6 * 'The Chamber of Records,' said Gimli. 'I guess that is where we now stand.'
8 * [p.321 of _The Lord of the Rings_, II/v: "The Bridge of Khazad-Dûm"]
11 /* This file contains Perl's own implementation of the malloc library.
12 * It is used if Configure decides that, on your platform, Perl's
13 * version is better than the OS's, or if you give Configure the
14 * -Dusemymalloc command-line option.
18 Here are some notes on configuring Perl's malloc. (For non-perl
21 There are two macros which serve as bulk disablers of advanced
22 features of this malloc: NO_FANCY_MALLOC, PLAIN_MALLOC (undef by
23 default). Look in the list of default values below to understand
24 their exact effect. Defining NO_FANCY_MALLOC returns malloc.c to the
25 state of the malloc in Perl 5.004. Additionally defining PLAIN_MALLOC
26 returns it to the state as of Perl 5.000.
28 Note that some of the settings below may be ignored in the code based
29 on values of other macros. The PERL_CORE symbol is only defined when
30 perl itself is being compiled (so malloc can make some assumptions
31 about perl's facilities being available to it).
33 Each config option has a short description, followed by its name,
34 default value, and a comment about the default (if applicable). Some
35 options take a precise value, while the others are just boolean.
36 The boolean ones are listed first.
38 # Read configuration settings from malloc_cfg.h
39 HAVE_MALLOC_CFG_H undef
41 # Enable code for an emergency memory pool in $^M. See perlvar.pod
42 # for a description of $^M.
43 PERL_EMERGENCY_SBRK (!PLAIN_MALLOC && (PERL_CORE || !NO_MALLOC_DYNAMIC_CFG))
45 # Enable code for printing memory statistics.
46 DEBUGGING_MSTATS (!PLAIN_MALLOC && PERL_CORE)
48 # Move allocation info for small buckets into separate areas.
49 # Memory optimization (especially for small allocations, of the
50 # less than 64 bytes). Since perl usually makes a large number
51 # of small allocations, this is usually a win.
52 PACK_MALLOC (!PLAIN_MALLOC && !RCHECK)
54 # Add one page to big powers of two when calculating bucket size.
55 # This is targeted at big allocations, as are common in image
57 TWO_POT_OPTIMIZE !PLAIN_MALLOC
59 # Use intermediate bucket sizes between powers-of-two. This is
60 # generally a memory optimization, and a (small) speed pessimization.
61 BUCKETS_ROOT2 !NO_FANCY_MALLOC
63 # Do not check small deallocations for bad free(). Memory
64 # and speed optimization, error reporting pessimization.
65 IGNORE_SMALL_BAD_FREE (!NO_FANCY_MALLOC && !RCHECK)
67 # Use table lookup to decide in which bucket a given allocation will go.
68 SMALL_BUCKET_VIA_TABLE !NO_FANCY_MALLOC
70 # Use a perl-defined sbrk() instead of the (presumably broken or
71 # missing) system-supplied sbrk().
74 # Use system malloc() (or calloc() etc.) to emulate sbrk(). Normally
75 # only used with broken sbrk()s.
76 PERL_SBRK_VIA_MALLOC undef
78 # Which allocator to use if PERL_SBRK_VIA_MALLOC
79 SYSTEM_ALLOC(a) malloc(a)
81 # Minimal alignment (in bytes, should be a power of 2) of SYSTEM_ALLOC
82 SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES
84 # Disable memory overwrite checking with DEBUGGING. Memory and speed
85 # optimization, error reporting pessimization.
88 # Enable memory overwrite checking with DEBUGGING. Memory and speed
89 # pessimization, error reporting optimization
90 RCHECK (DEBUGGING && !NO_RCHECK)
92 # Do not overwrite uninit areas with DEBUGGING. Speed
93 # optimization, error reporting pessimization
96 # Overwrite uninit areas with DEBUGGING. Speed
97 # pessimization, error reporting optimization
98 MALLOC_FILL (DEBUGGING && !NO_RCHECK && !NO_MFILL)
100 # Do not check overwritten uninit areas with DEBUGGING. Speed
101 # optimization, error reporting pessimization
104 # Check overwritten uninit areas with DEBUGGING. Speed
105 # pessimization, error reporting optimization
106 MALLOC_FILL_CHECK (DEBUGGING && !NO_RCHECK && !NO_FILL_CHECK)
108 # Failed allocations bigger than this size croak (if
109 # PERL_EMERGENCY_SBRK is enabled) without touching $^M. See
110 # perlvar.pod for a description of $^M.
111 BIG_SIZE (1<<16) # 64K
113 # Starting from this power of two, add an extra page to the
114 # size of the bucket. This enables optimized allocations of sizes
115 # close to powers of 2. Note that the value is indexed at 0.
116 FIRST_BIG_POW2 15 # 32K, 16K is used too often
118 # Estimate of minimal memory footprint. malloc uses this value to
119 # request the most reasonable largest blocks of memory from the system.
122 # Round up sbrk()s to multiples of this.
125 # Round up sbrk()s to multiples of this percent of footprint.
128 # Round up sbrk()s to multiples of this multiple of 1/1000 of footprint.
129 MIN_SBRK_FRAC1000 (10 * MIN_SBRK_FRAC)
131 # Add this much memory to big powers of two to get the bucket size.
134 # This many sbrk() discontinuities should be tolerated even
135 # from the start without deciding that sbrk() is usually
137 SBRK_ALLOW_FAILURES 3
139 # This many continuous sbrk()s compensate for one discontinuous one.
140 SBRK_FAILURE_PRICE 50
142 # Some configurations may ask for 12-byte-or-so allocations which
143 # require 8-byte alignment (?!). In such situation one needs to
144 # define this to disable 12-byte bucket (will increase memory footprint)
145 STRICT_ALIGNMENT undef
147 # Do not allow configuration of runtime options at runtime
148 NO_MALLOC_DYNAMIC_CFG undef
150 # Do not allow configuration of runtime options via $ENV{PERL_MALLOC_OPT}
151 NO_PERL_MALLOC_ENV undef
153 [The variable consists of ;-separated parts of the form CODE=VALUE
154 with 1-character codes F, M, f, A, P, G, d, a, c for runtime
155 configuration of FIRST_SBRK, MIN_SBRK, MIN_SBRK_FRAC1000,
156 SBRK_ALLOW_FAILURES, SBRK_FAILURE_PRICE, sbrk_goodness,
157 filldead, fillalive, fillcheck. The last 3 are for DEBUGGING
158 build, and allow switching the tests for free()ed memory read,
159 uninit memory reads, and free()ed memory write.]
161 This implementation assumes that calling PerlIO_printf() does not
162 result in any memory allocation calls (used during a panic).
167 If used outside of Perl environment, it may be useful to redefine
168 the following macros (listed below with defaults):
170 # Type of address returned by allocation functions
173 # Type of size argument for allocation functions
174 MEM_SIZE unsigned long
179 # Maximal value in LONG
182 # Unsigned integer type big enough to keep a pointer
185 # Signed integer of the same sizeof() as UV
188 # Type of pointer with 1-byte granularity
191 # Type returned by free()
194 # Conversion of pointer to integer
195 PTR2UV(ptr) ((UV)(ptr))
197 # Conversion of integer to pointer
198 INT2PTR(type, i) ((type)(i))
200 # printf()-%-Conversion of UV to pointer
203 # printf()-%-Conversion of UV to hex pointer
209 # Very fatal condition reporting function (cannot call any )
210 fatalcroak(arg) write(2,arg,strlen(arg)) + exit(2)
212 # Fatal error reporting function
213 croak(format, arg) warn(idem) + exit(1)
215 # Fatal error reporting function
216 croak2(format, arg1, arg2) warn2(idem) + exit(1)
218 # Error reporting function
219 warn(format, arg) fprintf(stderr, idem)
221 # Error reporting function
222 warn2(format, arg1, arg2) fprintf(stderr, idem)
224 # Locking/unlocking for MT operation
225 MALLOC_LOCK MUTEX_LOCK(&PL_malloc_mutex)
226 MALLOC_UNLOCK MUTEX_UNLOCK(&PL_malloc_mutex)
228 # Locking/unlocking mutex for MT operation
233 #ifdef HAVE_MALLOC_CFG_H
234 # include "malloc_cfg.h"
237 #ifndef NO_FANCY_MALLOC
238 # ifndef SMALL_BUCKET_VIA_TABLE
239 # define SMALL_BUCKET_VIA_TABLE
241 # ifndef BUCKETS_ROOT2
242 # define BUCKETS_ROOT2
244 # ifndef IGNORE_SMALL_BAD_FREE
245 # define IGNORE_SMALL_BAD_FREE
249 #ifndef PLAIN_MALLOC /* Bulk enable features */
253 # ifndef TWO_POT_OPTIMIZE
254 # define TWO_POT_OPTIMIZE
256 # if (defined(PERL_CORE) || !defined(NO_MALLOC_DYNAMIC_CFG)) && !defined(PERL_EMERGENCY_SBRK)
257 # define PERL_EMERGENCY_SBRK
259 # if defined(PERL_CORE) && !defined(DEBUGGING_MSTATS)
260 # define DEBUGGING_MSTATS
264 #define MIN_BUC_POW2 (sizeof(void*) > 4 ? 3 : 2) /* Allow for 4-byte arena. */
265 #define MIN_BUCKET (MIN_BUC_POW2 * BUCKETS_PER_POW2)
267 #if !(defined(I286) || defined(atarist))
268 /* take 2k unless the block is bigger than that */
269 # define LOG_OF_MIN_ARENA 11
271 /* take 16k unless the block is bigger than that
272 (80286s like large segments!), probably good on the atari too */
273 # define LOG_OF_MIN_ARENA 14
276 #if defined(DEBUGGING) && !defined(NO_RCHECK)
279 #if defined(DEBUGGING) && !defined(NO_RCHECK) && !defined(NO_MFILL) && !defined(MALLOC_FILL)
282 #if defined(DEBUGGING) && !defined(NO_RCHECK) && !defined(NO_FILL_CHECK) && !defined(MALLOC_FILL_CHECK)
283 # define MALLOC_FILL_CHECK
285 #if defined(RCHECK) && defined(IGNORE_SMALL_BAD_FREE)
286 # undef IGNORE_SMALL_BAD_FREE
289 * malloc.c (Caltech) 2/21/82
290 * Chris Kingsley, kingsley@cit-20.
292 * This is a very fast storage allocator. It allocates blocks of a small
293 * number of different sizes, and keeps free lists of each size. Blocks that
294 * don't exactly fit are passed up to the next larger size. In this
295 * implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long.
296 * If PACK_MALLOC is defined, small blocks are 2^n bytes long.
297 * This is designed for use in a program that uses vast quantities of memory,
298 * but bombs when it runs out.
300 * Modifications Copyright Ilya Zakharevich 1996-99.
302 * Still very quick, but much more thrifty. (Std config is 10% slower
303 * than it was, and takes 67% of old heap size for typical usage.)
305 * Allocations of small blocks are now table-driven to many different
306 * buckets. Sizes of really big buckets are increased to accommodate
307 * common size=power-of-2 blocks. Running-out-of-memory is made into
308 * an exception. Deeply configurable and thread-safe.
