kernel - Fix a few edge cases in subr_blist.c
[dragonfly.git] / sys / kern / subr_blist.c
CommitLineData
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1/*
2 * BLIST.C - Bitmap allocator/deallocator, using a radix tree with hinting
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3 *
4 * Copyright (c) 1998,2004 The DragonFly Project. All rights reserved.
5 *
6 * This code is derived from software contributed to The DragonFly Project
7 * by Matthew Dillon <dillon@backplane.com>
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
18 * distribution.
19 * 3. Neither the name of The DragonFly Project nor the names of its
20 * contributors may be used to endorse or promote products derived
21 * from this software without specific, prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
26 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
27 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
28 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
29 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
30 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
31 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
32 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
33 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
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36 *
37 * This module implements a general bitmap allocator/deallocator. The
38 * allocator eats around 2 bits per 'block'. The module does not
39 * try to interpret the meaning of a 'block' other then to return
40 * SWAPBLK_NONE on an allocation failure.
41 *
42 * A radix tree is used to maintain the bitmap. Two radix constants are
43 * involved: One for the bitmaps contained in the leaf nodes (typically
44 * 32), and one for the meta nodes (typically 16). Both meta and leaf
45 * nodes have a hint field. This field gives us a hint as to the largest
46 * free contiguous range of blocks under the node. It may contain a
47 * value that is too high, but will never contain a value that is too
48 * low. When the radix tree is searched, allocation failures in subtrees
49 * update the hint.
50 *
51 * The radix tree also implements two collapsed states for meta nodes:
52 * the ALL-ALLOCATED state and the ALL-FREE state. If a meta node is
53 * in either of these two states, all information contained underneath
54 * the node is considered stale. These states are used to optimize
55 * allocation and freeing operations.
56 *
57 * The hinting greatly increases code efficiency for allocations while
58 * the general radix structure optimizes both allocations and frees. The
59 * radix tree should be able to operate well no matter how much
60 * fragmentation there is and no matter how large a bitmap is used.
61 *
62 * Unlike the rlist code, the blist code wires all necessary memory at
63 * creation time. Neither allocations nor frees require interaction with
64 * the memory subsystem. In contrast, the rlist code may allocate memory
65 * on an rlist_free() call. The non-blocking features of the blist code
66 * are used to great advantage in the swap code (vm/nswap_pager.c). The
67 * rlist code uses a little less overall memory then the blist code (but
68 * due to swap interleaving not all that much less), but the blist code
69 * scales much, much better.
70 *
71 * LAYOUT: The radix tree is layed out recursively using a
72 * linear array. Each meta node is immediately followed (layed out
73 * sequentially in memory) by BLIST_META_RADIX lower level nodes. This
74 * is a recursive structure but one that can be easily scanned through
75 * a very simple 'skip' calculation. In order to support large radixes,
76 * portions of the tree may reside outside our memory allocation. We
77 * handle this with an early-termination optimization (when bighint is
78 * set to -1) on the scan. The memory allocation is only large enough
79 * to cover the number of blocks requested at creation time even if it
80 * must be encompassed in larger root-node radix.
81 *
79634a66 82 * NOTE: The allocator cannot currently allocate more then
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83 * BLIST_BMAP_RADIX blocks per call. It will panic with 'allocation too
84 * large' if you try. This is an area that could use improvement. The
85 * radix is large enough that this restriction does not effect the swap
86 * system, though. Currently only the allocation code is effected by
87 * this algorithmic unfeature. The freeing code can handle arbitrary
88 * ranges.
89 *
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90 * NOTE: The radix may exceed 32 bits in order to support up to 2^31
91 * blocks. The first divison will drop the radix down and fit
92 * it within a signed 32 bit integer.
93 *
984263bc 94 * This code can be compiled stand-alone for debugging.
