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avoid using context pointer in MUTEX_INIT() et al; remove the
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a0d0e21e 1/* malloc.c
8d063cd8 2 *
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3 */
4
87c6202a 5/*
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6 Here are some notes on configuring Perl's malloc. (For non-perl
7 usage see below.)
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8
9 There are two macros which serve as bulk disablers of advanced
10 features of this malloc: NO_FANCY_MALLOC, PLAIN_MALLOC (undef by
11 default). Look in the list of default values below to understand
12 their exact effect. Defining NO_FANCY_MALLOC returns malloc.c to the
13 state of the malloc in Perl 5.004. Additionally defining PLAIN_MALLOC
14 returns it to the state as of Perl 5.000.
15
16 Note that some of the settings below may be ignored in the code based
17 on values of other macros. The PERL_CORE symbol is only defined when
18 perl itself is being compiled (so malloc can make some assumptions
19 about perl's facilities being available to it).
20
21 Each config option has a short description, followed by its name,
22 default value, and a comment about the default (if applicable). Some
23 options take a precise value, while the others are just boolean.
24 The boolean ones are listed first.
25
26 # Enable code for an emergency memory pool in $^M. See perlvar.pod
27 # for a description of $^M.
28 PERL_EMERGENCY_SBRK (!PLAIN_MALLOC && PERL_CORE)
29
30 # Enable code for printing memory statistics.
31 DEBUGGING_MSTATS (!PLAIN_MALLOC && PERL_CORE)
32
33 # Move allocation info for small buckets into separate areas.
34 # Memory optimization (especially for small allocations, of the
35 # less than 64 bytes). Since perl usually makes a large number
36 # of small allocations, this is usually a win.
37 PACK_MALLOC (!PLAIN_MALLOC && !RCHECK)
38
39 # Add one page to big powers of two when calculating bucket size.
40 # This is targeted at big allocations, as are common in image
41 # processing.
42 TWO_POT_OPTIMIZE !PLAIN_MALLOC
43
44 # Use intermediate bucket sizes between powers-of-two. This is
45 # generally a memory optimization, and a (small) speed pessimization.
46 BUCKETS_ROOT2 !NO_FANCY_MALLOC
47
48 # Do not check small deallocations for bad free(). Memory
49 # and speed optimization, error reporting pessimization.
50 IGNORE_SMALL_BAD_FREE (!NO_FANCY_MALLOC && !RCHECK)
51
52 # Use table lookup to decide in which bucket a given allocation will go.
53 SMALL_BUCKET_VIA_TABLE !NO_FANCY_MALLOC
54
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55 # Use a perl-defined sbrk() instead of the (presumably broken or
56 # missing) system-supplied sbrk().
57 USE_PERL_SBRK undef
58
59 # Use system malloc() (or calloc() etc.) to emulate sbrk(). Normally
60 # only used with broken sbrk()s.
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61 PERL_SBRK_VIA_MALLOC undef
62
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63 # Which allocator to use if PERL_SBRK_VIA_MALLOC
64 SYSTEM_ALLOC(a) malloc(a)
65
9ee81ef6 66 # Minimal alignment (in bytes, should be a power of 2) of SYSTEM_ALLOC
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67 SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES
68
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69 # Disable memory overwrite checking with DEBUGGING. Memory and speed
70 # optimization, error reporting pessimization.
71 NO_RCHECK undef
72
73 # Enable memory overwrite checking with DEBUGGING. Memory and speed
74 # pessimization, error reporting optimization
75 RCHECK (DEBUGGING && !NO_RCHECK)
76
77 # Failed allocations bigger than this size croak (if
78 # PERL_EMERGENCY_SBRK is enabled) without touching $^M. See
79 # perlvar.pod for a description of $^M.
80 BIG_SIZE (1<<16) # 64K
81
82 # Starting from this power of two, add an extra page to the
83 # size of the bucket. This enables optimized allocations of sizes
84 # close to powers of 2. Note that the value is indexed at 0.
85 FIRST_BIG_POW2 15 # 32K, 16K is used too often
86
87 # Estimate of minimal memory footprint. malloc uses this value to
88 # request the most reasonable largest blocks of memory from the system.
89 FIRST_SBRK (48*1024)
90
91 # Round up sbrk()s to multiples of this.
92 MIN_SBRK 2048
93
94 # Round up sbrk()s to multiples of this percent of footprint.
95 MIN_SBRK_FRAC 3
96
97 # Add this much memory to big powers of two to get the bucket size.
98 PERL_PAGESIZE 4096
99
100 # This many sbrk() discontinuities should be tolerated even
101 # from the start without deciding that sbrk() is usually
102 # discontinuous.
103 SBRK_ALLOW_FAILURES 3
104
105 # This many continuous sbrk()s compensate for one discontinuous one.
106 SBRK_FAILURE_PRICE 50
107
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108 # Some configurations may ask for 12-byte-or-so allocations which
109 # require 8-byte alignment (?!). In such situation one needs to
110 # define this to disable 12-byte bucket (will increase memory footprint)
111 STRICT_ALIGNMENT undef
112
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113 This implementation assumes that calling PerlIO_printf() does not
114 result in any memory allocation calls (used during a panic).
115
116 */
117
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118/*
119 If used outside of Perl environment, it may be useful to redefine
120 the following macros (listed below with defaults):
121
122 # Type of address returned by allocation functions
123 Malloc_t void *
124
125 # Type of size argument for allocation functions
126 MEM_SIZE unsigned long
127
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128 # size of void*
129 PTRSIZE 4
130
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131 # Maximal value in LONG
132 LONG_MAX 0x7FFFFFFF
133
134 # Unsigned integer type big enough to keep a pointer
135 UV unsigned long
136
137 # Type of pointer with 1-byte granularity
138 caddr_t char *
139
140 # Type returned by free()
141 Free_t void
142
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143 # Very fatal condition reporting function (cannot call any )
144 fatalcroak(arg) write(2,arg,strlen(arg)) + exit(2)
145
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146 # Fatal error reporting function
147 croak(format, arg) warn(idem) + exit(1)
148
149 # Error reporting function
150 warn(format, arg) fprintf(stderr, idem)
151
152 # Locking/unlocking for MT operation
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153 MALLOC_LOCK MUTEX_LOCK(&PL_malloc_mutex)
154 MALLOC_UNLOCK MUTEX_UNLOCK(&PL_malloc_mutex)
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155
156 # Locking/unlocking mutex for MT operation
157 MUTEX_LOCK(l) void
158 MUTEX_UNLOCK(l) void
159 */
160
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161#ifndef NO_FANCY_MALLOC
162# ifndef SMALL_BUCKET_VIA_TABLE
163# define SMALL_BUCKET_VIA_TABLE
164# endif
165# ifndef BUCKETS_ROOT2
166# define BUCKETS_ROOT2
167# endif
168# ifndef IGNORE_SMALL_BAD_FREE
169# define IGNORE_SMALL_BAD_FREE
170# endif
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171#endif
172
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173#ifndef PLAIN_MALLOC /* Bulk enable features */
174# ifndef PACK_MALLOC
175# define PACK_MALLOC
176# endif
177# ifndef TWO_POT_OPTIMIZE
178# define TWO_POT_OPTIMIZE
179# endif
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180# if defined(PERL_CORE) && !defined(PERL_EMERGENCY_SBRK)
181# define PERL_EMERGENCY_SBRK
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182# endif
183# if defined(PERL_CORE) && !defined(DEBUGGING_MSTATS)
184# define DEBUGGING_MSTATS
185# endif
186#endif
187
188#define MIN_BUC_POW2 (sizeof(void*) > 4 ? 3 : 2) /* Allow for 4-byte arena. */
189#define MIN_BUCKET (MIN_BUC_POW2 * BUCKETS_PER_POW2)
190
61ae2fbf 191#if !(defined(I286) || defined(atarist) || defined(__MINT__))
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192 /* take 2k unless the block is bigger than that */
193# define LOG_OF_MIN_ARENA 11
194#else
195 /* take 16k unless the block is bigger than that
196 (80286s like large segments!), probably good on the atari too */
197# define LOG_OF_MIN_ARENA 14
198#endif
199
8d063cd8 200#ifndef lint
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201# if defined(DEBUGGING) && !defined(NO_RCHECK)
202# define RCHECK
203# endif
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204# if defined(RCHECK) && defined(IGNORE_SMALL_BAD_FREE)
205# undef IGNORE_SMALL_BAD_FREE
206# endif
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207/*
208 * malloc.c (Caltech) 2/21/82
209 * Chris Kingsley, kingsley@cit-20.
210 *
211 * This is a very fast storage allocator. It allocates blocks of a small
212 * number of different sizes, and keeps free lists of each size. Blocks that
213 * don't exactly fit are passed up to the next larger size. In this
214 * implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long.
cf5c4ad8 215 * If PACK_MALLOC is defined, small blocks are 2^n bytes long.
8d063cd8 216 * This is designed for use in a program that uses vast quantities of memory,
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217 * but bombs when it runs out.
218 *
4eb8286e 219 * Modifications Copyright Ilya Zakharevich 1996-99.
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220 *
221 * Still very quick, but much more thrifty. (Std config is 10% slower
222 * than it was, and takes 67% of old heap size for typical usage.)
223 *
224 * Allocations of small blocks are now table-driven to many different
225 * buckets. Sizes of really big buckets are increased to accomodata
226 * common size=power-of-2 blocks. Running-out-of-memory is made into
227 * an exception. Deeply configurable and thread-safe.
228 *
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229 */
230
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231#ifdef PERL_CORE
232# include "EXTERN.h"
4ad56ec9 233# define PERL_IN_MALLOC_C
d720c441 234# include "perl.h"
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235# if defined(PERL_IMPLICIT_CONTEXT)
236# define croak Perl_croak_nocontext
237# define warn Perl_warn_nocontext
238# endif
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239#else
240# ifdef PERL_FOR_X2P
241# include "../EXTERN.h"
242# include "../perl.h"
243# else
244# include <stdlib.h>
245# include <stdio.h>
246# include <memory.h>
247# define _(arg) arg
248# ifndef Malloc_t
249# define Malloc_t void *
250# endif
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251# ifndef PTRSIZE
252# define PTRSIZE 4
253# endif
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254# ifndef MEM_SIZE
255# define MEM_SIZE unsigned long
256# endif
257# ifndef LONG_MAX
258# define LONG_MAX 0x7FFFFFFF
259# endif
260# ifndef UV
261# define UV unsigned long
262# endif
263# ifndef caddr_t
264# define caddr_t char *
265# endif
266# ifndef Free_t
267# define Free_t void
268# endif
269# define Copy(s,d,n,t) (void)memcpy((char*)(d),(char*)(s), (n) * sizeof(t))
270# define PerlEnv_getenv getenv
271# define PerlIO_printf fprintf
272# define PerlIO_stderr() stderr
273# endif
e8bc2b5c 274# ifndef croak /* make depend */
741df71a 275# define croak(mess, arg) (warn((mess), (arg)), exit(1))
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276# endif
277# ifndef warn
741df71a 278# define warn(mess, arg) fprintf(stderr, (mess), (arg))
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279# endif
280# ifdef DEBUG_m
281# undef DEBUG_m
282# endif
283# define DEBUG_m(a)
284# ifdef DEBUGGING
285# undef DEBUGGING
286# endif
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287# ifndef pTHX
288# define pTHX void
289# define pTHX_
290# define dTHX extern int Perl___notused
291# define WITH_THX(s) s
292# endif
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293# ifndef PERL_GET_INTERP
294# define PERL_GET_INTERP PL_curinterp
295# endif
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296# ifndef Perl_malloc
297# define Perl_malloc malloc
298# endif
299# ifndef Perl_mfree
300# define Perl_mfree free
301# endif
302# ifndef Perl_realloc
303# define Perl_realloc realloc
304# endif
305# ifndef Perl_calloc
306# define Perl_calloc calloc
307# endif
308# ifndef Perl_strdup
309# define Perl_strdup strdup
310# endif
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311#endif
312
313#ifndef MUTEX_LOCK
314# define MUTEX_LOCK(l)
315#endif
316
317#ifndef MUTEX_UNLOCK
318# define MUTEX_UNLOCK(l)
319#endif
320
741df71a 321#ifndef MALLOC_LOCK
efc57feb 322# define MALLOC_LOCK MUTEX_LOCK(&PL_malloc_mutex)
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323#endif
324
325#ifndef MALLOC_UNLOCK
efc57feb 326# define MALLOC_UNLOCK MUTEX_UNLOCK(&PL_malloc_mutex)
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327#endif
328
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329# ifndef fatalcroak /* make depend */
330# define fatalcroak(mess) (write(2, (mess), strlen(mess)), exit(2))
331# endif
332
760ac839 333#ifdef DEBUGGING
e8bc2b5c 334# undef DEBUG_m
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335# define DEBUG_m(a) \
336 STMT_START { \
337 if (PERL_GET_INTERP) { dTHX; if (PL_debug & 128) { a; } } \
338 } STMT_END
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339#endif
340
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341#ifdef PERL_IMPLICIT_CONTEXT
342# define PERL_IS_ALIVE aTHX
343#else
344# define PERL_IS_ALIVE TRUE
345#endif
346
347
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348/*
349 * Layout of memory:
350 * ~~~~~~~~~~~~~~~~
351 * The memory is broken into "blocks" which occupy multiples of 2K (and
352 * generally speaking, have size "close" to a power of 2). The addresses
353 * of such *unused* blocks are kept in nextf[i] with big enough i. (nextf
354 * is an array of linked lists.) (Addresses of used blocks are not known.)