314 # define PERL_IN_MALLOC_C
316 # if defined(PERL_IMPLICIT_CONTEXT)
317 # define croak Perl_croak_nocontext
318 # define croak2 Perl_croak_nocontext
319 # define warn Perl_warn_nocontext
320 # define warn2 Perl_warn_nocontext
322 # define croak2 croak
325 # if defined(USE_5005THREADS) || defined(USE_ITHREADS)
326 # define PERL_MAYBE_ALIVE PL_thr_key
328 # define PERL_MAYBE_ALIVE 1
332 # include "../EXTERN.h"
333 # include "../perl.h"
343 # define Malloc_t void *
349 # define MEM_SIZE unsigned long
352 # define LONG_MAX 0x7FFFFFFF
355 # define UV unsigned long
361 # define caddr_t char *
366 # define Copy(s,d,n,t) (void)memcpy((char*)(d),(char*)(s), (n) * sizeof(t))
367 # define CopyD(s,d,n,t) memcpy((char*)(d),(char*)(s), (n) * sizeof(t))
368 # define PerlEnv_getenv getenv
369 # define PerlIO_printf fprintf
370 # define PerlIO_stderr() stderr
371 # define PerlIO_puts(f,s) fputs(s,f)
373 # define INT2PTR(t,i) ((t)(i))
376 # define PTR2UV(p) ((UV)(p))
384 # ifndef MEM_ALIGNBYTES
385 # define MEM_ALIGNBYTES 4
388 # ifndef croak /* make depend */
389 # define croak(mess, arg) (warn((mess), (arg)), exit(1))
391 # ifndef croak2 /* make depend */
392 # define croak2(mess, arg1, arg2) (warn2((mess), (arg1), (arg2)), exit(1))
395 # define warn(mess, arg) fprintf(stderr, (mess), (arg))
398 # define warn2(mess, arg1, arg2) fprintf(stderr, (mess), (arg1), (arg2))
410 # ifdef HASATTRIBUTE_UNUSED
411 # define dTHX extern int Perl___notused PERL_UNUSED_DECL
413 # define dTHX extern int Perl___notused
416 # ifndef PERL_GET_INTERP
417 # define PERL_GET_INTERP PL_curinterp
419 # define PERL_MAYBE_ALIVE 1
421 # define Perl_malloc malloc
424 # define Perl_mfree free
426 # ifndef Perl_realloc
427 # define Perl_realloc realloc
430 # define Perl_calloc calloc
433 # define Perl_strdup strdup
435 #endif /* defined PERL_CORE */
438 # define MUTEX_LOCK(l)
442 # define MUTEX_UNLOCK(l)
446 # define MALLOC_LOCK MUTEX_LOCK(&PL_malloc_mutex)
449 #ifndef MALLOC_UNLOCK
450 # define MALLOC_UNLOCK MUTEX_UNLOCK(&PL_malloc_mutex)
453 # ifndef fatalcroak /* make depend */
454 # define fatalcroak(mess) (write(2, (mess), strlen(mess)), exit(2))
459 # define DEBUG_m(a) \
461 if (PERL_MAYBE_ALIVE && PERL_GET_THX) { \
463 if (DEBUG_m_TEST) { \
464 PL_debug &= ~DEBUG_m_FLAG; \
466 PL_debug |= DEBUG_m_FLAG; \
472 #ifdef PERL_IMPLICIT_CONTEXT
473 # define PERL_IS_ALIVE aTHX
475 # define PERL_IS_ALIVE TRUE
482 * The memory is broken into "blocks" which occupy multiples of 2K (and
483 * generally speaking, have size "close" to a power of 2). The addresses
484 * of such *unused* blocks are kept in nextf[i] with big enough i. (nextf
485 * is an array of linked lists.) (Addresses of used blocks are not known.)
487 * Moreover, since the algorithm may try to "bite" smaller blocks out
488 * of unused bigger ones, there are also regions of "irregular" size,
489 * managed separately, by a linked list chunk_chain.
491 * The third type of storage is the sbrk()ed-but-not-yet-used space, its
492 * end and size are kept in last_sbrk_top and sbrked_remains.
494 * Growing blocks "in place":
495 * ~~~~~~~~~~~~~~~~~~~~~~~~~
496 * The address of the block with the greatest address is kept in last_op
497 * (if not known, last_op is 0). If it is known that the memory above
498 * last_op is not continuous, or contains a chunk from chunk_chain,
499 * last_op is set to 0.
501 * The chunk with address last_op may be grown by expanding into
502 * sbrk()ed-but-not-yet-used space, or trying to sbrk() more continuous
505 * Management of last_op:
506 * ~~~~~~~~~~~~~~~~~~~~~
508 * free() never changes the boundaries of blocks, so is not relevant.
510 * The only way realloc() may change the boundaries of blocks is if it
511 * grows a block "in place". However, in the case of success such a
512 * chunk is automatically last_op, and it remains last_op. In the case
513 * of failure getpages_adjacent() clears last_op.
515 * malloc() may change blocks by calling morecore() only.
517 * morecore() may create new blocks by:
518 * a) biting pieces from chunk_chain (cannot create one above last_op);
519 * b) biting a piece from an unused block (if block was last_op, this
520 * may create a chunk from chain above last_op, thus last_op is
521 * invalidated in such a case).
522 * c) biting of sbrk()ed-but-not-yet-used space. This creates
523 * a block which is last_op.
524 * d) Allocating new pages by calling getpages();
526 * getpages() creates a new block. It marks last_op at the bottom of
527 * the chunk of memory it returns.
529 * Active pages footprint:
530 * ~~~~~~~~~~~~~~~~~~~~~~
531 * Note that we do not need to traverse the lists in nextf[i], just take
532 * the first element of this list. However, we *need* to traverse the
533 * list in chunk_chain, but most the time it should be a very short one,
534 * so we do not step on a lot of pages we are not going to use.
538 * get_from_bigger_buckets(): forget to increment price => Quite
542 /* I don't much care whether these are defined in sys/types.h--LAW */
544 #define u_char unsigned char
545 #define u_int unsigned int
547 * I removed the definition of u_bigint which appeared to be u_bigint = UV
548 * u_bigint was only used in TWOK_MASKED and TWOK_SHIFT
549 * where I have used PTR2UV. RMB
551 #define u_short unsigned short
553 /* 286 and atarist like big chunks, which gives too much overhead. */
554 #if (defined(RCHECK) || defined(I286) || defined(atarist)) && defined(PACK_MALLOC)
559 * The description below is applicable if PACK_MALLOC is not defined.
561 * The overhead on a block is at least 4 bytes. When free, this space
562 * contains a pointer to the next free block, and the bottom two bits must
563 * be zero. When in use, the first byte is set to MAGIC, and the second
564 * byte is the size index. The remaining bytes are for alignment.
565 * If range checking is enabled and the size of the block fits
566 * in two bytes, then the top two bytes hold the size of the requested block
567 * plus the range checking words, and the header word MINUS ONE.
570 union overhead *ov_next; /* when free */
571 #if MEM_ALIGNBYTES > 4
572 double strut; /* alignment problems */
573 # if MEM_ALIGNBYTES > 8
574 char sstrut[MEM_ALIGNBYTES]; /* for the sizing */
579 * Keep the ovu_index and ovu_magic in this order, having a char
580 * field first gives alignment indigestion in some systems, such as
583 u_char ovu_index; /* bucket # */
584 u_char ovu_magic; /* magic number */
586 /* Subtract one to fit into u_short for an extra bucket */
587 u_short ovu_size; /* block size (requested + overhead - 1) */
588 u_int ovu_rmagic; /* range magic number */
591 #define ov_magic ovu.ovu_magic
592 #define ov_index ovu.ovu_index
593 #define ov_size ovu.ovu_size
594 #define ov_rmagic ovu.ovu_rmagic
597 #define MAGIC 0xff /* magic # on accounting info */
598 #define RMAGIC 0x55555555 /* magic # on range info */
599 #define RMAGIC_C 0x55 /* magic # on range info */
602 # define RMAGIC_SZ sizeof (u_int) /* Overhead at end of bucket */
603 # ifdef TWO_POT_OPTIMIZE
604 # define MAX_SHORT_BUCKET (12 * BUCKETS_PER_POW2) /* size-1 fits in short */
606 # define MAX_SHORT_BUCKET (13 * BUCKETS_PER_POW2)
612 #if !defined(PACK_MALLOC) && defined(BUCKETS_ROOT2)
613 # undef BUCKETS_ROOT2
617 # define BUCKET_TABLE_SHIFT 2
618 # define BUCKET_POW2_SHIFT 1
619 # define BUCKETS_PER_POW2 2
621 # define BUCKET_TABLE_SHIFT MIN_BUC_POW2
622 # define BUCKET_POW2_SHIFT 0
623 # define BUCKETS_PER_POW2 1
626 #if !defined(MEM_ALIGNBYTES) || ((MEM_ALIGNBYTES > 4) && !defined(STRICT_ALIGNMENT))
627 /* Figure out the alignment of void*. */
632 # define ALIGN_SMALL ((int)((caddr_t)&(((struct aligner*)0)->p)))
634 # define ALIGN_SMALL MEM_ALIGNBYTES
637 #define IF_ALIGN_8(yes,no) ((ALIGN_SMALL>4) ? (yes) : (no))
640 # define MAX_BUCKET_BY_TABLE 13
641 static const u_short buck_size[MAX_BUCKET_BY_TABLE + 1] =
643 0, 0, 0, 0, 4, 4, 8, 12, 16, 24, 32, 48, 64, 80,
645 # define BUCKET_SIZE_NO_SURPLUS(i) ((i) % 2 ? buck_size[i] : (1 << ((i) >> BUCKET_POW2_SHIFT)))
646 # define BUCKET_SIZE_REAL(i) ((i) <= MAX_BUCKET_BY_TABLE \
648 : ((1 << ((i) >> BUCKET_POW2_SHIFT)) \
650 + POW2_OPTIMIZE_SURPLUS(i)))
652 # define BUCKET_SIZE_NO_SURPLUS(i) (1 << ((i) >> BUCKET_POW2_SHIFT))
653 # define BUCKET_SIZE(i) (BUCKET_SIZE_NO_SURPLUS(i) + POW2_OPTIMIZE_SURPLUS(i))
654 # define BUCKET_SIZE_REAL(i) (BUCKET_SIZE(i) - MEM_OVERHEAD(i))
659 /* In this case there are several possible layout of arenas depending
660 * on the size. Arenas are of sizes multiple to 2K, 2K-aligned, and
661 * have a size close to a power of 2.
663 * Arenas of the size >= 4K keep one chunk only. Arenas of size 2K
664 * may keep one chunk or multiple chunks. Here are the possible
667 * # One chunk only, chunksize 2^k + SOMETHING - ALIGN, k >= 11
669 * INDEX MAGIC1 UNUSED CHUNK1
671 * # Multichunk with sanity checking and chunksize 2^k-ALIGN, k>7
673 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 CHUNK2 CHUNK3 ...
675 * # Multichunk with sanity checking and size 2^k-ALIGN, k=7
677 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 UNUSED CHUNK2 CHUNK3 ...
679 * # Multichunk with sanity checking and size up to 80
681 * INDEX UNUSED MAGIC1 UNUSED MAGIC2 UNUSED ... CHUNK1 CHUNK2 CHUNK3 ...
683 * # No sanity check (usually up to 48=byte-long buckets)
684 * INDEX UNUSED CHUNK1 CHUNK2 ...