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95 */
96
97#ifdef _KERNEL
98
99#include <sys/param.h>
100#include <sys/systm.h>
101#include <sys/lock.h>
102#include <sys/kernel.h>
103#include <sys/blist.h>
104#include <sys/malloc.h>
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105
106#else
107
108#ifndef BLIST_NO_DEBUG
109#define BLIST_DEBUG
110#endif
111
35d5bbd3 112#define SWAPBLK_NONE ((swblk_t)-1)
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113
114#include <sys/types.h>
115#include <stdio.h>
116#include <string.h>
117#include <stdlib.h>
118#include <stdarg.h>
119
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120#define kmalloc(a,b,c) malloc(a)
121#define kfree(a,b) free(a)
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122#define kprintf printf
123#define KKASSERT(exp)
984263bc 124
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125#include <sys/blist.h>
126
127void panic(const char *ctl, ...);
128
129#endif
130
131/*
132 * static support functions
133 */
134
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135static swblk_t blst_leaf_alloc(blmeta_t *scan, swblk_t blk, int count);
136static swblk_t blst_meta_alloc(blmeta_t *scan, swblk_t blk,
79634a66 137 swblk_t count, int64_t radix, int skip);
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138static void blst_leaf_free(blmeta_t *scan, swblk_t relblk, int count);
139static void blst_meta_free(blmeta_t *scan, swblk_t freeBlk, swblk_t count,
79634a66 140 int64_t radix, int skip, swblk_t blk);
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141static swblk_t blst_leaf_fill(blmeta_t *scan, swblk_t blk, int count);
142static swblk_t blst_meta_fill(blmeta_t *scan, swblk_t fillBlk, swblk_t count,
143 int64_t radix, int skip, swblk_t blk);
79634a66 144static void blst_copy(blmeta_t *scan, swblk_t blk, int64_t radix,
35d5bbd3 145 swblk_t skip, blist_t dest, swblk_t count);
79634a66 146static swblk_t blst_radix_init(blmeta_t *scan, int64_t radix,
35d5bbd3 147 int skip, swblk_t count);
984263bc 148#ifndef _KERNEL
35d5bbd3 149static void blst_radix_print(blmeta_t *scan, swblk_t blk,
79634a66 150 int64_t radix, int skip, int tab);
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151#endif
152
153#ifdef _KERNEL
154static MALLOC_DEFINE(M_SWAP, "SWAP", "Swap space");
155#endif
156
157/*
158 * blist_create() - create a blist capable of handling up to the specified
159 * number of blocks
160 *
161 * blocks must be greater then 0
162 *
163 * The smallest blist consists of a single leaf node capable of
164 * managing BLIST_BMAP_RADIX blocks.
165 */
166
167blist_t
35d5bbd3 168blist_create(swblk_t blocks)
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169{
170 blist_t bl;
79634a66 171 int64_t radix;
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172 int skip = 0;
173
174 /*
175 * Calculate radix and skip field used for scanning.
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176 *
177 * Radix can exceed 32 bits even if swblk_t is limited to 32 bits.
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178 */
179 radix = BLIST_BMAP_RADIX;
180
181 while (radix < blocks) {
182 radix *= BLIST_META_RADIX;
183 skip = (skip + 1) * BLIST_META_RADIX;
79634a66 184 KKASSERT(skip > 0);
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185 }
186
0c374e73 187 bl = kmalloc(sizeof(struct blist), M_SWAP, M_WAITOK | M_ZERO);
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188
189 bl->bl_blocks = blocks;
190 bl->bl_radix = radix;
191 bl->bl_skip = skip;
192 bl->bl_rootblks = 1 +
193 blst_radix_init(NULL, bl->bl_radix, bl->bl_skip, blocks);
efda3bd0 194 bl->bl_root = kmalloc(sizeof(blmeta_t) * bl->bl_rootblks, M_SWAP, M_WAITOK);
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195
196#if defined(BLIST_DEBUG)
6ea70f76 197 kprintf(
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198 "BLIST representing %d blocks (%d MB of swap)"
199 ", requiring %dK of ram\n",
200 bl->bl_blocks,
201 bl->bl_blocks * 4 / 1024,
202 (bl->bl_rootblks * sizeof(blmeta_t) + 1023) / 1024
203 );
6ea70f76 204 kprintf("BLIST raw radix tree contains %d records\n", bl->bl_rootblks);
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205#endif
206 blst_radix_init(bl->bl_root, bl->bl_radix, bl->bl_skip, blocks);
207
208 return(bl);
209}
210
211void
212blist_destroy(blist_t bl)
213{
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214 kfree(bl->bl_root, M_SWAP);
215 kfree(bl, M_SWAP);
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216}
217
218/*
219 * blist_alloc() - reserve space in the block bitmap. Return the base
220 * of a contiguous region or SWAPBLK_NONE if space could
221 * not be allocated.
222 */
223
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224swblk_t
225blist_alloc(blist_t bl, swblk_t count)
984263bc 226{
35d5bbd3 227 swblk_t blk = SWAPBLK_NONE;
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228
229 if (bl) {
230 if (bl->bl_radix == BLIST_BMAP_RADIX)
231 blk = blst_leaf_alloc(bl->bl_root, 0, count);
232 else
233 blk = blst_meta_alloc(bl->bl_root, 0, count, bl->bl_radix, bl->bl_skip);
234 if (blk != SWAPBLK_NONE)
235 bl->bl_free -= count;
236 }
237 return(blk);
238}
239
240/*
241 * blist_free() - free up space in the block bitmap. Return the base
242 * of a contiguous region. Panic if an inconsistancy is
243 * found.
