Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_malloc.c
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1 /* 2 * Copyright (c) 1987, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 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 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)kern_malloc.c 8.3 (Berkeley) 1/4/94 34 * $FreeBSD$ 35 */ 36 37 #include "opt_vm.h" 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/kernel.h> 42 #define MALLOC_INSTANTIATE 43 #include <sys/malloc.h> 44 #include <sys/mbuf.h> 45 #include <sys/vmmeter.h> 46 #include <sys/lock.h> 47 48 #include <vm/vm.h> 49 #include <vm/vm_param.h> 50 #include <vm/vm_kern.h> 51 #include <vm/vm_extern.h> 52 #include <vm/pmap.h> 53 #include <vm/vm_map.h> 54 55 static void kmeminit __P((void *)); 56 SYSINIT(kmem, SI_SUB_KMEM, SI_ORDER_FIRST, kmeminit, NULL) 57 58 static MALLOC_DEFINE(M_FREE, "free", "should be on free list"); 59 60 static struct malloc_type *kmemstatistics; 61 static struct kmembuckets bucket[MINBUCKET + 16]; 62 static struct kmemusage *kmemusage; 63 static char *kmembase; 64 static char *kmemlimit; 65 static int vm_kmem_size; 66 67 #ifdef INVARIANTS 68 /* 69 * This structure provides a set of masks to catch unaligned frees. 70 */ 71 static long addrmask[] = { 0, 72 0x00000001, 0x00000003, 0x00000007, 0x0000000f, 73 0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff, 74 0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff, 75 0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff, 76 }; 77 78 /* 79 * The WEIRD_ADDR is used as known text to copy into free objects so 80 * that modifications after frees can be detected. 81 */ 82 #define WEIRD_ADDR 0xdeadc0de 83 #define MAX_COPY 64 84 85 /* 86 * Normally the first word of the structure is used to hold the list 87 * pointer for free objects. However, when running with diagnostics, 88 * we use the third and fourth fields, so as to catch modifications 89 * in the most commonly trashed first two words. 90 */ 91 struct freelist { 92 long spare0; 93 struct malloc_type *type; 94 long spare1; 95 caddr_t next; 96 }; 97 #else /* !INVARIANTS */ 98 struct freelist { 99 caddr_t next; 100 }; 101 #endif /* INVARIANTS */ 102 103 /* 104 * Allocate a block of memory 105 */ 106 void * 107 malloc(size, type, flags) 108 unsigned long size; 109 struct malloc_type *type; 110 int flags; 111 { 112 register struct kmembuckets *kbp; 113 register struct kmemusage *kup; 114 register struct freelist *freep; 115 long indx, npg, allocsize; 116 int s; 117 caddr_t va, cp, savedlist; 118 #ifdef INVARIANTS 119 long *end, *lp; 120 int copysize; 121 char *savedtype; 122 #endif 123 register struct malloc_type *ksp = type; 124 125 /* 126 * Must be at splmem() prior to initializing segment to handle 127 * potential initialization race. 128 */ 129 130 s = splmem(); 131 132 if (type->ks_limit == 0) 133 malloc_init(type); 134 135 indx = BUCKETINDX(size); 136 kbp = &bucket[indx]; 137 while (ksp->ks_memuse >= ksp->ks_limit) { 138 if (flags & M_NOWAIT) { 139 splx(s); 140 return ((void *) NULL); 141 } 142 if (ksp->ks_limblocks < 65535) 143 ksp->ks_limblocks++; 144 tsleep((caddr_t)ksp, PSWP+2, type->ks_shortdesc, 0); 145 } 146 ksp->ks_size |= 1 << indx; 147 #ifdef INVARIANTS 148 copysize = 1 << indx < MAX_COPY ? 