6 Here are some notes on configuring Perl's malloc. (For non-perl
9 There are two macros which serve as bulk disablers of advanced
10 features of this malloc: NO_FANCY_MALLOC, PLAIN_MALLOC (undef by
11 default). Look in the list of default values below to understand
12 their exact effect. Defining NO_FANCY_MALLOC returns malloc.c to the
13 state of the malloc in Perl 5.004. Additionally defining PLAIN_MALLOC
14 returns it to the state as of Perl 5.000.
16 Note that some of the settings below may be ignored in the code based
17 on values of other macros. The PERL_CORE symbol is only defined when
18 perl itself is being compiled (so malloc can make some assumptions
19 about perl's facilities being available to it).
21 Each config option has a short description, followed by its name,
22 default value, and a comment about the default (if applicable). Some
23 options take a precise value, while the others are just boolean.
24 The boolean ones are listed first.
26 # Enable code for an emergency memory pool in $^M. See perlvar.pod
27 # for a description of $^M.
28 PERL_EMERGENCY_SBRK (!PLAIN_MALLOC && PERL_CORE)
30 # Enable code for printing memory statistics.
31 DEBUGGING_MSTATS (!PLAIN_MALLOC && PERL_CORE)
33 # Move allocation info for small buckets into separate areas.
34 # Memory optimization (especially for small allocations, of the
35 # less than 64 bytes). Since perl usually makes a large number
36 # of small allocations, this is usually a win.
37 PACK_MALLOC (!PLAIN_MALLOC && !RCHECK)
39 # Add one page to big powers of two when calculating bucket size.
40 # This is targeted at big allocations, as are common in image
42 TWO_POT_OPTIMIZE !PLAIN_MALLOC
44 # Use intermediate bucket sizes between powers-of-two. This is
45 # generally a memory optimization, and a (small) speed pessimization.
46 BUCKETS_ROOT2 !NO_FANCY_MALLOC
48 # Do not check small deallocations for bad free(). Memory
49 # and speed optimization, error reporting pessimization.
50 IGNORE_SMALL_BAD_FREE (!NO_FANCY_MALLOC && !RCHECK)
52 # Use table lookup to decide in which bucket a given allocation will go.
53 SMALL_BUCKET_VIA_TABLE !NO_FANCY_MALLOC
55 # Use a perl-defined sbrk() instead of the (presumably broken or
56 # missing) system-supplied sbrk().
59 # Use system malloc() (or calloc() etc.) to emulate sbrk(). Normally
60 # only used with broken sbrk()s.
61 PERL_SBRK_VIA_MALLOC undef
63 # Which allocator to use if PERL_SBRK_VIA_MALLOC
64 SYSTEM_ALLOC(a) malloc(a)
66 # Minimal alignment (in bytes, should be a power of 2) of SYSTEM_ALLOC
67 SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES
69 # Disable memory overwrite checking with DEBUGGING. Memory and speed
70 # optimization, error reporting pessimization.
73 # Enable memory overwrite checking with DEBUGGING. Memory and speed
74 # pessimization, error reporting optimization
75 RCHECK (DEBUGGING && !NO_RCHECK)
77 # Failed allocations bigger than this size croak (if
78 # PERL_EMERGENCY_SBRK is enabled) without touching $^M. See
79 # perlvar.pod for a description of $^M.
80 BIG_SIZE (1<<16) # 64K
82 # Starting from this power of two, add an extra page to the
83 # size of the bucket. This enables optimized allocations of sizes
84 # close to powers of 2. Note that the value is indexed at 0.
85 FIRST_BIG_POW2 15 # 32K, 16K is used too often
87 # Estimate of minimal memory footprint. malloc uses this value to
88 # request the most reasonable largest blocks of memory from the system.
91 # Round up sbrk()s to multiples of this.
94 # Round up sbrk()s to multiples of this percent of footprint.
97 # Add this much memory to big powers of two to get the bucket size.
100 # This many sbrk() discontinuities should be tolerated even
101 # from the start without deciding that sbrk() is usually
103 SBRK_ALLOW_FAILURES 3
105 # This many continuous sbrk()s compensate for one discontinuous one.
106 SBRK_FAILURE_PRICE 50
108 # Some configurations may ask for 12-byte-or-so allocations which
109 # require 8-byte alignment (?!). In such situation one needs to
110 # define this to disable 12-byte bucket (will increase memory footprint)
111 STRICT_ALIGNMENT undef
113 This implementation assumes that calling PerlIO_printf() does not
114 result in any memory allocation calls (used during a panic).
119 If used outside of Perl environment, it may be useful to redefine
120 the following macros (listed below with defaults):
122 # Type of address returned by allocation functions
125 # Type of size argument for allocation functions
126 MEM_SIZE unsigned long
131 # Maximal value in LONG
134 # Unsigned integer type big enough to keep a pointer
137 # Type of pointer with 1-byte granularity
140 # Type returned by free()
143 # Very fatal condition reporting function (cannot call any )
144 fatalcroak(arg) write(2,arg,strlen(arg)) + exit(2)
146 # Fatal error reporting function
147 croak(format, arg) warn(idem) + exit(1)
149 # Fatal error reporting function
150 croak2(format, arg1, arg2) warn2(idem) + exit(1)
152 # Error reporting function
153 warn(format, arg) fprintf(stderr, idem)
155 # Error reporting function
156 warn2(format, arg1, arg2) fprintf(stderr, idem)
158 # Locking/unlocking for MT operation
159 MALLOC_LOCK MUTEX_LOCK(&PL_malloc_mutex)
160 MALLOC_UNLOCK MUTEX_UNLOCK(&PL_malloc_mutex)
162 # Locking/unlocking mutex for MT operation
167 #ifndef NO_FANCY_MALLOC
168 # ifndef SMALL_BUCKET_VIA_TABLE
169 # define SMALL_BUCKET_VIA_TABLE
171 # ifndef BUCKETS_ROOT2
172 # define BUCKETS_ROOT2
174 # ifndef IGNORE_SMALL_BAD_FREE
175 # define IGNORE_SMALL_BAD_FREE
179 #ifndef PLAIN_MALLOC /* Bulk enable features */
183 # ifndef TWO_POT_OPTIMIZE
184 # define TWO_POT_OPTIMIZE
186 # if defined(PERL_CORE) && !defined(PERL_EMERGENCY_SBRK)
187 # define PERL_EMERGENCY_SBRK
189 # if defined(PERL_CORE) && !defined(DEBUGGING_MSTATS)
190 # define DEBUGGING_MSTATS
194 #define MIN_BUC_POW2 (sizeof(void*) > 4 ? 3 : 2) /* Allow for 4-byte arena. */
195 #define MIN_BUCKET (MIN_BUC_POW2 * BUCKETS_PER_POW2)
197 #if !(defined(I286) || defined(atarist) || defined(__MINT__))
198 /* take 2k unless the block is bigger than that */
199 # define LOG_OF_MIN_ARENA 11
201 /* take 16k unless the block is bigger than that
202 (80286s like large segments!), probably good on the atari too */
203 # define LOG_OF_MIN_ARENA 14
207 # if defined(DEBUGGING) && !defined(NO_RCHECK)
210 # if defined(RCHECK) && defined(IGNORE_SMALL_BAD_FREE)
211 # undef IGNORE_SMALL_BAD_FREE
214 * malloc.c (Caltech) 2/21/82
215 * Chris Kingsley, kingsley@cit-20.
217 * This is a very fast storage allocator. It allocates blocks of a small
218 * number of different sizes, and keeps free lists of each size. Blocks that
219 * don't exactly fit are passed up to the next larger size. In this
220 * implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long.
221 * If PACK_MALLOC is defined, small blocks are 2^n bytes long.
222 * This is designed for use in a program that uses vast quantities of memory,
223 * but bombs when it runs out.
225 * Modifications Copyright Ilya Zakharevich 1996-99.