244 */
245
246void
35d5bbd3 247blist_free(blist_t bl, swblk_t blkno, swblk_t count)
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248{
249 if (bl) {
250 if (bl->bl_radix == BLIST_BMAP_RADIX)
251 blst_leaf_free(bl->bl_root, blkno, count);
252 else
253 blst_meta_free(bl->bl_root, blkno, count, bl->bl_radix, bl->bl_skip, 0);
254 bl->bl_free += count;
255 }
256}
257
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258/*
259 * blist_fill() - mark a region in the block bitmap as off-limits
260 * to the allocator (i.e. allocate it), ignoring any
261 * existing allocations. Return the number of blocks
262 * actually filled that were free before the call.
263 */
264
265swblk_t
266blist_fill(blist_t bl, swblk_t blkno, swblk_t count)
267{
268 swblk_t filled;
269
270 if (bl) {
271 if (bl->bl_radix == BLIST_BMAP_RADIX) {
272 filled = blst_leaf_fill(bl->bl_root, blkno, count);
273 } else {
274 filled = blst_meta_fill(bl->bl_root, blkno, count,
275 bl->bl_radix, bl->bl_skip, 0);
276 }
277 bl->bl_free -= filled;
278 return (filled);
279 } else {
280 return 0;
281 }
282}
283
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284/*
285 * blist_resize() - resize an existing radix tree to handle the
286 * specified number of blocks. This will reallocate
287 * the tree and transfer the previous bitmap to the new
288 * one. When extending the tree you can specify whether
289 * the new blocks are to left allocated or freed.
290 */
291
292void
35d5bbd3 293blist_resize(blist_t *pbl, swblk_t count, int freenew)
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294{
295 blist_t newbl = blist_create(count);
296 blist_t save = *pbl;
297
298 *pbl = newbl;
299 if (count > save->bl_blocks)
300 count = save->bl_blocks;
301 blst_copy(save->bl_root, 0, save->bl_radix, save->bl_skip, newbl, count);
302
303 /*
304 * If resizing upwards, should we free the new space or not?
305 */
306 if (freenew && count < newbl->bl_blocks) {
307 blist_free(newbl, count, newbl->bl_blocks - count);
308 }
309 blist_destroy(save);
310}
311
312#ifdef BLIST_DEBUG
313
314/*
315 * blist_print() - dump radix tree
316 */
317
318void
319blist_print(blist_t bl)
320{
6ea70f76 321 kprintf("BLIST {\n");
984263bc 322 blst_radix_print(bl->bl_root, 0, bl->bl_radix, bl->bl_skip, 4);
6ea70f76 323 kprintf("}\n");
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324}
325
326#endif
327
328/************************************************************************
329 * ALLOCATION SUPPORT FUNCTIONS *
330 ************************************************************************
331 *
332 * These support functions do all the actual work. They may seem
333 * rather longish, but that's because I've commented them up. The
334 * actual code is straight forward.
335 *
336 */
337
338/*
339 * blist_leaf_alloc() - allocate at a leaf in the radix tree (a bitmap).
340 *
341 * This is the core of the allocator and is optimized for the 1 block
342 * and the BLIST_BMAP_RADIX block allocation cases. Other cases are
343 * somewhat slower. The 1 block allocation case is log2 and extremely
344 * quick.
345 */
346
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347static swblk_t
348blst_leaf_alloc(blmeta_t *scan, swblk_t blk, int count)
349{
350 u_swblk_t orig = scan->u.bmu_bitmap;
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351
352 if (orig == 0) {
353 /*
354 * Optimize bitmap all-allocated case. Also, count = 1
355 * case assumes at least 1 bit is free in the bitmap, so
356 * we have to take care of this case here.
357 */
358 scan->bm_bighint = 0;
359 return(SWAPBLK_NONE);
360 }
361 if (count == 1) {
362 /*
363 * Optimized code to allocate one bit out of the bitmap
364 */
35d5bbd3 365 u_swblk_t mask;
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366 int j = BLIST_BMAP_RADIX/2;
367 int r = 0;
368
35d5bbd3 369 mask = (u_swblk_t)-1 >> (BLIST_BMAP_RADIX/2);
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370
371 while (j) {
372 if ((orig & mask) == 0) {
373 r += j;
374 orig >>= j;
375 }
376 j >>= 1;
377 mask >>= j;
378 }
379 scan->u.bmu_bitmap &= ~(1 << r);
380 return(blk + r);
381 }
382 if (count <= BLIST_BMAP_RADIX) {
383 /*
384 * non-optimized code to allocate N bits out of the bitmap.
385 * The more bits, the faster the code runs. It will run
386 * the slowest allocating 2 bits, but since there aren't any
387 * memory ops in the core loop (or shouldn't be, anyway),
388 * you probably won't notice the difference.
