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a0d0e21e 1/* malloc.c
8d063cd8 2 *
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3 */
4
5#ifndef lint
1944739a
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6# if defined(DEBUGGING) && !defined(NO_RCHECK)
7# define RCHECK
8# endif
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9/*
10 * malloc.c (Caltech) 2/21/82
11 * Chris Kingsley, kingsley@cit-20.
12 *
13 * This is a very fast storage allocator. It allocates blocks of a small
14 * number of different sizes, and keeps free lists of each size. Blocks that
15 * don't exactly fit are passed up to the next larger size. In this
16 * implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long.
cf5c4ad8 17 * If PACK_MALLOC is defined, small blocks are 2^n bytes long.
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18 * This is designed for use in a program that uses vast quantities of memory,
19 * but bombs when it runs out.
20 */
21
135863df 22#include "EXTERN.h"
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23#include "perl.h"
24
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25#ifdef DEBUGGING
26#undef DEBUG_m
27#define DEBUG_m(a) if (debug & 128) a
28#endif
29
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30/* I don't much care whether these are defined in sys/types.h--LAW */
31
32#define u_char unsigned char
33#define u_int unsigned int
34#define u_short unsigned short
8d063cd8 35
cf5c4ad8 36/* 286 and atarist like big chunks, which gives too much overhead. */
37#if (defined(RCHECK) || defined(I286) || defined(atarist)) && defined(PACK_MALLOC)
38#undef PACK_MALLOC
39#endif
40
41
8d063cd8 42/*
cf5c4ad8 43 * The description below is applicable if PACK_MALLOC is not defined.
44 *
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45 * The overhead on a block is at least 4 bytes. When free, this space
46 * contains a pointer to the next free block, and the bottom two bits must
47 * be zero. When in use, the first byte is set to MAGIC, and the second
48 * byte is the size index. The remaining bytes are for alignment.
49 * If range checking is enabled and the size of the block fits
50 * in two bytes, then the top two bytes hold the size of the requested block
51 * plus the range checking words, and the header word MINUS ONE.
52 */
53union overhead {
54 union overhead *ov_next; /* when free */
85e6fe83 55#if MEM_ALIGNBYTES > 4
c623bd54 56 double strut; /* alignment problems */
a687059c 57#endif
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58 struct {
59 u_char ovu_magic; /* magic number */
60 u_char ovu_index; /* bucket # */
61#ifdef RCHECK
62 u_short ovu_size; /* actual block size */
63 u_int ovu_rmagic; /* range magic number */
64#endif
65 } ovu;
66#define ov_magic ovu.ovu_magic
67#define ov_index ovu.ovu_index
68#define ov_size ovu.ovu_size
69#define ov_rmagic ovu.ovu_rmagic
70};
71
760ac839 72#ifdef DEBUGGING
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73static void botch _((char *s));
74#endif
75static void morecore _((int bucket));
76static int findbucket _((union overhead *freep, int srchlen));
77
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78#define MAGIC 0xff /* magic # on accounting info */
79#define RMAGIC 0x55555555 /* magic # on range info */
80#ifdef RCHECK
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81# define RSLOP sizeof (u_int)
82# ifdef TWO_POT_OPTIMIZE
83# define MAX_SHORT_BUCKET 12
84# else
85# define MAX_SHORT_BUCKET 13
86# endif
8d063cd8 87#else
c2a5c2d2 88# define RSLOP 0
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89#endif
90
cf5c4ad8 91#ifdef PACK_MALLOC
92/*
93 * In this case it is assumed that if we do sbrk() in 2K units, we
94 * will get 2K aligned blocks. The bucket number of the given subblock is
95 * on the boundary of 2K block which contains the subblock.
96 * Several following bytes contain the magic numbers for the subblocks
97 * in the block.
98 *
99 * Sizes of chunks are powers of 2 for chunks in buckets <=
100 * MAX_PACKED, after this they are (2^n - sizeof(union overhead)) (to
101 * get alignment right).
102 *
103 * We suppose that starts of all the chunks in a 2K block are in
104 * different 2^n-byte-long chunks. If the top of the last chunk is
105 * aligned on a boundary of 2K block, this means that
106 * sizeof(union overhead)*"number of chunks" < 2^n, or
107 * sizeof(union overhead)*2K < 4^n, or n > 6 + log2(sizeof()/2)/2, if a
108 * chunk of size 2^n - overhead is used. Since this rules out n = 7
109 * for 8 byte alignment, we specialcase allocation of the first of 16
110 * 128-byte-long chunks.