227 * Still very quick, but much more thrifty. (Std config is 10% slower
228 * than it was, and takes 67% of old heap size for typical usage.)
230 * Allocations of small blocks are now table-driven to many different
231 * buckets. Sizes of really big buckets are increased to accomodata
232 * common size=power-of-2 blocks. Running-out-of-memory is made into
233 * an exception. Deeply configurable and thread-safe.
239 # define PERL_IN_MALLOC_C
241 # if defined(PERL_IMPLICIT_CONTEXT)
242 # define croak Perl_croak_nocontext
243 # define croak2 Perl_croak_nocontext
244 # define warn Perl_warn_nocontext
245 # define warn2 Perl_warn_nocontext
247 # define croak2 croak
252 # include "../EXTERN.h"
253 # include "../perl.h"
260 # define Malloc_t void *
266 # define MEM_SIZE unsigned long
269 # define LONG_MAX 0x7FFFFFFF
272 # define UV unsigned long
275 # define caddr_t char *
280 # define Copy(s,d,n,t) (void)memcpy((char*)(d),(char*)(s), (n) * sizeof(t))
281 # define PerlEnv_getenv getenv
282 # define PerlIO_printf fprintf
283 # define PerlIO_stderr() stderr
285 # ifndef croak /* make depend */
286 # define croak(mess, arg) (warn((mess), (arg)), exit(1))
288 # ifndef croak2 /* make depend */
289 # define croak2(mess, arg1, arg2) (warn2((mess), (arg1), (arg2)), exit(1))
292 # define warn(mess, arg) fprintf(stderr, (mess), (arg))
295 # define warn2(mess, arg1) fprintf(stderr, (mess), (arg1), (arg2))
307 # define dTHX extern int Perl___notused
308 # define WITH_THX(s) s
310 # ifndef PERL_GET_INTERP
311 # define PERL_GET_INTERP PL_curinterp
314 # define Perl_malloc malloc
317 # define Perl_mfree free
319 # ifndef Perl_realloc
320 # define Perl_realloc realloc
323 # define Perl_calloc calloc
326 # define Perl_strdup strdup
331 # define MUTEX_LOCK(l)
335 # define MUTEX_UNLOCK(l)
339 # define MALLOC_LOCK MUTEX_LOCK(&PL_malloc_mutex)
342 #ifndef MALLOC_UNLOCK
343 # define MALLOC_UNLOCK MUTEX_UNLOCK(&PL_malloc_mutex)
346 # ifndef fatalcroak /* make depend */
347 # define fatalcroak(mess) (write(2, (mess), strlen(mess)), exit(2))
352 # define DEBUG_m(a) \
354 if (PERL_GET_INTERP) { dTHX; if (PL_debug & 128) { a; } } \
358 #ifdef PERL_IMPLICIT_CONTEXT
359 # define PERL_IS_ALIVE aTHX
361 # define PERL_IS_ALIVE TRUE
368 * The memory is broken into "blocks" which occupy multiples of 2K (and
369 * generally speaking, have size "close" to a power of 2). The addresses
370 * of such *unused* blocks are kept in nextf[i] with big enough i. (nextf
371 * is an array of linked lists.) (Addresses of used blocks are not known.)
373 * Moreover, since the algorithm may try to "bite" smaller blocks out
374 * of unused bigger ones, there are also regions of "irregular" size,
375 * managed separately, by a linked list chunk_chain.
377 * The third type of storage is the sbrk()ed-but-not-yet-used space, its
378 * end and size are kept in last_sbrk_top and sbrked_remains.
380 * Growing blocks "in place":
381 * ~~~~~~~~~~~~~~~~~~~~~~~~~
382 * The address of the block with the greatest address is kept in last_op
383 * (if not known, last_op is 0). If it is known that the memory above
384 * last_op is not continuous, or contains a chunk from chunk_chain,
385 * last_op is set to 0.
387 * The chunk with address last_op may be grown by expanding into
388 * sbrk()ed-but-not-yet-used space, or trying to sbrk() more continuous
391 * Management of last_op:
392 * ~~~~~~~~~~~~~~~~~~~~~
394 * free() never changes the boundaries of blocks, so is not relevant.
396 * The only way realloc() may change the boundaries of blocks is if it
397 * grows a block "in place". However, in the case of success such a
398 * chunk is automatically last_op, and it remains last_op. In the case
399 * of failure getpages_adjacent() clears last_op.
401 * malloc() may change blocks by calling morecore() only.
403 * morecore() may create new blocks by:
404 * a) biting pieces from chunk_chain (cannot create one above last_op);
405 * b) biting a piece from an unused block (if block was last_op, this
406 * may create a chunk from chain above last_op, thus last_op is
407 * invalidated in such a case).
408 * c) biting of sbrk()ed-but-not-yet-used space. This creates
409 * a block which is last_op.
410 * d) Allocating new pages by calling getpages();
412 * getpages() creates a new block. It marks last_op at the bottom of
413 * the chunk of memory it returns.
415 * Active pages footprint:
416 * ~~~~~~~~~~~~~~~~~~~~~~
417 * Note that we do not need to traverse the lists in nextf[i], just take
418 * the first element of this list. However, we *need* to traverse the
419 * list in chunk_chain, but most the time it should be a very short one,
420 * so we do not step on a lot of pages we are not going to use.
424 * get_from_bigger_buckets(): forget to increment price => Quite
428 /* I don't much care whether these are defined in sys/types.h--LAW */
430 #define u_char unsigned char
431 #define u_int unsigned int
433 * I removed the definition of u_bigint which appeared to be u_bigint = UV
434 * u_bigint was only used in TWOK_MASKED and TWOK_SHIFT
435 * where I have used PTR2UV. RMB
437 #define u_short unsigned short
439 /* 286 and atarist like big chunks, which gives too much overhead. */
440 #if (defined(RCHECK) || defined(I286) || defined(atarist) || defined(__MINT__)) && defined(PACK_MALLOC)
445 * The description below is applicable if PACK_MALLOC is not defined.
447 * The overhead on a block is at least 4 bytes. When free, this space
448 * contains a pointer to the next free block, and the bottom two bits must
449 * be zero. When in use, the first byte is set to MAGIC, and the second
450 * byte is the size index. The remaining bytes are for alignment.
451 * If range checking is enabled and the size of the block fits
452 * in two bytes, then the top two bytes hold the size of the requested block
453 * plus the range checking words, and the header word MINUS ONE.
