6 * "'The Chamber of Records,' said Gimli. 'I guess that is where we now stand.'"
10 Here are some notes on configuring Perl's malloc. (For non-perl
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.
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).
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.
30 # Read configuration settings from malloc_cfg.h
31 HAVE_MALLOC_CFG_H undef
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))
37 # Enable code for printing memory statistics.
38 DEBUGGING_MSTATS (!PLAIN_MALLOC && PERL_CORE)
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)
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
49 TWO_POT_OPTIMIZE !PLAIN_MALLOC
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
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)
59 # Use table lookup to decide in which bucket a given allocation will go.
60 SMALL_BUCKET_VIA_TABLE !NO_FANCY_MALLOC
62 # Use a perl-defined sbrk() instead of the (presumably broken or
63 # missing) system-supplied sbrk().
66 # Use system malloc() (or calloc() etc.) to emulate sbrk(). Normally
67 # only used with broken sbrk()s.
68 PERL_SBRK_VIA_MALLOC undef
70 # Which allocator to use if PERL_SBRK_VIA_MALLOC
71 SYSTEM_ALLOC(a) malloc(a)
73 # Minimal alignment (in bytes, should be a power of 2) of SYSTEM_ALLOC
74 SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES
76 # Disable memory overwrite checking with DEBUGGING. Memory and speed
77 # optimization, error reporting pessimization.
80 # Enable memory overwrite checking with DEBUGGING. Memory and speed
81 # pessimization, error reporting optimization
82 RCHECK (DEBUGGING && !NO_RCHECK)
84 # Do not overwrite uninit areas with DEBUGGING. Speed
85 # optimization, error reporting pessimization
88 # Overwrite uninit areas with DEBUGGING. Speed
89 # pessimization, error reporting optimization
90 MALLOC_FILL (DEBUGGING && !NO_RCHECK && !NO_MFILL)
92 # Do not check overwritten uninit areas with DEBUGGING. Speed
93 # optimization, error reporting pessimization
96 # Check overwritten uninit areas with DEBUGGING. Speed
97 # pessimization, error reporting optimization
98 MALLOC_FILL_CHECK (DEBUGGING && !NO_RCHECK && !NO_FILL_CHECK)
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
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
110 # Estimate of minimal memory footprint. malloc uses this value to
111 # request the most reasonable largest blocks of memory from the system.
114 # Round up sbrk()s to multiples of this.
117 # Round up sbrk()s to multiples of this percent of footprint.
120 # Round up sbrk()s to multiples of this multiple of 1/1000 of footprint.
121 MIN_SBRK_FRAC1000 (10 * MIN_SBRK_FRAC)
123 # Add this much memory to big powers of two to get the bucket size.
126 # This many sbrk() discontinuities should be tolerated even
127 # from the start without deciding that sbrk() is usually
129 SBRK_ALLOW_FAILURES 3
131 # This many continuous sbrk()s compensate for one discontinuous one.
132 SBRK_FAILURE_PRICE 50
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
139 # Do not allow configuration of runtime options at runtime
140 NO_MALLOC_DYNAMIC_CFG undef
142 # Do not allow configuration of runtime options via $ENV{PERL_MALLOC_OPT}
143 NO_PERL_MALLOC_ENV undef
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.]
153 This implementation assumes that calling PerlIO_printf() does not
154 result in any memory allocation calls (used during a panic).
159 If used outside of Perl environment, it may be useful to redefine
160 the following macros (listed below with defaults):
162 # Type of address returned by allocation functions
165 # Type of size argument for allocation functions
166 MEM_SIZE unsigned long
171 # Maximal value in LONG
174 # Unsigned integer type big enough to keep a pointer
177 # Signed integer of the same sizeof() as UV
180 # Type of pointer with 1-byte granularity
183 # Type returned by free()
186 # Conversion of pointer to integer
187 PTR2UV(ptr) ((UV)(ptr))
189 # Conversion of integer to pointer
190 INT2PTR(type, i) ((type)(i))
192 # printf()-%-Conversion of UV to pointer
195 # printf()-%-Conversion of UV to hex pointer
201 # Very fatal condition reporting function (cannot call any )
202 fatalcroak(arg) write(2,arg,strlen(arg)) + exit(2)
204 # Fatal error reporting function
205 croak(format, arg) warn(idem) + exit(1)
207 # Fatal error reporting function
208 croak2(format, arg1, arg2) warn2(idem) + exit(1)
210 # Error reporting function
211 warn(format, arg) fprintf(stderr, idem)
213 # Error reporting function
214 warn2(format, arg1, arg2) fprintf(stderr, idem)
216 # Locking/unlocking for MT operation
217 MALLOC_LOCK MUTEX_LOCK(&PL_malloc_mutex)
218 MALLOC_UNLOCK MUTEX_UNLOCK(&PL_malloc_mutex)
220 # Locking/unlocking mutex for MT operation
225 #ifdef HAVE_MALLOC_CFG_H
226 # include "malloc_cfg.h"
229 #ifndef NO_FANCY_MALLOC
230 # ifndef SMALL_BUCKET_VIA_TABLE
231 # define SMALL_BUCKET_VIA_TABLE
233 # ifndef BUCKETS_ROOT2
234 # define BUCKETS_ROOT2
236 # ifndef IGNORE_SMALL_BAD_FREE
237 # define IGNORE_SMALL_BAD_FREE
241 #ifndef PLAIN_MALLOC /* Bulk enable features */
245 # ifndef TWO_POT_OPTIMIZE
246 # define TWO_POT_OPTIMIZE
248 # if (defined(PERL_CORE) || !defined(NO_MALLOC_DYNAMIC_CFG)) && !defined(PERL_EMERGENCY_SBRK)
249 # define PERL_EMERGENCY_SBRK
251 # if defined(PERL_CORE) && !defined(DEBUGGING_MSTATS)
252 # define DEBUGGING_MSTATS
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)
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
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
269 # if defined(DEBUGGING) && !defined(NO_RCHECK)
272 # if defined(DEBUGGING) && !defined(NO_RCHECK) && !defined(NO_MFILL) && !defined(MALLOC_FILL)
275 # if defined(DEBUGGING) && !defined(NO_RCHECK) && !defined(NO_FILL_CHECK) && !defined(MALLOC_FILL_CHECK)
276 # define MALLOC_FILL_CHECK
278 # if defined(RCHECK) && defined(IGNORE_SMALL_BAD_FREE)
279 # undef IGNORE_SMALL_BAD_FREE
282 * malloc.c (Caltech) 2/21/82
283 * Chris Kingsley, kingsley@cit-20.
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.
293 * Modifications Copyright Ilya Zakharevich 1996-99.
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.)
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.
307 # define PERL_IN_MALLOC_C
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
315 # define croak2 croak
318 # if defined(USE_5005THREADS) || defined(USE_ITHREADS)
319 # define PERL_MAYBE_ALIVE PL_thr_key
321 # define PERL_MAYBE_ALIVE 1
325 # include "../EXTERN.h"
326 # include "../perl.h"
336 # define Malloc_t void *
342 # define MEM_SIZE unsigned long
345 # define LONG_MAX 0x7FFFFFFF
348 # define UV unsigned long
354 # define caddr_t char *
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)
365 # define INT2PTR(t,i) ((t)(i))
368 # define PTR2UV(p) ((UV)(p))
379 # ifndef MEM_ALIGNBYTES
380 # define MEM_ALIGNBYTES 4
383 # ifndef croak /* make depend */
384 # define croak(mess, arg) (warn((mess), (arg)), exit(1))
386 # ifndef croak2 /* make depend */
387 # define croak2(mess, arg1, arg2) (warn2((mess), (arg1), (arg2)), exit(1))
390 # define warn(mess, arg) fprintf(stderr, (mess), (arg))
393 # define warn2(mess, arg1, arg2) fprintf(stderr, (mess), (arg1), (arg2))
406 # define dTHX extern int Perl___notused PERL_UNUSED_DECL
408 # define dTHX extern int Perl___notused
410 # define WITH_THX(s) s
412 # ifndef PERL_GET_INTERP
413 # define PERL_GET_INTERP PL_curinterp
415 # define PERL_MAYBE_ALIVE 1
417 # define Perl_malloc malloc
420 # define Perl_mfree free
422 # ifndef Perl_realloc
423 # define Perl_realloc realloc
426 # define Perl_calloc calloc
429 # define Perl_strdup strdup
431 #endif /* defined PERL_CORE */
434 # define MUTEX_LOCK(l)
438 # define MUTEX_UNLOCK(l)
442 # define MALLOC_LOCK MUTEX_LOCK(&PL_malloc_mutex)
445 #ifndef MALLOC_UNLOCK
446 # define MALLOC_UNLOCK MUTEX_UNLOCK(&PL_malloc_mutex)
449 # ifndef fatalcroak /* make depend */
450 # define fatalcroak(mess) (write(2, (mess), strlen(mess)), exit(2))
455 # define DEBUG_m(a) \
457 if (PERL_MAYBE_ALIVE && PERL_GET_THX) { \
459 if (DEBUG_m_TEST) { \
460 PL_debug &= ~DEBUG_m_FLAG; \
462 PL_debug |= DEBUG_m_FLAG; \
468 #ifdef PERL_IMPLICIT_CONTEXT
469 # define PERL_IS_ALIVE aTHX
471 # define PERL_IS_ALIVE TRUE
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.)
