| 1 |
#ifndef lint |
| 2 |
static const char RCSid[] = "$Id$"; |
| 3 |
#endif |
| 4 |
/* |
| 5 |
* Fast malloc for memory hogs and VM environments. |
| 6 |
* Performs a minimum of searching through free lists. |
| 7 |
* malloc(), realloc() and free() use buckets |
| 8 |
* containing blocks in powers of two, similar to CIT routines. |
| 9 |
* bfree() puts memory from any source into malloc free lists. |
| 10 |
* bmalloc() doesn't keep track of free lists -- it's usually |
| 11 |
* just a buffered call to sbrk(2). However, bmalloc will |
| 12 |
* call mscrounge() if sbrk fails. |
| 13 |
* mscrounge() returns whatever free memory it can find to satisfy the |
| 14 |
* request along with the number of bytes (modified). |
| 15 |
* mcompact() takes the same arguments as mscrounge() (and is in fact |
| 16 |
* called by mscrounge() under dire circumstances), but it uses |
| 17 |
* memory compaction to return a larger block. (MCOMP) |
| 18 |
* |
| 19 |
* Greg Ward Lawrence Berkeley Laboratory |
| 20 |
*/ |
| 21 |
|
| 22 |
#include "copyright.h" |
| 23 |
|
| 24 |
#include <errno.h> |
| 25 |
|
| 26 |
#ifndef BSD |
| 27 |
#define bcopy(s,d,n) (void)memcpy(d,s,n) |
| 28 |
#define bzero(d,n) (void)memset(d,0,n) |
| 29 |
#endif |
| 30 |
|
| 31 |
#ifdef MSTATS |
| 32 |
#include <stdio.h> |
| 33 |
static unsigned b_nsbrked = 0; |
| 34 |
static unsigned b_nalloced = 0; |
| 35 |
static unsigned b_nfreed = 0; |
| 36 |
static unsigned b_nscrounged = 0; |
| 37 |
static unsigned b_ncompacted = 0; |
| 38 |
static unsigned m_nalloced = 0; |
| 39 |
static unsigned m_nfreed = 0; |
| 40 |
static unsigned m_nwasted = 0; |
| 41 |
#else |
| 42 |
#define NULL 0 |
| 43 |
#endif |
| 44 |
|
| 45 |
#ifndef ALIGNT |
| 46 |
#define ALIGNT int /* align type */ |
| 47 |
#endif |
| 48 |
#define BYTES_WORD sizeof(ALIGNT) |
| 49 |
|
| 50 |
#ifndef MAXINCR |
| 51 |
#define MAXINCR (1<<16) /* largest sbrk(2) increment */ |
| 52 |
#endif |
| 53 |
/* malloc free lists */ |
| 54 |
typedef union m_head { |
| 55 |
union m_head *next; |
| 56 |
struct { |
| 57 |
short magic; |
| 58 |
short bucket; |
| 59 |
} a; |
| 60 |
ALIGNT dummy; |
| 61 |
} M_HEAD; |
| 62 |
|
| 63 |
#define MAGIC 0x1a2 /* magic number for allocated memory */ |
| 64 |
|
| 65 |
#define FIRSTBUCKET 3 |
| 66 |
#define NBUCKETS 30 |
| 67 |
|
| 68 |
static M_HEAD *free_list[NBUCKETS]; |
| 69 |
|
| 70 |
static ALIGNT dummy_mem; |
| 71 |
|
| 72 |
static char *memlim[2]; |
| 73 |
|
| 74 |
#define DUMMYLOC ((char *)&dummy_mem) |
| 75 |
|
| 76 |
#define BADPTR(p) ((p) < memlim[0] | (p) >= memlim[1]) |
| 77 |
|
| 78 |
#ifdef MCOMP /* memory compaction routines */ |
| 79 |
static char seedtab[1024]; /* seed for compaction table */ |
| 80 |
|
| 81 |
static struct mblk { |
| 82 |
char *ptr; /* pointer to memory block */ |
| 83 |
unsigned siz; /* size of memory block */ |
| 84 |
} cptab = {seedtab, sizeof(seedtab)}; |
| 85 |
|