456 union overhead *ov_next; /* when free */
457 #if MEM_ALIGNBYTES > 4
458 double strut; /* alignment problems */
461 u_char ovu_index; /* bucket # */
462 u_char ovu_magic; /* magic number */
464 u_short ovu_size; /* actual block size */
465 u_int ovu_rmagic; /* range magic number */
468 #define ov_magic ovu.ovu_magic
469 #define ov_index ovu.ovu_index
470 #define ov_size ovu.ovu_size
471 #define ov_rmagic ovu.ovu_rmagic
474 #define MAGIC 0xff /* magic # on accounting info */
475 #define RMAGIC 0x55555555 /* magic # on range info */
476 #define RMAGIC_C 0x55 /* magic # on range info */
479 # define RSLOP sizeof (u_int)
480 # ifdef TWO_POT_OPTIMIZE
481 # define MAX_SHORT_BUCKET (12 * BUCKETS_PER_POW2)
483 # define MAX_SHORT_BUCKET (13 * BUCKETS_PER_POW2)
489 #if !defined(PACK_MALLOC) && defined(BUCKETS_ROOT2)
490 # undef BUCKETS_ROOT2
494 # define BUCKET_TABLE_SHIFT 2
495 # define BUCKET_POW2_SHIFT 1
496 # define BUCKETS_PER_POW2 2
498 # define BUCKET_TABLE_SHIFT MIN_BUC_POW2
499 # define BUCKET_POW2_SHIFT 0
500 # define BUCKETS_PER_POW2 1
503 #if !defined(MEM_ALIGNBYTES) || ((MEM_ALIGNBYTES > 4) && !defined(STRICT_ALIGNMENT))
504 /* Figure out the alignment of void*. */
509 # define ALIGN_SMALL ((int)((caddr_t)&(((struct aligner*)0)->p)))
511 # define ALIGN_SMALL MEM_ALIGNBYTES
514 #define IF_ALIGN_8(yes,no) ((ALIGN_SMALL>4) ? (yes) : (no))
517 # define MAX_BUCKET_BY_TABLE 13
518 static u_short buck_size[MAX_BUCKET_BY_TABLE + 1] =
520 0, 0, 0, 0, 4, 4, 8, 12, 16, 24, 32, 48, 64, 80,
522 # define BUCKET_SIZE(i) ((i) % 2 ? buck_size[i] : (1 << ((i) >> BUCKET_POW2_SHIFT)))
523 # define BUCKET_SIZE_REAL(i) ((i) <= MAX_BUCKET_BY_TABLE \
525 : ((1 << ((i) >> BUCKET_POW2_SHIFT)) \
527 + POW2_OPTIMIZE_SURPLUS(i)))
529 # define BUCKET_SIZE(i) (1 << ((i) >> BUCKET_POW2_SHIFT))
530 # define BUCKET_SIZE_REAL(i) (BUCKET_SIZE(i) - MEM_OVERHEAD(i) + POW2_OPTIMIZE_SURPLUS(i))
535 /* In this case there are several possible layout of arenas depending
536 * on the size. Arenas are of sizes multiple to 2K, 2K-aligned, and
537 * have a size close to a power of 2.
539 * Arenas of the size >= 4K keep one chunk only. Arenas of size 2K
540 * may keep one chunk or multiple chunks. Here are the possible
543 * # One chunk only, chunksize 2^k + SOMETHING - ALIGN, k >= 11
545 * INDEX MAGIC1 UNUSED CHUNK1
547 * # Multichunk with sanity checking and chunksize 2^k-ALIGN, k>7
549 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 CHUNK2 CHUNK3 ...
551 * # Multichunk with sanity checking and size 2^k-ALIGN, k=7
553 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 UNUSED CHUNK2 CHUNK3 ...
555 * # Multichunk with sanity checking and size up to 80
557 * INDEX UNUSED MAGIC1 UNUSED MAGIC2 UNUSED ... CHUNK1 CHUNK2 CHUNK3 ...
559 * # No sanity check (usually up to 48=byte-long buckets)
560 * INDEX UNUSED CHUNK1 CHUNK2 ...
562 * Above INDEX and MAGIC are one-byte-long. Sizes of UNUSED are
563 * appropriate to keep algorithms simple and memory aligned. INDEX
564 * encodes the size of the chunk, while MAGICn encodes state (used,
565 * free or non-managed-by-us-so-it-indicates-a-bug) of CHUNKn. MAGIC
566 * is used for sanity checking purposes only. SOMETHING is 0 or 4K
567 * (to make size of big CHUNK accomodate allocations for powers of two
570 * [There is no need to alignment between chunks, since C rules ensure
571 * that structs which need 2^k alignment have sizeof which is
572 * divisible by 2^k. Thus as far as the last chunk is aligned at the
573 * end of the arena, and 2K-alignment does not contradict things,
574 * everything is going to be OK for sizes of chunks 2^n and 2^n +
575 * 2^k. Say, 80-bit buckets will be 16-bit aligned, and as far as we
576 * put allocations for requests in 65..80 range, all is fine.
578 * Note, however, that standard malloc() puts more strict
579 * requirements than the above C rules. Moreover, our algorithms of
580 * realloc() may break this idyll, but we suppose that realloc() does
581 * need not change alignment.]
583 * Is very important to make calculation of the offset of MAGICm as
584 * quick as possible, since it is done on each malloc()/free(). In
585 * fact it is so quick that it has quite little effect on the speed of
586 * doing malloc()/free(). [By default] We forego such calculations
587 * for small chunks, but only to save extra 3% of memory, not because
588 * of speed considerations.
590 * Here is the algorithm [which is the same for all the allocations
591 * schemes above], see OV_MAGIC(block,bucket). Let OFFSETm be the
592 * offset of the CHUNKm from the start of ARENA. Then offset of
593 * MAGICm is (OFFSET1 >> SHIFT) + ADDOFFSET. Here SHIFT and ADDOFFSET
594 * are numbers which depend on the size of the chunks only.
596 * Let as check some sanity conditions. Numbers OFFSETm>>SHIFT are
597 * different for all the chunks in the arena if 2^SHIFT is not greater
598 * than size of the chunks in the arena. MAGIC1 will not overwrite
599 * INDEX provided ADDOFFSET is >0 if OFFSET1 < 2^SHIFT. MAGIClast
600 * will not overwrite CHUNK1 if OFFSET1 > (OFFSETlast >> SHIFT) +
603 * Make SHIFT the maximal possible (there is no point in making it
604 * smaller). Since OFFSETlast is 2K - CHUNKSIZE, above restrictions
605 * give restrictions on OFFSET1 and on ADDOFFSET.
607 * In particular, for chunks of size 2^k with k>=6 we can put
608 * ADDOFFSET to be from 0 to 2^k - 2^(11-k), and have
609 * OFFSET1==chunksize. For chunks of size 80 OFFSET1 of 2K%80=48 is
610 * large enough to have ADDOFFSET between 1 and 16 (similarly for 96,
611 * when ADDOFFSET should be 1). In particular, keeping MAGICs for
612 * these sizes gives no additional size penalty.
614 * However, for chunks of size 2^k with k<=5 this gives OFFSET1 >=
615 * ADDOFSET + 2^(11-k). Keeping ADDOFFSET 0 allows for 2^(11-k)-2^(11-2k)
616 * chunks per arena. This is smaller than 2^(11-k) - 1 which are
617 * needed if no MAGIC is kept. [In fact, having a negative ADDOFFSET
618 * would allow for slightly more buckets per arena for k=2,3.]
620 * Similarly, for chunks of size 3/2*2^k with k<=5 MAGICs would span
621 * the area up to 2^(11-k)+ADDOFFSET. For k=4 this give optimal
622 * ADDOFFSET as -7..0. For k=3 ADDOFFSET can go up to 4 (with tiny
623 * savings for negative ADDOFFSET). For k=5 ADDOFFSET can go -1..16
624 * (with no savings for negative values).
626 * In particular, keeping ADDOFFSET 0 for sizes of chunks up to 2^6
627 * leads to tiny pessimizations in case of sizes 4, 8, 12, 24, and
628 * leads to no contradictions except for size=80 (or 96.)
630 * However, it also makes sense to keep no magic for sizes 48 or less.
631 * This is what we do. In this case one needs ADDOFFSET>=1 also for
632 * chunksizes 12, 24, and 48, unless one gets one less chunk per
635 * The algo of OV_MAGIC(block,bucket) keeps ADDOFFSET 0 until
636 * chunksize of 64, then makes it 1.
638 * This allows for an additional optimization: the above scheme leads
639 * to giant overheads for sizes 128 or more (one whole chunk needs to
640 * be sacrifised to keep INDEX). Instead we use chunks not of size
641 * 2^k, but of size 2^k-ALIGN. If we pack these chunks at the end of
642 * the arena, then the beginnings are still in different 2^k-long
643 * sections of the arena if k>=7 for ALIGN==4, and k>=8 if ALIGN=8.
644 * Thus for k>7 the above algo of calculating the offset of the magic
645 * will still give different answers for different chunks. And to
646 * avoid the overrun of MAGIC1 into INDEX, one needs ADDOFFSET of >=1.