355 *
4ad56ec9 356 * Moreover, since the algorithm may try to "bite" smaller blocks out
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357 * of unused bigger ones, there are also regions of "irregular" size,
358 * managed separately, by a linked list chunk_chain.
359 *
360 * The third type of storage is the sbrk()ed-but-not-yet-used space, its
361 * end and size are kept in last_sbrk_top and sbrked_remains.
362 *
363 * Growing blocks "in place":
364 * ~~~~~~~~~~~~~~~~~~~~~~~~~
365 * The address of the block with the greatest address is kept in last_op
366 * (if not known, last_op is 0). If it is known that the memory above
367 * last_op is not continuous, or contains a chunk from chunk_chain,
368 * last_op is set to 0.
369 *
370 * The chunk with address last_op may be grown by expanding into
371 * sbrk()ed-but-not-yet-used space, or trying to sbrk() more continuous
372 * memory.
373 *
374 * Management of last_op:
375 * ~~~~~~~~~~~~~~~~~~~~~
376 *
377 * free() never changes the boundaries of blocks, so is not relevant.
378 *
379 * The only way realloc() may change the boundaries of blocks is if it
380 * grows a block "in place". However, in the case of success such a
381 * chunk is automatically last_op, and it remains last_op. In the case
382 * of failure getpages_adjacent() clears last_op.
383 *
384 * malloc() may change blocks by calling morecore() only.
385 *
386 * morecore() may create new blocks by:
387 * a) biting pieces from chunk_chain (cannot create one above last_op);
388 * b) biting a piece from an unused block (if block was last_op, this
389 * may create a chunk from chain above last_op, thus last_op is
390 * invalidated in such a case).
391 * c) biting of sbrk()ed-but-not-yet-used space. This creates
392 * a block which is last_op.
393 * d) Allocating new pages by calling getpages();
394 *
395 * getpages() creates a new block. It marks last_op at the bottom of
396 * the chunk of memory it returns.
397 *
398 * Active pages footprint:
399 * ~~~~~~~~~~~~~~~~~~~~~~
400 * Note that we do not need to traverse the lists in nextf[i], just take
401 * the first element of this list. However, we *need* to traverse the
402 * list in chunk_chain, but most the time it should be a very short one,
403 * so we do not step on a lot of pages we are not going to use.
404 *
405 * Flaws:
406 * ~~~~~
407 * get_from_bigger_buckets(): forget to increment price => Quite
408 * aggressive.
409 */
410
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411/* I don't much care whether these are defined in sys/types.h--LAW */
412
413#define u_char unsigned char
414#define u_int unsigned int
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415/*
416 * I removed the definition of u_bigint which appeared to be u_bigint = UV
417 * u_bigint was only used in TWOK_MASKED and TWOK_SHIFT
418 * where I have used PTR2UV. RMB
419 */
135863df 420#define u_short unsigned short
8d063cd8 421
cf5c4ad8 422/* 286 and atarist like big chunks, which gives too much overhead. */
61ae2fbf 423#if (defined(RCHECK) || defined(I286) || defined(atarist) || defined(__MINT__)) && defined(PACK_MALLOC)
e8bc2b5c 424# undef PACK_MALLOC
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425#endif
426
8d063cd8 427/*
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428 * The description below is applicable if PACK_MALLOC is not defined.
429 *
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430 * The overhead on a block is at least 4 bytes. When free, this space
431 * contains a pointer to the next free block, and the bottom two bits must
432 * be zero. When in use, the first byte is set to MAGIC, and the second
433 * byte is the size index. The remaining bytes are for alignment.
434 * If range checking is enabled and the size of the block fits
435 * in two bytes, then the top two bytes hold the size of the requested block
436 * plus the range checking words, and the header word MINUS ONE.
437 */
438union overhead {
439 union overhead *ov_next; /* when free */
85e6fe83 440#if MEM_ALIGNBYTES > 4
c623bd54 441 double strut; /* alignment problems */
a687059c 442#endif
8d063cd8 443 struct {
8d063cd8 444 u_char ovu_index; /* bucket # */
b72ff565 445 u_char ovu_magic; /* magic number */
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446#ifdef RCHECK
447 u_short ovu_size; /* actual block size */
448 u_int ovu_rmagic; /* range magic number */
449#endif
450 } ovu;
451#define ov_magic ovu.ovu_magic
452#define ov_index ovu.ovu_index
453#define ov_size ovu.ovu_size
454#define ov_rmagic ovu.ovu_rmagic
455};
456
457#define MAGIC 0xff /* magic # on accounting info */
458#define RMAGIC 0x55555555 /* magic # on range info */
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459#define RMAGIC_C 0x55 /* magic # on range info */
460
8d063cd8 461#ifdef RCHECK
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462# define RSLOP sizeof (u_int)
463# ifdef TWO_POT_OPTIMIZE
e8bc2b5c 464# define MAX_SHORT_BUCKET (12 * BUCKETS_PER_POW2)
c2a5c2d2 465# else
e8bc2b5c 466# define MAX_SHORT_BUCKET (13 * BUCKETS_PER_POW2)
c2a5c2d2 467# endif
8d063cd8 468#else
c2a5c2d2 469# define RSLOP 0
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470#endif
471
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472#if !defined(PACK_MALLOC) && defined(BUCKETS_ROOT2)
473# undef BUCKETS_ROOT2
474#endif
475
476#ifdef BUCKETS_ROOT2
477# define BUCKET_TABLE_SHIFT 2
478# define BUCKET_POW2_SHIFT 1
479# define BUCKETS_PER_POW2 2
480#else
481# define BUCKET_TABLE_SHIFT MIN_BUC_POW2
482# define BUCKET_POW2_SHIFT 0
483# define BUCKETS_PER_POW2 1
484#endif
485
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486#if !defined(MEM_ALIGNBYTES) || ((MEM_ALIGNBYTES > 4) && !defined(STRICT_ALIGNMENT))
487/* Figure out the alignment of void*. */
488struct aligner {
489 char c;
490 void *p;
491};
492# define ALIGN_SMALL ((int)((caddr_t)&(((struct aligner*)0)->p)))
493#else
494# define ALIGN_SMALL MEM_ALIGNBYTES
495#endif
496
497#define IF_ALIGN_8(yes,no) ((ALIGN_SMALL>4) ? (yes) : (no))
498
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499#ifdef BUCKETS_ROOT2
500# define MAX_BUCKET_BY_TABLE 13
501static u_short buck_size[MAX_BUCKET_BY_TABLE + 1] =
502 {
503 0, 0, 0, 0, 4, 4, 8, 12, 16, 24, 32, 48, 64, 80,
504 };
505# define BUCKET_SIZE(i) ((i) % 2 ? buck_size[i] : (1 << ((i) >> BUCKET_POW2_SHIFT)))
506# define BUCKET_SIZE_REAL(i) ((i) <= MAX_BUCKET_BY_TABLE \
507 ? buck_size[i] \
508 : ((1 << ((i) >> BUCKET_POW2_SHIFT)) \
509 - MEM_OVERHEAD(i) \
510 + POW2_OPTIMIZE_SURPLUS(i)))
511#else
512# define BUCKET_SIZE(i) (1 << ((i) >> BUCKET_POW2_SHIFT))
513# define BUCKET_SIZE_REAL(i) (BUCKET_SIZE(i) - MEM_OVERHEAD(i) + POW2_OPTIMIZE_SURPLUS(i))
514#endif
515
516
cf5c4ad8 517#ifdef PACK_MALLOC
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518/* In this case there are several possible layout of arenas depending
519 * on the size. Arenas are of sizes multiple to 2K, 2K-aligned, and
520 * have a size close to a power of 2.
521 *
522 * Arenas of the size >= 4K keep one chunk only. Arenas of size 2K
523 * may keep one chunk or multiple chunks. Here are the possible
524 * layouts of arenas:
525 *
526 * # One chunk only, chunksize 2^k + SOMETHING - ALIGN, k >= 11
527 *
528 * INDEX MAGIC1 UNUSED CHUNK1
529 *
530 * # Multichunk with sanity checking and chunksize 2^k-ALIGN, k>7
531 *
532 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 CHUNK2 CHUNK3 ...
533 *
534 * # Multichunk with sanity checking and size 2^k-ALIGN, k=7
535 *
536 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 UNUSED CHUNK2 CHUNK3 ...
537 *
538 * # Multichunk with sanity checking and size up to 80
539 *
540 * INDEX UNUSED MAGIC1 UNUSED MAGIC2 UNUSED ... CHUNK1 CHUNK2 CHUNK3 ...
541 *
542 * # No sanity check (usually up to 48=byte-long buckets)
543 * INDEX UNUSED CHUNK1 CHUNK2 ...
544 *
545 * Above INDEX and MAGIC are one-byte-long. Sizes of UNUSED are
546 * appropriate to keep algorithms simple and memory aligned. INDEX
547 * encodes the size of the chunk, while MAGICn encodes state (used,
548 * free or non-managed-by-us-so-it-indicates-a-bug) of CHUNKn. MAGIC
549 * is used for sanity checking purposes only. SOMETHING is 0 or 4K
550 * (to make size of big CHUNK accomodate allocations for powers of two
551 * better).
552 *
553 * [There is no need to alignment between chunks, since C rules ensure
554 * that structs which need 2^k alignment have sizeof which is
555 * divisible by 2^k. Thus as far as the last chunk is aligned at the
556 * end of the arena, and 2K-alignment does not contradict things,
557 * everything is going to be OK for sizes of chunks 2^n and 2^n +
558 * 2^k. Say, 80-bit buckets will be 16-bit aligned, and as far as we
559 * put allocations for requests in 65..80 range, all is fine.
560 *
561 * Note, however, that standard malloc() puts more strict
562 * requirements than the above C rules. Moreover, our algorithms of
563 * realloc() may break this idyll, but we suppose that realloc() does
564 * need not change alignment.]
565 *
566 * Is very important to make calculation of the offset of MAGICm as
567 * quick as possible, since it is done on each malloc()/free(). In
568 * fact it is so quick that it has quite little effect on the speed of
569 * doing malloc()/free(). [By default] We forego such calculations
570 * for small chunks, but only to save extra 3% of memory, not because
571 * of speed considerations.
