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vm_radix.c (249211) vm_radix.c (249221)
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>
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: head/sys/vm/vm_radix.c 249211 2013-04-06 18:04:35Z alc $");
52__FBSDID("$FreeBSD: head/sys/vm/vm_radix.c 249221 2013-04-07 01:30:51Z alc $");
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 << ((VM_RADIX_LIMIT - (lev)) * VM_RADIX_WIDTH))
95
96struct vm_radix_node {
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 << ((VM_RADIX_LIMIT - (lev)) * VM_RADIX_WIDTH))
95
96struct vm_radix_node {
97 void *rn_child[VM_RADIX_COUNT]; /* Child nodes. */
98 vm_pindex_t rn_owner; /* Owner of record. */
99 uint16_t rn_count; /* Valid children. */
100 uint16_t rn_clev; /* Current level. */
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
103static 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 */
109static __inline struct vm_radix_node *
110vm_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 */
139static __inline void
140vm_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 */
149static __inline int
150vm_radix_slot(vm_pindex_t index, uint16_t level)
151{
152
153 return ((index >> ((VM_RADIX_LIMIT - level) * VM_RADIX_WIDTH)) &
154 VM_RADIX_MASK);
155}
156
157/* Trims the key after the specified level. */
158static __inline vm_pindex_t
159vm_radix_trimkey(vm_pindex_t index, uint16_t level)
160{
161 vm_pindex_t ret;
162
163 ret = index;
164 if (level < VM_RADIX_LIMIT) {
165 ret >>= (VM_RADIX_LIMIT - level) * VM_RADIX_WIDTH;
166 ret <<= (VM_RADIX_LIMIT - level) * VM_RADIX_WIDTH;
167 }
168 return (ret);
169}
170
171/*
172 * Get the root node for a radix tree.
173 */
174static __inline struct vm_radix_node *
175vm_radix_getroot(struct vm_radix *rtree)
176{
177
101};
102
103static 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 */
109static __inline struct vm_radix_node *
110vm_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 */
139static __inline void
140vm_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 */
149static __inline int
150vm_radix_slot(vm_pindex_t index, uint16_t level)
151{
152
153 return ((index >> ((VM_RADIX_LIMIT - level) * VM_RADIX_WIDTH)) &
154 VM_RADIX_MASK);
155}
156
157/* Trims the key after the specified level. */
158static __inline vm_pindex_t
159vm_radix_trimkey(vm_pindex_t index, uint16_t level)
160{
161 vm_pindex_t ret;
162
163 ret = index;
164 if (level < VM_RADIX_LIMIT) {
165 ret >>= (VM_RADIX_LIMIT - level) * VM_RADIX_WIDTH;
166 ret <<= (VM_RADIX_LIMIT - level) * VM_RADIX_WIDTH;
167 }
168 return (ret);
169}
170
171/*
172 * Get the root node for a radix tree.
173 */
174static __inline struct vm_radix_node *
175vm_radix_getroot(struct vm_radix *rtree)
176{
177
178 return ((struct vm_radix_node *)(rtree->rt_root & ~VM_RADIX_FLAGS));
178 return ((struct vm_radix_node *)rtree->rt_root);
179}
180
181/*
182 * Set the root node for a radix tree.
183 */
184static __inline void
185vm_radix_setroot(struct vm_radix *rtree, struct vm_radix_node *rnode)
186{
187
188 rtree->rt_root = (uintptr_t)rnode;
189}
190
191/*
192 * Returns TRUE if the specified radix node is a leaf and FALSE otherwise.
193 */
194static __inline boolean_t
195vm_radix_isleaf(struct vm_radix_node *rnode)
196{
197
198 return (((uintptr_t)rnode & VM_RADIX_ISLEAF) != 0);
199}
200
201/*
202 * Returns the associated page extracted from rnode.
203 */
204static __inline vm_page_t
205vm_radix_topage(struct vm_radix_node *rnode)
206{
207
208 return ((vm_page_t)((uintptr_t)rnode & ~VM_RADIX_FLAGS));
209}
210
211/*
212 * Adds the page as a child of the provided node.
213 */
214static __inline void
215vm_radix_addpage(struct vm_radix_node *rnode, vm_pindex_t index, uint16_t clev,
216 vm_page_t page)
217{
218 int slot;
219
220 slot = vm_radix_slot(index, clev);
221 rnode->rn_child[slot] = (void *)((uintptr_t)page | VM_RADIX_ISLEAF);
222}
223
224/*
225 * Returns the slot where two keys differ.
226 * It cannot accept 2 equal keys.
227 */
228static __inline uint16_t
229vm_radix_keydiff(vm_pindex_t index1, vm_pindex_t index2)
230{
231 uint16_t clev;
232
233 KASSERT(index1 != index2, ("%s: passing the same key value %jx",
234 __func__, (uintmax_t)index1));
235
236 index1 ^= index2;
237 for (clev = 0; clev <= VM_RADIX_LIMIT ; clev++)
238 if (vm_radix_slot(index1, clev))
239 return (clev);
240 panic("%s: cannot reach this point", __func__);
241 return (0);
242}
243
244/*
245 * Returns TRUE if it can be determined that key does not belong to the
246 * specified rnode. Otherwise, returns FALSE.