647 * In the case k=7 we just move the first chunk an extra ALIGN
648 * backward inside the ARENA (this is done once per arena lifetime,
649 * thus is not a big overhead). */
650 # define MAX_PACKED_POW2 6
651 # define MAX_PACKED (MAX_PACKED_POW2 * BUCKETS_PER_POW2 + BUCKET_POW2_SHIFT)
652 # define MAX_POW2_ALGO ((1<<(MAX_PACKED_POW2 + 1)) - M_OVERHEAD)
653 # define TWOK_MASK ((1<<LOG_OF_MIN_ARENA) - 1)
654 # define TWOK_MASKED(x) (PTR2UV(x) & ~TWOK_MASK)
655 # define TWOK_SHIFT(x) (PTR2UV(x) & TWOK_MASK)
656 # define OV_INDEXp(block) (INT2PTR(u_char*,TWOK_MASKED(block)))
657 # define OV_INDEX(block) (*OV_INDEXp(block))
658 # define OV_MAGIC(block,bucket) (*(OV_INDEXp(block) + \
659 (TWOK_SHIFT(block)>> \
660 (bucket>>BUCKET_POW2_SHIFT)) + \
661 (bucket >= MIN_NEEDS_SHIFT ? 1 : 0)))
662 /* A bucket can have a shift smaller than it size, we need to
663 shift its magic number so it will not overwrite index: */
664 # ifdef BUCKETS_ROOT2
665 # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2 - 1) /* Shift 80 greater than chunk 64. */
667 # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2) /* Shift 128 greater than chunk 32. */
669 # define CHUNK_SHIFT 0
671 /* Number of active buckets of given ordinal. */
672 #ifdef IGNORE_SMALL_BAD_FREE
673 #define FIRST_BUCKET_WITH_CHECK (6 * BUCKETS_PER_POW2) /* 64 */
674 # define N_BLKS(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \
675 ? ((1<<LOG_OF_MIN_ARENA) - 1)/BUCKET_SIZE(bucket) \
678 # define N_BLKS(bucket) n_blks[bucket]
681 static u_short n_blks[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
683 # if BUCKETS_PER_POW2==1
685 (MIN_BUC_POW2==2 ? 384 : 0),
686 224, 120, 62, 31, 16, 8, 4, 2
689 (MIN_BUC_POW2==2 ? 384 : 0), (MIN_BUC_POW2==2 ? 384 : 0), /* 4, 4 */
690 224, 149, 120, 80, 62, 41, 31, 25, 16, 16, 8, 8, 4, 4, 2, 2
694 /* Shift of the first bucket with the given ordinal inside 2K chunk. */
695 #ifdef IGNORE_SMALL_BAD_FREE
696 # define BLK_SHIFT(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \
697 ? ((1<<LOG_OF_MIN_ARENA) \
698 - BUCKET_SIZE(bucket) * N_BLKS(bucket)) \
701 # define BLK_SHIFT(bucket) blk_shift[bucket]
704 static u_short blk_shift[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
706 # if BUCKETS_PER_POW2==1
708 (MIN_BUC_POW2==2 ? 512 : 0),
709 256, 128, 64, 64, /* 8 to 64 */
710 16*sizeof(union overhead),
711 8*sizeof(union overhead),
712 4*sizeof(union overhead),
713 2*sizeof(union overhead),
716 (MIN_BUC_POW2==2 ? 512 : 0), (MIN_BUC_POW2==2 ? 512 : 0),
717 256, 260, 128, 128, 64, 80, 64, 48, /* 8 to 96 */
718 16*sizeof(union overhead), 16*sizeof(union overhead),
719 8*sizeof(union overhead), 8*sizeof(union overhead),
720 4*sizeof(union overhead), 4*sizeof(union overhead),
721 2*sizeof(union overhead), 2*sizeof(union overhead),
725 # define NEEDED_ALIGNMENT 0x800 /* 2k boundaries */
726 # define WANTED_ALIGNMENT 0x800 /* 2k boundaries */
728 #else /* !PACK_MALLOC */
730 # define OV_MAGIC(block,bucket) (block)->ov_magic
731 # define OV_INDEX(block) (block)->ov_index
732 # define CHUNK_SHIFT 1
733 # define MAX_PACKED -1
734 # define NEEDED_ALIGNMENT MEM_ALIGNBYTES
735 # define WANTED_ALIGNMENT 0x400 /* 1k boundaries */
737 #endif /* !PACK_MALLOC */
739 #define M_OVERHEAD (sizeof(union overhead) + RSLOP)
742 # define MEM_OVERHEAD(bucket) \
743 (bucket <= MAX_PACKED ? 0 : M_OVERHEAD)
744 # ifdef SMALL_BUCKET_VIA_TABLE
745 # define START_SHIFTS_BUCKET ((MAX_PACKED_POW2 + 1) * BUCKETS_PER_POW2)
746 # define START_SHIFT MAX_PACKED_POW2
747 # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */
748 # define SIZE_TABLE_MAX 80
750 # define SIZE_TABLE_MAX 64
752 static char bucket_of[] =
754 # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */
755 /* 0 to 15 in 4-byte increments. */
756 (sizeof(void*) > 4 ? 6 : 5), /* 4/8, 5-th bucket for better reports */
758 IF_ALIGN_8(8,7), 8, /* 16/12, 16 */
759 9, 9, 10, 10, /* 24, 32 */
760 11, 11, 11, 11, /* 48 */
761 12, 12, 12, 12, /* 64 */
762 13, 13, 13, 13, /* 80 */
763 13, 13, 13, 13 /* 80 */
764 # else /* !BUCKETS_ROOT2 */
765 /* 0 to 15 in 4-byte increments. */
766 (sizeof(void*) > 4 ? 3 : 2),
772 # endif /* !BUCKETS_ROOT2 */
774 # else /* !SMALL_BUCKET_VIA_TABLE */
775 # define START_SHIFTS_BUCKET MIN_BUCKET
776 # define START_SHIFT (MIN_BUC_POW2 - 1)
777 # endif /* !SMALL_BUCKET_VIA_TABLE */
778 #else /* !PACK_MALLOC */
779 # define MEM_OVERHEAD(bucket) M_OVERHEAD
780 # ifdef SMALL_BUCKET_VIA_TABLE
781 # undef SMALL_BUCKET_VIA_TABLE
783 # define START_SHIFTS_BUCKET MIN_BUCKET
784 # define START_SHIFT (MIN_BUC_POW2 - 1)
785 #endif /* !PACK_MALLOC */
788 * Big allocations are often of the size 2^n bytes. To make them a
789 * little bit better, make blocks of size 2^n+pagesize for big n.
