| 1 | /* $NetBSD: subr_blist.c,v 1.12 2013/12/09 09:35:17 wiz Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 1998 Matthew Dillon. All Rights Reserved. |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * 1. Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer in the |
| 12 | * documentation and/or other materials provided with the distribution. |
| 13 | * 4. Neither the name of the University nor the names of its contributors |
| 14 | * may be used to endorse or promote products derived from this software |
| 15 | * without specific prior written permission. |
| 16 | * |
| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS |
| 18 | * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| 19 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
| 21 | * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE |
| 23 | * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 24 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| 25 | * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| 26 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| 27 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 28 | */ |
| 29 | /* |
| 30 | * BLIST.C - Bitmap allocator/deallocator, using a radix tree with hinting |
| 31 | * |
| 32 | * This module implements a general bitmap allocator/deallocator. The |
| 33 | * allocator eats around 2 bits per 'block'. The module does not |
| 34 | * try to interpret the meaning of a 'block' other than to return |
| 35 | * BLIST_NONE on an allocation failure. |
| 36 | * |
| 37 | * A radix tree is used to maintain the bitmap. Two radix constants are |
| 38 | * involved: One for the bitmaps contained in the leaf nodes (typically |
| 39 | * 32), and one for the meta nodes (typically 16). Both meta and leaf |
| 40 | * nodes have a hint field. This field gives us a hint as to the largest |
| 41 | * free contiguous range of blocks under the node. It may contain a |
| 42 | * value that is too high, but will never contain a value that is too |
| 43 | * low. When the radix tree is searched, allocation failures in subtrees |
| 44 | * update the hint. |
| 45 | * |
| 46 | * The radix tree also implements two collapsed states for meta nodes: |
| 47 | * the ALL-ALLOCATED state and the ALL-FREE state. If a meta node is |
| 48 | * in either of these two states, all information contained underneath |
| 49 | * the node is considered stale. These states are used to optimize |
| 50 | * allocation and freeing operations. |
| 51 | * |
| 52 | * The hinting greatly increases code efficiency for allocations while |
| 53 | * the general radix structure optimizes both allocations and frees. The |
| 54 | * radix tree should be able to operate well no matter how much |
| 55 | * fragmentation there is and no matter how large a bitmap is used. |
| 56 | * |
| 57 | * Unlike the rlist code, the blist code wires all necessary memory at |
| 58 | * creation time. Neither allocations nor frees require interaction with |
| 59 | * the memory subsystem. In contrast, the rlist code may allocate memory |
| 60 | * on an rlist_free() call. The non-blocking features of the blist code |
| 61 | * are used to great advantage in the swap code (vm/nswap_pager.c). The |
| 62 | * rlist code uses a little less overall memory than the blist code (but |
| 63 | * due to swap interleaving not all that much less), but the blist code |
| 64 | * scales much, much better. |
| 65 | * |
| 66 | * LAYOUT: The radix tree is layed out recursively using a |
| 67 | * linear array. Each meta node is immediately followed (layed out |
| 68 | * sequentially in memory) by BLIST_META_RADIX lower level nodes. This |
| 69 | * is a recursive structure but one that can be easily scanned through |
| 70 | * a very simple 'skip' calculation. In order to support large radixes, |
| 71 | * portions of the tree may reside outside our memory allocation. We |
| 72 | * handle this with an early-termination optimization (when bighint is |
| 73 | * set to -1) on the scan. The memory allocation is only large enough |
| 74 | * to cover the number of blocks requested at creation time even if it |
| 75 | * must be encompassed in larger root-node radix. |
| 76 | * |
| 77 | * NOTE: the allocator cannot currently allocate more than |
| 78 | * BLIST_BMAP_RADIX blocks per call. It will panic with 'allocation too |
| 79 | * large' if you try. This is an area that could use improvement. The |
| 80 | * radix is large enough that this restriction does not effect the swap |
| 81 | * system, though. Currently only the allocation code is effected by |