389 */
390 int j;
391 int n = BLIST_BMAP_RADIX - count;
35d5bbd3 392 u_swblk_t mask;
984263bc 393
35d5bbd3 394 mask = (u_swblk_t)-1 >> n;
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395
396 for (j = 0; j <= n; ++j) {
397 if ((orig & mask) == mask) {
398 scan->u.bmu_bitmap &= ~mask;
399 return(blk + j);
400 }
401 mask = (mask << 1);
402 }
403 }
404 /*
405 * We couldn't allocate count in this subtree, update bighint.
406 */
407 scan->bm_bighint = count - 1;
408 return(SWAPBLK_NONE);
409}
410
411/*
412 * blist_meta_alloc() - allocate at a meta in the radix tree.
413 *
414 * Attempt to allocate at a meta node. If we can't, we update
415 * bighint and return a failure. Updating bighint optimize future
416 * calls that hit this node. We have to check for our collapse cases
417 * and we have a few optimizations strewn in as well.
418 */
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419static swblk_t
420blst_meta_alloc(blmeta_t *scan, swblk_t blk, swblk_t count,
79634a66 421 int64_t radix, int skip)
35d5bbd3 422{
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423 int i;
424 int next_skip = ((u_int)skip / BLIST_META_RADIX);
425
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426 /*
427 * ALL-ALLOCATED special case
428 */
984263bc 429 if (scan->u.bmu_avail == 0) {
3cd891f0 430 scan->bm_bighint = 0;
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431 return(SWAPBLK_NONE);
432 }
433
79634a66 434 /*
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435 * ALL-FREE special case, initialize uninitialized
436 * sublevel.
437 *
438 * NOTE: radix may exceed 32 bits until first division.
79634a66 439 */
984263bc 440 if (scan->u.bmu_avail == radix) {
3cd891f0 441 scan->bm_bighint = radix;
984263bc 442
3cd891f0 443 radix /= BLIST_META_RADIX;
984263bc 444 for (i = 1; i <= skip; i += next_skip) {
35d5bbd3 445 if (scan[i].bm_bighint == (swblk_t)-1)
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446 break;
447 if (next_skip == 1) {
35d5bbd3 448 scan[i].u.bmu_bitmap = (u_swblk_t)-1;
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449 scan[i].bm_bighint = BLIST_BMAP_RADIX;
450 } else {
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451 scan[i].bm_bighint = (swblk_t)radix;
452 scan[i].u.bmu_avail = (swblk_t)radix;
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453 }
454 }
455 } else {
456 radix /= BLIST_META_RADIX;
457 }
458
459 for (i = 1; i <= skip; i += next_skip) {
460 if (count <= scan[i].bm_bighint) {
461 /*
462 * count fits in object
463 */
35d5bbd3 464 swblk_t r;
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465 if (next_skip == 1) {
466 r = blst_leaf_alloc(&scan[i], blk, count);
467 } else {
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468 r = blst_meta_alloc(&scan[i], blk, count,
469 radix, next_skip - 1);
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470 }
471 if (r != SWAPBLK_NONE) {
472 scan->u.bmu_avail -= count;
473 if (scan->bm_bighint > scan->u.bmu_avail)
474 scan->bm_bighint = scan->u.bmu_avail;
475 return(r);
476 }
3cd891f0 477 /* bighint was updated by recursion */
35d5bbd3 478 } else if (scan[i].bm_bighint == (swblk_t)-1) {
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479 /*
480 * Terminator
481 */
482 break;
79634a66 483 } else if (count > (swblk_t)radix) {
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484 /*
485 * count does not fit in object even if it were
486 * complete free.
487 */
488 panic("blist_meta_alloc: allocation too large");
489 }
79634a66 490 blk += (swblk_t)radix;
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491 }
492
493 /*
494 * We couldn't allocate count in this subtree, update bighint.
495 */
496 if (scan->bm_bighint >= count)
497 scan->bm_bighint = count - 1;
498 return(SWAPBLK_NONE);
499}
500
501/*
502 * BLST_LEAF_FREE() - free allocated block from leaf bitmap
984263bc 503 */
984263bc 504static void
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505blst_leaf_free(blmeta_t *scan, swblk_t blk, int count)
506{
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507 /*
508 * free some data in this bitmap
509 *
510 * e.g.
511 * 0000111111111110000
512 * \_________/\__/
513 * v n
514 */
515 int n = blk & (BLIST_BMAP_RADIX - 1);
35d5bbd3 516 u_swblk_t mask;
984263bc 517
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518 mask = ((u_swblk_t)-1 << n) &
519 ((u_swblk_t)-1 >> (BLIST_BMAP_RADIX - count - n));
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520
521 if (scan->u.bmu_bitmap & mask)
522 panic("blst_radix_free: freeing free block");
523 scan->u.bmu_bitmap |= mask;
524
525 /*
526 * We could probably do a better job here. We are required to make
527 * bighint at least as large as the biggest contiguous block of
528 * data. If we just shoehorn it, a little extra overhead will
529 * be incured on the next allocation (but only that one typically).