792 #ifdef TWO_POT_OPTIMIZE
794 # ifndef PERL_PAGESIZE
795 # define PERL_PAGESIZE 4096
797 # ifndef FIRST_BIG_POW2
798 # define FIRST_BIG_POW2 15 /* 32K, 16K is used too often. */
800 # define FIRST_BIG_BLOCK (1<<FIRST_BIG_POW2)
801 /* If this value or more, check against bigger blocks. */
802 # define FIRST_BIG_BOUND (FIRST_BIG_BLOCK - M_OVERHEAD)
803 /* If less than this value, goes into 2^n-overhead-block. */
804 # define LAST_SMALL_BOUND ((FIRST_BIG_BLOCK>>1) - M_OVERHEAD)
806 # define POW2_OPTIMIZE_ADJUST(nbytes) \
807 ((nbytes >= FIRST_BIG_BOUND) ? nbytes -= PERL_PAGESIZE : 0)
808 # define POW2_OPTIMIZE_SURPLUS(bucket) \
809 ((bucket >= FIRST_BIG_POW2 * BUCKETS_PER_POW2) ? PERL_PAGESIZE : 0)
811 #else /* !TWO_POT_OPTIMIZE */
812 # define POW2_OPTIMIZE_ADJUST(nbytes)
813 # define POW2_OPTIMIZE_SURPLUS(bucket) 0
814 #endif /* !TWO_POT_OPTIMIZE */
816 #if defined(HAS_64K_LIMIT) && defined(PERL_CORE)
817 # define BARK_64K_LIMIT(what,nbytes,size) \
818 if (nbytes > 0xffff) { \
819 PerlIO_printf(PerlIO_stderr(), \
820 "%s too large: %lx\n", what, size); \
823 #else /* !HAS_64K_LIMIT || !PERL_CORE */
824 # define BARK_64K_LIMIT(what,nbytes,size)
825 #endif /* !HAS_64K_LIMIT || !PERL_CORE */
828 # define MIN_SBRK 2048
832 # define FIRST_SBRK (48*1024)
835 /* Minimal sbrk in percents of what is already alloced. */
836 #ifndef MIN_SBRK_FRAC
837 # define MIN_SBRK_FRAC 3
840 #ifndef SBRK_ALLOW_FAILURES
841 # define SBRK_ALLOW_FAILURES 3
844 #ifndef SBRK_FAILURE_PRICE
845 # define SBRK_FAILURE_PRICE 50
848 static void morecore (register int bucket);
849 # if defined(DEBUGGING)
850 static void botch (char *diag, char *s);
852 static void add_to_chain (void *p, MEM_SIZE size, MEM_SIZE chip);
853 static void* get_from_chain (MEM_SIZE size);
854 static void* get_from_bigger_buckets(int bucket, MEM_SIZE size);
855 static union overhead *getpages (MEM_SIZE needed, int *nblksp, int bucket);
856 static int getpages_adjacent(MEM_SIZE require);
858 #if defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)
861 # define BIG_SIZE (1<<16) /* 64K */
864 #ifdef I_MACH_CTHREADS
866 # define MUTEX_LOCK(m) STMT_START { if (*m) mutex_lock(*m); } STMT_END
868 # define MUTEX_UNLOCK(m) STMT_START { if (*m) mutex_unlock(*m); } STMT_END
872 # define BITS_IN_PTR (8*PTRSIZE)
876 * nextf[i] is the pointer to the next free block of size 2^i. The
877 * smallest allocatable block is 8 bytes. The overhead information
878 * precedes the data area returned to the user.
880 #define NBUCKETS (BITS_IN_PTR*BUCKETS_PER_POW2 + 1)
881 static union overhead *nextf[NBUCKETS];
883 #if defined(PURIFY) && !defined(USE_PERL_SBRK)
884 # define USE_PERL_SBRK
888 #define sbrk(a) Perl_sbrk(a)
889 Malloc_t Perl_sbrk (int size);
891 #ifdef DONT_DECLARE_STD
896 extern Malloc_t sbrk(int);
900 #ifdef DEBUGGING_MSTATS
902 * nmalloc[i] is the difference between the number of mallocs and frees
903 * for a given block size.
905 static u_int nmalloc[NBUCKETS];
906 static u_int sbrk_slack;
907 static u_int start_slack;
908 #else /* !( defined DEBUGGING_MSTATS ) */
909 # define sbrk_slack 0
912 static u_int goodsbrk;
914 static char *emergency_buffer;
915 static MEM_SIZE emergency_buffer_size;
916 static int no_mem; /* 0 if the last request for more memory succeeded.
917 Otherwise the size of the failing request. */
920 emergency_sbrk(MEM_SIZE size)
922 MEM_SIZE rsize = (((size - 1)>>LOG_OF_MIN_ARENA) + 1)<<LOG_OF_MIN_ARENA;
924 if (size >= BIG_SIZE && (!no_mem || (size < no_mem))) {
925 /* Give the possibility to recover, but avoid an infinite cycle. */
928 croak2("Out of memory during \"large\" request for %"UVuf" bytes, total sbrk() is %"UVuf" bytes", (UV)size, (UV)(goodsbrk + sbrk_slack));
931 if (emergency_buffer_size >= rsize) {
932 char *old = emergency_buffer;
934 emergency_buffer_size -= rsize;
935 emergency_buffer += rsize;
939 /* First offense, give a possibility to recover by dieing. */
940 /* No malloc involved here: */
941 GV **gvp = (GV**)hv_fetch(PL_defstash, "^M", 2, 0);
947 if (emergency_buffer_size) {
948 add_to_chain(emergency_buffer, emergency_buffer_size, 0);
949 emergency_buffer_size = 0;
950 emergency_buffer = Nullch;
953 if (!gvp) gvp = (GV**)hv_fetch(PL_defstash, "\015", 1, 0);
954 if (!gvp || !(sv = GvSV(*gvp)) || !SvPOK(sv)
955 || (SvLEN(sv) < (1<<LOG_OF_MIN_ARENA) - M_OVERHEAD)) {
958 return (char *)-1; /* Now die die die... */
960 /* Got it, now detach SvPV: */
962 /* Check alignment: */
963 if ((PTR2UV(pv) - sizeof(union overhead)) & (NEEDED_ALIGNMENT - 1)) {
964 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
965 return (char *)-1; /* die die die */
968 emergency_buffer = pv - sizeof(union overhead);
969 emergency_buffer_size = malloced_size(pv) + M_OVERHEAD;
972 SvCUR(sv) = SvLEN(sv) = 0;
976 croak("Out of memory during request for %"UVuf" bytes, total sbrk() is %"UVuf" bytes", (UV)size, (UV)(goodsbrk + sbrk_slack));
981 #else /* !(defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)) */
982 # define emergency_sbrk(size) -1
983 #endif /* !(defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)) */
987 #define ASSERT(p,diag) if (!(p)) botch(diag,STRINGIFY(p)); else
989 botch(char *diag, char *s)
992 PerlIO_printf(PerlIO_stderr(), "assertion botched (%s?): %s\n", diag, s);
996 #define ASSERT(p, diag)
1000 Perl_malloc(register size_t nbytes)
1002 register union overhead *p;
1003 register int bucket;
1004 register MEM_SIZE shiftr;
1006 #if defined(DEBUGGING) || defined(RCHECK)
1007 MEM_SIZE size = nbytes;
1010 BARK_64K_LIMIT("Allocation",nbytes,nbytes);
1012 if ((long)nbytes < 0)
1013 croak("%s", "panic: malloc");
1017 * Convert amount of memory requested into
1018 * closest block size stored in hash buckets
1019 * which satisfies request. Account for
1020 * space used per block for accounting.
1023 # ifdef SMALL_BUCKET_VIA_TABLE
1025 bucket = MIN_BUCKET;
1026 else if (nbytes <= SIZE_TABLE_MAX) {
1027 bucket = bucket_of[(nbytes - 1) >> BUCKET_TABLE_SHIFT];
1032 if (nbytes <= MAX_POW2_ALGO) goto do_shifts;
1037 POW2_OPTIMIZE_ADJUST(nbytes);
1038 nbytes += M_OVERHEAD;
1039 nbytes = (nbytes + 3) &~ 3;
1041 shiftr = (nbytes - 1) >> START_SHIFT;
1042 bucket = START_SHIFTS_BUCKET;
1043 /* apart from this loop, this is O(1) */
1044 while (shiftr >>= 1)
1045 bucket += BUCKETS_PER_POW2;
1049 * If nothing in hash bucket right now,
1050 * request more memory from the system.