| 82 | * this algorithmic unfeature. The freeing code can handle arbitrary |
| 83 | * ranges. |
| 84 | * |
| 85 | * This code can be compiled stand-alone for debugging. |
| 86 | */ |
| 87 | |
| 88 | #include <sys/cdefs.h> |
| 89 | __KERNEL_RCSID(0, "$NetBSD: subr_blist.c,v 1.12 2013/12/09 09:35:17 wiz Exp $" ); |
| 90 | #if 0 |
| 91 | __FBSDID("$FreeBSD: src/sys/kern/subr_blist.c,v 1.17 2004/06/04 04:03:25 alc Exp $" ); |
| 92 | #endif |
| 93 | |
| 94 | #ifdef _KERNEL |
| 95 | |
| 96 | #include <sys/param.h> |
| 97 | #include <sys/systm.h> |
| 98 | #include <sys/blist.h> |
| 99 | #include <sys/kmem.h> |
| 100 | |
| 101 | #else |
| 102 | |
| 103 | #ifndef BLIST_NO_DEBUG |
| 104 | #define BLIST_DEBUG |
| 105 | #endif |
| 106 | |
| 107 | #include <sys/types.h> |
| 108 | #include <stdio.h> |
| 109 | #include <string.h> |
| 110 | #include <stdlib.h> |
| 111 | #include <stdarg.h> |
| 112 | #include <inttypes.h> |
| 113 | |
| 114 | #define KM_SLEEP 1 |
| 115 | #define kmem_zalloc(a,b,c) calloc(1, (a)) |
| 116 | #define kmem_alloc(a,b,c) malloc(a) |
| 117 | #define kmem_free(a,b) free(a) |
| 118 | |
| 119 | #include "../sys/blist.h" |
| 120 | |
| 121 | void panic(const char *ctl, ...) __printflike(1, 2); |
| 122 | |
| 123 | #endif |
| 124 | |
| 125 | /* |
| 126 | * blmeta and bl_bitmap_t MUST be a power of 2 in size. |
| 127 | */ |
| 128 | |
| 129 | typedef struct blmeta { |
| 130 | union { |
| 131 | blist_blkno_t bmu_avail; /* space available under us */ |
| 132 | blist_bitmap_t bmu_bitmap; /* bitmap if we are a leaf */ |
| 133 | } u; |
| 134 | blist_blkno_t bm_bighint; /* biggest contiguous block hint*/ |
| 135 | } blmeta_t; |
| 136 | |
| 137 | struct blist { |
| 138 | blist_blkno_t bl_blocks; /* area of coverage */ |
| 139 | blist_blkno_t bl_radix; /* coverage radix */ |
| 140 | blist_blkno_t bl_skip; /* starting skip */ |
| 141 | blist_blkno_t bl_free; /* number of free blocks */ |
| 142 | blmeta_t *bl_root; /* root of radix tree */ |
| 143 | blist_blkno_t bl_rootblks; /* blks allocated for tree */ |
| 144 | }; |
| 145 | |
| 146 | #define BLIST_META_RADIX 16 |
| 147 | |
| 148 | /* |
| 149 | * static support functions |
| 150 | */ |
| 151 | |
| 152 | static blist_blkno_t blst_leaf_alloc(blmeta_t *scan, blist_blkno_t blk, |
| 153 | int count); |
| 154 | static blist_blkno_t blst_meta_alloc(blmeta_t *scan, blist_blkno_t blk, |
| 155 | blist_blkno_t count, blist_blkno_t radix, blist_blkno_t skip); |
| 156 | static void blst_leaf_free(blmeta_t *scan, blist_blkno_t relblk, int count); |
| 157 | static void blst_meta_free(blmeta_t *scan, blist_blkno_t freeBlk, |
| 158 | blist_blkno_t count, blist_blkno_t radix, blist_blkno_t skip, |
| 159 | blist_blkno_t blk); |
| 160 | static void blst_copy(blmeta_t *scan, blist_blkno_t blk, blist_blkno_t radix, |
| 161 | blist_blkno_t skip, blist_t dest, blist_blkno_t count); |
| 162 | static int blst_leaf_fill(blmeta_t *scan, blist_blkno_t blk, int count); |
| 163 | static blist_blkno_t blst_meta_fill(blmeta_t *scan, blist_blkno_t allocBlk, |
| 164 | blist_blkno_t count, blist_blkno_t radix, blist_blkno_t skip, |
| 165 | blist_blkno_t blk); |
| 166 | static blist_blkno_t blst_radix_init(blmeta_t *scan, blist_blkno_t radix, |
| 167 | blist_blkno_t skip, blist_blkno_t count); |
| 168 | #ifndef _KERNEL |
| 169 | static void blst_radix_print(blmeta_t *scan, blist_blkno_t blk, |
| 170 | blist_blkno_t radix, blist_blkno_t skip, int tab); |
| 171 | #endif |
| 172 | |
| 173 | /* |
| 174 | * blist_create() - create a blist capable of handling up to the specified |
| 175 | * number of blocks |
| 176 | * |
| 177 | * blocks must be greater than 0 |
| 178 | * |
| 179 | * The smallest blist consists of a single leaf node capable of |
| 180 | * managing BLIST_BMAP_RADIX blocks. |
| 181 | */ |
| 182 | |
| 183 | blist_t |
| 184 | blist_create(blist_blkno_t blocks) |
| 185 | { |
| 186 | blist_t bl; |
| 187 | blist_blkno_t radix; |
| 188 | blist_blkno_t skip = 0; |
| 189 | |
| 190 | /* |
| 191 | * Calculate radix and skip field used for scanning. |
| 192 | * |
| 193 | * XXX check overflow |
| 194 | */ |
| 195 | radix = BLIST_BMAP_RADIX; |
| 196 | |
| 197 | while (radix < blocks) { |
| 198 | radix *= BLIST_META_RADIX; |
| 199 | skip = (skip + 1) * BLIST_META_RADIX; |
| 200 | } |
| 201 | |
| 202 | bl = kmem_zalloc(sizeof(struct blist), KM_SLEEP); |
| 203 | |
| 204 | bl->bl_blocks = blocks; |
| 205 | bl->bl_radix = radix; |
| 206 | bl->bl_skip = skip; |
| 207 | bl->bl_rootblks = 1 + |
| 208 | blst_radix_init(NULL, bl->bl_radix, bl->bl_skip, blocks); |
| 209 | bl->bl_root = kmem_alloc(sizeof(blmeta_t) * bl->bl_rootblks, KM_SLEEP); |
