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: src/sys/kern/kern_malloc.c,v 1.24.2.2 1999/09/05 08:14:57 peter Exp $ 35 */ 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/proc.h> 40 #include <sys/kernel.h> 41 #include <sys/malloc.h> 42 #include <sys/mbuf.h> 43 #include <sys/vmmeter.h> 44 45 #include <vm/vm.h> 46 #include <vm/vm_param.h> 47 #include <vm/vm_kern.h> 48 #include <vm/vm_extern.h> 49 50 static void kmeminit __P((void *)); 51 SYSINIT(kmem, SI_SUB_KMEM, SI_ORDER_FIRST, kmeminit, NULL) 52 53 static struct kmembuckets bucket[MINBUCKET + 16]; 54 struct kmemstats kmemstats[M_LAST]; 55 struct kmemusage *kmemusage; 56 char *kmembase, *kmemlimit; 57 char *memname[] = INITKMEMNAMES; 58 59 #ifdef DIAGNOSTIC 60 /* 61 * This structure provides a set of masks to catch unaligned frees. 62 */ 63 static long addrmask[] = { 0, 64 0x00000001, 0x00000003, 0x00000007, 0x0000000f, 65 0x0000001f, 0x0000003f, 0x0000007f, 0x000000ff, 66 0x000001ff, 0x000003ff, 0x000007ff, 0x00000fff, 67 0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff, 68 }; 69 70 /* 71 * The WEIRD_ADDR is used as known text to copy into free objects so 72 * that modifications after frees can be detected. 73 */ 74 #define WEIRD_ADDR 0xdeadc0de 75 #define MAX_COPY 64 76 77 /* 78 * Normally the first word of the structure is used to hold the list 79 * pointer for free objects. However, when running with diagnostics, 80 * we use the third and fourth fields, so as to catch modifications 81 * in the most commonly trashed first two words. 82 */ 83 struct freelist { 84 long spare0; 85 short type; 86 long spare1; 87 caddr_t next; 88 }; 89 #else /* !DIAGNOSTIC */ 90 struct freelist { 91 caddr_t next; 92 }; 93 #endif /* DIAGNOSTIC */ 94 95 /* 96 * Allocate a block of memory 97 */ 98 void * 99 malloc(size, type, flags) 100 unsigned long size; 101 int type, flags; 102 { 103 register struct kmembuckets *kbp; 104 register struct kmemusage *kup; 105 register struct freelist *freep; 106 long indx, npg, allocsize; 107 int s; 108 caddr_t va, cp, savedlist; 109 #ifdef DIAGNOSTIC 110 long *end, *lp; 111 int copysize; 112 char *savedtype; 113 #endif 114 #ifdef KMEMSTATS 115 register struct kmemstats *ksp = &kmemstats[type]; 116 117 if (((unsigned long)type) > M_LAST) 118 panic("malloc - bogus type"); 119 #endif 120 indx = BUCKETINDX(size); 121 kbp = &bucket[indx]; 122 s = splhigh(); 123 #ifdef KMEMSTATS 124 while (ksp->ks_memuse >= ksp->ks_limit) { 125 if (flags & M_NOWAIT) { 126 splx(s); 127 return ((void *) NULL); 128 } 129 if (ksp->ks_limblocks < 65535) 130 ksp->ks_limblocks++; 131 tsleep((caddr_t)ksp, PSWP+2, memname[type], 0); 132 } 133 ksp->ks_size |= 1 << indx; 134 #endif 135 #ifdef DIAGNOSTIC 136 copysize = 1 << indx < MAX_COPY ? 1 << indx : MAX_COPY; 137 #endif 138 if (kbp->kb_next == NULL) { 139 kbp->kb_last = NULL; 140 if (size > MAXALLOCSAVE) 141 allocsize = roundup(size, PAGE_SIZE); 142 else 143 allocsize = 1 << indx; 144 npg = btoc(allocsize); 145 va = (caddr_t) kmem_malloc(kmem_map, (vm_size_t)ctob(npg), flags); 146 if (va == NULL) { 147 splx(s); 148 return ((void *) NULL); 149 } 150 #ifdef KMEMSTATS 151 kbp->kb_total += kbp->kb_elmpercl; 152 #endif 153 kup = btokup(va); 154 kup->ku_indx = indx; 155 if (allocsize > MAXALLOCSAVE) { 156 if (npg > 65535) 157 panic("malloc: allocation too large"); 158 kup->ku_pagecnt = npg; 159 #ifdef KMEMSTATS 160 ksp->ks_memuse += allocsize; 161 #endif 162 goto out; 163 } 164 #ifdef KMEMSTATS 165 kup->ku_freecnt = kbp->kb_elmpercl; 166 kbp->kb_totalfree += kbp->kb_elmpercl; 167 #endif 168 /* 169 * Just in case we blocked while allocating memory, 170 * and someone else also allocated memory for this 171 * bucket, don't assume the list is still empty. 172 */ 173 savedlist = kbp->kb_next; 174 kbp->kb_next = cp = va + (npg * PAGE_SIZE) - allocsize; 175 for (;;) { 176 freep = (struct freelist *)cp; 177 #ifdef DIAGNOSTIC 178 /* 179 * Copy in known text to detect modification 180 * after freeing. 181 */ 182 end = (long *)&cp[copysize]; 183 for (lp = (long *)cp; lp < end; lp++) 184 *lp = WEIRD_ADDR; 185 freep->type = M_FREE; 186 #endif /* DIAGNOSTIC */ 187 if (cp <= va) 188 break; 189 cp -= allocsize; 190 freep->next = cp; 191 } 192 freep->next = savedlist; 193 if (kbp->kb_last == NULL) 194 kbp->kb_last = (caddr_t)freep; 195 } 196 va = kbp->kb_next; 197 kbp->kb_next = ((struct freelist *)va)->next; 198 #ifdef DIAGNOSTIC 199 freep = (struct freelist *)va; 200 savedtype = (unsigned)freep->type < M_LAST ? 201 memname[freep->type] : "???"; 202 #if BYTE_ORDER == BIG_ENDIAN 203 freep->type = WEIRD_ADDR >> 16; 204 #endif 205 #if BYTE_ORDER == LITTLE_ENDIAN 206 freep->type = (short)WEIRD_ADDR; 207 #endif 208 if (((long)(&freep->next)) & 0x2) 209 freep->next = (caddr_t)((WEIRD_ADDR >> 16)|(WEIRD_ADDR << 16)); 210 else 211 freep->next = (caddr_t)WEIRD_ADDR; 212 end = (long *)&va[copysize]; 213 for (lp = (long *)va; lp < end; lp++) { 214 if (*lp == WEIRD_ADDR) 215 continue; 216 printf("%s %d of object %p size %ld %s %s (0x%lx != 0x%x)\n", 217 "Data modified on freelist: word", lp - (long *)va, 218 va, size, "previous type", savedtype, *lp, WEIRD_ADDR); 219 break; 220 } 221 freep->spare0 = 0; 222 #endif /* DIAGNOSTIC */ 223 #ifdef KMEMSTATS 224 kup = btokup(va); 225 if (kup->ku_indx != indx) 226 panic("malloc: wrong bucket"); 227 if (kup->ku_freecnt == 0) 228 panic("malloc: lost data"); 229 kup->ku_freecnt--; 230 kbp->kb_totalfree--; 231 ksp->ks_memuse += 1 << indx; 232 out: 233 kbp->kb_calls++; 234 ksp->ks_inuse++; 235 ksp->ks_calls++; 236 if (ksp->ks_memuse > ksp->ks_maxused) 237 ksp->ks_maxused = ksp->ks_memuse; 238 #else 239 out: 240 #endif 241 splx(s); 242 return ((void *) va); 243 } 244 245 /* 246 * Free a block of memory allocated by malloc. 247 */ 248 void 249 free(addr, type) 250 void *addr; 251 int type; 252 { 253 register struct kmembuckets *kbp; 254 register struct kmemusage *kup; 255 register struct freelist *freep; 256 long size; 257 int s; 258 #ifdef DIAGNOSTIC 259 struct freelist *fp; 260 long *end, *lp, alloc, copysize; 261 #endif 262 #ifdef KMEMSTATS 263 register struct kmemstats *ksp = &kmemstats[type]; 264 #endif 265 266 #ifdef DIAGNOSTIC 267 if ((char *)addr < kmembase || (char *)addr >= kmemlimit) { 268 panic("free: address 0x%x out of range", addr); 269 } 270 if ((u_long)type > M_LAST) { 271 panic("free: type %d out of range", type); 272 } 273 #endif 274 kup = btokup(addr); 275 size = 1 << kup->ku_indx; 276 kbp = &bucket[kup->ku_indx]; 277 s = splhigh(); 278 #ifdef DIAGNOSTIC 279 /* 280 * Check for returns of data that do not point to the 281 * beginning of the allocation. 282 */ 283 if (size > PAGE_SIZE) 284 alloc = addrmask[BUCKETINDX(PAGE_SIZE)]; 285 else 286 alloc = addrmask[kup->ku_indx]; 287 if (((u_long)addr & alloc) != 0) 288 panic("free: unaligned addr 0x%x, size %d, type %s, mask %d", 289 addr, size, memname[type], alloc); 290 #endif /* DIAGNOSTIC */ 291 if (size > MAXALLOCSAVE) { 292 kmem_free(kmem_map, (vm_offset_t)addr, ctob(kup->ku_pagecnt)); 293 #ifdef KMEMSTATS 294 size = kup->ku_pagecnt << PAGE_SHIFT; 295 ksp->ks_memuse -= size; 296 kup->ku_indx = 0; 297 kup->ku_pagecnt = 0; 298 if (ksp->ks_memuse + size >= ksp->ks_limit && 299 ksp->ks_memuse < ksp->ks_limit) 300 wakeup((caddr_t)ksp); 301 ksp->ks_inuse--; 302 kbp->kb_total -= 1; 303 #endif 304 splx(s); 305 return; 306 } 307 freep = (struct freelist *)addr; 308 #ifdef DIAGNOSTIC 309 /* 310 * Check for multiple frees. Use a quick check to see if 311 * it looks free before laboriously searching the freelist. 312 */ 313 if (freep->spare0 == WEIRD_ADDR) { 314 fp = (struct freelist *)kbp->kb_next; 315 while (fp) { 316 if (fp->spare0 != WEIRD_ADDR) { 317 printf("trashed free item %p\n", fp); 318 panic("free: free item modified"); 319 } else if (addr == (caddr_t)fp) { 320 printf("multiple freed item %p\n", addr); 321 panic("free: multiple free"); 322 } 323 fp = (struct freelist *)fp->next; 324 } 325 } 326 /* 327 * Copy in known text to detect modification after freeing 328 * and to make it look free. Also, save the type being freed 329 * so we can list likely culprit if modification is detected 330 * when the object is reallocated. 331 */ 332 copysize = size < MAX_COPY ? size : MAX_COPY; 333 end = (long *)&((caddr_t)addr)[copysize]; 334 for (lp = (long *)addr; lp < end; lp++) 335 *lp = WEIRD_ADDR; 336 freep->type = type; 337 #endif /* DIAGNOSTIC */ 338 #ifdef KMEMSTATS 339 kup->ku_freecnt++; 340 if (kup->ku_freecnt >= kbp->kb_elmpercl) 341 if (kup->ku_freecnt > kbp->kb_elmpercl) 342 panic("free: multiple frees"); 343 else if (kbp->kb_totalfree > kbp->kb_highwat) 344 kbp->kb_couldfree++; 345 kbp->kb_totalfree++; 346 ksp->ks_memuse -= size; 347 if (ksp->ks_memuse + size >= ksp->ks_limit && 348 ksp->ks_memuse < ksp->ks_limit) 349 wakeup((caddr_t)ksp); 350 ksp->ks_inuse--; 351 #endif 352 #ifdef OLD_MALLOC_MEMORY_POLICY 353 if (kbp->kb_next == NULL) 354 kbp->kb_next = addr; 355 else 356 ((struct freelist *)kbp->kb_last)->next = addr; 357 freep->next = NULL; 358 kbp->kb_last = addr; 359 #else 360 /* 361 * Return memory to the head of the queue for quick reuse. This 362 * can improve performance by improving the probability of the 363 * item being in the cache when it is reused. 364 */ 365 if (kbp->kb_next == NULL) { 366 kbp->kb_next = addr; 367 kbp->kb_last = addr; 368 freep->next = NULL; 369 } else { 370 freep->next = kbp->kb_next; 371 kbp->kb_next = addr; 372 } 373 #endif 374 splx(s); 375 } 376 377 /* 378 * Initialize the kernel memory allocator 379 */ 380 /* ARGSUSED*/ 381 static void 382 kmeminit(dummy) 383 void *dummy; 384 { 385 register long indx; 386 int npg; 387 388 #if ((MAXALLOCSAVE & (MAXALLOCSAVE - 1)) != 0) 389 #error "kmeminit: MAXALLOCSAVE not power of 2" 390 #endif 391 #if (MAXALLOCSAVE > MINALLOCSIZE * 32768) 392 #error "kmeminit: MAXALLOCSAVE too big" 393 #endif 394 #if (MAXALLOCSAVE < PAGE_SIZE) 395 #error "kmeminit: MAXALLOCSAVE too small" 396 #endif 397 npg = (nmbufs * MSIZE + nmbclusters * MCLBYTES + VM_KMEM_SIZE) 398 / PAGE_SIZE; 399 400 kmemusage = (struct kmemusage *) kmem_alloc(kernel_map, 401 (vm_size_t)(npg * sizeof(struct kmemusage))); 402 kmem_map = kmem_suballoc(kernel_map, (vm_offset_t *)&kmembase, 403 (vm_offset_t *)&kmemlimit, (vm_size_t)(npg * PAGE_SIZE), 404 FALSE); 405 #ifdef KMEMSTATS 406 for (indx = 0; indx < MINBUCKET + 16; indx++) { 407 if (1 << indx >= PAGE_SIZE) 408 bucket[indx].kb_elmpercl = 1; 409 else 410 bucket[indx].kb_elmpercl = PAGE_SIZE / (1 << indx); 411 bucket[indx].kb_highwat = 5 * bucket[indx].kb_elmpercl; 412 } 413 /* 414 * Limit maximum memory for each type to 60% of malloc area size or 415 * 60% of physical memory, whichever is smaller. 416 */ 417 for (indx = 0; indx < M_LAST; indx++) { 418 kmemstats[indx].ks_limit = min(cnt.v_page_count * PAGE_SIZE, 419 (npg * PAGE_SIZE - nmbclusters * MCLBYTES 420 - nmbufs * MSIZE)) * 6 / 10; 421 } 422 #endif 423 }
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