1/*
2 * Copyright (c) 2008 Mayur Shardul <mayur.shardul@gmail.com>
3 * Copyright (c) 2011 Jeffrey Roberson <jeff@freebsd.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:

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40#include <sys/malloc.h>
41#include <sys/queue.h>
42#include <sys/param.h>
43#include <sys/lock.h>
44#include <sys/mutex.h>
45#include <sys/ktr.h>
46#include <vm/uma.h>
47#include <vm/vm.h>
48#include <vm/vm_extern.h>
49#include <vm/vm_kern.h>
50#include <vm/vm_page.h>
51#include <vm/vm_radix.h>
52#include <vm/vm_object.h>
53
54#include <sys/kdb.h>
55
56CTASSERT(sizeof(struct vm_radix_node) < PAGE_SIZE);
57
58static uma_zone_t vm_radix_node_zone;
59
60#if 0
61static void *
62vm_radix_node_zone_allocf(uma_zone_t zone, int size, uint8_t *flags, int wait)
63{
64 vm_offset_t addr;
65 vm_page_t m;
66 int pflags;
67
68 /* Inform UMA that this allocator uses kernel_map. */

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135 ("vm_radix_node_put: Freeing a node with %d children\n",
136 rnode->rn_count));
137}
138#endif
139
140/*
141 * Allocate a radix node. Initializes all elements to 0.
142 */
143static struct vm_radix_node *
144vm_radix_node_get(void)
145{
146
147 return (uma_zalloc(vm_radix_node_zone, M_NOWAIT | M_ZERO));
148}
149
150/*
151 * Free radix node.
152 */
153static void
154vm_radix_node_put(struct vm_radix_node *rnode)
155{
156
157 uma_zfree(vm_radix_node_zone, rnode);
158}
159
160/*
161 * Return the position in the array for a given level.
162 */
163static inline int
164vm_radix_slot(vm_pindex_t index, int level)
165{
166
167 return ((index >> (level * VM_RADIX_WIDTH)) & VM_RADIX_MASK);
168}
169
170void
171vm_radix_init(void)
172{
173
174 vm_radix_node_zone = uma_zcreate("RADIX NODE",
175 sizeof(struct vm_radix_node), NULL,
176#ifdef INVARIANTS
177 vm_radix_node_zone_dtor,
178#else
179 NULL,
180#endif
181 NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM);
182}
183
184/*
185 * Inserts the key-value pair in to the radix tree. Returns errno.
186 * Panics if the key already exists.
187 */
188int
189vm_radix_insert(struct vm_radix *rtree, vm_pindex_t index, void *val)
190{
191 struct vm_radix_node *rnode;
192 int slot;
193 int level;
194
195 CTR3(KTR_VM,
196 "insert: tree %p, index %p, val %p", rtree, (void *)index, val);
197 if (index == -1)
198 panic("vm_radix_insert: -1 is not a valid index.\n");
199 /*
200 * Increase the height by adding nodes at the root until
201 * there is sufficient space.
202 */
203 while (rtree->rt_height == 0 ||
204 index > VM_RADIX_MAX(rtree->rt_height)) {
205 CTR3(KTR_VM, "insert: expanding %jd > %jd height %d",
206 index, VM_RADIX_MAX(rtree->rt_height), rtree->rt_height);
207 /*
208 * Only allocate tree nodes if they are needed.
209 */
210 if (rtree->rt_root == NULL || rtree->rt_root->rn_count != 0) {
211 rnode = vm_radix_node_get();
212 if (rnode == NULL)
213 return (ENOMEM);
214 if (rtree->rt_root) {
215 rnode->rn_child[0] = rtree->rt_root;
216 rnode->rn_count = 1;
217 }
218 rtree->rt_root = rnode;
219 }
220 rtree->rt_height++;
221 KASSERT(rtree->rt_height <= VM_RADIX_LIMIT,
222 ("vm_radix_insert: Tree %p height %d too tall", rtree,
223 rtree->rt_height));
224 }
225
226 /* Now that the tree is tall enough, fill in the path to the index. */
227 rnode = rtree->rt_root;
228 for (level = rtree->rt_height - 1; level > 0; level--) {
229 slot = vm_radix_slot(index, level);
230 /* Add the required intermidiate nodes. */
231 if (rnode->rn_child[slot] == NULL) {
232 rnode->rn_child[slot] = vm_radix_node_get();
233 if (rnode->rn_child[slot] == NULL)
234 return (ENOMEM);
235 rnode->rn_count++;
236 }

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258 */
259void *
260vm_radix_lookup(struct vm_radix *rtree, vm_pindex_t index)
261{
262 struct vm_radix_node *rnode;
263 int slot;
264 int level;
265
266 if (index > VM_RADIX_MAX(rtree->rt_height))
267 return NULL;
268 level = rtree->rt_height - 1;
269 rnode = rtree->rt_root;
270 while (rnode) {
271 slot = vm_radix_slot(index, level);
272 CTR5(KTR_VM,
273 "lookup: tree %p, index %p, level %d, slot %d, child %p",
274 rtree, (void *)index, level, slot, rnode->rn_child[slot]);
275 if (level == 0)
276 return rnode->rn_child[slot];
277 rnode = rnode->rn_child[slot];