| 210 | |
| 211 | #if defined(BLIST_DEBUG) |
| 212 | printf( |
| 213 | "BLIST representing %" PRIu64 " blocks (%" PRIu64 " MB of swap)" |
| 214 | ", requiring %" PRIu64 "K of ram\n" , |
| 215 | (uint64_t)bl->bl_blocks, |
| 216 | (uint64_t)bl->bl_blocks * 4 / 1024, |
| 217 | ((uint64_t)bl->bl_rootblks * sizeof(blmeta_t) + 1023) / 1024 |
| 218 | ); |
| 219 | printf("BLIST raw radix tree contains %" PRIu64 " records\n" , |
| 220 | (uint64_t)bl->bl_rootblks); |
| 221 | #endif |
| 222 | blst_radix_init(bl->bl_root, bl->bl_radix, bl->bl_skip, blocks); |
| 223 | |
| 224 | return(bl); |
| 225 | } |
| 226 | |
| 227 | void |
| 228 | blist_destroy(blist_t bl) |
| 229 | { |
| 230 | |
| 231 | kmem_free(bl->bl_root, sizeof(blmeta_t) * bl->bl_rootblks); |
| 232 | kmem_free(bl, sizeof(struct blist)); |
| 233 | } |
| 234 | |
| 235 | /* |
| 236 | * blist_alloc() - reserve space in the block bitmap. Return the base |
| 237 | * of a contiguous region or BLIST_NONE if space could |
| 238 | * not be allocated. |
| 239 | */ |
| 240 | |
| 241 | blist_blkno_t |
| 242 | blist_alloc(blist_t bl, blist_blkno_t count) |
| 243 | { |
| 244 | blist_blkno_t blk = BLIST_NONE; |
| 245 | |
| 246 | if (bl) { |
| 247 | if (bl->bl_radix == BLIST_BMAP_RADIX) |
| 248 | blk = blst_leaf_alloc(bl->bl_root, 0, count); |
| 249 | else |
| 250 | blk = blst_meta_alloc(bl->bl_root, 0, count, bl->bl_radix, bl->bl_skip); |
| 251 | if (blk != BLIST_NONE) |
| 252 | bl->bl_free -= count; |
| 253 | } |
| 254 | return(blk); |
| 255 | } |
| 256 | |
| 257 | /* |
| 258 | * blist_free() - free up space in the block bitmap. Return the base |
| 259 | * of a contiguous region. Panic if an inconsistancy is |
| 260 | * found. |
| 261 | */ |
| 262 | |
| 263 | void |
| 264 | blist_free(blist_t bl, blist_blkno_t blkno, blist_blkno_t count) |
| 265 | { |
| 266 | if (bl) { |
| 267 | if (bl->bl_radix == BLIST_BMAP_RADIX) |
| 268 | blst_leaf_free(bl->bl_root, blkno, count); |
| 269 | else |
| 270 | blst_meta_free(bl->bl_root, blkno, count, bl->bl_radix, bl->bl_skip, 0); |
| 271 | bl->bl_free += count; |
| 272 | } |
| 273 | } |
| 274 | |
| 275 | /* |
| 276 | * blist_fill() - mark a region in the block bitmap as off-limits |
| 277 | * to the allocator (i.e. allocate it), ignoring any |
| 278 | * existing allocations. Return the number of blocks |
| 279 | * actually filled that were free before the call. |
| 280 | */ |
| 281 | |
| 282 | blist_blkno_t |
| 283 | blist_fill(blist_t bl, blist_blkno_t blkno, blist_blkno_t count) |
| 284 | { |
| 285 | blist_blkno_t filled; |
| 286 | |
| 287 | if (bl) { |
| 288 | if (bl->bl_radix == BLIST_BMAP_RADIX) |
| 289 | filled = blst_leaf_fill(bl->bl_root, blkno, count); |
| 290 | else |
| 291 | filled = blst_meta_fill(bl->bl_root, blkno, count, |
| 292 | bl->bl_radix, bl->bl_skip, 0); |
| 293 | bl->bl_free -= filled; |
| 294 | return filled; |
| 295 | } else |
| 296 | return 0; |
| 297 | } |
| 298 | |
| 299 | /* |
| 300 | * blist_resize() - resize an existing radix tree to handle the |
| 301 | * specified number of blocks. This will reallocate |
| 302 | * the tree and transfer the previous bitmap to the new |
| 303 | * one. When extending the tree you can specify whether |
| 304 | * the new blocks are to left allocated or freed. |
| 305 | */ |
| 306 | |
| 307 | void |
| 308 | blist_resize(blist_t *pbl, blist_blkno_t count, int freenew) |
| 309 | { |
| 310 | blist_t newbl = blist_create(count); |
| 311 | blist_t save = *pbl; |
| 312 | |
| 313 | *pbl = newbl; |
| 314 | if (count > save->bl_blocks) |
| 315 | count = save->bl_blocks; |
| 316 | blst_copy(save->bl_root, 0, save->bl_radix, save->bl_skip, newbl, count); |
| 317 | |
| 318 | /* |
| 319 | * If resizing upwards, should we free the new space or not? |
| 320 | */ |
| 321 | if (freenew && count < newbl->bl_blocks) { |
| 322 | blist_free(newbl, count, newbl->bl_blocks - count); |
| 323 | } |
| 324 | blist_destroy(save); |
| 325 | } |
| 326 | |
| 327 | #ifdef BLIST_DEBUG |
| 328 | |
| 329 | /* |
| 330 | * blist_print() - dump radix tree |
| 331 | */ |
| 332 | |
| 333 | void |
| 334 | blist_print(blist_t bl) |
| 335 | { |
| 336 | printf("BLIST {\n" ); |
| 337 | blst_radix_print(bl->bl_root, 0, bl->bl_radix, bl->bl_skip, 4); |
| 338 | printf("}\n" ); |
| 339 | } |
| 340 | |
| 341 | #endif |
| 342 | |
| 343 | /************************************************************************ |
| 344 | * ALLOCATION SUPPORT FUNCTIONS * |
| 345 | ************************************************************************ |
| 346 | * |
| 347 | * These support functions do all the actual work. They may seem |