686 * Above INDEX and MAGIC are one-byte-long. Sizes of UNUSED are
687 * appropriate to keep algorithms simple and memory aligned. INDEX
688 * encodes the size of the chunk, while MAGICn encodes state (used,
689 * free or non-managed-by-us-so-it-indicates-a-bug) of CHUNKn. MAGIC
690 * is used for sanity checking purposes only. SOMETHING is 0 or 4K
691 * (to make size of big CHUNK accommodate allocations for powers of two
694 * [There is no need to alignment between chunks, since C rules ensure
695 * that structs which need 2^k alignment have sizeof which is
696 * divisible by 2^k. Thus as far as the last chunk is aligned at the
697 * end of the arena, and 2K-alignment does not contradict things,
698 * everything is going to be OK for sizes of chunks 2^n and 2^n +
699 * 2^k. Say, 80-bit buckets will be 16-bit aligned, and as far as we
700 * put allocations for requests in 65..80 range, all is fine.
702 * Note, however, that standard malloc() puts more strict
703 * requirements than the above C rules. Moreover, our algorithms of
704 * realloc() may break this idyll, but we suppose that realloc() does
705 * need not change alignment.]
707 * Is very important to make calculation of the offset of MAGICm as
708 * quick as possible, since it is done on each malloc()/free(). In
709 * fact it is so quick that it has quite little effect on the speed of
710 * doing malloc()/free(). [By default] We forego such calculations
711 * for small chunks, but only to save extra 3% of memory, not because
712 * of speed considerations.
714 * Here is the algorithm [which is the same for all the allocations
715 * schemes above], see OV_MAGIC(block,bucket). Let OFFSETm be the
716 * offset of the CHUNKm from the start of ARENA. Then offset of
717 * MAGICm is (OFFSET1 >> SHIFT) + ADDOFFSET. Here SHIFT and ADDOFFSET
718 * are numbers which depend on the size of the chunks only.
720 * Let as check some sanity conditions. Numbers OFFSETm>>SHIFT are
721 * different for all the chunks in the arena if 2^SHIFT is not greater
722 * than size of the chunks in the arena. MAGIC1 will not overwrite
723 * INDEX provided ADDOFFSET is >0 if OFFSET1 < 2^SHIFT. MAGIClast
724 * will not overwrite CHUNK1 if OFFSET1 > (OFFSETlast >> SHIFT) +
727 * Make SHIFT the maximal possible (there is no point in making it
728 * smaller). Since OFFSETlast is 2K - CHUNKSIZE, above restrictions
729 * give restrictions on OFFSET1 and on ADDOFFSET.
731 * In particular, for chunks of size 2^k with k>=6 we can put
732 * ADDOFFSET to be from 0 to 2^k - 2^(11-k), and have
733 * OFFSET1==chunksize. For chunks of size 80 OFFSET1 of 2K%80=48 is
734 * large enough to have ADDOFFSET between 1 and 16 (similarly for 96,
735 * when ADDOFFSET should be 1). In particular, keeping MAGICs for
736 * these sizes gives no additional size penalty.
738 * However, for chunks of size 2^k with k<=5 this gives OFFSET1 >=
739 * ADDOFSET + 2^(11-k). Keeping ADDOFFSET 0 allows for 2^(11-k)-2^(11-2k)
740 * chunks per arena. This is smaller than 2^(11-k) - 1 which are
741 * needed if no MAGIC is kept. [In fact, having a negative ADDOFFSET
742 * would allow for slightly more buckets per arena for k=2,3.]
744 * Similarly, for chunks of size 3/2*2^k with k<=5 MAGICs would span
745 * the area up to 2^(11-k)+ADDOFFSET. For k=4 this give optimal
746 * ADDOFFSET as -7..0. For k=3 ADDOFFSET can go up to 4 (with tiny
747 * savings for negative ADDOFFSET). For k=5 ADDOFFSET can go -1..16
748 * (with no savings for negative values).
750 * In particular, keeping ADDOFFSET 0 for sizes of chunks up to 2^6
751 * leads to tiny pessimizations in case of sizes 4, 8, 12, 24, and
752 * leads to no contradictions except for size=80 (or 96.)
754 * However, it also makes sense to keep no magic for sizes 48 or less.
755 * This is what we do. In this case one needs ADDOFFSET>=1 also for
756 * chunksizes 12, 24, and 48, unless one gets one less chunk per
759 * The algo of OV_MAGIC(block,bucket) keeps ADDOFFSET 0 until
760 * chunksize of 64, then makes it 1.
762 * This allows for an additional optimization: the above scheme leads
763 * to giant overheads for sizes 128 or more (one whole chunk needs to
764 * be sacrifised to keep INDEX). Instead we use chunks not of size
765 * 2^k, but of size 2^k-ALIGN. If we pack these chunks at the end of
766 * the arena, then the beginnings are still in different 2^k-long
767 * sections of the arena if k>=7 for ALIGN==4, and k>=8 if ALIGN=8.
768 * Thus for k>7 the above algo of calculating the offset of the magic
769 * will still give different answers for different chunks. And to
770 * avoid the overrun of MAGIC1 into INDEX, one needs ADDOFFSET of >=1.
771 * In the case k=7 we just move the first chunk an extra ALIGN
772 * backward inside the ARENA (this is done once per arena lifetime,
773 * thus is not a big overhead). */
774 # define MAX_PACKED_POW2 6
775 # define MAX_PACKED (MAX_PACKED_POW2 * BUCKETS_PER_POW2 + BUCKET_POW2_SHIFT)
776 # define MAX_POW2_ALGO ((1<<(MAX_PACKED_POW2 + 1)) - M_OVERHEAD)
777 # define TWOK_MASK ((1<<LOG_OF_MIN_ARENA) - 1)
778 # define TWOK_MASKED(x) (PTR2UV(x) & ~TWOK_MASK)
779 # define TWOK_SHIFT(x) (PTR2UV(x) & TWOK_MASK)
780 # define OV_INDEXp(block) (INT2PTR(u_char*,TWOK_MASKED(block)))
781 # define OV_INDEX(block) (*OV_INDEXp(block))
782 # define OV_MAGIC(block,bucket) (*(OV_INDEXp(block) + \
783 (TWOK_SHIFT(block)>> \
784 (bucket>>BUCKET_POW2_SHIFT)) + \
785 (bucket >= MIN_NEEDS_SHIFT ? 1 : 0)))
786 /* A bucket can have a shift smaller than it size, we need to
787 shift its magic number so it will not overwrite index: */
788 # ifdef BUCKETS_ROOT2
789 # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2 - 1) /* Shift 80 greater than chunk 64. */
791 # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2) /* Shift 128 greater than chunk 32. */
793 # define CHUNK_SHIFT 0
795 /* Number of active buckets of given ordinal. */
796 #ifdef IGNORE_SMALL_BAD_FREE
797 #define FIRST_BUCKET_WITH_CHECK (6 * BUCKETS_PER_POW2) /* 64 */
798 # define N_BLKS(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \
799 ? ((1<<LOG_OF_MIN_ARENA) - 1)/BUCKET_SIZE_NO_SURPLUS(bucket) \
802 # define N_BLKS(bucket) n_blks[bucket]
805 static const u_short n_blks[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
807 # if BUCKETS_PER_POW2==1
809 (MIN_BUC_POW2==2 ? 384 : 0),
810 224, 120, 62, 31, 16, 8, 4, 2
813 (MIN_BUC_POW2==2 ? 384 : 0), (MIN_BUC_POW2==2 ? 384 : 0), /* 4, 4 */
814 224, 149, 120, 80, 62, 41, 31, 25, 16, 16, 8, 8, 4, 4, 2, 2
818 /* Shift of the first bucket with the given ordinal inside 2K chunk. */
819 #ifdef IGNORE_SMALL_BAD_FREE
820 # define BLK_SHIFT(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \
821 ? ((1<<LOG_OF_MIN_ARENA) \
822 - BUCKET_SIZE_NO_SURPLUS(bucket) * N_BLKS(bucket)) \
825 # define BLK_SHIFT(bucket) blk_shift[bucket]
828 static const u_short blk_shift[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
830 # if BUCKETS_PER_POW2==1
832 (MIN_BUC_POW2==2 ? 512 : 0),
833 256, 128, 64, 64, /* 8 to 64 */
834 16*sizeof(union overhead),
835 8*sizeof(union overhead),
836 4*sizeof(union overhead),
837 2*sizeof(union overhead),
840 (MIN_BUC_POW2==2 ? 512 : 0), (MIN_BUC_POW2==2 ? 512 : 0),
841 256, 260, 128, 128, 64, 80, 64, 48, /* 8 to 96 */
842 16*sizeof(union overhead), 16*sizeof(union overhead),
843 8*sizeof(union overhead), 8*sizeof(union overhead),
844 4*sizeof(union overhead), 4*sizeof(union overhead),
845 2*sizeof(union overhead), 2*sizeof(union overhead),
849 # define NEEDED_ALIGNMENT 0x800 /* 2k boundaries */
850 # define WANTED_ALIGNMENT 0x800 /* 2k boundaries */
852 #else /* !PACK_MALLOC */
854 # define OV_MAGIC(block,bucket) (block)->ov_magic
855 # define OV_INDEX(block) (block)->ov_index
856 # define CHUNK_SHIFT 1
857 # define MAX_PACKED -1
858 # define NEEDED_ALIGNMENT MEM_ALIGNBYTES
859 # define WANTED_ALIGNMENT 0x400 /* 1k boundaries */
861 #endif /* !PACK_MALLOC */
863 #define M_OVERHEAD (sizeof(union overhead) + RMAGIC_SZ) /* overhead at start+end */
866 # define MEM_OVERHEAD(bucket) \
867 (bucket <= MAX_PACKED ? 0 : M_OVERHEAD)
868 # ifdef SMALL_BUCKET_VIA_TABLE
869 # define START_SHIFTS_BUCKET ((MAX_PACKED_POW2 + 1) * BUCKETS_PER_POW2)
870 # define START_SHIFT MAX_PACKED_POW2
871 # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */
872 # define SIZE_TABLE_MAX 80
874 # define SIZE_TABLE_MAX 64
876 static const char bucket_of[] =
878 # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */
879 /* 0 to 15 in 4-byte increments. */
880 (sizeof(void*) > 4 ? 6 : 5), /* 4/8, 5-th bucket for better reports */
882 IF_ALIGN_8(8,7), 8, /* 16/12, 16 */
883 9, 9, 10, 10, /* 24, 32 */
884 11, 11, 11, 11, /* 48 */
885 12, 12, 12, 12, /* 64 */
886 13, 13, 13, 13, /* 80 */
887 13, 13, 13, 13 /* 80 */
888 # else /* !BUCKETS_ROOT2 */
889 /* 0 to 15 in 4-byte increments. */
890 (sizeof(void*) > 4 ? 3 : 2),
896 # endif /* !BUCKETS_ROOT2 */
898 # else /* !SMALL_BUCKET_VIA_TABLE */
899 # define START_SHIFTS_BUCKET MIN_BUCKET
900 # define START_SHIFT (MIN_BUC_POW2 - 1)
901 # endif /* !SMALL_BUCKET_VIA_TABLE */
902 #else /* !PACK_MALLOC */
903 # define MEM_OVERHEAD(bucket) M_OVERHEAD
904 # ifdef SMALL_BUCKET_VIA_TABLE
905 # undef SMALL_BUCKET_VIA_TABLE
907 # define START_SHIFTS_BUCKET MIN_BUCKET
908 # define START_SHIFT (MIN_BUC_POW2 - 1)
909 #endif /* !PACK_MALLOC */
912 * Big allocations are often of the size 2^n bytes. To make them a
913 * little bit better, make blocks of size 2^n+pagesize for big n.