111 *
112 * Note that with the above assumption we automatically have enough
113 * place for MAGIC at the start of 2K block. Note also that we
114 * overlay union overhead over the chunk, thus the start of the chunk
115 * is immediately overwritten after freeing.
116 */
117# define MAX_PACKED 6
118# define MAX_2_POT_ALGO ((1<<(MAX_PACKED + 1)) - M_OVERHEAD)
119# define TWOK_MASK ((1<<11) - 1)
ff68c719 120# define TWOK_MASKED(x) ((u_int)(x) & ~TWOK_MASK)
121# define TWOK_SHIFT(x) ((u_int)(x) & TWOK_MASK)
cf5c4ad8 122# define OV_INDEXp(block) ((u_char*)(TWOK_MASKED(block)))
123# define OV_INDEX(block) (*OV_INDEXp(block))
124# define OV_MAGIC(block,bucket) (*(OV_INDEXp(block) + \
125 (TWOK_SHIFT(block)>>(bucket + 3)) + \
126 (bucket > MAX_NONSHIFT ? 1 : 0)))
127# define CHUNK_SHIFT 0
128
129static u_char n_blks[11 - 3] = {224, 120, 62, 31, 16, 8, 4, 2};
130static u_short blk_shift[11 - 3] = {256, 128, 64, 32,
131 16*sizeof(union overhead),
132 8*sizeof(union overhead),
133 4*sizeof(union overhead),
134 2*sizeof(union overhead),
135# define MAX_NONSHIFT 2 /* Shift 64 greater than chunk 32. */
136};
137
cf5c4ad8 138#else /* !PACK_MALLOC */
139
140# define OV_MAGIC(block,bucket) (block)->ov_magic
141# define OV_INDEX(block) (block)->ov_index
142# define CHUNK_SHIFT 1
143#endif /* !PACK_MALLOC */
144
145# define M_OVERHEAD (sizeof(union overhead) + RSLOP)
146
8d063cd8 147/*
55497cff 148 * Big allocations are often of the size 2^n bytes. To make them a
149 * little bit better, make blocks of size 2^n+pagesize for big n.
150 */
151
152#ifdef TWO_POT_OPTIMIZE
153
5f05dabc 154# ifndef PERL_PAGESIZE
155# define PERL_PAGESIZE 4096
156# endif
157# ifndef FIRST_BIG_TWO_POT
158# define FIRST_BIG_TWO_POT 14 /* 16K */
159# endif
55497cff 160# define FIRST_BIG_BLOCK (1<<FIRST_BIG_TWO_POT) /* 16K */
161/* If this value or more, check against bigger blocks. */
162# define FIRST_BIG_BOUND (FIRST_BIG_BLOCK - M_OVERHEAD)
163/* If less than this value, goes into 2^n-overhead-block. */
164# define LAST_SMALL_BOUND ((FIRST_BIG_BLOCK>>1) - M_OVERHEAD)
165
166#endif /* TWO_POT_OPTIMIZE */
167
72e5b9db 168#if defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)
55497cff 169
170#ifndef BIG_SIZE
171# define BIG_SIZE (1<<16) /* 64K */
172#endif
173
174static char *emergency_buffer;
175static MEM_SIZE emergency_buffer_size;
176
177static char *
178emergency_sbrk(size)
179 MEM_SIZE size;
180{
181 if (size >= BIG_SIZE) {
182 /* Give the possibility to recover: */
183 die("Out of memory during request for %i bytes", size);
184 /* croak may eat too much memory. */
185 }
186
187 if (!emergency_buffer) {
188 /* First offense, give a possibility to recover by dieing. */
189 /* No malloc involved here: */
190 GV **gvp = (GV**)hv_fetch(defstash, "^M", 2, 0);
191 SV *sv;
192 char *pv;
193
194 if (!gvp) gvp = (GV**)hv_fetch(defstash, "\015", 1, 0);
195 if (!gvp || !(sv = GvSV(*gvp)) || !SvPOK(sv)
196 || (SvLEN(sv) < (1<<11) - M_OVERHEAD))
197 return (char *)-1; /* Now die die die... */
198
199 /* Got it, now detach SvPV: */
bbce6d69 200 pv = SvPV(sv, na);
55497cff 201 /* Check alignment: */
ff68c719 202 if (((u_int)(pv - M_OVERHEAD)) & ((1<<11) - 1)) {
55497cff 203 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
bbce6d69 204 return (char *)-1; /* die die die */
55497cff 205 }
206
207 emergency_buffer = pv - M_OVERHEAD;
208 emergency_buffer_size = SvLEN(sv) + M_OVERHEAD;
209 SvPOK_off(sv);
210 SvREADONLY_on(sv);
211 die("Out of memory!"); /* croak may eat too much memory. */
ff68c719 212 }
213 else if (emergency_buffer_size >= size) {
55497cff 214 emergency_buffer_size -= size;
215 return emergency_buffer + emergency_buffer_size;
216 }
217
218 return (char *)-1; /* poor guy... */
219}
220
72e5b9db 221#else /* !(defined(TWO_POT_OPTIMIZE) && defined(PERL_CORE)) */
55497cff 222# define emergency_sbrk(size) -1
72e5b9db 223#endif /* !(defined(TWO_POT_OPTIMIZE) && defined(PERL_CORE)) */
55497cff 224
225/*
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226 * nextf[i] is the pointer to the next free block of size 2^(i+3). The
227 * smallest allocatable block is 8 bytes. The overhead information
228 * precedes the data area returned to the user.