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.
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.
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.
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
501 * Management of last_op:
502 * ~~~~~~~~~~~~~~~~~~~~~
504 * free() never changes the boundaries of blocks, so is not relevant.
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.
511 * malloc() may change blocks by calling morecore() only.
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();
522 * getpages() creates a new block. It marks last_op at the bottom of
523 * the chunk of memory it returns.
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.
534 * get_from_bigger_buckets(): forget to increment price => Quite
538 /* I don't much care whether these are defined in sys/types.h--LAW */
540 #define u_char unsigned char
541 #define u_int unsigned int
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
547 #define u_short unsigned short
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)
555 * The description below is applicable if PACK_MALLOC is not defined.
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.
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 */
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
579 u_char ovu_index; /* bucket # */
580 u_char ovu_magic; /* magic number */
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 */
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
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 */
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 */
602 # define MAX_SHORT_BUCKET (13 * BUCKETS_PER_POW2)
608 #if !defined(PACK_MALLOC) && defined(BUCKETS_ROOT2)
609 # undef BUCKETS_ROOT2
613 # define BUCKET_TABLE_SHIFT 2
614 # define BUCKET_POW2_SHIFT 1
615 # define BUCKETS_PER_POW2 2
617 # define BUCKET_TABLE_SHIFT MIN_BUC_POW2
618 # define BUCKET_POW2_SHIFT 0
619 # define BUCKETS_PER_POW2 1
622 #if !defined(MEM_ALIGNBYTES) || ((MEM_ALIGNBYTES > 4) && !defined(STRICT_ALIGNMENT))
623 /* Figure out the alignment of void*. */
628 # define ALIGN_SMALL ((int)((caddr_t)&(((struct aligner*)0)->p)))
630 # define ALIGN_SMALL MEM_ALIGNBYTES
633 #define IF_ALIGN_8(yes,no) ((ALIGN_SMALL>4) ? (yes) : (no))
636 # define MAX_BUCKET_BY_TABLE 13
637 static u_short buck_size[MAX_BUCKET_BY_TABLE + 1] =
639 0, 0, 0, 0, 4, 4, 8, 12, 16, 24, 32, 48, 64, 80,
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 \
644 : ((1 << ((i) >> BUCKET_POW2_SHIFT)) \
646 + POW2_OPTIMIZE_SURPLUS(i)))
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))
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.
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
663 * # One chunk only, chunksize 2^k + SOMETHING - ALIGN, k >= 11
665 * INDEX MAGIC1 UNUSED CHUNK1
667 * # Multichunk with sanity checking and chunksize 2^k-ALIGN, k>7
669 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 CHUNK2 CHUNK3 ...
671 * # Multichunk with sanity checking and size 2^k-ALIGN, k=7
673 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 UNUSED CHUNK2 CHUNK3 ...
675 * # Multichunk with sanity checking and size up to 80
677 * INDEX UNUSED MAGIC1 UNUSED MAGIC2 UNUSED ... CHUNK1 CHUNK2 CHUNK3 ...
679 * # No sanity check (usually up to 48=byte-long buckets)
680 * INDEX UNUSED CHUNK1 CHUNK2 ...
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
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.
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.]
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.
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.
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) +
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.
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.
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.]
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).
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.)
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
755 * The algo of OV_MAGIC(block,bucket) keeps ADDOFFSET 0 until
756 * chunksize of 64, then makes it 1.
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. */
787 # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2) /* Shift 128 greater than chunk 32. */
789 # define CHUNK_SHIFT 0
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) \
798 # define N_BLKS(bucket) n_blks[bucket]
801 static u_short n_blks[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
803 # if BUCKETS_PER_POW2==1
805 (MIN_BUC_POW2==2 ? 384 : 0),
806 224, 120, 62, 31, 16, 8, 4, 2
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
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)) \
821 # define BLK_SHIFT(bucket) blk_shift[bucket]
824 static u_short blk_shift[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
826 # if BUCKETS_PER_POW2==1
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),
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),
845 # define NEEDED_ALIGNMENT 0x800 /* 2k boundaries */
846 # define WANTED_ALIGNMENT 0x800 /* 2k boundaries */
848 #else /* !PACK_MALLOC */
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 */
857 #endif /* !PACK_MALLOC */
859 #define M_OVERHEAD (sizeof(union overhead) + RMAGIC_SZ) /* overhead at start+end */
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
870 # define SIZE_TABLE_MAX 64
872 static char bucket_of[] =
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 */
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),
892 # endif /* !BUCKETS_ROOT2 */
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
903 # define START_SHIFTS_BUCKET MIN_BUCKET
904 # define START_SHIFT (MIN_BUC_POW2 - 1)
905 #endif /* !PACK_MALLOC */
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.
912 #ifdef TWO_POT_OPTIMIZE
914 # ifndef PERL_PAGESIZE
915 # define PERL_PAGESIZE 4096
917 # ifndef FIRST_BIG_POW2
918 # define FIRST_BIG_POW2 15 /* 32K, 16K is used too often. */
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)
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)
931 #else /* !TWO_POT_OPTIMIZE */
932 # define POW2_OPTIMIZE_ADJUST(nbytes)
933 # define POW2_OPTIMIZE_SURPLUS(bucket) 0
934 #endif /* !TWO_POT_OPTIMIZE */
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); \
943 #else /* !HAS_64K_LIMIT || !PERL_CORE */
944 # define BARK_64K_LIMIT(what,nbytes,size)
945 #endif /* !HAS_64K_LIMIT || !PERL_CORE */
948 # define MIN_SBRK 2048
952 # define FIRST_SBRK (48*1024)
955 /* Minimal sbrk in percents of what is already alloced. */
956 #ifndef MIN_SBRK_FRAC
957 # define MIN_SBRK_FRAC 3
960 #ifndef SBRK_ALLOW_FAILURES
961 # define SBRK_ALLOW_FAILURES 3
964 #ifndef SBRK_FAILURE_PRICE
965 # define SBRK_FAILURE_PRICE 50
968 static void morecore (register int bucket);
969 # if defined(DEBUGGING)
970 static void botch (char *diag, char *s, char *file, int line);
972 static void add_to_chain (void *p, MEM_SIZE size, MEM_SIZE chip);
973 static void* get_from_chain (MEM_SIZE size);
974 static void* get_from_bigger_buckets(int bucket, MEM_SIZE size);
975 static union overhead *getpages (MEM_SIZE needed, int *nblksp, int bucket);
976 static int getpages_adjacent(MEM_SIZE require);
980 #ifdef I_MACH_CTHREADS
982 # define MUTEX_LOCK(m) STMT_START { if (*m) mutex_lock(*m); } STMT_END
984 # define MUTEX_UNLOCK(m) STMT_START { if (*m) mutex_unlock(*m); } STMT_END
987 #endif /* defined PERL_CORE */
990 # define PTRSIZE sizeof(void*)
994 # define BITS_IN_PTR (8*PTRSIZE)
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.