916 #ifdef TWO_POT_OPTIMIZE
918 # ifndef PERL_PAGESIZE
919 # define PERL_PAGESIZE 4096
921 # ifndef FIRST_BIG_POW2
922 # define FIRST_BIG_POW2 15 /* 32K, 16K is used too often. */
924 # define FIRST_BIG_BLOCK (1<<FIRST_BIG_POW2)
925 /* If this value or more, check against bigger blocks. */
926 # define FIRST_BIG_BOUND (FIRST_BIG_BLOCK - M_OVERHEAD)
927 /* If less than this value, goes into 2^n-overhead-block. */
928 # define LAST_SMALL_BOUND ((FIRST_BIG_BLOCK>>1) - M_OVERHEAD)
930 # define POW2_OPTIMIZE_ADJUST(nbytes) \
931 ((nbytes >= FIRST_BIG_BOUND) ? nbytes -= PERL_PAGESIZE : 0)
932 # define POW2_OPTIMIZE_SURPLUS(bucket) \
933 ((bucket >= FIRST_BIG_POW2 * BUCKETS_PER_POW2) ? PERL_PAGESIZE : 0)
935 #else /* !TWO_POT_OPTIMIZE */
936 # define POW2_OPTIMIZE_ADJUST(nbytes)
937 # define POW2_OPTIMIZE_SURPLUS(bucket) 0
938 #endif /* !TWO_POT_OPTIMIZE */
940 #if defined(HAS_64K_LIMIT) && defined(PERL_CORE)
941 # define BARK_64K_LIMIT(what,nbytes,size) \
942 if (nbytes > 0xffff) { \
943 PerlIO_printf(PerlIO_stderr(), \
944 "%s too large: %lx\n", what, size); \
947 #else /* !HAS_64K_LIMIT || !PERL_CORE */
948 # define BARK_64K_LIMIT(what,nbytes,size)
949 #endif /* !HAS_64K_LIMIT || !PERL_CORE */
952 # define MIN_SBRK 2048
956 # define FIRST_SBRK (48*1024)
959 /* Minimal sbrk in percents of what is already alloced. */
960 #ifndef MIN_SBRK_FRAC
961 # define MIN_SBRK_FRAC 3
964 #ifndef SBRK_ALLOW_FAILURES
965 # define SBRK_ALLOW_FAILURES 3
968 #ifndef SBRK_FAILURE_PRICE
969 # define SBRK_FAILURE_PRICE 50
972 static void morecore (register int bucket);
973 # if defined(DEBUGGING)
974 static void botch (const char *diag, const char *s, const char *file, int line);
976 static void add_to_chain (void *p, MEM_SIZE size, MEM_SIZE chip);
977 static void* get_from_chain (MEM_SIZE size);
978 static void* get_from_bigger_buckets(int bucket, MEM_SIZE size);
979 static union overhead *getpages (MEM_SIZE needed, int *nblksp, int bucket);
980 static int getpages_adjacent(MEM_SIZE require);
984 #ifdef I_MACH_CTHREADS
986 # define MUTEX_LOCK(m) STMT_START { if (*m) mutex_lock(*m); } STMT_END
988 # define MUTEX_UNLOCK(m) STMT_START { if (*m) mutex_unlock(*m); } STMT_END
991 #endif /* defined PERL_CORE */
994 # define PTRSIZE sizeof(void*)
998 # define BITS_IN_PTR (8*PTRSIZE)
1002 * nextf[i] is the pointer to the next free block of size 2^i. The
1003 * smallest allocatable block is 8 bytes. The overhead information
1004 * precedes the data area returned to the user.
1006 #define NBUCKETS (BITS_IN_PTR*BUCKETS_PER_POW2 + 1)
1007 static union overhead *nextf[NBUCKETS];
1009 #if defined(PURIFY) && !defined(USE_PERL_SBRK)
1010 # define USE_PERL_SBRK
1013 #ifdef USE_PERL_SBRK
1014 # define sbrk(a) Perl_sbrk(a)
1015 Malloc_t Perl_sbrk (int size);
1017 # ifndef HAS_SBRK_PROTO /* <unistd.h> usually takes care of this */
1018 extern Malloc_t sbrk(int);
1022 #ifndef MIN_SBRK_FRAC1000 /* Backward compatibility */
1023 # define MIN_SBRK_FRAC1000 (MIN_SBRK_FRAC * 10)
1026 #ifndef START_EXTERN_C
1028 # define START_EXTERN_C extern "C" {
1030 # define START_EXTERN_C
1034 #ifndef END_EXTERN_C
1036 # define END_EXTERN_C };
1038 # define END_EXTERN_C
1042 #include "malloc_ctl.h"
1044 #ifndef NO_MALLOC_DYNAMIC_CFG
1045 # define PERL_MALLOC_OPT_CHARS "FMfAPGdac"
1047 # ifndef FILL_DEAD_DEFAULT
1048 # define FILL_DEAD_DEFAULT 1
1050 # ifndef FILL_ALIVE_DEFAULT
1051 # define FILL_ALIVE_DEFAULT 1
1053 # ifndef FILL_CHECK_DEFAULT
1054 # define FILL_CHECK_DEFAULT 1
1057 static IV MallocCfg[MallocCfg_last] = {
1061 SBRK_ALLOW_FAILURES,
1063 SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE, /* sbrk_goodness */
1064 FILL_DEAD_DEFAULT, /* FILL_DEAD */
1065 FILL_ALIVE_DEFAULT, /* FILL_ALIVE */
1066 FILL_CHECK_DEFAULT, /* FILL_CHECK */
1067 0, /* MallocCfg_skip_cfg_env */
1068 0, /* MallocCfg_cfg_env_read */
1069 0, /* MallocCfg_emergency_buffer_size */
1070 0, /* MallocCfg_emergency_buffer_prepared_size */
1071 0 /* MallocCfg_emergency_buffer_last_req */
1073 IV *MallocCfg_ptr = MallocCfg;
1075 static char* MallocCfgP[MallocCfg_last] = {
1076 0, /* MallocCfgP_emergency_buffer */
1077 0, /* MallocCfgP_emergency_buffer_prepared */
1079 char **MallocCfgP_ptr = MallocCfgP;
1083 # undef MIN_SBRK_FRAC1000
1084 # undef SBRK_ALLOW_FAILURES
1085 # undef SBRK_FAILURE_PRICE
1087 # define MIN_SBRK MallocCfg[MallocCfg_MIN_SBRK]
1088 # define FIRST_SBRK MallocCfg[MallocCfg_FIRST_SBRK]
1089 # define MIN_SBRK_FRAC1000 MallocCfg[MallocCfg_MIN_SBRK_FRAC1000]
1090 # define SBRK_ALLOW_FAILURES MallocCfg[MallocCfg_SBRK_ALLOW_FAILURES]
1091 # define SBRK_FAILURE_PRICE MallocCfg[MallocCfg_SBRK_FAILURE_PRICE]
1093 # define sbrk_goodness MallocCfg[MallocCfg_sbrk_goodness]
1095 # define emergency_buffer_size MallocCfg[MallocCfg_emergency_buffer_size]
1096 # define emergency_buffer_last_req MallocCfg[MallocCfg_emergency_buffer_last_req]
1098 # define FILL_DEAD MallocCfg[MallocCfg_filldead]
1099 # define FILL_ALIVE MallocCfg[MallocCfg_fillalive]
1100 # define FILL_CHECK_CFG MallocCfg[MallocCfg_fillcheck]
1101 # define FILL_CHECK (FILL_DEAD && FILL_CHECK_CFG)
1103 # define emergency_buffer MallocCfgP[MallocCfgP_emergency_buffer]
1104 # define emergency_buffer_prepared MallocCfgP[MallocCfgP_emergency_buffer_prepared]
1106 #else /* defined(NO_MALLOC_DYNAMIC_CFG) */
1108 # define FILL_DEAD 1
1109 # define FILL_ALIVE 1
1110 # define FILL_CHECK 1
1111 static int sbrk_goodness = SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE;
1113 # define NO_PERL_MALLOC_ENV
1117 #ifdef DEBUGGING_MSTATS
1119 * nmalloc[i] is the difference between the number of mallocs and frees
1120 * for a given block size.
1122 static u_int nmalloc[NBUCKETS];
1123 static u_int sbrk_slack;
1124 static u_int start_slack;
1125 #else /* !( defined DEBUGGING_MSTATS ) */
1126 # define sbrk_slack 0
1129 static u_int goodsbrk;
1131 #ifdef PERL_EMERGENCY_SBRK
1134 # define BIG_SIZE (1<<16) /* 64K */
1137 # ifdef NO_MALLOC_DYNAMIC_CFG
1138 static MEM_SIZE emergency_buffer_size;
1139 /* 0 if the last request for more memory succeeded.