530 */
531 scan->bm_bighint = BLIST_BMAP_RADIX;
532}
533
534/*
535 * BLST_META_FREE() - free allocated blocks from radix tree meta info
536 *
537 * This support routine frees a range of blocks from the bitmap.
538 * The range must be entirely enclosed by this radix node. If a
539 * meta node, we break the range down recursively to free blocks
540 * in subnodes (which means that this code can free an arbitrary
541 * range whereas the allocation code cannot allocate an arbitrary
542 * range).
543 */
544
545static void
35d5bbd3 546blst_meta_free(blmeta_t *scan, swblk_t freeBlk, swblk_t count,
79634a66 547 int64_t radix, int skip, swblk_t blk)
35d5bbd3 548{
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549 int i;
550 int next_skip = ((u_int)skip / BLIST_META_RADIX);
551
552#if 0
79634a66 553 kprintf("FREE (%x,%d) FROM (%x,%lld)\n",
984263bc 554 freeBlk, count,
79634a66 555 blk, (long long)radix
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556 );
557#endif
558
79634a66 559 /*
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560 * ALL-ALLOCATED special case, initialize for recursion.
561 *
562 * We will short-cut the ALL-ALLOCATED -> ALL-FREE case.
79634a66 563 */
984263bc 564 if (scan->u.bmu_avail == 0) {
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565 scan->u.bmu_avail = count;
566 scan->bm_bighint = count;
567
568 if (count != radix) {
569 for (i = 1; i <= skip; i += next_skip) {
35d5bbd3 570 if (scan[i].bm_bighint == (swblk_t)-1)
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571 break;
572 scan[i].bm_bighint = 0;
573 if (next_skip == 1) {
574 scan[i].u.bmu_bitmap = 0;
575 } else {
576 scan[i].u.bmu_avail = 0;
577 }
578 }
579 /* fall through */
580 }
581 } else {
582 scan->u.bmu_avail += count;
583 /* scan->bm_bighint = radix; */
584 }
585
586 /*
587 * ALL-FREE special case.
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588 *
589 * Set bighint for higher levels to snoop.
984263bc 590 */
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591 if (scan->u.bmu_avail == radix) {
592 scan->bm_bighint = radix;
984263bc 593 return;
3cd891f0 594 }
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595
596 /*
597 * Break the free down into its components
598 */
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599 if (scan->u.bmu_avail > radix) {
600 panic("blst_meta_free: freeing already "
601 "free blocks (%d) %d/%lld",
602 count, scan->u.bmu_avail, (long long)radix);
603 }
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604
605 radix /= BLIST_META_RADIX;
606
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607 i = (freeBlk - blk) / (swblk_t)radix;
608 blk += i * (swblk_t)radix;
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609 i = i * next_skip + 1;
610
611 while (i <= skip && blk < freeBlk + count) {
35d5bbd3 612 swblk_t v;
984263bc 613
79634a66 614 v = blk + (swblk_t)radix - freeBlk;
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615 if (v > count)
616 v = count;
617
35d5bbd3 618 if (scan->bm_bighint == (swblk_t)-1)
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619 panic("blst_meta_free: freeing unexpected range");
620
621 if (next_skip == 1) {
622 blst_leaf_free(&scan[i], freeBlk, v);
623 } else {
3cd891f0
MD
624 blst_meta_free(&scan[i], freeBlk, v,
625 radix, next_skip - 1, blk);
984263bc 626 }
3cd891f0
MD
627
628 /*
629 * After having dealt with the becomes-all-free case any
630 * partial free will not be able to bring us to the
631 * becomes-all-free state.
632 *
633 * We can raise bighint to at least the sub-segment's
634 * bighint.
635 */
636 if (scan->bm_bighint < scan[i].bm_bighint) {
984263bc 637 scan->bm_bighint = scan[i].bm_bighint;
3cd891f0 638 }
984263bc
MD
639 count -= v;
640 freeBlk += v;
79634a66 641 blk += (swblk_t)radix;
984263bc
MD
642 i += next_skip;
643 }
644}
645
9f3543c6
MD
646/*
647 * BLST_LEAF_FILL() - allocate specific blocks in leaf bitmap
648 *
649 * Allocates all blocks in the specified range regardless of
650 * any existing allocations in that range. Returns the number
651 * of blocks allocated by the call.