1002 #define NBUCKETS (BITS_IN_PTR*BUCKETS_PER_POW2 + 1)
1003 static union overhead *nextf[NBUCKETS];
1005 #if defined(PURIFY) && !defined(USE_PERL_SBRK)
1006 # define USE_PERL_SBRK
1009 #ifdef USE_PERL_SBRK
1010 # define sbrk(a) Perl_sbrk(a)
1011 Malloc_t Perl_sbrk (int size);
1013 # ifndef HAS_SBRK_PROTO /* <unistd.h> usually takes care of this */
1014 extern Malloc_t sbrk(int);
1018 #ifndef MIN_SBRK_FRAC1000 /* Backward compatibility */
1019 # define MIN_SBRK_FRAC1000 (MIN_SBRK_FRAC * 10)
1022 #ifndef START_EXTERN_C
1024 # define START_EXTERN_C extern "C" {
1026 # define START_EXTERN_C
1030 #ifndef END_EXTERN_C
1032 # define END_EXTERN_C };
1034 # define END_EXTERN_C
1038 #include "malloc_ctl.h"
1040 #ifndef NO_MALLOC_DYNAMIC_CFG
1041 # define PERL_MALLOC_OPT_CHARS "FMfAPGdac"
1043 # ifndef FILL_DEAD_DEFAULT
1044 # define FILL_DEAD_DEFAULT 1
1046 # ifndef FILL_ALIVE_DEFAULT
1047 # define FILL_ALIVE_DEFAULT 1
1049 # ifndef FILL_CHECK_DEFAULT
1050 # define FILL_CHECK_DEFAULT 1
1053 static IV MallocCfg[MallocCfg_last] = {
1057 SBRK_ALLOW_FAILURES,
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 */
1069 IV *MallocCfg_ptr = MallocCfg;
1073 # undef MIN_SBRK_FRAC1000
1074 # undef SBRK_ALLOW_FAILURES
1075 # undef SBRK_FAILURE_PRICE
1077 # define MIN_SBRK MallocCfg[MallocCfg_MIN_SBRK]
1078 # define FIRST_SBRK MallocCfg[MallocCfg_FIRST_SBRK]
1079 # define MIN_SBRK_FRAC1000 MallocCfg[MallocCfg_MIN_SBRK_FRAC1000]
1080 # define SBRK_ALLOW_FAILURES MallocCfg[MallocCfg_SBRK_ALLOW_FAILURES]
1081 # define SBRK_FAILURE_PRICE MallocCfg[MallocCfg_SBRK_FAILURE_PRICE]
1083 # define sbrk_goodness MallocCfg[MallocCfg_sbrk_goodness]
1085 # define emergency_buffer_size MallocCfg[MallocCfg_emergency_buffer_size]
1086 # define emergency_buffer_last_req MallocCfg[MallocCfg_emergency_buffer_last_req]
1088 # define FILL_DEAD MallocCfg[MallocCfg_filldead]
1089 # define FILL_ALIVE MallocCfg[MallocCfg_fillalive]
1090 # define FILL_CHECK_CFG MallocCfg[MallocCfg_fillcheck]
1091 # define FILL_CHECK (FILL_DEAD && FILL_CHECK_CFG)
1093 #else /* defined(NO_MALLOC_DYNAMIC_CFG) */
1095 # define FILL_DEAD 1
1096 # define FILL_ALIVE 1
1097 # define FILL_CHECK 1
1098 static int sbrk_goodness = SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE;
1100 # define NO_PERL_MALLOC_ENV
1104 #ifdef DEBUGGING_MSTATS
1106 * nmalloc[i] is the difference between the number of mallocs and frees
1107 * for a given block size.
1109 static u_int nmalloc[NBUCKETS];
1110 static u_int sbrk_slack;
1111 static u_int start_slack;
1112 #else /* !( defined DEBUGGING_MSTATS ) */
1113 # define sbrk_slack 0
1116 static u_int goodsbrk;
1118 #ifdef PERL_EMERGENCY_SBRK
1121 # define BIG_SIZE (1<<16) /* 64K */
1124 static char *emergency_buffer;
1125 static char *emergency_buffer_prepared;
1127 # ifdef NO_MALLOC_DYNAMIC_CFG
1128 static MEM_SIZE emergency_buffer_size;
1129 /* 0 if the last request for more memory succeeded.
1130 Otherwise the size of the failing request. */
1131 static MEM_SIZE emergency_buffer_last_req;
1134 # ifndef emergency_sbrk_croak
1135 # define emergency_sbrk_croak croak2
1140 perl_get_emergency_buffer(IV *size)
1143 /* First offense, give a possibility to recover by dieing. */
1144 /* No malloc involved here: */
1145 GV **gvp = (GV**)hv_fetch(PL_defstash, "^M", 2, 0);
1150 if (!gvp) gvp = (GV**)hv_fetch(PL_defstash, "\015", 1, 0);
1151 if (!gvp || !(sv = GvSV(*gvp)) || !SvPOK(sv)
1152 || (SvLEN(sv) < (1<<LOG_OF_MIN_ARENA) - M_OVERHEAD))
1153 return NULL; /* Now die die die... */
1154 /* Got it, now detach SvPV: */
1156 /* Check alignment: */
1157 if ((PTR2UV(pv) - sizeof(union overhead)) & (NEEDED_ALIGNMENT - 1)) {
1158 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
1159 return NULL; /* die die die */
1164 SvCUR(sv) = SvLEN(sv) = 0;
1165 *size = malloced_size(pv) + M_OVERHEAD;
1166 return pv - sizeof(union overhead);
1168 # define PERL_GET_EMERGENCY_BUFFER(p) perl_get_emergency_buffer(p)
1170 # define PERL_GET_EMERGENCY_BUFFER(p) NULL
1171 # endif /* defined PERL_CORE */
1173 # ifndef NO_MALLOC_DYNAMIC_CFG
1175 get_emergency_buffer(IV *size)
1177 char *pv = emergency_buffer_prepared;
1179 *size = MallocCfg[MallocCfg_emergency_buffer_prepared_size];
1180 emergency_buffer_prepared = 0;
1181 MallocCfg[MallocCfg_emergency_buffer_prepared_size] = 0;
1185 /* Returns 0 on success, -1 on bad alignment, -2 if not implemented */
1187 set_emergency_buffer(char *b, IV size)
1189 if (PTR2UV(b) & (NEEDED_ALIGNMENT - 1))
1191 if (MallocCfg[MallocCfg_emergency_buffer_prepared_size])
1192 add_to_chain((void*)emergency_buffer_prepared,
1193 MallocCfg[MallocCfg_emergency_buffer_prepared_size], 0);
1194 emergency_buffer_prepared = b;
1195 MallocCfg[MallocCfg_emergency_buffer_prepared_size] = size;
1198 # define GET_EMERGENCY_BUFFER(p) get_emergency_buffer(p)
1199 # else /* NO_MALLOC_DYNAMIC_CFG */
1200 # define GET_EMERGENCY_BUFFER(p) NULL
1202 set_emergency_buffer(char *b, IV size)
1209 emergency_sbrk(MEM_SIZE size)
1211 MEM_SIZE rsize = (((size - 1)>>LOG_OF_MIN_ARENA) + 1)<<LOG_OF_MIN_ARENA;
1213 if (size >= BIG_SIZE
1214 && (!emergency_buffer_last_req || (size < emergency_buffer_last_req))) {
1215 /* Give the possibility to recover, but avoid an infinite cycle. */
1217 emergency_buffer_last_req = size;
1218 emergency_sbrk_croak("Out of memory during \"large\" request for %"UVuf" bytes, total sbrk() is %"UVuf" bytes", (UV)size, (UV)(goodsbrk + sbrk_slack));
1221 if (emergency_buffer_size >= rsize) {
1222 char *old = emergency_buffer;
1224 emergency_buffer_size -= rsize;
1225 emergency_buffer += rsize;
1228 /* First offense, give a possibility to recover by dieing. */
1229 /* No malloc involved here: */
1231 char *pv = GET_EMERGENCY_BUFFER(&Size);
1234 if (emergency_buffer_size) {
1235 add_to_chain(emergency_buffer, emergency_buffer_size, 0);
1236 emergency_buffer_size = 0;
1237 emergency_buffer = Nullch;
1242 pv = PERL_GET_EMERGENCY_BUFFER(&Size);