1052 if (nextf[bucket] == NULL)
1054 if ((p = nextf[bucket]) == NULL) {
1061 char *eb = buff + sizeof(buff) - 1;
1065 PerlIO_puts(PerlIO_stderr(),"Out of memory during request for ");
1066 #if defined(DEBUGGING) || defined(RCHECK)
1071 *--s = '0' + (n % 10);
1073 PerlIO_puts(PerlIO_stderr(),s);
1074 PerlIO_puts(PerlIO_stderr()," bytes, total sbrk() is ");
1076 n = goodsbrk + sbrk_slack;
1078 *--s = '0' + (n % 10);
1080 PerlIO_puts(PerlIO_stderr(),s);
1081 PerlIO_puts(PerlIO_stderr()," bytes!\n");
1089 DEBUG_m(PerlIO_printf(Perl_debug_log,
1090 "0x%"UVxf": (%05lu) malloc %ld bytes\n",
1091 PTR2UV(p+1), (unsigned long)(PL_an++),
1094 /* remove from linked list */
1096 if ((PTR2UV(p)) & (MEM_ALIGNBYTES - 1)) {
1098 PerlIO_printf(PerlIO_stderr(),
1099 "Unaligned pointer in the free chain 0x%"UVxf"\n",
1102 if ((PTR2UV(p->ov_next)) & (MEM_ALIGNBYTES - 1)) {
1104 PerlIO_printf(PerlIO_stderr(),
1105 "Unaligned `next' pointer in the free "
1106 "chain 0x%"UVxf" at 0x%"UVxf"\n",
1107 PTR2UV(p->ov_next), PTR2UV(p));
1110 nextf[bucket] = p->ov_next;
1114 #ifdef IGNORE_SMALL_BAD_FREE
1115 if (bucket >= FIRST_BUCKET_WITH_CHECK)
1117 OV_MAGIC(p, bucket) = MAGIC;
1119 OV_INDEX(p) = bucket;
1123 * Record allocated size of block and
1124 * bound space with magic numbers.
1126 p->ov_rmagic = RMAGIC;
1127 if (bucket <= MAX_SHORT_BUCKET) {
1130 nbytes = size + M_OVERHEAD;
1131 p->ov_size = nbytes - 1;
1132 if ((i = nbytes & 3)) {
1135 *((char *)((caddr_t)p + nbytes - RSLOP + i)) = RMAGIC_C;
1137 nbytes = (nbytes + 3) &~ 3;
1138 *((u_int *)((caddr_t)p + nbytes - RSLOP)) = RMAGIC;
1141 return ((Malloc_t)(p + CHUNK_SHIFT));
1144 static char *last_sbrk_top;
1145 static char *last_op; /* This arena can be easily extended. */
1146 static int sbrked_remains;
1147 static int sbrk_good = SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE;
1149 #ifdef DEBUGGING_MSTATS
1153 struct chunk_chain_s {
1154 struct chunk_chain_s *next;
1157 static struct chunk_chain_s *chunk_chain;
1158 static int n_chunks;
1159 static char max_bucket;
1161 /* Cutoff a piece of one of the chunks in the chain. Prefer smaller chunk. */
1163 get_from_chain(MEM_SIZE size)
1165 struct chunk_chain_s *elt = chunk_chain, **oldp = &chunk_chain;
1166 struct chunk_chain_s **oldgoodp = NULL;
1167 long min_remain = LONG_MAX;
1170 if (elt->size >= size) {
1171 long remains = elt->size - size;
1172 if (remains >= 0 && remains < min_remain) {
1174 min_remain = remains;
1180 oldp = &( elt->next );
1183 if (!oldgoodp) return NULL;
1185 void *ret = *oldgoodp;
1186 struct chunk_chain_s *next = (*oldgoodp)->next;
1188 *oldgoodp = (struct chunk_chain_s *)((char*)ret + size);
1189 (*oldgoodp)->size = min_remain;
1190 (*oldgoodp)->next = next;
1193 void *ret = *oldgoodp;
1194 *oldgoodp = (*oldgoodp)->next;
1201 add_to_chain(void *p, MEM_SIZE size, MEM_SIZE chip)
1203 struct chunk_chain_s *next = chunk_chain;
1204 char *cp = (char*)p;
1207 chunk_chain = (struct chunk_chain_s *)cp;
1208 chunk_chain->size = size - chip;
1209 chunk_chain->next = next;
1214 get_from_bigger_buckets(int bucket, MEM_SIZE size)
1217 static int bucketprice[NBUCKETS];
1218 while (bucket <= max_bucket) {
1219 /* We postpone stealing from bigger buckets until we want it
1221 if (nextf[bucket] && bucketprice[bucket]++ >= price) {
1223 void *ret = (void*)(nextf[bucket] - 1 + CHUNK_SHIFT);
1224 bucketprice[bucket] = 0;
1225 if (((char*)nextf[bucket]) - M_OVERHEAD == last_op) {
1226 last_op = NULL; /* Disable optimization */
1228 nextf[bucket] = nextf[bucket]->ov_next;
1229 #ifdef DEBUGGING_MSTATS
1231 start_slack -= M_OVERHEAD;
1233 add_to_chain(ret, (BUCKET_SIZE(bucket) +
1234 POW2_OPTIMIZE_SURPLUS(bucket)),
1243 static union overhead *
1244 getpages(MEM_SIZE needed, int *nblksp, int bucket)
1246 /* Need to do (possibly expensive) system call. Try to
1247 optimize it for rare calling. */
1248 MEM_SIZE require = needed - sbrked_remains;
1250 union overhead *ovp;
1253 if (sbrk_good > 0) {
1254 if (!last_sbrk_top && require < FIRST_SBRK)
1255 require = FIRST_SBRK;
1256 else if (require < MIN_SBRK) require = MIN_SBRK;
1258 if (require < goodsbrk * MIN_SBRK_FRAC / 100)
1259 require = goodsbrk * MIN_SBRK_FRAC / 100;
1260 require = ((require - 1 + MIN_SBRK) / MIN_SBRK) * MIN_SBRK;
1267 DEBUG_m(PerlIO_printf(Perl_debug_log,
1268 "sbrk(%ld) for %ld-byte-long arena\n",
1269 (long)require, (long) needed));
1270 cp = (char *)sbrk(require);
1271 #ifdef DEBUGGING_MSTATS
1274 if (cp == last_sbrk_top) {
1275 /* Common case, anything is fine. */
1277 ovp = (union overhead *) (cp - sbrked_remains);
1278 last_op = cp - sbrked_remains;
1279 sbrked_remains = require - (needed - sbrked_remains);
1280 } else if (cp == (char *)-1) { /* no more room! */
1281 ovp = (union overhead *)emergency_sbrk(needed);
1282 if (ovp == (union overhead *)-1)
1284 if (((char*)ovp) > last_op) { /* Cannot happen with current emergency_sbrk() */
1288 } else { /* Non-continuous or first sbrk(). */
1289 long add = sbrked_remains;
1292 if (sbrked_remains) { /* Put rest into chain, we
1293 cannot use it right now. */
1294 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1298 /* Second, check alignment. */
1301 #if !defined(atarist) && !defined(__MINT__) /* on the atari we dont have to worry about this */
1302 # ifndef I286 /* The sbrk(0) call on the I286 always returns the next segment */
1303 /* WANTED_ALIGNMENT may be more than NEEDED_ALIGNMENT, but this may
1304 improve performance of memory access. */
1305 if (PTR2UV(cp) & (WANTED_ALIGNMENT - 1)) { /* Not aligned. */
1306 slack = WANTED_ALIGNMENT - (PTR2UV(cp) & (WANTED_ALIGNMENT - 1));
1310 #endif /* !atarist && !MINT */
1313 DEBUG_m(PerlIO_printf(Perl_debug_log,
1314 "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",
1315 (long)add, (long) slack,
1316 (long) sbrked_remains));
1317 newcp = (char *)sbrk(add);
1318 #if defined(DEBUGGING_MSTATS)
1322 if (newcp != cp + require) {
1323 /* Too bad: even rounding sbrk() is not continuous.*/
1324 DEBUG_m(PerlIO_printf(Perl_debug_log,
1325 "failed to fix bad sbrk()\n"));
1329 fatalcroak("panic: Off-page sbrk\n");
1332 if (sbrked_remains) {
1334 #if defined(DEBUGGING_MSTATS)
1335 sbrk_slack += require;
1338 DEBUG_m(PerlIO_printf(Perl_debug_log,
1339 "straight sbrk(%ld)\n",
1341 cp = (char *)sbrk(require);
1342 #ifdef DEBUGGING_MSTATS
1345 if (cp == (char *)-1)
1348 sbrk_good = -1; /* Disable optimization!