229 */
230#define NBUCKETS 30
231static union overhead *nextf[NBUCKETS];
cf5c4ad8 232
233#ifdef USE_PERL_SBRK
234#define sbrk(a) Perl_sbrk(a)
235char * Perl_sbrk _((int size));
236#else
8d063cd8 237extern char *sbrk();
cf5c4ad8 238#endif
8d063cd8 239
c07a80fd 240#ifdef DEBUGGING_MSTATS
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241/*
242 * nmalloc[i] is the difference between the number of mallocs and frees
243 * for a given block size.
244 */
245static u_int nmalloc[NBUCKETS];
5f05dabc 246static u_int goodsbrk;
247static u_int sbrk_slack;
248static u_int start_slack;
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249#endif
250
760ac839 251#ifdef DEBUGGING
4dfc412b 252#define ASSERT(p) if (!(p)) botch(STRINGIFY(p)); else
ee0007ab 253static void
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254botch(s)
255 char *s;
256{
4dfc412b 257 PerlIO_printf(PerlIO_stderr(), "assertion botched: %s\n", s);
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258 abort();
259}
260#else
261#define ASSERT(p)
262#endif
263
2304df62 264Malloc_t
8d063cd8 265malloc(nbytes)
ee0007ab 266 register MEM_SIZE nbytes;
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267{
268 register union overhead *p;
269 register int bucket = 0;
ee0007ab 270 register MEM_SIZE shiftr;
8d063cd8 271
c2a5c2d2 272#if defined(DEBUGGING) || defined(RCHECK)
ee0007ab 273 MEM_SIZE size = nbytes;
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274#endif
275
043bf814 276#ifdef PERL_CORE
55497cff 277#ifdef HAS_64K_LIMIT
45d8adaa 278 if (nbytes > 0xffff) {
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279 PerlIO_printf(PerlIO_stderr(),
280 "Allocation too large: %lx\n", (long)nbytes);
79072805 281 my_exit(1);
45d8adaa 282 }
55497cff 283#endif /* HAS_64K_LIMIT */
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284#ifdef DEBUGGING
285 if ((long)nbytes < 0)
043bf814 286 croak("panic: malloc");
45d8adaa 287#endif
55497cff 288#endif /* PERL_CORE */
45d8adaa 289
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290 /*
291 * Convert amount of memory requested into
292 * closest block size stored in hash buckets
293 * which satisfies request. Account for
294 * space used per block for accounting.
295 */
cf5c4ad8 296#ifdef PACK_MALLOC
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297 if (nbytes == 0)
298 nbytes = 1;
299 else if (nbytes > MAX_2_POT_ALGO)
cf5c4ad8 300#endif
043bf814 301 {
55497cff 302#ifdef TWO_POT_OPTIMIZE
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303 if (nbytes >= FIRST_BIG_BOUND)
304 nbytes -= PERL_PAGESIZE;
55497cff 305#endif
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306 nbytes += M_OVERHEAD;
307 nbytes = (nbytes + 3) &~ 3;
cf5c4ad8 308 }
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309 shiftr = (nbytes - 1) >> 2;
310 /* apart from this loop, this is O(1) */
311 while (shiftr >>= 1)
312 bucket++;
313 /*
314 * If nothing in hash bucket right now,
315 * request more memory from the system.