1246 return (char *)-1; /* Now die die die... */
1249 /* Check alignment: */
1250 if (PTR2UV(pv) & (NEEDED_ALIGNMENT - 1)) {
1253 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
1254 return (char *)-1; /* die die die */
1257 emergency_buffer = pv;
1258 emergency_buffer_size = Size;
1262 emergency_sbrk_croak("Out of memory during request for %"UVuf" bytes, total sbrk() is %"UVuf" bytes", (UV)size, (UV)(goodsbrk + sbrk_slack));
1267 #else /* !defined(PERL_EMERGENCY_SBRK) */
1268 # define emergency_sbrk(size) -1
1269 #endif /* defined PERL_EMERGENCY_SBRK */
1274 write(2, mess, strlen(mess));
1279 #define ASSERT(p,diag) if (!(p)) botch(diag,STRINGIFY(p),__FILE__,__LINE__); else
1281 botch(char *diag, char *s, char *file, int line)
1283 if (!(PERL_MAYBE_ALIVE && PERL_GET_THX))
1287 if (PerlIO_printf(PerlIO_stderr(),
1288 "assertion botched (%s?): %s %s:%d\n",
1289 diag, s, file, line) != 0) {
1290 do_write: /* Can be initializing interpreter */
1291 write2("assertion botched (");
1300 char *s = linebuf + sizeof(linebuf) - 1;
1304 *--s = '0' + (n % 10);
1314 #define ASSERT(p, diag)
1318 /* Fill should be long enough to cover long */
1320 fill_pat_4bytes(unsigned char *s, size_t nbytes, const unsigned char *fill)
1322 unsigned char *e = s + nbytes;
1324 long lfill = *(long*)fill;
1326 if (PTR2UV(s) & (sizeof(long)-1)) { /* Align the pattern */
1327 int shift = sizeof(long) - (PTR2UV(s) & (sizeof(long)-1));
1328 unsigned const char *f = fill + sizeof(long) - shift;
1329 unsigned char *e1 = s + shift;
1335 while ((unsigned char*)(lp + 1) <= e)
1337 s = (unsigned char*)lp;
1341 /* Just malloc()ed */
1342 static const unsigned char fill_feedadad[] =
1343 {0xFE, 0xED, 0xAD, 0xAD, 0xFE, 0xED, 0xAD, 0xAD,
1344 0xFE, 0xED, 0xAD, 0xAD, 0xFE, 0xED, 0xAD, 0xAD};
1346 static const unsigned char fill_deadbeef[] =
1347 {0xDE, 0xAD, 0xBE, 0xEF, 0xDE, 0xAD, 0xBE, 0xEF,
1348 0xDE, 0xAD, 0xBE, 0xEF, 0xDE, 0xAD, 0xBE, 0xEF};
1349 # define FILL_DEADBEEF(s, n) \
1350 (void)(FILL_DEAD? (fill_pat_4bytes((s), (n), fill_deadbeef), 0) : 0)
1351 # define FILL_FEEDADAD(s, n) \
1352 (void)(FILL_ALIVE? (fill_pat_4bytes((s), (n), fill_feedadad), 0) : 0)
1354 # define FILL_DEADBEEF(s, n) ((void)0)
1355 # define FILL_FEEDADAD(s, n) ((void)0)
1356 # undef MALLOC_FILL_CHECK
1359 #ifdef MALLOC_FILL_CHECK
1361 cmp_pat_4bytes(unsigned char *s, size_t nbytes, const unsigned char *fill)
1363 unsigned char *e = s + nbytes;
1365 long lfill = *(long*)fill;
1367 if (PTR2UV(s) & (sizeof(long)-1)) { /* Align the pattern */
1368 int shift = sizeof(long) - (PTR2UV(s) & (sizeof(long)-1));
1369 unsigned const char *f = fill + sizeof(long) - shift;
1370 unsigned char *e1 = s + shift;
1377 while ((unsigned char*)(lp + 1) <= e)
1380 s = (unsigned char*)lp;
1382 if (*s++ != *fill++)
1386 # define FILLCHECK_DEADBEEF(s, n) \
1387 ASSERT(!FILL_CHECK || !cmp_pat_4bytes(s, n, fill_deadbeef), \
1388 "free()ed/realloc()ed-away memory was overwritten")
1390 # define FILLCHECK_DEADBEEF(s, n) ((void)0)
1394 Perl_malloc(register size_t nbytes)
1396 register union overhead *p;
1397 register int bucket;
1398 register MEM_SIZE shiftr;
1400 #if defined(DEBUGGING) || defined(RCHECK)
1401 MEM_SIZE size = nbytes;
1404 BARK_64K_LIMIT("Allocation",nbytes,nbytes);
1406 if ((long)nbytes < 0)
1407 croak("%s", "panic: malloc");
1411 * Convert amount of memory requested into
1412 * closest block size stored in hash buckets
1413 * which satisfies request. Account for
1414 * space used per block for accounting.
1417 # ifdef SMALL_BUCKET_VIA_TABLE
1419 bucket = MIN_BUCKET;
1420 else if (nbytes <= SIZE_TABLE_MAX) {
1421 bucket = bucket_of[(nbytes - 1) >> BUCKET_TABLE_SHIFT];
1426 if (nbytes <= MAX_POW2_ALGO) goto do_shifts;
1431 POW2_OPTIMIZE_ADJUST(nbytes);
1432 nbytes += M_OVERHEAD;
1433 nbytes = (nbytes + 3) &~ 3;
1434 #if defined(PACK_MALLOC) && !defined(SMALL_BUCKET_VIA_TABLE)
1437 shiftr = (nbytes - 1) >> START_SHIFT;
1438 bucket = START_SHIFTS_BUCKET;
1439 /* apart from this loop, this is O(1) */
1440 while (shiftr >>= 1)
1441 bucket += BUCKETS_PER_POW2;
1445 * If nothing in hash bucket right now,
1446 * request more memory from the system.
1448 if (nextf[bucket] == NULL)
1450 if ((p = nextf[bucket]) == NULL) {
1456 #if defined(PLAIN_MALLOC) && defined(NO_FANCY_MALLOC)
1457 PerlIO_puts(PerlIO_stderr(),"Out of memory!\n");
1460 char *eb = buff + sizeof(buff) - 1;
1464 PerlIO_puts(PerlIO_stderr(),"Out of memory during request for ");
1465 #if defined(DEBUGGING) || defined(RCHECK)
1470 *--s = '0' + (n % 10);
1472 PerlIO_puts(PerlIO_stderr(),s);
1473 PerlIO_puts(PerlIO_stderr()," bytes, total sbrk() is ");
1475 n = goodsbrk + sbrk_slack;
1477 *--s = '0' + (n % 10);
1479 PerlIO_puts(PerlIO_stderr(),s);
1480 PerlIO_puts(PerlIO_stderr()," bytes!\n");
1481 #endif /* defined(PLAIN_MALLOC) && defined(NO_FANCY_MALLOC) */
1489 /* remove from linked list */
1491 if ( (PTR2UV(p) & (MEM_ALIGNBYTES - 1))
1492 /* Can't get this low */
1493 || (p && PTR2UV(p) < (1<<LOG_OF_MIN_ARENA)) ) {
1495 PerlIO_printf(PerlIO_stderr(),
1496 "Unaligned pointer in the free chain 0x%"UVxf"\n",
1499 if ( (PTR2UV(p->ov_next) & (MEM_ALIGNBYTES - 1))
1500 || (p->ov_next && PTR2UV(p->ov_next) < (1<<LOG_OF_MIN_ARENA)) ) {
1502 PerlIO_printf(PerlIO_stderr(),
1503 "Unaligned `next' pointer in the free "
1504 "chain 0x%"UVxf" at 0x%"UVxf"\n",
1505 PTR2UV(p->ov_next), PTR2UV(p));
1508 nextf[bucket] = p->ov_next;
1512 DEBUG_m(PerlIO_printf(Perl_debug_log,
1513 "0x%"UVxf": (%05lu) malloc %ld bytes\n",
1514 PTR2UV((Malloc_t)(p + CHUNK_SHIFT)), (unsigned long)(PL_an++),
1517 FILLCHECK_DEADBEEF((unsigned char*)(p + CHUNK_SHIFT),
1518 BUCKET_SIZE_REAL(bucket) + RMAGIC_SZ);
1520 #ifdef IGNORE_SMALL_BAD_FREE
1521 if (bucket >= FIRST_BUCKET_WITH_CHECK)
1523 OV_MAGIC(p, bucket) = MAGIC;
1525 OV_INDEX(p) = bucket;
1529 * Record allocated size of block and
1530 * bound space with magic numbers.
