clevel; 119246726Sattilio return (rnode); 120246726Sattilio} 121226873Sattilio 122246726Sattilio/* 123246726Sattilio * Free radix node. 124246726Sattilio */ 125246726Sattiliostatic __inline void 126246726Sattiliovm_radix_node_put(struct vm_radix_node *rnode) 127246726Sattilio{ 128246726Sattilio 129246726Sattilio uma_zfree(vm_radix_node_zone, rnode); 130226873Sattilio} 131226873Sattilio 132246726Sattilio/* 133246726Sattilio * Return the position in the array for a given level. 134246726Sattilio */ 135246726Sattiliostatic __inline int 136246726Sattiliovm_radix_slot(vm_pindex_t index, uint16_t level) 137226873Sattilio{ 138226873Sattilio 139250520Salc return ((index >> (level * VM_RADIX_WIDTH)) & VM_RADIX_MASK); 140226873Sattilio} 141226873Sattilio 142246726Sattilio/* Trims the key after the specified level. */ 143246726Sattiliostatic __inline vm_pindex_t 144246726Sattiliovm_radix_trimkey(vm_pindex_t index, uint16_t level) 145226873Sattilio{ 146246726Sattilio vm_pindex_t ret; 147226873Sattilio 148246726Sattilio ret = index; 149250520Salc if (level > 0) { 150250520Salc ret >>= level * VM_RADIX_WIDTH; 151250520Salc ret <<= level * VM_RADIX_WIDTH; 152246726Sattilio } 153246726Sattilio return (ret); 154226873Sattilio} 155226873Sattilio 156226645Sattilio/* 157246726Sattilio * Get the root node for a radix tree. 158226873Sattilio */ 159246726Sattiliostatic __inline struct vm_radix_node * 160246726Sattiliovm_radix_getroot(struct vm_radix *rtree) 161226873Sattilio{ 162226873Sattilio 163249221Salc return ((struct vm_radix_node *)rtree->rt_root); 164226873Sattilio} 165226873Sattilio 166226873Sattilio/* 167246726Sattilio * Set the root node for a radix tree. 168226645Sattilio */ 169246726Sattiliostatic __inline void 170246726Sattiliovm_radix_setroot(struct vm_radix *rtree, struct vm_radix_node *rnode) 171226645Sattilio{ 172226645Sattilio 173246726Sattilio rtree->rt_root = (uintptr_t)rnode; 174226645Sattilio} 175226645Sattilio 176226645Sattilio/* 177248728Salc * Returns TRUE if the specified radix node is a leaf and FALSE otherwise. 178248728Salc */ 179248728Salcstatic __inline boolean_t 180248728Salcvm_radix_isleaf(struct vm_radix_node *rnode) 181248728Salc{ 182248728Salc 183248728Salc return (((uintptr_t)rnode & VM_RADIX_ISLEAF) != 0); 184248728Salc} 185248728Salc 186248728Salc/* 187249038Salc * Returns the associated page extracted from rnode. 188226645Sattilio */ 189246726Sattiliostatic __inline vm_page_t 190249038Salcvm_radix_topage(struct vm_radix_node *rnode) 191226645Sattilio{ 192226645Sattilio 193249038Salc return ((vm_page_t)((uintptr_t)rnode & ~VM_RADIX_FLAGS)); 194226645Sattilio} 195226645Sattilio 196226645Sattilio/* 197247771Salc * Adds the page as a child of the provided node. 198226645Sattilio */ 199246726Sattiliostatic __inline void 200246726Sattiliovm_radix_addpage(struct vm_radix_node *rnode, vm_pindex_t index, uint16_t clev, 201246726Sattilio vm_page_t page) 202226645Sattilio{ 203246726Sattilio int slot; 204226645Sattilio 205246726Sattilio slot = vm_radix_slot(index, clev); 206246726Sattilio rnode->rn_child[slot] = (void *)((uintptr_t)page | VM_RADIX_ISLEAF); 207226645Sattilio} 208226645Sattilio 209233034Sattilio/* 210246726Sattilio * Returns the slot where two keys differ. 