1349 Continue with not-aligned... */
1352 require += sbrked_remains;
1356 if (last_sbrk_top) {
1357 sbrk_good -= SBRK_FAILURE_PRICE;
1360 ovp = (union overhead *) cp;
1362 * Round up to minimum allocation size boundary
1363 * and deduct from block count to reflect.
1366 # if NEEDED_ALIGNMENT > MEM_ALIGNBYTES
1367 if (PTR2UV(ovp) & (NEEDED_ALIGNMENT - 1))
1368 fatalcroak("Misalignment of sbrk()\n");
1371 #ifndef I286 /* Again, this should always be ok on an 80286 */
1372 if (PTR2UV(ovp) & (MEM_ALIGNBYTES - 1)) {
1373 DEBUG_m(PerlIO_printf(Perl_debug_log,
1374 "fixing sbrk(): %d bytes off machine alignement\n",
1375 (int)(PTR2UV(ovp) & (MEM_ALIGNBYTES - 1))));
1376 ovp = INT2PTR(union overhead *,(PTR2UV(ovp) + MEM_ALIGNBYTES) &
1377 (MEM_ALIGNBYTES - 1));
1379 # if defined(DEBUGGING_MSTATS)
1380 /* This is only approx. if TWO_POT_OPTIMIZE: */
1381 sbrk_slack += (1 << (bucket >> BUCKET_POW2_SHIFT));
1385 ; /* Finish `else' */
1386 sbrked_remains = require - needed;
1390 last_sbrk_top = cp + require;
1391 #ifdef DEBUGGING_MSTATS
1392 goodsbrk += require;
1398 getpages_adjacent(MEM_SIZE require)
1400 if (require <= sbrked_remains) {
1401 sbrked_remains -= require;
1405 require -= sbrked_remains;
1406 /* We do not try to optimize sbrks here, we go for place. */
1407 cp = (char*) sbrk(require);
1408 #ifdef DEBUGGING_MSTATS
1410 goodsbrk += require;
1412 if (cp == last_sbrk_top) {
1414 last_sbrk_top = cp + require;
1416 if (cp == (char*)-1) { /* Out of memory */
1417 #ifdef DEBUGGING_MSTATS
1418 goodsbrk -= require;
1422 /* Report the failure: */
1424 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1426 add_to_chain((void*)cp, require, 0);
1427 sbrk_good -= SBRK_FAILURE_PRICE;
1439 * Allocate more memory to the indicated bucket.
1442 morecore(register int bucket)
1444 register union overhead *ovp;
1445 register int rnu; /* 2^rnu bytes will be requested */
1446 int nblks; /* become nblks blocks of the desired size */
1447 register MEM_SIZE siz, needed;
1451 if (bucket == sizeof(MEM_SIZE)*8*BUCKETS_PER_POW2) {
1453 croak("%s", "Out of memory during ridiculously large request");
1455 if (bucket > max_bucket)
1456 max_bucket = bucket;
1458 rnu = ( (bucket <= (LOG_OF_MIN_ARENA << BUCKET_POW2_SHIFT))
1460 : (bucket >> BUCKET_POW2_SHIFT) );
1461 /* This may be overwritten later: */
1462 nblks = 1 << (rnu - (bucket >> BUCKET_POW2_SHIFT)); /* how many blocks to get */
1463 needed = ((MEM_SIZE)1 << rnu) + POW2_OPTIMIZE_SURPLUS(bucket);
1464 if (nextf[rnu << BUCKET_POW2_SHIFT]) { /* 2048b bucket. */
1465 ovp = nextf[rnu << BUCKET_POW2_SHIFT] - 1 + CHUNK_SHIFT;
1466 nextf[rnu << BUCKET_POW2_SHIFT]
1467 = nextf[rnu << BUCKET_POW2_SHIFT]->ov_next;
1468 #ifdef DEBUGGING_MSTATS
1469 nmalloc[rnu << BUCKET_POW2_SHIFT]--;
1470 start_slack -= M_OVERHEAD;
1472 DEBUG_m(PerlIO_printf(Perl_debug_log,
1473 "stealing %ld bytes from %ld arena\n",
1474 (long) needed, (long) rnu << BUCKET_POW2_SHIFT));
1475 } else if (chunk_chain
1476 && (ovp = (union overhead*) get_from_chain(needed))) {
1477 DEBUG_m(PerlIO_printf(Perl_debug_log,
1478 "stealing %ld bytes from chain\n",
1480 } else if ( (ovp = (union overhead*)
1481 get_from_bigger_buckets((rnu << BUCKET_POW2_SHIFT) + 1,
1483 DEBUG_m(PerlIO_printf(Perl_debug_log,
1484 "stealing %ld bytes from bigger buckets\n",
1486 } else if (needed <= sbrked_remains) {
1487 ovp = (union overhead *)(last_sbrk_top - sbrked_remains);
1488 sbrked_remains -= needed;
1489 last_op = (char*)ovp;
1491 ovp = getpages(needed, &nblks, bucket);
1497 * Add new memory allocated to that on
1498 * free list for this hash bucket.
1500 siz = BUCKET_SIZE(bucket);
1502 *(u_char*)ovp = bucket; /* Fill index. */
1503 if (bucket <= MAX_PACKED) {
1504 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1505 nblks = N_BLKS(bucket);
1506 # ifdef DEBUGGING_MSTATS
1507 start_slack += BLK_SHIFT(bucket);
1509 } else if (bucket < LOG_OF_MIN_ARENA * BUCKETS_PER_POW2) {
1510 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1511 siz -= sizeof(union overhead);
1512 } else ovp++; /* One chunk per block. */
1513 #endif /* PACK_MALLOC */
1514 nextf[bucket] = ovp;
1515 #ifdef DEBUGGING_MSTATS
1516 nmalloc[bucket] += nblks;
1517 if (bucket > MAX_PACKED) {
1518 start_slack += M_OVERHEAD * nblks;
1521 while (--nblks > 0) {
1522 ovp->ov_next = (union overhead *)((caddr_t)ovp + siz);
1523 ovp = (union overhead *)((caddr_t)ovp + siz);
1525 /* Not all sbrks return zeroed memory.*/
1526 ovp->ov_next = (union overhead *)NULL;
1528 if (bucket == 7*BUCKETS_PER_POW2) { /* Special case, explanation is above. */
1529 union overhead *n_op = nextf[7*BUCKETS_PER_POW2]->ov_next;
1530 nextf[7*BUCKETS_PER_POW2] =
1531 (union overhead *)((caddr_t)nextf[7*BUCKETS_PER_POW2]
1532 - sizeof(union overhead));
1533 nextf[7*BUCKETS_PER_POW2]->ov_next = n_op;
1535 #endif /* !PACK_MALLOC */
1539 Perl_mfree(void *mp)
1541 register MEM_SIZE size;
1542 register union overhead *ovp;
1543 char *cp = (char*)mp;
1548 DEBUG_m(PerlIO_printf(Perl_debug_log,
1549 "0x%"UVxf": (%05lu) free\n",
1550 PTR2UV(cp), (unsigned long)(PL_an++)));
1554 ovp = (union overhead *)((caddr_t)cp
1555 - sizeof (union overhead) * CHUNK_SHIFT);
1557 bucket = OV_INDEX(ovp);
1559 #ifdef IGNORE_SMALL_BAD_FREE
1560 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
1561 && (OV_MAGIC(ovp, bucket) != MAGIC))
1563 if (OV_MAGIC(ovp, bucket) != MAGIC)
1566 static int bad_free_warn = -1;
1567 if (bad_free_warn == -1) {
1569 char *pbf = PerlEnv_getenv("PERL_BADFREE");
1570 bad_free_warn = (pbf) ? atoi(pbf) : 1;
1578 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1579 Perl_warner(aTHX_ WARN_MALLOC, "%s free() ignored",
1580 ovp->ov_rmagic == RMAGIC - 1 ?