572 *
573 * Here is the algorithm [which is the same for all the allocations
574 * schemes above], see OV_MAGIC(block,bucket). Let OFFSETm be the
575 * offset of the CHUNKm from the start of ARENA. Then offset of
576 * MAGICm is (OFFSET1 >> SHIFT) + ADDOFFSET. Here SHIFT and ADDOFFSET
577 * are numbers which depend on the size of the chunks only.
578 *
579 * Let as check some sanity conditions. Numbers OFFSETm>>SHIFT are
580 * different for all the chunks in the arena if 2^SHIFT is not greater
581 * than size of the chunks in the arena. MAGIC1 will not overwrite
582 * INDEX provided ADDOFFSET is >0 if OFFSET1 < 2^SHIFT. MAGIClast
583 * will not overwrite CHUNK1 if OFFSET1 > (OFFSETlast >> SHIFT) +
584 * ADDOFFSET.
585 *
586 * Make SHIFT the maximal possible (there is no point in making it
587 * smaller). Since OFFSETlast is 2K - CHUNKSIZE, above restrictions
588 * give restrictions on OFFSET1 and on ADDOFFSET.
589 *
590 * In particular, for chunks of size 2^k with k>=6 we can put
591 * ADDOFFSET to be from 0 to 2^k - 2^(11-k), and have
592 * OFFSET1==chunksize. For chunks of size 80 OFFSET1 of 2K%80=48 is
593 * large enough to have ADDOFFSET between 1 and 16 (similarly for 96,
594 * when ADDOFFSET should be 1). In particular, keeping MAGICs for
595 * these sizes gives no additional size penalty.
596 *
597 * However, for chunks of size 2^k with k<=5 this gives OFFSET1 >=
598 * ADDOFSET + 2^(11-k). Keeping ADDOFFSET 0 allows for 2^(11-k)-2^(11-2k)
599 * chunks per arena. This is smaller than 2^(11-k) - 1 which are
600 * needed if no MAGIC is kept. [In fact, having a negative ADDOFFSET
601 * would allow for slightly more buckets per arena for k=2,3.]
602 *
603 * Similarly, for chunks of size 3/2*2^k with k<=5 MAGICs would span
604 * the area up to 2^(11-k)+ADDOFFSET. For k=4 this give optimal
605 * ADDOFFSET as -7..0. For k=3 ADDOFFSET can go up to 4 (with tiny
606 * savings for negative ADDOFFSET). For k=5 ADDOFFSET can go -1..16
607 * (with no savings for negative values).
cf5c4ad8 608 *
4ad56ec9
IZ
609 * In particular, keeping ADDOFFSET 0 for sizes of chunks up to 2^6
610 * leads to tiny pessimizations in case of sizes 4, 8, 12, 24, and
611 * leads to no contradictions except for size=80 (or 96.)
cf5c4ad8 612 *
4ad56ec9
IZ
613 * However, it also makes sense to keep no magic for sizes 48 or less.
614 * This is what we do. In this case one needs ADDOFFSET>=1 also for
615 * chunksizes 12, 24, and 48, unless one gets one less chunk per
616 * arena.
617 *
618 * The algo of OV_MAGIC(block,bucket) keeps ADDOFFSET 0 until
619 * chunksize of 64, then makes it 1.
cf5c4ad8 620 *
4ad56ec9
IZ
621 * This allows for an additional optimization: the above scheme leads
622 * to giant overheads for sizes 128 or more (one whole chunk needs to
623 * be sacrifised to keep INDEX). Instead we use chunks not of size
624 * 2^k, but of size 2^k-ALIGN. If we pack these chunks at the end of
625 * the arena, then the beginnings are still in different 2^k-long
626 * sections of the arena if k>=7 for ALIGN==4, and k>=8 if ALIGN=8.
627 * Thus for k>7 the above algo of calculating the offset of the magic
628 * will still give different answers for different chunks. And to
629 * avoid the overrun of MAGIC1 into INDEX, one needs ADDOFFSET of >=1.
630 * In the case k=7 we just move the first chunk an extra ALIGN
631 * backward inside the ARENA (this is done once per arena lifetime,
632 * thus is not a big overhead). */
e8bc2b5c
GS
633# define MAX_PACKED_POW2 6
634# define MAX_PACKED (MAX_PACKED_POW2 * BUCKETS_PER_POW2 + BUCKET_POW2_SHIFT)
635# define MAX_POW2_ALGO ((1<<(MAX_PACKED_POW2 + 1)) - M_OVERHEAD)
636# define TWOK_MASK ((1<<LOG_OF_MIN_ARENA) - 1)
56431972
RB
637# define TWOK_MASKED(x) (PTR2UV(x) & ~TWOK_MASK)
638# define TWOK_SHIFT(x) (PTR2UV(x) & TWOK_MASK)
639# define OV_INDEXp(block) (INT2PTR(u_char*,TWOK_MASKED(block)))
cf5c4ad8
PP
640# define OV_INDEX(block) (*OV_INDEXp(block))
641# define OV_MAGIC(block,bucket) (*(OV_INDEXp(block) + \
e8bc2b5c
GS
642 (TWOK_SHIFT(block)>> \
643 (bucket>>BUCKET_POW2_SHIFT)) + \
644 (bucket >= MIN_NEEDS_SHIFT ? 1 : 0)))
645 /* A bucket can have a shift smaller than it size, we need to
646 shift its magic number so it will not overwrite index: */
647# ifdef BUCKETS_ROOT2
648# define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2 - 1) /* Shift 80 greater than chunk 64. */
649# else
650# define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2) /* Shift 128 greater than chunk 32. */
651# endif
cf5c4ad8
PP
652# define CHUNK_SHIFT 0
653
e8bc2b5c
GS
654/* Number of active buckets of given ordinal. */
655#ifdef IGNORE_SMALL_BAD_FREE
656#define FIRST_BUCKET_WITH_CHECK (6 * BUCKETS_PER_POW2) /* 64 */
657# define N_BLKS(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \
658 ? ((1<<LOG_OF_MIN_ARENA) - 1)/BUCKET_SIZE(bucket) \
659 : n_blks[bucket] )
660#else
661# define N_BLKS(bucket) n_blks[bucket]
662#endif
663
664static u_short n_blks[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
665 {
666# if BUCKETS_PER_POW2==1
667 0, 0,
668 (MIN_BUC_POW2==2 ? 384 : 0),
669 224, 120, 62, 31, 16, 8, 4, 2
670# else
671 0, 0, 0, 0,
672 (MIN_BUC_POW2==2 ? 384 : 0), (MIN_BUC_POW2==2 ? 384 : 0), /* 4, 4 */
673 224, 149, 120, 80, 62, 41, 31, 25, 16, 16, 8, 8, 4, 4, 2, 2
674# endif
675 };
676
677/* Shift of the first bucket with the given ordinal inside 2K chunk. */
678#ifdef IGNORE_SMALL_BAD_FREE
679# define BLK_SHIFT(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \
680 ? ((1<<LOG_OF_MIN_ARENA) \
681 - BUCKET_SIZE(bucket) * N_BLKS(bucket)) \
682 : blk_shift[bucket])
683#else
684# define BLK_SHIFT(bucket) blk_shift[bucket]
685#endif
686
687static u_short blk_shift[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
688 {
689# if BUCKETS_PER_POW2==1
690 0, 0,
691 (MIN_BUC_POW2==2 ? 512 : 0),
692 256, 128, 64, 64, /* 8 to 64 */
693 16*sizeof(union overhead),
694 8*sizeof(union overhead),
695 4*sizeof(union overhead),
696 2*sizeof(union overhead),
697# else
698 0, 0, 0, 0,
699 (MIN_BUC_POW2==2 ? 512 : 0), (MIN_BUC_POW2==2 ? 512 : 0),
700 256, 260, 128, 128, 64, 80, 64, 48, /* 8 to 96 */
701 16*sizeof(union overhead), 16*sizeof(union overhead),
702 8*sizeof(union overhead), 8*sizeof(union overhead),
703 4*sizeof(union overhead), 4*sizeof(union overhead),
704 2*sizeof(union overhead), 2*sizeof(union overhead),
705# endif
706 };
cf5c4ad8 707
5bbd1ef5
IZ
708# define NEEDED_ALIGNMENT 0x800 /* 2k boundaries */
709# define WANTED_ALIGNMENT 0x800 /* 2k boundaries */
710
cf5c4ad8
PP
711#else /* !PACK_MALLOC */
712
713# define OV_MAGIC(block,bucket) (block)->ov_magic
714# define OV_INDEX(block) (block)->ov_index
715# define CHUNK_SHIFT 1
e8bc2b5c 716# define MAX_PACKED -1
5bbd1ef5
IZ
717# define NEEDED_ALIGNMENT MEM_ALIGNBYTES
718# define WANTED_ALIGNMENT 0x400 /* 1k boundaries */
719
cf5c4ad8
PP
720#endif /* !PACK_MALLOC */
721
e8bc2b5c
GS
722#define M_OVERHEAD (sizeof(union overhead) + RSLOP)
723
724#ifdef PACK_MALLOC
725# define MEM_OVERHEAD(bucket) \
726 (bucket <= MAX_PACKED ? 0 : M_OVERHEAD)
727# ifdef SMALL_BUCKET_VIA_TABLE
728# define START_SHIFTS_BUCKET ((MAX_PACKED_POW2 + 1) * BUCKETS_PER_POW2)
729# define START_SHIFT MAX_PACKED_POW2
730# ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */
731# define SIZE_TABLE_MAX 80
732# else
733# define SIZE_TABLE_MAX 64
734# endif
735static char bucket_of[] =
736 {
737# ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */
738 /* 0 to 15 in 4-byte increments. */
739 (sizeof(void*) > 4 ? 6 : 5), /* 4/8, 5-th bucket for better reports */
740 6, /* 8 */
274c7500 741 IF_ALIGN_8(8,7), 8, /* 16/12, 16 */
e8bc2b5c
GS
742 9, 9, 10, 10, /* 24, 32 */
743 11, 11, 11, 11, /* 48 */
744 12, 12, 12, 12, /* 64 */
745 13, 13, 13, 13, /* 80 */
746 13, 13, 13, 13 /* 80 */
747# else /* !BUCKETS_ROOT2 */
748 /* 0 to 15 in 4-byte increments. */
749 (sizeof(void*) > 4 ? 3 : 2),
750 3,
751 4, 4,
752 5, 5, 5, 5,
753 6, 6, 6, 6,
754 6, 6, 6, 6
755# endif /* !BUCKETS_ROOT2 */
756 };
757# else /* !SMALL_BUCKET_VIA_TABLE */
758# define START_SHIFTS_BUCKET MIN_BUCKET
759# define START_SHIFT (MIN_BUC_POW2 - 1)
760# endif /* !SMALL_BUCKET_VIA_TABLE */
761#else /* !PACK_MALLOC */
762# define MEM_OVERHEAD(bucket) M_OVERHEAD
763# ifdef SMALL_BUCKET_VIA_TABLE
764# undef SMALL_BUCKET_VIA_TABLE
765# endif
766# define START_SHIFTS_BUCKET MIN_BUCKET
767# define START_SHIFT (MIN_BUC_POW2 - 1)
768#endif /* !PACK_MALLOC */
cf5c4ad8 769
8d063cd8 770/*
55497cff
PP
771 * Big allocations are often of the size 2^n bytes. To make them a
772 * little bit better, make blocks of size 2^n+pagesize for big n.