| 86 |
#define mtab(mb) ((struct mblk *)(mb)->ptr) |
| 87 |
#define mtablen(mb) ((mb)->siz/sizeof(struct mblk)) |
| 88 |
|
| 89 |
|
| 90 |
static int |
| 91 |
mbcmp(m1, m2) /* compare memory block locations */ |
| 92 |
register struct mblk *m1, *m2; |
| 93 |
{ |
| 94 |
/* put empty blocks at end */ |
| 95 |
if (m1->siz == 0) |
| 96 |
return(m2->siz == 0 ? 0 : 1); |
| 97 |
if (m2->siz == 0) |
| 98 |
return(-1); |
| 99 |
/* otherwise, ascending order */ |
| 100 |
return(m1->ptr - m2->ptr); |
| 101 |
} |
| 102 |
|
| 103 |
|
| 104 |
int |
| 105 |
compactfree() /* compact free lists (moving to table) */ |
| 106 |
{ |
| 107 |
register struct mblk *tp; |
| 108 |
register int bucket; |
| 109 |
unsigned n, bsiz, ncomp; |
| 110 |
/* fill table from free lists */ |
| 111 |
tp = mtab(&cptab); n = mtablen(&cptab); |
| 112 |
bucket = NBUCKETS-1; bsiz = 1<<(NBUCKETS-1); |
| 113 |
ncomp = 0; |
| 114 |
for ( ; ; ) { |
| 115 |
while (tp->siz) { /* find empty slot */ |
| 116 |
if (--n == 0) |
| 117 |
goto loopexit; |
| 118 |
tp++; |
| 119 |
} |
| 120 |
while (free_list[bucket] == NULL) { /* find block */ |
| 121 |
if (--bucket < FIRSTBUCKET) |
| 122 |
goto loopexit; |
| 123 |
bsiz >>= 1; |
| 124 |
} |
| 125 |
tp->ptr = (char *)free_list[bucket]; |
| 126 |
ncomp += (tp->siz = bsiz + sizeof(M_HEAD)); |
| 127 |
free_list[bucket] = free_list[bucket]->next; |
| 128 |
} |
| 129 |
loopexit: |
| 130 |
if (ncomp == 0) |
| 131 |
return(0); /* nothing new to compact */ |
| 132 |
#ifdef MSTATS |
| 133 |
b_ncompacted += ncomp; |
| 134 |
#endif |
| 135 |
tp = mtab(&cptab); n = mtablen(&cptab); /* sort table */ |
| 136 |
qsort((char *)tp, n, sizeof(struct mblk), mbcmp); |
| 137 |
ncomp = 0; /* collect blocks */ |
| 138 |
while (--n && tp[1].siz) { |
| 139 |
if (tp[0].ptr + tp[0].siz == tp[1].ptr) { |
| 140 |
tp[1].ptr = tp[0].ptr; |
| 141 |
tp[1].siz += tp[0].siz; |
| 142 |
ncomp += tp[0].siz; |
| 143 |
tp[0].siz = 0; |
| 144 |
} |
| 145 |
tp++; |
| 146 |
} |
| 147 |
return(ncomp); |
| 148 |
} |
| 149 |
|
| 150 |
|
| 151 |
char * |
| 152 |
mcompact(np) /* compact free lists to satisfy request */ |
| 153 |
unsigned *np; |
| 154 |
{ |
| 155 |
struct mblk *tab; |
| 156 |
unsigned tablen; |
| 157 |
register struct mblk *bp, *big; |
| 158 |
|
| 159 |
for ( ; ; ) { |
| 160 |
/* compact free lists */ |
| 161 |
while (compactfree()) |
| 162 |
; |
| 163 |
/* find largest block */ |
| 164 |
tab = mtab(&cptab); tablen = mtablen(&cptab); |
| 165 |
big = tab; |
| 166 |
bp = tab + tablen; |
| 167 |
while (--bp > tab) |
| 168 |
if (bp->siz > big->siz) |
| 169 |
big = bp; |
| 170 |
if (big->siz >= *np) { /* big enough? */ |
| 171 |
*np = big->siz; |
| 172 |
big->siz = 0; /* remove from table */ |
| 173 |
return(big->ptr); /* return it */ |
| 174 |
} |
| 175 |
if (mtablen(big) <= tablen) { |
| 176 |
*np = 0; /* cannot grow table */ |
| 177 |
return(NULL); /* report failure */ |
| 178 |