1140 Otherwise the size of the failing request. */
1141 static MEM_SIZE emergency_buffer_last_req;
1142 static char *emergency_buffer;
1143 static char *emergency_buffer_prepared;
1146 # ifndef emergency_sbrk_croak
1147 # define emergency_sbrk_croak croak2
1152 perl_get_emergency_buffer(IV *size)
1155 /* First offense, give a possibility to recover by dieing. */
1156 /* No malloc involved here: */
1159 GV **gvp = (GV**)hv_fetchs(PL_defstash, "^M", FALSE);
1161 if (!gvp) gvp = (GV**)hv_fetchs(PL_defstash, "\015", FALSE);
1162 if (!gvp || !(sv = GvSV(*gvp)) || !SvPOK(sv)
1163 || (SvLEN(sv) < (1<<LOG_OF_MIN_ARENA) - M_OVERHEAD))
1164 return NULL; /* Now die die die... */
1165 /* Got it, now detach SvPV: */
1166 pv = SvPV_nolen(sv);
1167 /* Check alignment: */
1168 if ((PTR2UV(pv) - sizeof(union overhead)) & (NEEDED_ALIGNMENT - 1)) {
1169 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
1170 return NULL; /* die die die */
1177 *size = malloced_size(pv) + M_OVERHEAD;
1178 return pv - sizeof(union overhead);
1180 # define PERL_GET_EMERGENCY_BUFFER(p) perl_get_emergency_buffer(p)
1182 # define PERL_GET_EMERGENCY_BUFFER(p) NULL
1183 # endif /* defined PERL_CORE */
1185 # ifndef NO_MALLOC_DYNAMIC_CFG
1187 get_emergency_buffer(IV *size)
1189 char *pv = emergency_buffer_prepared;
1191 *size = MallocCfg[MallocCfg_emergency_buffer_prepared_size];
1192 emergency_buffer_prepared = 0;
1193 MallocCfg[MallocCfg_emergency_buffer_prepared_size] = 0;
1197 /* Returns 0 on success, -1 on bad alignment, -2 if not implemented */
1199 set_emergency_buffer(char *b, IV size)
1201 if (PTR2UV(b) & (NEEDED_ALIGNMENT - 1))
1203 if (MallocCfg[MallocCfg_emergency_buffer_prepared_size])
1204 add_to_chain((void*)emergency_buffer_prepared,
1205 MallocCfg[MallocCfg_emergency_buffer_prepared_size], 0);
1206 emergency_buffer_prepared = b;
1207 MallocCfg[MallocCfg_emergency_buffer_prepared_size] = size;
1210 # define GET_EMERGENCY_BUFFER(p) get_emergency_buffer(p)
1211 # else /* NO_MALLOC_DYNAMIC_CFG */
1212 # define GET_EMERGENCY_BUFFER(p) NULL
1214 set_emergency_buffer(char *b, IV size)
1221 emergency_sbrk(MEM_SIZE size)
1223 MEM_SIZE rsize = (((size - 1)>>LOG_OF_MIN_ARENA) + 1)<<LOG_OF_MIN_ARENA;
1225 if (size >= BIG_SIZE
1226 && (!emergency_buffer_last_req ||
1227 (size < (MEM_SIZE)emergency_buffer_last_req))) {
1228 /* Give the possibility to recover, but avoid an infinite cycle. */
1230 emergency_buffer_last_req = size;
1231 emergency_sbrk_croak("Out of memory during \"large\" request for %"UVuf" bytes, total sbrk() is %"UVuf" bytes", (UV)size, (UV)(goodsbrk + sbrk_slack));
1234 if ((MEM_SIZE)emergency_buffer_size >= rsize) {
1235 char *old = emergency_buffer;
1237 emergency_buffer_size -= rsize;
1238 emergency_buffer += rsize;
1241 /* First offense, give a possibility to recover by dieing. */
1242 /* No malloc involved here: */
1244 char *pv = GET_EMERGENCY_BUFFER(&Size);
1247 if (emergency_buffer_size) {
1248 add_to_chain(emergency_buffer, emergency_buffer_size, 0);
1249 emergency_buffer_size = 0;
1250 emergency_buffer = NULL;
1255 pv = PERL_GET_EMERGENCY_BUFFER(&Size);
1259 return (char *)-1; /* Now die die die... */
1262 /* Check alignment: */
1263 if (PTR2UV(pv) & (NEEDED_ALIGNMENT - 1)) {
1266 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
1267 return (char *)-1; /* die die die */
1270 emergency_buffer = pv;
1271 emergency_buffer_size = Size;
1275 emergency_sbrk_croak("Out of memory during request for %"UVuf" bytes, total sbrk() is %"UVuf" bytes", (UV)size, (UV)(goodsbrk + sbrk_slack));
1280 #else /* !defined(PERL_EMERGENCY_SBRK) */
1281 # define emergency_sbrk(size) -1
1282 #endif /* defined PERL_EMERGENCY_SBRK */
1285 write2(const char *mess)
1287 write(2, mess, strlen(mess));
1292 #define ASSERT(p,diag) if (!(p)) botch(diag,STRINGIFY(p),__FILE__,__LINE__);
1295 botch(const char *diag, const char *s, const char *file, int line)
1299 if (!(PERL_MAYBE_ALIVE && PERL_GET_THX))
1302 if (PerlIO_printf(PerlIO_stderr(),
1303 "assertion botched (%s?): %s %s:%d\n",
1304 diag, s, file, line) != 0) {
1305 do_write: /* Can be initializing interpreter */
1306 write2("assertion botched (");
1315 char *s = linebuf + sizeof(linebuf) - 1;
1319 *--s = '0' + (n % 10);
1329 #define ASSERT(p, diag)
1333 /* Fill should be long enough to cover long */
1335 fill_pat_4bytes(unsigned char *s, size_t nbytes, const unsigned char *fill)
1337 unsigned char *e = s + nbytes;
1339 const long lfill = *(long*)fill;
1341 if (PTR2UV(s) & (sizeof(long)-1)) { /* Align the pattern */
1342 int shift = sizeof(long) - (PTR2UV(s) & (sizeof(long)-1));
1343 unsigned const char *f = fill + sizeof(long) - shift;
1344 unsigned char *e1 = s + shift;
1350 while ((unsigned char*)(lp + 1) <= e)
1352 s = (unsigned char*)lp;
1356 /* Just malloc()ed */
1357 static const unsigned char fill_feedadad[] =
1358 {0xFE, 0xED, 0xAD, 0xAD, 0xFE, 0xED, 0xAD, 0xAD,
1359 0xFE, 0xED, 0xAD, 0xAD, 0xFE, 0xED, 0xAD, 0xAD};
1361 static const unsigned char fill_deadbeef[] =
1362 {0xDE, 0xAD, 0xBE, 0xEF, 0xDE, 0xAD, 0xBE, 0xEF,
1363 0xDE, 0xAD, 0xBE, 0xEF, 0xDE, 0xAD, 0xBE, 0xEF};
1364 # define FILL_DEADBEEF(s, n) \
1365 (void)(FILL_DEAD? (fill_pat_4bytes((s), (n), fill_deadbeef), 0) : 0)
1366 # define FILL_FEEDADAD(s, n) \
1367 (void)(FILL_ALIVE? (fill_pat_4bytes((s), (n), fill_feedadad), 0) : 0)
1369 # define FILL_DEADBEEF(s, n) ((void)0)
1370 # define FILL_FEEDADAD(s, n) ((void)0)
1371 # undef MALLOC_FILL_CHECK
1374 #ifdef MALLOC_FILL_CHECK
1376 cmp_pat_4bytes(unsigned char *s, size_t nbytes, const unsigned char *fill)
1378 unsigned char *e = s + nbytes;
1380 const long lfill = *(long*)fill;
1382 if (PTR2UV(s) & (sizeof(long)-1)) { /* Align the pattern */
1383 int shift = sizeof(long) - (PTR2UV(s) & (sizeof(long)-1));
1384 unsigned const char *f = fill + sizeof(long) - shift;
1385 unsigned char *e1 = s + shift;
1392 while ((unsigned char*)(lp + 1) <= e)
1395 s = (unsigned char*)lp;
1397 if (*s++ != *fill++)
1401 # define FILLCHECK_DEADBEEF(s, n) \
1402 ASSERT(!FILL_CHECK || !cmp_pat_4bytes(s, n, fill_deadbeef), \
1403 "free()ed/realloc()ed-away memory was overwritten")
1405 # define FILLCHECK_DEADBEEF(s, n) ((void)0)
1409 S_ajust_size_and_find_bucket(size_t *nbytes_p)
1413 size_t nbytes = *nbytes_p;
1416 * Convert amount of memory requested into
1417 * closest block size stored in hash buckets
1418 * which satisfies request. Account for
1419 * space used per block for accounting.
1422 # ifdef SMALL_BUCKET_VIA_TABLE
1424 bucket = MIN_BUCKET;
1425 else if (nbytes <= SIZE_TABLE_MAX) {
1426 bucket = bucket_of[(nbytes - 1) >> BUCKET_TABLE_SHIFT];
1431 if (nbytes <= MAX_POW2_ALGO) goto do_shifts;
1436 POW2_OPTIMIZE_ADJUST(nbytes);
1437 nbytes += M_OVERHEAD;
1438 nbytes = (nbytes + 3) &~ 3;
1439 #if defined(PACK_MALLOC) && !defined(SMALL_BUCKET_VIA_TABLE)
1442 shiftr = (nbytes - 1) >> START_SHIFT;
1443 bucket = START_SHIFTS_BUCKET;
1444 /* apart from this loop, this is O(1) */
1445 while (shiftr >>= 1)
1446 bucket += BUCKETS_PER_POW2;
1453 Perl_malloc(size_t nbytes)
1456 register union overhead *p;
1457 register int bucket;
1459 #if defined(DEBUGGING) || defined(RCHECK)
1460 MEM_SIZE size = nbytes;
1463 BARK_64K_LIMIT("Allocation",nbytes,nbytes);
1465 if ((long)nbytes < 0)
1466 croak("%s", "panic: malloc");
1469 bucket = S_ajust_size_and_find_bucket(&nbytes);
1472 * If nothing in hash bucket right now,
1473 * request more memory from the system.
1475 if (nextf[bucket] == NULL)
1477 if ((p = nextf[bucket]) == NULL) {
1483 #if defined(PLAIN_MALLOC) && defined(NO_FANCY_MALLOC)
1484 PerlIO_puts(PerlIO_stderr(),"Out of memory!\n");
1487 char *eb = buff + sizeof(buff) - 1;
1491 PerlIO_puts(PerlIO_stderr(),"Out of memory during request for ");
1492 #if defined(DEBUGGING) || defined(RCHECK)
1497 *--s = '0' + (n % 10);
1499 PerlIO_puts(PerlIO_stderr(),s);
1500 PerlIO_puts(PerlIO_stderr()," bytes, total sbrk() is ");
1502 n = goodsbrk + sbrk_slack;
1504 *--s = '0' + (n % 10);
1506 PerlIO_puts(PerlIO_stderr(),s);
1507 PerlIO_puts(PerlIO_stderr()," bytes!\n");
1508 #endif /* defined(PLAIN_MALLOC) && defined(NO_FANCY_MALLOC) */
1516 /* remove from linked list */
1518 if ( (PTR2UV(p) & (MEM_ALIGNBYTES - 1))
1519 /* Can't get this low */
1520 || (p && PTR2UV(p) < (1<<LOG_OF_MIN_ARENA)) ) {
1522 PerlIO_printf(PerlIO_stderr(),
1523 "Unaligned pointer in the free chain 0x%"UVxf"\n",
1526 if ( (PTR2UV(p->ov_next) & (MEM_ALIGNBYTES - 1))
1527 || (p->ov_next && PTR2UV(p->ov_next) < (1<<LOG_OF_MIN_ARENA)) ) {
1529 PerlIO_printf(PerlIO_stderr(),
1530 "Unaligned \"next\" pointer in the free "
1531 "chain 0x%"UVxf" at 0x%"UVxf"\n",
1532 PTR2UV(p->ov_next), PTR2UV(p));
1535 nextf[bucket] = p->ov_next;
1539 DEBUG_m(PerlIO_printf(Perl_debug_log,
1540 "0x%"UVxf": (%05lu) malloc %ld bytes\n",
1541 PTR2UV((Malloc_t)(p + CHUNK_SHIFT)), (unsigned long)(PL_an++),
1544 FILLCHECK_DEADBEEF((unsigned char*)(p + CHUNK_SHIFT),
1545 BUCKET_SIZE_REAL(bucket) + RMAGIC_SZ);
1547 #ifdef IGNORE_SMALL_BAD_FREE
1548 if (bucket >= FIRST_BUCKET_WITH_CHECK)
1550 OV_MAGIC(p, bucket) = MAGIC;
1552 OV_INDEX(p) = bucket;
1556 * Record allocated size of block and
1557 * bound space with magic numbers.