773 */
774
775#ifdef TWO_POT_OPTIMIZE
776
5f05dabc
PP
777# ifndef PERL_PAGESIZE
778# define PERL_PAGESIZE 4096
779# endif
e8bc2b5c
GS
780# ifndef FIRST_BIG_POW2
781# define FIRST_BIG_POW2 15 /* 32K, 16K is used too often. */
5f05dabc 782# endif
e8bc2b5c 783# define FIRST_BIG_BLOCK (1<<FIRST_BIG_POW2)
55497cff
PP
784/* If this value or more, check against bigger blocks. */
785# define FIRST_BIG_BOUND (FIRST_BIG_BLOCK - M_OVERHEAD)
786/* If less than this value, goes into 2^n-overhead-block. */
787# define LAST_SMALL_BOUND ((FIRST_BIG_BLOCK>>1) - M_OVERHEAD)
788
e8bc2b5c
GS
789# define POW2_OPTIMIZE_ADJUST(nbytes) \
790 ((nbytes >= FIRST_BIG_BOUND) ? nbytes -= PERL_PAGESIZE : 0)
791# define POW2_OPTIMIZE_SURPLUS(bucket) \
792 ((bucket >= FIRST_BIG_POW2 * BUCKETS_PER_POW2) ? PERL_PAGESIZE : 0)
793
794#else /* !TWO_POT_OPTIMIZE */
795# define POW2_OPTIMIZE_ADJUST(nbytes)
796# define POW2_OPTIMIZE_SURPLUS(bucket) 0
797#endif /* !TWO_POT_OPTIMIZE */
798
799#if defined(HAS_64K_LIMIT) && defined(PERL_CORE)
800# define BARK_64K_LIMIT(what,nbytes,size) \
801 if (nbytes > 0xffff) { \
802 PerlIO_printf(PerlIO_stderr(), \
803 "%s too large: %lx\n", what, size); \
804 my_exit(1); \
805 }
806#else /* !HAS_64K_LIMIT || !PERL_CORE */
807# define BARK_64K_LIMIT(what,nbytes,size)
808#endif /* !HAS_64K_LIMIT || !PERL_CORE */
55497cff 809
e8bc2b5c
GS
810#ifndef MIN_SBRK
811# define MIN_SBRK 2048
812#endif
813
814#ifndef FIRST_SBRK
d720c441 815# define FIRST_SBRK (48*1024)
e8bc2b5c
GS
816#endif
817
818/* Minimal sbrk in percents of what is already alloced. */
819#ifndef MIN_SBRK_FRAC
820# define MIN_SBRK_FRAC 3
821#endif
822
823#ifndef SBRK_ALLOW_FAILURES
824# define SBRK_ALLOW_FAILURES 3
825#endif
55497cff 826
e8bc2b5c
GS
827#ifndef SBRK_FAILURE_PRICE
828# define SBRK_FAILURE_PRICE 50
55497cff
PP
829#endif
830
24dd13bf
JH
831static void morecore (register int bucket);
832# if defined(DEBUGGING)
833static void botch (char *diag, char *s);
834# endif
835static void add_to_chain (void *p, MEM_SIZE size, MEM_SIZE chip);
836static void* get_from_chain (MEM_SIZE size);
837static void* get_from_bigger_buckets(int bucket, MEM_SIZE size);
838static union overhead *getpages (MEM_SIZE needed, int *nblksp, int bucket);
839static int getpages_adjacent(MEM_SIZE require);
840
e8bc2b5c
GS
841#if defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)
842
843# ifndef BIG_SIZE
844# define BIG_SIZE (1<<16) /* 64K */
845# endif
846
3541dd58 847#ifdef I_MACH_CTHREADS
772fe5b3
HM
848# undef MUTEX_LOCK
849# define MUTEX_LOCK(m) STMT_START { if (*m) mutex_lock(*m); } STMT_END
850# undef MUTEX_UNLOCK
851# define MUTEX_UNLOCK(m) STMT_START { if (*m) mutex_unlock(*m); } STMT_END
3541dd58
HM
852#endif
853
55497cff
PP
854static char *emergency_buffer;
855static MEM_SIZE emergency_buffer_size;
856
cea2e8a9
GS
857static Malloc_t
858emergency_sbrk(MEM_SIZE size)
55497cff 859{
28ac10b1
IZ
860 MEM_SIZE rsize = (((size - 1)>>LOG_OF_MIN_ARENA) + 1)<<LOG_OF_MIN_ARENA;
861
55497cff
PP
862 if (size >= BIG_SIZE) {
863 /* Give the possibility to recover: */
741df71a 864 MALLOC_UNLOCK;
1b979e0a 865 croak("Out of memory during \"large\" request for %i bytes", size);
55497cff
PP
866 }
867
28ac10b1
IZ
868 if (emergency_buffer_size >= rsize) {
869 char *old = emergency_buffer;
870
871 emergency_buffer_size -= rsize;
872 emergency_buffer += rsize;
873 return old;
874 } else {
cea2e8a9 875 dTHX;
55497cff
PP
876 /* First offense, give a possibility to recover by dieing. */
877 /* No malloc involved here: */
4a33f861 878 GV **gvp = (GV**)hv_fetch(PL_defstash, "^M", 2, 0);
55497cff
PP
879 SV *sv;
880 char *pv;
28ac10b1 881 int have = 0;
2d8e6c8d 882 STRLEN n_a;
55497cff 883
28ac10b1
IZ
884 if (emergency_buffer_size) {
885 add_to_chain(emergency_buffer, emergency_buffer_size, 0);
886 emergency_buffer_size = 0;
887 emergency_buffer = Nullch;
888 have = 1;
889 }
4a33f861 890 if (!gvp) gvp = (GV**)hv_fetch(PL_defstash, "\015", 1, 0);
55497cff 891 if (!gvp || !(sv = GvSV(*gvp)) || !SvPOK(sv)
28ac10b1
IZ
892 || (SvLEN(sv) < (1<<LOG_OF_MIN_ARENA) - M_OVERHEAD)) {
893 if (have)
894 goto do_croak;
55497cff 895 return (char *)-1; /* Now die die die... */
28ac10b1 896 }
55497cff 897 /* Got it, now detach SvPV: */
2d8e6c8d 898 pv = SvPV(sv, n_a);
55497cff 899 /* Check alignment: */
56431972 900 if ((PTR2UV(pv) - sizeof(union overhead)) & (NEEDED_ALIGNMENT - 1)) {
55497cff 901 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
bbce6d69 902 return (char *)-1; /* die die die */
55497cff
PP
903 }
904
28ac10b1
IZ
905 emergency_buffer = pv - sizeof(union overhead);
906 emergency_buffer_size = malloced_size(pv) + M_OVERHEAD;
55497cff 907 SvPOK_off(sv);
28ac10b1
IZ
908 SvPVX(sv) = Nullch;
909 SvCUR(sv) = SvLEN(sv) = 0;
55497cff 910 }
28ac10b1 911 do_croak:
741df71a 912 MALLOC_UNLOCK;
28ac10b1 913 croak("Out of memory during request for %i bytes", size);
ce70748c
GS
914 /* NOTREACHED */
915 return Nullch;
55497cff
PP
916}
917
e8bc2b5c 918#else /* !(defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)) */
55497cff 919# define emergency_sbrk(size) -1
e8bc2b5c 920#endif /* !(defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)) */
55497cff 921
c7374474
GS
922#ifndef BITS_IN_PTR
923# define BITS_IN_PTR (8*PTRSIZE)
924#endif
925
55497cff 926/*
e8bc2b5c 927 * nextf[i] is the pointer to the next free block of size 2^i. The
8d063cd8
LW
928 * smallest allocatable block is 8 bytes. The overhead information
929 * precedes the data area returned to the user.
930 */
c7374474 931#define NBUCKETS (BITS_IN_PTR*BUCKETS_PER_POW2 + 1)
8d063cd8 932static union overhead *nextf[NBUCKETS];
cf5c4ad8 933
e3663bad
GS
934#if defined(PURIFY) && !defined(USE_PERL_SBRK)
935# define USE_PERL_SBRK
936#endif
937
cf5c4ad8
PP
938#ifdef USE_PERL_SBRK
939#define sbrk(a) Perl_sbrk(a)
20ce7b12 940Malloc_t Perl_sbrk (int size);
8ac85365
NIS
941#else
942#ifdef DONT_DECLARE_STD
943#ifdef I_UNISTD
944#include <unistd.h>
945#endif
cf5c4ad8 946#else
52082926 947extern Malloc_t sbrk(int);
8ac85365 948#endif
cf5c4ad8 949#endif
8d063cd8 950
c07a80fd 951#ifdef DEBUGGING_MSTATS
8d063cd8
LW
952/*
953 * nmalloc[i] is the difference between the number of mallocs and frees
954 * for a given block size.
955 */
956static u_int nmalloc[NBUCKETS];
5f05dabc
PP
957static u_int sbrk_slack;
958static u_int start_slack;
8d063cd8
LW
959#endif
960
e8bc2b5c
GS
961static u_int goodsbrk;
962
760ac839 963#ifdef DEBUGGING
3541dd58
HM
964#undef ASSERT
965#define ASSERT(p,diag) if (!(p)) botch(diag,STRINGIFY(p)); else
cea2e8a9
GS
966static void
967botch(char *diag, char *s)
8d063cd8 968{
e8cd8248 969 dTHX;
d720c441 970 PerlIO_printf(PerlIO_stderr(), "assertion botched (%s?): %s\n", diag, s);
3028581b 971 PerlProc_abort();
8d063cd8
LW
972}
973#else
3541dd58 974#define ASSERT(p, diag)
8d063cd8
LW
975#endif
976
2304df62 977Malloc_t
86058a2d 978Perl_malloc(register size_t nbytes)
8d063cd8
LW
979{
980 register union overhead *p;
e8bc2b5c 981 register int bucket;
ee0007ab 982 register MEM_SIZE shiftr;
8d063cd8 983
c2a5c2d2 984#if defined(DEBUGGING) || defined(RCHECK)
ee0007ab 985 MEM_SIZE size = nbytes;
45d8adaa
LW
986#endif
987
e8bc2b5c 988 BARK_64K_LIMIT("Allocation",nbytes,nbytes);
45d8adaa
LW
989#ifdef DEBUGGING
990 if ((long)nbytes < 0)
cea2e8a9 991 croak("%s", "panic: malloc");
45d8adaa 992#endif
45d8adaa 993
8d063cd8
LW
994 /*
995 * Convert amount of memory requested into
996 * closest block size stored in hash buckets
997 * which satisfies request. Account for
998 * space used per block for accounting.
999 */
cf5c4ad8 1000#ifdef PACK_MALLOC
e8bc2b5c
GS
1001# ifdef SMALL_BUCKET_VIA_TABLE
1002 if (nbytes == 0)
1003 bucket = MIN_BUCKET;
1004 else if (nbytes <= SIZE_TABLE_MAX) {
1005 bucket = bucket_of[(nbytes - 1) >> BUCKET_TABLE_SHIFT];
1006 } else
1007# else
043bf814
RB
1008 if (nbytes == 0)
1009 nbytes = 1;
e8bc2b5c
GS
1010 if (nbytes <= MAX_POW2_ALGO) goto do_shifts;
1011 else
1012# endif
55497cff 1013#endif
e8bc2b5c
GS
1014 {
1015 POW2_OPTIMIZE_ADJUST(nbytes);
1016 nbytes += M_OVERHEAD;
1017 nbytes = (nbytes + 3) &~ 3;
1018 do_shifts:
1019 shiftr = (nbytes - 1) >> START_SHIFT;
1020 bucket = START_SHIFTS_BUCKET;
1021 /* apart from this loop, this is O(1) */
1022 while (shiftr >>= 1)
1023 bucket += BUCKETS_PER_POW2;
cf5c4ad8 1024 }
4ad56ec9 1025 MALLOC_LOCK;
8d063cd8
LW
1026 /*
1027 * If nothing in hash bucket right now,
1028 * request more memory from the system.