| 348 | * rather longish, but that's because I've commented them up. The |
| 349 | * actual code is straight forward. |
| 350 | * |
| 351 | */ |
| 352 | |
| 353 | /* |
| 354 | * blist_leaf_alloc() - allocate at a leaf in the radix tree (a bitmap). |
| 355 | * |
| 356 | * This is the core of the allocator and is optimized for the 1 block |
| 357 | * and the BLIST_BMAP_RADIX block allocation cases. Other cases are |
| 358 | * somewhat slower. The 1 block allocation case is log2 and extremely |
| 359 | * quick. |
| 360 | */ |
| 361 | |
| 362 | static blist_blkno_t |
| 363 | blst_leaf_alloc( |
| 364 | blmeta_t *scan, |
| 365 | blist_blkno_t blk, |
| 366 | int count |
| 367 | ) { |
| 368 | blist_bitmap_t orig = scan->u.bmu_bitmap; |
| 369 | |
| 370 | if (orig == 0) { |
| 371 | /* |
| 372 | * Optimize bitmap all-allocated case. Also, count = 1 |
| 373 | * case assumes at least 1 bit is free in the bitmap, so |
| 374 | * we have to take care of this case here. |
| 375 | */ |
| 376 | scan->bm_bighint = 0; |
| 377 | return(BLIST_NONE); |
| 378 | } |
| 379 | if (count == 1) { |
| 380 | /* |
| 381 | * Optimized code to allocate one bit out of the bitmap |
| 382 | */ |
| 383 | blist_bitmap_t mask; |
| 384 | int j = BLIST_BMAP_RADIX/2; |
| 385 | int r = 0; |
| 386 | |
| 387 | mask = (blist_bitmap_t)-1 >> (BLIST_BMAP_RADIX/2); |
| 388 | |
| 389 | while (j) { |
| 390 | if ((orig & mask) == 0) { |
| 391 | r += j; |
| 392 | orig >>= j; |
| 393 | } |
| 394 | j >>= 1; |
| 395 | mask >>= j; |
| 396 | } |
| 397 | scan->u.bmu_bitmap &= ~((blist_bitmap_t)1 << r); |
| 398 | return(blk + r); |
| 399 | } |
| 400 | if (count <= BLIST_BMAP_RADIX) { |
| 401 | /* |
| 402 | * non-optimized code to allocate N bits out of the bitmap. |
| 403 | * The more bits, the faster the code runs. It will run |
| 404 | * the slowest allocating 2 bits, but since there aren't any |
| 405 | * memory ops in the core loop (or shouldn't be, anyway), |
| 406 | * you probably won't notice the difference. |
| 407 | */ |
| 408 | int j; |
| 409 | int n = BLIST_BMAP_RADIX - count; |
| 410 | blist_bitmap_t mask; |
| 411 | |
| 412 | mask = (blist_bitmap_t)-1 >> n; |
| 413 | |
| 414 | for (j = 0; j <= n; ++j) { |
| 415 | if ((orig & mask) == mask) { |
| 416 | scan->u.bmu_bitmap &= ~mask; |
| 417 | return(blk + j); |
| 418 | } |
| 419 | mask = (mask << 1); |
| 420 | } |
| 421 | } |
| 422 | /* |
| 423 | * We couldn't allocate count in this subtree, update bighint. |
| 424 | */ |
| 425 | scan->bm_bighint = count - 1; |
| 426 | return(BLIST_NONE); |
| 427 | } |
| 428 | |
| 429 | /* |
| 430 | * blist_meta_alloc() - allocate at a meta in the radix tree. |
| 431 | * |
| 432 | * Attempt to allocate at a meta node. If we can't, we update |
| 433 | * bighint and return a failure. Updating bighint optimize future |
| 434 | * calls that hit this node. We have to check for our collapse cases |
| 435 | * and we have a few optimizations strewn in as well. |
| 436 | */ |
| 437 | |
| 438 | static blist_blkno_t |
| 439 | blst_meta_alloc( |
| 440 | blmeta_t *scan, |
| 441 | blist_blkno_t blk, |
| 442 | blist_blkno_t count, |
| 443 | blist_blkno_t radix, |
| 444 | blist_blkno_t skip |
| 445 | ) { |
| 446 | blist_blkno_t i; |
| 447 | blist_blkno_t next_skip = (skip / BLIST_META_RADIX); |
| 448 | |
| 449 | if (scan->u.bmu_avail == 0) { |
| 450 | /* |
| 451 | * ALL-ALLOCATED special case |
| 452 | */ |
| 453 | scan->bm_bighint = count; |
| 454 | return(BLIST_NONE); |
| 455 | } |
| 456 | |
| 457 | if (scan->u.bmu_avail == radix) { |
| 458 | radix /= BLIST_META_RADIX; |
| 459 | |
| 460 | /* |
| 461 | * ALL-FREE special case, initialize uninitialize |
| 462 | * sublevel. |
| 463 | */ |
| 464 | for (i = 1; i <= skip; i += next_skip) { |
| 465 | if (scan[i].bm_bighint == (blist_blkno_t)-1) |
| 466 | break; |
| 467 | if (next_skip == 1) { |
| 468 | scan[i].u.bmu_bitmap = (blist_bitmap_t)-1; |
| 469 | scan[i].bm_bighint = BLIST_BMAP_RADIX; |
| 470 | } else { |
| 471 | scan[i].bm_bighint = radix; |
| 472 | scan[i].u.bmu_avail = radix; |
| 473 | } |
| 474 | } |
| 475 | } else { |
| 476 | radix /= BLIST_META_RADIX; |
| 477 | } |
| 478 | |
| 479 | for (i = 1; i <= skip; i += next_skip) { |
| 480 | if (scan[i].bm_bighint == (blist_blkno_t)-1) { |
| 481 | /* |
| 482 | * Terminator |
| 483 | */ |
| 484 | break; |
| 485 | } else if (count <= scan[i].bm_bighint) { |
| 486 | /* |
| 487 | * count fits in object |
| 488 | */ |
| 489 | blist_blkno_t r; |
| 490 | if (next_skip == 1) { |
| 491 | r = blst_leaf_alloc(&scan[i], blk, count); |
| 492 | } else { |
| 493 | r = blst_meta_alloc(&scan[i], blk, count, radix, next_skip - 1); |