247 */
248static __inline boolean_t
249vm_radix_keybarr(struct vm_radix_node *rnode, vm_pindex_t idx)
250{
251
252 if (rnode->rn_clev > 0) {
253 idx = vm_radix_trimkey(idx, rnode->rn_clev - 1);
254 return (idx != rnode->rn_owner);
255 }
256 return (FALSE);
257}
258
259/*
260 * Adjusts the idx key to the first upper level available, based on a valid
261 * initial level and map of available levels.
262 * Returns a value bigger than 0 to signal that there are not valid levels
263 * available.
264 */
265static __inline int
266vm_radix_addlev(vm_pindex_t *idx, boolean_t *levels, uint16_t ilev)
267{
268 vm_pindex_t wrapidx;
269
270 for (; levels[ilev] == FALSE ||
271 vm_radix_slot(*idx, ilev) == (VM_RADIX_COUNT - 1); ilev--)
272 if (ilev == 0)
273 break;
274 KASSERT(ilev > 0 || levels[0],
275 ("%s: levels back-scanning problem", __func__));
276 if (ilev == 0 && vm_radix_slot(*idx, ilev) == (VM_RADIX_COUNT - 1))
277 return (1);
278 wrapidx = *idx;
279 *idx = vm_radix_trimkey(*idx, ilev);
280 *idx += VM_RADIX_UNITLEVEL(ilev);
281 return (*idx < wrapidx);
282}
283
284/*
285 * Adjusts the idx key to the first lower level available, based on a valid
286 * initial level and map of available levels.
287 * Returns a value bigger than 0 to signal that there are not valid levels
288 * available.
289 */
290static __inline int
291vm_radix_declev(vm_pindex_t *idx, boolean_t *levels, uint16_t ilev)
292{
293 vm_pindex_t wrapidx;
294
295 for (; levels[ilev] == FALSE ||
296 vm_radix_slot(*idx, ilev) == 0; ilev--)
297 if (ilev == 0)
298 break;
299 KASSERT(ilev > 0 || levels[0],
300 ("%s: levels back-scanning problem", __func__));
301 if (ilev == 0 && vm_radix_slot(*idx, ilev) == 0)
302 return (1);
303 wrapidx = *idx;
304 *idx = vm_radix_trimkey(*idx, ilev);
305 *idx |= VM_RADIX_UNITLEVEL(ilev) - 1;
306 *idx -= VM_RADIX_UNITLEVEL(ilev);
307 return (*idx > wrapidx);
308}
309
310/*
311 * Internal helper for vm_radix_reclaim_allnodes().
312 * This function is recursive.
313 */
314static void
315vm_radix_reclaim_allnodes_int(struct vm_radix_node *rnode)
316{
317 int slot;
318
319 KASSERT(rnode->rn_count <= VM_RADIX_COUNT,
320 ("vm_radix_reclaim_allnodes_int: bad count in rnode %p", rnode));
321 for (slot = 0; rnode->rn_count != 0; slot++) {
322 if (rnode->rn_child[slot] == NULL)
323 continue;
324 if (!vm_radix_isleaf(rnode->rn_child[slot]))
325 vm_radix_reclaim_allnodes_int(rnode->rn_child[slot]);
326 rnode->rn_child[slot] = NULL;
327 rnode->rn_count--;
328 }
329 vm_radix_node_put(rnode);
330}
331
332#ifdef INVARIANTS
333/*
334 * Radix node zone destructor.
335 */
336static void
337vm_radix_node_zone_dtor(void *mem, int size __unused, void *arg __unused)
338{
339 struct vm_radix_node *rnode;
340 int slot;
341
342 rnode = mem;
343 KASSERT(rnode->rn_count == 0,
344 ("vm_radix_node_put: rnode %p has %d children", rnode,
345 rnode->rn_count));
346 for (slot = 0; slot < VM_RADIX_COUNT; slot++)
347 KASSERT(rnode->rn_child[slot] == NULL,
348 ("vm_radix_node_put: rnode %p has a child", rnode));
349}
350#endif
351
352/*
353 * Radix node zone initializer.
354 */
355static int
356vm_radix_node_zone_init(void *mem, int size __unused, int flags __unused)
357{
358 struct vm_radix_node *rnode;
359
360 rnode = mem;
361 memset(rnode->rn_child, 0, sizeof(rnode->rn_child));
362 return (0);
363}
364
365/*
366 * Pre-allocate intermediate nodes from the UMA slab zone.
367 */
368static void
369vm_radix_prealloc(void *arg __unused)
370{
371
372 if (!uma_zone_reserve_kva(vm_radix_node_zone, cnt.v_page_count))
373 panic("%s: unable to create new zone", __func__);
374 uma_prealloc(vm_radix_node_zone, cnt.v_page_count);
375}
376SYSINIT(vm_radix_prealloc, SI_SUB_KMEM, SI_ORDER_SECOND, vm_radix_prealloc,
377 NULL);
378
379/*
380 * Initialize the UMA slab zone.
381 * Until vm_radix_prealloc() is called, the zone will be served by the
382 * UMA boot-time pre-allocated pool of pages.
383 */
384void
385vm_radix_init(void)
386{
387
388 vm_radix_node_zone = uma_zcreate("RADIX NODE",
389 sizeof(struct vm_radix_node), NULL,
390#ifdef INVARIANTS
391 vm_radix_node_zone_dtor,
392#else
393 NULL,
394#endif
395 vm_radix_node_zone_init, NULL, VM_RADIX_PAD, UMA_ZONE_VM |
396 UMA_ZONE_NOFREE);
397}
398
399/*
400 * Inserts the key-value pair into the trie.