652 */
653static swblk_t
654blst_leaf_fill(blmeta_t *scan, swblk_t blk, int count)
655{
656 int n = blk & (BLIST_BMAP_RADIX - 1);
657 swblk_t nblks;
658 u_swblk_t mask, bitmap;
659
660 mask = ((u_swblk_t)-1 << n) &
661 ((u_swblk_t)-1 >> (BLIST_BMAP_RADIX - count - n));
662
663 /* Count the number of blocks we're about to allocate */
664 bitmap = scan->u.bmu_bitmap & mask;
665 for (nblks = 0; bitmap != 0; nblks++)
666 bitmap &= bitmap - 1;
667
668 scan->u.bmu_bitmap &= ~mask;
669 return (nblks);
670}
671
672/*
673 * BLST_META_FILL() - allocate specific blocks at a meta node
674 *
675 * Allocates the specified range of blocks, regardless of
676 * any existing allocations in the range. The range must
677 * be within the extent of this node. Returns the number
678 * of blocks allocated by the call.
679 */
680static swblk_t
681blst_meta_fill(blmeta_t *scan, swblk_t fillBlk, swblk_t count,
682 int64_t radix, int skip, swblk_t blk)
683{
684 int i;
685 int next_skip = ((u_int)skip / BLIST_META_RADIX);
686 swblk_t nblks = 0;
687
688 if (count == radix || scan->u.bmu_avail == 0) {
689 /*
690 * ALL-ALLOCATED special case
691 */
692 nblks = scan->u.bmu_avail;
693 scan->u.bmu_avail = 0;
694 scan->bm_bighint = count;
695 return (nblks);
696 }
697
698 if (scan->u.bmu_avail == radix) {
699 radix /= BLIST_META_RADIX;
700
701 /*
702 * ALL-FREE special case, initialize sublevel
703 */
704 for (i = 1; i <= skip; i += next_skip) {
705 if (scan[i].bm_bighint == (swblk_t)-1)
706 break;
707 if (next_skip == 1) {
708 scan[i].u.bmu_bitmap = (u_swblk_t)-1;
709 scan[i].bm_bighint = BLIST_BMAP_RADIX;
710 } else {
711 scan[i].bm_bighint = (swblk_t)radix;
712 scan[i].u.bmu_avail = (swblk_t)radix;
713 }
714 }
715 } else {
716 radix /= BLIST_META_RADIX;
717 }
718
719 if (count > (swblk_t)radix)
720 panic("blst_meta_fill: allocation too large");
721
722 i = (fillBlk - blk) / (swblk_t)radix;
723 blk += i * (swblk_t)radix;
724 i = i * next_skip + 1;
725
726 while (i <= skip && blk < fillBlk + count) {
727 swblk_t v;
728
729 v = blk + (swblk_t)radix - fillBlk;
730 if (v > count)
731 v = count;
732
733 if (scan->bm_bighint == (swblk_t)-1)
734 panic("blst_meta_fill: filling unexpected range");
735
736 if (next_skip == 1) {
737 nblks += blst_leaf_fill(&scan[i], fillBlk, v);
738 } else {
739 nblks += blst_meta_fill(&scan[i], fillBlk, v,
740 radix, next_skip - 1, blk);
741 }
742 count -= v;
743 fillBlk += v;
744 blk += (swblk_t)radix;
745 i += next_skip;
746 }
747 scan->u.bmu_avail -= nblks;
748 return (nblks);
749}
750
984263bc
MD
751/*
752 * BLIST_RADIX_COPY() - copy one radix tree to another
753 *
754 * Locates free space in the source tree and frees it in the destination
755 * tree. The space may not already be free in the destination.