| 494 | } |
| 495 | if (r != BLIST_NONE) { |
| 496 | scan->u.bmu_avail -= count; |
| 497 | if (scan->bm_bighint > scan->u.bmu_avail) |
| 498 | scan->bm_bighint = scan->u.bmu_avail; |
| 499 | return(r); |
| 500 | } |
| 501 | } else if (count > radix) { |
| 502 | /* |
| 503 | * count does not fit in object even if it were |
| 504 | * complete free. |
| 505 | */ |
| 506 | panic("blist_meta_alloc: allocation too large" ); |
| 507 | } |
| 508 | blk += radix; |
| 509 | } |
| 510 | |
| 511 | /* |
| 512 | * We couldn't allocate count in this subtree, update bighint. |
| 513 | */ |
| 514 | if (scan->bm_bighint >= count) |
| 515 | scan->bm_bighint = count - 1; |
| 516 | return(BLIST_NONE); |
| 517 | } |
| 518 | |
| 519 | /* |
| 520 | * BLST_LEAF_FREE() - free allocated block from leaf bitmap |
| 521 | * |
| 522 | */ |
| 523 | |
| 524 | static void |
| 525 | blst_leaf_free( |
| 526 | blmeta_t *scan, |
| 527 | blist_blkno_t blk, |
| 528 | int count |
| 529 | ) { |
| 530 | /* |
| 531 | * free some data in this bitmap |
| 532 | * |
| 533 | * e.g. |
| 534 | * 0000111111111110000 |
| 535 | * \_________/\__/ |
| 536 | * v n |
| 537 | */ |
| 538 | int n = blk & (BLIST_BMAP_RADIX - 1); |
| 539 | blist_bitmap_t mask; |
| 540 | |
| 541 | mask = ((blist_bitmap_t)-1 << n) & |
| 542 | ((blist_bitmap_t)-1 >> (BLIST_BMAP_RADIX - count - n)); |
| 543 | |
| 544 | if (scan->u.bmu_bitmap & mask) |
| 545 | panic("blst_radix_free: freeing free block" ); |
| 546 | scan->u.bmu_bitmap |= mask; |
| 547 | |
| 548 | /* |
| 549 | * We could probably do a better job here. We are required to make |
| 550 | * bighint at least as large as the biggest contiguous block of |
| 551 | * data. If we just shoehorn it, a little extra overhead will |
| 552 | * be incured on the next allocation (but only that one typically). |
| 553 | */ |
| 554 | scan->bm_bighint = BLIST_BMAP_RADIX; |
| 555 | } |
| 556 | |
| 557 | /* |
| 558 | * BLST_META_FREE() - free allocated blocks from radix tree meta info |
| 559 | * |
| 560 | * This support routine frees a range of blocks from the bitmap. |
| 561 | * The range must be entirely enclosed by this radix node. If a |
| 562 | * meta node, we break the range down recursively to free blocks |
| 563 | * in subnodes (which means that this code can free an arbitrary |
| 564 | * range whereas the allocation code cannot allocate an arbitrary |
| 565 | * range). |
| 566 | */ |
| 567 | |
| 568 | static void |
| 569 | blst_meta_free( |
| 570 | blmeta_t *scan, |
| 571 | blist_blkno_t freeBlk, |
| 572 | blist_blkno_t count, |
| 573 | blist_blkno_t radix, |
| 574 | blist_blkno_t skip, |
| 575 | blist_blkno_t blk |
| 576 | ) { |
| 577 | blist_blkno_t i; |
| 578 | blist_blkno_t next_skip = (skip / BLIST_META_RADIX); |
| 579 | |
| 580 | #if 0 |
| 581 | printf("FREE (%" PRIx64 ",%" PRIu64 |
| 582 | ") FROM (%" PRIx64 ",%" PRIu64 ")\n" , |
| 583 | (uint64_t)freeBlk, (uint64_t)count, |
| 584 | (uint64_t)blk, (uint64_t)radix |
| 585 | ); |
| 586 | #endif |
| 587 | |
| 588 | if (scan->u.bmu_avail == 0) { |
| 589 | /* |
| 590 | * ALL-ALLOCATED special case, with possible |
| 591 | * shortcut to ALL-FREE special case. |
| 592 | */ |
| 593 | scan->u.bmu_avail = count; |
| 594 | scan->bm_bighint = count; |
| 595 | |
| 596 | if (count != radix) { |
| 597 | for (i = 1; i <= skip; i += next_skip) { |
| 598 | if (scan[i].bm_bighint == (blist_blkno_t)-1) |
| 599 | break; |
| 600 | scan[i].bm_bighint = 0; |
| 601 | if (next_skip == 1) { |
| 602 | scan[i].u.bmu_bitmap = 0; |
| 603 | } else { |
| 604 | scan[i].u.bmu_avail = 0; |
| 605 | } |
| 606 | } |
| 607 | /* fall through */ |
| 608 | } |
| 609 | } else { |
| 610 | scan->u.bmu_avail += count; |
| 611 | /* scan->bm_bighint = radix; */ |
| 612 | } |
| 613 | |
| 614 | /* |
| 615 | * ALL-FREE special case. |
| 616 | */ |
| 617 | |
| 618 | if (scan->u.bmu_avail == radix) |
| 619 | return; |
| 620 | if (scan->u.bmu_avail > radix) |
| 621 | panic("blst_meta_free: freeing already free blocks (%" |
| 622 | PRIu64 ") %" PRIu64 "/%" PRIu64, |
| 623 | (uint64_t)count, |
| 624 | (uint64_t)scan->u.bmu_avail, |
| 625 | (uint64_t)radix); |
| 626 | |
| 627 | /* |
| 628 | * Break the free down into its components |
| 629 | */ |
| 630 | |
| 631 | radix /= BLIST_META_RADIX; |
| 632 | |
| 633 | i = (freeBlk - blk) / radix; |
| 634 | blk += i * radix; |
| 635 | i = i * next_skip + 1; |
| 636 | |
| 637 | while (i <= skip && blk < freeBlk + count) { |
| 638 | blist_blkno_t v; |
| 639 | |
| 640 | v = blk + radix - freeBlk; |
| 641 | if (v > count) |
| 642 | v = count; |
| 643 | |
| 644 | if (scan->bm_bighint == (blist_blkno_t)-1) |
| 645 | panic("blst_meta_free: freeing unexpected range" ); |
| 646 | |
| 647 | if (next_skip == 1) { |
| 648 | blst_leaf_free(&scan[i], freeBlk, v); |
| 649 | } else { |
| 650 | blst_meta_free(&scan[i], freeBlk, v, radix, next_skip - 1, blk); |
| 651 | } |
| 652 | if (scan->bm_bighint < scan[i].bm_bighint) |
| 653 | scan->bm_bighint = scan[i].bm_bighint; |
| 654 | count -= v; |
| 655 | freeBlk += v; |
| 656 | blk += radix; |
| 657 | i += next_skip; |
| 658 | } |
| 659 | } |
| 660 | |
| 661 | /* |
| 662 | * BLIST_RADIX_COPY() - copy one radix tree to another |
| 663 | * |
| 664 | * Locates free space in the source tree and frees it in the destination |
| 665 | * tree. The space may not already be free in the destination. |
| 666 | */ |
| 667 | |
| 668 | static void blst_copy( |
| 669 | blmeta_t *scan, |
| 670 | blist_blkno_t blk, |
| 671 | blist_blkno_t radix, |
| 672 | blist_blkno_t skip, |
| 673 | blist_t dest, |
| 674 | blist_blkno_t count |
| 675 | ) { |
| 676 | blist_blkno_t next_skip; |
| 677 | blist_blkno_t i; |
| 678 | |
| 679 | /* |
| 680 | * Leaf node |
| 681 | */ |
| 682 | |
| 683 | if (radix == BLIST_BMAP_RADIX) { |
| 684 | blist_bitmap_t v = scan->u.bmu_bitmap; |
| 685 | |
| 686 | if (v == (blist_bitmap_t)-1) { |
| 687 | blist_free(dest, blk, count); |
| 688 | } else if (v != 0) { |
| 689 | int j; |
| 690 | |
| 691 | for (j = 0; j < BLIST_BMAP_RADIX && j < count; ++j) { |
| 692 | if (v & (1 << j)) |
| 693 | blist_free(dest, blk + j, 1); |
| 694 | } |
| 695 | } |
| 696 | return; |
| 697 | } |
| 698 | |
| 699 | /* |
| 700 | * Meta node |
| 701 | */ |
| 702 | |
| 703 | if (scan->u.bmu_avail == 0) { |
| 704 | /* |
| 705 | * Source all allocated, leave dest allocated |
| 706 | */ |
| 707 | return; |
| 708 | } |
| 709 | if (scan->u.bmu_avail == radix) { |
| 710 | /* |
| 711 | * Source all free, free entire dest |
| 712 | */ |
| 713 | if (count < radix) |
| 714 | blist_free(dest, blk, count); |
| 715 | else |
| 716 | blist_free(dest, blk, radix); |
| 717 | return; |
| 718 | } |
| 719 | |
| 720 | |
| 721 | radix /= BLIST_META_RADIX; |
| 722 | next_skip = (skip / BLIST_META_RADIX); |
| 723 | |
| 724 | for (i = 1; count && i <= skip; i += next_skip) { |
| 725 | if (scan[i].bm_bighint == (blist_blkno_t)-1) |
| 726 | break; |
| 727 | |
| 728 | if (count >= radix) { |
| 729 | blst_copy( |
| 730 | &scan[i], |
| 731 | blk, |
| 732 | radix, |
| 733 | next_skip - 1, |
| 734 | dest, |
| 735 | radix |
| 736 | ); |
| 737 | count -= radix; |
| 738 | } else { |
| 739 | if (count) { |
| 740 | blst_copy( |
| 741 | &scan[i], |
| 742 | blk, |
| 743 | radix, |
| 744 | next_skip - 1, |
| 745 | dest, |
| 746 | count |
| 747 | ); |
| 748 | } |
| 749 | count = 0; |
| 750 | } |
| 751 | blk += radix; |
| 752 | } |
| 753 | } |
| 754 | |
| 755 | /* |
| 756 | * BLST_LEAF_FILL() - allocate specific blocks in leaf bitmap |
| 757 | * |
| 758 | * This routine allocates all blocks in the specified range |
| 759 | * regardless of any existing allocations in that range. Returns |
| 760 | * the number of blocks allocated by the call. |
| 761 | */ |
| 762 | |
| 763 | static int |
| 764 | blst_leaf_fill(blmeta_t *scan, blist_blkno_t blk, int count) |
| 765 | { |
| 766 | int n = blk & (BLIST_BMAP_RADIX - 1); |
| 767 | int nblks; |
| 768 | blist_bitmap_t mask, bitmap; |
| 769 | |
| 770 | mask = ((blist_bitmap_t)-1 << n) & |
| 771 | ((blist_bitmap_t)-1 >> (BLIST_BMAP_RADIX - count - n)); |
| 772 | |
| 773 | /* Count the number of blocks we're about to allocate */ |
| 774 | bitmap = scan->u.bmu_bitmap & mask; |
| 775 | for (nblks = 0; bitmap != 0; nblks++) |
| 776 | bitmap &= bitmap - 1; |
| 777 | |
| 778 | scan->u.bmu_bitmap &= ~mask; |
| 779 | return nblks; |
| 780 | } |
| 781 | |
| 782 | /* |
| 783 | * BLIST_META_FILL() - allocate specific blocks at a meta node |
| 784 | * |
| 785 | * This routine allocates the specified range of blocks, |
| 786 | * regardless of any existing allocations in the range. The |
| 787 | * range must be within the extent of this node. Returns the |
| 788 | * number of blocks allocated by the call. |
| 789 | */ |
| 790 | static blist_blkno_t |
| 791 | blst_meta_fill( |
| 792 | blmeta_t *scan, |
| 793 | blist_blkno_t allocBlk, |
| 794 | blist_blkno_t count, |
| 795 | blist_blkno_t radix, |
| 796 | blist_blkno_t skip, |
| 797 | blist_blkno_t blk |
| 798 | ) { |
| 799 | blist_blkno_t i; |
| 800 | blist_blkno_t next_skip = (skip / BLIST_META_RADIX); |
| 801 | blist_blkno_t nblks = 0; |
| 802 | |
| 803 | if (count == radix || scan->u.bmu_avail == 0) { |
| 804 | /* |
| 805 | * ALL-ALLOCATED special case |
| 806 | */ |
| 807 | nblks = scan->u.bmu_avail; |
| 808 | scan->u.bmu_avail = 0; |
| 809 | scan->bm_bighint = count; |
| 810 | return nblks; |
| 811 | } |
| 812 | |
| 813 | if (count > radix) |
| 814 | panic("blist_meta_fill: allocation too large" ); |
| 815 | |
| 816 | if (scan->u.bmu_avail == radix) { |
| 817 | radix /= BLIST_META_RADIX; |
| 818 | |
| 819 | /* |
| 820 | * ALL-FREE special case, initialize sublevel |
| 821 | */ |
| 822 | for (i = 1; i <= skip; i += next_skip) { |
| 823 | if (scan[i].bm_bighint == (blist_blkno_t)-1) |
| 824 | break; |
| 825 | if (next_skip == 1) { |
| 826 | scan[i].u.bmu_bitmap = (blist_bitmap_t)-1; |
| 827 | scan[i].bm_bighint = BLIST_BMAP_RADIX; |
| 828 | } else { |
| 829 | scan[i].bm_bighint = radix; |
| 830 | scan[i].u.bmu_avail = radix; |
| 831 | } |
| 832 | } |
| 833 | } else { |
| 834 | radix /= BLIST_META_RADIX; |
| 835 | } |
| 836 | |
| 837 | i = (allocBlk - blk) / radix; |
| 838 | blk += i * radix; |
| 839 | i = i * next_skip + 1; |
| 840 | |
| 841 | while (i <= skip && blk < allocBlk + count) { |
| 842 | blist_blkno_t v; |
| 843 | |
| 844 | v = blk + radix - allocBlk; |
| 845 | if (v > count) |
| 846 | v = count; |
| 847 | |
| 848 | if (scan->bm_bighint == (blist_blkno_t)-1) |
| 849 | panic("blst_meta_fill: filling unexpected range" ); |
| 850 | |
| 851 | if (next_skip == 1) { |
| 852 | nblks += blst_leaf_fill(&scan[i], allocBlk, v); |
| 853 | } else { |
| 854 | nblks += blst_meta_fill(&scan[i], allocBlk, v, |
| 855 | radix, next_skip - 1, blk); |
| 856 | } |
| 857 | count -= v; |
| 858 | allocBlk += v; |
| 859 | blk += radix; |
| 860 | i += next_skip; |
| 861 | } |
| 862 | scan->u.bmu_avail -= nblks; |
| 863 | return nblks; |
| 864 | } |
| 865 | |
| 866 | /* |
| 867 | * BLST_RADIX_INIT() - initialize radix tree |
| 868 | * |
| 869 | * Initialize our meta structures and bitmaps and calculate the exact |
| 870 | * amount of space required to manage 'count' blocks - this space may |
| 871 | * be considerably less than the calculated radix due to the large |
| 872 | * RADIX values we use. |
| 873 | */ |
| 874 | |
| 875 | static blist_blkno_t |
| 876 | blst_radix_init(blmeta_t *scan, blist_blkno_t radix, blist_blkno_t skip, |
| 877 | blist_blkno_t count) |
| 878 | { |
| 879 | blist_blkno_t i; |
| 880 | blist_blkno_t next_skip; |
| 881 | blist_blkno_t memindex = 0; |
| 882 | |
| 883 | /* |
| 884 | * Leaf node |
| 885 | */ |
| 886 | |
| 887 | if (radix == BLIST_BMAP_RADIX) { |
| 888 | if (scan) { |
| 889 | scan->bm_bighint = 0; |
| 890 | scan->u.bmu_bitmap = 0; |
| 891 | } |
| 892 | return(memindex); |
| 893 | } |
| 894 | |
| 895 | /* |
| 896 | * Meta node. If allocating the entire object we can special |
| 897 | * case it. However, we need to figure out how much memory |
| 898 | * is required to manage 'count' blocks, so we continue on anyway. |
| 899 | */ |
| 900 | |
| 901 | if (scan) { |
| 902 | scan->bm_bighint = 0; |
| 903 | scan->u.bmu_avail = 0; |
| 904 | } |
| 905 | |
| 906 | radix /= BLIST_META_RADIX; |
| 907 | next_skip = (skip / BLIST_META_RADIX); |
| 908 | |
| 909 | for (i = 1; i <= skip; i += next_skip) { |
| 910 | if (count >= radix) { |
| 911 | /* |
| 912 | * Allocate the entire object |
| 913 | */ |
| 914 | memindex = i + blst_radix_init( |
| 915 | ((scan) ? &scan[i] : NULL), |
| 916 | radix, |
| 917 | next_skip - 1, |
| 918 | radix |
| 919 | ); |
| 920 | count -= radix; |
| 921 | } else if (count > 0) { |
| 922 | /* |
| 923 | * Allocate a partial object |
| 924 | */ |
| 925 | memindex = i + blst_radix_init( |
| 926 | ((scan) ? &scan[i] : NULL), |
| 927 | radix, |
| 928 | next_skip - 1, |
| 929 | count |
| 930 | ); |
| 931 | count = 0; |
| 932 | } else { |
| 933 | /* |
| 934 | * Add terminator and break out |
| 935 | */ |
| 936 | if (scan) |
| 937 | scan[i].bm_bighint = (blist_blkno_t)-1; |
| 938 | break; |
| 939 | } |
| 940 | } |
| 941 | if (memindex < i) |
| 942 | memindex = i; |
| 943 | return(memindex); |
| 944 | } |
| 945 | |
| 946 | #ifdef BLIST_DEBUG |
| 947 | |
| 948 | static void |
| 949 | blst_radix_print(blmeta_t *scan, blist_blkno_t blk, blist_blkno_t radix, |
| 950 | blist_blkno_t skip, int tab) |
| 951 | { |
| 952 | blist_blkno_t i; |
| 953 | blist_blkno_t next_skip; |
| 954 | int lastState = 0; |
| 955 | |
| 956 | if (radix == BLIST_BMAP_RADIX) { |
| 957 | printf( |
| 958 | "%*.*s(%0*" PRIx64 ",%" PRIu64 |
| 959 | "): bitmap %0*" PRIx64 " big=%" PRIu64 "\n" , |
| 960 | tab, tab, "" , |
| 961 | sizeof(blk) * 2, |
| 962 | (uint64_t)blk, |
| 963 | (uint64_t)radix, |
| 964 | sizeof(scan->u.bmu_bitmap) * 2, |
| 965 | (uint64_t)scan->u.bmu_bitmap, |
| 966 | (uint64_t)scan->bm_bighint |
| 967 | ); |
| 968 | return; |
| 969 | } |
| 970 | |
| 971 | if (scan->u.bmu_avail == 0) { |
| 972 | printf( |
| 973 | "%*.*s(%0*" PRIx64 ",%" PRIu64") ALL ALLOCATED\n" , |
| 974 | tab, tab, "" , |
| 975 | sizeof(blk) * 2, |
| 976 | (uint64_t)blk, |
| 977 | (uint64_t)radix |
| 978 | ); |
| 979 | return; |
| 980 | } |
| 981 | if (scan->u.bmu_avail == radix) { |
| 982 | printf( |
| 983 | "%*.*s(%0*" PRIx64 ",%" PRIu64 ") ALL FREE\n" , |
| 984 | tab, tab, "" , |
| 985 | sizeof(blk) * 2, |
| 986 | (uint64_t)blk, |
| 987 | (uint64_t)radix |
| 988 | ); |
| 989 | return; |
| 990 | } |
| 991 | |
| 992 | printf( |
| 993 | "%*.*s(%0*" PRIx64 ",%" PRIu64 "): subtree (%" PRIu64 "/%" |
| 994 | PRIu64 ") big=%" PRIu64 " {\n" , |
| 995 | tab, tab, "" , |
| 996 | sizeof(blk) * 2, |
| 997 | (uint64_t)blk, |
| 998 | (uint64_t)radix, |
| 999 | (uint64_t)scan->u.bmu_avail, |
| 1000 | (uint64_t)radix, |
| 1001 | (uint64_t)scan->bm_bighint |
| 1002 | ); |
| 1003 | |
| 1004 | radix /= BLIST_META_RADIX; |
| 1005 | next_skip = (skip / BLIST_META_RADIX); |
| 1006 | tab += 4; |
| 1007 | |
| 1008 | for (i = 1; i <= skip; i += next_skip) { |
| 1009 | if (scan[i].bm_bighint == (blist_blkno_t)-1) { |
| 1010 | printf( |
| 1011 | "%*.*s(%0*" PRIx64 ",%" PRIu64 "): Terminator\n" , |
| 1012 | tab, tab, "" , |
| 1013 | sizeof(blk) * 2, |
| 1014 | (uint64_t)blk, |
| 1015 | (uint64_t)radix |
| 1016 | ); |
| 1017 | lastState = 0; |
| 1018 | break; |
| 1019 | } |
| 1020 | blst_radix_print( |
| 1021 | &scan[i], |
| 1022 | blk, |
| 1023 | radix, |
| 1024 | next_skip - 1, |
| 1025 | tab |
| 1026 | ); |
| 1027 | blk += radix; |
| 1028 | } |
| 1029 | tab -= 4; |
| 1030 | |
| 1031 | printf( |
| 1032 | "%*.*s}\n" , |
| 1033 | tab, tab, "" |
| 1034 | ); |
| 1035 | } |
| 1036 | |
| 1037 | #endif |
| 1038 | |
| 1039 | #ifdef BLIST_DEBUG |
| 1040 | |
| 1041 | int |
| 1042 | main(int ac, char **av) |
| 1043 | { |
| 1044 | blist_blkno_t size = 1024; |
| 1045 | int i; |
| 1046 | blist_t bl; |
| 1047 | |
| 1048 | for (i = 1; i < ac; ++i) { |
| 1049 | const char *ptr = av[i]; |
| 1050 | if (*ptr != '-') { |
| 1051 | size = strtol(ptr, NULL, 0); |
| 1052 | continue; |
| 1053 | } |
| 1054 | ptr += 2; |
| 1055 | fprintf(stderr, "Bad option: %s\n" , ptr - 2); |
| 1056 | exit(1); |
| 1057 | } |
| 1058 | bl = blist_create(size); |
| 1059 | blist_free(bl, 0, size); |
| 1060 | |
| 1061 | for (;;) { |
| 1062 | char buf[1024]; |
| 1063 | uint64_t da = 0; |
| 1064 | uint64_t count = 0; |
| 1065 | |
| 1066 | printf("%" PRIu64 "/%" PRIu64 "/%" PRIu64 "> " , |
| 1067 | (uint64_t)bl->bl_free, |
| 1068 | (uint64_t)size, |
| 1069 | (uint64_t)bl->bl_radix); |
| 1070 | fflush(stdout); |
| 1071 | if (fgets(buf, sizeof(buf), stdin) == NULL) |
| 1072 | break; |
| 1073 | switch(buf[0]) { |
| 1074 | case 'r': |
| 1075 | if (sscanf(buf + 1, "%" SCNu64, &count) == 1) { |
| 1076 | blist_resize(&bl, count, 1); |
| 1077 | } else { |
| 1078 | printf("?\n" ); |
| 1079 | } |
| 1080 | case 'p': |
| 1081 | blist_print(bl); |
| 1082 | break; |
| 1083 | case 'a': |
| 1084 | if (sscanf(buf + 1, "%" SCNu64, &count) == 1) { |
| 1085 | blist_blkno_t blk = blist_alloc(bl, count); |
| 1086 | printf(" R=%0*" PRIx64 "\n" , |
| 1087 | sizeof(blk) * 2, |
| 1088 | (uint64_t)blk); |
| 1089 | } else { |
| 1090 | printf("?\n" ); |
| 1091 | } |
| 1092 | break; |
| 1093 | case 'f': |
| 1094 | if (sscanf(buf + 1, "%" SCNx64 " %" SCNu64, |
| 1095 | &da, &count) == 2) { |
| 1096 | blist_free(bl, da, count); |
| 1097 | } else { |
| 1098 | printf("?\n" ); |
| 1099 | } |
| 1100 | break; |
| 1101 | case 'l': |
| 1102 | if (sscanf(buf + 1, "%" SCNx64 " %" SCNu64, |
| 1103 | &da, &count) == 2) { |
| 1104 | printf(" n=%" PRIu64 "\n" , |
| 1105 | (uint64_t)blist_fill(bl, da, count)); |
| 1106 | } else { |
| 1107 | printf("?\n" ); |
| 1108 | } |
| 1109 | break; |
| 1110 | case '?': |
| 1111 | case 'h': |
| 1112 | puts( |
| 1113 | "p -print\n" |
| 1114 | "a %d -allocate\n" |
| 1115 | "f %x %d -free\n" |
| 1116 | "l %x %d -fill\n" |
| 1117 | "r %d -resize\n" |
| 1118 | "h/? -help" |
| 1119 | ); |
| 1120 | break; |
| 1121 | default: |
| 1122 | printf("?\n" ); |
| 1123 | break; |
| 1124 | } |
| 1125 | } |
| 1126 | return(0); |
| 1127 | } |
| 1128 | |
| 1129 | void |
| 1130 | panic(const char *ctl, ...) |
| 1131 | { |
| 1132 | va_list va; |
| 1133 | |
| 1134 | va_start(va, ctl); |
| 1135 | vfprintf(stderr, ctl, va); |
| 1136 | fprintf(stderr, "\n" ); |
| 1137 | va_end(va); |
| 1138 | exit(1); |
| 1139 | } |
| 1140 | |
| 1141 | #endif |
| 1142 | |
| 1143 | |