1029 */
1030 if (nextf[bucket] == NULL)
1031 morecore(bucket);
e8bc2b5c 1032 if ((p = nextf[bucket]) == NULL) {
741df71a 1033 MALLOC_UNLOCK;
55497cff 1034#ifdef PERL_CORE
0b250b9e
GS
1035 {
1036 dTHX;
1037 if (!PL_nomemok) {
1038 PerlIO_puts(PerlIO_stderr(),"Out of memory!\n");
1039 my_exit(1);
1040 }
ee0007ab 1041 }
45d8adaa 1042#endif
4ad56ec9 1043 return (NULL);
45d8adaa
LW
1044 }
1045
e8bc2b5c 1046 DEBUG_m(PerlIO_printf(Perl_debug_log,
b900a521
JH
1047 "0x%"UVxf": (%05lu) malloc %ld bytes\n",
1048 PTR2UV(p+1), (unsigned long)(PL_an++),
e8bc2b5c 1049 (long)size));
45d8adaa 1050
8d063cd8 1051 /* remove from linked list */
802004fa 1052#if defined(RCHECK)
32e30700 1053 if ((PTR2UV(p)) & (MEM_ALIGNBYTES - 1)) {
e8cd8248 1054 dTHX;
b900a521 1055 PerlIO_printf(PerlIO_stderr(),
7fa2f4f1
GS
1056 "Unaligned pointer in the free chain 0x%"UVxf"\n",
1057 PTR2UV(p));
1058 }
1059 if ((PTR2UV(p->ov_next)) & (MEM_ALIGNBYTES - 1)) {
e8cd8248 1060 dTHX;
7fa2f4f1
GS
1061 PerlIO_printf(PerlIO_stderr(),
1062 "Unaligned `next' pointer in the free "
1063 "chain 0x"UVxf" at 0x%"UVxf"\n",
1064 PTR2UV(p->ov_next), PTR2UV(p));
32e30700 1065 }
bf38876a
LW
1066#endif
1067 nextf[bucket] = p->ov_next;
4ad56ec9
IZ
1068
1069 MALLOC_UNLOCK;
1070
e8bc2b5c
GS
1071#ifdef IGNORE_SMALL_BAD_FREE
1072 if (bucket >= FIRST_BUCKET_WITH_CHECK)
1073#endif
1074 OV_MAGIC(p, bucket) = MAGIC;
cf5c4ad8
PP
1075#ifndef PACK_MALLOC
1076 OV_INDEX(p) = bucket;
1077#endif
8d063cd8
LW
1078#ifdef RCHECK
1079 /*
1080 * Record allocated size of block and
1081 * bound space with magic numbers.
1082 */
8d063cd8 1083 p->ov_rmagic = RMAGIC;
e8bc2b5c
GS
1084 if (bucket <= MAX_SHORT_BUCKET) {
1085 int i;
1086
1087 nbytes = size + M_OVERHEAD;
1088 p->ov_size = nbytes - 1;
1089 if ((i = nbytes & 3)) {
1090 i = 4 - i;
1091 while (i--)
1092 *((char *)((caddr_t)p + nbytes - RSLOP + i)) = RMAGIC_C;
1093 }
1094 nbytes = (nbytes + 3) &~ 3;
1095 *((u_int *)((caddr_t)p + nbytes - RSLOP)) = RMAGIC;
1096 }
8d063cd8 1097#endif
cf5c4ad8 1098 return ((Malloc_t)(p + CHUNK_SHIFT));
8d063cd8
LW
1099}
1100
e8bc2b5c
GS
1101static char *last_sbrk_top;
1102static char *last_op; /* This arena can be easily extended. */
1103static int sbrked_remains;
1104static int sbrk_good = SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE;
1105
1106#ifdef DEBUGGING_MSTATS
1107static int sbrks;
1108#endif
1109
1110struct chunk_chain_s {
1111 struct chunk_chain_s *next;
1112 MEM_SIZE size;
1113};
1114static struct chunk_chain_s *chunk_chain;
1115static int n_chunks;
1116static char max_bucket;
1117
1118/* Cutoff a piece of one of the chunks in the chain. Prefer smaller chunk. */
cea2e8a9
GS
1119static void *
1120get_from_chain(MEM_SIZE size)
e8bc2b5c
GS
1121{
1122 struct chunk_chain_s *elt = chunk_chain, **oldp = &chunk_chain;
1123 struct chunk_chain_s **oldgoodp = NULL;
1124 long min_remain = LONG_MAX;
1125
1126 while (elt) {
1127 if (elt->size >= size) {
1128 long remains = elt->size - size;
1129 if (remains >= 0 && remains < min_remain) {
1130 oldgoodp = oldp;
1131 min_remain = remains;
1132 }
1133 if (remains == 0) {
1134 break;
1135 }
1136 }
1137 oldp = &( elt->next );
1138 elt = elt->next;
1139 }
1140 if (!oldgoodp) return NULL;
1141 if (min_remain) {
1142 void *ret = *oldgoodp;
1143 struct chunk_chain_s *next = (*oldgoodp)->next;
1144
1145 *oldgoodp = (struct chunk_chain_s *)((char*)ret + size);
1146 (*oldgoodp)->size = min_remain;
1147 (*oldgoodp)->next = next;
1148 return ret;
1149 } else {
1150 void *ret = *oldgoodp;
1151 *oldgoodp = (*oldgoodp)->next;
1152 n_chunks--;
1153 return ret;
1154 }
1155}
1156
cea2e8a9
GS
1157static void
1158add_to_chain(void *p, MEM_SIZE size, MEM_SIZE chip)
e8bc2b5c
GS
1159{
1160 struct chunk_chain_s *next = chunk_chain;
1161 char *cp = (char*)p;
1162
1163 cp += chip;
1164 chunk_chain = (struct chunk_chain_s *)cp;
1165 chunk_chain->size = size - chip;
1166 chunk_chain->next = next;
1167 n_chunks++;
1168}
1169
cea2e8a9
GS
1170static void *
1171get_from_bigger_buckets(int bucket, MEM_SIZE size)
e8bc2b5c
GS
1172{
1173 int price = 1;
1174 static int bucketprice[NBUCKETS];
1175 while (bucket <= max_bucket) {
1176 /* We postpone stealing from bigger buckets until we want it
1177 often enough. */
1178 if (nextf[bucket] && bucketprice[bucket]++ >= price) {
1179 /* Steal it! */
1180 void *ret = (void*)(nextf[bucket] - 1 + CHUNK_SHIFT);
1181 bucketprice[bucket] = 0;
1182 if (((char*)nextf[bucket]) - M_OVERHEAD == last_op) {
1183 last_op = NULL; /* Disable optimization */
1184 }
1185 nextf[bucket] = nextf[bucket]->ov_next;
1186#ifdef DEBUGGING_MSTATS
1187 nmalloc[bucket]--;
1188 start_slack -= M_OVERHEAD;
1189#endif
1190 add_to_chain(ret, (BUCKET_SIZE(bucket) +
1191 POW2_OPTIMIZE_SURPLUS(bucket)),
1192 size);
1193 return ret;
1194 }
1195 bucket++;
1196 }
1197 return NULL;
1198}
1199
cea2e8a9 1200static union overhead *
c7374474 1201getpages(MEM_SIZE needed, int *nblksp, int bucket)
fa423c5b
IZ
1202{
1203 /* Need to do (possibly expensive) system call. Try to
1204 optimize it for rare calling. */
1205 MEM_SIZE require = needed - sbrked_remains;
1206 char *cp;
1207 union overhead *ovp;
c7374474 1208 MEM_SIZE slack = 0;
fa423c5b
IZ
1209
1210 if (sbrk_good > 0) {
1211 if (!last_sbrk_top && require < FIRST_SBRK)
1212 require = FIRST_SBRK;
1213 else if (require < MIN_SBRK) require = MIN_SBRK;
1214
1215 if (require < goodsbrk * MIN_SBRK_FRAC / 100)
1216 require = goodsbrk * MIN_SBRK_FRAC / 100;
1217 require = ((require - 1 + MIN_SBRK) / MIN_SBRK) * MIN_SBRK;
1218 } else {
1219 require = needed;
1220 last_sbrk_top = 0;
1221 sbrked_remains = 0;
1222 }
1223
1224 DEBUG_m(PerlIO_printf(Perl_debug_log,
1225 "sbrk(%ld) for %ld-byte-long arena\n",
1226 (long)require, (long) needed));
1227 cp = (char *)sbrk(require);
1228#ifdef DEBUGGING_MSTATS
1229 sbrks++;
1230#endif
1231 if (cp == last_sbrk_top) {
1232 /* Common case, anything is fine. */
1233 sbrk_good++;
1234 ovp = (union overhead *) (cp - sbrked_remains);
e9397286 1235 last_op = cp - sbrked_remains;
fa423c5b
IZ
1236 sbrked_remains = require - (needed - sbrked_remains);
1237 } else if (cp == (char *)-1) { /* no more room! */
1238 ovp = (union overhead *)emergency_sbrk(needed);
1239 if (ovp == (union overhead *)-1)
1240 return 0;
e9397286
GS
1241 if (((char*)ovp) > last_op) { /* Cannot happen with current emergency_sbrk() */
1242 last_op = 0;
1243 }
fa423c5b
IZ
1244 return ovp;
1245 } else { /* Non-continuous or first sbrk(). */
1246 long add = sbrked_remains;
1247 char *newcp;
1248
1249 if (sbrked_remains) { /* Put rest into chain, we
1250 cannot use it right now. */
1251 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1252 sbrked_remains, 0);
1253 }
1254
1255 /* Second, check alignment. */
1256 slack = 0;
1257
61ae2fbf 1258#if !defined(atarist) && !defined(__MINT__) /* on the atari we dont have to worry about this */
fa423c5b 1259# ifndef I286 /* The sbrk(0) call on the I286 always returns the next segment */
5bbd1ef5
IZ
1260 /* WANTED_ALIGNMENT may be more than NEEDED_ALIGNMENT, but this may
1261 improve performance of memory access. */
56431972
RB
1262 if (PTR2UV(cp) & (WANTED_ALIGNMENT - 1)) { /* Not aligned. */
1263 slack = WANTED_ALIGNMENT - (PTR2UV(cp) & (WANTED_ALIGNMENT - 1));
fa423c5b
IZ
1264 add += slack;
1265 }
1266# endif
61ae2fbf 1267#endif /* !atarist && !MINT */
fa423c5b
IZ
1268
1269 if (add) {
1270 DEBUG_m(PerlIO_printf(Perl_debug_log,
1271 "sbrk(%ld) to fix non-continuous/off-page sbrk:\n\t%ld for alignement,\t%ld were assumed to come from the tail of the previous sbrk\n",
1272 (long)add, (long) slack,
1273 (long) sbrked_remains));
1274 newcp = (char *)sbrk(add);
1275#if defined(DEBUGGING_MSTATS)
1276 sbrks++;
1277 sbrk_slack += add;
1278#endif
1279 if (newcp != cp + require) {
1280 /* Too bad: even rounding sbrk() is not continuous.*/
1281 DEBUG_m(PerlIO_printf(Perl_debug_log,
1282 "failed to fix bad sbrk()\n"));
1283#ifdef PACK_MALLOC
1284 if (slack) {
741df71a 1285 MALLOC_UNLOCK;
5bbd1ef5 1286 fatalcroak("panic: Off-page sbrk\n");
fa423c5b
IZ
1287 }
1288#endif
1289 if (sbrked_remains) {
1290 /* Try again. */
1291#if defined(DEBUGGING_MSTATS)
1292 sbrk_slack += require;
1293#endif
1294 require = needed;
1295 DEBUG_m(PerlIO_printf(Perl_debug_log,
1296 "straight sbrk(%ld)\n",
1297 (long)require));
1298 cp = (char *)sbrk(require);
1299#ifdef DEBUGGING_MSTATS
1300 sbrks++;
1301#endif
1302 if (cp == (char *)-1)
1303 return 0;
1304 }
1305 sbrk_good = -1; /* Disable optimization!
1306 Continue with not-aligned... */
1307 } else {
1308 cp += slack;
1309 require += sbrked_remains;
1310 }
1311 }
1312
1313 if (last_sbrk_top) {
1314 sbrk_good -= SBRK_FAILURE_PRICE;
1315 }
1316
1317 ovp = (union overhead *) cp;
1318 /*
1319 * Round up to minimum allocation size boundary
1320 * and deduct from block count to reflect.