1 << indx : MAX_COPY; 149 #endif 150 if (kbp->kb_next == NULL) { 151 kbp->kb_last = NULL; 152 if (size > MAXALLOCSAVE) 153 allocsize = roundup(size, PAGE_SIZE); 154 else 155 allocsize = 1 << indx; 156 npg = btoc(allocsize); 157 va = (caddr_t) kmem_malloc(kmem_map, (vm_size_t)ctob(npg), flags); 158 if (va == NULL) { 159 splx(s); 160 return ((void *) NULL); 161 } 162 kbp->kb_total += kbp->kb_elmpercl; 163 kup = btokup(va); 164 kup->ku_indx = indx; 165 if (allocsize > MAXALLOCSAVE) { 166 if (npg > 65535) 167 panic("malloc: allocation too large"); 168 kup->ku_pagecnt = npg; 169 ksp->ks_memuse += allocsize; 170 goto out; 171 } 172 kup->ku_freecnt = kbp->kb_elmpercl; 173 kbp->kb_totalfree += kbp->kb_elmpercl; 174 /* 175 * Just in case we blocked while allocating memory, 176 * and someone else also allocated memory for this 177 * bucket, don't assume the list is still empty. 178 */ 179 savedlist = kbp->kb_next; 180 kbp->kb_next = cp = va + (npg * PAGE_SIZE) - allocsize; 181 for (;;) { 182 freep = (struct freelist *)cp; 183 #ifdef INVARIANTS 184 /* 185 * Copy in known text to detect modification 186 * after freeing. 187 */ 188 end = (long *)&cp[copysize]; 189 for (lp = (long *)cp; lp < end; lp++) 190 *lp = WEIRD_ADDR; 191 freep->type = M_FREE; 192 #endif /* INVARIANTS */ 193 if (cp <= va) 194 break; 195 cp -= allocsize; 196 freep->next = cp; 197 } 198 freep->next = savedlist; 199 if (kbp->kb_last == NULL) 200 kbp->kb_last = (caddr_t)freep; 201 } 202 va = kbp->kb_next; 203 kbp->kb_next = ((struct freelist *)va)->next; 204 #ifdef INVARIANTS 205 freep = (struct freelist *)va; 206 savedtype = (char *) type->ks_shortdesc; 207 #if BYTE_ORDER == BIG_ENDIAN 208 freep->type = (struct malloc_type *)WEIRD_ADDR >> 16; 209 #endif 210 #if BYTE_ORDER == LITTLE_ENDIAN 211 freep->type = (struct malloc_type *)WEIRD_ADDR; 212 #endif 213 if ((intptr_t)(void *)&freep->next & 0x2) 214 freep->next = (caddr_t)((WEIRD_ADDR >> 16)|(WEIRD_ADDR << 16)); 215 else 216 freep->next = (caddr_t)WEIRD_ADDR; 217 end = (long *)&va[copysize]; 218 for (lp = (long *)va; lp < end; lp++) { 219 if (*lp == WEIRD_ADDR) 220 continue; 221 printf("%s %ld of object %p size %lu %s %s (0x%lx != 0x%lx)\n", 222 "Data modified on freelist: word", 223 (long)(lp - (long *)va), (void *)va, size, 224 "previous type", savedtype, *lp, (u_long)WEIRD_ADDR); 225 break; 226 } 227 freep->spare0 = 0; 228 #endif /* INVARIANTS */ 229 kup = btokup(va); 230 if (kup->ku_indx != indx) 231 panic("malloc: wrong bucket"); 232 if (kup->ku_freecnt == 0) 233 panic("malloc: lost data"); 234 kup->ku_freecnt--; 235 kbp->kb_totalfree--; 236 ksp->ks_memuse += 1 << indx; 237 out: 238 kbp->kb_calls++; 239 ksp->ks_inuse++; 240 ksp->ks_calls++; 241 if (ksp->ks_memuse > ksp->ks_maxused) 242 ksp->ks_maxused = ksp->ks_memuse; 243 splx(s); 244 return ((void *) va); 245 } 246 247 /* 248 * Free a block of memory allocated by malloc. 249 */ 250 void 251 free(addr, type) 252 void *addr; 253 struct malloc_type *type; 254 { 255 register struct kmembuckets *kbp; 256 register struct kmemusage *kup; 257 register struct freelist *freep; 258 long size; 259 int s; 260 #ifdef INVARIANTS 261 struct freelist *fp; 262 long *end, *lp, alloc, copysize; 263 #endif 264 register struct malloc_type *ksp = type; 265 266 if (type->ks_limit == 0) 267 panic("freeing with unknown type (%s)", type->ks_shortdesc); 268 269 KASSERT(kmembase <= (char *)addr && (char *)addr < kmemlimit, 270 ("free: address %p out of range", (void *)addr)); 271 kup = btokup(addr); 272 size = 1 << kup->ku_indx; 273 kbp = &bucket[kup->ku_indx]; 274 s = splmem(); 275 #ifdef INVARIANTS 276 /* 277 * Check for returns of data that do not point to the 278 * beginning of the allocation. 279 */ 280 if (size > PAGE_SIZE) 281 alloc = addrmask[BUCKETINDX(PAGE_SIZE)]; 282 else 283 alloc = addrmask[kup->ku_indx]; 284 if (((uintptr_t)(void *)addr & alloc) != 0) 285 panic("free: unaligned addr %p, size %ld, type %s, mask %ld", 286 (void *)addr, size, type->ks_shortdesc, alloc); 287 #endif /* INVARIANTS */ 288 if (size > MAXALLOCSAVE) { 289 kmem_free(kmem_map, (vm_offset_t)addr, ctob(kup->ku_pagecnt)); 290 size = kup->ku_pagecnt << PAGE_SHIFT; 291 ksp->ks_memuse -= size; 292 kup->ku_indx = 0; 293 kup->ku_pagecnt = 0; 294 if (ksp->ks_memuse + size >= ksp->ks_limit && 295 ksp->ks_memuse < ksp->ks_limit) 296 wakeup((caddr_t)ksp); 297 ksp->ks_inuse--; 298 kbp->kb_total -= 1; 299 splx(s); 300 return; 301 } 302 freep = (struct freelist *)addr; 303 #ifdef INVARIANTS 304 /* 305 * Check for multiple frees. Use a quick check to see if 306 * it looks free before laboriously searching the freelist. 307 */ 308 if (freep->spare0 == WEIRD_ADDR) { 309 fp = (struct freelist *)kbp->kb_next; 310 while (fp) { 311 if (fp->spare0 != WEIRD_ADDR) 312 panic("free: free item %p modified", fp); 313 else if (addr == (caddr_t)fp) 314 panic("free: multiple freed item %p", addr); 315 fp = (struct freelist *)fp->next; 316 } 317 } 318 /* 319 * Copy in known text to detect modification after freeing 320 * and to make it look free. Also, save the type being freed 321 * so we can list likely culprit if modification is detected 322 * when the object is reallocated. 323 */ 324 copysize = size < MAX_COPY ? size : MAX_COPY; 325 end = (long *)&((caddr_t)addr)[copysize]; 326 for (lp = (long *)addr; lp < end; lp++) 327 *lp = WEIRD_ADDR; 328 freep->type = type; 329 #endif /* INVARIANTS */ 330 kup->ku_freecnt++; 331 if (kup->ku_freecnt >= kbp->kb_elmpercl) 332 if (kup->ku_freecnt > kbp->kb_elmpercl) 333 panic("free: multiple frees"); 334 else if (kbp->kb_totalfree > kbp->kb_highwat) 335 kbp->kb_couldfree++; 336 kbp->kb_totalfree++; 337 ksp->ks_memuse -= size; 338 if (ksp->ks_memuse + size >= ksp->ks_limit && 339 ksp->ks_memuse < ksp->ks_limit) 340 wakeup((caddr_t)ksp); 341 ksp->ks_inuse--; 342 #ifdef OLD_MALLOC_MEMORY_POLICY 343 if (kbp->kb_next == NULL) 344 kbp->kb_next = addr; 345 else 346 ((struct freelist *)kbp->kb_last)->next = addr; 347 freep->next = NULL; 348 kbp->kb_last = addr; 349 #else 350 /* 351 * Return memory to the head of the queue for quick reuse. This 352 * can improve performance by improving the probability of the 353 * item being in the cache when it is reused. 354 */ 355 if (kbp->kb_next == NULL) { 356 kbp->kb_next = addr; 357 kbp->kb_last = addr; 358 freep->next = NULL; 359 } else { 360 freep->next = kbp->kb_next; 361 kbp->kb_next = addr; 362 } 363 #endif 364 splx(s); 365 } 366 367 /* 368 * Initialize the kernel memory allocator 369 */ 370 /* ARGSUSED*/ 371 static void 372 kmeminit(dummy) 373 void *dummy; 374 { 375 register long indx; 376 int npg; 377 int mem_size; 378 int xvm_kmem_size; 379 380 #if ((MAXALLOCSAVE & (MAXALLOCSAVE - 1)) != 0) 381 #error "kmeminit: MAXALLOCSAVE not power of 2" 382 #endif 383 #if (MAXALLOCSAVE > MINALLOCSIZE * 32768) 384 #error "kmeminit: MAXALLOCSAVE too big" 385 #endif 386 #if (MAXALLOCSAVE < PAGE_SIZE) 387 #error "kmeminit: MAXALLOCSAVE too small" 388 #endif 389 390 /* 391 * Try to auto-tune the kernel memory size, so that it is 392 * more applicable for a wider range of machine sizes. 393 * On an X86, a VM_KMEM_SIZE_SCALE value of 4 is good, while 394 * a VM_KMEM_SIZE of 12MB is a fair compromise. The 395 * VM_KMEM_SIZE_MAX is dependent on the maximum KVA space 396 * available, and on an X86 with a total KVA space of 256MB, 397 * try to keep VM_KMEM_SIZE_MAX at 80MB or below. 398 * 399 * Note that the kmem_map is also used by the zone allocator, 400 * so make sure that there is enough space. 401 */ 402 vm_kmem_size = VM_KMEM_SIZE; 403 mem_size = cnt.v_page_count * PAGE_SIZE; 404 405 #if defined(VM_KMEM_SIZE_SCALE) 406 if ((mem_size / VM_KMEM_SIZE_SCALE) > vm_kmem_size) 407 vm_kmem_size = mem_size / VM_KMEM_SIZE_SCALE; 408 #endif 409 410 #if defined(VM_KMEM_SIZE_MAX) 411 if (vm_kmem_size >= VM_KMEM_SIZE_MAX) 412 vm_kmem_size = VM_KMEM_SIZE_MAX; 413 #endif 414 415 /* Allow final override from the kernel environment */ 416 if (getenv_int("kern.vm.kmem.size", &xvm_kmem_size)) 417 vm_kmem_size = xvm_kmem_size; 418 419 if (vm_kmem_size > 2 * (cnt.v_page_count * PAGE_SIZE)) 420 vm_kmem_size = 2 * (cnt.v_page_count * PAGE_SIZE); 421 422 npg = (nmbufs * MSIZE + nmbclusters * MCLBYTES + vm_kmem_size) 423 / PAGE_SIZE; 424 425 kmemusage = (struct kmemusage *) kmem_alloc(kernel_map, 426 (vm_size_t)(npg * sizeof(struct kmemusage))); 427 kmem_map = kmem_suballoc(kernel_map, (vm_offset_t *)&kmembase, 428 (vm_offset_t *)&kmemlimit, (vm_size_t)(npg * PAGE_SIZE)); 429 kmem_map->system_map = 1; 430 for (indx = 0; indx < MINBUCKET + 16; indx++) { 431 if (1 << indx >= PAGE_SIZE) 432 bucket[indx].kb_elmpercl = 1; 433 else 434 bucket[indx].kb_elmpercl = PAGE_SIZE / (1 << indx); 435 bucket[indx].kb_highwat = 5 * bucket[indx].kb_elmpercl; 436 } 437 } 438 439 void 440 malloc_init(data) 441 void *data; 442 { 443 struct malloc_type *type = (struct malloc_type *)data; 444 445 if (type->ks_magic != M_MAGIC) 446 panic("malloc type lacks magic"); 447 448 if (type->ks_limit != 0) 449 return; 450 451 if (cnt.v_page_count == 0) 452 panic("malloc_init not allowed before vm init"); 453 454 /* 455 * The default limits for each malloc region is 1/2 of the 456 * malloc portion of the kmem map size. 457 */ 458 type->ks_limit = vm_kmem_size / 2; 459 type->ks_next = kmemstatistics; 460 kmemstatistics = type; 461 } 462 463 void 464 malloc_uninit(data) 465 void *data; 466 { 467 struct malloc_type *type = (struct malloc_type *)data; 468 struct malloc_type *t; 469 470 if (type->ks_magic != M_MAGIC) 471 panic("malloc type lacks magic"); 472 473 if (cnt.v_page_count == 0) 474 panic("malloc_uninit not allowed before vm init"); 475 476 if (type->ks_limit == 0) 477 panic("malloc_uninit on uninitialized type"); 478 479 if (type == kmemstatistics) 480 kmemstatistics = type->ks_next; 481 else { 482 for (t = kmemstatistics; t->ks_next != NULL; t = t->ks_next) { 483 if (t->ks_next == type) { 484 t->ks_next = type->ks_next; 485 break; 486 } 487 } 488 } 489 type->ks_next = NULL; 490 type->ks_limit = 0; 491 }
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