756 */
757
35d5bbd3 758static void
79634a66 759blst_copy(blmeta_t *scan, swblk_t blk, int64_t radix,
35d5bbd3
MD
760 swblk_t skip, blist_t dest, swblk_t count)
761{
984263bc
MD
762 int next_skip;
763 int i;
764
765 /*
766 * Leaf node
767 */
768
769 if (radix == BLIST_BMAP_RADIX) {
35d5bbd3 770 u_swblk_t v = scan->u.bmu_bitmap;
984263bc 771
35d5bbd3 772 if (v == (u_swblk_t)-1) {
984263bc
MD
773 blist_free(dest, blk, count);
774 } else if (v != 0) {
775 int i;
776
777 for (i = 0; i < BLIST_BMAP_RADIX && i < count; ++i) {
778 if (v & (1 << i))
779 blist_free(dest, blk + i, 1);
780 }
781 }
782 return;
783 }
784
785 /*
786 * Meta node
787 */
788
789 if (scan->u.bmu_avail == 0) {
790 /*
791 * Source all allocated, leave dest allocated
792 */
793 return;
794 }
795 if (scan->u.bmu_avail == radix) {
796 /*
797 * Source all free, free entire dest
798 */
799 if (count < radix)
800 blist_free(dest, blk, count);
801 else
79634a66 802 blist_free(dest, blk, (swblk_t)radix);
984263bc
MD
803 return;
804 }
805
806
807 radix /= BLIST_META_RADIX;
808 next_skip = ((u_int)skip / BLIST_META_RADIX);
809
810 for (i = 1; count && i <= skip; i += next_skip) {
35d5bbd3 811 if (scan[i].bm_bighint == (swblk_t)-1)
984263bc
MD
812 break;
813
79634a66 814 if (count >= (swblk_t)radix) {
984263bc
MD
815 blst_copy(
816 &scan[i],
817 blk,
818 radix,
819 next_skip - 1,
820 dest,
79634a66 821 (swblk_t)radix
984263bc 822 );
79634a66 823 count -= (swblk_t)radix;
984263bc
MD
824 } else {
825 if (count) {
826 blst_copy(
827 &scan[i],
828 blk,
829 radix,
830 next_skip - 1,
831 dest,
832 count
833 );
834 }
835 count = 0;
836 }
79634a66 837 blk += (swblk_t)radix;
984263bc
MD
838 }
839}
840
841/*
842 * BLST_RADIX_INIT() - initialize radix tree
843 *
844 * Initialize our meta structures and bitmaps and calculate the exact
845 * amount of space required to manage 'count' blocks - this space may
846 * be considerably less then the calculated radix due to the large
847 * RADIX values we use.
848 */
849
35d5bbd3 850static swblk_t
79634a66 851blst_radix_init(blmeta_t *scan, int64_t radix, int skip, swblk_t count)
984263bc
MD
852{
853 int i;
854 int next_skip;
35d5bbd3 855 swblk_t memindex = 0;
984263bc
MD
856
857 /*
858 * Leaf node
859 */
860
861 if (radix == BLIST_BMAP_RADIX) {
862 if (scan) {
863 scan->bm_bighint = 0;
864 scan->u.bmu_bitmap = 0;
865 }
866 return(memindex);
867 }
868
869 /*
870 * Meta node. If allocating the entire object we can special
871 * case it. However, we need to figure out how much memory
872 * is required to manage 'count' blocks, so we continue on anyway.
873 */
874
875 if (scan) {
876 scan->bm_bighint = 0;
877 scan->u.bmu_avail = 0;
878 }
879
880 radix /= BLIST_META_RADIX;
881 next_skip = ((u_int)skip / BLIST_META_RADIX);
882
883 for (i = 1; i <= skip; i += next_skip) {
79634a66 884 if (count >= (swblk_t)radix) {
984263bc
MD
885 /*
886 * Allocate the entire object
887 */
888 memindex = i + blst_radix_init(
889 ((scan) ? &scan[i] : NULL),
890 radix,
891 next_skip - 1,
79634a66 892 (swblk_t)radix
984263bc 893 );
79634a66 894 count -= (swblk_t)radix;
984263bc
MD
895 } else if (count > 0) {
896 /*
897 * Allocate a partial object
898 */
899 memindex = i + blst_radix_init(
900 ((scan) ? &scan[i] : NULL),
901 radix,
902 next_skip - 1,
903 count
904 );
905 count = 0;
906 } else {
907 /*
908 * Add terminator and break out
909 */
910 if (scan)
35d5bbd3 911 scan[i].bm_bighint = (swblk_t)-1;
984263bc
MD
912 break;
913 }
914 }
915 if (memindex < i)
916 memindex = i;
917 return(memindex);
918}
919
920#ifdef BLIST_DEBUG
921
922static void
79634a66 923blst_radix_print(blmeta_t *scan, swblk_t blk, int64_t radix, int skip, int tab)
984263bc
MD
924{
925 int i;
926 int next_skip;
927 int lastState = 0;
928
929 if (radix == BLIST_BMAP_RADIX) {