} |
| 179 |
/* enlarge table, free old one */ |
| 180 |
mtab(big)[0].ptr = cptab.ptr; |
| 181 |
mtab(big)[0].siz = cptab.siz; |
| 182 |
cptab.ptr = big->ptr; |
| 183 |
cptab.siz = big->siz; |
| 184 |
big->siz = 0; /* clear and copy */ |
| 185 |
bcopy((char *)tab, (char *)(mtab(&cptab)+1), |
| 186 |
tablen*sizeof(struct mblk)); |
| 187 |
bzero((char *)(mtab(&cptab)+tablen+1), |
| 188 |
(mtablen(&cptab)-tablen-1)*sizeof(struct mblk)); |
| 189 |
} /* next round */ |
| 190 |
} |
| 191 |
#endif /* MCOMP */ |
| 192 |
|
| 193 |
|
| 194 |
char * |
| 195 |
mscrounge(np) /* search free lists to satisfy request */ |
| 196 |
register unsigned *np; |
| 197 |
{ |
| 198 |
char *p; |
| 199 |
register int bucket; |
| 200 |
register unsigned bsiz; |
| 201 |
|
| 202 |
for (bucket = FIRSTBUCKET, bsiz = 1<<FIRSTBUCKET; |
| 203 |
bucket < NBUCKETS; bucket++, bsiz <<= 1) |
| 204 |
if (free_list[bucket] != NULL && bsiz+sizeof(M_HEAD) >= *np) { |
| 205 |
*np = bsiz+sizeof(M_HEAD); |
| 206 |
p = (char *)free_list[bucket]; |
| 207 |
free_list[bucket] = free_list[bucket]->next; |
| 208 |
#ifdef MSTATS |
| 209 |
b_nscrounged += *np; |
| 210 |
#endif |
| 211 |
return(p); |
| 212 |
} |
| 213 |
#ifdef MCOMP |
| 214 |
return(mcompact(np)); /* try compaction */ |
| 215 |
#else |
| 216 |
*np = 0; |
| 217 |
return(NULL); |
| 218 |
#endif |
| 219 |
} |
| 220 |
|
| 221 |
|
| 222 |
char * |
| 223 |
bmalloc(n) /* allocate a block of n bytes, sans header */ |
| 224 |
register unsigned n; |
| 225 |
{ |
| 226 |
extern char *sbrk(); |
| 227 |
static unsigned pagesz = 0; |
| 228 |
static unsigned amnt; |
| 229 |
static char *bpos; |
| 230 |
static unsigned nrem; |
| 231 |
unsigned thisamnt; |
| 232 |
register char *p; |
| 233 |
|
| 234 |
if (pagesz == 0) { /* initialize */ |
| 235 |
pagesz = amnt = getpagesize(); |
| 236 |
nrem = (int)sbrk(0); /* page align break */ |
| 237 |
nrem = pagesz - (nrem&(pagesz-1)); |
| 238 |
bpos = sbrk(nrem); |
| 239 |
if ((int)bpos == -1) |
| 240 |
return(NULL); |
| 241 |
#ifdef MSTATS |
| 242 |
b_nsbrked += nrem; |
| 243 |
#endif |
| 244 |
bpos += nrem & (BYTES_WORD-1); /* align pointer */ |
| 245 |
nrem &= ~(BYTES_WORD-1); |
| 246 |
memlim[0] = bpos; |
| 247 |
memlim[1] = bpos + nrem; |
| 248 |
} |
| 249 |
|
| 250 |
n = (n+(BYTES_WORD-1))&~(BYTES_WORD-1); /* word align rqst. */ |
| 251 |
|
| 252 |
if (n > nrem) { /* need more core */ |
| 253 |
tryagain: |
| 254 |
if (n > amnt) { /* big chunk */ |
| 255 |
thisamnt = (n+(pagesz-1))&~(pagesz-1); |
| 256 |
if (thisamnt <= MAXINCR) /* increase amnt */ |
| 257 |
amnt = thisamnt; |
| 258 |
} else |
| 259 |
thisamnt = amnt; |
| 260 |
p = sbrk(thisamnt); |
| 261 |
if ((int)p == -1) { /* uh-oh, ENOMEM */ |
| 262 |
errno = 0; /* call cavalry */ |
| 263 |
if (thisamnt >= n+pagesz) { |
| 264 |
amnt = pagesz; /* minimize request */ |
| 265 |
goto tryagain; |
| 266 |
} |
| 267 |
thisamnt = n; |
| 268 |