211246726Sattilio * It cannot accept 2 equal keys. 212233034Sattilio */ 213246726Sattiliostatic __inline uint16_t 214246726Sattiliovm_radix_keydiff(vm_pindex_t index1, vm_pindex_t index2) 215226873Sattilio{ 216246726Sattilio uint16_t clev; 217226873Sattilio 218246726Sattilio KASSERT(index1 != index2, ("%s: passing the same key value %jx", 219246726Sattilio __func__, (uintmax_t)index1)); 220233034Sattilio 221246726Sattilio index1 ^= index2; 222250520Salc for (clev = VM_RADIX_LIMIT;; clev--) 223250334Salc if (vm_radix_slot(index1, clev) != 0) 224246726Sattilio return (clev); 225226873Sattilio} 226226873Sattilio 227226645Sattilio/* 228246726Sattilio * Returns TRUE if it can be determined that key does not belong to the 229247771Salc * specified rnode. Otherwise, returns FALSE. 230226876Sjeff */ 231246726Sattiliostatic __inline boolean_t 232246726Sattiliovm_radix_keybarr(struct vm_radix_node *rnode, vm_pindex_t idx) 233226876Sjeff{ 234226876Sjeff 235250520Salc if (rnode->rn_clev < VM_RADIX_LIMIT) { 236250520Salc idx = vm_radix_trimkey(idx, rnode->rn_clev + 1); 237249211Salc return (idx != rnode->rn_owner); 238246726Sattilio } 239246726Sattilio return (FALSE); 240226876Sjeff} 241226876Sjeff 242226876Sjeff/* 243247773Salc * Internal helper for vm_radix_reclaim_allnodes(). 244247769Salc * This function is recursive. 245246726Sattilio */ 246226980Sattiliostatic void 247246726Sattiliovm_radix_reclaim_allnodes_int(struct vm_radix_node *rnode) 248226980Sattilio{ 249226980Sattilio int slot; 250226980Sattilio 251248684Salc KASSERT(rnode->rn_count <= VM_RADIX_COUNT, 252248684Salc ("vm_radix_reclaim_allnodes_int: bad count in rnode %p", rnode)); 253248684Salc for (slot = 0; rnode->rn_count != 0; slot++) { 254226980Sattilio if (rnode->rn_child[slot] == NULL) 255226980Sattilio continue; 256248728Salc if (!vm_radix_isleaf(rnode->rn_child[slot])) 257246726Sattilio vm_radix_reclaim_allnodes_int(rnode->rn_child[slot]); 258248431Salc rnode->rn_child[slot] = NULL; 259226980Sattilio rnode->rn_count--; 260226980Sattilio } 261226980Sattilio vm_radix_node_put(rnode); 262226980Sattilio} 263226980Sattilio 264246836Sattilio#ifdef INVARIANTS 265226876Sjeff/* 266246836Sattilio * Radix node zone destructor. 267246836Sattilio */ 268246836Sattiliostatic void 269246836Sattiliovm_radix_node_zone_dtor(void *mem, int size __unused, void *arg __unused) 270246836Sattilio{ 271246836Sattilio struct vm_radix_node *rnode; 272248431Salc int slot; 273246836Sattilio 274246836Sattilio rnode = mem; 275246836Sattilio KASSERT(rnode->rn_count == 0, 276248431Salc ("vm_radix_node_put: rnode %p has %d children", rnode, 277246836Sattilio rnode->rn_count)); 278248431Salc for (slot = 0; slot < VM_RADIX_COUNT; slot++) 279248431Salc KASSERT(rnode->rn_child[slot] == NULL, 280248431Salc ("vm_radix_node_put: rnode %p has a child", rnode)); 281246836Sattilio} 282246836Sattilio#endif 283246836Sattilio 284254141Sattilio#ifndef UMA_MD_SMALL_ALLOC 285246836Sattilio/* 286254141Sattilio * Reserve the KVA necessary to satisfy the node allocation. 287254141Sattilio * This is mandatory in architectures not supporting direct 288254141Sattilio * mapping as they will need otherwise to carve into the kernel maps for 289254141Sattilio * every node allocation, resulting into deadlocks for consumers already 290254141Sattilio * working with kernel maps. 291248431Salc */ 292246794Sattiliostatic void 293254141Sattiliovm_radix_reserve_kva(void *arg __unused) 294246726Sattilio{ 295246726Sattilio 296249605Salc /* 297249605Salc * Calculate the number of reserved nodes, discounting the pages that 298249605Salc * are needed to store them. 299249605Salc */ 300254141Sattilio if (!uma_zone_reserve_kva(vm_radix_node_zone, 301254141Sattilio ((vm_paddr_t)cnt.v_page_count * PAGE_SIZE) / (PAGE_SIZE + 302254141Sattilio sizeof(struct vm_radix_node)))) 303254141Sattilio panic("%s: unable to reserve KVA", __func__); 304247742Sattilio} 305254141SattilioSYSINIT(vm_radix_reserve_kva, SI_SUB_KMEM, SI_ORDER_SECOND, 306254141Sattilio vm_radix_reserve_kva, NULL); 307254141Sattilio#endif 308247742Sattilio 309247742Sattilio/* 310247742Sattilio * Initialize the UMA slab zone. 311247742Sattilio * Until vm_radix_prealloc() is called, the zone will be served by the 312247742Sattilio * UMA boot-time pre-allocated pool of pages. 