1321 */
1322
5bbd1ef5 1323# if NEEDED_ALIGNMENT > MEM_ALIGNBYTES
56431972 1324 if (PTR2UV(ovp) & (NEEDED_ALIGNMENT - 1))
5bbd1ef5
IZ
1325 fatalcroak("Misalignment of sbrk()\n");
1326 else
1327# endif
fa423c5b 1328#ifndef I286 /* Again, this should always be ok on an 80286 */
56431972 1329 if (PTR2UV(ovp) & (MEM_ALIGNBYTES - 1)) {
fa423c5b
IZ
1330 DEBUG_m(PerlIO_printf(Perl_debug_log,
1331 "fixing sbrk(): %d bytes off machine alignement\n",
56431972
RB
1332 (int)(PTR2UV(ovp) & (MEM_ALIGNBYTES - 1))));
1333 ovp = INT2PTR(union overhead *,(PTR2UV(ovp) + MEM_ALIGNBYTES) &
5bbd1ef5 1334 (MEM_ALIGNBYTES - 1));
fa423c5b
IZ
1335 (*nblksp)--;
1336# if defined(DEBUGGING_MSTATS)
1337 /* This is only approx. if TWO_POT_OPTIMIZE: */
5bbd1ef5 1338 sbrk_slack += (1 << (bucket >> BUCKET_POW2_SHIFT));
fa423c5b
IZ
1339# endif
1340 }
1341#endif
5bbd1ef5 1342 ; /* Finish `else' */
fa423c5b 1343 sbrked_remains = require - needed;
e9397286 1344 last_op = cp;
fa423c5b
IZ
1345 }
1346 last_sbrk_top = cp + require;
fa423c5b
IZ
1347#ifdef DEBUGGING_MSTATS
1348 goodsbrk += require;
1349#endif
1350 return ovp;
1351}
1352
cea2e8a9 1353static int
c7374474 1354getpages_adjacent(MEM_SIZE require)
fa423c5b
IZ
1355{
1356 if (require <= sbrked_remains) {
1357 sbrked_remains -= require;
1358 } else {
1359 char *cp;
1360
1361 require -= sbrked_remains;
1362 /* We do not try to optimize sbrks here, we go for place. */
1363 cp = (char*) sbrk(require);
1364#ifdef DEBUGGING_MSTATS
1365 sbrks++;
1366 goodsbrk += require;
1367#endif
1368 if (cp == last_sbrk_top) {
1369 sbrked_remains = 0;
1370 last_sbrk_top = cp + require;
1371 } else {
28ac10b1
IZ
1372 if (cp == (char*)-1) { /* Out of memory */
1373#ifdef DEBUGGING_MSTATS
1374 goodsbrk -= require;
1375#endif
1376 return 0;
1377 }
fa423c5b
IZ
1378 /* Report the failure: */
1379 if (sbrked_remains)
1380 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1381 sbrked_remains, 0);
1382 add_to_chain((void*)cp, require, 0);
1383 sbrk_good -= SBRK_FAILURE_PRICE;
1384 sbrked_remains = 0;
1385 last_sbrk_top = 0;
1386 last_op = 0;
1387 return 0;
1388 }
1389 }
1390
1391 return 1;
1392}
1393
8d063cd8
LW
1394/*
1395 * Allocate more memory to the indicated bucket.
1396 */
cea2e8a9
GS
1397static void
1398morecore(register int bucket)
8d063cd8 1399{
72aaf631 1400 register union overhead *ovp;
8d063cd8 1401 register int rnu; /* 2^rnu bytes will be requested */
fa423c5b 1402 int nblks; /* become nblks blocks of the desired size */
bbce6d69 1403 register MEM_SIZE siz, needed;
8d063cd8
LW
1404
1405 if (nextf[bucket])
1406 return;
e8bc2b5c 1407 if (bucket == sizeof(MEM_SIZE)*8*BUCKETS_PER_POW2) {
741df71a 1408 MALLOC_UNLOCK;
d720c441 1409 croak("%s", "Out of memory during ridiculously large request");
55497cff 1410 }
d720c441 1411 if (bucket > max_bucket)
e8bc2b5c 1412 max_bucket = bucket;
d720c441 1413
e8bc2b5c
GS
1414 rnu = ( (bucket <= (LOG_OF_MIN_ARENA << BUCKET_POW2_SHIFT))
1415 ? LOG_OF_MIN_ARENA
1416 : (bucket >> BUCKET_POW2_SHIFT) );
1417 /* This may be overwritten later: */
1418 nblks = 1 << (rnu - (bucket >> BUCKET_POW2_SHIFT)); /* how many blocks to get */
1419 needed = ((MEM_SIZE)1 << rnu) + POW2_OPTIMIZE_SURPLUS(bucket);
1420 if (nextf[rnu << BUCKET_POW2_SHIFT]) { /* 2048b bucket. */
1421 ovp = nextf[rnu << BUCKET_POW2_SHIFT] - 1 + CHUNK_SHIFT;
1422 nextf[rnu << BUCKET_POW2_SHIFT]
1423 = nextf[rnu << BUCKET_POW2_SHIFT]->ov_next;
1424#ifdef DEBUGGING_MSTATS
1425 nmalloc[rnu << BUCKET_POW2_SHIFT]--;
1426 start_slack -= M_OVERHEAD;
1427#endif
1428 DEBUG_m(PerlIO_printf(Perl_debug_log,
1429 "stealing %ld bytes from %ld arena\n",
1430 (long) needed, (long) rnu << BUCKET_POW2_SHIFT));
1431 } else if (chunk_chain
1432 && (ovp = (union overhead*) get_from_chain(needed))) {
1433 DEBUG_m(PerlIO_printf(Perl_debug_log,
1434 "stealing %ld bytes from chain\n",
1435 (long) needed));
d720c441
IZ
1436 } else if ( (ovp = (union overhead*)
1437 get_from_bigger_buckets((rnu << BUCKET_POW2_SHIFT) + 1,
1438 needed)) ) {
e8bc2b5c
GS
1439 DEBUG_m(PerlIO_printf(Perl_debug_log,
1440 "stealing %ld bytes from bigger buckets\n",
1441 (long) needed));
1442 } else if (needed <= sbrked_remains) {
1443 ovp = (union overhead *)(last_sbrk_top - sbrked_remains);
1444 sbrked_remains -= needed;
1445 last_op = (char*)ovp;
fa423c5b
IZ
1446 } else
1447 ovp = getpages(needed, &nblks, bucket);
e8bc2b5c 1448
fa423c5b
IZ
1449 if (!ovp)
1450 return;
e8bc2b5c 1451
8d063cd8
LW
1452 /*
1453 * Add new memory allocated to that on
1454 * free list for this hash bucket.
1455 */
e8bc2b5c 1456 siz = BUCKET_SIZE(bucket);
cf5c4ad8 1457#ifdef PACK_MALLOC
72aaf631 1458 *(u_char*)ovp = bucket; /* Fill index. */
e8bc2b5c
GS
1459 if (bucket <= MAX_PACKED) {
1460 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1461 nblks = N_BLKS(bucket);
cf5c4ad8 1462# ifdef DEBUGGING_MSTATS
e8bc2b5c 1463 start_slack += BLK_SHIFT(bucket);
cf5c4ad8 1464# endif
e8bc2b5c
GS
1465 } else if (bucket < LOG_OF_MIN_ARENA * BUCKETS_PER_POW2) {
1466 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
cf5c4ad8 1467 siz -= sizeof(union overhead);
72aaf631 1468 } else ovp++; /* One chunk per block. */
e8bc2b5c 1469#endif /* PACK_MALLOC */
72aaf631 1470 nextf[bucket] = ovp;
5f05dabc
PP
1471#ifdef DEBUGGING_MSTATS
1472 nmalloc[bucket] += nblks;
e8bc2b5c
GS
1473 if (bucket > MAX_PACKED) {
1474 start_slack += M_OVERHEAD * nblks;
1475 }
5f05dabc 1476#endif
8d063cd8 1477 while (--nblks > 0) {
72aaf631
MB
1478 ovp->ov_next = (union overhead *)((caddr_t)ovp + siz);
1479 ovp = (union overhead *)((caddr_t)ovp + siz);
8d063cd8 1480 }
8595d6f1 1481 /* Not all sbrks return zeroed memory.*/
72aaf631 1482 ovp->ov_next = (union overhead *)NULL;
cf5c4ad8 1483#ifdef PACK_MALLOC
e8bc2b5c
GS
1484 if (bucket == 7*BUCKETS_PER_POW2) { /* Special case, explanation is above. */
1485 union overhead *n_op = nextf[7*BUCKETS_PER_POW2]->ov_next;
1486 nextf[7*BUCKETS_PER_POW2] =
1487 (union overhead *)((caddr_t)nextf[7*BUCKETS_PER_POW2]
1488 - sizeof(union overhead));
1489 nextf[7*BUCKETS_PER_POW2]->ov_next = n_op;
cf5c4ad8
PP
1490 }
1491#endif /* !PACK_MALLOC */
8d063cd8
LW
1492}
1493
94b6baf5 1494Free_t
86058a2d 1495Perl_mfree(void *mp)
cea2e8a9 1496{
ee0007ab 1497 register MEM_SIZE size;
72aaf631 1498 register union overhead *ovp;
352d5a3a 1499 char *cp = (char*)mp;
cf5c4ad8
PP
1500#ifdef PACK_MALLOC
1501 u_char bucket;
1502#endif
8d063cd8 1503
e8bc2b5c 1504 DEBUG_m(PerlIO_printf(Perl_debug_log,
b900a521
JH
1505 "0x%"UVxf": (%05lu) free\n",
1506 PTR2UV(cp), (unsigned long)(PL_an++)));
45d8adaa 1507
cf5c4ad8
PP
1508 if (cp == NULL)
1509 return;
72aaf631 1510 ovp = (union overhead *)((caddr_t)cp
e8bc2b5c 1511 - sizeof (union overhead) * CHUNK_SHIFT);
cf5c4ad8 1512#ifdef PACK_MALLOC
72aaf631 1513 bucket = OV_INDEX(ovp);
cf5c4ad8 1514#endif
e8bc2b5c
GS
1515#ifdef IGNORE_SMALL_BAD_FREE
1516 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
1517 && (OV_MAGIC(ovp, bucket) != MAGIC))
1518#else
1519 if (OV_MAGIC(ovp, bucket) != MAGIC)
1520#endif
1521 {
68dc0745 1522 static int bad_free_warn = -1;
cf5c4ad8 1523 if (bad_free_warn == -1) {
e8cd8248 1524 dTHX;
5fd9e9a4 1525 char *pbf = PerlEnv_getenv("PERL_BADFREE");
cf5c4ad8
PP
1526 bad_free_warn = (pbf) ? atoi(pbf) : 1;
1527 }
1528 if (!bad_free_warn)
1529 return;
8990e307 1530#ifdef RCHECK
2ba999ec 1531#ifdef PERL_CORE
e8cd8248
GS
1532 {
1533 dTHX;
1534 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1d860e85 1535 Perl_warner(aTHX_ WARN_MALLOC, "%s free() ignored",
e8cd8248
GS
1536 ovp->ov_rmagic == RMAGIC - 1 ?
1537 "Duplicate" : "Bad");
2ba999ec 1538 }
e476b1b5 1539#else
2ba999ec
GS
1540 warn("%s free() ignored",
1541 ovp->ov_rmagic == RMAGIC - 1 ? "Duplicate" : "Bad");
e476b1b5
GS
1542#endif
1543#else
1544#ifdef PERL_CORE
2ba999ec
GS
1545 {
1546 dTHX;
1d860e85
GS
1547 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1548 Perl_warner(aTHX_ WARN_MALLOC, "%s", "Bad free() ignored");
2ba999ec 1549 }
8990e307 1550#else
2ba999ec 1551 warn("%s", "Bad free() ignored");
8990e307 1552#endif
e476b1b5 1553#endif
8d063cd8 1554 return; /* sanity */
e8bc2b5c 1555 }
8d063cd8 1556#ifdef RCHECK
3541dd58 1557 ASSERT(ovp->ov_rmagic == RMAGIC, "chunk's head overwrite");
e8bc2b5c
GS
1558 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
1559 int i;
1560 MEM_SIZE nbytes = ovp->ov_size + 1;
1561
1562 if ((i = nbytes & 3)) {
1563 i = 4 - i;
1564 while (i--) {
3541dd58 1565 ASSERT(*((char *)((caddr_t)ovp + nbytes - RSLOP + i))
d720c441 1566 == RMAGIC_C, "chunk's tail overwrite");
e8bc2b5c
GS
1567 }
1568 }
1569 nbytes = (nbytes + 3) &~ 3;
3541dd58 1570 ASSERT(*(u_int *)((caddr_t)ovp + nbytes - RSLOP) == RMAGIC, "chunk's tail overwrite");
e8bc2b5c 1571 }
72aaf631 1572 ovp->ov_rmagic = RMAGIC - 1;
8d063cd8 1573#endif
3541dd58 1574 ASSERT(OV_INDEX(ovp) < NBUCKETS, "chunk's head overwrite");
72aaf631 1575 size = OV_INDEX(ovp);
4ad56ec9
IZ
1576
1577 MALLOC_LOCK;
72aaf631
MB
1578 ovp->ov_next = nextf[size];
1579 nextf[size] = ovp;
741df71a 1580 MALLOC_UNLOCK;
8d063cd8
LW
1581}
1582
4ad56ec9
IZ
1583/* There is no need to do any locking in realloc (with an exception of
1584 trying to grow in place if we are at the end of the chain).
1585 If somebody calls us from a different thread with the same address,
1586 we are sole anyway. */
8d063cd8 1587
2304df62 1588Malloc_t
86058a2d 1589Perl_realloc(void *mp, size_t nbytes)
cea2e8a9 1590{
ee0007ab 1591 register MEM_SIZE onb;
72aaf631 1592 union overhead *ovp;
d720c441
IZ
1593 char *res;
1594 int prev_bucket;
e8bc2b5c 1595 register int bucket;
4ad56ec9
IZ
1596 int incr; /* 1 if does not fit, -1 if "easily" fits in a
1597 smaller bucket, otherwise 0. */
352d5a3a 1598 char *cp = (char*)mp;
8d063cd8 1599
e8bc2b5c 1600#if defined(DEBUGGING) || !defined(PERL_CORE)
ee0007ab 1601 MEM_SIZE size = nbytes;
45d8adaa 1602
45d8adaa 1603 if ((long)nbytes < 0)
cea2e8a9 1604 croak("%s", "panic: realloc");
45d8adaa 1605#endif
e8bc2b5c
GS
1606
1607 BARK_64K_LIMIT("Reallocation",nbytes,size);
1608 if (!cp)
86058a2d 1609 return Perl_malloc(nbytes);
45d8adaa 1610
72aaf631 1611 ovp = (union overhead *)((caddr_t)cp
e8bc2b5c
GS
1612 - sizeof (union overhead) * CHUNK_SHIFT);
1613 bucket = OV_INDEX(ovp);
4ad56ec9 1614
e8bc2b5c 1615#ifdef IGNORE_SMALL_BAD_FREE
4ad56ec9
IZ
1616 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
1617 && (OV_MAGIC(ovp, bucket) != MAGIC))
e8bc2b5c 1618#else
4ad56ec9 1619 if (OV_MAGIC(ovp, bucket) != MAGIC)
e8bc2b5c 1620#endif
4ad56ec9
IZ
1621 {
1622 static int bad_free_warn = -1;
1623 if (bad_free_warn == -1) {
e8cd8248 1624 dTHX;
4ad56ec9
IZ
1625 char *pbf = PerlEnv_getenv("PERL_BADFREE");
1626 bad_free_warn = (pbf) ? atoi(pbf) : 1;
1627 }
1628 if (!bad_free_warn)
ce70748c 1629 return Nullch;
4ad56ec9 1630#ifdef RCHECK
2ba999ec 1631#ifdef PERL_CORE
e8cd8248
GS
1632 {
1633 dTHX;
1634 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1d860e85 1635 Perl_warner(aTHX_ WARN_MALLOC, "%srealloc() %signored",
e8cd8248
GS
1636 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
1637 ovp->ov_rmagic == RMAGIC - 1
1638 ? "of freed memory " : "");
2ba999ec 1639 }
e476b1b5 1640#else
2ba999ec
GS
1641 warn("%srealloc() %signored",
1642 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
1643 ovp->ov_rmagic == RMAGIC - 1 ? "of freed memory " : "");
e476b1b5
GS
1644#endif
1645#else
1646#ifdef PERL_CORE
2ba999ec
GS
1647 {
1648 dTHX;
1d860e85
GS
1649 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1650 Perl_warner(aTHX_ WARN_MALLOC, "%s",
1651 "Bad realloc() ignored");
2ba999ec 1652 }
4ad56ec9 1653#else
2ba999ec 1654 warn("%s", "Bad realloc() ignored");
4ad56ec9 1655#endif
e476b1b5 1656#endif
ce70748c 1657 return Nullch; /* sanity */
4ad56ec9
IZ
1658 }
1659
e8bc2b5c 1660 onb = BUCKET_SIZE_REAL(bucket);
55497cff
PP
1661 /*
1662 * avoid the copy if same size block.
e8bc2b5c
GS
1663 * We are not agressive with boundary cases. Note that it might
1664 * (for a small number of cases) give false negative if
55497cff 1665 * both new size and old one are in the bucket for
e8bc2b5c
GS
1666 * FIRST_BIG_POW2, but the new one is near the lower end.
1667 *
1668 * We do not try to go to 1.5 times smaller bucket so far.
55497cff 1669 */
e8bc2b5c
GS
1670 if (nbytes > onb) incr = 1;
1671 else {
1672#ifdef DO_NOT_TRY_HARDER_WHEN_SHRINKING
1673 if ( /* This is a little bit pessimal if PACK_MALLOC: */
1674 nbytes > ( (onb >> 1) - M_OVERHEAD )
1675# ifdef TWO_POT_OPTIMIZE
1676 || (bucket == FIRST_BIG_POW2 && nbytes >= LAST_SMALL_BOUND )
1677# endif
1678 )
1679#else /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
1680 prev_bucket = ( (bucket > MAX_PACKED + 1)
1681 ? bucket - BUCKETS_PER_POW2
1682 : bucket - 1);
1683 if (nbytes > BUCKET_SIZE_REAL(prev_bucket))
1684#endif /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
1685 incr = 0;
1686 else incr = -1;
1687 }
2ce36478 1688#ifdef STRESS_REALLOC
4ad56ec9 1689 goto hard_way;
2ce36478 1690#endif
4ad56ec9 1691 if (incr == 0) {
852c2e52 1692 inplace_label:
a687059c
LW
1693#ifdef RCHECK
1694 /*
1695 * Record new allocated size of block and
1696 * bound space with magic numbers.
1697 */
72aaf631 1698 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
e8bc2b5c
GS
1699 int i, nb = ovp->ov_size + 1;
1700
1701 if ((i = nb & 3)) {
1702 i = 4 - i;
1703 while (i--) {
3541dd58 1704 ASSERT(*((char *)((caddr_t)ovp + nb - RSLOP + i)) == RMAGIC_C, "chunk's tail overwrite");
e8bc2b5c
GS
1705 }
1706 }
1707 nb = (nb + 3) &~ 3;
3541dd58 1708 ASSERT(*(u_int *)((caddr_t)ovp + nb - RSLOP) == RMAGIC, "chunk's tail overwrite");
a687059c
LW
1709 /*
1710 * Convert amount of memory requested into
1711 * closest block size stored in hash buckets
1712 * which satisfies request. Account for
1713 * space used per block for accounting.
1714 */
cf5c4ad8 1715 nbytes += M_OVERHEAD;
72aaf631 1716 ovp->ov_size = nbytes - 1;
e8bc2b5c
GS
1717 if ((i = nbytes & 3)) {
1718 i = 4 - i;
1719 while (i--)
1720 *((char *)((caddr_t)ovp + nbytes - RSLOP + i))
1721 = RMAGIC_C;
1722 }
1723 nbytes = (nbytes + 3) &~ 3;
72aaf631 1724 *((u_int *)((caddr_t)ovp + nbytes - RSLOP)) = RMAGIC;
a687059c
LW
1725 }
1726#endif
45d8adaa 1727 res = cp;
42ac124e 1728 DEBUG_m(PerlIO_printf(Perl_debug_log,
b900a521
JH
1729 "0x%"UVxf": (%05lu) realloc %ld bytes inplace\n",
1730 PTR2UV(res),(unsigned long)(PL_an++),
42ac124e 1731 (long)size));
e8bc2b5c
GS
1732 } else if (incr == 1 && (cp - M_OVERHEAD == last_op)
1733 && (onb > (1 << LOG_OF_MIN_ARENA))) {
1734 MEM_SIZE require, newarena = nbytes, pow;
1735 int shiftr;
1736
1737 POW2_OPTIMIZE_ADJUST(newarena);
1738 newarena = newarena + M_OVERHEAD;
1739 /* newarena = (newarena + 3) &~ 3; */
1740 shiftr = (newarena - 1) >> LOG_OF_MIN_ARENA;
1741 pow = LOG_OF_MIN_ARENA + 1;
1742 /* apart from this loop, this is O(1) */
1743 while (shiftr >>= 1)
1744 pow++;
1745 newarena = (1 << pow) + POW2_OPTIMIZE_SURPLUS(pow * BUCKETS_PER_POW2);
1746 require = newarena - onb - M_OVERHEAD;
1747
4ad56ec9
IZ
1748 MALLOC_LOCK;
1749 if (cp - M_OVERHEAD == last_op /* We *still* are the last chunk */
1750 && getpages_adjacent(require)) {
e8bc2b5c 1751#ifdef DEBUGGING_MSTATS
fa423c5b
IZ
1752 nmalloc[bucket]--;
1753 nmalloc[pow * BUCKETS_PER_POW2]++;
e8bc2b5c 1754#endif
4d6cd4d8 1755 *(cp - M_OVERHEAD) = pow * BUCKETS_PER_POW2; /* Fill index. */
4ad56ec9 1756 MALLOC_UNLOCK;
fa423c5b 1757 goto inplace_label;
4ad56ec9
IZ
1758 } else {
1759 MALLOC_UNLOCK;
fa423c5b 1760 goto hard_way;
4ad56ec9 1761 }
e8bc2b5c
GS
1762 } else {
1763 hard_way:
42ac124e 1764 DEBUG_m(PerlIO_printf(Perl_debug_log,
b900a521
JH
1765 "0x%"UVxf": (%05lu) realloc %ld bytes the hard way\n",
1766 PTR2UV(cp),(unsigned long)(PL_an++),
42ac124e 1767 (long)size));
86058a2d 1768 if ((res = (char*)Perl_malloc(nbytes)) == NULL)
e8bc2b5c
GS
1769 return (NULL);
1770 if (cp != res) /* common optimization */
1771 Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char);
4ad56ec9 1772 Perl_mfree(cp);
45d8adaa 1773 }
2304df62 1774 return ((Malloc_t)res);
8d063cd8
LW
1775}
1776
cf5c4ad8 1777Malloc_t
86058a2d 1778Perl_calloc(register size_t elements, register size_t size)
cf5c4ad8
PP
1779{
1780 long sz = elements * size;
86058a2d 1781 Malloc_t p = Perl_malloc(sz);
cf5c4ad8
PP
1782
1783 if (p) {
1784 memset((void*)p, 0, sz);
1785 }
1786 return p;
1787}
1788
4ad56ec9
IZ
1789char *
1790Perl_strdup(const char *s)
1791{
1792 MEM_SIZE l = strlen(s);
b48f1ba5 1793 char *s1 = (char *)Perl_malloc(l+1);
4ad56ec9 1794
b48f1ba5 1795 Copy(s, s1, (MEM_SIZE)(l+1), char);
4ad56ec9
IZ
1796 return s1;
1797}
1798
1799#ifdef PERL_CORE
1800int
1801Perl_putenv(char *a)
1802{
1803 /* Sometimes system's putenv conflicts with my_setenv() - this is system
1804 malloc vs Perl's free(). */
1805 dTHX;
1806 char *var;
1807 char *val = a;
1808 MEM_SIZE l;
1809 char buf[80];
1810
1811 while (*val && *val != '=')
1812 val++;
1813 if (!*val)
1814 return -1;
1815 l = val - a;
1816 if (l < sizeof(buf))
1817 var = buf;
1818 else
1819 var = Perl_malloc(l + 1);
1820 Copy(a, var, l, char);
b48f1ba5
GS
1821 var[l + 1] = 0;
1822 my_setenv(var, val+1);
4ad56ec9
IZ
1823 if (var != buf)
1824 Perl_mfree(var);
1825 return 0;
1826}
1827# endif
1828
e8bc2b5c 1829MEM_SIZE
cea2e8a9 1830Perl_malloced_size(void *p)
e8bc2b5c 1831{
8d6dde3e
IZ
1832 union overhead *ovp = (union overhead *)
1833 ((caddr_t)p - sizeof (union overhead) * CHUNK_SHIFT);
1834 int bucket = OV_INDEX(ovp);
1835#ifdef RCHECK
1836 /* The caller wants to have a complete control over the chunk,
1837 disable the memory checking inside the chunk. */
1838 if (bucket <= MAX_SHORT_BUCKET) {
1839 MEM_SIZE size = BUCKET_SIZE_REAL(bucket);
1840 ovp->ov_size = size + M_OVERHEAD - 1;
1841 *((u_int *)((caddr_t)ovp + size + M_OVERHEAD - RSLOP)) = RMAGIC;
1842 }
1843#endif
e8bc2b5c
GS
1844 return BUCKET_SIZE_REAL(bucket);
1845}
1846
e8bc2b5c
GS
1847# ifdef BUCKETS_ROOT2
1848# define MIN_EVEN_REPORT 6
1849# else
1850# define MIN_EVEN_REPORT MIN_BUCKET
1851# endif
827e134a
GS
1852
1853int
1854Perl_get_mstats(pTHX_ perl_mstats_t *buf, int buflen, int level)
8d063cd8 1855{
df31f264 1856#ifdef DEBUGGING_MSTATS
8d063cd8
LW
1857 register int i, j;
1858 register union overhead *p;
4ad56ec9 1859 struct chunk_chain_s* nextchain;
8d063cd8 1860
827e134a
GS
1861 buf->topbucket = buf->topbucket_ev = buf->topbucket_odd
1862 = buf->totfree = buf->total = buf->total_chain = 0;
1863
1864 buf->minbucket = MIN_BUCKET;
4ad56ec9 1865 MALLOC_LOCK;
e8bc2b5c 1866 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
8d063cd8
LW
1867 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
1868 ;
827e134a
GS
1869 if (i < buflen) {
1870 buf->nfree[i] = j;
1871 buf->ntotal[i] = nmalloc[i];
1872 }
1873 buf->totfree += j * BUCKET_SIZE_REAL(i);
1874 buf->total += nmalloc[i] * BUCKET_SIZE_REAL(i);
e8bc2b5c 1875 if (nmalloc[i]) {
827e134a
GS
1876 i % 2 ? (buf->topbucket_odd = i) : (buf->topbucket_ev = i);
1877 buf->topbucket = i;
e8bc2b5c 1878 }
c07a80fd 1879 }
4ad56ec9
IZ
1880 nextchain = chunk_chain;
1881 while (nextchain) {
827e134a 1882 buf->total_chain += nextchain->size;
4ad56ec9
IZ
1883 nextchain = nextchain->next;
1884 }
827e134a
GS
1885 buf->total_sbrk = goodsbrk + sbrk_slack;
1886 buf->sbrks = sbrks;
1887 buf->sbrk_good = sbrk_good;
1888 buf->sbrk_slack = sbrk_slack;
1889 buf->start_slack = start_slack;
1890 buf->sbrked_remains = sbrked_remains;
4ad56ec9 1891 MALLOC_UNLOCK;
827e134a
GS
1892 if (level) {
1893 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
1894 if (i >= buflen)
1895 break;
1896 buf->bucket_mem_size[i] = BUCKET_SIZE(i);
1897 buf->bucket_available_size[i] = BUCKET_SIZE_REAL(i);
1898 }
1899 }
1900#endif /* defined DEBUGGING_MSTATS */
fe52b3b7 1901 return 0; /* XXX unused */
827e134a
GS
1902}
1903/*
1904 * mstats - print out statistics about malloc
1905 *
1906 * Prints two lines of numbers, one showing the length of the free list
1907 * for each size category, the second showing the number of mallocs -
1908 * frees for each size category.
1909 */
1910void
1911Perl_dump_mstats(pTHX_ char *s)
1912{
1913#ifdef DEBUGGING_MSTATS
1914 register int i, j;
1915 register union overhead *p;
1916 perl_mstats_t buffer;
1917 unsigned long nf[NBUCKETS];
1918 unsigned long nt[NBUCKETS];
1919 struct chunk_chain_s* nextchain;
1920
1921 buffer.nfree = nf;
1922 buffer.ntotal = nt;
1923 get_mstats(&buffer, NBUCKETS, 0);
1924
c07a80fd 1925 if (s)
bf49b057 1926 PerlIO_printf(Perl_error_log,
d720c441 1927 "Memory allocation statistics %s (buckets %ld(%ld)..%ld(%ld)\n",
e8bc2b5c 1928 s,
d720c441
IZ
1929 (long)BUCKET_SIZE_REAL(MIN_BUCKET),
1930 (long)BUCKET_SIZE(MIN_BUCKET),
827e134a
GS
1931 (long)BUCKET_SIZE_REAL(buffer.topbucket),
1932 (long)BUCKET_SIZE(buffer.topbucket));
76cfd9aa 1933 PerlIO_printf(Perl_error_log, "%8ld free:", buffer.totfree);
827e134a 1934 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
bf49b057 1935 PerlIO_printf(Perl_error_log,
e8bc2b5c
GS
1936 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
1937 ? " %5d"
1938 : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")),
827e134a 1939 buffer.nfree[i]);
e8bc2b5c
GS
1940 }
1941#ifdef BUCKETS_ROOT2
bf49b057 1942 PerlIO_printf(Perl_error_log, "\n\t ");
827e134a 1943 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
bf49b057 1944 PerlIO_printf(Perl_error_log,
e8bc2b5c
GS
1945 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
1946 ? " %5d"
1947 : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")),
827e134a 1948 buffer.nfree[i]);
8d063cd8 1949 }
e8bc2b5c 1950#endif
76cfd9aa 1951 PerlIO_printf(Perl_error_log, "\n%8ld used:", buffer.total - buffer.totfree);
827e134a 1952 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
bf49b057 1953 PerlIO_printf(Perl_error_log,
e8bc2b5c
GS
1954 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
1955 ? " %5d"
1956 : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")),
827e134a 1957 buffer.ntotal[i] - buffer.nfree[i]);
c07a80fd 1958 }
e8bc2b5c 1959#ifdef BUCKETS_ROOT2
bf49b057 1960 PerlIO_printf(Perl_error_log, "\n\t ");
827e134a 1961 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
bf49b057 1962 PerlIO_printf(Perl_error_log,
e8bc2b5c
GS
1963 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
1964 ? " %5d"
1965 : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")),
827e134a 1966 buffer.ntotal[i] - buffer.nfree[i]);
e8bc2b5c
GS
1967 }
1968#endif
76cfd9aa 1969 PerlIO_printf(Perl_error_log, "\nTotal sbrk(): %ld/%ld:%ld. Odd ends: pad+heads+chain+tail: %ld+%ld+%ld+%ld.\n",
827e134a
GS
1970 buffer.total_sbrk, buffer.sbrks, buffer.sbrk_good,
1971 buffer.sbrk_slack, buffer.start_slack,
1972 buffer.total_chain, buffer.sbrked_remains);
df31f264 1973#endif /* DEBUGGING_MSTATS */
c07a80fd 1974}
a687059c 1975#endif /* lint */
cf5c4ad8 1976
cf5c4ad8
PP
1977#ifdef USE_PERL_SBRK
1978
e3663bad 1979# if defined(__MACHTEN_PPC__) || defined(NeXT) || defined(__NeXT__) || defined(PURIFY)
38ac2dc8 1980# define PERL_SBRK_VIA_MALLOC
38ac2dc8
DD
1981# endif
1982
760ac839 1983# ifdef PERL_SBRK_VIA_MALLOC
cf5c4ad8
PP
1984
1985/* it may seem schizophrenic to use perl's malloc and let it call system */
1986/* malloc, the reason for that is only the 3.2 version of the OS that had */
1987/* frequent core dumps within nxzonefreenolock. This sbrk routine put an */
1988/* end to the cores */
1989
38ac2dc8
DD
1990# ifndef SYSTEM_ALLOC
1991# define SYSTEM_ALLOC(a) malloc(a)
1992# endif
5bbd1ef5
IZ
1993# ifndef SYSTEM_ALLOC_ALIGNMENT
1994# define SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES
1995# endif
cf5c4ad8 1996
760ac839 1997# endif /* PERL_SBRK_VIA_MALLOC */
cf5c4ad8
PP
1998
1999static IV Perl_sbrk_oldchunk;
2000static long Perl_sbrk_oldsize;
2001
760ac839
LW
2002# define PERLSBRK_32_K (1<<15)
2003# define PERLSBRK_64_K (1<<16)
cf5c4ad8 2004
b63effbb 2005Malloc_t
df0003d4 2006Perl_sbrk(int size)
cf5c4ad8
PP
2007{
2008 IV got;
2009 int small, reqsize;
2010
2011 if (!size) return 0;
55497cff 2012#ifdef PERL_CORE
cf5c4ad8
PP
2013 reqsize = size; /* just for the DEBUG_m statement */
2014#endif
57569e04
HM
2015#ifdef PACK_MALLOC
2016 size = (size + 0x7ff) & ~0x7ff;
2017#endif
cf5c4ad8
PP
2018 if (size <= Perl_sbrk_oldsize) {
2019 got = Perl_sbrk_oldchunk;
2020 Perl_sbrk_oldchunk += size;
2021 Perl_sbrk_oldsize -= size;
2022 } else {
2023 if (size >= PERLSBRK_32_K) {
2024 small = 0;
2025 } else {
cf5c4ad8
PP
2026 size = PERLSBRK_64_K;
2027 small = 1;
2028 }
5bbd1ef5
IZ
2029# if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2030 size += NEEDED_ALIGNMENT - SYSTEM_ALLOC_ALIGNMENT;
2031# endif
cf5c4ad8 2032 got = (IV)SYSTEM_ALLOC(size);
5bbd1ef5 2033# if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
5a7d6335 2034 got = (got + NEEDED_ALIGNMENT - 1) & ~(NEEDED_ALIGNMENT - 1);
5bbd1ef5 2035# endif
cf5c4ad8
PP
2036 if (small) {
2037 /* Chunk is small, register the rest for future allocs. */
2038 Perl_sbrk_oldchunk = got + reqsize;
2039 Perl_sbrk_oldsize = size - reqsize;
2040 }
2041 }
2042
b900a521
JH
2043 DEBUG_m(PerlIO_printf(Perl_debug_log, "sbrk malloc size %ld (reqsize %ld), left size %ld, give addr 0x%"UVxf"\n",
2044 size, reqsize, Perl_sbrk_oldsize, PTR2UV(got)));
cf5c4ad8
PP
2045
2046 return (void *)got;
2047}
2048
2049#endif /* ! defined USE_PERL_SBRK */