316 */
317 if (nextf[bucket] == NULL)
318 morecore(bucket);
45d8adaa 319 if ((p = (union overhead *)nextf[bucket]) == NULL) {
55497cff 320#ifdef PERL_CORE
ee0007ab 321 if (!nomemok) {
760ac839 322 PerlIO_puts(PerlIO_stderr(),"Out of memory!\n");
79072805 323 my_exit(1);
ee0007ab 324 }
45d8adaa 325#else
8d063cd8 326 return (NULL);
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327#endif
328 }
329
55497cff 330#ifdef PERL_CORE
760ac839 331 DEBUG_m(PerlIO_printf(Perl_debug_log, "0x%lx: (%05d) malloc %ld bytes\n",
a0d0e21e 332 (unsigned long)(p+1),an++,(long)size));
55497cff 333#endif /* PERL_CORE */
45d8adaa 334
8d063cd8 335 /* remove from linked list */
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336#ifdef RCHECK
337 if (*((int*)p) & (sizeof(union overhead) - 1))
760ac839 338 PerlIO_printf(PerlIO_stderr(), "Corrupt malloc ptr 0x%lx at 0x%lx\n",
a0d0e21e 339 (unsigned long)*((int*)p),(unsigned long)p);
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340#endif
341 nextf[bucket] = p->ov_next;
cf5c4ad8 342 OV_MAGIC(p, bucket) = MAGIC;
343#ifndef PACK_MALLOC
344 OV_INDEX(p) = bucket;
345#endif
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346#ifdef RCHECK
347 /*
348 * Record allocated size of block and
349 * bound space with magic numbers.
350 */
c2a5c2d2 351 nbytes = (size + M_OVERHEAD + 3) &~ 3;
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352 if (nbytes <= 0x10000)
353 p->ov_size = nbytes - 1;
354 p->ov_rmagic = RMAGIC;
355 *((u_int *)((caddr_t)p + nbytes - RSLOP)) = RMAGIC;
356#endif
cf5c4ad8 357 return ((Malloc_t)(p + CHUNK_SHIFT));
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358}
359
360/*
361 * Allocate more memory to the indicated bucket.
362 */
a0d0e21e 363static void
8d063cd8 364morecore(bucket)
a687059c 365 register int bucket;
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366{
367 register union overhead *op;
368 register int rnu; /* 2^rnu bytes will be requested */
369 register int nblks; /* become nblks blocks of the desired size */
bbce6d69 370 register MEM_SIZE siz, needed;
cf5c4ad8 371 int slack = 0;
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372
373 if (nextf[bucket])
374 return;
55497cff 375 if (bucket == (sizeof(MEM_SIZE)*8 - 3)) {
376 croak("Allocation too large");
377 }
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378 /*
379 * Insure memory is allocated
380 * on a page boundary. Should
381 * make getpageize call?
382 */
ee0007ab 383#ifndef atarist /* on the atari we dont have to worry about this */
8d063cd8 384 op = (union overhead *)sbrk(0);
cf5c4ad8 385# ifndef I286
386# ifdef PACK_MALLOC
ff68c719 387 if ((u_int)op & 0x7ff)
388 (void)sbrk(slack = 2048 - ((u_int)op & 0x7ff));
cf5c4ad8 389# else
ff68c719 390 if ((u_int)op & 0x3ff)
391 (void)sbrk(slack = 1024 - ((u_int)op & 0x3ff));
cf5c4ad8 392# endif
5f05dabc 393# if defined(DEBUGGING_MSTATS)
cf5c4ad8 394 sbrk_slack += slack;
395# endif
396# else
a687059c 397 /* The sbrk(0) call on the I286 always returns the next segment */
cf5c4ad8 398# endif
ee0007ab 399#endif /* atarist */
a687059c 400
ee0007ab 401#if !(defined(I286) || defined(atarist))
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402 /* take 2k unless the block is bigger than that */
403 rnu = (bucket <= 8) ? 11 : bucket + 3;
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404#else
405 /* take 16k unless the block is bigger than that
ee0007ab 406 (80286s like large segments!), probably good on the atari too */
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407 rnu = (bucket <= 11) ? 14 : bucket + 3;
408#endif
8d063cd8 409 nblks = 1 << (rnu - (bucket + 3)); /* how many blocks to get */
bbce6d69 410 needed = (MEM_SIZE)1 << rnu;
55497cff 411#ifdef TWO_POT_OPTIMIZE
bbce6d69 412 needed += (bucket >= (FIRST_BIG_TWO_POT - 3) ? PERL_PAGESIZE : 0);
55497cff 413#endif
bbce6d69 414 op = (union overhead *)sbrk(needed);
8d063cd8 415 /* no more room! */
ff68c719 416 if (op == (union overhead *)-1) {
417 op = (union overhead *)emergency_sbrk(needed);
418 if (op == (union overhead *)-1)
8d063cd8 419 return;
ff68c719 420 }
5f05dabc 421#ifdef DEBUGGING_MSTATS
422 goodsbrk += needed;
423#endif
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424 /*
425 * Round up to minimum allocation size boundary
426 * and deduct from block count to reflect.