313247742Sattilio */ 314247742Sattiliovoid 315247742Sattiliovm_radix_init(void) 316247742Sattilio{ 317247742Sattilio 318246726Sattilio vm_radix_node_zone = uma_zcreate("RADIX NODE", 319246726Sattilio sizeof(struct vm_radix_node), NULL, 320246726Sattilio#ifdef INVARIANTS 321246726Sattilio vm_radix_node_zone_dtor, 322246726Sattilio#else 323246726Sattilio NULL, 324246726Sattilio#endif 325254141Sattilio NULL, NULL, VM_RADIX_PAD, UMA_ZONE_VM); 326246726Sattilio} 327246726Sattilio 328246726Sattilio/* 329247771Salc * Inserts the key-value pair into the trie. 330226645Sattilio * Panics if the key already exists. 331226645Sattilio */ 332254141Sattilioint 333248428Salcvm_radix_insert(struct vm_radix *rtree, vm_page_t page) 334226645Sattilio{ 335248428Salc vm_pindex_t index, newind; 336249502Salc void **parentp; 337249502Salc struct vm_radix_node *rnode, *tmp; 338246726Sattilio vm_page_t m; 339236763Sattilio int slot; 340246726Sattilio uint16_t clev; 341226645Sattilio 342248428Salc index = page->pindex; 343248222Sattilio 344254141Sattiliorestart: 345254141Sattilio 346226645Sattilio /* 347246726Sattilio * The owner of record for root is not really important because it 348246726Sattilio * will never be used. 349226645Sattilio */ 350246726Sattilio rnode = vm_radix_getroot(rtree); 351246726Sattilio if (rnode == NULL) { 352249502Salc rtree->rt_root = (uintptr_t)page | VM_RADIX_ISLEAF; 353254141Sattilio return (0); 354246726Sattilio } 355249502Salc parentp = (void **)&rtree->rt_root; 356249502Salc for (;;) { 357249502Salc if (vm_radix_isleaf(rnode)) { 358249502Salc m = vm_radix_topage(rnode); 359246726Sattilio if (m->pindex == index) 360246726Sattilio panic("%s: key %jx is already present", 361246726Sattilio __func__, (uintmax_t)index); 362246726Sattilio clev = vm_radix_keydiff(m->pindex, index); 363254141Sattilio 364254141Sattilio /* 365254141Sattilio * During node allocation the trie that is being 366254141Sattilio * walked can be modified because of recursing radix 367254141Sattilio * trie operations. 368254141Sattilio * If this is the case, the recursing functions signal 369254141Sattilio * such situation and the insert operation must 370254141Sattilio * start from scratch again. 371254141Sattilio * The freed radix node will then be in the UMA 372254141Sattilio * caches very likely to avoid the same situation 373254141Sattilio * to happen. 374254141Sattilio */ 375254141Sattilio rtree->rt_flags |= RT_INSERT_INPROG; 376246726Sattilio tmp = vm_radix_node_get(vm_radix_trimkey(index, 377250520Salc clev + 1), 2, clev); 378254141Sattilio rtree->rt_flags &= ~RT_INSERT_INPROG; 379254141Sattilio if (tmp == NULL) { 380254141Sattilio rtree->rt_flags &= ~RT_TRIE_MODIFIED; 381254141Sattilio return (ENOMEM); 382254141Sattilio } 383254141Sattilio if ((rtree->rt_flags & RT_TRIE_MODIFIED) != 0) { 384254141Sattilio rtree->rt_flags &= ~RT_TRIE_MODIFIED; 385254141Sattilio tmp->rn_count = 0; 386254141Sattilio vm_radix_node_put(tmp); 387254141Sattilio goto restart; 388254141Sattilio } 389249502Salc *parentp = tmp; 390246726Sattilio vm_radix_addpage(tmp, index, clev, page); 391246726Sattilio vm_radix_addpage(tmp, m->pindex, clev, m); 392254141Sattilio return (0); 393249502Salc } else if (vm_radix_keybarr(rnode, index)) 394249502Salc break; 395249502Salc slot = vm_radix_slot(index, rnode->rn_clev); 396226645Sattilio if (rnode->rn_child[slot] == NULL) { 397236760Sattilio rnode->rn_count++; 398246726Sattilio vm_radix_addpage(rnode, index, rnode->rn_clev, page); 399254141Sattilio return (0); 400246726Sattilio } 401249502Salc parentp = &rnode->rn_child[slot]; 402226645Sattilio rnode = rnode->rn_child[slot]; 403249502Salc } 404226645Sattilio 405246726Sattilio /* 406246726Sattilio * A new node is needed because the right insertion level is reached. 407246726Sattilio * Setup the new intermediate node and add the 2 children: the 408246726Sattilio * new object and the older edge. 409246726Sattilio */ 410249182Salc newind = rnode->rn_owner; 411249182Salc clev = vm_radix_keydiff(newind, index); 412254141Sattilio 413254141Sattilio /* See the comments above. */ 414254141Sattilio rtree->rt_flags |= RT_INSERT_INPROG; 415254141Sattilio tmp = vm_radix_node_get(vm_radix_trimkey(index, clev + 1), 2, clev); 416254141Sattilio rtree->rt_flags &= ~RT_INSERT_INPROG; 417254141Sattilio if (tmp == NULL) { 418254141Sattilio rtree->rt_flags &= ~RT_TRIE_MODIFIED; 419254141Sattilio return (ENOMEM); 420254141Sattilio } 421254141Sattilio if ((rtree->rt_flags & RT_TRIE_MODIFIED) != 0) { 422254141Sattilio rtree->rt_flags &= ~RT_TRIE_MODIFIED; 423254141Sattilio tmp->rn_count = 0; 424254141Sattilio vm_radix_node_put(tmp); 425254141Sattilio goto restart; 426254141Sattilio } 427249502Salc *parentp = tmp; 428249182Salc vm_radix_addpage(tmp, index, clev, page); 429246726Sattilio slot = vm_radix_slot(newind, clev); 430249182Salc tmp->rn_child[slot] = rnode; 431254141Sattilio return (0); 432226645Sattilio} 433226645Sattilio 434226645Sattilio/* 435247771Salc * Returns the value stored at the index. If the index is not present, 436226645Sattilio * NULL is returned. 437226645Sattilio */ 438246430Sattiliovm_page_t 439238245Sattiliovm_radix_lookup(struct vm_radix *rtree, vm_pindex_t index) 440226645Sattilio{ 441226645Sattilio struct vm_radix_node *rnode; 442246726Sattilio vm_page_t m; 443226645Sattilio int slot; 444226645Sattilio 445246726Sattilio rnode = vm_radix_getroot(rtree); 446246795Sattilio while (rnode != NULL) { 447249038Salc if (vm_radix_isleaf(rnode)) { 448249038Salc m = vm_radix_topage(rnode); 449246726Sattilio if (m->pindex == index) 450246726Sattilio return (m); 451246726Sattilio else 452249427Salc break; 453249427Salc } else if (vm_radix_keybarr(rnode, index)) 454249427Salc break; 455249427Salc slot = vm_radix_slot(index, rnode->rn_clev); 456249427Salc rnode = rnode->rn_child[slot]; 457226645Sattilio } 458246726Sattilio return (NULL); 459226645Sattilio} 460226645Sattilio 461226645Sattilio/* 462247771Salc * Look up the nearest entry at a position bigger than or equal to index. 463226645Sattilio */ 464246726Sattiliovm_page_t 465246726Sattiliovm_radix_lookup_ge(struct vm_radix *rtree, vm_pindex_t index) 466226645Sattilio{ 467250259Salc struct vm_radix_node *stack[VM_RADIX_LIMIT]; 468246726Sattilio vm_pindex_t inc; 469246726Sattilio vm_page_t m; 470249038Salc struct vm_radix_node *child, *rnode; 471246726Sattilio#ifdef INVARIANTS 472246726Sattilio int loops = 0; 473246726Sattilio#endif 474250259Salc int slot, tos; 475226645Sattilio 476249427Salc rnode = vm_radix_getroot(rtree); 477249427Salc if (rnode == NULL) 478249427Salc return (NULL); 479249427Salc else if (vm_radix_isleaf(rnode)) { 480249427Salc m = vm_radix_topage(rnode); 481249427Salc if (m->pindex >= index) 482249427Salc return (m); 483249427Salc else 484249427Salc return (NULL); 485249427Salc } 486250259Salc tos = 0; 487249427Salc for (;;) { 488246726Sattilio /* 489249986Salc * If the keys differ before the current bisection node, 490249986Salc * then the search key might rollback to the earliest 491249986Salc * available bisection node or to the smallest key 492249986Salc * in the current node (if the owner is bigger than the 493246726Sattilio * search key). 494246726Sattilio */ 495247770Salc if (vm_radix_keybarr(rnode, index)) { 496246726Sattilio if (index > rnode->rn_owner) { 497250259Salcascend: 498250259Salc KASSERT(++loops < 1000, 499250259Salc ("vm_radix_lookup_ge: too many loops")); 500250259Salc 501250259Salc /* 502250259Salc * Pop nodes from the stack until either the 503250259Salc * stack is empty or a node that could have a 504250259Salc * matching descendant is found. 505250259Salc */ 506250259Salc do { 507250259Salc if (tos == 0) 508250259Salc return (NULL); 509250259Salc rnode = stack[--tos]; 510250259Salc } while (vm_radix_slot(index, 511250259Salc rnode->rn_clev) == (VM_RADIX_COUNT - 1)); 512250259Salc 513250259Salc /* 514250259Salc * The following computation cannot overflow 515250259Salc * because index's slot at the current level 516250259Salc * is less than VM_RADIX_COUNT - 1. 517250259Salc */ 518250259Salc index = vm_radix_trimkey(index, 519250259Salc rnode->rn_clev); 520250259Salc index += VM_RADIX_UNITLEVEL(rnode->rn_clev); 521246726Sattilio } else 522249986Salc index = rnode->rn_owner; 523250259Salc KASSERT(!vm_radix_keybarr(rnode, index), 524250259Salc ("vm_radix_lookup_ge: keybarr failed")); 525246726Sattilio } 526246726Sattilio slot = vm_radix_slot(index, rnode->rn_clev); 527249038Salc child = rnode->rn_child[slot]; 528249038Salc if (vm_radix_isleaf(child)) { 529249038Salc m = vm_radix_topage(child); 530249038Salc if (m->pindex >= index) 531249038Salc return (m); 532249038Salc } else if (child != NULL) 533249038Salc goto descend; 534246726Sattilio 535226645Sattilio /* 536246726Sattilio * Look for an available edge or page within the current 537246726Sattilio * bisection node. 538246726Sattilio */ 539246726Sattilio if (slot < (VM_RADIX_COUNT - 1)) { 540246726Sattilio inc = VM_RADIX_UNITLEVEL(rnode->rn_clev); 541246726Sattilio index = vm_radix_trimkey(index, rnode->rn_clev); 542249038Salc do { 543249038Salc index += inc; 544249038Salc slot++; 545249038Salc child = rnode->rn_child[slot]; 546249038Salc if (vm_radix_isleaf(child)) { 547249038Salc m = vm_radix_topage(child); 548249038Salc if (m->pindex >= index) 549249038Salc return (m); 550249038Salc } else if (child != NULL) 551249038Salc goto descend; 552249038Salc } while (slot < (VM_RADIX_COUNT - 1)); 553246726Sattilio } 554249038Salc KASSERT(child == NULL || vm_radix_isleaf(child), 555249038Salc ("vm_radix_lookup_ge: child is radix node")); 556230750Sattilio 557246726Sattilio /* 558250259Salc * If a page or edge bigger than the search slot is not found 559250259Salc * in the current node, ascend to the next higher-level node. 560246726Sattilio */ 561250259Salc goto ascend; 562249038Salcdescend: 563250520Salc KASSERT(rnode->rn_clev > 0, 564250259Salc ("vm_radix_lookup_ge: pushing leaf's parent")); 565250259Salc KASSERT(tos < VM_RADIX_LIMIT, 566250259Salc ("vm_radix_lookup_ge: stack overflow")); 567250259Salc stack[tos++] = rnode; 568249038Salc rnode = child; 569226645Sattilio } 570226645Sattilio} 571226645Sattilio 572226645Sattilio/* 573247771Salc * Look up the nearest entry at a position less than or equal to index. 574226645Sattilio */ 575246430Sattiliovm_page_t 576238245Sattiliovm_radix_lookup_le(struct vm_radix *rtree, vm_pindex_t index) 577226645Sattilio{ 578250259Salc struct vm_radix_node *stack[VM_RADIX_LIMIT]; 579246726Sattilio vm_pindex_t inc; 580246726Sattilio vm_page_t m; 581249038Salc struct vm_radix_node *child, *rnode; 582246726Sattilio#ifdef INVARIANTS 583246726Sattilio int loops = 0; 584246726Sattilio#endif 585250259Salc int slot, tos; 586226645Sattilio 587249427Salc rnode = vm_radix_getroot(rtree); 588249427Salc if (rnode == NULL) 589249427Salc return (NULL); 590249427Salc else if (vm_radix_isleaf(rnode)) { 591249427Salc m = vm_radix_topage(rnode); 592249427Salc if (m->pindex <= index) 593249427Salc return (m); 594249427Salc else 595249427Salc return (NULL); 596249427Salc } 597250259Salc tos = 0; 598249427Salc for (;;) { 599226646Sjeff /* 600249986Salc * If the keys differ before the current bisection node, 601249986Salc * then the search key might rollback to the earliest 602249986Salc * available bisection node or to the largest key 603249986Salc * in the current node (if the owner is smaller than the 604246726Sattilio * search key). 605226646Sjeff */ 606247770Salc if (vm_radix_keybarr(rnode, index)) { 607246726Sattilio if (index > rnode->rn_owner) { 608249986Salc index = rnode->rn_owner + VM_RADIX_COUNT * 609250259Salc VM_RADIX_UNITLEVEL(rnode->rn_clev); 610249986Salc } else { 611250259Salcascend: 612250259Salc KASSERT(++loops < 1000, 613250259Salc ("vm_radix_lookup_le: too many loops")); 614250259Salc 615250259Salc /* 616250259Salc * Pop nodes from the stack until either the 617250259Salc * stack is empty or a node that could have a 618250259Salc * matching descendant is found. 619250259Salc */ 620250259Salc do { 621250259Salc if (tos == 0) 622250259Salc return (NULL); 623250259Salc rnode = stack[--tos]; 624250259Salc } while (vm_radix_slot(index, 625250259Salc rnode->rn_clev) == 0); 626250259Salc 627250259Salc /* 628250259Salc * The following computation cannot overflow 629250259Salc * because index's slot at the current level 630250259Salc * is greater than 0. 631250259Salc */ 632250259Salc index = vm_radix_trimkey(index, 633250259Salc rnode->rn_clev); 634249986Salc } 635250259Salc index--; 636250259Salc KASSERT(!vm_radix_keybarr(rnode, index), 637250259Salc ("vm_radix_lookup_le: keybarr failed")); 638246726Sattilio } 639246726Sattilio slot = vm_radix_slot(index, rnode->rn_clev); 640249038Salc child = rnode->rn_child[slot]; 641249038Salc if (vm_radix_isleaf(child)) { 642249038Salc m = vm_radix_topage(child); 643249038Salc if (m->pindex <= index) 644249038Salc return (m); 645249038Salc } else if (child != NULL) 646249038Salc goto descend; 647246726Sattilio 648246726Sattilio /* 649246726Sattilio * Look for an available edge or page within the current 650246726Sattilio * bisection node. 651246726Sattilio */ 652246726Sattilio if (slot > 0) { 653246726Sattilio inc = VM_RADIX_UNITLEVEL(rnode->rn_clev); 654246726Sattilio index |= inc - 1; 655249038Salc do { 656249038Salc index -= inc; 657249038Salc slot--; 658249038Salc child = rnode->rn_child[slot]; 659249038Salc if (vm_radix_isleaf(child)) { 660249038Salc m = vm_radix_topage(child); 661249038Salc if (m->pindex <= index) 662249038Salc return (m); 663249038Salc } else if (child != NULL) 664249038Salc goto descend; 665249038Salc } while (slot > 0); 666226646Sjeff } 667249038Salc KASSERT(child == NULL || vm_radix_isleaf(child), 668249038Salc ("vm_radix_lookup_le: child is radix node")); 669246726Sattilio 670246726Sattilio /* 671250259Salc * If a page or edge smaller than the search slot is not found 672250259Salc * in the current node, ascend to the next higher-level node. 673246726Sattilio */ 674250259Salc goto ascend; 675249038Salcdescend: 676250520Salc KASSERT(rnode->rn_clev > 0, 677250259Salc ("vm_radix_lookup_le: pushing leaf's parent")); 678250259Salc KASSERT(tos < VM_RADIX_LIMIT, 679250259Salc ("vm_radix_lookup_le: stack overflow")); 680250259Salc stack[tos++] = rnode; 681249038Salc rnode = child; 682226646Sjeff } 683226645Sattilio} 684226645Sattilio 685226645Sattilio/* 686246726Sattilio * Remove the specified index from the tree. 687246726Sattilio * Panics if the key is not present. 688226645Sattilio */ 689236763Sattiliovoid 690238245Sattiliovm_radix_remove(struct vm_radix *rtree, vm_pindex_t index) 691226645Sattilio{ 692246726Sattilio struct vm_radix_node *rnode, *parent; 693246726Sattilio vm_page_t m; 694246726Sattilio int i, slot; 695226645Sattilio 696254141Sattilio /* 697254141Sattilio * Detect if a page is going to be removed from a trie which is 698254141Sattilio * already undergoing another trie operation. 699254141Sattilio * Right now this is only possible for vm_radix_remove() recursing 700254141Sattilio * into vm_radix_insert(). 701254141Sattilio * If this is the case, the caller must be notified about this 702254141Sattilio * situation. It will also takecare to update the RT_TRIE_MODIFIED 703254141Sattilio * accordingly. 704254141Sattilio * The RT_TRIE_MODIFIED bit is set here because the remove operation 705254141Sattilio * will always succeed. 706254141Sattilio */ 707254141Sattilio if ((rtree->rt_flags & RT_INSERT_INPROG) != 0) 708254141Sattilio rtree->rt_flags |= RT_TRIE_MODIFIED; 709254141Sattilio 710249502Salc rnode = vm_radix_getroot(rtree); 711249502Salc if (vm_radix_isleaf(rnode)) { 712249502Salc m = vm_radix_topage(rnode); 713249502Salc if (m->pindex != index) 714249502Salc panic("%s: invalid key found", __func__); 715249502Salc vm_radix_setroot(rtree, NULL); 716249502Salc return; 717249502Salc } 718246726Sattilio parent = NULL; 719236760Sattilio for (;;) { 720246726Sattilio if (rnode == NULL) 721246726Sattilio panic("vm_radix_remove: impossible to locate the key"); 722246726Sattilio slot = vm_radix_slot(index, rnode->rn_clev); 723249038Salc if (vm_radix_isleaf(rnode->rn_child[slot])) { 724249038Salc m = vm_radix_topage(rnode->rn_child[slot]); 725249038Salc if (m->pindex != index) 726249038Salc panic("%s: invalid key found", __func__); 727246726Sattilio rnode->rn_child[slot] = NULL; 728246726Sattilio rnode->rn_count--; 729246726Sattilio if (rnode->rn_count > 1) 730246726Sattilio break; 731246726Sattilio for (i = 0; i < VM_RADIX_COUNT; i++) 732246726Sattilio if (rnode->rn_child[i] != NULL) 733246726Sattilio break; 734246726Sattilio KASSERT(i != VM_RADIX_COUNT, 735246726Sattilio ("%s: invalid node configuration", __func__)); 736249502Salc if (parent == NULL) 737249502Salc vm_radix_setroot(rtree, rnode->rn_child[i]); 738249502Salc else { 739249502Salc slot = vm_radix_slot(index, parent->rn_clev); 740249502Salc KASSERT(parent->rn_child[slot] == rnode, 741249502Salc ("%s: invalid child value", __func__)); 742249502Salc parent->rn_child[slot] = rnode->rn_child[i]; 743249502Salc } 744246726Sattilio rnode->rn_count--; 745246726Sattilio rnode->rn_child[i] = NULL; 746246726Sattilio vm_radix_node_put(rnode); 747236760Sattilio break; 748236760Sattilio } 749246726Sattilio parent = rnode; 750246726Sattilio rnode = rnode->rn_child[slot]; 751236760Sattilio } 752226645Sattilio} 753226645Sattilio 754226645Sattilio/* 755226980Sattilio * Remove and free all the nodes from the radix tree. 756247771Salc * This function is recursive but there is a tight control on it as the 757226980Sattilio * maximum depth of the tree is fixed. 758226980Sattilio */ 759226980Sattiliovoid 760226980Sattiliovm_radix_reclaim_allnodes(struct vm_radix *rtree) 761226980Sattilio{ 762226980Sattilio struct vm_radix_node *root; 763226980Sattilio 764254141Sattilio KASSERT((rtree->rt_flags & RT_INSERT_INPROG) == 0, 765254141Sattilio ("vm_radix_reclaim_allnodes: unexpected trie recursion")); 766254141Sattilio 767246726Sattilio root = vm_radix_getroot(rtree); 768246726Sattilio if (root == NULL) 769226980Sattilio return; 770248684Salc vm_radix_setroot(rtree, NULL); 771249502Salc if (!vm_radix_isleaf(root)) 772249502Salc vm_radix_reclaim_allnodes_int(root); 773226980Sattilio} 774246726Sattilio 775254141Sattilio/* 776254141Sattilio * Replace an existing page into the trie with another one. 777254141Sattilio * Panics if the replacing page is not present or if the new page has an 778254141Sattilio * invalid key. 779254141Sattilio */ 780254141Sattiliovm_page_t 781254141Sattiliovm_radix_replace(struct vm_radix *rtree, vm_page_t newpage, vm_pindex_t index) 782254141Sattilio{ 783254141Sattilio struct vm_radix_node *rnode; 784254141Sattilio vm_page_t m; 785254141Sattilio int slot; 786254141Sattilio 787254141Sattilio KASSERT(newpage->pindex == index, ("%s: newpage index invalid", 788254141Sattilio __func__)); 789254141Sattilio 790254141Sattilio rnode = vm_radix_getroot(rtree); 791254141Sattilio if (rnode == NULL) 792254141Sattilio panic("%s: replacing page on an empty trie", __func__); 793254141Sattilio if (vm_radix_isleaf(rnode)) { 794254141Sattilio m = vm_radix_topage(rnode); 795254141Sattilio if (m->pindex != index) 796254141Sattilio panic("%s: original replacing root key not found", 797254141Sattilio __func__); 798254141Sattilio rtree->rt_root = (uintptr_t)newpage | VM_RADIX_ISLEAF; 799254141Sattilio return (m); 800254141Sattilio } 801254141Sattilio for (;;) { 802254141Sattilio slot = vm_radix_slot(index, rnode->rn_clev); 803254141Sattilio if (vm_radix_isleaf(rnode->rn_child[slot])) { 804254141Sattilio m = vm_radix_topage(rnode->rn_child[slot]); 805254141Sattilio if (m->pindex == index) { 806254141Sattilio rnode->rn_child[slot] = 807254141Sattilio (void *)((uintptr_t)newpage | 808254141Sattilio VM_RADIX_ISLEAF); 809254141Sattilio return (m); 810254141Sattilio } else 811254141Sattilio break; 812254141Sattilio } else if (rnode->rn_child[slot] == NULL || 813254141Sattilio vm_radix_keybarr(rnode->rn_child[slot], index)) 814254141Sattilio break; 815254141Sattilio rnode = rnode->rn_child[slot]; 816254141Sattilio } 817254141Sattilio panic("%s: original replacing page not found", __func__); 818254141Sattilio} 819254141Sattilio 820246726Sattilio#ifdef DDB 821246726Sattilio/* 822246837Sattilio * Show details about the given radix node. 823246726Sattilio */ 824246726SattilioDB_SHOW_COMMAND(radixnode, db_show_radixnode) 825246726Sattilio{ 826246726Sattilio struct vm_radix_node *rnode; 827246726Sattilio int i; 828246726Sattilio 829246726Sattilio if (!have_addr) 830246726Sattilio return; 831246726Sattilio rnode = (struct vm_radix_node *)addr; 832246726Sattilio db_printf("radixnode %p, owner %jx, children count %u, level %u:\n", 833246726Sattilio (void *)rnode, (uintmax_t)rnode->rn_owner, rnode->rn_count, 834246726Sattilio rnode->rn_clev); 835246726Sattilio for (i = 0; i < VM_RADIX_COUNT; i++) 836246726Sattilio if (rnode->rn_child[i] != NULL) 837246726Sattilio db_printf("slot: %d, val: %p, page: %p, clev: %d\n", 838246726Sattilio i, (void *)rnode->rn_child[i], 839249038Salc vm_radix_isleaf(rnode->rn_child[i]) ? 840249038Salc vm_radix_topage(rnode->rn_child[i]) : NULL, 841246726Sattilio rnode->rn_clev); 842246726Sattilio} 843246726Sattilio#endif /* DDB */ 844