source: trunk/third/perl/malloc.c @ 20075

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1/*    malloc.c
2 *
3 */
4
5/*
6 * "'The Chamber of Records,' said Gimli. 'I guess that is where we now stand.'"
7 */
8
9/*
10  Here are some notes on configuring Perl's malloc.  (For non-perl
11  usage see below.)
12 
13  There are two macros which serve as bulk disablers of advanced
14  features of this malloc: NO_FANCY_MALLOC, PLAIN_MALLOC (undef by
15  default).  Look in the list of default values below to understand
16  their exact effect.  Defining NO_FANCY_MALLOC returns malloc.c to the
17  state of the malloc in Perl 5.004.  Additionally defining PLAIN_MALLOC
18  returns it to the state as of Perl 5.000.
19
20  Note that some of the settings below may be ignored in the code based
21  on values of other macros.  The PERL_CORE symbol is only defined when
22  perl itself is being compiled (so malloc can make some assumptions
23  about perl's facilities being available to it).
24
25  Each config option has a short description, followed by its name,
26  default value, and a comment about the default (if applicable).  Some
27  options take a precise value, while the others are just boolean.
28  The boolean ones are listed first.
29
30    # Read configuration settings from malloc_cfg.h
31    HAVE_MALLOC_CFG_H           undef
32
33    # Enable code for an emergency memory pool in $^M.  See perlvar.pod
34    # for a description of $^M.
35    PERL_EMERGENCY_SBRK         (!PLAIN_MALLOC && (PERL_CORE || !NO_MALLOC_DYNAMIC_CFG))
36
37    # Enable code for printing memory statistics.
38    DEBUGGING_MSTATS            (!PLAIN_MALLOC && PERL_CORE)
39
40    # Move allocation info for small buckets into separate areas.
41    # Memory optimization (especially for small allocations, of the
42    # less than 64 bytes).  Since perl usually makes a large number
43    # of small allocations, this is usually a win.
44    PACK_MALLOC                 (!PLAIN_MALLOC && !RCHECK)
45
46    # Add one page to big powers of two when calculating bucket size.
47    # This is targeted at big allocations, as are common in image
48    # processing.
49    TWO_POT_OPTIMIZE            !PLAIN_MALLOC
50 
51    # Use intermediate bucket sizes between powers-of-two.  This is
52    # generally a memory optimization, and a (small) speed pessimization.
53    BUCKETS_ROOT2               !NO_FANCY_MALLOC
54
55    # Do not check small deallocations for bad free().  Memory
56    # and speed optimization, error reporting pessimization.
57    IGNORE_SMALL_BAD_FREE       (!NO_FANCY_MALLOC && !RCHECK)
58
59    # Use table lookup to decide in which bucket a given allocation will go.
60    SMALL_BUCKET_VIA_TABLE      !NO_FANCY_MALLOC
61
62    # Use a perl-defined sbrk() instead of the (presumably broken or
63    # missing) system-supplied sbrk().
64    USE_PERL_SBRK               undef
65
66    # Use system malloc() (or calloc() etc.) to emulate sbrk(). Normally
67    # only used with broken sbrk()s.
68    PERL_SBRK_VIA_MALLOC        undef
69
70    # Which allocator to use if PERL_SBRK_VIA_MALLOC
71    SYSTEM_ALLOC(a)             malloc(a)
72
73    # Minimal alignment (in bytes, should be a power of 2) of SYSTEM_ALLOC
74    SYSTEM_ALLOC_ALIGNMENT      MEM_ALIGNBYTES
75
76    # Disable memory overwrite checking with DEBUGGING.  Memory and speed
77    # optimization, error reporting pessimization.
78    NO_RCHECK                   undef
79
80    # Enable memory overwrite checking with DEBUGGING.  Memory and speed
81    # pessimization, error reporting optimization
82    RCHECK                      (DEBUGGING && !NO_RCHECK)
83
84    # Do not overwrite uninit areas with DEBUGGING.  Speed
85    # optimization, error reporting pessimization
86    NO_MFILL                    undef
87
88    # Overwrite uninit areas with DEBUGGING.  Speed
89    # pessimization, error reporting optimization
90    MALLOC_FILL                 (DEBUGGING && !NO_RCHECK && !NO_MFILL)
91
92    # Do not check overwritten uninit areas with DEBUGGING.  Speed
93    # optimization, error reporting pessimization
94    NO_FILL_CHECK               undef
95
96    # Check overwritten uninit areas with DEBUGGING.  Speed
97    # pessimization, error reporting optimization
98    MALLOC_FILL_CHECK           (DEBUGGING && !NO_RCHECK && !NO_FILL_CHECK)
99
100    # Failed allocations bigger than this size croak (if
101    # PERL_EMERGENCY_SBRK is enabled) without touching $^M.  See
102    # perlvar.pod for a description of $^M.
103    BIG_SIZE                     (1<<16)        # 64K
104
105    # Starting from this power of two, add an extra page to the
106    # size of the bucket. This enables optimized allocations of sizes
107    # close to powers of 2.  Note that the value is indexed at 0.
108    FIRST_BIG_POW2              15              # 32K, 16K is used too often
109
110    # Estimate of minimal memory footprint.  malloc uses this value to
111    # request the most reasonable largest blocks of memory from the system.
112    FIRST_SBRK                  (48*1024)
113
114    # Round up sbrk()s to multiples of this.
115    MIN_SBRK                    2048
116
117    # Round up sbrk()s to multiples of this percent of footprint.
118    MIN_SBRK_FRAC               3
119
120    # Round up sbrk()s to multiples of this multiple of 1/1000 of footprint.
121    MIN_SBRK_FRAC1000           (10 * MIN_SBRK_FRAC)
122
123    # Add this much memory to big powers of two to get the bucket size.
124    PERL_PAGESIZE               4096
125
126    # This many sbrk() discontinuities should be tolerated even
127    # from the start without deciding that sbrk() is usually
128    # discontinuous.
129    SBRK_ALLOW_FAILURES         3
130
131    # This many continuous sbrk()s compensate for one discontinuous one.
132    SBRK_FAILURE_PRICE          50
133
134    # Some configurations may ask for 12-byte-or-so allocations which
135    # require 8-byte alignment (?!).  In such situation one needs to
136    # define this to disable 12-byte bucket (will increase memory footprint)
137    STRICT_ALIGNMENT            undef
138
139    # Do not allow configuration of runtime options at runtime
140    NO_MALLOC_DYNAMIC_CFG       undef
141
142    # Do not allow configuration of runtime options via $ENV{PERL_MALLOC_OPT}
143    NO_PERL_MALLOC_ENV          undef
144
145        [The variable consists of ;-separated parts of the form CODE=VALUE
146         with 1-character codes F, M, f, A, P, G, d, a, c for runtime
147         configuration of FIRST_SBRK, MIN_SBRK, MIN_SBRK_FRAC1000,
148         SBRK_ALLOW_FAILURES, SBRK_FAILURE_PRICE, sbrk_goodness,
149         filldead, fillalive, fillcheck.  The last 3 are for DEBUGGING
150         build, and allow switching the tests for free()ed memory read,
151         uninit memory reads, and free()ed memory write.]
152
153  This implementation assumes that calling PerlIO_printf() does not
154  result in any memory allocation calls (used during a panic).
155
156 */
157
158/*
159   If used outside of Perl environment, it may be useful to redefine
160   the following macros (listed below with defaults):
161
162     # Type of address returned by allocation functions
163     Malloc_t                           void *
164
165     # Type of size argument for allocation functions
166     MEM_SIZE                           unsigned long
167
168     # size of void*
169     PTRSIZE                            4
170
171     # Maximal value in LONG
172     LONG_MAX                           0x7FFFFFFF
173
174     # Unsigned integer type big enough to keep a pointer
175     UV                                 unsigned long
176
177     # Signed integer of the same sizeof() as UV
178     IV                                 long
179
180     # Type of pointer with 1-byte granularity
181     caddr_t                            char *
182
183     # Type returned by free()
184     Free_t                             void
185
186     # Conversion of pointer to integer
187     PTR2UV(ptr)                        ((UV)(ptr))
188
189     # Conversion of integer to pointer
190     INT2PTR(type, i)                   ((type)(i))
191
192     # printf()-%-Conversion of UV to pointer
193     UVuf                               "lu"
194
195     # printf()-%-Conversion of UV to hex pointer
196     UVxf                               "lx"
197
198     # Alignment to use
199     MEM_ALIGNBYTES                     4
200
201     # Very fatal condition reporting function (cannot call any )
202     fatalcroak(arg)                    write(2,arg,strlen(arg)) + exit(2)
203 
204     # Fatal error reporting function
205     croak(format, arg)                 warn(idem) + exit(1)
206 
207     # Fatal error reporting function
208     croak2(format, arg1, arg2)         warn2(idem) + exit(1)
209 
210     # Error reporting function
211     warn(format, arg)                  fprintf(stderr, idem)
212
213     # Error reporting function
214     warn2(format, arg1, arg2)          fprintf(stderr, idem)
215
216     # Locking/unlocking for MT operation
217     MALLOC_LOCK                        MUTEX_LOCK(&PL_malloc_mutex)
218     MALLOC_UNLOCK                      MUTEX_UNLOCK(&PL_malloc_mutex)
219
220     # Locking/unlocking mutex for MT operation
221     MUTEX_LOCK(l)                      void
222     MUTEX_UNLOCK(l)                    void
223 */
224
225#ifdef HAVE_MALLOC_CFG_H
226#  include "malloc_cfg.h"
227#endif
228
229#ifndef NO_FANCY_MALLOC
230#  ifndef SMALL_BUCKET_VIA_TABLE
231#    define SMALL_BUCKET_VIA_TABLE
232#  endif
233#  ifndef BUCKETS_ROOT2
234#    define BUCKETS_ROOT2
235#  endif
236#  ifndef IGNORE_SMALL_BAD_FREE
237#    define IGNORE_SMALL_BAD_FREE
238#  endif
239#endif
240
241#ifndef PLAIN_MALLOC                    /* Bulk enable features */
242#  ifndef PACK_MALLOC
243#      define PACK_MALLOC
244#  endif
245#  ifndef TWO_POT_OPTIMIZE
246#    define TWO_POT_OPTIMIZE
247#  endif
248#  if (defined(PERL_CORE) || !defined(NO_MALLOC_DYNAMIC_CFG)) && !defined(PERL_EMERGENCY_SBRK)
249#    define PERL_EMERGENCY_SBRK
250#  endif
251#  if defined(PERL_CORE) && !defined(DEBUGGING_MSTATS)
252#    define DEBUGGING_MSTATS
253#  endif
254#endif
255
256#define MIN_BUC_POW2 (sizeof(void*) > 4 ? 3 : 2) /* Allow for 4-byte arena. */
257#define MIN_BUCKET (MIN_BUC_POW2 * BUCKETS_PER_POW2)
258
259#if !(defined(I286) || defined(atarist) || defined(__MINT__))
260        /* take 2k unless the block is bigger than that */
261#  define LOG_OF_MIN_ARENA 11
262#else
263        /* take 16k unless the block is bigger than that
264           (80286s like large segments!), probably good on the atari too */
265#  define LOG_OF_MIN_ARENA 14
266#endif
267
268#ifndef lint
269#  if defined(DEBUGGING) && !defined(NO_RCHECK)
270#    define RCHECK
271#  endif
272#  if defined(DEBUGGING) && !defined(NO_RCHECK) && !defined(NO_MFILL) && !defined(MALLOC_FILL)
273#    define MALLOC_FILL
274#  endif
275#  if defined(DEBUGGING) && !defined(NO_RCHECK) && !defined(NO_FILL_CHECK) && !defined(MALLOC_FILL_CHECK)
276#    define MALLOC_FILL_CHECK
277#  endif
278#  if defined(RCHECK) && defined(IGNORE_SMALL_BAD_FREE)
279#    undef IGNORE_SMALL_BAD_FREE
280#  endif
281/*
282 * malloc.c (Caltech) 2/21/82
283 * Chris Kingsley, kingsley@cit-20.
284 *
285 * This is a very fast storage allocator.  It allocates blocks of a small
286 * number of different sizes, and keeps free lists of each size.  Blocks that
287 * don't exactly fit are passed up to the next larger size.  In this
288 * implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long.
289 * If PACK_MALLOC is defined, small blocks are 2^n bytes long.
290 * This is designed for use in a program that uses vast quantities of memory,
291 * but bombs when it runs out.
292 *
293 * Modifications Copyright Ilya Zakharevich 1996-99.
294 *
295 * Still very quick, but much more thrifty.  (Std config is 10% slower
296 * than it was, and takes 67% of old heap size for typical usage.)
297 *
298 * Allocations of small blocks are now table-driven to many different
299 * buckets.  Sizes of really big buckets are increased to accomodata
300 * common size=power-of-2 blocks.  Running-out-of-memory is made into
301 * an exception.  Deeply configurable and thread-safe.