1532 p->ov_rmagic = RMAGIC;
1533 if (bucket <= MAX_SHORT_BUCKET) {
1536 nbytes = size + M_OVERHEAD;
1537 p->ov_size = nbytes - 1;
1538 if ((i = nbytes & (RMAGIC_SZ-1))) {
1540 while (i--) /* nbytes - RMAGIC_SZ is end of alloced area */
1541 ((caddr_t)p + nbytes - RMAGIC_SZ)[i] = RMAGIC_C;
1543 /* Same at RMAGIC_SZ-aligned RMAGIC */
1544 nbytes = (nbytes + RMAGIC_SZ - 1) & ~(RMAGIC_SZ - 1);
1545 ((u_int *)((caddr_t)p + nbytes))[-1] = RMAGIC;
1547 FILL_FEEDADAD((unsigned char *)(p + CHUNK_SHIFT), size);
1549 return ((Malloc_t)(p + CHUNK_SHIFT));
1552 static char *last_sbrk_top;
1553 static char *last_op; /* This arena can be easily extended. */
1554 static MEM_SIZE sbrked_remains;
1556 #ifdef DEBUGGING_MSTATS
1560 struct chunk_chain_s {
1561 struct chunk_chain_s *next;
1564 static struct chunk_chain_s *chunk_chain;
1565 static int n_chunks;
1566 static char max_bucket;
1568 /* Cutoff a piece of one of the chunks in the chain. Prefer smaller chunk. */
1570 get_from_chain(MEM_SIZE size)
1572 struct chunk_chain_s *elt = chunk_chain, **oldp = &chunk_chain;
1573 struct chunk_chain_s **oldgoodp = NULL;
1574 long min_remain = LONG_MAX;
1577 if (elt->size >= size) {
1578 long remains = elt->size - size;
1579 if (remains >= 0 && remains < min_remain) {
1581 min_remain = remains;
1587 oldp = &( elt->next );
1590 if (!oldgoodp) return NULL;
1592 void *ret = *oldgoodp;
1593 struct chunk_chain_s *next = (*oldgoodp)->next;
1595 *oldgoodp = (struct chunk_chain_s *)((char*)ret + size);
1596 (*oldgoodp)->size = min_remain;
1597 (*oldgoodp)->next = next;
1600 void *ret = *oldgoodp;
1601 *oldgoodp = (*oldgoodp)->next;
1608 add_to_chain(void *p, MEM_SIZE size, MEM_SIZE chip)
1610 struct chunk_chain_s *next = chunk_chain;
1611 char *cp = (char*)p;
1614 chunk_chain = (struct chunk_chain_s *)cp;
1615 chunk_chain->size = size - chip;
1616 chunk_chain->next = next;
1621 get_from_bigger_buckets(int bucket, MEM_SIZE size)
1624 static int bucketprice[NBUCKETS];
1625 while (bucket <= max_bucket) {
1626 /* We postpone stealing from bigger buckets until we want it
1628 if (nextf[bucket] && bucketprice[bucket]++ >= price) {
1630 void *ret = (void*)(nextf[bucket] - 1 + CHUNK_SHIFT);
1631 bucketprice[bucket] = 0;
1632 if (((char*)nextf[bucket]) - M_OVERHEAD == last_op) {
1633 last_op = NULL; /* Disable optimization */
1635 nextf[bucket] = nextf[bucket]->ov_next;
1636 #ifdef DEBUGGING_MSTATS
1638 start_slack -= M_OVERHEAD;
1640 add_to_chain(ret, (BUCKET_SIZE_NO_SURPLUS(bucket) +
1641 POW2_OPTIMIZE_SURPLUS(bucket)),
1650 static union overhead *
1651 getpages(MEM_SIZE needed, int *nblksp, int bucket)
1653 /* Need to do (possibly expensive) system call. Try to
1654 optimize it for rare calling. */
1655 MEM_SIZE require = needed - sbrked_remains;
1657 union overhead *ovp;
1660 if (sbrk_goodness > 0) {
1661 if (!last_sbrk_top && require < FIRST_SBRK)
1662 require = FIRST_SBRK;
1663 else if (require < MIN_SBRK) require = MIN_SBRK;
1665 if (require < goodsbrk * MIN_SBRK_FRAC1000 / 1000)
1666 require = goodsbrk * MIN_SBRK_FRAC1000 / 1000;
1667 require = ((require - 1 + MIN_SBRK) / MIN_SBRK) * MIN_SBRK;
1674 DEBUG_m(PerlIO_printf(Perl_debug_log,
1675 "sbrk(%ld) for %ld-byte-long arena\n",
1676 (long)require, (long) needed));
1677 cp = (char *)sbrk(require);
1678 #ifdef DEBUGGING_MSTATS
1681 if (cp == last_sbrk_top) {
1682 /* Common case, anything is fine. */
1684 ovp = (union overhead *) (cp - sbrked_remains);
1685 last_op = cp - sbrked_remains;
1686 sbrked_remains = require - (needed - sbrked_remains);
1687 } else if (cp == (char *)-1) { /* no more room! */
1688 ovp = (union overhead *)emergency_sbrk(needed);
1689 if (ovp == (union overhead *)-1)
1691 if (((char*)ovp) > last_op) { /* Cannot happen with current emergency_sbrk() */
1695 } else { /* Non-continuous or first sbrk(). */
1696 long add = sbrked_remains;
1699 if (sbrked_remains) { /* Put rest into chain, we
1700 cannot use it right now. */
1701 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1705 /* Second, check alignment. */
1708 #if !defined(atarist) && !defined(__MINT__) /* on the atari we dont have to worry about this */
1709 # ifndef I286 /* The sbrk(0) call on the I286 always returns the next segment */
1710 /* WANTED_ALIGNMENT may be more than NEEDED_ALIGNMENT, but this may
1711 improve performance of memory access. */
1712 if (PTR2UV(cp) & (WANTED_ALIGNMENT - 1)) { /* Not aligned. */
1713 slack = WANTED_ALIGNMENT - (PTR2UV(cp) & (WANTED_ALIGNMENT - 1));
1717 #endif /* !atarist && !MINT */
1720 DEBUG_m(PerlIO_printf(Perl_debug_log,
1721 "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",
1722 (long)add, (long) slack,
1723 (long) sbrked_remains));
1724 newcp = (char *)sbrk(add);
1725 #if defined(DEBUGGING_MSTATS)
1729 if (newcp != cp + require) {
1730 /* Too bad: even rounding sbrk() is not continuous.*/
1731 DEBUG_m(PerlIO_printf(Perl_debug_log,
1732 "failed to fix bad sbrk()\n"));
1736 fatalcroak("panic: Off-page sbrk\n");
1739 if (sbrked_remains) {
1741 #if defined(DEBUGGING_MSTATS)
1742 sbrk_slack += require;
1745 DEBUG_m(PerlIO_printf(Perl_debug_log,
1746 "straight sbrk(%ld)\n",
1748 cp = (char *)sbrk(require);
1749 #ifdef DEBUGGING_MSTATS
1752 if (cp == (char *)-1)
1755 sbrk_goodness = -1; /* Disable optimization!
1756 Continue with not-aligned... */
1759 require += sbrked_remains;
1763 if (last_sbrk_top) {
1764 sbrk_goodness -= SBRK_FAILURE_PRICE;
1767 ovp = (union overhead *) cp;
1769 * Round up to minimum allocation size boundary
1770 * and deduct from block count to reflect.
1773 # if NEEDED_ALIGNMENT > MEM_ALIGNBYTES
1774 if (PTR2UV(ovp) & (NEEDED_ALIGNMENT - 1))
1775 fatalcroak("Misalignment of sbrk()\n");
1778 #ifndef I286 /* Again, this should always be ok on an 80286 */
1779 if (PTR2UV(ovp) & (MEM_ALIGNBYTES - 1)) {
1780 DEBUG_m(PerlIO_printf(Perl_debug_log,
1781 "fixing sbrk(): %d bytes off machine alignement\n",
1782 (int)(PTR2UV(ovp) & (MEM_ALIGNBYTES - 1))));
1783 ovp = INT2PTR(union overhead *,(PTR2UV(ovp) + MEM_ALIGNBYTES) &
1784 (MEM_ALIGNBYTES - 1));
1786 # if defined(DEBUGGING_MSTATS)
1787 /* This is only approx. if TWO_POT_OPTIMIZE: */
1788 sbrk_slack += (1 << (bucket >> BUCKET_POW2_SHIFT));
1792 ; /* Finish `else' */
1793 sbrked_remains = require - needed;
1796 #if !defined(PLAIN_MALLOC) && !defined(NO_FANCY_MALLOC)
1797 emergency_buffer_last_req = 0;
1799 last_sbrk_top = cp + require;
1800 #ifdef DEBUGGING_MSTATS
1801 goodsbrk += require;
1807 getpages_adjacent(MEM_SIZE require)
1809 if (require <= sbrked_remains) {
1810 sbrked_remains -= require;
1814 require -= sbrked_remains;
1815 /* We do not try to optimize sbrks here, we go for place. */
1816 cp = (char*) sbrk(require);
1817 #ifdef DEBUGGING_MSTATS
1819 goodsbrk += require;
1821 if (cp == last_sbrk_top) {
1823 last_sbrk_top = cp + require;
1825 if (cp == (char*)-1) { /* Out of memory */
1826 #ifdef DEBUGGING_MSTATS
1827 goodsbrk -= require;
1831 /* Report the failure: */
1833 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1835 add_to_chain((void*)cp, require, 0);
1836 sbrk_goodness -= SBRK_FAILURE_PRICE;
1848 * Allocate more memory to the indicated bucket.
1851 morecore(register int bucket)
1853 register union overhead *ovp;
1854 register int rnu; /* 2^rnu bytes will be requested */
1855 int nblks; /* become nblks blocks of the desired size */
1856 register MEM_SIZE siz, needed;
1857 static int were_called = 0;
1861 #ifndef NO_PERL_MALLOC_ENV
1863 /* It's the our first time. Initialize ourselves */
1864 were_called = 1; /* Avoid a loop */
1865 if (!MallocCfg[MallocCfg_skip_cfg_env]) {
1866 char *s = getenv("PERL_MALLOC_OPT"), *t = s, *off;
1867 const char *opts = PERL_MALLOC_OPT_CHARS;
1870 while ( t && t[0] && t[1] == '='
1871 && ((off = strchr(opts, *t))) ) {
1875 while (*t <= '9' && *t >= '0')
1876 val = 10*val + *t++ - '0';
1877 if (!*t || *t == ';') {
1878 if (MallocCfg[off - opts] != val)
1880 MallocCfg[off - opts] = val;
1886 write2("Unrecognized part of PERL_MALLOC_OPT: `");
1891 MallocCfg[MallocCfg_cfg_env_read] = 1;
1895 if (bucket == sizeof(MEM_SIZE)*8*BUCKETS_PER_POW2) {
1897 croak("%s", "Out of memory during ridiculously large request");
1899 if (bucket > max_bucket)
1900 max_bucket = bucket;
1902 rnu = ( (bucket <= (LOG_OF_MIN_ARENA << BUCKET_POW2_SHIFT))
1904 : (bucket >> BUCKET_POW2_SHIFT) );
1905 /* This may be overwritten later: */
1906 nblks = 1 << (rnu - (bucket >> BUCKET_POW2_SHIFT)); /* how many blocks to get */
1907 needed = ((MEM_SIZE)1 << rnu) + POW2_OPTIMIZE_SURPLUS(bucket);
1908 if (nextf[rnu << BUCKET_POW2_SHIFT]) { /* 2048b bucket. */
1909 ovp = nextf[rnu << BUCKET_POW2_SHIFT] - 1 + CHUNK_SHIFT;
1910 nextf[rnu << BUCKET_POW2_SHIFT]
1911 = nextf[rnu << BUCKET_POW2_SHIFT]->ov_next;
1912 #ifdef DEBUGGING_MSTATS
1913 nmalloc[rnu << BUCKET_POW2_SHIFT]--;
1914 start_slack -= M_OVERHEAD;
1916 DEBUG_m(PerlIO_printf(Perl_debug_log,
1917 "stealing %ld bytes from %ld arena\n",
1918 (long) needed, (long) rnu << BUCKET_POW2_SHIFT));
1919 } else if (chunk_chain
1920 && (ovp = (union overhead*) get_from_chain(needed))) {
1921 DEBUG_m(PerlIO_printf(Perl_debug_log,
1922 "stealing %ld bytes from chain\n",
1924 } else if ( (ovp = (union overhead*)
1925 get_from_bigger_buckets((rnu << BUCKET_POW2_SHIFT) + 1,
1927 DEBUG_m(PerlIO_printf(Perl_debug_log,
1928 "stealing %ld bytes from bigger buckets\n",
1930 } else if (needed <= sbrked_remains) {
1931 ovp = (union overhead *)(last_sbrk_top - sbrked_remains);
1932 sbrked_remains -= needed;
1933 last_op = (char*)ovp;
1935 ovp = getpages(needed, &nblks, bucket);
1939 FILL_DEADBEEF((unsigned char*)ovp, needed);
1942 * Add new memory allocated to that on
1943 * free list for this hash bucket.
1945 siz = BUCKET_SIZE_NO_SURPLUS(bucket); /* No surplus if nblks > 1 */
1947 *(u_char*)ovp = bucket; /* Fill index. */
1948 if (bucket <= MAX_PACKED) {
1949 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1950 nblks = N_BLKS(bucket);
1951 # ifdef DEBUGGING_MSTATS
1952 start_slack += BLK_SHIFT(bucket);
1954 } else if (bucket < LOG_OF_MIN_ARENA * BUCKETS_PER_POW2) {
1955 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1956 siz -= sizeof(union overhead);
1957 } else ovp++; /* One chunk per block. */
1958 #endif /* PACK_MALLOC */
1959 nextf[bucket] = ovp;
1960 #ifdef DEBUGGING_MSTATS
1961 nmalloc[bucket] += nblks;
1962 if (bucket > MAX_PACKED) {
1963 start_slack += M_OVERHEAD * nblks;
1967 while (--nblks > 0) {
1968 ovp->ov_next = (union overhead *)((caddr_t)ovp + siz);
1969 ovp = (union overhead *)((caddr_t)ovp + siz);
1971 /* Not all sbrks return zeroed memory.*/
1972 ovp->ov_next = (union overhead *)NULL;
1974 if (bucket == 7*BUCKETS_PER_POW2) { /* Special case, explanation is above. */
1975 union overhead *n_op = nextf[7*BUCKETS_PER_POW2]->ov_next;
1976 nextf[7*BUCKETS_PER_POW2] =
1977 (union overhead *)((caddr_t)nextf[7*BUCKETS_PER_POW2]
1978 - sizeof(union overhead));
1979 nextf[7*BUCKETS_PER_POW2]->ov_next = n_op;
1981 #endif /* !PACK_MALLOC */
1985 Perl_mfree(void *mp)
1987 register MEM_SIZE size;
1988 register union overhead *ovp;
1989 char *cp = (char*)mp;
1994 DEBUG_m(PerlIO_printf(Perl_debug_log,
1995 "0x%"UVxf": (%05lu) free\n",
1996 PTR2UV(cp), (unsigned long)(PL_an++)));
2001 if (PTR2UV(cp) & (MEM_ALIGNBYTES - 1))
2002 croak("%s", "wrong alignment in free()");
2004 ovp = (union overhead *)((caddr_t)cp
2005 - sizeof (union overhead) * CHUNK_SHIFT);
2007 bucket = OV_INDEX(ovp);
2009 #ifdef IGNORE_SMALL_BAD_FREE
2010 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
2011 && (OV_MAGIC(ovp, bucket) != MAGIC))
2013 if (OV_MAGIC(ovp, bucket) != MAGIC)
2016 static int bad_free_warn = -1;
2017 if (bad_free_warn == -1) {
2019 char *pbf = PerlEnv_getenv("PERL_BADFREE");
2020 bad_free_warn = (pbf) ? atoi(pbf) : 1;
2028 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
2029 Perl_warner(aTHX_ packWARN(WARN_MALLOC), "%s free() ignored (RMAGIC, PERL_CORE)",
2030 ovp->ov_rmagic == RMAGIC - 1 ?
2031 "Duplicate" : "Bad");
2034 warn("%s free() ignored (RMAGIC)",
2035 ovp->ov_rmagic == RMAGIC - 1 ? "Duplicate" : "Bad");
2041 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
2042 Perl_warner(aTHX_ packWARN(WARN_MALLOC), "%s", "Bad free() ignored (PERL_CORE)");
2045 warn("%s", "Bad free() ignored");
2048 return; /* sanity */
2051 ASSERT(ovp->ov_rmagic == RMAGIC, "chunk's head overwrite");
2052 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
2054 MEM_SIZE nbytes = ovp->ov_size + 1;
2056 if ((i = nbytes & (RMAGIC_SZ-1))) {
2058 while (i--) { /* nbytes - RMAGIC_SZ is end of alloced area */
2059 ASSERT(((caddr_t)ovp + nbytes - RMAGIC_SZ)[i] == RMAGIC_C,
2060 "chunk's tail overwrite");
2063 /* Same at RMAGIC_SZ-aligned RMAGIC */
2064 nbytes = (nbytes + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ-1);
2065 ASSERT(((u_int *)((caddr_t)ovp + nbytes))[-1] == RMAGIC,
2066 "chunk's tail overwrite");
2067 FILLCHECK_DEADBEEF((unsigned char*)((caddr_t)ovp + nbytes),
2068 BUCKET_SIZE(OV_INDEX(ovp)) - nbytes);
2070 FILL_DEADBEEF((unsigned char*)(ovp+CHUNK_SHIFT),
2071 BUCKET_SIZE_REAL(OV_INDEX(ovp)) + RMAGIC_SZ);
2072 ovp->ov_rmagic = RMAGIC - 1;
2074 ASSERT(OV_INDEX(ovp) < NBUCKETS, "chunk's head overwrite");
2075 size = OV_INDEX(ovp);
2078 ovp->ov_next = nextf[size];
2083 /* There is no need to do any locking in realloc (with an exception of
2084 trying to grow in place if we are at the end of the chain).
2085 If somebody calls us from a different thread with the same address,
2086 we are sole anyway. */
2089 Perl_realloc(void *mp, size_t nbytes)
2091 register MEM_SIZE onb;
2092 union overhead *ovp;
2095 register int bucket;
2096 int incr; /* 1 if does not fit, -1 if "easily" fits in a
2097 smaller bucket, otherwise 0. */
2098 char *cp = (char*)mp;
2100 #if defined(DEBUGGING) || !defined(PERL_CORE)
2101 MEM_SIZE size = nbytes;
2103 if ((long)nbytes < 0)
2104 croak("%s", "panic: realloc");
2107 BARK_64K_LIMIT("Reallocation",nbytes,size);
2109 return Perl_malloc(nbytes);
2111 ovp = (union overhead *)((caddr_t)cp
2112 - sizeof (union overhead) * CHUNK_SHIFT);
2113 bucket = OV_INDEX(ovp);
2115 #ifdef IGNORE_SMALL_BAD_FREE
2116 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
2117 && (OV_MAGIC(ovp, bucket) != MAGIC))
2119 if (OV_MAGIC(ovp, bucket) != MAGIC)
2122 static int bad_free_warn = -1;
2123 if (bad_free_warn == -1) {
2125 char *pbf = PerlEnv_getenv("PERL_BADFREE");
2126 bad_free_warn = (pbf) ? atoi(pbf) : 1;
2134 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
2135 Perl_warner(aTHX_ packWARN(WARN_MALLOC), "%srealloc() %signored",
2136 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
2137 ovp->ov_rmagic == RMAGIC - 1
2138 ? "of freed memory " : "");
2141 warn2("%srealloc() %signored",
2142 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
2143 ovp->ov_rmagic == RMAGIC - 1 ? "of freed memory " : "");
2149 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
2150 Perl_warner(aTHX_ packWARN(WARN_MALLOC), "%s",
2151 "Bad realloc() ignored");
2154 warn("%s", "Bad realloc() ignored");
2157 return Nullch; /* sanity */
2160 onb = BUCKET_SIZE_REAL(bucket);
2162 * avoid the copy if same size block.
2163 * We are not agressive with boundary cases. Note that it might
2164 * (for a small number of cases) give false negative if
2165 * both new size and old one are in the bucket for
2166 * FIRST_BIG_POW2, but the new one is near the lower end.
2168 * We do not try to go to 1.5 times smaller bucket so far.
2170 if (nbytes > onb) incr = 1;
2172 #ifdef DO_NOT_TRY_HARDER_WHEN_SHRINKING
2173 if ( /* This is a little bit pessimal if PACK_MALLOC: */
2174 nbytes > ( (onb >> 1) - M_OVERHEAD )
2175 # ifdef TWO_POT_OPTIMIZE
2176 || (bucket == FIRST_BIG_POW2 && nbytes >= LAST_SMALL_BOUND )
2179 #else /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
2180 prev_bucket = ( (bucket > MAX_PACKED + 1)
2181 ? bucket - BUCKETS_PER_POW2
2183 if (nbytes > BUCKET_SIZE_REAL(prev_bucket))
2184 #endif /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
2188 #ifdef STRESS_REALLOC
2195 * Record new allocated size of block and
2196 * bound space with magic numbers.
2198 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
2199 int i, nb = ovp->ov_size + 1;
2201 if ((i = nb & (RMAGIC_SZ-1))) {
2203 while (i--) { /* nb - RMAGIC_SZ is end of alloced area */
2204 ASSERT(((caddr_t)ovp + nb - RMAGIC_SZ)[i] == RMAGIC_C, "chunk's tail overwrite");
2207 /* Same at RMAGIC_SZ-aligned RMAGIC */
2208 nb = (nb + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ-1);
2209 ASSERT(((u_int *)((caddr_t)ovp + nb))[-1] == RMAGIC,
2210 "chunk's tail overwrite");
2211 FILLCHECK_DEADBEEF((unsigned char*)((caddr_t)ovp + nb),
2212 BUCKET_SIZE(OV_INDEX(ovp)) - nb);
2213 if (nbytes > ovp->ov_size + 1 - M_OVERHEAD)
2214 FILL_FEEDADAD((unsigned char*)cp + ovp->ov_size + 1 - M_OVERHEAD,
2215 nbytes - (ovp->ov_size + 1 - M_OVERHEAD));
2217 FILL_DEADBEEF((unsigned char*)cp + nbytes,
2218 nb - M_OVERHEAD + RMAGIC_SZ - nbytes);
2220 * Convert amount of memory requested into
2221 * closest block size stored in hash buckets
2222 * which satisfies request. Account for
2223 * space used per block for accounting.
2225 nbytes += M_OVERHEAD;
2226 ovp->ov_size = nbytes - 1;
2227 if ((i = nbytes & (RMAGIC_SZ-1))) {
2229 while (i--) /* nbytes - RMAGIC_SZ is end of alloced area */
2230 ((caddr_t)ovp + nbytes - RMAGIC_SZ)[i]
2233 /* Same at RMAGIC_SZ-aligned RMAGIC */
2234 nbytes = (nbytes + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ - 1);
2235 ((u_int *)((caddr_t)ovp + nbytes))[-1] = RMAGIC;
2239 DEBUG_m(PerlIO_printf(Perl_debug_log,
2240 "0x%"UVxf": (%05lu) realloc %ld bytes inplace\n",
2241 PTR2UV(res),(unsigned long)(PL_an++),
2243 } else if (incr == 1 && (cp - M_OVERHEAD == last_op)
2244 && (onb > (1 << LOG_OF_MIN_ARENA))) {
2245 MEM_SIZE require, newarena = nbytes, pow;
2248 POW2_OPTIMIZE_ADJUST(newarena);
2249 newarena = newarena + M_OVERHEAD;
2250 /* newarena = (newarena + 3) &~ 3; */
2251 shiftr = (newarena - 1) >> LOG_OF_MIN_ARENA;
2252 pow = LOG_OF_MIN_ARENA + 1;
2253 /* apart from this loop, this is O(1) */
2254 while (shiftr >>= 1)
2256 newarena = (1 << pow) + POW2_OPTIMIZE_SURPLUS(pow * BUCKETS_PER_POW2);
2257 require = newarena - onb - M_OVERHEAD;
2260 if (cp - M_OVERHEAD == last_op /* We *still* are the last chunk */
2261 && getpages_adjacent(require)) {
2262 #ifdef DEBUGGING_MSTATS
2264 nmalloc[pow * BUCKETS_PER_POW2]++;
2266 *(cp - M_OVERHEAD) = pow * BUCKETS_PER_POW2; /* Fill index. */
2275 DEBUG_m(PerlIO_printf(Perl_debug_log,
2276 "0x%"UVxf": (%05lu) realloc %ld bytes the hard way\n",
2277 PTR2UV(cp),(unsigned long)(PL_an++),
2279 if ((res = (char*)Perl_malloc(nbytes)) == NULL)
2281 if (cp != res) /* common optimization */
2282 Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char);
2285 return ((Malloc_t)res);
2289 Perl_calloc(register size_t elements, register size_t size)
2291 long sz = elements * size;
2292 Malloc_t p = Perl_malloc(sz);
2295 memset((void*)p, 0, sz);
2301 Perl_strdup(const char *s)
2303 MEM_SIZE l = strlen(s);
2304 char *s1 = (char *)Perl_malloc(l+1);
2306 Copy(s, s1, (MEM_SIZE)(l+1), char);
2312 Perl_putenv(char *a)
2314 /* Sometimes system's putenv conflicts with my_setenv() - this is system
2315 malloc vs Perl's free(). */
2322 while (*val && *val != '=')
2327 if (l < sizeof(buf))
2330 var = Perl_malloc(l + 1);
2331 Copy(a, var, l, char);
2333 my_setenv(var, val+1);
2341 Perl_malloced_size(void *p)
2343 union overhead *ovp = (union overhead *)
2344 ((caddr_t)p - sizeof (union overhead) * CHUNK_SHIFT);
2345 int bucket = OV_INDEX(ovp);
2347 /* The caller wants to have a complete control over the chunk,
2348 disable the memory checking inside the chunk. */
2349 if (bucket <= MAX_SHORT_BUCKET) {
2350 MEM_SIZE size = BUCKET_SIZE_REAL(bucket);
2351 ovp->ov_size = size + M_OVERHEAD - 1;
2352 *((u_int *)((caddr_t)ovp + size + M_OVERHEAD - RMAGIC_SZ)) = RMAGIC;
2355 return BUCKET_SIZE_REAL(bucket);
2358 # ifdef BUCKETS_ROOT2
2359 # define MIN_EVEN_REPORT 6
2361 # define MIN_EVEN_REPORT MIN_BUCKET
2365 Perl_get_mstats(pTHX_ perl_mstats_t *buf, int buflen, int level)
2367 #ifdef DEBUGGING_MSTATS
2369 register union overhead *p;
2370 struct chunk_chain_s* nextchain;
2372 buf->topbucket = buf->topbucket_ev = buf->topbucket_odd
2373 = buf->totfree = buf->total = buf->total_chain = 0;
2375 buf->minbucket = MIN_BUCKET;
2377 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
2378 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
2382 buf->ntotal[i] = nmalloc[i];
2384 buf->totfree += j * BUCKET_SIZE_REAL(i);
2385 buf->total += nmalloc[i] * BUCKET_SIZE_REAL(i);
2387 i % 2 ? (buf->topbucket_odd = i) : (buf->topbucket_ev = i);
2391 nextchain = chunk_chain;
2393 buf->total_chain += nextchain->size;
2394 nextchain = nextchain->next;
2396 buf->total_sbrk = goodsbrk + sbrk_slack;
2398 buf->sbrk_good = sbrk_goodness;
2399 buf->sbrk_slack = sbrk_slack;
2400 buf->start_slack = start_slack;
2401 buf->sbrked_remains = sbrked_remains;
2403 buf->nbuckets = NBUCKETS;
2405 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
2408 buf->bucket_mem_size[i] = BUCKET_SIZE_NO_SURPLUS(i);
2409 buf->bucket_available_size[i] = BUCKET_SIZE_REAL(i);
2412 #endif /* defined DEBUGGING_MSTATS */
2413 return 0; /* XXX unused */
2416 * mstats - print out statistics about malloc
2418 * Prints two lines of numbers, one showing the length of the free list
2419 * for each size category, the second showing the number of mallocs -
2420 * frees for each size category.
2423 Perl_dump_mstats(pTHX_ char *s)
2425 #ifdef DEBUGGING_MSTATS
2427 perl_mstats_t buffer;
2433 get_mstats(&buffer, NBUCKETS, 0);
2436 PerlIO_printf(Perl_error_log,
2437 "Memory allocation statistics %s (buckets %"IVdf"(%"IVdf")..%"IVdf"(%"IVdf")\n",
2439 (IV)BUCKET_SIZE_REAL(MIN_BUCKET),
2440 (IV)BUCKET_SIZE_NO_SURPLUS(MIN_BUCKET),
2441 (IV)BUCKET_SIZE_REAL(buffer.topbucket),
2442 (IV)BUCKET_SIZE_NO_SURPLUS(buffer.topbucket));
2443 PerlIO_printf(Perl_error_log, "%8"IVdf" free:", buffer.totfree);
2444 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
2445 PerlIO_printf(Perl_error_log,
2446 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2448 : ((i < 12*BUCKETS_PER_POW2) ? " %3"UVuf : " %"UVuf)),
2451 #ifdef BUCKETS_ROOT2
2452 PerlIO_printf(Perl_error_log, "\n\t ");
2453 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
2454 PerlIO_printf(Perl_error_log,
2455 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2457 : ((i < 12*BUCKETS_PER_POW2) ? " %3"UVuf : " %"UVuf)),
2461 PerlIO_printf(Perl_error_log, "\n%8"IVdf" used:", buffer.total - buffer.totfree);
2462 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
2463 PerlIO_printf(Perl_error_log,
2464 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2466 : ((i < 12*BUCKETS_PER_POW2) ? " %3"IVdf : " %"IVdf)),
2467 buffer.ntotal[i] - buffer.nfree[i]);
2469 #ifdef BUCKETS_ROOT2
2470 PerlIO_printf(Perl_error_log, "\n\t ");
2471 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
2472 PerlIO_printf(Perl_error_log,
2473 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2475 : ((i < 12*BUCKETS_PER_POW2) ? " %3"IVdf : " %"IVdf)),
2476 buffer.ntotal[i] - buffer.nfree[i]);
2479 PerlIO_printf(Perl_error_log, "\nTotal sbrk(): %"IVdf"/%"IVdf":%"IVdf". Odd ends: pad+heads+chain+tail: %"IVdf"+%"IVdf"+%"IVdf"+%"IVdf".\n",
2480 buffer.total_sbrk, buffer.sbrks, buffer.sbrk_good,
2481 buffer.sbrk_slack, buffer.start_slack,
2482 buffer.total_chain, buffer.sbrked_remains);
2483 #endif /* DEBUGGING_MSTATS */
2487 #ifdef USE_PERL_SBRK
2489 # if defined(__MACHTEN_PPC__) || defined(NeXT) || defined(__NeXT__) || defined(PURIFY)
2490 # define PERL_SBRK_VIA_MALLOC
2493 # ifdef PERL_SBRK_VIA_MALLOC
2495 /* it may seem schizophrenic to use perl's malloc and let it call system */
2496 /* malloc, the reason for that is only the 3.2 version of the OS that had */
2497 /* frequent core dumps within nxzonefreenolock. This sbrk routine put an */
2498 /* end to the cores */
2500 # ifndef SYSTEM_ALLOC
2501 # define SYSTEM_ALLOC(a) malloc(a)
2503 # ifndef SYSTEM_ALLOC_ALIGNMENT
2504 # define SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES
2507 # endif /* PERL_SBRK_VIA_MALLOC */
2509 static IV Perl_sbrk_oldchunk;
2510 static long Perl_sbrk_oldsize;
2512 # define PERLSBRK_32_K (1<<15)
2513 # define PERLSBRK_64_K (1<<16)
2521 if (!size) return 0;
2523 reqsize = size; /* just for the DEBUG_m statement */
2526 size = (size + 0x7ff) & ~0x7ff;
2528 if (size <= Perl_sbrk_oldsize) {
2529 got = Perl_sbrk_oldchunk;
2530 Perl_sbrk_oldchunk += size;
2531 Perl_sbrk_oldsize -= size;
2533 if (size >= PERLSBRK_32_K) {
2536 size = PERLSBRK_64_K;
2539 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2540 size += NEEDED_ALIGNMENT - SYSTEM_ALLOC_ALIGNMENT;
2542 got = (IV)SYSTEM_ALLOC(size);
2543 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2544 got = (got + NEEDED_ALIGNMENT - 1) & ~(NEEDED_ALIGNMENT - 1);
2547 /* Chunk is small, register the rest for future allocs. */
2548 Perl_sbrk_oldchunk = got + reqsize;
2549 Perl_sbrk_oldsize = size - reqsize;
2553 DEBUG_m(PerlIO_printf(Perl_debug_log, "sbrk malloc size %ld (reqsize %ld), left size %ld, give addr 0x%"UVxf"\n",
2554 size, reqsize, Perl_sbrk_oldsize, PTR2UV(got)));
2559 #endif /* ! defined USE_PERL_SBRK */