1559 p->ov_rmagic = RMAGIC;
1560 if (bucket <= MAX_SHORT_BUCKET) {
1563 nbytes = size + M_OVERHEAD;
1564 p->ov_size = nbytes - 1;
1565 if ((i = nbytes & (RMAGIC_SZ-1))) {
1567 while (i--) /* nbytes - RMAGIC_SZ is end of alloced area */
1568 ((caddr_t)p + nbytes - RMAGIC_SZ)[i] = RMAGIC_C;
1570 /* Same at RMAGIC_SZ-aligned RMAGIC */
1571 nbytes = (nbytes + RMAGIC_SZ - 1) & ~(RMAGIC_SZ - 1);
1572 ((u_int *)((caddr_t)p + nbytes))[-1] = RMAGIC;
1574 FILL_FEEDADAD((unsigned char *)(p + CHUNK_SHIFT), size);
1576 return ((Malloc_t)(p + CHUNK_SHIFT));
1579 static char *last_sbrk_top;
1580 static char *last_op; /* This arena can be easily extended. */
1581 static MEM_SIZE sbrked_remains;
1583 #ifdef DEBUGGING_MSTATS
1587 struct chunk_chain_s {
1588 struct chunk_chain_s *next;
1591 static struct chunk_chain_s *chunk_chain;
1592 static int n_chunks;
1593 static char max_bucket;
1595 /* Cutoff a piece of one of the chunks in the chain. Prefer smaller chunk. */
1597 get_from_chain(MEM_SIZE size)
1599 struct chunk_chain_s *elt = chunk_chain, **oldp = &chunk_chain;
1600 struct chunk_chain_s **oldgoodp = NULL;
1601 long min_remain = LONG_MAX;
1604 if (elt->size >= size) {
1605 long remains = elt->size - size;
1606 if (remains >= 0 && remains < min_remain) {
1608 min_remain = remains;
1614 oldp = &( elt->next );
1617 if (!oldgoodp) return NULL;
1619 void *ret = *oldgoodp;
1620 struct chunk_chain_s *next = (*oldgoodp)->next;
1622 *oldgoodp = (struct chunk_chain_s *)((char*)ret + size);
1623 (*oldgoodp)->size = min_remain;
1624 (*oldgoodp)->next = next;
1627 void *ret = *oldgoodp;
1628 *oldgoodp = (*oldgoodp)->next;
1635 add_to_chain(void *p, MEM_SIZE size, MEM_SIZE chip)
1637 struct chunk_chain_s *next = chunk_chain;
1638 char *cp = (char*)p;
1641 chunk_chain = (struct chunk_chain_s *)cp;
1642 chunk_chain->size = size - chip;
1643 chunk_chain->next = next;
1648 get_from_bigger_buckets(int bucket, MEM_SIZE size)
1651 static int bucketprice[NBUCKETS];
1652 while (bucket <= max_bucket) {
1653 /* We postpone stealing from bigger buckets until we want it
1655 if (nextf[bucket] && bucketprice[bucket]++ >= price) {
1657 void *ret = (void*)(nextf[bucket] - 1 + CHUNK_SHIFT);
1658 bucketprice[bucket] = 0;
1659 if (((char*)nextf[bucket]) - M_OVERHEAD == last_op) {
1660 last_op = NULL; /* Disable optimization */
1662 nextf[bucket] = nextf[bucket]->ov_next;
1663 #ifdef DEBUGGING_MSTATS
1665 start_slack -= M_OVERHEAD;
1667 add_to_chain(ret, (BUCKET_SIZE_NO_SURPLUS(bucket) +
1668 POW2_OPTIMIZE_SURPLUS(bucket)),
1677 static union overhead *
1678 getpages(MEM_SIZE needed, int *nblksp, int bucket)
1681 /* Need to do (possibly expensive) system call. Try to
1682 optimize it for rare calling. */
1683 MEM_SIZE require = needed - sbrked_remains;
1685 union overhead *ovp;
1688 if (sbrk_goodness > 0) {
1689 if (!last_sbrk_top && require < (MEM_SIZE)FIRST_SBRK)
1690 require = FIRST_SBRK;
1691 else if (require < (MEM_SIZE)MIN_SBRK) require = MIN_SBRK;
1693 if (require < goodsbrk * MIN_SBRK_FRAC1000 / 1000)
1694 require = goodsbrk * MIN_SBRK_FRAC1000 / 1000;
1695 require = ((require - 1 + MIN_SBRK) / MIN_SBRK) * MIN_SBRK;
1702 DEBUG_m(PerlIO_printf(Perl_debug_log,
1703 "sbrk(%ld) for %ld-byte-long arena\n",
1704 (long)require, (long) needed));
1705 cp = (char *)sbrk(require);
1706 #ifdef DEBUGGING_MSTATS
1709 if (cp == last_sbrk_top) {
1710 /* Common case, anything is fine. */
1712 ovp = (union overhead *) (cp - sbrked_remains);
1713 last_op = cp - sbrked_remains;
1714 sbrked_remains = require - (needed - sbrked_remains);
1715 } else if (cp == (char *)-1) { /* no more room! */
1716 ovp = (union overhead *)emergency_sbrk(needed);
1717 if (ovp == (union overhead *)-1)
1719 if (((char*)ovp) > last_op) { /* Cannot happen with current emergency_sbrk() */
1723 } else { /* Non-continuous or first sbrk(). */
1724 long add = sbrked_remains;
1727 if (sbrked_remains) { /* Put rest into chain, we
1728 cannot use it right now. */
1729 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1733 /* Second, check alignment. */
1736 #if !defined(atarist) /* on the atari we dont have to worry about this */
1737 # ifndef I286 /* The sbrk(0) call on the I286 always returns the next segment */
1738 /* WANTED_ALIGNMENT may be more than NEEDED_ALIGNMENT, but this may
1739 improve performance of memory access. */
1740 if (PTR2UV(cp) & (WANTED_ALIGNMENT - 1)) { /* Not aligned. */
1741 slack = WANTED_ALIGNMENT - (PTR2UV(cp) & (WANTED_ALIGNMENT - 1));
1745 #endif /* !atarist */
1748 DEBUG_m(PerlIO_printf(Perl_debug_log,
1749 "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",
1750 (long)add, (long) slack,
1751 (long) sbrked_remains));
1752 newcp = (char *)sbrk(add);
1753 #if defined(DEBUGGING_MSTATS)
1757 if (newcp != cp + require) {
1758 /* Too bad: even rounding sbrk() is not continuous.*/
1759 DEBUG_m(PerlIO_printf(Perl_debug_log,
1760 "failed to fix bad sbrk()\n"));
1764 fatalcroak("panic: Off-page sbrk\n");
1767 if (sbrked_remains) {
1769 #if defined(DEBUGGING_MSTATS)
1770 sbrk_slack += require;
1773 DEBUG_m(PerlIO_printf(Perl_debug_log,
1774 "straight sbrk(%ld)\n",
1776 cp = (char *)sbrk(require);
1777 #ifdef DEBUGGING_MSTATS
1780 if (cp == (char *)-1)
1783 sbrk_goodness = -1; /* Disable optimization!
1784 Continue with not-aligned... */
1787 require += sbrked_remains;
1791 if (last_sbrk_top) {
1792 sbrk_goodness -= SBRK_FAILURE_PRICE;
1795 ovp = (union overhead *) cp;
1797 * Round up to minimum allocation size boundary
1798 * and deduct from block count to reflect.
1801 # if NEEDED_ALIGNMENT > MEM_ALIGNBYTES
1802 if (PTR2UV(ovp) & (NEEDED_ALIGNMENT - 1))
1803 fatalcroak("Misalignment of sbrk()\n");
1806 #ifndef I286 /* Again, this should always be ok on an 80286 */
1807 if (PTR2UV(ovp) & (MEM_ALIGNBYTES - 1)) {
1808 DEBUG_m(PerlIO_printf(Perl_debug_log,
1809 "fixing sbrk(): %d bytes off machine alignment\n",
1810 (int)(PTR2UV(ovp) & (MEM_ALIGNBYTES - 1))));
1811 ovp = INT2PTR(union overhead *,(PTR2UV(ovp) + MEM_ALIGNBYTES) &
1812 (MEM_ALIGNBYTES - 1));
1814 # if defined(DEBUGGING_MSTATS)
1815 /* This is only approx. if TWO_POT_OPTIMIZE: */
1816 sbrk_slack += (1 << (bucket >> BUCKET_POW2_SHIFT));
1820 ; /* Finish "else" */
1821 sbrked_remains = require - needed;
1824 #if !defined(PLAIN_MALLOC) && !defined(NO_FANCY_MALLOC)
1825 emergency_buffer_last_req = 0;
1827 last_sbrk_top = cp + require;
1828 #ifdef DEBUGGING_MSTATS
1829 goodsbrk += require;
1835 getpages_adjacent(MEM_SIZE require)
1837 if (require <= sbrked_remains) {
1838 sbrked_remains -= require;
1842 require -= sbrked_remains;
1843 /* We do not try to optimize sbrks here, we go for place. */
1844 cp = (char*) sbrk(require);
1845 #ifdef DEBUGGING_MSTATS
1847 goodsbrk += require;
1849 if (cp == last_sbrk_top) {
1851 last_sbrk_top = cp + require;
1853 if (cp == (char*)-1) { /* Out of memory */
1854 #ifdef DEBUGGING_MSTATS
1855 goodsbrk -= require;
1859 /* Report the failure: */
1861 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1863 add_to_chain((void*)cp, require, 0);
1864 sbrk_goodness -= SBRK_FAILURE_PRICE;
1876 * Allocate more memory to the indicated bucket.
1879 morecore(register int bucket)
1882 register union overhead *ovp;
1883 register int rnu; /* 2^rnu bytes will be requested */
1884 int nblks; /* become nblks blocks of the desired size */
1885 register MEM_SIZE siz, needed;
1886 static int were_called = 0;
1890 #ifndef NO_PERL_MALLOC_ENV
1892 /* It's the our first time. Initialize ourselves */
1893 were_called = 1; /* Avoid a loop */
1894 if (!MallocCfg[MallocCfg_skip_cfg_env]) {
1895 char *s = getenv("PERL_MALLOC_OPT"), *t = s, *off;
1896 const char *opts = PERL_MALLOC_OPT_CHARS;
1899 while ( t && t[0] && t[1] == '='
1900 && ((off = strchr(opts, *t))) ) {
1904 while (*t <= '9' && *t >= '0')
1905 val = 10*val + *t++ - '0';
1906 if (!*t || *t == ';') {
1907 if (MallocCfg[off - opts] != val)
1909 MallocCfg[off - opts] = val;
1915 write2("Unrecognized part of PERL_MALLOC_OPT: \"");
1920 MallocCfg[MallocCfg_cfg_env_read] = 1;
1924 if (bucket == sizeof(MEM_SIZE)*8*BUCKETS_PER_POW2) {
1926 croak("%s", "Out of memory during ridiculously large request");
1928 if (bucket > max_bucket)
1929 max_bucket = bucket;
1931 rnu = ( (bucket <= (LOG_OF_MIN_ARENA << BUCKET_POW2_SHIFT))
1933 : (bucket >> BUCKET_POW2_SHIFT) );
1934 /* This may be overwritten later: */
1935 nblks = 1 << (rnu - (bucket >> BUCKET_POW2_SHIFT)); /* how many blocks to get */
1936 needed = ((MEM_SIZE)1 << rnu) + POW2_OPTIMIZE_SURPLUS(bucket);
1937 if (nextf[rnu << BUCKET_POW2_SHIFT]) { /* 2048b bucket. */
1938 ovp = nextf[rnu << BUCKET_POW2_SHIFT] - 1 + CHUNK_SHIFT;
1939 nextf[rnu << BUCKET_POW2_SHIFT]
1940 = nextf[rnu << BUCKET_POW2_SHIFT]->ov_next;
1941 #ifdef DEBUGGING_MSTATS
1942 nmalloc[rnu << BUCKET_POW2_SHIFT]--;
1943 start_slack -= M_OVERHEAD;
1945 DEBUG_m(PerlIO_printf(Perl_debug_log,
1946 "stealing %ld bytes from %ld arena\n",
1947 (long) needed, (long) rnu << BUCKET_POW2_SHIFT));
1948 } else if (chunk_chain
1949 && (ovp = (union overhead*) get_from_chain(needed))) {
1950 DEBUG_m(PerlIO_printf(Perl_debug_log,
1951 "stealing %ld bytes from chain\n",
1953 } else if ( (ovp = (union overhead*)
1954 get_from_bigger_buckets((rnu << BUCKET_POW2_SHIFT) + 1,
1956 DEBUG_m(PerlIO_printf(Perl_debug_log,
1957 "stealing %ld bytes from bigger buckets\n",
1959 } else if (needed <= sbrked_remains) {
1960 ovp = (union overhead *)(last_sbrk_top - sbrked_remains);
1961 sbrked_remains -= needed;
1962 last_op = (char*)ovp;
1964 ovp = getpages(needed, &nblks, bucket);
1968 FILL_DEADBEEF((unsigned char*)ovp, needed);
1971 * Add new memory allocated to that on
1972 * free list for this hash bucket.