302 *
303 */
304
305#ifdef PERL_CORE
306#  include "EXTERN.h"
307#  define PERL_IN_MALLOC_C
308#  include "perl.h"
309#  if defined(PERL_IMPLICIT_CONTEXT)
310#    define croak       Perl_croak_nocontext
311#    define croak2      Perl_croak_nocontext
312#    define warn        Perl_warn_nocontext
313#    define warn2       Perl_warn_nocontext
314#  else
315#    define croak2      croak
316#    define warn2       warn
317#  endif
318#  if defined(USE_5005THREADS) || defined(USE_ITHREADS)
319#     define PERL_MAYBE_ALIVE   PL_thr_key
320#  else
321#     define PERL_MAYBE_ALIVE   1
322#  endif
323#else
324#  ifdef PERL_FOR_X2P
325#    include "../EXTERN.h"
326#    include "../perl.h"
327#  else
328#    include <stdlib.h>
329#    include <stdio.h>
330#    include <memory.h>
331#    ifdef OS2
332#      include <io.h>
333#    endif
334#    include <string.h>
335#    ifndef Malloc_t
336#      define Malloc_t void *
337#    endif
338#    ifndef PTRSIZE
339#      define PTRSIZE 4
340#    endif
341#    ifndef MEM_SIZE
342#      define MEM_SIZE unsigned long
343#    endif
344#    ifndef LONG_MAX
345#      define LONG_MAX 0x7FFFFFFF
346#    endif
347#    ifndef UV
348#      define UV unsigned long
349#    endif
350#    ifndef IV
351#      define IV long
352#    endif
353#    ifndef caddr_t
354#      define caddr_t char *
355#    endif
356#    ifndef Free_t
357#      define Free_t void
358#    endif
359#    define Copy(s,d,n,t) (void)memcpy((char*)(d),(char*)(s), (n) * sizeof(t))
360#    define PerlEnv_getenv getenv
361#    define PerlIO_printf fprintf
362#    define PerlIO_stderr() stderr
363#    define PerlIO_puts(f,s)            fputs(s,f)
364#    ifndef INT2PTR
365#      define INT2PTR(t,i)              ((t)(i))
366#    endif
367#    ifndef PTR2UV
368#      define PTR2UV(p)                 ((UV)(p))
369#    endif
370#    ifndef UVuf
371#      define UVuf                      "lu"
372#    endif
373#    ifndef UVxf
374#      define UVxf                      "lx"
375#    endif
376#    ifndef Nullch
377#      define Nullch                    NULL
378#    endif
379#    ifndef MEM_ALIGNBYTES
380#      define MEM_ALIGNBYTES            4
381#    endif
382#  endif
383#  ifndef croak                         /* make depend */
384#    define croak(mess, arg) (warn((mess), (arg)), exit(1))
385#  endif
386#  ifndef croak2                        /* make depend */
387#    define croak2(mess, arg1, arg2) (warn2((mess), (arg1), (arg2)), exit(1))
388#  endif
389#  ifndef warn
390#    define warn(mess, arg) fprintf(stderr, (mess), (arg))
391#  endif
392#  ifndef warn2
393#    define warn2(mess, arg1, arg2) fprintf(stderr, (mess), (arg1), (arg2))
394#  endif
395#  ifdef DEBUG_m
396#    undef DEBUG_m
397#  endif
398#  define DEBUG_m(a)
399#  ifdef DEBUGGING
400#     undef DEBUGGING
401#  endif
402#  ifndef pTHX
403#     define pTHX               void
404#     define pTHX_
405#     ifdef HASATTRIBUTE
406#        define dTHX            extern int Perl___notused PERL_UNUSED_DECL
407#     else
408#        define dTHX            extern int Perl___notused
409#     endif
410#     define WITH_THX(s)        s
411#  endif
412#  ifndef PERL_GET_INTERP
413#     define PERL_GET_INTERP    PL_curinterp
414#  endif
415#  define PERL_MAYBE_ALIVE      1
416#  ifndef Perl_malloc
417#     define Perl_malloc malloc
418#  endif
419#  ifndef Perl_mfree
420#     define Perl_mfree free
421#  endif
422#  ifndef Perl_realloc
423#     define Perl_realloc realloc
424#  endif
425#  ifndef Perl_calloc
426#     define Perl_calloc calloc
427#  endif
428#  ifndef Perl_strdup
429#     define Perl_strdup strdup
430#  endif
431#endif  /* defined PERL_CORE */
432
433#ifndef MUTEX_LOCK
434#  define MUTEX_LOCK(l)
435#endif
436
437#ifndef MUTEX_UNLOCK
438#  define MUTEX_UNLOCK(l)
439#endif
440
441#ifndef MALLOC_LOCK
442#  define MALLOC_LOCK           MUTEX_LOCK(&PL_malloc_mutex)
443#endif
444
445#ifndef MALLOC_UNLOCK
446#  define MALLOC_UNLOCK         MUTEX_UNLOCK(&PL_malloc_mutex)
447#endif
448
449#  ifndef fatalcroak                            /* make depend */
450#    define fatalcroak(mess)    (write(2, (mess), strlen(mess)), exit(2))
451#  endif
452
453#ifdef DEBUGGING
454#  undef DEBUG_m
455#  define DEBUG_m(a)                                                    \
456    STMT_START {                                                        \
457        if (PERL_MAYBE_ALIVE && PERL_GET_THX) {                                         \
458            dTHX;                                                       \
459            if (DEBUG_m_TEST) {                                         \
460                PL_debug &= ~DEBUG_m_FLAG;                              \
461                a;                                                      \
462                PL_debug |= DEBUG_m_FLAG;                               \
463            }                                                           \
464        }                                                               \
465    } STMT_END
466#endif
467
468#ifdef PERL_IMPLICIT_CONTEXT
469#  define PERL_IS_ALIVE         aTHX
470#else
471#  define PERL_IS_ALIVE         TRUE
472#endif
473   
474
475/*
476 * Layout of memory:
477 * ~~~~~~~~~~~~~~~~
478 * The memory is broken into "blocks" which occupy multiples of 2K (and
479 * generally speaking, have size "close" to a power of 2).  The addresses
480 * of such *unused* blocks are kept in nextf[i] with big enough i.  (nextf
481 * is an array of linked lists.)  (Addresses of used blocks are not known.)
482 *
483 * Moreover, since the algorithm may try to "bite" smaller blocks out
484 * of unused bigger ones, there are also regions of "irregular" size,
485 * managed separately, by a linked list chunk_chain.
486 *
487 * The third type of storage is the sbrk()ed-but-not-yet-used space, its
488 * end and size are kept in last_sbrk_top and sbrked_remains.
489 *
490 * Growing blocks "in place":
491 * ~~~~~~~~~~~~~~~~~~~~~~~~~
492 * The address of the block with the greatest address is kept in last_op
493 * (if not known, last_op is 0).  If it is known that the memory above
494 * last_op is not continuous, or contains a chunk from chunk_chain,
495 * last_op is set to 0.
496 *
497 * The chunk with address last_op may be grown by expanding into
498 * sbrk()ed-but-not-yet-used space, or trying to sbrk() more continuous
499 * memory.
500 *
501 * Management of last_op:
502 * ~~~~~~~~~~~~~~~~~~~~~
503 *
504 * free() never changes the boundaries of blocks, so is not relevant.
505 *
506 * The only way realloc() may change the boundaries of blocks is if it
507 * grows a block "in place".  However, in the case of success such a
508 * chunk is automatically last_op, and it remains last_op.  In the case
509 * of failure getpages_adjacent() clears last_op.
510 *
511 * malloc() may change blocks by calling morecore() only.
512 *
513 * morecore() may create new blocks by:
514 *   a) biting pieces from chunk_chain (cannot create one above last_op);
515 *   b) biting a piece from an unused block (if block was last_op, this
516 *      may create a chunk from chain above last_op, thus last_op is
517 *      invalidated in such a case).
518 *   c) biting of sbrk()ed-but-not-yet-used space.  This creates
519 *      a block which is last_op.
520 *   d) Allocating new pages by calling getpages();
521 *
522 * getpages() creates a new block.  It marks last_op at the bottom of
523 * the chunk of memory it returns.
524 *
525 * Active pages footprint:
526 * ~~~~~~~~~~~~~~~~~~~~~~
527 * Note that we do not need to traverse the lists in nextf[i], just take
528 * the first element of this list.  However, we *need* to traverse the
529 * list in chunk_chain, but most the time it should be a very short one,
530 * so we do not step on a lot of pages we are not going to use.
531 *
532 * Flaws:
533 * ~~~~~
534 * get_from_bigger_buckets(): forget to increment price => Quite
535 * aggressive.
536 */
537
538/* I don't much care whether these are defined in sys/types.h--LAW */
539
540#define u_char unsigned char
541#define u_int unsigned int
542/*
543 * I removed the definition of u_bigint which appeared to be u_bigint = UV
544 * u_bigint was only used in TWOK_MASKED and TWOK_SHIFT
545 * where I have used PTR2UV.  RMB
546 */
547#define u_short unsigned short
548
549/* 286 and atarist like big chunks, which gives too much overhead. */
550#if (defined(RCHECK) || defined(I286) || defined(atarist) || defined(__MINT__)) && defined(PACK_MALLOC)
551#  undef PACK_MALLOC
552#endif
553
554/*
555 * The description below is applicable if PACK_MALLOC is not defined.
556 *
557 * The overhead on a block is at least 4 bytes.  When free, this space
558 * contains a pointer to the next free block, and the bottom two bits must
559 * be zero.  When in use, the first byte is set to MAGIC, and the second
560 * byte is the size index.  The remaining bytes are for alignment.
561 * If range checking is enabled and the size of the block fits
562 * in two bytes, then the top two bytes hold the size of the requested block
563 * plus the range checking words, and the header word MINUS ONE.
564 */
565union   overhead {
566        union   overhead *ov_next;      /* when free */
567#if MEM_ALIGNBYTES > 4
568        double  strut;                  /* alignment problems */
569#  if MEM_ALIGNBYTES > 8
570        char    sstrut[MEM_ALIGNBYTES]; /* for the sizing */
571#  endif
572#endif
573        struct {
574/*
575 * Keep the ovu_index and ovu_magic in this order, having a char
576 * field first gives alignment indigestion in some systems, such as
577 * MachTen.
578 */
579                u_char  ovu_index;      /* bucket # */
580                u_char  ovu_magic;      /* magic number */
581#ifdef RCHECK
582            /* Subtract one to fit into u_short for an extra bucket */
583                u_short ovu_size;       /* block size (requested + overhead - 1) */
584                u_int   ovu_rmagic;     /* range magic number */
585#endif
586        } ovu;
587#define ov_magic        ovu.ovu_magic
588#define ov_index        ovu.ovu_index
589#define ov_size         ovu.ovu_size
590#define ov_rmagic       ovu.ovu_rmagic
591};
592
593#define MAGIC           0xff            /* magic # on accounting info */
594#define RMAGIC          0x55555555      /* magic # on range info */
595#define RMAGIC_C        0x55            /* magic # on range info */
596
597#ifdef RCHECK
598#  define       RMAGIC_SZ       sizeof (u_int) /* Overhead at end of bucket */
599#  ifdef TWO_POT_OPTIMIZE
600#    define MAX_SHORT_BUCKET (12 * BUCKETS_PER_POW2) /* size-1 fits in short */
601#  else
602#    define MAX_SHORT_BUCKET (13 * BUCKETS_PER_POW2)
603#  endif
604#else
605#  define       RMAGIC_SZ       0
606#endif
607
608#if !defined(PACK_MALLOC) && defined(BUCKETS_ROOT2)
609#  undef BUCKETS_ROOT2
610#endif
611
612#ifdef BUCKETS_ROOT2
613#  define BUCKET_TABLE_SHIFT 2
614#  define BUCKET_POW2_SHIFT 1
615#  define BUCKETS_PER_POW2 2
616#else
617#  define BUCKET_TABLE_SHIFT MIN_BUC_POW2
618#  define BUCKET_POW2_SHIFT 0
619#  define BUCKETS_PER_POW2 1
620#endif
621
622#if !defined(MEM_ALIGNBYTES) || ((MEM_ALIGNBYTES > 4) && !defined(STRICT_ALIGNMENT))
623/* Figure out the alignment of void*. */
624struct aligner {
625  char c;
626  void *p;
627};
628#  define ALIGN_SMALL ((int)((caddr_t)&(((struct aligner*)0)->p)))
629#else
630#  define ALIGN_SMALL MEM_ALIGNBYTES
631#endif
632
633#define IF_ALIGN_8(yes,no)      ((ALIGN_SMALL>4) ? (yes) : (no))
634
635#ifdef BUCKETS_ROOT2
636#  define MAX_BUCKET_BY_TABLE 13
637static u_short buck_size[MAX_BUCKET_BY_TABLE + 1] =
638  {
639      0, 0, 0, 0, 4, 4, 8, 12, 16, 24, 32, 48, 64, 80,
640  };
641#  define BUCKET_SIZE_NO_SURPLUS(i) ((i) % 2 ? buck_size[i] : (1 << ((i) >> BUCKET_POW2_SHIFT)))
642#  define BUCKET_SIZE_REAL(i) ((i) <= MAX_BUCKET_BY_TABLE               \
643                               ? buck_size[i]                           \
644                               : ((1 << ((i) >> BUCKET_POW2_SHIFT))     \
645                                  - MEM_OVERHEAD(i)                     \
646                                  + POW2_OPTIMIZE_SURPLUS(i)))
647#else
648#  define BUCKET_SIZE_NO_SURPLUS(i) (1 << ((i) >> BUCKET_POW2_SHIFT))
649#  define BUCKET_SIZE(i) (BUCKET_SIZE_NO_SURPLUS(i) + POW2_OPTIMIZE_SURPLUS(i))
650#  define BUCKET_SIZE_REAL(i) (BUCKET_SIZE(i) - MEM_OVERHEAD(i))
651#endif
652
653
654#ifdef PACK_MALLOC
655/* In this case there are several possible layout of arenas depending
656 * on the size.  Arenas are of sizes multiple to 2K, 2K-aligned, and
657 * have a size close to a power of 2.
658 *
659 * Arenas of the size >= 4K keep one chunk only.  Arenas of size 2K
660 * may keep one chunk or multiple chunks.  Here are the possible
661 * layouts of arenas:
662 *
663 *      # One chunk only, chunksize 2^k + SOMETHING - ALIGN, k >= 11
664 *
665 * INDEX MAGIC1 UNUSED CHUNK1
666 *
667 *      # Multichunk with sanity checking and chunksize 2^k-ALIGN, k>7
668 *
669 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 CHUNK2 CHUNK3 ...
670 *
671 *      # Multichunk with sanity checking and size 2^k-ALIGN, k=7
672 *
673 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 UNUSED CHUNK2 CHUNK3 ...
674 *
675 *      # Multichunk with sanity checking and size up to 80
676 *
677 * INDEX UNUSED MAGIC1 UNUSED MAGIC2 UNUSED ... CHUNK1 CHUNK2 CHUNK3 ...
678 *
679 *      # No sanity check (usually up to 48=byte-long buckets)
680 * INDEX UNUSED CHUNK1 CHUNK2 ...
681 *
682 * Above INDEX and MAGIC are one-byte-long.  Sizes of UNUSED are
683 * appropriate to keep algorithms simple and memory aligned.  INDEX
684 * encodes the size of the chunk, while MAGICn encodes state (used,
685 * free or non-managed-by-us-so-it-indicates-a-bug) of CHUNKn.  MAGIC
686 * is used for sanity checking purposes only.  SOMETHING is 0 or 4K
687 * (to make size of big CHUNK accomodate allocations for powers of two
688 * better).
689 *
690 * [There is no need to alignment between chunks, since C rules ensure
691 *  that structs which need 2^k alignment have sizeof which is
692 *  divisible by 2^k.  Thus as far as the last chunk is aligned at the
693 *  end of the arena, and 2K-alignment does not contradict things,
694 *  everything is going to be OK for sizes of chunks 2^n and 2^n +
695 *  2^k.  Say, 80-bit buckets will be 16-bit aligned, and as far as we
696 *  put allocations for requests in 65..80 range, all is fine.
697 *
698 *  Note, however, that standard malloc() puts more strict
699 *  requirements than the above C rules.  Moreover, our algorithms of
700 *  realloc() may break this idyll, but we suppose that realloc() does
701 *  need not change alignment.]
702 *
703 * Is very important to make calculation of the offset of MAGICm as
704 * quick as possible, since it is done on each malloc()/free().  In
705 * fact it is so quick that it has quite little effect on the speed of
706 * doing malloc()/free().  [By default] We forego such calculations
707 * for small chunks, but only to save extra 3% of memory, not because
708 * of speed considerations.
709 *
710 * Here is the algorithm [which is the same for all the allocations
711 * schemes above], see OV_MAGIC(block,bucket).  Let OFFSETm be the
712 * offset of the CHUNKm from the start of ARENA.  Then offset of
713 * MAGICm is (OFFSET1 >> SHIFT) + ADDOFFSET.  Here SHIFT and ADDOFFSET
714 * are numbers which depend on the size of the chunks only.
715 *
716 * Let as check some sanity conditions.  Numbers OFFSETm>>SHIFT are
717 * different for all the chunks in the arena if 2^SHIFT is not greater
718 * than size of the chunks in the arena.  MAGIC1 will not overwrite
719 * INDEX provided ADDOFFSET is >0 if OFFSET1 < 2^SHIFT.  MAGIClast
720 * will not overwrite CHUNK1 if OFFSET1 > (OFFSETlast >> SHIFT) +
721 * ADDOFFSET.
722 *
723 * Make SHIFT the maximal possible (there is no point in making it
724 * smaller).  Since OFFSETlast is 2K - CHUNKSIZE, above restrictions
725 * give restrictions on OFFSET1 and on ADDOFFSET.
726 *
727 * In particular, for chunks of size 2^k with k>=6 we can put
728 * ADDOFFSET to be from 0 to 2^k - 2^(11-k), and have
729 * OFFSET1==chunksize.  For chunks of size 80 OFFSET1 of 2K%80=48 is
730 * large enough to have ADDOFFSET between 1 and 16 (similarly for 96,
731 * when ADDOFFSET should be 1).  In particular, keeping MAGICs for
732 * these sizes gives no additional size penalty.
733 *
734 * However, for chunks of size 2^k with k<=5 this gives OFFSET1 >=
735 * ADDOFSET + 2^(11-k).  Keeping ADDOFFSET 0 allows for 2^(11-k)-2^(11-2k)
736 * chunks per arena.  This is smaller than 2^(11-k) - 1 which are
737 * needed if no MAGIC is kept.  [In fact, having a negative ADDOFFSET
738 * would allow for slightly more buckets per arena for k=2,3.]
739 *
740 * Similarly, for chunks of size 3/2*2^k with k<=5 MAGICs would span
741 * the area up to 2^(11-k)+ADDOFFSET.  For k=4 this give optimal
742 * ADDOFFSET as -7..0.  For k=3 ADDOFFSET can go up to 4 (with tiny
743 * savings for negative ADDOFFSET).  For k=5 ADDOFFSET can go -1..16
744 * (with no savings for negative values).
745 *
746 * In particular, keeping ADDOFFSET 0 for sizes of chunks up to 2^6
747 * leads to tiny pessimizations in case of sizes 4, 8, 12, 24, and
748 * leads to no contradictions except for size=80 (or 96.)
749 *
750 * However, it also makes sense to keep no magic for sizes 48 or less.
751 * This is what we do.  In this case one needs ADDOFFSET>=1 also for
752 * chunksizes 12, 24, and 48, unless one gets one less chunk per
753 * arena.
754 * 
755 * The algo of OV_MAGIC(block,bucket) keeps ADDOFFSET 0 until
756 * chunksize of 64, then makes it 1.
757 *
758 * This allows for an additional optimization: the above scheme leads
759 * to giant overheads for sizes 128 or more (one whole chunk needs to
760 * be sacrifised to keep INDEX).  Instead we use chunks not of size
761 * 2^k, but of size 2^k-ALIGN.  If we pack these chunks at the end of
762 * the arena, then the beginnings are still in different 2^k-long
763 * sections of the arena if k>=7 for ALIGN==4, and k>=8 if ALIGN=8.
764 * Thus for k>7 the above algo of calculating the offset of the magic
765 * will still give different answers for different chunks.  And to
766 * avoid the overrun of MAGIC1 into INDEX, one needs ADDOFFSET of >=1.
767 * In the case k=7 we just move the first chunk an extra ALIGN
768 * backward inside the ARENA (this is done once per arena lifetime,
769 * thus is not a big overhead).  */
770#  define MAX_PACKED_POW2 6
771#  define MAX_PACKED (MAX_PACKED_POW2 * BUCKETS_PER_POW2 + BUCKET_POW2_SHIFT)
772#  define MAX_POW2_ALGO ((1<<(MAX_PACKED_POW2 + 1)) - M_OVERHEAD)
773#  define TWOK_MASK ((1<<LOG_OF_MIN_ARENA) - 1)
774#  define TWOK_MASKED(x) (PTR2UV(x) & ~TWOK_MASK)
775#  define TWOK_SHIFT(x) (PTR2UV(x) & TWOK_MASK)
776#  define OV_INDEXp(block) (INT2PTR(u_char*,TWOK_MASKED(block)))
777#  define OV_INDEX(block) (*OV_INDEXp(block))
778#  define OV_MAGIC(block,bucket) (*(OV_INDEXp(block) +                  \
779                                    (TWOK_SHIFT(block)>>                \
780                                     (bucket>>BUCKET_POW2_SHIFT)) +     \
781                                    (bucket >= MIN_NEEDS_SHIFT ? 1 : 0)))
782    /* A bucket can have a shift smaller than it size, we need to
783       shift its magic number so it will not overwrite index: */
784#  ifdef BUCKETS_ROOT2
785#    define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2 - 1) /* Shift 80 greater than chunk 64. */
786#  else
787#    define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2) /* Shift 128 greater than chunk 32. */
788#  endif
789#  define CHUNK_SHIFT 0
790
791/* Number of active buckets of given ordinal. */
792#ifdef IGNORE_SMALL_BAD_FREE
793#define FIRST_BUCKET_WITH_CHECK (6 * BUCKETS_PER_POW2) /* 64 */
794#  define N_BLKS(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK           \
795                         ? ((1<<LOG_OF_MIN_ARENA) - 1)/BUCKET_SIZE_NO_SURPLUS(bucket) \
796                         : n_blks[bucket] )
797#else
798#  define N_BLKS(bucket) n_blks[bucket]
799#endif
800
801static u_short n_blks[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
802  {
803#  if BUCKETS_PER_POW2==1
804      0, 0,
805      (MIN_BUC_POW2==2 ? 384 : 0),
806      224, 120, 62, 31, 16, 8, 4, 2
807#  else
808      0, 0, 0, 0,
809      (MIN_BUC_POW2==2 ? 384 : 0), (MIN_BUC_POW2==2 ? 384 : 0), /* 4, 4 */
810      224, 149, 120, 80, 62, 41, 31, 25, 16, 16, 8, 8, 4, 4, 2, 2
811#  endif
812  };
813
814/* Shift of the first bucket with the given ordinal inside 2K chunk. */
815#ifdef IGNORE_SMALL_BAD_FREE
816#  define BLK_SHIFT(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK        \
817                              ? ((1<<LOG_OF_MIN_ARENA)                  \
818                                 - BUCKET_SIZE_NO_SURPLUS(bucket) * N_BLKS(bucket)) \
819                              : blk_shift[bucket])
820#else
821#  define BLK_SHIFT(bucket) blk_shift[bucket]
822#endif
823
824static u_short blk_shift[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
825  {
826#  if BUCKETS_PER_POW2==1
827      0, 0,
828      (MIN_BUC_POW2==2 ? 512 : 0),
829      256, 128, 64, 64,                 /* 8 to 64 */
830      16*sizeof(union overhead),
831      8*sizeof(union overhead),
832      4*sizeof(union overhead),
833      2*sizeof(union overhead),
834#  else
835      0, 0, 0, 0,
836      (MIN_BUC_POW2==2 ? 512 : 0), (MIN_BUC_POW2==2 ? 512 : 0),
837      256, 260, 128, 128, 64, 80, 64, 48, /* 8 to 96 */
838      16*sizeof(union overhead), 16*sizeof(union overhead),
839      8*sizeof(union overhead), 8*sizeof(union overhead),
840      4*sizeof(union overhead), 4*sizeof(union overhead),
841      2*sizeof(union overhead), 2*sizeof(union overhead),
842#  endif
843  };
844
845#  define NEEDED_ALIGNMENT 0x800        /* 2k boundaries */
846#  define WANTED_ALIGNMENT 0x800        /* 2k boundaries */
847
848#else  /* !PACK_MALLOC */
849
850#  define OV_MAGIC(block,bucket) (block)->ov_magic
851#  define OV_INDEX(block) (block)->ov_index
852#  define CHUNK_SHIFT 1
853#  define MAX_PACKED -1
854#  define NEEDED_ALIGNMENT MEM_ALIGNBYTES
855#  define WANTED_ALIGNMENT 0x400        /* 1k boundaries */
856
857#endif /* !PACK_MALLOC */
858
859#define M_OVERHEAD (sizeof(union overhead) + RMAGIC_SZ) /* overhead at start+end */
860
861#ifdef PACK_MALLOC
862#  define MEM_OVERHEAD(bucket) \
863  (bucket <= MAX_PACKED ? 0 : M_OVERHEAD)
864#  ifdef SMALL_BUCKET_VIA_TABLE
865#    define START_SHIFTS_BUCKET ((MAX_PACKED_POW2 + 1) * BUCKETS_PER_POW2)
866#    define START_SHIFT MAX_PACKED_POW2
867#    ifdef BUCKETS_ROOT2                /* Chunks of size 3*2^n. */
868#      define SIZE_TABLE_MAX 80
869#    else
870#      define SIZE_TABLE_MAX 64
871#    endif
872static char bucket_of[] =
873  {
874#    ifdef BUCKETS_ROOT2                /* Chunks of size 3*2^n. */
875      /* 0 to 15 in 4-byte increments. */
876      (sizeof(void*) > 4 ? 6 : 5),      /* 4/8, 5-th bucket for better reports */
877      6,                                /* 8 */
878      IF_ALIGN_8(8,7), 8,               /* 16/12, 16 */
879      9, 9, 10, 10,                     /* 24, 32 */
880      11, 11, 11, 11,                   /* 48 */
881      12, 12, 12, 12,                   /* 64 */
882      13, 13, 13, 13,                   /* 80 */
883      13, 13, 13, 13                    /* 80 */
884#    else /* !BUCKETS_ROOT2 */
885      /* 0 to 15 in 4-byte increments. */
886      (sizeof(void*) > 4 ? 3 : 2),
887      3,
888      4, 4,
889      5, 5, 5, 5,
890      6, 6, 6, 6,
891      6, 6, 6, 6
892#    endif /* !BUCKETS_ROOT2 */
893  };
894#  else  /* !SMALL_BUCKET_VIA_TABLE */
895#    define START_SHIFTS_BUCKET MIN_BUCKET
896#    define START_SHIFT (MIN_BUC_POW2 - 1)
897#  endif /* !SMALL_BUCKET_VIA_TABLE */
898#else  /* !PACK_MALLOC */
899#  define MEM_OVERHEAD(bucket) M_OVERHEAD
900#  ifdef SMALL_BUCKET_VIA_TABLE
901#    undef SMALL_BUCKET_VIA_TABLE
902#  endif
903#  define START_SHIFTS_BUCKET MIN_BUCKET
904#  define START_SHIFT (MIN_BUC_POW2 - 1)
905#endif /* !PACK_MALLOC */
906
907/*
908 * Big allocations are often of the size 2^n bytes. To make them a
909 * little bit better, make blocks of size 2^n+pagesize for big n.
910 */
911
912#ifdef TWO_POT_OPTIMIZE
913
914#  ifndef PERL_PAGESIZE
915#    define PERL_PAGESIZE 4096
916#  endif
917#  ifndef FIRST_BIG_POW2
918#    define FIRST_BIG_POW2 15   /* 32K, 16K is used too often. */
919#  endif
920#  define FIRST_BIG_BLOCK (1<<FIRST_BIG_POW2)
921/* If this value or more, check against bigger blocks. */
922#  define FIRST_BIG_BOUND (FIRST_BIG_BLOCK - M_OVERHEAD)
923/* If less than this value, goes into 2^n-overhead-block. */
924#  define LAST_SMALL_BOUND ((FIRST_BIG_BLOCK>>1) - M_OVERHEAD)
925
926#  define POW2_OPTIMIZE_ADJUST(nbytes)                          \
927   ((nbytes >= FIRST_BIG_BOUND) ? nbytes -= PERL_PAGESIZE : 0)
928#  define POW2_OPTIMIZE_SURPLUS(bucket)                         \
929   ((bucket >= FIRST_BIG_POW2 * BUCKETS_PER_POW2) ? PERL_PAGESIZE : 0)
930
931#else  /* !TWO_POT_OPTIMIZE */
932#  define POW2_OPTIMIZE_ADJUST(nbytes)
933#  define POW2_OPTIMIZE_SURPLUS(bucket) 0
934#endif /* !TWO_POT_OPTIMIZE */
935
936#if defined(HAS_64K_LIMIT) && defined(PERL_CORE)
937#  define BARK_64K_LIMIT(what,nbytes,size)                              \
938        if (nbytes > 0xffff) {                                          \
939                PerlIO_printf(PerlIO_stderr(),                          \
940                              "%s too large: %lx\n", what, size);       \
941                my_exit(1);                                             \
942        }
943#else /* !HAS_64K_LIMIT || !PERL_CORE */
944#  define BARK_64K_LIMIT(what,nbytes,size)
945#endif /* !HAS_64K_LIMIT || !PERL_CORE */
946
947#ifndef MIN_SBRK
948#  define MIN_SBRK 2048
949#endif
950
951#ifndef FIRST_SBRK
952#  define FIRST_SBRK (48*1024)
953#endif
954
955/* Minimal sbrk in percents of what is already alloced. */
956#ifndef MIN_SBRK_FRAC
957#  define MIN_SBRK_FRAC 3
958#endif
959
960#ifndef SBRK_ALLOW_FAILURES
961#  define SBRK_ALLOW_FAILURES 3
962#endif
963
964#ifndef SBRK_FAILURE_PRICE
965#  define SBRK_FAILURE_PRICE 50
966#endif
967
968static void     morecore        (register int bucket);
969#  if defined(DEBUGGING)
970static void     botch           (char *diag, char *s, char *file, int line);
971#  endif
972static void     add_to_chain    (void *p, MEM_SIZE size, MEM_SIZE chip);
973static void*    get_from_chain  (MEM_SIZE size);
974static void*    get_from_bigger_buckets(int bucket, MEM_SIZE size);
975static union overhead *getpages (MEM_SIZE needed, int *nblksp, int bucket);
976static int      getpages_adjacent(MEM_SIZE require);
977
978#ifdef PERL_CORE
979
980#ifdef I_MACH_CTHREADS
981#  undef  MUTEX_LOCK
982#  define MUTEX_LOCK(m)   STMT_START { if (*m) mutex_lock(*m);   } STMT_END
983#  undef  MUTEX_UNLOCK
984#  define MUTEX_UNLOCK(m) STMT_START { if (*m) mutex_unlock(*m); } STMT_END
985#endif
986
987#endif  /* defined PERL_CORE */
988
989#ifndef PTRSIZE
990#  define PTRSIZE       sizeof(void*)
991#endif
992
993#ifndef BITS_IN_PTR
994#  define BITS_IN_PTR (8*PTRSIZE)
995#endif
996
997/*
998 * nextf[i] is the pointer to the next free block of size 2^i.  The
999 * smallest allocatable block is 8 bytes.  The overhead information
1000 * precedes the data area returned to the user.
1001 */
1002#define NBUCKETS (BITS_IN_PTR*BUCKETS_PER_POW2 + 1)
1003static  union overhead *nextf[NBUCKETS];
1004
1005#if defined(PURIFY) && !defined(USE_PERL_SBRK)
1006#  define USE_PERL_SBRK
1007#endif
1008
1009#ifdef USE_PERL_SBRK
1010# define sbrk(a) Perl_sbrk(a)
1011Malloc_t Perl_sbrk (int size);
1012#else
1013# ifndef HAS_SBRK_PROTO /* <unistd.h> usually takes care of this */
1014extern  Malloc_t sbrk(int);
1015# endif
1016#endif
1017
1018#ifndef MIN_SBRK_FRAC1000       /* Backward compatibility */
1019#  define MIN_SBRK_FRAC1000     (MIN_SBRK_FRAC * 10)
1020#endif
1021
1022#ifndef START_EXTERN_C
1023#  ifdef __cplusplus
1024#    define START_EXTERN_C      extern "C" {
1025#  else
1026#    define START_EXTERN_C
1027#  endif
1028#endif
1029
1030#ifndef END_EXTERN_C
1031#  ifdef __cplusplus
1032#    define END_EXTERN_C                };
1033#  else
1034#    define END_EXTERN_C
1035#  endif
1036#endif
1037
1038#include "malloc_ctl.h"
1039
1040#ifndef NO_MALLOC_DYNAMIC_CFG
1041#  define PERL_MALLOC_OPT_CHARS "FMfAPGdac"
1042
1043#  ifndef FILL_DEAD_DEFAULT
1044#    define FILL_DEAD_DEFAULT   1
1045#  endif
1046#  ifndef FILL_ALIVE_DEFAULT
1047#    define FILL_ALIVE_DEFAULT  1
1048#  endif
1049#  ifndef FILL_CHECK_DEFAULT
1050#    define FILL_CHECK_DEFAULT  1
1051#  endif
1052
1053static IV MallocCfg[MallocCfg_last] = {
1054  FIRST_SBRK,
1055  MIN_SBRK,
1056  MIN_SBRK_FRAC,
1057  SBRK_ALLOW_FAILURES,
1058  SBRK_FAILURE_PRICE,
1059  SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE,     /* sbrk_goodness */
1060  FILL_DEAD_DEFAULT,    /* FILL_DEAD */
1061  FILL_ALIVE_DEFAULT,   /* FILL_ALIVE */
1062  FILL_CHECK_DEFAULT,   /* FILL_CHECK */
1063  0,                    /* MallocCfg_skip_cfg_env */
1064  0,                    /* MallocCfg_cfg_env_read */
1065  0,                    /* MallocCfg_emergency_buffer_size */
1066  0,                    /* MallocCfg_emergency_buffer_prepared_size */
1067  0                     /* MallocCfg_emergency_buffer_last_req */
1068};
1069IV *MallocCfg_ptr = MallocCfg;
1070
1071static char* MallocCfgP[MallocCfg_last] = {
1072  0,                    /* MallocCfgP_emergency_buffer */
1073  0,                    /* MallocCfgP_emergency_buffer_prepared */
1074};
1075char **MallocCfgP_ptr = MallocCfgP;
1076
1077#  undef MIN_SBRK
1078#  undef FIRST_SBRK
1079#  undef MIN_SBRK_FRAC1000
1080#  undef SBRK_ALLOW_FAILURES
1081#  undef SBRK_FAILURE_PRICE
1082
1083#  define MIN_SBRK              MallocCfg[MallocCfg_MIN_SBRK]
1084#  define FIRST_SBRK            MallocCfg[MallocCfg_FIRST_SBRK]
1085#  define MIN_SBRK_FRAC1000     MallocCfg[MallocCfg_MIN_SBRK_FRAC1000]
1086#  define SBRK_ALLOW_FAILURES   MallocCfg[MallocCfg_SBRK_ALLOW_FAILURES]
1087#  define SBRK_FAILURE_PRICE    MallocCfg[MallocCfg_SBRK_FAILURE_PRICE]
1088
1089#  define sbrk_goodness         MallocCfg[MallocCfg_sbrk_goodness]
1090
1091#  define emergency_buffer_size MallocCfg[MallocCfg_emergency_buffer_size]
1092#  define emergency_buffer_last_req     MallocCfg[MallocCfg_emergency_buffer_last_req]
1093
1094#  define FILL_DEAD             MallocCfg[MallocCfg_filldead]
1095#  define FILL_ALIVE            MallocCfg[MallocCfg_fillalive]
1096#  define FILL_CHECK_CFG        MallocCfg[MallocCfg_fillcheck]
1097#  define FILL_CHECK            (FILL_DEAD && FILL_CHECK_CFG)
1098
1099#  define emergency_buffer      MallocCfgP[MallocCfgP_emergency_buffer]
1100#  define emergency_buffer_prepared     MallocCfgP[MallocCfgP_emergency_buffer_prepared]
1101
1102#else   /* defined(NO_MALLOC_DYNAMIC_CFG) */
1103
1104#  define FILL_DEAD     1
1105#  define FILL_ALIVE    1
1106#  define FILL_CHECK    1
1107static int sbrk_goodness = SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE;
1108
1109#  define NO_PERL_MALLOC_ENV
1110
1111#endif
1112
1113#ifdef DEBUGGING_MSTATS
1114/*
1115 * nmalloc[i] is the difference between the number of mallocs and frees
1116 * for a given block size.
1117 */
1118static  u_int nmalloc[NBUCKETS];
1119static  u_int sbrk_slack;
1120static  u_int start_slack;
1121#else   /* !( defined DEBUGGING_MSTATS ) */
1122#  define sbrk_slack    0
1123#endif
1124
1125static  u_int goodsbrk;
1126
1127#ifdef PERL_EMERGENCY_SBRK
1128
1129#  ifndef BIG_SIZE
1130#    define BIG_SIZE (1<<16)            /* 64K */
1131#  endif
1132
1133#  ifdef NO_MALLOC_DYNAMIC_CFG
1134static MEM_SIZE emergency_buffer_size;
1135        /* 0 if the last request for more memory succeeded.
1136           Otherwise the size of the failing request. */
1137static MEM_SIZE emergency_buffer_last_req;
1138static char *emergency_buffer;
1139static char *emergency_buffer_prepared;
1140#  endif
1141
1142#  ifndef emergency_sbrk_croak
1143#    define emergency_sbrk_croak        croak2
1144#  endif
1145
1146#  ifdef PERL_CORE
1147static char *
1148perl_get_emergency_buffer(IV *size)
1149{
1150    dTHX;
1151    /* First offense, give a possibility to recover by dieing. */
1152    /* No malloc involved here: */
1153    GV **gvp = (GV**)hv_fetch(PL_defstash, "^M", 2, 0);
1154    SV *sv;
1155    char *pv;
1156    STRLEN n_a;
1157
1158    if (!gvp) gvp = (GV**)hv_fetch(PL_defstash, "\015", 1, 0);
1159    if (!gvp || !(sv = GvSV(*gvp)) || !SvPOK(sv)
1160        || (SvLEN(sv) < (1<<LOG_OF_MIN_ARENA) - M_OVERHEAD))
1161        return NULL;            /* Now die die die... */
1162    /* Got it, now detach SvPV: */
1163    pv = SvPV(sv, n_a);
1164    /* Check alignment: */
1165    if ((PTR2UV(pv) - sizeof(union overhead)) & (NEEDED_ALIGNMENT - 1)) {
1166        PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
1167        return NULL;            /* die die die */
1168    }
1169
1170    SvPOK_off(sv);
1171    SvPVX(sv) = Nullch;
1172    SvCUR(sv) = SvLEN(sv) = 0;
1173    *size = malloced_size(pv) + M_OVERHEAD;
1174    return pv - sizeof(union overhead);
1175}
1176#    define PERL_GET_EMERGENCY_BUFFER(p)        perl_get_emergency_buffer(p)
1177#  else
1178#    define PERL_GET_EMERGENCY_BUFFER(p)        NULL
1179#  endif        /* defined PERL_CORE */
1180
1181#  ifndef NO_MALLOC_DYNAMIC_CFG
1182static char *
1183get_emergency_buffer(IV *size)
1184{
1185    char *pv = emergency_buffer_prepared;
1186
1187    *size = MallocCfg[MallocCfg_emergency_buffer_prepared_size];
1188    emergency_buffer_prepared = 0;
1189    MallocCfg[MallocCfg_emergency_buffer_prepared_size] = 0;
1190    return pv;
1191}
1192
1193/* Returns 0 on success, -1 on bad alignment, -2 if not implemented */
1194int
1195set_emergency_buffer(char *b, IV size)
1196{
1197    if (PTR2UV(b) & (NEEDED_ALIGNMENT - 1))
1198        return -1;
1199    if (MallocCfg[MallocCfg_emergency_buffer_prepared_size])
1200        add_to_chain((void*)emergency_buffer_prepared,
1201                     MallocCfg[MallocCfg_emergency_buffer_prepared_size], 0);
1202    emergency_buffer_prepared = b;
1203    MallocCfg[MallocCfg_emergency_buffer_prepared_size] = size;
1204    return 0;
1205}
1206#    define GET_EMERGENCY_BUFFER(p)     get_emergency_buffer(p)
1207#  else         /* NO_MALLOC_DYNAMIC_CFG */
1208#    define GET_EMERGENCY_BUFFER(p)     NULL
1209int
1210set_emergency_buffer(char *b, IV size)
1211{
1212    return -1;
1213}
1214#  endif
1215
1216static Malloc_t
1217emergency_sbrk(MEM_SIZE size)
1218{
1219    MEM_SIZE rsize = (((size - 1)>>LOG_OF_MIN_ARENA) + 1)<<LOG_OF_MIN_ARENA;
1220
1221    if (size >= BIG_SIZE
1222        && (!emergency_buffer_last_req || (size < emergency_buffer_last_req))) {
1223        /* Give the possibility to recover, but avoid an infinite cycle. */
1224        MALLOC_UNLOCK;
1225        emergency_buffer_last_req = size;
1226        emergency_sbrk_croak("Out of memory during \"large\" request for %"UVuf" bytes, total sbrk() is %"UVuf" bytes", (UV)size, (UV)(goodsbrk + sbrk_slack));
1227    }
1228
1229    if (emergency_buffer_size >= rsize) {
1230        char *old = emergency_buffer;
1231       
1232        emergency_buffer_size -= rsize;
1233        emergency_buffer += rsize;
1234        return old;
1235    } else {           
1236        /* First offense, give a possibility to recover by dieing. */
1237        /* No malloc involved here: */
1238        IV Size;
1239        char *pv = GET_EMERGENCY_BUFFER(&Size);
1240        int have = 0;
1241
1242        if (emergency_buffer_size) {
1243            add_to_chain(emergency_buffer, emergency_buffer_size, 0);
1244            emergency_buffer_size = 0;
1245            emergency_buffer = Nullch;
1246            have = 1;
1247        }
1248
1249        if (!pv)
1250            pv = PERL_GET_EMERGENCY_BUFFER(&Size);
1251        if (!pv) {
1252            if (have)
1253                goto do_croak;
1254            return (char *)-1;          /* Now die die die... */
1255        }
1256
1257        /* Check alignment: */
1258        if (PTR2UV(pv) & (NEEDED_ALIGNMENT - 1)) {
1259            dTHX;
1260
1261            PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
1262            return (char *)-1;          /* die die die */
1263        }
1264
1265        emergency_buffer = pv;
1266        emergency_buffer_size = Size;
1267    }
1268  do_croak:
1269    MALLOC_UNLOCK;
1270    emergency_sbrk_croak("Out of memory during request for %"UVuf" bytes, total sbrk() is %"UVuf" bytes", (UV)size, (UV)(goodsbrk + sbrk_slack));
1271    /* NOTREACHED */
1272    return Nullch;
1273}
1274
1275#else /*  !defined(PERL_EMERGENCY_SBRK) */
1276#  define emergency_sbrk(size)  -1
1277#endif  /* defined PERL_EMERGENCY_SBRK */
1278
1279static void
1280write2(char *mess)
1281{
1282  write(2, mess, strlen(mess));
1283}
1284
1285#ifdef DEBUGGING
1286#undef ASSERT
1287#define ASSERT(p,diag)   if (!(p)) botch(diag,STRINGIFY(p),__FILE__,__LINE__);  else
1288static void
1289botch(char *diag, char *s, char *file, int line)
1290{
1291    if (!(PERL_MAYBE_ALIVE && PERL_GET_THX))
1292        goto do_write;
1293    else {
1294        dTHX;
1295        if (PerlIO_printf(PerlIO_stderr(),
1296                          "assertion botched (%s?): %s %s:%d\n",
1297                          diag, s, file, line) != 0) {
1298         do_write:              /* Can be initializing interpreter */
1299            write2("assertion botched (");
1300            write2(diag);
1301            write2("?): ");
1302            write2(s);
1303            write2(" (");
1304            write2(file);
1305            write2(":");
1306            {
1307              char linebuf[10];
1308              char *s = linebuf + sizeof(linebuf) - 1;
1309              int n = line;
1310              *s = 0;
1311              do {
1312                *--s = '0' + (n % 10);
1313              } while (n /= 10);
1314              write2(s);
1315            }
1316            write2(")\n");
1317        }
1318        PerlProc_abort();
1319    }
1320}
1321#else
1322#define ASSERT(p, diag)
1323#endif
1324
1325#ifdef MALLOC_FILL
1326/* Fill should be long enough to cover long */
1327static void
1328fill_pat_4bytes(unsigned char *s, size_t nbytes, const unsigned char *fill)
1329{
1330    unsigned char *e = s + nbytes;
1331    long *lp;
1332    long lfill = *(long*)fill;
1333
1334    if (PTR2UV(s) & (sizeof(long)-1)) {         /* Align the pattern */
1335        int shift = sizeof(long) - (PTR2UV(s) & (sizeof(long)-1));
1336        unsigned const char *f = fill + sizeof(long) - shift;
1337        unsigned char *e1 = s + shift;
1338
1339        while (s < e1)
1340            *s++ = *f++;
1341    }
1342    lp = (long*)s;
1343    while ((unsigned char*)(lp + 1) <= e)
1344        *lp++ = lfill;
1345    s = (unsigned char*)lp;
1346    while (s < e)
1347        *s++ = *fill++;
1348}
1349/* Just malloc()ed */
1350static const unsigned char fill_feedadad[] =
1351 {0xFE, 0xED, 0xAD, 0xAD, 0xFE, 0xED, 0xAD, 0xAD,
1352  0xFE, 0xED, 0xAD, 0xAD, 0xFE, 0xED, 0xAD, 0xAD};
1353/* Just free()ed */
1354static const unsigned char fill_deadbeef[] =
1355 {0xDE, 0xAD, 0xBE, 0xEF, 0xDE, 0xAD, 0xBE, 0xEF,
1356  0xDE, 0xAD, 0xBE, 0xEF, 0xDE, 0xAD, 0xBE, 0xEF};
1357#  define FILL_DEADBEEF(s, n)   \
1358        (void)(FILL_DEAD?  (fill_pat_4bytes((s), (n), fill_deadbeef), 0) : 0)
1359#  define FILL_FEEDADAD(s, n)   \
1360        (void)(FILL_ALIVE? (fill_pat_4bytes((s), (n), fill_feedadad), 0) : 0)
1361#else
1362#  define FILL_DEADBEEF(s, n)   ((void)0)
1363#  define FILL_FEEDADAD(s, n)   ((void)0)
1364#  undef MALLOC_FILL_CHECK
1365#endif
1366
1367#ifdef MALLOC_FILL_CHECK
1368static int
1369cmp_pat_4bytes(unsigned char *s, size_t nbytes, const unsigned char *fill)
1370{
1371    unsigned char *e = s + nbytes;
1372    long *lp;
1373    long lfill = *(long*)fill;
1374
1375    if (PTR2UV(s) & (sizeof(long)-1)) {         /* Align the pattern */
1376        int shift = sizeof(long) - (PTR2UV(s) & (sizeof(long)-1));
1377        unsigned const char *f = fill + sizeof(long) - shift;
1378        unsigned char *e1 = s + shift;
1379
1380        while (s < e1)
1381            if (*s++ != *f++)
1382                return 1;
1383    }
1384    lp = (long*)s;
1385    while ((unsigned char*)(lp + 1) <= e)
1386        if (*lp++ != lfill)
1387            return 1;
1388    s = (unsigned char*)lp;
1389    while (s < e)
1390        if (*s++ != *fill++)
1391            return 1;
1392    return 0;
1393}
1394#  define FILLCHECK_DEADBEEF(s, n)                                      \
1395        ASSERT(!FILL_CHECK || !cmp_pat_4bytes(s, n, fill_deadbeef),     \
1396               "free()ed/realloc()ed-away memory was overwritten")
1397#else
1398#  define FILLCHECK_DEADBEEF(s, n)      ((void)0)
1399#endif
1400
1401Malloc_t
1402Perl_malloc(register size_t nbytes)
1403{
1404        register union overhead *p;
1405        register int bucket;
1406        register MEM_SIZE shiftr;
1407
1408#if defined(DEBUGGING) || defined(RCHECK)
1409        MEM_SIZE size = nbytes;
1410#endif
1411
1412        BARK_64K_LIMIT("Allocation",nbytes,nbytes);
1413#ifdef DEBUGGING
1414        if ((long)nbytes < 0)
1415            croak("%s", "panic: malloc");
1416#endif
1417
1418        /*
1419         * Convert amount of memory requested into
1420         * closest block size stored in hash buckets
1421         * which satisfies request.  Account for
1422         * space used per block for accounting.
1423         */
1424#ifdef PACK_MALLOC
1425#  ifdef SMALL_BUCKET_VIA_TABLE
1426        if (nbytes == 0)
1427            bucket = MIN_BUCKET;
1428        else if (nbytes <= SIZE_TABLE_MAX) {
1429            bucket = bucket_of[(nbytes - 1) >> BUCKET_TABLE_SHIFT];
1430        } else
1431#  else
1432        if (nbytes == 0)
1433            nbytes = 1;
1434        if (nbytes <= MAX_POW2_ALGO) goto do_shifts;
1435        else
1436#  endif
1437#endif
1438        {
1439            POW2_OPTIMIZE_ADJUST(nbytes);
1440            nbytes += M_OVERHEAD;
1441            nbytes = (nbytes + 3) &~ 3;
1442#if defined(PACK_MALLOC) && !defined(SMALL_BUCKET_VIA_TABLE)
1443          do_shifts:
1444#endif
1445            shiftr = (nbytes - 1) >> START_SHIFT;
1446            bucket = START_SHIFTS_BUCKET;
1447            /* apart from this loop, this is O(1) */
1448            while (shiftr >>= 1)
1449                bucket += BUCKETS_PER_POW2;
1450        }
1451        MALLOC_LOCK;
1452        /*
1453         * If nothing in hash bucket right now,
1454         * request more memory from the system.
1455         */
1456        if (nextf[bucket] == NULL)   
1457                morecore(bucket);
1458        if ((p = nextf[bucket]) == NULL) {
1459                MALLOC_UNLOCK;
1460#ifdef PERL_CORE
1461                {
1462                    dTHX;
1463                    if (!PL_nomemok) {
1464#if defined(PLAIN_MALLOC) && defined(NO_FANCY_MALLOC)
1465                        PerlIO_puts(PerlIO_stderr(),"Out of memory!\n");
1466#else
1467                        char buff[80];
1468                        char *eb = buff + sizeof(buff) - 1;
1469                        char *s = eb;
1470                        size_t n = nbytes;
1471
1472                        PerlIO_puts(PerlIO_stderr(),"Out of memory during request for ");
1473#if defined(DEBUGGING) || defined(RCHECK)
1474                        n = size;
1475#endif
1476                        *s = 0;                 
1477                        do {
1478                            *--s = '0' + (n % 10);
1479                        } while (n /= 10);
1480                        PerlIO_puts(PerlIO_stderr(),s);
1481                        PerlIO_puts(PerlIO_stderr()," bytes, total sbrk() is ");
1482                        s = eb;
1483                        n = goodsbrk + sbrk_slack;
1484                        do {
1485                            *--s = '0' + (n % 10);
1486                        } while (n /= 10);
1487                        PerlIO_puts(PerlIO_stderr(),s);
1488                        PerlIO_puts(PerlIO_stderr()," bytes!\n");
1489#endif /* defined(PLAIN_MALLOC) && defined(NO_FANCY_MALLOC) */
1490                        my_exit(1);
1491                    }
1492                }
1493#endif
1494                return (NULL);
1495        }
1496
1497        /* remove from linked list */
1498#ifdef DEBUGGING
1499        if ( (PTR2UV(p) & (MEM_ALIGNBYTES - 1))
1500                                                /* Can't get this low */
1501             || (p && PTR2UV(p) < (1<<LOG_OF_MIN_ARENA)) ) {
1502            dTHX;
1503            PerlIO_printf(PerlIO_stderr(),
1504                          "Unaligned pointer in the free chain 0x%"UVxf"\n",
1505                          PTR2UV(p));
1506        }
1507        if ( (PTR2UV(p->ov_next) & (MEM_ALIGNBYTES - 1))
1508             || (p->ov_next && PTR2UV(p->ov_next) < (1<<LOG_OF_MIN_ARENA)) ) {
1509            dTHX;
1510            PerlIO_printf(PerlIO_stderr(),
1511                          "Unaligned `next' pointer in the free "
1512                          "chain 0x%"UVxf" at 0x%"UVxf"\n",
1513                          PTR2UV(p->ov_next), PTR2UV(p));
1514        }
1515#endif
1516        nextf[bucket] = p->ov_next;
1517
1518        MALLOC_UNLOCK;
1519
1520        DEBUG_m(PerlIO_printf(Perl_debug_log,
1521                              "0x%"UVxf": (%05lu) malloc %ld bytes\n",
1522                              PTR2UV((Malloc_t)(p + CHUNK_SHIFT)), (unsigned long)(PL_an++),
1523                              (long)size));
1524
1525        FILLCHECK_DEADBEEF((unsigned char*)(p + CHUNK_SHIFT),
1526                           BUCKET_SIZE_REAL(bucket) + RMAGIC_SZ);
1527
1528#ifdef IGNORE_SMALL_BAD_FREE
1529        if (bucket >= FIRST_BUCKET_WITH_CHECK)
1530#endif
1531            OV_MAGIC(p, bucket) = MAGIC;
1532#ifndef PACK_MALLOC
1533        OV_INDEX(p) = bucket;
1534#endif
1535#ifdef RCHECK
1536        /*
1537         * Record allocated size of block and
1538         * bound space with magic numbers.
1539         */
1540        p->ov_rmagic = RMAGIC;
1541        if (bucket <= MAX_SHORT_BUCKET) {
1542            int i;
1543           
1544            nbytes = size + M_OVERHEAD;
1545            p->ov_size = nbytes - 1;
1546            if ((i = nbytes & (RMAGIC_SZ-1))) {
1547                i = RMAGIC_SZ - i;
1548                while (i--) /* nbytes - RMAGIC_SZ is end of alloced area */
1549                    ((caddr_t)p + nbytes - RMAGIC_SZ)[i] = RMAGIC_C;
1550            }
1551            /* Same at RMAGIC_SZ-aligned RMAGIC */
1552            nbytes = (nbytes + RMAGIC_SZ - 1) & ~(RMAGIC_SZ - 1);
1553            ((u_int *)((caddr_t)p + nbytes))[-1] = RMAGIC;
1554        }
1555        FILL_FEEDADAD((unsigned char *)(p + CHUNK_SHIFT), size);
1556#endif
1557        return ((Malloc_t)(p + CHUNK_SHIFT));
1558}
1559
1560static char *last_sbrk_top;
1561static char *last_op;                   /* This arena can be easily extended. */
1562static MEM_SIZE sbrked_remains;
1563
1564#ifdef DEBUGGING_MSTATS
1565static int sbrks;
1566#endif
1567
1568struct chunk_chain_s {
1569    struct chunk_chain_s *next;
1570    MEM_SIZE size;
1571};
1572static struct chunk_chain_s *chunk_chain;
1573static int n_chunks;
1574static char max_bucket;
1575
1576/* Cutoff a piece of one of the chunks in the chain.  Prefer smaller chunk. */
1577static void *
1578get_from_chain(MEM_SIZE size)
1579{
1580    struct chunk_chain_s *elt = chunk_chain, **oldp = &chunk_chain;
1581    struct chunk_chain_s **oldgoodp = NULL;
1582    long min_remain = LONG_MAX;
1583
1584    while (elt) {
1585        if (elt->size >= size) {
1586            long remains = elt->size - size;
1587            if (remains >= 0 && remains < min_remain) {
1588                oldgoodp = oldp;
1589                min_remain = remains;
1590            }
1591            if (remains == 0) {
1592                break;
1593            }
1594        }
1595        oldp = &( elt->next );
1596        elt = elt->next;
1597    }
1598    if (!oldgoodp) return NULL;
1599    if (min_remain) {
1600        void *ret = *oldgoodp;
1601        struct chunk_chain_s *next = (*oldgoodp)->next;
1602       
1603        *oldgoodp = (struct chunk_chain_s *)((char*)ret + size);
1604        (*oldgoodp)->size = min_remain;
1605        (*oldgoodp)->next = next;
1606        return ret;
1607    } else {
1608        void *ret = *oldgoodp;
1609        *oldgoodp = (*oldgoodp)->next;
1610        n_chunks--;
1611        return ret;
1612    }
1613}
1614
1615static void
1616add_to_chain(void *p, MEM_SIZE size, MEM_SIZE chip)
1617{
1618    struct chunk_chain_s *next = chunk_chain;
1619    char *cp = (char*)p;
1620   
1621    cp += chip;
1622    chunk_chain = (struct chunk_chain_s *)cp;
1623    chunk_chain->size = size - chip;
1624    chunk_chain->next = next;
1625    n_chunks++;
1626}
1627
1628static void *
1629get_from_bigger_buckets(int bucket, MEM_SIZE size)
1630{
1631    int price = 1;
1632    static int bucketprice[NBUCKETS];
1633    while (bucket <= max_bucket) {
1634        /* We postpone stealing from bigger buckets until we want it
1635           often enough. */
1636        if (nextf[bucket] && bucketprice[bucket]++ >= price) {
1637            /* Steal it! */
1638            void *ret = (void*)(nextf[bucket] - 1 + CHUNK_SHIFT);
1639            bucketprice[bucket] = 0;
1640            if (((char*)nextf[bucket]) - M_OVERHEAD == last_op) {
1641                last_op = NULL;         /* Disable optimization */
1642            }
1643            nextf[bucket] = nextf[bucket]->ov_next;
1644#ifdef DEBUGGING_MSTATS
1645            nmalloc[bucket]--;
1646            start_slack -= M_OVERHEAD;
1647#endif
1648            add_to_chain(ret, (BUCKET_SIZE_NO_SURPLUS(bucket) +
1649                               POW2_OPTIMIZE_SURPLUS(bucket)),
1650                         size);
1651            return ret;
1652        }
1653        bucket++;
1654    }
1655    return NULL;
1656}
1657
1658static union overhead *
1659getpages(MEM_SIZE needed, int *nblksp, int bucket)
1660{
1661    /* Need to do (possibly expensive) system call. Try to
1662       optimize it for rare calling. */
1663    MEM_SIZE require = needed - sbrked_remains;
1664    char *cp;
1665    union overhead *ovp;
1666    MEM_SIZE slack = 0;
1667
1668    if (sbrk_goodness > 0) {
1669        if (!last_sbrk_top && require < FIRST_SBRK)
1670            require = FIRST_SBRK;
1671        else if (require < MIN_SBRK) require = MIN_SBRK;
1672
1673        if (require < goodsbrk * MIN_SBRK_FRAC1000 / 1000)
1674            require = goodsbrk * MIN_SBRK_FRAC1000 / 1000;
1675        require = ((require - 1 + MIN_SBRK) / MIN_SBRK) * MIN_SBRK;
1676    } else {
1677        require = needed;
1678        last_sbrk_top = 0;
1679        sbrked_remains = 0;
1680    }
1681
1682    DEBUG_m(PerlIO_printf(Perl_debug_log,
1683                          "sbrk(%ld) for %ld-byte-long arena\n",
1684                          (long)require, (long) needed));
1685    cp = (char *)sbrk(require);
1686#ifdef DEBUGGING_MSTATS
1687    sbrks++;
1688#endif
1689    if (cp == last_sbrk_top) {
1690        /* Common case, anything is fine. */
1691        sbrk_goodness++;
1692        ovp = (union overhead *) (cp - sbrked_remains);
1693        last_op = cp - sbrked_remains;
1694        sbrked_remains = require - (needed - sbrked_remains);
1695    } else if (cp == (char *)-1) { /* no more room! */
1696        ovp = (union overhead *)emergency_sbrk(needed);
1697        if (ovp == (union overhead *)-1)
1698            return 0;
1699        if (((char*)ovp) > last_op) {   /* Cannot happen with current emergency_sbrk() */
1700            last_op = 0;
1701        }
1702        return ovp;
1703    } else {                    /* Non-continuous or first sbrk(). */
1704        long add = sbrked_remains;
1705        char *newcp;
1706
1707        if (sbrked_remains) {   /* Put rest into chain, we
1708                                   cannot use it right now. */
1709            add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1710                         sbrked_remains, 0);
1711        }
1712
1713        /* Second, check alignment. */
1714        slack = 0;
1715
1716#if !defined(atarist) && !defined(__MINT__) /* on the atari we dont have to worry about this */
1717#  ifndef I286  /* The sbrk(0) call on the I286 always returns the next segment */
1718        /* WANTED_ALIGNMENT may be more than NEEDED_ALIGNMENT, but this may
1719           improve performance of memory access. */
1720        if (PTR2UV(cp) & (WANTED_ALIGNMENT - 1)) { /* Not aligned. */
1721            slack = WANTED_ALIGNMENT - (PTR2UV(cp) & (WANTED_ALIGNMENT - 1));
1722            add += slack;
1723        }
1724#  endif
1725#endif /* !atarist && !MINT */
1726               
1727        if (add) {
1728            DEBUG_m(PerlIO_printf(Perl_debug_log,
1729                                  "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",
1730                                  (long)add, (long) slack,
1731                                  (long) sbrked_remains));
1732            newcp = (char *)sbrk(add);
1733#if defined(DEBUGGING_MSTATS)
1734            sbrks++;
1735            sbrk_slack += add;
1736#endif
1737            if (newcp != cp + require) {
1738                /* Too bad: even rounding sbrk() is not continuous.*/
1739                DEBUG_m(PerlIO_printf(Perl_debug_log,
1740                                      "failed to fix bad sbrk()\n"));
1741#ifdef PACK_MALLOC
1742                if (slack) {
1743                    MALLOC_UNLOCK;
1744                    fatalcroak("panic: Off-page sbrk\n");
1745                }
1746#endif
1747                if (sbrked_remains) {
1748                    /* Try again. */
1749#if defined(DEBUGGING_MSTATS)
1750                    sbrk_slack += require;
1751#endif
1752                    require = needed;
1753                    DEBUG_m(PerlIO_printf(Perl_debug_log,
1754                                          "straight sbrk(%ld)\n",
1755                                          (long)require));
1756                    cp = (char *)sbrk(require);
1757#ifdef DEBUGGING_MSTATS
1758                    sbrks++;
1759#endif
1760                    if (cp == (char *)-1)
1761                        return 0;
1762                }
1763                sbrk_goodness = -1;     /* Disable optimization!
1764                                   Continue with not-aligned... */
1765            } else {
1766                cp += slack;
1767                require += sbrked_remains;
1768            }
1769        }
1770
1771        if (last_sbrk_top) {
1772            sbrk_goodness -= SBRK_FAILURE_PRICE;
1773        }
1774
1775        ovp = (union overhead *) cp;
1776        /*
1777         * Round up to minimum allocation size boundary
1778         * and deduct from block count to reflect.
1779         */
1780
1781#  if NEEDED_ALIGNMENT > MEM_ALIGNBYTES
1782        if (PTR2UV(ovp) & (NEEDED_ALIGNMENT - 1))
1783            fatalcroak("Misalignment of sbrk()\n");
1784        else
1785#  endif
1786#ifndef I286    /* Again, this should always be ok on an 80286 */
1787        if (PTR2UV(ovp) & (MEM_ALIGNBYTES - 1)) {
1788            DEBUG_m(PerlIO_printf(Perl_debug_log,
1789                                  "fixing sbrk(): %d bytes off machine alignement\n",
1790                                  (int)(PTR2UV(ovp) & (MEM_ALIGNBYTES - 1))));
1791            ovp = INT2PTR(union overhead *,(PTR2UV(ovp) + MEM_ALIGNBYTES) &
1792                                     (MEM_ALIGNBYTES - 1));
1793            (*nblksp)--;
1794# if defined(DEBUGGING_MSTATS)
1795            /* This is only approx. if TWO_POT_OPTIMIZE: */
1796            sbrk_slack += (1 << (bucket >> BUCKET_POW2_SHIFT));
1797# endif
1798        }
1799#endif
1800        ;                               /* Finish `else' */
1801        sbrked_remains = require - needed;
1802        last_op = cp;
1803    }
1804#if !defined(PLAIN_MALLOC) && !defined(NO_FANCY_MALLOC)
1805    emergency_buffer_last_req = 0;
1806#endif
1807    last_sbrk_top = cp + require;
1808#ifdef DEBUGGING_MSTATS
1809    goodsbrk += require;
1810#endif 
1811    return ovp;
1812}
1813
1814static int
1815getpages_adjacent(MEM_SIZE require)
1816{           
1817    if (require <= sbrked_remains) {
1818        sbrked_remains -= require;
1819    } else {
1820        char *cp;
1821
1822        require -= sbrked_remains;
1823        /* We do not try to optimize sbrks here, we go for place. */
1824        cp = (char*) sbrk(require);
1825#ifdef DEBUGGING_MSTATS
1826        sbrks++;
1827        goodsbrk += require;
1828#endif
1829        if (cp == last_sbrk_top) {
1830            sbrked_remains = 0;
1831            last_sbrk_top = cp + require;
1832        } else {
1833            if (cp == (char*)-1) {      /* Out of memory */
1834#ifdef DEBUGGING_MSTATS
1835                goodsbrk -= require;
1836#endif
1837                return 0;
1838            }
1839            /* Report the failure: */
1840            if (sbrked_remains)
1841                add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1842                             sbrked_remains, 0);
1843            add_to_chain((void*)cp, require, 0);
1844            sbrk_goodness -= SBRK_FAILURE_PRICE;
1845            sbrked_remains = 0;
1846            last_sbrk_top = 0;
1847            last_op = 0;
1848            return 0;
1849        }
1850    }
1851           
1852    return 1;
1853}
1854
1855/*
1856 * Allocate more memory to the indicated bucket.
1857 */
1858static void
1859morecore(register int bucket)
1860{
1861        register union overhead *ovp;
1862        register int rnu;       /* 2^rnu bytes will be requested */
1863        int nblks;              /* become nblks blocks of the desired size */
1864        register MEM_SIZE siz, needed;
1865        static int were_called = 0;
1866
1867        if (nextf[bucket])
1868                return;
1869#ifndef NO_PERL_MALLOC_ENV
1870        if (!were_called) {
1871            /* It's the our first time.  Initialize ourselves */
1872            were_called = 1;    /* Avoid a loop */
1873            if (!MallocCfg[MallocCfg_skip_cfg_env]) {
1874                char *s = getenv("PERL_MALLOC_OPT"), *t = s, *off;
1875                const char *opts = PERL_MALLOC_OPT_CHARS;
1876                int changed = 0;
1877
1878                while ( t && t[0] && t[1] == '='
1879                        && ((off = strchr(opts, *t))) ) {
1880                    IV val = 0;
1881
1882                    t += 2;
1883                    while (*t <= '9' && *t >= '0')
1884                        val = 10*val + *t++ - '0';
1885                    if (!*t || *t == ';') {
1886                        if (MallocCfg[off - opts] != val)
1887                            changed = 1;
1888                        MallocCfg[off - opts] = val;
1889                        if (*t)
1890                            t++;
1891                    }
1892                }
1893                if (t && *t) {
1894                    write2("Unrecognized part of PERL_MALLOC_OPT: `");
1895                    write2(t);
1896                    write2("'\n");
1897                }
1898                if (changed)
1899                    MallocCfg[MallocCfg_cfg_env_read] = 1;
1900            }
1901        }
1902#endif
1903        if (bucket == sizeof(MEM_SIZE)*8*BUCKETS_PER_POW2) {
1904            MALLOC_UNLOCK;
1905            croak("%s", "Out of memory during ridiculously large request");
1906        }
1907        if (bucket > max_bucket)
1908            max_bucket = bucket;
1909
1910        rnu = ( (bucket <= (LOG_OF_MIN_ARENA << BUCKET_POW2_SHIFT))
1911                ? LOG_OF_MIN_ARENA
1912                : (bucket >> BUCKET_POW2_SHIFT) );
1913        /* This may be overwritten later: */
1914        nblks = 1 << (rnu - (bucket >> BUCKET_POW2_SHIFT)); /* how many blocks to get */
1915        needed = ((MEM_SIZE)1 << rnu) + POW2_OPTIMIZE_SURPLUS(bucket);
1916        if (nextf[rnu << BUCKET_POW2_SHIFT]) { /* 2048b bucket. */
1917            ovp = nextf[rnu << BUCKET_POW2_SHIFT] - 1 + CHUNK_SHIFT;
1918            nextf[rnu << BUCKET_POW2_SHIFT]
1919                = nextf[rnu << BUCKET_POW2_SHIFT]->ov_next;
1920#ifdef DEBUGGING_MSTATS
1921            nmalloc[rnu << BUCKET_POW2_SHIFT]--;
1922            start_slack -= M_OVERHEAD;
1923#endif
1924            DEBUG_m(PerlIO_printf(Perl_debug_log,
1925                                  "stealing %ld bytes from %ld arena\n",
1926                                  (long) needed, (long) rnu << BUCKET_POW2_SHIFT));
1927        } else if (chunk_chain
1928                   && (ovp = (union overhead*) get_from_chain(needed))) {
1929            DEBUG_m(PerlIO_printf(Perl_debug_log,
1930                                  "stealing %ld bytes from chain\n",
1931                                  (long) needed));
1932        } else if ( (ovp = (union overhead*)
1933                     get_from_bigger_buckets((rnu << BUCKET_POW2_SHIFT) + 1,
1934                                             needed)) ) {
1935            DEBUG_m(PerlIO_printf(Perl_debug_log,
1936                                  "stealing %ld bytes from bigger buckets\n",
1937                                  (long) needed));
1938        } else if (needed <= sbrked_remains) {
1939            ovp = (union overhead *)(last_sbrk_top - sbrked_remains);
1940            sbrked_remains -= needed;
1941            last_op = (char*)ovp;
1942        } else
1943            ovp = getpages(needed, &nblks, bucket);
1944
1945        if (!ovp)
1946            return;
1947        FILL_DEADBEEF((unsigned char*)ovp, needed);
1948
1949        /*
1950         * Add new memory allocated to that on
1951         * free list for this hash bucket.
1952         */
1953        siz = BUCKET_SIZE_NO_SURPLUS(bucket); /* No surplus if nblks > 1 */
1954#ifdef PACK_MALLOC
1955        *(u_char*)ovp = bucket; /* Fill index. */
1956        if (bucket <= MAX_PACKED) {
1957            ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1958            nblks = N_BLKS(bucket);
1959#  ifdef DEBUGGING_MSTATS
1960            start_slack += BLK_SHIFT(bucket);
1961#  endif
1962        } else if (bucket < LOG_OF_MIN_ARENA * BUCKETS_PER_POW2) {
1963            ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1964            siz -= sizeof(union overhead);
1965        } else ovp++;           /* One chunk per block. */
1966#endif /* PACK_MALLOC */
1967        nextf[bucket] = ovp;
1968#ifdef DEBUGGING_MSTATS
1969        nmalloc[bucket] += nblks;
1970        if (bucket > MAX_PACKED) {
1971            start_slack += M_OVERHEAD * nblks;
1972        }
1973#endif
1974
1975        while (--nblks > 0) {
1976                ovp->ov_next = (union overhead *)((caddr_t)ovp + siz);
1977                ovp = (union overhead *)((caddr_t)ovp + siz);
1978        }
1979        /* Not all sbrks return zeroed memory.*/
1980        ovp->ov_next = (union overhead *)NULL;
1981#ifdef PACK_MALLOC
1982        if (bucket == 7*BUCKETS_PER_POW2) { /* Special case, explanation is above. */
1983            union overhead *n_op = nextf[7*BUCKETS_PER_POW2]->ov_next;
1984            nextf[7*BUCKETS_PER_POW2] =
1985                (union overhead *)((caddr_t)nextf[7*BUCKETS_PER_POW2]
1986                                   - sizeof(union overhead));
1987            nextf[7*BUCKETS_PER_POW2]->ov_next = n_op;
1988        }
1989#endif /* !PACK_MALLOC */
1990}
1991
1992Free_t
1993Perl_mfree(void *mp)
1994{
1995        register MEM_SIZE size;
1996        register union overhead *ovp;
1997        char *cp = (char*)mp;
1998#ifdef PACK_MALLOC
1999        u_char bucket;
2000#endif
2001
2002        DEBUG_m(PerlIO_printf(Perl_debug_log,
2003                              "0x%"UVxf": (%05lu) free\n",
2004                              PTR2UV(cp), (unsigned long)(PL_an++)));
2005
2006        if (cp == NULL)
2007                return;
2008#ifdef DEBUGGING
2009        if (PTR2UV(cp) & (MEM_ALIGNBYTES - 1))
2010            croak("%s", "wrong alignment in free()");
2011#endif
2012        ovp = (union overhead *)((caddr_t)cp
2013                                - sizeof (union overhead) * CHUNK_SHIFT);
2014#ifdef PACK_MALLOC
2015        bucket = OV_INDEX(ovp);
2016#endif
2017#ifdef IGNORE_SMALL_BAD_FREE
2018        if ((bucket >= FIRST_BUCKET_WITH_CHECK)
2019            && (OV_MAGIC(ovp, bucket) != MAGIC))
2020#else
2021        if (OV_MAGIC(ovp, bucket) != MAGIC)
2022#endif
2023            {
2024                static int bad_free_warn = -1;
2025                if (bad_free_warn == -1) {
2026                    dTHX;
2027                    char *pbf = PerlEnv_getenv("PERL_BADFREE");
2028                    bad_free_warn = (pbf) ? atoi(pbf) : 1;
2029                }
2030                if (!bad_free_warn)
2031                    return;
2032#ifdef RCHECK
2033#ifdef PERL_CORE
2034                {
2035                    dTHX;
2036                    if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
2037                        Perl_warner(aTHX_ packWARN(WARN_MALLOC), "%s free() ignored (RMAGIC, PERL_CORE)",
2038                                    ovp->ov_rmagic == RMAGIC - 1 ?
2039                                    "Duplicate" : "Bad");
2040                }
2041#else
2042                warn("%s free() ignored (RMAGIC)",
2043                    ovp->ov_rmagic == RMAGIC - 1 ? "Duplicate" : "Bad");
2044#endif         
2045#else
2046#ifdef PERL_CORE
2047                {
2048                    dTHX;
2049                    if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
2050                        Perl_warner(aTHX_ packWARN(WARN_MALLOC), "%s", "Bad free() ignored (PERL_CORE)");
2051                }
2052#else
2053                warn("%s", "Bad free() ignored");
2054#endif
2055#endif
2056                return;                         /* sanity */
2057            }
2058#ifdef RCHECK
2059        ASSERT(ovp->ov_rmagic == RMAGIC, "chunk's head overwrite");
2060        if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
2061            int i;
2062            MEM_SIZE nbytes = ovp->ov_size + 1;
2063
2064            if ((i = nbytes & (RMAGIC_SZ-1))) {
2065                i = RMAGIC_SZ - i;
2066                while (i--) {   /* nbytes - RMAGIC_SZ is end of alloced area */
2067                    ASSERT(((caddr_t)ovp + nbytes - RMAGIC_SZ)[i] == RMAGIC_C,
2068                           "chunk's tail overwrite");
2069                }
2070            }
2071            /* Same at RMAGIC_SZ-aligned RMAGIC */
2072            nbytes = (nbytes + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ-1);
2073            ASSERT(((u_int *)((caddr_t)ovp + nbytes))[-1] == RMAGIC,
2074                   "chunk's tail overwrite");       
2075            FILLCHECK_DEADBEEF((unsigned char*)((caddr_t)ovp + nbytes),
2076                               BUCKET_SIZE(OV_INDEX(ovp)) - nbytes);
2077        }
2078        FILL_DEADBEEF((unsigned char*)(ovp+CHUNK_SHIFT),
2079                      BUCKET_SIZE_REAL(OV_INDEX(ovp)) + RMAGIC_SZ);
2080        ovp->ov_rmagic = RMAGIC - 1;
2081#endif
2082        ASSERT(OV_INDEX(ovp) < NBUCKETS, "chunk's head overwrite");
2083        size = OV_INDEX(ovp);
2084
2085        MALLOC_LOCK;
2086        ovp->ov_next = nextf[size];
2087        nextf[size] = ovp;
2088        MALLOC_UNLOCK;
2089}
2090
2091/* There is no need to do any locking in realloc (with an exception of
2092   trying to grow in place if we are at the end of the chain).
2093   If somebody calls us from a different thread with the same address,
2094   we are sole anyway.  */
2095
2096Malloc_t
2097Perl_realloc(void *mp, size_t nbytes)
2098{
2099        register MEM_SIZE onb;
2100        union overhead *ovp;
2101        char *res;
2102        int prev_bucket;
2103        register int bucket;
2104        int incr;               /* 1 if does not fit, -1 if "easily" fits in a
2105                                   smaller bucket, otherwise 0.  */
2106        char *cp = (char*)mp;
2107
2108#if defined(DEBUGGING) || !defined(PERL_CORE)
2109        MEM_SIZE size = nbytes;
2110
2111        if ((long)nbytes < 0)
2112            croak("%s", "panic: realloc");
2113#endif
2114
2115        BARK_64K_LIMIT("Reallocation",nbytes,size);
2116        if (!cp)
2117                return Perl_malloc(nbytes);
2118
2119        ovp = (union overhead *)((caddr_t)cp
2120                                - sizeof (union overhead) * CHUNK_SHIFT);
2121        bucket = OV_INDEX(ovp);
2122
2123#ifdef IGNORE_SMALL_BAD_FREE
2124        if ((bucket >= FIRST_BUCKET_WITH_CHECK)
2125            && (OV_MAGIC(ovp, bucket) != MAGIC))
2126#else
2127        if (OV_MAGIC(ovp, bucket) != MAGIC)
2128#endif
2129            {
2130                static int bad_free_warn = -1;
2131                if (bad_free_warn == -1) {
2132                    dTHX;
2133                    char *pbf = PerlEnv_getenv("PERL_BADFREE");
2134                    bad_free_warn = (pbf) ? atoi(pbf) : 1;
2135                }
2136                if (!bad_free_warn)
2137                    return Nullch;
2138#ifdef RCHECK
2139#ifdef PERL_CORE
2140                {
2141                    dTHX;
2142                    if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
2143                        Perl_warner(aTHX_ packWARN(WARN_MALLOC), "%srealloc() %signored",
2144                                    (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
2145                                    ovp->ov_rmagic == RMAGIC - 1
2146                                    ? "of freed memory " : "");
2147                }
2148#else
2149                warn2("%srealloc() %signored",
2150                      (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
2151                      ovp->ov_rmagic == RMAGIC - 1 ? "of freed memory " : "");
2152#endif
2153#else
2154#ifdef PERL_CORE
2155                {
2156                    dTHX;
2157                    if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
2158                        Perl_warner(aTHX_ packWARN(WARN_MALLOC), "%s",
2159                                    "Bad realloc() ignored");
2160                }
2161#else
2162                warn("%s", "Bad realloc() ignored");
2163#endif
2164#endif
2165                return Nullch;                  /* sanity */
2166            }
2167
2168        onb = BUCKET_SIZE_REAL(bucket);
2169        /*
2170         *  avoid the copy if same size block.
2171         *  We are not agressive with boundary cases. Note that it might
2172         *  (for a small number of cases) give false negative if
2173         *  both new size and old one are in the bucket for
2174         *  FIRST_BIG_POW2, but the new one is near the lower end.
2175         *
2176         *  We do not try to go to 1.5 times smaller bucket so far.
2177         */
2178        if (nbytes > onb) incr = 1;
2179        else {
2180#ifdef DO_NOT_TRY_HARDER_WHEN_SHRINKING
2181            if ( /* This is a little bit pessimal if PACK_MALLOC: */
2182                nbytes > ( (onb >> 1) - M_OVERHEAD )
2183#  ifdef TWO_POT_OPTIMIZE
2184                || (bucket == FIRST_BIG_POW2 && nbytes >= LAST_SMALL_BOUND )
2185#  endif       
2186                )
2187#else  /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
2188                prev_bucket = ( (bucket > MAX_PACKED + 1)
2189                                ? bucket - BUCKETS_PER_POW2
2190                                : bucket - 1);
2191             if (nbytes > BUCKET_SIZE_REAL(prev_bucket))
2192#endif /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
2193                 incr = 0;
2194             else incr = -1;
2195        }
2196#ifdef STRESS_REALLOC
2197        goto hard_way;
2198#endif
2199        if (incr == 0) {
2200          inplace_label:
2201#ifdef RCHECK
2202                /*
2203                 * Record new allocated size of block and
2204                 * bound space with magic numbers.
2205                 */
2206                if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
2207                       int i, nb = ovp->ov_size + 1;
2208
2209                       if ((i = nb & (RMAGIC_SZ-1))) {
2210                           i = RMAGIC_SZ - i;
2211                           while (i--) { /* nb - RMAGIC_SZ is end of alloced area */
2212                               ASSERT(((caddr_t)ovp + nb - RMAGIC_SZ)[i] == RMAGIC_C, "chunk's tail overwrite");
2213                           }
2214                       }
2215                       /* Same at RMAGIC_SZ-aligned RMAGIC */
2216                       nb = (nb + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ-1);
2217                       ASSERT(((u_int *)((caddr_t)ovp + nb))[-1] == RMAGIC,
2218                              "chunk's tail overwrite");
2219                       FILLCHECK_DEADBEEF((unsigned char*)((caddr_t)ovp + nb),
2220                                          BUCKET_SIZE(OV_INDEX(ovp)) - nb);
2221                       if (nbytes > ovp->ov_size + 1 - M_OVERHEAD)
2222                           FILL_FEEDADAD((unsigned char*)cp + ovp->ov_size + 1 - M_OVERHEAD,
2223                                     nbytes - (ovp->ov_size + 1 - M_OVERHEAD));
2224                       else
2225                           FILL_DEADBEEF((unsigned char*)cp + nbytes,
2226                                         nb - M_OVERHEAD + RMAGIC_SZ - nbytes);
2227                        /*
2228                         * Convert amount of memory requested into
2229                         * closest block size stored in hash buckets
2230                         * which satisfies request.  Account for
2231                         * space used per block for accounting.
2232                         */
2233                        nbytes += M_OVERHEAD;
2234                        ovp->ov_size = nbytes - 1;
2235                        if ((i = nbytes & (RMAGIC_SZ-1))) {
2236                            i = RMAGIC_SZ - i;
2237                            while (i--) /* nbytes - RMAGIC_SZ is end of alloced area */
2238                                ((caddr_t)ovp + nbytes - RMAGIC_SZ)[i]
2239                                    = RMAGIC_C;
2240                        }
2241                        /* Same at RMAGIC_SZ-aligned RMAGIC */
2242                        nbytes = (nbytes + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ - 1);
2243                        ((u_int *)((caddr_t)ovp + nbytes))[-1] = RMAGIC;
2244                }
2245#endif
2246                res = cp;
2247                DEBUG_m(PerlIO_printf(Perl_debug_log,
2248                              "0x%"UVxf": (%05lu) realloc %ld bytes inplace\n",
2249                              PTR2UV(res),(unsigned long)(PL_an++),
2250                              (long)size));
2251        } else if (incr == 1 && (cp - M_OVERHEAD == last_op)
2252                   && (onb > (1 << LOG_OF_MIN_ARENA))) {
2253            MEM_SIZE require, newarena = nbytes, pow;
2254            int shiftr;
2255
2256            POW2_OPTIMIZE_ADJUST(newarena);
2257            newarena = newarena + M_OVERHEAD;
2258            /* newarena = (newarena + 3) &~ 3; */
2259            shiftr = (newarena - 1) >> LOG_OF_MIN_ARENA;
2260            pow = LOG_OF_MIN_ARENA + 1;
2261            /* apart from this loop, this is O(1) */
2262            while (shiftr >>= 1)
2263                pow++;
2264            newarena = (1 << pow) + POW2_OPTIMIZE_SURPLUS(pow * BUCKETS_PER_POW2);
2265            require = newarena - onb - M_OVERHEAD;
2266           
2267            MALLOC_LOCK;
2268            if (cp - M_OVERHEAD == last_op /* We *still* are the last chunk */
2269                && getpages_adjacent(require)) {
2270#ifdef DEBUGGING_MSTATS
2271                nmalloc[bucket]--;
2272                nmalloc[pow * BUCKETS_PER_POW2]++;
2273#endif     
2274                *(cp - M_OVERHEAD) = pow * BUCKETS_PER_POW2; /* Fill index. */
2275                MALLOC_UNLOCK;
2276                goto inplace_label;
2277            } else {
2278                MALLOC_UNLOCK;         
2279                goto hard_way;
2280            }
2281        } else {
2282          hard_way:
2283            DEBUG_m(PerlIO_printf(Perl_debug_log,
2284                              "0x%"UVxf": (%05lu) realloc %ld bytes the hard way\n",
2285                              PTR2UV(cp),(unsigned long)(PL_an++),
2286                              (long)size));
2287            if ((res = (char*)Perl_malloc(nbytes)) == NULL)
2288                return (NULL);
2289            if (cp != res)                      /* common optimization */
2290                Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char);
2291            Perl_mfree(cp);
2292        }
2293        return ((Malloc_t)res);
2294}
2295
2296Malloc_t
2297Perl_calloc(register size_t elements, register size_t size)
2298{
2299    long sz = elements * size;
2300    Malloc_t p = Perl_malloc(sz);
2301
2302    if (p) {
2303        memset((void*)p, 0, sz);
2304    }
2305    return p;
2306}
2307
2308char *
2309Perl_strdup(const char *s)
2310{
2311    MEM_SIZE l = strlen(s);
2312    char *s1 = (char *)Perl_malloc(l+1);
2313
2314    Copy(s, s1, (MEM_SIZE)(l+1), char);
2315    return s1;
2316}
2317
2318#ifdef PERL_CORE
2319int
2320Perl_putenv(char *a)
2321{
2322    /* Sometimes system's putenv conflicts with my_setenv() - this is system
2323       malloc vs Perl's free(). */
2324  dTHX;
2325  char *var;
2326  char *val = a;
2327  MEM_SIZE l;
2328  char buf[80];
2329
2330  while (*val && *val != '=')
2331      val++;
2332  if (!*val)
2333      return -1;
2334  l = val - a;
2335  if (l < sizeof(buf))
2336      var = buf;
2337  else
2338      var = Perl_malloc(l + 1);
2339  Copy(a, var, l, char);
2340  var[l + 1] = 0;
2341  my_setenv(var, val+1);
2342  if (var != buf)
2343      Perl_mfree(var);
2344  return 0;
2345}
2346#  endif
2347
2348MEM_SIZE
2349Perl_malloced_size(void *p)
2350{
2351    union overhead *ovp = (union overhead *)
2352        ((caddr_t)p - sizeof (union overhead) * CHUNK_SHIFT);
2353    int bucket = OV_INDEX(ovp);
2354#ifdef RCHECK
2355    /* The caller wants to have a complete control over the chunk,
2356       disable the memory checking inside the chunk.  */
2357    if (bucket <= MAX_SHORT_BUCKET) {
2358        MEM_SIZE size = BUCKET_SIZE_REAL(bucket);
2359        ovp->ov_size = size + M_OVERHEAD - 1;
2360        *((u_int *)((caddr_t)ovp + size + M_OVERHEAD - RMAGIC_SZ)) = RMAGIC;
2361    }
2362#endif
2363    return BUCKET_SIZE_REAL(bucket);
2364}
2365
2366#  ifdef BUCKETS_ROOT2
2367#    define MIN_EVEN_REPORT 6
2368#  else
2369#    define MIN_EVEN_REPORT MIN_BUCKET
2370#  endif
2371
2372int
2373Perl_get_mstats(pTHX_ perl_mstats_t *buf, int buflen, int level)
2374{
2375#ifdef DEBUGGING_MSTATS
2376        register int i, j;
2377        register union overhead *p;
2378        struct chunk_chain_s* nextchain;
2379
2380        buf->topbucket = buf->topbucket_ev = buf->topbucket_odd
2381            = buf->totfree = buf->total = buf->total_chain = 0;
2382
2383        buf->minbucket = MIN_BUCKET;
2384        MALLOC_LOCK;
2385        for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
2386                for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
2387                        ;
2388                if (i < buflen) {
2389                    buf->nfree[i] = j;
2390                    buf->ntotal[i] = nmalloc[i];
2391                }               
2392                buf->totfree += j * BUCKET_SIZE_REAL(i);
2393                buf->total += nmalloc[i] * BUCKET_SIZE_REAL(i);
2394                if (nmalloc[i]) {
2395                    i % 2 ? (buf->topbucket_odd = i) : (buf->topbucket_ev = i);
2396                    buf->topbucket = i;
2397                }
2398        }
2399        nextchain = chunk_chain;
2400        while (nextchain) {
2401            buf->total_chain += nextchain->size;
2402            nextchain = nextchain->next;
2403        }
2404        buf->total_sbrk = goodsbrk + sbrk_slack;
2405        buf->sbrks = sbrks;
2406        buf->sbrk_good = sbrk_goodness;
2407        buf->sbrk_slack = sbrk_slack;
2408        buf->start_slack = start_slack;
2409        buf->sbrked_remains = sbrked_remains;
2410        MALLOC_UNLOCK;
2411        buf->nbuckets = NBUCKETS;
2412        if (level) {
2413            for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
2414                if (i >= buflen)
2415                    break;
2416                buf->bucket_mem_size[i] = BUCKET_SIZE_NO_SURPLUS(i);
2417                buf->bucket_available_size[i] = BUCKET_SIZE_REAL(i);
2418            }
2419        }
2420#endif  /* defined DEBUGGING_MSTATS */
2421        return 0;               /* XXX unused */
2422}
2423/*
2424 * mstats - print out statistics about malloc
2425 *
2426 * Prints two lines of numbers, one showing the length of the free list
2427 * for each size category, the second showing the number of mallocs -
2428 * frees for each size category.
2429 */
2430void
2431Perl_dump_mstats(pTHX_ char *s)
2432{
2433#ifdef DEBUGGING_MSTATS
2434        register int i;
2435        perl_mstats_t buffer;
2436        UV nf[NBUCKETS];
2437        UV nt[NBUCKETS];
2438
2439        buffer.nfree  = nf;
2440        buffer.ntotal = nt;
2441        get_mstats(&buffer, NBUCKETS, 0);
2442
2443        if (s)
2444            PerlIO_printf(Perl_error_log,
2445                          "Memory allocation statistics %s (buckets %"IVdf"(%"IVdf")..%"IVdf"(%"IVdf")\n",
2446                          s,
2447                          (IV)BUCKET_SIZE_REAL(MIN_BUCKET),
2448                          (IV)BUCKET_SIZE_NO_SURPLUS(MIN_BUCKET),
2449                          (IV)BUCKET_SIZE_REAL(buffer.topbucket),
2450                          (IV)BUCKET_SIZE_NO_SURPLUS(buffer.topbucket));
2451        PerlIO_printf(Perl_error_log, "%8"IVdf" free:", buffer.totfree);
2452        for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
2453                PerlIO_printf(Perl_error_log,
2454                              ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2455                               ? " %5"UVuf
2456                               : ((i < 12*BUCKETS_PER_POW2) ? " %3"UVuf : " %"UVuf)),
2457                              buffer.nfree[i]);
2458        }
2459#ifdef BUCKETS_ROOT2
2460        PerlIO_printf(Perl_error_log, "\n\t   ");
2461        for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
2462                PerlIO_printf(Perl_error_log,
2463                              ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2464                               ? " %5"UVuf
2465                               : ((i < 12*BUCKETS_PER_POW2) ? " %3"UVuf : " %"UVuf)),
2466                              buffer.nfree[i]);
2467        }
2468#endif
2469        PerlIO_printf(Perl_error_log, "\n%8"IVdf" used:", buffer.total - buffer.totfree);
2470        for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
2471                PerlIO_printf(Perl_error_log,
2472                              ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2473                               ? " %5"IVdf
2474                               : ((i < 12*BUCKETS_PER_POW2) ? " %3"IVdf : " %"IVdf)),
2475                              buffer.ntotal[i] - buffer.nfree[i]);
2476        }
2477#ifdef BUCKETS_ROOT2
2478        PerlIO_printf(Perl_error_log, "\n\t   ");
2479        for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
2480                PerlIO_printf(Perl_error_log,
2481                              ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2482                               ? " %5"IVdf
2483                               : ((i < 12*BUCKETS_PER_POW2) ? " %3"IVdf : " %"IVdf)),
2484                              buffer.ntotal[i] - buffer.nfree[i]);
2485        }
2486#endif
2487        PerlIO_printf(Perl_error_log, "\nTotal sbrk(): %"IVdf"/%"IVdf":%"IVdf". Odd ends: pad+heads+chain+tail: %"IVdf"+%"IVdf"+%"IVdf"+%"IVdf".\n",
2488                      buffer.total_sbrk, buffer.sbrks, buffer.sbrk_good,
2489                      buffer.sbrk_slack, buffer.start_slack,
2490                      buffer.total_chain, buffer.sbrked_remains);
2491#endif /* DEBUGGING_MSTATS */
2492}
2493#endif /* lint */
2494
2495#ifdef USE_PERL_SBRK
2496
2497#   if defined(__MACHTEN_PPC__) || defined(NeXT) || defined(__NeXT__) || defined(PURIFY)
2498#      define PERL_SBRK_VIA_MALLOC
2499#   endif
2500
2501#   ifdef PERL_SBRK_VIA_MALLOC
2502
2503/* it may seem schizophrenic to use perl's malloc and let it call system */
2504/* malloc, the reason for that is only the 3.2 version of the OS that had */
2505/* frequent core dumps within nxzonefreenolock. This sbrk routine put an */
2506/* end to the cores */
2507
2508#      ifndef SYSTEM_ALLOC
2509#         define SYSTEM_ALLOC(a) malloc(a)
2510#      endif
2511#      ifndef SYSTEM_ALLOC_ALIGNMENT
2512#         define SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES
2513#      endif
2514
2515#   endif  /* PERL_SBRK_VIA_MALLOC */
2516
2517static IV Perl_sbrk_oldchunk;
2518static long Perl_sbrk_oldsize;
2519
2520#   define PERLSBRK_32_K (1<<15)
2521#   define PERLSBRK_64_K (1<<16)
2522
2523Malloc_t
2524Perl_sbrk(int size)
2525{
2526    IV got;
2527    int small, reqsize;
2528
2529    if (!size) return 0;
2530#ifdef PERL_CORE
2531    reqsize = size; /* just for the DEBUG_m statement */
2532#endif
2533#ifdef PACK_MALLOC
2534    size = (size + 0x7ff) & ~0x7ff;
2535#endif
2536    if (size <= Perl_sbrk_oldsize) {
2537        got = Perl_sbrk_oldchunk;
2538        Perl_sbrk_oldchunk += size;
2539        Perl_sbrk_oldsize -= size;
2540    } else {
2541      if (size >= PERLSBRK_32_K) {
2542        small = 0;
2543      } else {
2544        size = PERLSBRK_64_K;
2545        small = 1;
2546      }
2547#  if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2548      size += NEEDED_ALIGNMENT - SYSTEM_ALLOC_ALIGNMENT;
2549#  endif
2550      got = (IV)SYSTEM_ALLOC(size);
2551#  if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2552      got = (got + NEEDED_ALIGNMENT - 1) & ~(NEEDED_ALIGNMENT - 1);
2553#  endif
2554      if (small) {
2555        /* Chunk is small, register the rest for future allocs. */
2556        Perl_sbrk_oldchunk = got + reqsize;
2557        Perl_sbrk_oldsize = size - reqsize;
2558      }
2559    }
2560
2561    DEBUG_m(PerlIO_printf(Perl_debug_log, "sbrk malloc size %ld (reqsize %ld), left size %ld, give addr 0x%"UVxf"\n",
2562                    size, reqsize, Perl_sbrk_oldsize, PTR2UV(got)));
2563
2564    return (void *)got;
2565}
2566
2567#endif /* ! defined USE_PERL_SBRK */
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