427 */
a687059c 428#ifndef I286
cf5c4ad8 429# ifdef PACK_MALLOC
ff68c719 430 if ((u_int)op & 0x7ff)
cf5c4ad8 431 croak("panic: Off-page sbrk");
432# endif
ff68c719 433 if ((u_int)op & 7) {
ee0007ab 434 op = (union overhead *)(((MEM_SIZE)op + 8) &~ 7);
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435 nblks--;
436 }
a687059c
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437#else
438 /* Again, this should always be ok on an 80286 */
439#endif
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440 /*
441 * Add new memory allocated to that on
442 * free list for this hash bucket.
443 */
8d063cd8 444 siz = 1 << (bucket + 3);
cf5c4ad8 445#ifdef PACK_MALLOC
446 *(u_char*)op = bucket; /* Fill index. */
447 if (bucket <= MAX_PACKED - 3) {
448 op = (union overhead *) ((char*)op + blk_shift[bucket]);
449 nblks = n_blks[bucket];
450# ifdef DEBUGGING_MSTATS
451 start_slack += blk_shift[bucket];
452# endif
453 } else if (bucket <= 11 - 1 - 3) {
454 op = (union overhead *) ((char*)op + blk_shift[bucket]);
455 /* nblks = n_blks[bucket]; */
456 siz -= sizeof(union overhead);
457 } else op++; /* One chunk per block. */
458#endif /* !PACK_MALLOC */
459 nextf[bucket] = op;
5f05dabc 460#ifdef DEBUGGING_MSTATS
461 nmalloc[bucket] += nblks;
462#endif
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463 while (--nblks > 0) {
464 op->ov_next = (union overhead *)((caddr_t)op + siz);
465 op = (union overhead *)((caddr_t)op + siz);
466 }
8595d6f1 467 /* Not all sbrks return zeroed memory.*/
cf5c4ad8 468 op->ov_next = (union overhead *)NULL;
cf5c4ad8 469#ifdef PACK_MALLOC
470 if (bucket == 7 - 3) { /* Special case, explanation is above. */
471 union overhead *n_op = nextf[7 - 3]->ov_next;
472 nextf[7 - 3] = (union overhead *)((caddr_t)nextf[7 - 3]
473 - sizeof(union overhead));
474 nextf[7 - 3]->ov_next = n_op;
475 }
476#endif /* !PACK_MALLOC */
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477}
478
94b6baf5 479Free_t
352d5a3a 480free(mp)
2304df62 481 Malloc_t mp;
8d063cd8 482{
ee0007ab 483 register MEM_SIZE size;
8d063cd8 484 register union overhead *op;
352d5a3a 485 char *cp = (char*)mp;
cf5c4ad8 486#ifdef PACK_MALLOC
487 u_char bucket;
488#endif
8d063cd8 489
55497cff 490#ifdef PERL_CORE
760ac839 491 DEBUG_m(PerlIO_printf(Perl_debug_log, "0x%lx: (%05d) free\n",(unsigned long)cp,an++));
55497cff 492#endif /* PERL_CORE */
45d8adaa 493
cf5c4ad8 494 if (cp == NULL)
495 return;
496 op = (union overhead *)((caddr_t)cp
497 - sizeof (union overhead) * CHUNK_SHIFT);
498#ifdef PACK_MALLOC
499 bucket = OV_INDEX(op);
500#endif
cf5c4ad8 501 if (OV_MAGIC(op, bucket) != MAGIC) {
502 static bad_free_warn = -1;
503 if (bad_free_warn == -1) {
504 char *pbf = getenv("PERL_BADFREE");
505 bad_free_warn = (pbf) ? atoi(pbf) : 1;
506 }
507 if (!bad_free_warn)
508 return;
8990e307 509#ifdef RCHECK
a687059c 510 warn("%s free() ignored",
8990e307
LW
511 op->ov_rmagic == RMAGIC - 1 ? "Duplicate" : "Bad");
512#else
513 warn("Bad free() ignored");
514#endif
8d063cd8 515 return; /* sanity */