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299 int level;
300 void *val;
301 int outidx;
302 int loops = 0;
303
304 CTR3(KTR_VM, "lookupn: tree %p, start %p, end %p",
305 rtree, (void *)start, (void *)end);
306 outidx = 0;
307 max = VM_RADIX_MAX(rtree->rt_height);
308 if (start > max)
309 return 0;
310 if (end > max || end == 0)
311 end = max;
312restart:
313 loops++;
314 if (loops > 1000)
315 panic("vm_radix_lookupn: looping %d\n", loops);
316 /*
317 * Search the tree from the top for any leaf node holding an index
318 * between start and end.
319 */
320 level = rtree->rt_height - 1;
321 rnode = rtree->rt_root;
322 while (rnode) {
323 slot = vm_radix_slot(start, level);
324 CTR5(KTR_VM,
325 "lookupn: tree %p, index %p, level %d, slot %d, child %p",
326 rtree, (void *)start, level, slot, rnode->rn_child[slot]);
327 if (level == 0)
328 break;
329 /*

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399 vm_pindex_t max;
400 vm_pindex_t inc;
401 int slot;
402 int level;
403 int loops = 0;
404
405 CTR2(KTR_VM,
406 "lookup_le: tree %p, index %p", rtree, (void *)index);
407 if (rtree->rt_root == NULL)
408 return (NULL);
409 max = VM_RADIX_MAX(rtree->rt_height);
410 if (index > max || index == 0)
411 index = max;
412restart:
413 loops++;
414 if (loops > 1000)
415 panic("vm_radix_looku_le: looping %d\n", loops);
416 /*
417 * Search the tree from the top for any leaf node holding an index
418 * lower than 'index'.
419 */
420 level = rtree->rt_height - 1;
421 rnode = rtree->rt_root;
422 while (rnode) {
423 slot = vm_radix_slot(index, level);
424 CTR5(KTR_VM,
425 "lookup_le: tree %p, index %p, level %d, slot %d, child %p",
426 rtree, (void *)index, level, slot, rnode->rn_child[slot]);
427 if (level == 0)
428 break;
429 /*

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468 * Remove the specified index from the tree. If possible the height of the
469 * tree is adjusted after deletion. The value stored at index is returned
470 * panics if the key is not present.
471 */
472void *
473vm_radix_remove(struct vm_radix *rtree, vm_pindex_t index)
474{
475 struct vm_radix_node *stack[VM_RADIX_LIMIT];
476 struct vm_radix_node *rnode;
477 void *val;
478 int level;
479 int slot;
480
481 KASSERT(index <= VM_RADIX_MAX(rtree->rt_height),
482 ("vm_radix_remove: %p index %jd out of range %jd.",
483 rtree, index, VM_RADIX_MAX(rtree->rt_height)));
484 val = NULL;
485 rnode = rtree->rt_root;
486 level = rtree->rt_height - 1;
487 /*
488 * Find the node and record the path in stack.
489 */
490 while (level && rnode) {
491 stack[level] = rnode;
492 slot = vm_radix_slot(index, level);
493 rnode = rnode->rn_child[slot];
494 CTR5(KTR_VM,

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502
503 val = rnode->rn_child[slot];
504 for (;;) {
505 rnode->rn_child[slot] = NULL;
506 rnode->rn_count--;
507 if (rnode->rn_count > 0)
508 break;
509 vm_radix_node_put(rnode);
510 if (rnode == rtree->rt_root) {
511 rtree->rt_root = NULL;
512 rtree->rt_height = 0;
513 break;
514 }
515 rnode = stack[++level];
516 slot = vm_radix_slot(index, level);
517
518 }
519 return (val);
520}
521
522/*
523 * Attempts to reduce the height of the tree.
524 */
525void
526vm_radix_shrink(struct vm_radix *rtree)
527{
528 struct vm_radix_node *tmp;
529
530 if (rtree->rt_root == NULL)
531 return;
532
533 /* Adjust the height of the tree. */
534 while (rtree->rt_root->rn_count == 1 &&
535 rtree->rt_root->rn_child[0] != NULL) {
536 tmp = rtree->rt_root;
537 rtree->rt_root = tmp->rn_child[0];
538 rtree->rt_height--;
539 tmp->rn_count--;
540 vm_radix_node_put(tmp);
541 }
542 /* Finally see if we have an empty tree. */
543 if (rtree->rt_root->rn_count == 0) {
544 vm_radix_node_put(rtree->rt_root);
545 rtree->rt_root = NULL;
546 rtree->rt_height = 0;
547 }
548}