1974 siz = BUCKET_SIZE_NO_SURPLUS(bucket); /* No surplus if nblks > 1 */
1976 *(u_char*)ovp = bucket; /* Fill index. */
1977 if (bucket <= MAX_PACKED) {
1978 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1979 nblks = N_BLKS(bucket);
1980 # ifdef DEBUGGING_MSTATS
1981 start_slack += BLK_SHIFT(bucket);
1983 } else if (bucket < LOG_OF_MIN_ARENA * BUCKETS_PER_POW2) {
1984 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1985 siz -= sizeof(union overhead);
1986 } else ovp++; /* One chunk per block. */
1987 #endif /* PACK_MALLOC */
1988 nextf[bucket] = ovp;
1989 #ifdef DEBUGGING_MSTATS
1990 nmalloc[bucket] += nblks;
1991 if (bucket > MAX_PACKED) {
1992 start_slack += M_OVERHEAD * nblks;
1996 while (--nblks > 0) {
1997 ovp->ov_next = (union overhead *)((caddr_t)ovp + siz);
1998 ovp = (union overhead *)((caddr_t)ovp + siz);
2000 /* Not all sbrks return zeroed memory.*/
2001 ovp->ov_next = (union overhead *)NULL;
2003 if (bucket == 7*BUCKETS_PER_POW2) { /* Special case, explanation is above. */
2004 union overhead *n_op = nextf[7*BUCKETS_PER_POW2]->ov_next;
2005 nextf[7*BUCKETS_PER_POW2] =
2006 (union overhead *)((caddr_t)nextf[7*BUCKETS_PER_POW2]
2007 - sizeof(union overhead));
2008 nextf[7*BUCKETS_PER_POW2]->ov_next = n_op;
2010 #endif /* !PACK_MALLOC */
2014 Perl_mfree(Malloc_t where)
2017 register MEM_SIZE size;
2018 register union overhead *ovp;
2019 char *cp = (char*)where;
2024 DEBUG_m(PerlIO_printf(Perl_debug_log,
2025 "0x%"UVxf": (%05lu) free\n",
2026 PTR2UV(cp), (unsigned long)(PL_an++)));
2031 if (PTR2UV(cp) & (MEM_ALIGNBYTES - 1))
2032 croak("%s", "wrong alignment in free()");
2034 ovp = (union overhead *)((caddr_t)cp
2035 - sizeof (union overhead) * CHUNK_SHIFT);
2037 bucket = OV_INDEX(ovp);
2039 #ifdef IGNORE_SMALL_BAD_FREE
2040 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
2041 && (OV_MAGIC(ovp, bucket) != MAGIC))
2043 if (OV_MAGIC(ovp, bucket) != MAGIC)
2046 static int bad_free_warn = -1;
2047 if (bad_free_warn == -1) {
2049 char *pbf = PerlEnv_getenv("PERL_BADFREE");
2050 bad_free_warn = (pbf) ? atoi(pbf) : 1;
2058 if (!PERL_IS_ALIVE || !PL_curcop)
2059 Perl_ck_warner_d(aTHX_ packWARN(WARN_MALLOC), "%s free() ignored (RMAGIC, PERL_CORE)",
2060 ovp->ov_rmagic == RMAGIC - 1 ?
2061 "Duplicate" : "Bad");
2064 warn("%s free() ignored (RMAGIC)",
2065 ovp->ov_rmagic == RMAGIC - 1 ? "Duplicate" : "Bad");
2071 if (!PERL_IS_ALIVE || !PL_curcop)
2072 Perl_ck_warner_d(aTHX_ packWARN(WARN_MALLOC), "%s", "Bad free() ignored (PERL_CORE)");
2075 warn("%s", "Bad free() ignored");
2078 return; /* sanity */
2081 ASSERT(ovp->ov_rmagic == RMAGIC, "chunk's head overwrite");
2082 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
2084 MEM_SIZE nbytes = ovp->ov_size + 1;
2086 if ((i = nbytes & (RMAGIC_SZ-1))) {
2088 while (i--) { /* nbytes - RMAGIC_SZ is end of alloced area */
2089 ASSERT(((caddr_t)ovp + nbytes - RMAGIC_SZ)[i] == RMAGIC_C,
2090 "chunk's tail overwrite");
2093 /* Same at RMAGIC_SZ-aligned RMAGIC */
2094 nbytes = (nbytes + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ-1);
2095 ASSERT(((u_int *)((caddr_t)ovp + nbytes))[-1] == RMAGIC,
2096 "chunk's tail overwrite");
2097 FILLCHECK_DEADBEEF((unsigned char*)((caddr_t)ovp + nbytes),
2098 BUCKET_SIZE(OV_INDEX(ovp)) - nbytes);
2100 FILL_DEADBEEF((unsigned char*)(ovp+CHUNK_SHIFT),
2101 BUCKET_SIZE_REAL(OV_INDEX(ovp)) + RMAGIC_SZ);
2102 ovp->ov_rmagic = RMAGIC - 1;
2104 ASSERT(OV_INDEX(ovp) < NBUCKETS, "chunk's head overwrite");
2105 size = OV_INDEX(ovp);
2108 ovp->ov_next = nextf[size];
2113 /* There is no need to do any locking in realloc (with an exception of
2114 trying to grow in place if we are at the end of the chain).
2115 If somebody calls us from a different thread with the same address,
2116 we are sole anyway. */
2119 Perl_realloc(void *mp, size_t nbytes)
2122 register MEM_SIZE onb;
2123 union overhead *ovp;
2126 register int bucket;
2127 int incr; /* 1 if does not fit, -1 if "easily" fits in a
2128 smaller bucket, otherwise 0. */
2129 char *cp = (char*)mp;
2131 #if defined(DEBUGGING) || !defined(PERL_CORE)
2132 MEM_SIZE size = nbytes;
2134 if ((long)nbytes < 0)
2135 croak("%s", "panic: realloc");
2138 BARK_64K_LIMIT("Reallocation",nbytes,size);
2140 return Perl_malloc(nbytes);
2142 ovp = (union overhead *)((caddr_t)cp
2143 - sizeof (union overhead) * CHUNK_SHIFT);
2144 bucket = OV_INDEX(ovp);
2146 #ifdef IGNORE_SMALL_BAD_FREE
2147 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
2148 && (OV_MAGIC(ovp, bucket) != MAGIC))
2150 if (OV_MAGIC(ovp, bucket) != MAGIC)
2153 static int bad_free_warn = -1;
2154 if (bad_free_warn == -1) {
2156 char *pbf = PerlEnv_getenv("PERL_BADFREE");
2157 bad_free_warn = (pbf) ? atoi(pbf) : 1;
2165 if (!PERL_IS_ALIVE || !PL_curcop)
2166 Perl_ck_warner_d(aTHX_ packWARN(WARN_MALLOC), "%srealloc() %signored",
2167 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
2168 ovp->ov_rmagic == RMAGIC - 1
2169 ? "of freed memory " : "");
2172 warn2("%srealloc() %signored",
2173 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
2174 ovp->ov_rmagic == RMAGIC - 1 ? "of freed memory " : "");
2180 if (!PERL_IS_ALIVE || !PL_curcop)
2181 Perl_ck_warner_d(aTHX_ packWARN(WARN_MALLOC), "%s",
2182 "Bad realloc() ignored");
2185 warn("%s", "Bad realloc() ignored");
2188 return NULL; /* sanity */
2191 onb = BUCKET_SIZE_REAL(bucket);
2193 * avoid the copy if same size block.
2194 * We are not aggressive with boundary cases. Note that it might
2195 * (for a small number of cases) give false negative if
2196 * both new size and old one are in the bucket for
2197 * FIRST_BIG_POW2, but the new one is near the lower end.
2199 * We do not try to go to 1.5 times smaller bucket so far.
2201 if (nbytes > onb) incr = 1;
2203 #ifdef DO_NOT_TRY_HARDER_WHEN_SHRINKING
2204 if ( /* This is a little bit pessimal if PACK_MALLOC: */
2205 nbytes > ( (onb >> 1) - M_OVERHEAD )
2206 # ifdef TWO_POT_OPTIMIZE
2207 || (bucket == FIRST_BIG_POW2 && nbytes >= LAST_SMALL_BOUND )
2210 #else /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
2211 prev_bucket = ( (bucket > MAX_PACKED + 1)
2212 ? bucket - BUCKETS_PER_POW2
2214 if (nbytes > BUCKET_SIZE_REAL(prev_bucket))
2215 #endif /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
2219 #ifdef STRESS_REALLOC
2226 * Record new allocated size of block and
2227 * bound space with magic numbers.
2229 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
2230 int i, nb = ovp->ov_size + 1;
2232 if ((i = nb & (RMAGIC_SZ-1))) {
2234 while (i--) { /* nb - RMAGIC_SZ is end of alloced area */
2235 ASSERT(((caddr_t)ovp + nb - RMAGIC_SZ)[i] == RMAGIC_C, "chunk's tail overwrite");
2238 /* Same at RMAGIC_SZ-aligned RMAGIC */
2239 nb = (nb + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ-1);
2240 ASSERT(((u_int *)((caddr_t)ovp + nb))[-1] == RMAGIC,
2241 "chunk's tail overwrite");
2242 FILLCHECK_DEADBEEF((unsigned char*)((caddr_t)ovp + nb),
2243 BUCKET_SIZE(OV_INDEX(ovp)) - nb);
2244 if (nbytes > ovp->ov_size + 1 - M_OVERHEAD)
2245 FILL_FEEDADAD((unsigned char*)cp + ovp->ov_size + 1 - M_OVERHEAD,
2246 nbytes - (ovp->ov_size + 1 - M_OVERHEAD));
2248 FILL_DEADBEEF((unsigned char*)cp + nbytes,
2249 nb - M_OVERHEAD + RMAGIC_SZ - nbytes);
2251 * Convert amount of memory requested into
2252 * closest block size stored in hash buckets
2253 * which satisfies request. Account for
2254 * space used per block for accounting.