378cc40b 516 }
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517#ifdef RCHECK
518 ASSERT(op->ov_rmagic == RMAGIC);
c2a5c2d2 519 if (OV_INDEX(op) <= MAX_SHORT_BUCKET)
8d063cd8 520 ASSERT(*(u_int *)((caddr_t)op + op->ov_size + 1 - RSLOP) == RMAGIC);
8990e307 521 op->ov_rmagic = RMAGIC - 1;
8d063cd8 522#endif
cf5c4ad8 523 ASSERT(OV_INDEX(op) < NBUCKETS);
524 size = OV_INDEX(op);
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LW
525 op->ov_next = nextf[size];
526 nextf[size] = op;
8d063cd8
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527}
528
529/*
530 * When a program attempts "storage compaction" as mentioned in the
531 * old malloc man page, it realloc's an already freed block. Usually
532 * this is the last block it freed; occasionally it might be farther
533 * back. We have to search all the free lists for the block in order
534 * to determine its bucket: 1st we make one pass thru the lists
535 * checking only the first block in each; if that fails we search
378cc40b 536 * ``reall_srchlen'' blocks in each list for a match (the variable
8d063cd8
LW
537 * is extern so the caller can modify it). If that fails we just copy
538 * however many bytes was given to realloc() and hope it's not huge.
539 */
378cc40b 540int reall_srchlen = 4; /* 4 should be plenty, -1 =>'s whole list */
8d063cd8 541
2304df62 542Malloc_t
352d5a3a 543realloc(mp, nbytes)
2304df62 544 Malloc_t mp;
ee0007ab 545 MEM_SIZE nbytes;
8d063cd8 546{
ee0007ab 547 register MEM_SIZE onb;
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548 union overhead *op;
549 char *res;
550 register int i;
551 int was_alloced = 0;
352d5a3a 552 char *cp = (char*)mp;
8d063cd8 553
45d8adaa 554#ifdef DEBUGGING
ee0007ab 555 MEM_SIZE size = nbytes;
45d8adaa
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556#endif
557
043bf814 558#ifdef PERL_CORE
55497cff 559#ifdef HAS_64K_LIMIT
45d8adaa 560 if (nbytes > 0xffff) {
043bf814
RB
561 PerlIO_printf(PerlIO_stderr(),
562 "Reallocation too large: %lx\n", size);
79072805 563 my_exit(1);
45d8adaa 564 }
55497cff 565#endif /* HAS_64K_LIMIT */
45d8adaa 566 if (!cp)
ee0007ab 567 return malloc(nbytes);
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LW
568#ifdef DEBUGGING
569 if ((long)nbytes < 0)
463ee0b2 570 croak("panic: realloc");
45d8adaa 571#endif
55497cff 572#endif /* PERL_CORE */
45d8adaa 573
cf5c4ad8 574 op = (union overhead *)((caddr_t)cp
575 - sizeof (union overhead) * CHUNK_SHIFT);
576 i = OV_INDEX(op);
577 if (OV_MAGIC(op, i) == MAGIC) {
55497cff 578 was_alloced = 1;
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579 } else {
580 /*
581 * Already free, doing "compaction".
582 *
583 * Search for the old block of memory on the
584 * free list. First, check the most common
585 * case (last element free'd), then (this failing)
378cc40b 586 * the last ``reall_srchlen'' items free'd.
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587 * If all lookups fail, then assume the size of
588 * the memory block being realloc'd is the
589 * smallest possible.
590 */
591 if ((i = findbucket(op, 1)) < 0 &&
378cc40b 592 (i = findbucket(op, reall_srchlen)) < 0)
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593 i = 0;
594 }
cf5c4ad8 595 onb = (1L << (i + 3)) -
596#ifdef PACK_MALLOC
597 (i <= (MAX_PACKED - 3) ? 0 : M_OVERHEAD)
598#else
599 M_OVERHEAD
600#endif
55497cff 601#ifdef TWO_POT_OPTIMIZE
602 + (i >= (FIRST_BIG_TWO_POT - 3) ? PERL_PAGESIZE : 0)
603#endif
cf5c4ad8 604 ;
55497cff 605 /*
606 * avoid the copy if same size block.
607 * We are not agressive with boundary cases. Note that it is
608 * possible for small number of cases give false negative if
609 * both new size and old one are in the bucket for
610 * FIRST_BIG_TWO_POT, but the new one is near the lower end.
611 */
8d063cd8 612 if (was_alloced &&
55497cff 613 nbytes <= onb && (nbytes > ( (onb >> 1) - M_OVERHEAD )
614#ifdef TWO_POT_OPTIMIZE
615 || (i == (FIRST_BIG_TWO_POT - 3)
616 && nbytes >= LAST_SMALL_BOUND )
617#endif
618 )) {
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619#ifdef RCHECK
620 /*
621 * Record new allocated size of block and
622 * bound space with magic numbers.
623 */
c2a5c2d2 624 if (OV_INDEX(op) <= MAX_SHORT_BUCKET) {
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625 /*
626 * Convert amount of memory requested into
627 * closest block size stored in hash buckets
628 * which satisfies request. Account for
629 * space used per block for accounting.
630 */
cf5c4ad8 631 nbytes += M_OVERHEAD;
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632 nbytes = (nbytes + 3) &~ 3;
633 op->ov_size = nbytes - 1;
634 *((u_int *)((caddr_t)op + nbytes - RSLOP)) = RMAGIC;
635 }
636#endif
45d8adaa 637 res = cp;
a687059c 638 }
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639 else {
640 if ((res = (char*)malloc(nbytes)) == NULL)
641 return (NULL);
642 if (cp != res) /* common optimization */
ee0007ab 643 Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char);
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644 if (was_alloced)
645 free(cp);
646 }
647
55497cff 648#ifdef PERL_CORE
45d8adaa 649#ifdef DEBUGGING
a0d0e21e 650 if (debug & 128) {
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651 PerlIO_printf(PerlIO_stderr(), "0x%lx: (%05d) rfree\n",(unsigned long)res,an++);
652 PerlIO_printf(PerlIO_stderr(), "0x%lx: (%05d) realloc %ld bytes\n",
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653 (unsigned long)res,an++,(long)size);
654 }
45d8adaa 655#endif
55497cff 656#endif /* PERL_CORE */
2304df62 657 return ((Malloc_t)res);
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658}
659
660/*
661 * Search ``srchlen'' elements of each free list for a block whose
662 * header starts at ``freep''. If srchlen is -1 search the whole list.
663 * Return bucket number, or -1 if not found.
664 */
ee0007ab 665static int
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666findbucket(freep, srchlen)
667 union overhead *freep;
668 int srchlen;
669{
670 register union overhead *p;
671 register int i, j;
672
673 for (i = 0; i < NBUCKETS; i++) {
674 j = 0;
675 for (p = nextf[i]; p && j != srchlen; p = p->ov_next) {
676 if (p == freep)
677 return (i);
678 j++;
679 }
680 }
681 return (-1);
682}
683
cf5c4ad8 684Malloc_t
685calloc(elements, size)
686 register MEM_SIZE elements;
687 register MEM_SIZE size;
688{
689 long sz = elements * size;
690 Malloc_t p = malloc(sz);
691
692 if (p) {
693 memset((void*)p, 0, sz);
694 }
695 return p;
696}
697
c07a80fd 698#ifdef DEBUGGING_MSTATS
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699/*
700 * mstats - print out statistics about malloc
701 *
702 * Prints two lines of numbers, one showing the length of the free list
703 * for each size category, the second showing the number of mallocs -
704 * frees for each size category.
705 */
ee0007ab 706void
c07a80fd 707dump_mstats(s)
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708 char *s;
709{
710 register int i, j;
711 register union overhead *p;
5f05dabc 712 int topbucket=0, totfree=0, total=0;
c07a80fd 713 u_int nfree[NBUCKETS];
8d063cd8 714
c07a80fd 715 for (i=0; i < NBUCKETS; i++) {
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716 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
717 ;
c07a80fd 718 nfree[i] = j;
719 totfree += nfree[i] * (1 << (i + 3));
5f05dabc 720 total += nmalloc[i] * (1 << (i + 3));
721 if (nmalloc[i])
c07a80fd 722 topbucket = i;
723 }
724 if (s)
760ac839 725 PerlIO_printf(PerlIO_stderr(), "Memory allocation statistics %s (buckets 8..%d)\n",
c07a80fd 726 s, (1 << (topbucket + 3)) );
5f05dabc 727 PerlIO_printf(PerlIO_stderr(), "%8d free:", totfree);
c07a80fd 728 for (i=0; i <= topbucket; i++) {
5f05dabc 729 PerlIO_printf(PerlIO_stderr(), (i<5 || i==7)?" %5d": (i<9)?" %3d":" %d", nfree[i]);
8d063cd8 730 }
5f05dabc 731 PerlIO_printf(PerlIO_stderr(), "\n%8d used:", total - totfree);
c07a80fd 732 for (i=0; i <= topbucket; i++) {
5f05dabc 733 PerlIO_printf(PerlIO_stderr(), (i<5 || i==7)?" %5d": (i<9)?" %3d":" %d", nmalloc[i] - nfree[i]);
c07a80fd 734 }
5f05dabc 735 PerlIO_printf(PerlIO_stderr(), "\nTotal sbrk(): %8d. Odd ends: sbrk(): %7d, malloc(): %7d bytes.\n",
736 goodsbrk + sbrk_slack, sbrk_slack, start_slack);
c07a80fd 737}
738#else
739void
740dump_mstats(s)
741 char *s;
742{
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743}
744#endif
a687059c 745#endif /* lint */
cf5c4ad8 746
747
748#ifdef USE_PERL_SBRK
749
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750# ifdef NeXT
751# define PERL_SBRK_VIA_MALLOC
752# endif
753
754# ifdef PERL_SBRK_VIA_MALLOC
72e5b9db 755# if defined(HIDEMYMALLOC) || defined(EMBEDMYMALLOC)
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756# undef malloc
757# else
72e5b9db 758# include "Error: -DPERL_SBRK_VIA_MALLOC needs -D(HIDE|EMBED)MYMALLOC"
760ac839 759# endif
cf5c4ad8 760
761/* it may seem schizophrenic to use perl's malloc and let it call system */
762/* malloc, the reason for that is only the 3.2 version of the OS that had */
763/* frequent core dumps within nxzonefreenolock. This sbrk routine put an */
764/* end to the cores */
765
760ac839 766# define SYSTEM_ALLOC(a) malloc(a)
cf5c4ad8 767
760ac839 768# endif /* PERL_SBRK_VIA_MALLOC */
cf5c4ad8 769
770static IV Perl_sbrk_oldchunk;
771static long Perl_sbrk_oldsize;
772
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773# define PERLSBRK_32_K (1<<15)
774# define PERLSBRK_64_K (1<<16)
cf5c4ad8 775
776char *
777Perl_sbrk(size)
778int size;
779{
780 IV got;
781 int small, reqsize;
782
783 if (!size) return 0;
55497cff 784#ifdef PERL_CORE
cf5c4ad8 785 reqsize = size; /* just for the DEBUG_m statement */
786#endif
787 if (size <= Perl_sbrk_oldsize) {
788 got = Perl_sbrk_oldchunk;
789 Perl_sbrk_oldchunk += size;
790 Perl_sbrk_oldsize -= size;
791 } else {
792 if (size >= PERLSBRK_32_K) {
793 small = 0;
794 } else {
55497cff 795#ifndef PERL_CORE
cf5c4ad8 796 reqsize = size;
797#endif
798 size = PERLSBRK_64_K;
799 small = 1;
800 }
801 got = (IV)SYSTEM_ALLOC(size);
802 if (small) {
803 /* Chunk is small, register the rest for future allocs. */
804 Perl_sbrk_oldchunk = got + reqsize;
805 Perl_sbrk_oldsize = size - reqsize;
806 }
807 }
808
55497cff 809#ifdef PERL_CORE
760ac839 810 DEBUG_m(PerlIO_printf(PerlIO_stderr(), "sbrk malloc size %ld (reqsize %ld), left size %ld, give addr 0x%lx\n",
cf5c4ad8 811 size, reqsize, Perl_sbrk_oldsize, got));
812#endif
813
814 return (void *)got;
815}
816
817#endif /* ! defined USE_PERL_SBRK */