6ea70f76 930 kprintf(
79634a66 931 "%*.*s(%04x,%lld): bitmap %08x big=%d\n",
984263bc 932 tab, tab, "",
79634a66 933 blk, (long long)radix,
984263bc
MD
934 scan->u.bmu_bitmap,
935 scan->bm_bighint
936 );
937 return;
938 }
939
940 if (scan->u.bmu_avail == 0) {
6ea70f76 941 kprintf(
79634a66 942 "%*.*s(%04x,%lld) ALL ALLOCATED\n",
984263bc
MD
943 tab, tab, "",
944 blk,
79634a66 945 (long long)radix
984263bc
MD
946 );
947 return;
948 }
949 if (scan->u.bmu_avail == radix) {
6ea70f76 950 kprintf(
79634a66 951 "%*.*s(%04x,%lld) ALL FREE\n",
984263bc
MD
952 tab, tab, "",
953 blk,
79634a66 954 (long long)radix
984263bc
MD
955 );
956 return;
957 }
958
6ea70f76 959 kprintf(
79634a66 960 "%*.*s(%04x,%lld): subtree (%d/%lld) big=%d {\n",
984263bc 961 tab, tab, "",
79634a66 962 blk, (long long)radix,
984263bc 963 scan->u.bmu_avail,
79634a66 964 (long long)radix,
984263bc
MD
965 scan->bm_bighint
966 );
967
968 radix /= BLIST_META_RADIX;
969 next_skip = ((u_int)skip / BLIST_META_RADIX);
970 tab += 4;
971
972 for (i = 1; i <= skip; i += next_skip) {
35d5bbd3 973 if (scan[i].bm_bighint == (swblk_t)-1) {
6ea70f76 974 kprintf(
79634a66 975 "%*.*s(%04x,%lld): Terminator\n",
984263bc 976 tab, tab, "",
79634a66 977 blk, (long long)radix
984263bc
MD
978 );
979 lastState = 0;
980 break;
981 }
982 blst_radix_print(
983 &scan[i],
984 blk,
985 radix,
986 next_skip - 1,
987 tab
988 );
79634a66 989 blk += (swblk_t)radix;
984263bc
MD
990 }
991 tab -= 4;
992
6ea70f76 993 kprintf(
984263bc
MD
994 "%*.*s}\n",
995 tab, tab, ""
996 );
997}
998
999#endif
1000
1001#ifdef BLIST_DEBUG
1002
1003int
1004main(int ac, char **av)
1005{
1006 int size = 1024;
1007 int i;
1008 blist_t bl;
1009
1010 for (i = 1; i < ac; ++i) {
1011 const char *ptr = av[i];
1012 if (*ptr != '-') {
1013 size = strtol(ptr, NULL, 0);
1014 continue;
1015 }
1016 ptr += 2;
1017 fprintf(stderr, "Bad option: %s\n", ptr - 2);
1018 exit(1);
1019 }
1020 bl = blist_create(size);
1021 blist_free(bl, 0, size);
1022
1023 for (;;) {
1024 char buf[1024];
35d5bbd3
MD
1025 swblk_t da = 0;
1026 swblk_t count = 0;
984263bc
MD
1027
1028
79634a66
MD
1029 kprintf("%d/%d/%lld> ",
1030 bl->bl_free, size, (long long)bl->bl_radix);
984263bc
MD
1031 fflush(stdout);
1032 if (fgets(buf, sizeof(buf), stdin) == NULL)
1033 break;
1034 switch(buf[0]) {
1035 case 'r':
1036 if (sscanf(buf + 1, "%d", &count) == 1) {
1037 blist_resize(&bl, count, 1);
651d8e75 1038 size = count;
984263bc 1039 } else {
6ea70f76 1040 kprintf("?\n");
984263bc
MD
1041 }
1042 case 'p':
1043 blist_print(bl);
1044 break;
1045 case 'a':
1046 if (sscanf(buf + 1, "%d", &count) == 1) {
35d5bbd3 1047 swblk_t blk = blist_alloc(bl, count);
6ea70f76 1048 kprintf(" R=%04x\n", blk);
984263bc 1049 } else {
6ea70f76 1050 kprintf("?\n");
984263bc
MD
1051 }
1052 break;
1053 case 'f':
1054 if (sscanf(buf + 1, "%x %d", &da, &count) == 2) {
1055 blist_free(bl, da, count);
1056 } else {
6ea70f76 1057 kprintf("?\n");
984263bc
MD
1058 }
1059 break;
9f3543c6
MD
1060 case 'l':
1061 if (sscanf(buf + 1, "%x %d", &da, &count) == 2) {
1062 printf(" n=%d\n",
1063 blist_fill(bl, da, count));
1064 } else {
1065 kprintf("?\n");
1066 }
1067 break;
984263bc
MD
1068 case '?':
1069 case 'h':
1070 puts(
1071 "p -print\n"
1072 "a %d -allocate\n"
1073 "f %x %d -free\n"
9f3543c6 1074 "l %x %d -fill\n"
984263bc
MD
1075 "r %d -resize\n"
1076 "h/? -help"
1077 );
1078 break;
1079 default:
6ea70f76 1080 kprintf("?\n");
984263bc
MD
1081 break;
1082 }
1083 }
1084 return(0);
1085}
1086
1087void
1088panic(const char *ctl, ...)
1089{
e2565a42 1090 __va_list va;
984263bc 1091
e2565a42 1092 __va_start(va, ctl);
984263bc
MD
1093 vfprintf(stderr, ctl, va);
1094 fprintf(stderr, "\n");
e2565a42 1095 __va_end(va);
984263bc
MD
1096 exit(1);
1097}
1098
1099#endif
1100