401 * Panics if the key already exists.
402 */
403void
404vm_radix_insert(struct vm_radix *rtree, vm_page_t page)
405{
406 vm_pindex_t index, newind;
407 struct vm_radix_node *parent, *rnode, *tmp;
408 vm_page_t m;
409 int slot;
410 uint16_t clev;
411
412 index = page->pindex;
413
414 /*
415 * The owner of record for root is not really important because it
416 * will never be used.
417 */
418 rnode = vm_radix_getroot(rtree);
419 if (rnode == NULL) {
420 rnode = vm_radix_node_get(0, 1, 0);
421 vm_radix_setroot(rtree, rnode);
422 vm_radix_addpage(rnode, index, 0, page);
423 return;
424 }
425 do {
426 slot = vm_radix_slot(index, rnode->rn_clev);
427 if (vm_radix_isleaf(rnode->rn_child[slot])) {
428 m = vm_radix_topage(rnode->rn_child[slot]);
429 if (m->pindex == index)
430 panic("%s: key %jx is already present",
431 __func__, (uintmax_t)index);
432 clev = vm_radix_keydiff(m->pindex, index);
433 tmp = vm_radix_node_get(vm_radix_trimkey(index,
434 clev - 1), 2, clev);
435 rnode->rn_child[slot] = tmp;
436 vm_radix_addpage(tmp, index, clev, page);
437 vm_radix_addpage(tmp, m->pindex, clev, m);
438 return;
439 }
440 if (rnode->rn_child[slot] == NULL) {
441 rnode->rn_count++;
442 vm_radix_addpage(rnode, index, rnode->rn_clev, page);
443 return;
444 }
445 parent = rnode;
446 rnode = rnode->rn_child[slot];
447 } while (!vm_radix_keybarr(rnode, index));
448
449 /*
450 * A new node is needed because the right insertion level is reached.
451 * Setup the new intermediate node and add the 2 children: the
452 * new object and the older edge.
453 */
454 newind = rnode->rn_owner;
455 clev = vm_radix_keydiff(newind, index);
456 tmp = vm_radix_node_get(vm_radix_trimkey(index, clev - 1), 2,
457 clev);
458 parent->rn_child[slot] = tmp;
459 vm_radix_addpage(tmp, index, clev, page);
460 slot = vm_radix_slot(newind, clev);
461 tmp->rn_child[slot] = rnode;
462}
463
464/*
465 * Returns the value stored at the index. If the index is not present,
466 * NULL is returned.
467 */
468vm_page_t
469vm_radix_lookup(struct vm_radix *rtree, vm_pindex_t index)
470{
471 struct vm_radix_node *rnode;
472 vm_page_t m;
473 int slot;
474
475 rnode = vm_radix_getroot(rtree);
476 while (rnode != NULL) {
477 if (vm_radix_keybarr(rnode, index))
478 return (NULL);
479 slot = vm_radix_slot(index, rnode->rn_clev);
480 rnode = rnode->rn_child[slot];
481 if (vm_radix_isleaf(rnode)) {
482 m = vm_radix_topage(rnode);
483 if (m->pindex == index)
484 return (m);
485 else
486 return (NULL);
487 }
488 }
489 return (NULL);
490}
491
492/*
493 * Look up the nearest entry at a position bigger than or equal to index.
494 */
495vm_page_t
496vm_radix_lookup_ge(struct vm_radix *rtree, vm_pindex_t index)
497{
498 vm_pindex_t inc;
499 vm_page_t m;
500 struct vm_radix_node *child, *rnode;
501 int slot;
502 uint16_t difflev;
503 boolean_t maplevels[VM_RADIX_LIMIT + 1];
504#ifdef INVARIANTS
505 int loops = 0;
506#endif
507
508restart:
509 KASSERT(++loops < 1000, ("%s: too many loops", __func__));
510 for (difflev = 0; difflev < (VM_RADIX_LIMIT + 1); difflev++)
511 maplevels[difflev] = FALSE;
512 rnode = vm_radix_getroot(rtree);
513 while (rnode != NULL) {
514 maplevels[rnode->rn_clev] = TRUE;
515
516 /*
517 * If the keys differ before the current bisection node
518 * the search key might rollback to the earliest
519 * available bisection node, or to the smaller value
520 * in the current domain (if the owner is bigger than the
521 * search key).
522 * The maplevels array records any node has been seen
523 * at a given level. This aids the search for a valid
524 * bisection node.
525 */
526 if (vm_radix_keybarr(rnode, index)) {
527 difflev = vm_radix_keydiff(index, rnode->rn_owner);
528 if (index > rnode->rn_owner) {
529 if (vm_radix_addlev(&index, maplevels,
530 difflev) > 0)
531 break;
532 } else
533 index = vm_radix_trimkey(rnode->rn_owner,
534 difflev);
535 goto restart;
536 }
537 slot = vm_radix_slot(index, rnode->rn_clev);
538 child = rnode->rn_child[slot];
539 if (vm_radix_isleaf(child)) {
540 m = vm_radix_topage(child);
541 if (m->pindex >= index)
542 return (m);
543 } else if (child != NULL)
544 goto descend;
545
546 /*
547 * Look for an available edge or page within the current
548 * bisection node.
549 */
550 if (slot < (VM_RADIX_COUNT - 1)) {
551 inc = VM_RADIX_UNITLEVEL(rnode->rn_clev);
552 index = vm_radix_trimkey(index, rnode->rn_clev);
553 do {
554 index += inc;
555 slot++;
556 child = rnode->rn_child[slot];
557 if (vm_radix_isleaf(child)) {
558 m = vm_radix_topage(child);
559 if (m->pindex >= index)
560 return (m);
561 } else if (child != NULL)
562 goto descend;
563 } while (slot < (VM_RADIX_COUNT - 1));
564 }
565 KASSERT(child == NULL || vm_radix_isleaf(child),
566 ("vm_radix_lookup_ge: child is radix node"));
567
568 /*
569 * If a valid page or edge bigger than the search slot is
570 * found in the traversal, skip to the next higher-level key.
571 */
572 if (rnode->rn_clev == 0 || vm_radix_addlev(&index, maplevels,
573 rnode->rn_clev - 1) > 0)
574 break;
575 goto restart;
576descend:
577 rnode = child;
578 }
579 return (NULL);
580}
581
582/*
583 * Look up the nearest entry at a position less than or equal to index.
584 */
585vm_page_t
586vm_radix_lookup_le(struct vm_radix *rtree, vm_pindex_t index)
587{
588 vm_pindex_t inc;
589 vm_page_t m;
590 struct vm_radix_node *child, *rnode;
591 int slot;
592 uint16_t difflev;
593 boolean_t maplevels[VM_RADIX_LIMIT + 1];
594#ifdef INVARIANTS
595 int loops = 0;
596#endif
597
598restart:
599 KASSERT(++loops < 1000, ("%s: too many loops", __func__));
600 for (difflev = 0; difflev < (VM_RADIX_LIMIT + 1); difflev++)
601 maplevels[difflev] = FALSE;
602 rnode = vm_radix_getroot(rtree);
603 while (rnode != NULL) {
604 maplevels[rnode->rn_clev] = TRUE;
605
606 /*
607 * If the keys differ before the current bisection node
608 * the search key might rollback to the earliest
609 * available bisection node, or to the higher value
610 * in the current domain (if the owner is smaller than the
611 * search key).
612 * The maplevels array records any node has been seen
613 * at a given level. This aids the search for a valid
614 * bisection node.
615 */
616 if (vm_radix_keybarr(rnode, index)) {
617 difflev = vm_radix_keydiff(index, rnode->rn_owner);
618 if (index > rnode->rn_owner) {
619 index = vm_radix_trimkey(rnode->rn_owner,
620 difflev);
621 index |= VM_RADIX_UNITLEVEL(difflev) - 1;
622 } else if (vm_radix_declev(&index, maplevels,
623 difflev) > 0)
624 break;
625 goto restart;
626 }
627 slot = vm_radix_slot(index, rnode->rn_clev);
628 child = rnode->rn_child[slot];
629 if (vm_radix_isleaf(child)) {
630 m = vm_radix_topage(child);
631 if (m->pindex <= index)
632 return (m);
633 } else if (child != NULL)
634 goto descend;
635
636 /*
637 * Look for an available edge or page within the current
638 * bisection node.
639 */
640 if (slot > 0) {
641 inc = VM_RADIX_UNITLEVEL(rnode->rn_clev);
642 index = vm_radix_trimkey(index, rnode->rn_clev);
643 index |= inc - 1;
644 do {
645 index -= inc;
646 slot--;
647 child = rnode->rn_child[slot];
648 if (vm_radix_isleaf(child)) {
649 m = vm_radix_topage(child);
650 if (m->pindex <= index)
651 return (m);
652 } else if (child != NULL)
653 goto descend;
654 } while (slot > 0);
655 }
656 KASSERT(child == NULL || vm_radix_isleaf(child),
657 ("vm_radix_lookup_le: child is radix node"));
658
659 /*
660 * If a valid page or edge smaller than the search slot is
661 * found in the traversal, skip to the next higher-level key.
662 */
663 if (rnode->rn_clev == 0 || vm_radix_declev(&index, maplevels,
664 rnode->rn_clev - 1) > 0)
665 break;
666 goto restart;
667descend:
668 rnode = child;
669 }
670 return (NULL);
671}
672
673/*
674 * Remove the specified index from the tree.
675 * Panics if the key is not present.
676 */
677void
678vm_radix_remove(struct vm_radix *rtree, vm_pindex_t index)
679{
680 struct vm_radix_node *rnode, *parent;
681 vm_page_t m;
682 int i, slot;
683
684 parent = NULL;
685 rnode = vm_radix_getroot(rtree);
686 for (;;) {
687 if (rnode == NULL)
688 panic("vm_radix_remove: impossible to locate the key");
689 slot = vm_radix_slot(index, rnode->rn_clev);
690 if (vm_radix_isleaf(rnode->rn_child[slot])) {
691 m = vm_radix_topage(rnode->rn_child[slot]);
692 if (m->pindex != index)
693 panic("%s: invalid key found", __func__);
694 rnode->rn_child[slot] = NULL;
695 rnode->rn_count--;
696 if (rnode->rn_count > 1)
697 break;
698 if (parent == NULL) {
699 if (rnode->rn_count == 0) {
700 vm_radix_node_put(rnode);
701 vm_radix_setroot(rtree, NULL);
702 }
703 break;
704 }
705 for (i = 0; i < VM_RADIX_COUNT; i++)
706 if (rnode->rn_child[i] != NULL)
707 break;
708 KASSERT(i != VM_RADIX_COUNT,
709 ("%s: invalid node configuration", __func__));
710 slot = vm_radix_slot(index, parent->rn_clev);
711 KASSERT(parent->rn_child[slot] == rnode,
712 ("%s: invalid child value", __func__));
713 parent->rn_child[slot] = rnode->rn_child[i];
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 */
729void
730vm_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 vm_radix_reclaim_allnodes_int(root);
739}
740
741#ifdef DDB
742/*
743 * Show details about the given radix node.
744 */
745DB_SHOW_COMMAND(radixnode, db_show_radixnode)
746{
747 struct vm_radix_node *rnode;
748 int i;
749
750 if (!have_addr)
751 return;
752 rnode = (struct vm_radix_node *)addr;
753 db_printf("radixnode %p, owner %jx, children count %u, level %u:\n",
754 (void *)rnode, (uintmax_t)rnode->rn_owner, rnode->rn_count,
755 rnode->rn_clev);
756 for (i = 0; i < VM_RADIX_COUNT; i++)
757 if (rnode->rn_child[i] != NULL)
758 db_printf("slot: %d, val: %p, page: %p, clev: %d\n",
759 i, (void *)rnode->rn_child[i],
760 vm_radix_isleaf(rnode->rn_child[i]) ?
761 vm_radix_topage(rnode->rn_child[i]) : NULL,
762 rnode->rn_clev);
763}
764#endif /* DDB */
179}
180
181/*
182 * Set the root node for a radix tree.
183 */
184static __inline void
185vm_radix_setroot(struct vm_radix *rtree, struct vm_radix_node *rnode)
186{
187
188 rtree->rt_root = (uintptr_t)rnode;
189}
190
191/*
192 * Returns TRUE if the specified radix node is a leaf and FALSE otherwise.
193 */
194static __inline boolean_t
195vm_radix_isleaf(struct vm_radix_node *rnode)
196{
197
198 return (((uintptr_t)rnode & VM_RADIX_ISLEAF) != 0);
199}
200
201/*
202 * Returns the associated page extracted from rnode.
203 */
204static __inline vm_page_t
205vm_radix_topage(struct vm_radix_node *rnode)
206{
207
208 return ((vm_page_t)((uintptr_t)rnode & ~VM_RADIX_FLAGS));
209}
210
211/*
212 * Adds the page as a child of the provided node.
213 */
214static __inline void
215vm_radix_addpage(struct vm_radix_node *rnode, vm_pindex_t index, uint16_t clev,
216 vm_page_t page)
217{
218 int slot;
219
220 slot = vm_radix_slot(index, clev);
221 rnode->rn_child[slot] = (void *)((uintptr_t)page | VM_RADIX_ISLEAF);
222}
223
224/*
225 * Returns the slot where two keys differ.
226 * It cannot accept 2 equal keys.
227 */
228static __inline uint16_t
229vm_radix_keydiff(vm_pindex_t index1, vm_pindex_t index2)
230{
231 uint16_t clev;
232
233 KASSERT(index1 != index2, ("%s: passing the same key value %jx",
234 __func__, (uintmax_t)index1));
235
236 index1 ^= index2;
237 for (clev = 0; clev <= VM_RADIX_LIMIT ; clev++)
238 if (vm_radix_slot(index1, clev))
239 return (clev);
240 panic("%s: cannot reach this point", __func__);
241 return (0);
242}
243
244/*
245 * Returns TRUE if it can be determined that key does not belong to the
246 * specified rnode. Otherwise, returns FALSE.
247 */
248static __inline boolean_t
249vm_radix_keybarr(struct vm_radix_node *rnode, vm_pindex_t idx)
250{
251
252 if (rnode->rn_clev > 0) {
253 idx = vm_radix_trimkey(idx, rnode->rn_clev - 1);
254 return (idx != rnode->rn_owner);
255 }
256 return (FALSE);
257}
258
259/*
260 * Adjusts the idx key to the first upper level available, based on a valid
261 * initial level and map of available levels.
262 * Returns a value bigger than 0 to signal that there are not valid levels
263 * available.
264 */
265static __inline int
266vm_radix_addlev(vm_pindex_t *idx, boolean_t *levels, uint16_t ilev)
267{
268 vm_pindex_t wrapidx;
269
270 for (; levels[ilev] == FALSE ||
271 vm_radix_slot(*idx, ilev) == (VM_RADIX_COUNT - 1); ilev--)
272 if (ilev == 0)
273 break;
274 KASSERT(ilev > 0 || levels[0],
275 ("%s: levels back-scanning problem", __func__));
276 if (ilev == 0 && vm_radix_slot(*idx, ilev) == (VM_RADIX_COUNT - 1))
277 return (1);
278 wrapidx = *idx;
279 *idx = vm_radix_trimkey(*idx, ilev);
280 *idx += VM_RADIX_UNITLEVEL(ilev);
281 return (*idx < wrapidx);
282}
283
284/*
285 * Adjusts the idx key to the first lower level available, based on a valid
286 * initial level and map of available levels.
287 * Returns a value bigger than 0 to signal that there are not valid levels
288 * available.
289 */
290static __inline int
291vm_radix_declev(vm_pindex_t *idx, boolean_t *levels, uint16_t ilev)
292{
293 vm_pindex_t wrapidx;
294
295 for (; levels[ilev] == FALSE ||
296 vm_radix_slot(*idx, ilev) == 0; ilev--)
297 if (ilev == 0)
298 break;
299 KASSERT(ilev > 0 || levels[0],
300 ("%s: levels back-scanning problem", __func__));
301 if (ilev == 0 && vm_radix_slot(*idx, ilev) == 0)
302 return (1);
303 wrapidx = *idx;
304 *idx = vm_radix_trimkey(*idx, ilev);
305 *idx |= VM_RADIX_UNITLEVEL(ilev) - 1;
306 *idx -= VM_RADIX_UNITLEVEL(ilev);
307 return (*idx > wrapidx);
308}
309
310/*
311 * Internal helper for vm_radix_reclaim_allnodes().
312 * This function is recursive.
313 */
314static void
315vm_radix_reclaim_allnodes_int(struct vm_radix_node *rnode)
316{
317 int slot;
318
319 KASSERT(rnode->rn_count <= VM_RADIX_COUNT,
320 ("vm_radix_reclaim_allnodes_int: bad count in rnode %p", rnode));
321 for (slot = 0; rnode->rn_count != 0; slot++) {
322 if (rnode->rn_child[slot] == NULL)
323 continue;
324 if (!vm_radix_isleaf(rnode->rn_child[slot]))
325 vm_radix_reclaim_allnodes_int(rnode->rn_child[slot]);
326 rnode->rn_child[slot] = NULL;
327 rnode->rn_count--;
328 }
329 vm_radix_node_put(rnode);
330}
331
332#ifdef INVARIANTS
333/*
334 * Radix node zone destructor.
335 */
336static void
337vm_radix_node_zone_dtor(void *mem, int size __unused, void *arg __unused)
338{
339 struct vm_radix_node *rnode;
340 int slot;
341
342 rnode = mem;
343 KASSERT(rnode->rn_count == 0,
344 ("vm_radix_node_put: rnode %p has %d children", rnode,
345 rnode->rn_count));
346 for (slot = 0; slot < VM_RADIX_COUNT; slot++)
347 KASSERT(rnode->rn_child[slot] == NULL,
348 ("vm_radix_node_put: rnode %p has a child", rnode));
349}
350#endif
351
352/*
353 * Radix node zone initializer.
354 */
355static int
356vm_radix_node_zone_init(void *mem, int size __unused, int flags __unused)
357{
358 struct vm_radix_node *rnode;
359
360 rnode = mem;
361 memset(rnode->rn_child, 0, sizeof(rnode->rn_child));
362 return (0);
363}
364
365/*
366 * Pre-allocate intermediate nodes from the UMA slab zone.
367 */
368static void
369vm_radix_prealloc(void *arg __unused)
370{
371
372 if (!uma_zone_reserve_kva(vm_radix_node_zone, cnt.v_page_count))
373 panic("%s: unable to create new zone", __func__);
374 uma_prealloc(vm_radix_node_zone, cnt.v_page_count);
375}
376SYSINIT(vm_radix_prealloc, SI_SUB_KMEM, SI_ORDER_SECOND, vm_radix_prealloc,
377 NULL);
378
379/*
380 * Initialize the UMA slab zone.
381 * Until vm_radix_prealloc() is called, the zone will be served by the
382 * UMA boot-time pre-allocated pool of pages.
383 */
384void
385vm_radix_init(void)
386{
387
388 vm_radix_node_zone = uma_zcreate("RADIX NODE",
389 sizeof(struct vm_radix_node), NULL,
390#ifdef INVARIANTS
391 vm_radix_node_zone_dtor,
392#else
393 NULL,
394#endif
395 vm_radix_node_zone_init, NULL, VM_RADIX_PAD, UMA_ZONE_VM |
396 UMA_ZONE_NOFREE);
397}
398
399/*
400 * Inserts the key-value pair into the trie.
401 * Panics if the key already exists.
402 */
403void
404vm_radix_insert(struct vm_radix *rtree, vm_page_t page)
405{
406 vm_pindex_t index, newind;
407 struct vm_radix_node *parent, *rnode, *tmp;
408 vm_page_t m;
409 int slot;
410 uint16_t clev;
411
412 index = page->pindex;
413
414 /*
415 * The owner of record for root is not really important because it
416 * will never be used.
417 */
418 rnode = vm_radix_getroot(rtree);
419 if (rnode == NULL) {
420 rnode = vm_radix_node_get(0, 1, 0);
421 vm_radix_setroot(rtree, rnode);
422 vm_radix_addpage(rnode, index, 0, page);
423 return;
424 }
425 do {
426 slot = vm_radix_slot(index, rnode->rn_clev);
427 if (vm_radix_isleaf(rnode->rn_child[slot])) {
428 m = vm_radix_topage(rnode->rn_child[slot]);
429 if (m->pindex == index)
430 panic("%s: key %jx is already present",
431 __func__, (uintmax_t)index);
432 clev = vm_radix_keydiff(m->pindex, index);
433 tmp = vm_radix_node_get(vm_radix_trimkey(index,
434 clev - 1), 2, clev);
435 rnode->rn_child[slot] = tmp;
436 vm_radix_addpage(tmp, index, clev, page);
437 vm_radix_addpage(tmp, m->pindex, clev, m);
438 return;
439 }
440 if (rnode->rn_child[slot] == NULL) {
441 rnode->rn_count++;
442 vm_radix_addpage(rnode, index, rnode->rn_clev, page);
443 return;
444 }
445 parent = rnode;
446 rnode = rnode->rn_child[slot];
447 } while (!vm_radix_keybarr(rnode, index));
448
449 /*
450 * A new node is needed because the right insertion level is reached.
451 * Setup the new intermediate node and add the 2 children: the
452 * new object and the older edge.
453 */
454 newind = rnode->rn_owner;
455 clev = vm_radix_keydiff(newind, index);
456 tmp = vm_radix_node_get(vm_radix_trimkey(index, clev - 1), 2,
457 clev);
458 parent->rn_child[slot] = tmp;
459 vm_radix_addpage(tmp, index, clev, page);
460 slot = vm_radix_slot(newind, clev);
461 tmp->rn_child[slot] = rnode;
462}
463
464/*
465 * Returns the value stored at the index. If the index is not present,
466 * NULL is returned.
467 */
468vm_page_t
469vm_radix_lookup(struct vm_radix *rtree, vm_pindex_t index)
470{
471 struct vm_radix_node *rnode;
472 vm_page_t m;
473 int slot;
474
475 rnode = vm_radix_getroot(rtree);
476 while (rnode != NULL) {
477 if (vm_radix_keybarr(rnode, index))
478 return (NULL);
479 slot = vm_radix_slot(index, rnode->rn_clev);
480 rnode = rnode->rn_child[slot];
481 if (vm_radix_isleaf(rnode)) {
482 m = vm_radix_topage(rnode);
483 if (m->pindex == index)
484 return (m);
485 else
486 return (NULL);
487 }
488 }
489 return (NULL);
490}
491
492/*
493 * Look up the nearest entry at a position bigger than or equal to index.
494 */
495vm_page_t
496vm_radix_lookup_ge(struct vm_radix *rtree, vm_pindex_t index)
497{
498 vm_pindex_t inc;
499 vm_page_t m;
500 struct vm_radix_node *child, *rnode;
501 int slot;
502 uint16_t difflev;
503 boolean_t maplevels[VM_RADIX_LIMIT + 1];
504#ifdef INVARIANTS
505 int loops = 0;
506#endif
507
508restart:
509 KASSERT(++loops < 1000, ("%s: too many loops", __func__));
510 for (difflev = 0; difflev < (VM_RADIX_LIMIT + 1); difflev++)
511 maplevels[difflev] = FALSE;
512 rnode = vm_radix_getroot(rtree);
513 while (rnode != NULL) {
514 maplevels[rnode->rn_clev] = TRUE;
515
516 /*
517 * If the keys differ before the current bisection node
518 * the search key might rollback to the earliest
519 * available bisection node, or to the smaller value
520 * in the current domain (if the owner is bigger than the
521 * search key).
522 * The maplevels array records any node has been seen
523 * at a given level. This aids the search for a valid
524 * bisection node.
525 */
526 if (vm_radix_keybarr(rnode, index)) {
527 difflev = vm_radix_keydiff(index, rnode->rn_owner);
528 if (index > rnode->rn_owner) {
529 if (vm_radix_addlev(&index, maplevels,
530 difflev) > 0)
531 break;
532 } else
533 index = vm_radix_trimkey(rnode->rn_owner,
534 difflev);
535 goto restart;
536 }
537 slot = vm_radix_slot(index, rnode->rn_clev);
538 child = rnode->rn_child[slot];
539 if (vm_radix_isleaf(child)) {
540 m = vm_radix_topage(child);
541 if (m->pindex >= index)
542 return (m);
543 } else if (child != NULL)
544 goto descend;
545
546 /*
547 * Look for an available edge or page within the current
548 * bisection node.
549 */
550 if (slot < (VM_RADIX_COUNT - 1)) {
551 inc = VM_RADIX_UNITLEVEL(rnode->rn_clev);
552 index = vm_radix_trimkey(index, rnode->rn_clev);
553 do {
554 index += inc;
555 slot++;
556 child = rnode->rn_child[slot];
557 if (vm_radix_isleaf(child)) {
558 m = vm_radix_topage(child);
559 if (m->pindex >= index)
560 return (m);
561 } else if (child != NULL)
562 goto descend;
563 } while (slot < (VM_RADIX_COUNT - 1));
564 }
565 KASSERT(child == NULL || vm_radix_isleaf(child),
566 ("vm_radix_lookup_ge: child is radix node"));
567
568 /*
569 * If a valid page or edge bigger than the search slot is
570 * found in the traversal, skip to the next higher-level key.
571 */
572 if (rnode->rn_clev == 0 || vm_radix_addlev(&index, maplevels,
573 rnode->rn_clev - 1) > 0)
574 break;
575 goto restart;
576descend:
577 rnode = child;
578 }
579 return (NULL);
580}
581
582/*
583 * Look up the nearest entry at a position less than or equal to index.
584 */
585vm_page_t
586vm_radix_lookup_le(struct vm_radix *rtree, vm_pindex_t index)
587{
588 vm_pindex_t inc;
589 vm_page_t m;
590 struct vm_radix_node *child, *rnode;
591 int slot;
592 uint16_t difflev;
593 boolean_t maplevels[VM_RADIX_LIMIT + 1];
594#ifdef INVARIANTS
595 int loops = 0;
596#endif
597
598restart:
599 KASSERT(++loops < 1000, ("%s: too many loops", __func__));
600 for (difflev = 0; difflev < (VM_RADIX_LIMIT + 1); difflev++)
601 maplevels[difflev] = FALSE;
602 rnode = vm_radix_getroot(rtree);
603 while (rnode != NULL) {
604 maplevels[rnode->rn_clev] = TRUE;
605
606 /*
607 * If the keys differ before the current bisection node
608 * the search key might rollback to the earliest
609 * available bisection node, or to the higher value
610 * in the current domain (if the owner is smaller than the
611 * search key).
612 * The maplevels array records any node has been seen
613 * at a given level. This aids the search for a valid
614 * bisection node.
615 */
616 if (vm_radix_keybarr(rnode, index)) {
617 difflev = vm_radix_keydiff(index, rnode->rn_owner);
618 if (index > rnode->rn_owner) {
619 index = vm_radix_trimkey(rnode->rn_owner,
620 difflev);
621 index |= VM_RADIX_UNITLEVEL(difflev) - 1;
622 } else if (vm_radix_declev(&index, maplevels,
623 difflev) > 0)
624 break;
625 goto restart;
626 }
627 slot = vm_radix_slot(index, rnode->rn_clev);
628 child = rnode->rn_child[slot];
629 if (vm_radix_isleaf(child)) {
630 m = vm_radix_topage(child);
631 if (m->pindex <= index)
632 return (m);
633 } else if (child != NULL)
634 goto descend;
635
636 /*
637 * Look for an available edge or page within the current
638 * bisection node.
639 */
640 if (slot > 0) {
641 inc = VM_RADIX_UNITLEVEL(rnode->rn_clev);
642 index = vm_radix_trimkey(index, rnode->rn_clev);
643 index |= inc - 1;
644 do {
645 index -= inc;
646 slot--;
647 child = rnode->rn_child[slot];
648 if (vm_radix_isleaf(child)) {
649 m = vm_radix_topage(child);
650 if (m->pindex <= index)
651 return (m);
652 } else if (child != NULL)
653 goto descend;
654 } while (slot > 0);
655 }
656 KASSERT(child == NULL || vm_radix_isleaf(child),
657 ("vm_radix_lookup_le: child is radix node"));
658
659 /*
660 * If a valid page or edge smaller than the search slot is
661 * found in the traversal, skip to the next higher-level key.
662 */
663 if (rnode->rn_clev == 0 || vm_radix_declev(&index, maplevels,
664 rnode->rn_clev - 1) > 0)
665 break;
666 goto restart;
667descend:
668 rnode = child;
669 }
670 return (NULL);
671}
672
673/*
674 * Remove the specified index from the tree.
675 * Panics if the key is not present.
676 */
677void
678vm_radix_remove(struct vm_radix *rtree, vm_pindex_t index)
679{
680 struct vm_radix_node *rnode, *parent;
681 vm_page_t m;
682 int i, slot;
683
684 parent = NULL;
685 rnode = vm_radix_getroot(rtree);
686 for (;;) {
687 if (rnode == NULL)
688 panic("vm_radix_remove: impossible to locate the key");
689 slot = vm_radix_slot(index, rnode->rn_clev);
690 if (vm_radix_isleaf(rnode->rn_child[slot])) {
691 m = vm_radix_topage(rnode->rn_child[slot]);
692 if (m->pindex != index)
693 panic("%s: invalid key found", __func__);
694 rnode->rn_child[slot] = NULL;
695 rnode->rn_count--;
696 if (rnode->rn_count > 1)
697 break;
698 if (parent == NULL) {
699 if (rnode->rn_count == 0) {
700 vm_radix_node_put(rnode);
701 vm_radix_setroot(rtree, NULL);
702 }
703 break;
704 }
705 for (i = 0; i < VM_RADIX_COUNT; i++)
706 if (rnode->rn_child[i] != NULL)
707 break;
708 KASSERT(i != VM_RADIX_COUNT,
709 ("%s: invalid node configuration", __func__));
710 slot = vm_radix_slot(index, parent->rn_clev);
711 KASSERT(parent->rn_child[slot] == rnode,
712 ("%s: invalid child value", __func__));
713 parent->rn_child[slot] = rnode->rn_child[i];
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 */
729void
730vm_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 vm_radix_reclaim_allnodes_int(root);
739}
740
741#ifdef DDB
742/*
743 * Show details about the given radix node.
744 */
745DB_SHOW_COMMAND(radixnode, db_show_radixnode)
746{
747 struct vm_radix_node *rnode;
748 int i;
749
750 if (!have_addr)
751 return;
752 rnode = (struct vm_radix_node *)addr;
753 db_printf("radixnode %p, owner %jx, children count %u, level %u:\n",
754 (void *)rnode, (uintmax_t)rnode->rn_owner, rnode->rn_count,
755 rnode->rn_clev);
756 for (i = 0; i < VM_RADIX_COUNT; i++)
757 if (rnode->rn_child[i] != NULL)
758 db_printf("slot: %d, val: %p, page: %p, clev: %d\n",
759 i, (void *)rnode->rn_child[i],
760 vm_radix_isleaf(rnode->rn_child[i]) ?
761 vm_radix_topage(rnode->rn_child[i]) : NULL,
762 rnode->rn_clev);
763}
764#endif /* DDB */