2256 nbytes += M_OVERHEAD;
2257 ovp->ov_size = nbytes - 1;
2258 if ((i = nbytes & (RMAGIC_SZ-1))) {
2260 while (i--) /* nbytes - RMAGIC_SZ is end of alloced area */
2261 ((caddr_t)ovp + nbytes - RMAGIC_SZ)[i]
2264 /* Same at RMAGIC_SZ-aligned RMAGIC */
2265 nbytes = (nbytes + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ - 1);
2266 ((u_int *)((caddr_t)ovp + nbytes))[-1] = RMAGIC;
2270 DEBUG_m(PerlIO_printf(Perl_debug_log,
2271 "0x%"UVxf": (%05lu) realloc %ld bytes inplace\n",
2272 PTR2UV(res),(unsigned long)(PL_an++),
2274 } else if (incr == 1 && (cp - M_OVERHEAD == last_op)
2275 && (onb > (1 << LOG_OF_MIN_ARENA))) {
2276 MEM_SIZE require, newarena = nbytes, pow;
2279 POW2_OPTIMIZE_ADJUST(newarena);
2280 newarena = newarena + M_OVERHEAD;
2281 /* newarena = (newarena + 3) &~ 3; */
2282 shiftr = (newarena - 1) >> LOG_OF_MIN_ARENA;
2283 pow = LOG_OF_MIN_ARENA + 1;
2284 /* apart from this loop, this is O(1) */
2285 while (shiftr >>= 1)
2287 newarena = (1 << pow) + POW2_OPTIMIZE_SURPLUS(pow * BUCKETS_PER_POW2);
2288 require = newarena - onb - M_OVERHEAD;
2291 if (cp - M_OVERHEAD == last_op /* We *still* are the last chunk */
2292 && getpages_adjacent(require)) {
2293 #ifdef DEBUGGING_MSTATS
2295 nmalloc[pow * BUCKETS_PER_POW2]++;
2297 if (pow * BUCKETS_PER_POW2 > (MEM_SIZE)max_bucket)
2298 max_bucket = pow * BUCKETS_PER_POW2;
2299 *(cp - M_OVERHEAD) = pow * BUCKETS_PER_POW2; /* Fill index. */
2308 DEBUG_m(PerlIO_printf(Perl_debug_log,
2309 "0x%"UVxf": (%05lu) realloc %ld bytes the hard way\n",
2310 PTR2UV(cp),(unsigned long)(PL_an++),
2312 if ((res = (char*)Perl_malloc(nbytes)) == NULL)
2314 if (cp != res) /* common optimization */
2315 Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char);
2318 return ((Malloc_t)res);
2322 Perl_calloc(register size_t elements, register size_t size)
2324 long sz = elements * size;
2325 Malloc_t p = Perl_malloc(sz);
2328 memset((void*)p, 0, sz);
2334 Perl_strdup(const char *s)
2336 MEM_SIZE l = strlen(s);
2337 char *s1 = (char *)Perl_malloc(l+1);
2339 return (char *)CopyD(s, s1, (MEM_SIZE)(l+1), char);
2344 Perl_putenv(char *a)
2346 /* Sometimes system's putenv conflicts with my_setenv() - this is system
2347 malloc vs Perl's free(). */
2354 while (*val && *val != '=')
2359 if (l < sizeof(buf))
2362 var = (char *)Perl_malloc(l + 1);
2363 Copy(a, var, l, char);
2365 my_setenv(var, val+1);
2373 Perl_malloced_size(void *p)
2375 union overhead * const ovp = (union overhead *)
2376 ((caddr_t)p - sizeof (union overhead) * CHUNK_SHIFT);
2377 const int bucket = OV_INDEX(ovp);
2379 PERL_ARGS_ASSERT_MALLOCED_SIZE;
2382 /* The caller wants to have a complete control over the chunk,
2383 disable the memory checking inside the chunk. */
2384 if (bucket <= MAX_SHORT_BUCKET) {
2385 const MEM_SIZE size = BUCKET_SIZE_REAL(bucket);
2386 ovp->ov_size = size + M_OVERHEAD - 1;
2387 *((u_int *)((caddr_t)ovp + size + M_OVERHEAD - RMAGIC_SZ)) = RMAGIC;
2390 return BUCKET_SIZE_REAL(bucket);
2395 Perl_malloc_good_size(size_t wanted)
2397 return BUCKET_SIZE_REAL(S_ajust_size_and_find_bucket(&wanted));
2400 # ifdef BUCKETS_ROOT2
2401 # define MIN_EVEN_REPORT 6
2403 # define MIN_EVEN_REPORT MIN_BUCKET
2407 Perl_get_mstats(pTHX_ perl_mstats_t *buf, int buflen, int level)
2409 #ifdef DEBUGGING_MSTATS
2411 register union overhead *p;
2412 struct chunk_chain_s* nextchain;
2414 PERL_ARGS_ASSERT_GET_MSTATS;
2416 buf->topbucket = buf->topbucket_ev = buf->topbucket_odd
2417 = buf->totfree = buf->total = buf->total_chain = 0;
2419 buf->minbucket = MIN_BUCKET;
2421 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
2422 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
2426 buf->ntotal[i] = nmalloc[i];
2428 buf->totfree += j * BUCKET_SIZE_REAL(i);
2429 buf->total += nmalloc[i] * BUCKET_SIZE_REAL(i);
2431 i % 2 ? (buf->topbucket_odd = i) : (buf->topbucket_ev = i);
2435 nextchain = chunk_chain;
2437 buf->total_chain += nextchain->size;
2438 nextchain = nextchain->next;
2440 buf->total_sbrk = goodsbrk + sbrk_slack;
2442 buf->sbrk_good = sbrk_goodness;
2443 buf->sbrk_slack = sbrk_slack;
2444 buf->start_slack = start_slack;
2445 buf->sbrked_remains = sbrked_remains;
2447 buf->nbuckets = NBUCKETS;
2449 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
2452 buf->bucket_mem_size[i] = BUCKET_SIZE_NO_SURPLUS(i);
2453 buf->bucket_available_size[i] = BUCKET_SIZE_REAL(i);
2456 #else /* defined DEBUGGING_MSTATS */
2457 PerlIO_printf(Perl_error_log, "perl not compiled with DEBUGGING_MSTATS\n");
2458 #endif /* defined DEBUGGING_MSTATS */
2459 return 0; /* XXX unused */
2462 * mstats - print out statistics about malloc
2464 * Prints two lines of numbers, one showing the length of the free list
2465 * for each size category, the second showing the number of mallocs -
2466 * frees for each size category.
2469 Perl_dump_mstats(pTHX_ const char *s)
2471 #ifdef DEBUGGING_MSTATS
2473 perl_mstats_t buffer;
2477 PERL_ARGS_ASSERT_DUMP_MSTATS;
2481 get_mstats(&buffer, NBUCKETS, 0);
2484 PerlIO_printf(Perl_error_log,
2485 "Memory allocation statistics %s (buckets %"IVdf"(%"IVdf")..%"IVdf"(%"IVdf")\n",
2487 (IV)BUCKET_SIZE_REAL(MIN_BUCKET),
2488 (IV)BUCKET_SIZE_NO_SURPLUS(MIN_BUCKET),
2489 (IV)BUCKET_SIZE_REAL(buffer.topbucket),
2490 (IV)BUCKET_SIZE_NO_SURPLUS(buffer.topbucket));
2491 PerlIO_printf(Perl_error_log, "%8"IVdf" free:", buffer.totfree);
2492 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
2493 PerlIO_printf(Perl_error_log,
2494 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2496 : ((i < 12*BUCKETS_PER_POW2) ? " %3"UVuf : " %"UVuf)),
2499 #ifdef BUCKETS_ROOT2
2500 PerlIO_printf(Perl_error_log, "\n\t ");
2501 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
2502 PerlIO_printf(Perl_error_log,
2503 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2505 : ((i < 12*BUCKETS_PER_POW2) ? " %3"UVuf : " %"UVuf)),
2509 PerlIO_printf(Perl_error_log, "\n%8"IVdf" used:", buffer.total - buffer.totfree);
2510 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
2511 PerlIO_printf(Perl_error_log,
2512 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2514 : ((i < 12*BUCKETS_PER_POW2) ? " %3"IVdf : " %"IVdf)),
2515 buffer.ntotal[i] - buffer.nfree[i]);
2517 #ifdef BUCKETS_ROOT2
2518 PerlIO_printf(Perl_error_log, "\n\t ");
2519 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
2520 PerlIO_printf(Perl_error_log,
2521 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2523 : ((i < 12*BUCKETS_PER_POW2) ? " %3"IVdf : " %"IVdf)),
2524 buffer.ntotal[i] - buffer.nfree[i]);
2527 PerlIO_printf(Perl_error_log, "\nTotal sbrk(): %"IVdf"/%"IVdf":%"IVdf". Odd ends: pad+heads+chain+tail: %"IVdf"+%"IVdf"+%"IVdf"+%"IVdf".\n",
2528 buffer.total_sbrk, buffer.sbrks, buffer.sbrk_good,
2529 buffer.sbrk_slack, buffer.start_slack,
2530 buffer.total_chain, buffer.sbrked_remains);
2531 #else /* DEBUGGING_MSTATS */
2532 PerlIO_printf(Perl_error_log, "%s: perl not compiled with DEBUGGING_MSTATS\n",s);
2533 #endif /* DEBUGGING_MSTATS */
2536 #ifdef USE_PERL_SBRK
2538 # if defined(NeXT) || defined(__NeXT__) || defined(PURIFY)
2539 # define PERL_SBRK_VIA_MALLOC
2542 # ifdef PERL_SBRK_VIA_MALLOC
2544 /* it may seem schizophrenic to use perl's malloc and let it call system */
2545 /* malloc, the reason for that is only the 3.2 version of the OS that had */
2546 /* frequent core dumps within nxzonefreenolock. This sbrk routine put an */
2547 /* end to the cores */
2549 # ifndef SYSTEM_ALLOC
2550 # define SYSTEM_ALLOC(a) malloc(a)
2552 # ifndef SYSTEM_ALLOC_ALIGNMENT
2553 # define SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES
2556 # endif /* PERL_SBRK_VIA_MALLOC */
2558 static IV Perl_sbrk_oldchunk;
2559 static long Perl_sbrk_oldsize;
2561 # define PERLSBRK_32_K (1<<15)
2562 # define PERLSBRK_64_K (1<<16)
2570 if (!size) return 0;
2572 reqsize = size; /* just for the DEBUG_m statement */
2575 size = (size + 0x7ff) & ~0x7ff;
2577 if (size <= Perl_sbrk_oldsize) {
2578 got = Perl_sbrk_oldchunk;
2579 Perl_sbrk_oldchunk += size;
2580 Perl_sbrk_oldsize -= size;
2582 if (size >= PERLSBRK_32_K) {
2585 size = PERLSBRK_64_K;
2588 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2589 size += NEEDED_ALIGNMENT - SYSTEM_ALLOC_ALIGNMENT;
2591 got = (IV)SYSTEM_ALLOC(size);
2592 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2593 got = (got + NEEDED_ALIGNMENT - 1) & ~(NEEDED_ALIGNMENT - 1);
2596 /* Chunk is small, register the rest for future allocs. */
2597 Perl_sbrk_oldchunk = got + reqsize;
2598 Perl_sbrk_oldsize = size - reqsize;
2602 DEBUG_m(PerlIO_printf(Perl_debug_log, "sbrk malloc size %ld (reqsize %ld), left size %ld, give addr 0x%"UVxf"\n",
2603 size, reqsize, Perl_sbrk_oldsize, PTR2UV(got)));
2608 #endif /* ! defined USE_PERL_SBRK */
2612 * c-indentation-style: bsd
2614 * indent-tabs-mode: t
2617 * ex: set ts=8 sts=4 sw=4 noet: