kern_malloc.c revision 1.20
1 /* $NetBSD: kern_malloc.c,v 1.20 1996/08/27 20:01:42 cgd Exp $ */ 2 3 /* 4 * Copyright 1996 Christopher G. Demetriou. All rights reserved. 5 * Copyright (c) 1987, 1991, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)kern_malloc.c 8.3 (Berkeley) 1/4/94 37 */ 38 39 #include <sys/param.h> 40 #include <sys/proc.h> 41 #include <sys/map.h> 42 #include <sys/kernel.h> 43 #include <sys/malloc.h> 44 #include <sys/systm.h> 45 46 #include <vm/vm.h> 47 #include <vm/vm_kern.h> 48 49 struct kmembuckets bucket[MINBUCKET + 16]; 50 struct kmemstats kmemstats[M_LAST]; 51 struct kmemusage *kmemusage; 52 char *kmembase, *kmemlimit; 53 char *memname[] = INITKMEMNAMES; 54 55 #ifdef DIAGNOSTIC 56 /* 57 * This structure provides a set of masks to catch unaligned frees. 58 */ 59 long addrmask[] = { 0, 60 0x00000001, 0x00000003, 0x00000007, 0x0000000f, 61 0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff, 62 0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff, 63 0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff, 64 }; 65 66 /* 67 * The WEIRD_ADDR is used as known text to copy into free objects so 68 * that modifications after frees can be detected. 69 */ 70 #define WEIRD_ADDR ((unsigned) 0xdeadbeef) 71 #define MAX_COPY 32 72 73 /* 74 * Normally the freelist structure is used only to hold the list pointer 75 * for free objects. However, when running with diagnostics, the first 76 * 8 bytes of the structure is unused except for diagnostic information, 77 * and the free list pointer is at offst 8 in the structure. Since the 78 * first 8 bytes is the portion of the structure most often modified, this 79 * helps to detect memory reuse problems and avoid free list corruption. 80 */ 81 struct freelist { 82 int32_t spare0; 83 int16_t type; 84 int16_t spare1; 85 caddr_t next; 86 }; 87 #else /* !DIAGNOSTIC */ 88 struct freelist { 89 caddr_t next; 90 }; 91 #endif /* DIAGNOSTIC */ 92 93 /* 94 * Allocate a block of memory 95 */ 96 void * 97 malloc(size, type, flags) 98 unsigned long size; 99 int type, flags; 100 { 101 register struct kmembuckets *kbp; 102 register struct kmemusage *kup; 103 register struct freelist *freep; 104 long indx, npg, allocsize; 105 int s; 106 caddr_t va, cp, savedlist; 107 #ifdef DIAGNOSTIC 108 int32_t *end, *lp; 109 int copysize; 110 char *savedtype; 111 #endif 112 #ifdef KMEMSTATS 113 register struct kmemstats *ksp = &kmemstats[type]; 114 115 if (((unsigned long)type) > M_LAST) 116 panic("malloc - bogus type"); 117 #endif 118 indx = BUCKETINDX(size); 119 kbp = &bucket[indx]; 120 s = splimp(); 121 #ifdef KMEMSTATS 122 while (ksp->ks_memuse >= ksp->ks_limit) { 123 if (flags & M_NOWAIT) { 124 splx(s); 125 return ((void *) NULL); 126 } 127 if (ksp->ks_limblocks < 65535) 128 ksp->ks_limblocks++; 129 tsleep((caddr_t)ksp, PSWP+2, memname[type], 0); 130 } 131 ksp->ks_size |= 1 << indx; 132 #endif 133 #ifdef DIAGNOSTIC 134 copysize = 1 << indx < MAX_COPY ? 1 << indx : MAX_COPY; 135 #endif 136 if (kbp->kb_next == NULL) { 137 kbp->kb_last = NULL; 138 if (size > MAXALLOCSAVE) 139 allocsize = roundup(size, CLBYTES); 140 else 141 allocsize = 1 << indx; 142 npg = clrnd(btoc(allocsize)); 143 va = (caddr_t) kmem_malloc(kmem_map, (vm_size_t)ctob(npg), 144 !(flags & M_NOWAIT)); 145 if (va == NULL) { 146 /* 147 * Kmem_malloc() can return NULL, even if it can 148 * wait, if there is no map space avaiable, because 149 * it can't fix that problem. Neither can we, 150 * right now. (We should release pages which 151 * are completely free and which are in buckets 152 * with too many free elements.) 153 */ 154 if ((flags & M_NOWAIT) == 0) 155 panic("malloc: out of space in kmem_map"); 156 splx(s); 157 return ((void *) NULL); 158 } 159 #ifdef KMEMSTATS 160 kbp->kb_total += kbp->kb_elmpercl; 161 #endif 162 kup = btokup(va); 163 kup->ku_indx = indx; 164 if (allocsize > MAXALLOCSAVE) { 165 if (npg > 65535) 166 panic("malloc: allocation too large"); 167 kup->ku_pagecnt = npg; 168 #ifdef KMEMSTATS 169 ksp->ks_memuse += allocsize; 170 #endif 171 goto out; 172 } 173 #ifdef KMEMSTATS 174 kup->ku_freecnt = kbp->kb_elmpercl; 175 kbp->kb_totalfree += kbp->kb_elmpercl; 176 #endif 177 /* 178 * Just in case we blocked while allocating memory, 179 * and someone else also allocated memory for this 180 * bucket, don't assume the list is still empty. 181 */ 182 savedlist = kbp->kb_next; 183 kbp->kb_next = cp = va + (npg * NBPG) - allocsize; 184 for (;;) { 185 freep = (struct freelist *)cp; 186 #ifdef DIAGNOSTIC 187 /* 188 * Copy in known text to detect modification 189 * after freeing. 190 */ 191 end = (int32_t *)&cp[copysize]; 192 for (lp = (int32_t *)cp; lp < end; lp++) 193 *lp = WEIRD_ADDR; 194 freep->type = M_FREE; 195 #endif /* DIAGNOSTIC */ 196 if (cp <= va) 197 break; 198 cp -= allocsize; 199 freep->next = cp; 200 } 201 freep->next = savedlist; 202 if (kbp->kb_last == NULL) 203 kbp->kb_last = (caddr_t)freep; 204 } 205 va = kbp->kb_next; 206 kbp->kb_next = ((struct freelist *)va)->next; 207 #ifdef DIAGNOSTIC 208 freep = (struct freelist *)va; 209 savedtype = (unsigned)freep->type < M_LAST ? 210 memname[freep->type] : "???"; 211 if (kbp->kb_next && 212 !kernacc(kbp->kb_next, sizeof(struct freelist), 0)) { 213 printf("%s %ld of object %p size %ld %s %s (invalid addr %p)\n", 214 "Data modified on freelist: word", 215 (long)((int32_t *)&kbp->kb_next - (int32_t *)kbp), 216 va, size, "previous type", savedtype, kbp->kb_next); 217 kbp->kb_next = NULL; 218 } 219 220 /* Fill the fields that we've used with WEIRD_ADDR */ 221 #if BYTE_ORDER == BIG_ENDIAN 222 freep->type = WEIRD_ADDR >> 16; 223 #endif 224 #if BYTE_ORDER == LITTLE_ENDIAN 225 freep->type = (short)WEIRD_ADDR; 226 #endif 227 end = (int32_t *)&freep->next + 228 (sizeof(freep->next) / sizeof(int32_t)); 229 for (lp = (int32_t *)&freep->next; lp < end; lp++) 230 *lp = WEIRD_ADDR; 231 232 /* and check that the data hasn't been modified. */ 233 end = (int32_t *)&va[copysize]; 234 for (lp = (int32_t *)va; lp < end; lp++) { 235 if (*lp == WEIRD_ADDR) 236 continue; 237 printf("%s %ld of object %p size %ld %s %s (0x%x != 0x%x)\n", 238 "Data modified on freelist: word", 239 (long)(lp - (int32_t *)va), va, size, "previous type", 240 savedtype, *lp, WEIRD_ADDR); 241 break; 242 } 243 244 freep->spare0 = 0; 245 #endif /* DIAGNOSTIC */ 246 #ifdef KMEMSTATS 247 kup = btokup(va); 248 if (kup->ku_indx != indx) 249 panic("malloc: wrong bucket"); 250 if (kup->ku_freecnt == 0) 251 panic("malloc: lost data"); 252 kup->ku_freecnt--; 253 kbp->kb_totalfree--; 254 ksp->ks_memuse += 1 << indx; 255 out: 256 kbp->kb_calls++; 257 ksp->ks_inuse++; 258 ksp->ks_calls++; 259 if (ksp->ks_memuse > ksp->ks_maxused) 260 ksp->ks_maxused = ksp->ks_memuse; 261 #else 262 out: 263 #endif 264 splx(s); 265 return ((void *) va); 266 } 267 268 /* 269 * Free a block of memory allocated by malloc. 270 */ 271 void 272 free(addr, type) 273 void *addr; 274 int type; 275 { 276 register struct kmembuckets *kbp; 277 register struct kmemusage *kup; 278 register struct freelist *freep; 279 long size; 280 int s; 281 #ifdef DIAGNOSTIC 282 caddr_t cp; 283 int32_t *end, *lp; 284 long alloc, copysize; 285 #endif 286 #ifdef KMEMSTATS 287 register struct kmemstats *ksp = &kmemstats[type]; 288 #endif 289 290 kup = btokup(addr); 291 size = 1 << kup->ku_indx; 292 kbp = &bucket[kup->ku_indx]; 293 s = splimp(); 294 #ifdef DIAGNOSTIC 295 /* 296 * Check for returns of data that do not point to the 297 * beginning of the allocation. 298 */ 299 if (size > NBPG * CLSIZE) 300 alloc = addrmask[BUCKETINDX(NBPG * CLSIZE)]; 301 else 302 alloc = addrmask[kup->ku_indx]; 303 if (((u_long)addr & alloc) != 0) 304 panic("free: unaligned addr %p, size %ld, type %s, mask %ld\n", 305 addr, size, memname[type], alloc); 306 #endif /* DIAGNOSTIC */ 307 if (size > MAXALLOCSAVE) { 308 kmem_free(kmem_map, (vm_offset_t)addr, ctob(kup->ku_pagecnt)); 309 #ifdef KMEMSTATS 310 size = kup->ku_pagecnt << PGSHIFT; 311 ksp->ks_memuse -= size; 312 kup->ku_indx = 0; 313 kup->ku_pagecnt = 0; 314 if (ksp->ks_memuse + size >= ksp->ks_limit && 315 ksp->ks_memuse < ksp->ks_limit) 316 wakeup((caddr_t)ksp); 317 ksp->ks_inuse--; 318 kbp->kb_total -= 1; 319 #endif 320 splx(s); 321 return; 322 } 323 freep = (struct freelist *)addr; 324 #ifdef DIAGNOSTIC 325 /* 326 * Check for multiple frees. Use a quick check to see if 327 * it looks free before laboriously searching the freelist. 328 */ 329 if (freep->spare0 == WEIRD_ADDR) { 330 for (cp = kbp->kb_next; cp; 331 cp = ((struct freelist *)cp)->next) { 332 if (addr != cp) 333 continue; 334 printf("multiply freed item %p\n", addr); 335 panic("free: duplicated free"); 336 } 337 } 338 /* 339 * Copy in known text to detect modification after freeing 340 * and to make it look free. Also, save the type being freed 341 * so we can list likely culprit if modification is detected 342 * when the object is reallocated. 343 */ 344 copysize = size < MAX_COPY ? size : MAX_COPY; 345 end = (int32_t *)&((caddr_t)addr)[copysize]; 346 for (lp = (int32_t *)addr; lp < end; lp++) 347 *lp = WEIRD_ADDR; 348 freep->type = type; 349 #endif /* DIAGNOSTIC */ 350 #ifdef KMEMSTATS 351 kup->ku_freecnt++; 352 if (kup->ku_freecnt >= kbp->kb_elmpercl) 353 if (kup->ku_freecnt > kbp->kb_elmpercl) 354 panic("free: multiple frees"); 355 else if (kbp->kb_totalfree > kbp->kb_highwat) 356 kbp->kb_couldfree++; 357 kbp->kb_totalfree++; 358 ksp->ks_memuse -= size; 359 if (ksp->ks_memuse + size >= ksp->ks_limit && 360 ksp->ks_memuse < ksp->ks_limit) 361 wakeup((caddr_t)ksp); 362 ksp->ks_inuse--; 363 #endif 364 if (kbp->kb_next == NULL) 365 kbp->kb_next = addr; 366 else 367 ((struct freelist *)kbp->kb_last)->next = addr; 368 freep->next = NULL; 369 kbp->kb_last = addr; 370 splx(s); 371 } 372 373 /* 374 * Change the size of a block of memory. 375 */ 376 void * 377 realloc(curaddr, newsize, type, flags) 378 void *curaddr; 379 unsigned long newsize; 380 int type, flags; 381 { 382 register struct kmemusage *kup; 383 long cursize; 384 void *newaddr; 385 #ifdef DIAGNOSTIC 386 long alloc; 387 #endif 388 389 /* 390 * Realloc() with a NULL pointer is the same as malloc(). 391 */ 392 if (curaddr == NULL) 393 return (malloc(newsize, type, flags)); 394 395 /* 396 * Realloc() with zero size is the same as free(). 397 */ 398 if (newsize == 0) { 399 free(curaddr, type); 400 return (NULL); 401 } 402 403 /* 404 * Find out how large the old allocation was (and do some 405 * sanity checking). 406 */ 407 kup = btokup(curaddr); 408 cursize = 1 << kup->ku_indx; 409 410 #ifdef DIAGNOSTIC 411 /* 412 * Check for returns of data that do not point to the 413 * beginning of the allocation. 414 */ 415 if (cursize > NBPG * CLSIZE) 416 alloc = addrmask[BUCKETINDX(NBPG * CLSIZE)]; 417 else 418 alloc = addrmask[kup->ku_indx]; 419 if (((u_long)curaddr & alloc) != 0) 420 panic("realloc: unaligned addr %p, size %ld, type %s, mask %ld\n", 421 curaddr, cursize, memname[type], alloc); 422 #endif /* DIAGNOSTIC */ 423 424 if (cursize > MAXALLOCSAVE) 425 cursize = ctob(kup->ku_pagecnt); 426 427 /* 428 * If we already actually have as much as they want, we're done. 429 */ 430 if (newsize <= cursize) 431 return (curaddr); 432 433 /* 434 * Can't satisfy the allocation with the existing block. 435 * Allocate a new one and copy the data. 436 */ 437 newaddr = malloc(newsize, type, flags); 438 if (newaddr == NULL) { 439 /* 440 * Malloc() failed, because flags included M_NOWAIT. 441 * Return NULL to indicate that failure. The old 442 * pointer is still valid. 443 */ 444 return NULL; 445 } 446 bcopy(curaddr, newaddr, cursize); 447 448 /* 449 * We were successful: free the old allocation and return 450 * the new one. 451 */ 452 free(curaddr, type); 453 return (newaddr); 454 } 455 456 /* 457 * Initialize the kernel memory allocator 458 */ 459 void 460 kmeminit() 461 { 462 register long indx; 463 int npg; 464 465 #if ((MAXALLOCSAVE & (MAXALLOCSAVE - 1)) != 0) 466 ERROR!_kmeminit:_MAXALLOCSAVE_not_power_of_2 467 #endif 468 #if (MAXALLOCSAVE > MINALLOCSIZE * 32768) 469 ERROR!_kmeminit:_MAXALLOCSAVE_too_big 470 #endif 471 #if (MAXALLOCSAVE < CLBYTES) 472 ERROR!_kmeminit:_MAXALLOCSAVE_too_small 473 #endif 474 475 if (sizeof(struct freelist) > (1 << MINBUCKET)) 476 panic("minbucket too small/struct freelist too big"); 477 478 npg = VM_KMEM_SIZE/ NBPG; 479 kmemusage = (struct kmemusage *) kmem_alloc(kernel_map, 480 (vm_size_t)(npg * sizeof(struct kmemusage))); 481 kmem_map = kmem_suballoc(kernel_map, (vm_offset_t *)&kmembase, 482 (vm_offset_t *)&kmemlimit, (vm_size_t)(npg * NBPG), FALSE); 483 #ifdef KMEMSTATS 484 for (indx = 0; indx < MINBUCKET + 16; indx++) { 485 if (1 << indx >= CLBYTES) 486 bucket[indx].kb_elmpercl = 1; 487 else 488 bucket[indx].kb_elmpercl = CLBYTES / (1 << indx); 489 bucket[indx].kb_highwat = 5 * bucket[indx].kb_elmpercl; 490 } 491 for (indx = 0; indx < M_LAST; indx++) 492 kmemstats[indx].ks_limit = npg * NBPG * 6 / 10; 493 #endif 494 } 495
Indexes created Thu Sep 25 02:09:54 GMT 2025