p = mscrounge(&thisamnt); /* search free lists */ |
| 269 |
if (p == NULL) { /* we're really out */ |
| 270 |
errno = ENOMEM; |
| 271 |
return(NULL); |
| 272 |
} |
| 273 |
} |
| 274 |
#ifdef MSTATS |
| 275 |
else b_nsbrked += thisamnt; |
| 276 |
#endif |
| 277 |
if (p != bpos+nrem) { /* not an increment */ |
| 278 |
bfree(bpos, nrem); /* free what we have */ |
| 279 |
bpos = p; |
| 280 |
nrem = thisamnt; |
| 281 |
} else /* otherwise tack on */ |
| 282 |
nrem += thisamnt; |
| 283 |
if (bpos < memlim[0]) |
| 284 |
memlim[0] = bpos; |
| 285 |
if (bpos + nrem > memlim[1]) |
| 286 |
memlim[1] = bpos + nrem; |
| 287 |
} |
| 288 |
p = bpos; |
| 289 |
bpos += n; /* advance */ |
| 290 |
nrem -= n; |
| 291 |
#ifdef MSTATS |
| 292 |
b_nalloced += n; |
| 293 |
#endif |
| 294 |
return(p); |
| 295 |
} |
| 296 |
|
| 297 |
|
| 298 |
bfree(p, n) /* free n bytes of random memory */ |
| 299 |
register char *p; |
| 300 |
register unsigned n; |
| 301 |
{ |
| 302 |
register int bucket; |
| 303 |
register unsigned bsiz; |
| 304 |
|
| 305 |
if (n < 1<<FIRSTBUCKET || p == NULL) |
| 306 |
return; |
| 307 |
#ifdef MSTATS |
| 308 |
b_nfreed += n; |
| 309 |
#endif |
| 310 |
/* align pointer */ |
| 311 |
bsiz = BYTES_WORD - ((unsigned)p&(BYTES_WORD-1)); |
| 312 |
if (bsiz < BYTES_WORD) { |
| 313 |
p += bsiz; |
| 314 |
n -= bsiz; |
| 315 |
} |
| 316 |
if (p < memlim[0]) |
| 317 |
memlim[0] = p; |
| 318 |
if (p + n > memlim[1]) |
| 319 |
memlim[1] = p + n; |
| 320 |
/* fill big buckets first */ |
| 321 |
for (bucket = NBUCKETS-1, bsiz = 1<<(NBUCKETS-1); |
| 322 |
bucket >= FIRSTBUCKET; bucket--, bsiz >>= 1) |
| 323 |
if (n >= bsiz+sizeof(M_HEAD)) { |
| 324 |
((M_HEAD *)p)->next = free_list[bucket]; |
| 325 |
free_list[bucket] = (M_HEAD *)p; |
| 326 |
p += bsiz+sizeof(M_HEAD); |
| 327 |
n -= bsiz+sizeof(M_HEAD); |
| 328 |
} |
| 329 |
} |
| 330 |
|
| 331 |
|
| 332 |
char * |
| 333 |
malloc(n) /* allocate n bytes of memory */ |
| 334 |
unsigned n; |
| 335 |
{ |
| 336 |
register M_HEAD *mp; |
| 337 |
register int bucket; |
| 338 |
register unsigned bsiz; |
| 339 |
/* don't return NULL on 0 request */ |
| 340 |
if (n == 0) |
| 341 |
return(DUMMYLOC); |
| 342 |
/* find first bucket that fits */ |
| 343 |
for (bucket = FIRSTBUCKET, bsiz = 1<<FIRSTBUCKET; |
| 344 |
bucket < NBUCKETS; bucket++, bsiz <<= 1) |
| 345 |
if (bsiz >= n) |
| 346 |
break; |
| 347 |
if (bucket >= NBUCKETS) { |
| 348 |
errno = EINVAL; |
| 349 |
return(NULL); |
| 350 |
} |
| 351 |
if (free_list[bucket] == NULL) { /* need more core */ |
| 352 |
mp = (M_HEAD *)bmalloc(bsiz+sizeof(M_HEAD)); |
| 353 |
if (mp == NULL) |
| 354 |
return(NULL); |
| 355 |
} else { /* got it */ |
| 356 |
mp = free_list[bucket]; |
| 357 |
free_list[bucket] = mp->next; |
| 358 |
} |
| 359 |
#ifdef MSTATS |
| 360 |
m_nalloced += bsiz + sizeof(M_HEAD); |
| 361 |
m_nwasted += bsiz + sizeof(M_HEAD) - n; |
| 362 |
#endif |
| 363 |
mp->a.magic = MAGIC; /* tag block */ |
| 364 |
mp->a.bucket = bucket; |
| 365 |
return((char *)(mp+1)); |
| 366 |
} |
| 367 |
|
| 368 |
|
| 369 |
char * |
| 370 |
realloc(op, n) /* reallocate memory using malloc() */ |
| 371 |
register char *op; |
| 372 |
unsigned n; |
| 373 |
{ |
| 374 |
char *p; |
| 375 |
register unsigned on; |
| 376 |
/* get old size */ |
| 377 |
if (op != DUMMYLOC && !BADPTR(op) && |
| 378 |
((M_HEAD *)op-1)->a.magic == MAGIC) |
| 379 |
on = 1 << ((M_HEAD *)op-1)->a.bucket; |
| 380 |
else |
| 381 |
on = 0; |
| 382 |
if (n <= on && (n > on>>1 || on == 1<<FIRSTBUCKET)) |
| 383 |
return(op); /* same bucket */ |
| 384 |
if ((p = malloc(n)) == NULL) |
| 385 |
return(n<=on ? op : NULL); |
| 386 |
if (on) { |
| 387 |
bcopy(op, p, n>on ? on : n); |
| 388 |
free(op); |
| 389 |
} |
| 390 |
return(p); |
| 391 |
} |
| 392 |
|
| 393 |
|
| 394 |
free(p) /* free memory allocated by malloc */ |
| 395 |
char *p; |
| 396 |
{ |
| 397 |
register M_HEAD *mp; |
| 398 |
register int bucket; |
| 399 |
|
| 400 |
if (p == DUMMYLOC) |
| 401 |
return(1); |
| 402 |
if (BADPTR(p)) |
| 403 |
goto invalid; |
| 404 |
mp = (M_HEAD *)p - 1; |
| 405 |
if (mp->a.magic != MAGIC) /* sanity check */ |
| 406 |
goto invalid; |
| 407 |
bucket = mp->a.bucket; |
| 408 |
if (bucket < FIRSTBUCKET | bucket >= NBUCKETS) |
| 409 |
goto invalid; |
| 410 |
mp->next = free_list[bucket]; |
| 411 |
free_list[bucket] = mp; |
| 412 |
#ifdef MSTATS |
| 413 |
m_nfreed += (1 << bucket) + sizeof(M_HEAD); |
| 414 |
#endif |
| 415 |
return(1); |
| 416 |
invalid: |
| 417 |
errno = EINVAL; |
| 418 |
return(0); |
| 419 |
} |
| 420 |
|
| 421 |
|
| 422 |
#ifdef MSTATS |
| 423 |
printmemstats(fp) /* print memory statistics to stream */ |
| 424 |
FILE *fp; |
| 425 |
{ |
| 426 |
register int i; |
| 427 |
int n; |
| 428 |
register M_HEAD *mp; |
| 429 |
unsigned int total = 0; |
| 430 |
|
| 431 |
fprintf(fp, "Memory statistics:\n"); |
| 432 |
fprintf(fp, "\tbmalloc: %d bytes from sbrk\n", b_nsbrked); |
| 433 |
fprintf(fp, "\tbmalloc: %d bytes allocated\n", b_nalloced); |
| 434 |
fprintf(fp, "\tbmalloc: %d bytes freed\n", b_nfreed); |
| 435 |
fprintf(fp, "\tbmalloc: %d bytes scrounged\n", b_nscrounged); |
| 436 |
fprintf(fp, "\tbmalloc: %d bytes compacted\n", b_ncompacted); |
| 437 |
fprintf(fp, "\tmalloc: %d bytes allocated\n", m_nalloced); |
| 438 |
fprintf(fp, "\tmalloc: %d bytes wasted (%.1f%%)\n", m_nwasted, |
| 439 |
100.0*m_nwasted/m_nalloced); |
| 440 |
fprintf(fp, "\tmalloc: %d bytes freed\n", m_nfreed); |
| 441 |
for (i = NBUCKETS-1; i >= FIRSTBUCKET; i--) { |
| 442 |
n = 0; |
| 443 |
for (mp = free_list[i]; mp != NULL; mp = mp->next) |
| 444 |
n++; |
| 445 |
if (n) { |
| 446 |
fprintf(fp, "\t%d * %u\n", n, 1<<i); |
| 447 |
total += n * ((1<<i) + sizeof(M_HEAD)); |
| 448 |
} |
| 449 |
} |
| 450 |
fprintf(fp, "\t %u total bytes in free list\n", total); |
| 451 |
} |
| 452 |
#endif |