1581 "Duplicate" : "Bad");
1584 warn("%s free() ignored",
1585 ovp->ov_rmagic == RMAGIC - 1 ? "Duplicate" : "Bad");
1591 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1592 Perl_warner(aTHX_ WARN_MALLOC, "%s", "Bad free() ignored");
1595 warn("%s", "Bad free() ignored");
1598 return; /* sanity */
1601 ASSERT(ovp->ov_rmagic == RMAGIC, "chunk's head overwrite");
1602 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
1604 MEM_SIZE nbytes = ovp->ov_size + 1;
1606 if ((i = nbytes & 3)) {
1609 ASSERT(*((char *)((caddr_t)ovp + nbytes - RSLOP + i))
1610 == RMAGIC_C, "chunk's tail overwrite");
1613 nbytes = (nbytes + 3) &~ 3;
1614 ASSERT(*(u_int *)((caddr_t)ovp + nbytes - RSLOP) == RMAGIC, "chunk's tail overwrite");
1616 ovp->ov_rmagic = RMAGIC - 1;
1618 ASSERT(OV_INDEX(ovp) < NBUCKETS, "chunk's head overwrite");
1619 size = OV_INDEX(ovp);
1622 ovp->ov_next = nextf[size];
1627 /* There is no need to do any locking in realloc (with an exception of
1628 trying to grow in place if we are at the end of the chain).
1629 If somebody calls us from a different thread with the same address,
1630 we are sole anyway. */
1633 Perl_realloc(void *mp, size_t nbytes)
1635 register MEM_SIZE onb;
1636 union overhead *ovp;
1639 register int bucket;
1640 int incr; /* 1 if does not fit, -1 if "easily" fits in a
1641 smaller bucket, otherwise 0. */
1642 char *cp = (char*)mp;
1644 #if defined(DEBUGGING) || !defined(PERL_CORE)
1645 MEM_SIZE size = nbytes;
1647 if ((long)nbytes < 0)
1648 croak("%s", "panic: realloc");
1651 BARK_64K_LIMIT("Reallocation",nbytes,size);
1653 return Perl_malloc(nbytes);
1655 ovp = (union overhead *)((caddr_t)cp
1656 - sizeof (union overhead) * CHUNK_SHIFT);
1657 bucket = OV_INDEX(ovp);
1659 #ifdef IGNORE_SMALL_BAD_FREE
1660 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
1661 && (OV_MAGIC(ovp, bucket) != MAGIC))
1663 if (OV_MAGIC(ovp, bucket) != MAGIC)
1666 static int bad_free_warn = -1;
1667 if (bad_free_warn == -1) {
1669 char *pbf = PerlEnv_getenv("PERL_BADFREE");
1670 bad_free_warn = (pbf) ? atoi(pbf) : 1;
1678 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1679 Perl_warner(aTHX_ WARN_MALLOC, "%srealloc() %signored",
1680 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
1681 ovp->ov_rmagic == RMAGIC - 1
1682 ? "of freed memory " : "");
1685 warn("%srealloc() %signored",
1686 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
1687 ovp->ov_rmagic == RMAGIC - 1 ? "of freed memory " : "");
1693 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1694 Perl_warner(aTHX_ WARN_MALLOC, "%s",
1695 "Bad realloc() ignored");
1698 warn("%s", "Bad realloc() ignored");
1701 return Nullch; /* sanity */
1704 onb = BUCKET_SIZE_REAL(bucket);
1706 * avoid the copy if same size block.
1707 * We are not agressive with boundary cases. Note that it might
1708 * (for a small number of cases) give false negative if
1709 * both new size and old one are in the bucket for
1710 * FIRST_BIG_POW2, but the new one is near the lower end.
1712 * We do not try to go to 1.5 times smaller bucket so far.
1714 if (nbytes > onb) incr = 1;
1716 #ifdef DO_NOT_TRY_HARDER_WHEN_SHRINKING
1717 if ( /* This is a little bit pessimal if PACK_MALLOC: */
1718 nbytes > ( (onb >> 1) - M_OVERHEAD )
1719 # ifdef TWO_POT_OPTIMIZE
1720 || (bucket == FIRST_BIG_POW2 && nbytes >= LAST_SMALL_BOUND )
1723 #else /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
1724 prev_bucket = ( (bucket > MAX_PACKED + 1)
1725 ? bucket - BUCKETS_PER_POW2
1727 if (nbytes > BUCKET_SIZE_REAL(prev_bucket))
1728 #endif /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
1732 #ifdef STRESS_REALLOC
1739 * Record new allocated size of block and
1740 * bound space with magic numbers.
1742 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
1743 int i, nb = ovp->ov_size + 1;
1748 ASSERT(*((char *)((caddr_t)ovp + nb - RSLOP + i)) == RMAGIC_C, "chunk's tail overwrite");
1752 ASSERT(*(u_int *)((caddr_t)ovp + nb - RSLOP) == RMAGIC, "chunk's tail overwrite");
1754 * Convert amount of memory requested into
1755 * closest block size stored in hash buckets
1756 * which satisfies request. Account for
1757 * space used per block for accounting.
1759 nbytes += M_OVERHEAD;
1760 ovp->ov_size = nbytes - 1;
1761 if ((i = nbytes & 3)) {
1764 *((char *)((caddr_t)ovp + nbytes - RSLOP + i))
1767 nbytes = (nbytes + 3) &~ 3;
1768 *((u_int *)((caddr_t)ovp + nbytes - RSLOP)) = RMAGIC;
1772 DEBUG_m(PerlIO_printf(Perl_debug_log,
1773 "0x%"UVxf": (%05lu) realloc %ld bytes inplace\n",
1774 PTR2UV(res),(unsigned long)(PL_an++),
1776 } else if (incr == 1 && (cp - M_OVERHEAD == last_op)
1777 && (onb > (1 << LOG_OF_MIN_ARENA))) {
1778 MEM_SIZE require, newarena = nbytes, pow;
1781 POW2_OPTIMIZE_ADJUST(newarena);
1782 newarena = newarena + M_OVERHEAD;
1783 /* newarena = (newarena + 3) &~ 3; */
1784 shiftr = (newarena - 1) >> LOG_OF_MIN_ARENA;
1785 pow = LOG_OF_MIN_ARENA + 1;
1786 /* apart from this loop, this is O(1) */
1787 while (shiftr >>= 1)
1789 newarena = (1 << pow) + POW2_OPTIMIZE_SURPLUS(pow * BUCKETS_PER_POW2);
1790 require = newarena - onb - M_OVERHEAD;
1793 if (cp - M_OVERHEAD == last_op /* We *still* are the last chunk */
1794 && getpages_adjacent(require)) {
1795 #ifdef DEBUGGING_MSTATS
1797 nmalloc[pow * BUCKETS_PER_POW2]++;
1799 *(cp - M_OVERHEAD) = pow * BUCKETS_PER_POW2; /* Fill index. */
1808 DEBUG_m(PerlIO_printf(Perl_debug_log,
1809 "0x%"UVxf": (%05lu) realloc %ld bytes the hard way\n",
1810 PTR2UV(cp),(unsigned long)(PL_an++),
1812 if ((res = (char*)Perl_malloc(nbytes)) == NULL)
1814 if (cp != res) /* common optimization */
1815 Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char);
1818 return ((Malloc_t)res);
1822 Perl_calloc(register size_t elements, register size_t size)
1824 long sz = elements * size;
1825 Malloc_t p = Perl_malloc(sz);
1828 memset((void*)p, 0, sz);
1834 Perl_strdup(const char *s)
1836 MEM_SIZE l = strlen(s);
1837 char *s1 = (char *)Perl_malloc(l+1);
1839 Copy(s, s1, (MEM_SIZE)(l+1), char);
1845 Perl_putenv(char *a)
1847 /* Sometimes system's putenv conflicts with my_setenv() - this is system
1848 malloc vs Perl's free(). */
1855 while (*val && *val != '=')
1860 if (l < sizeof(buf))
1863 var = Perl_malloc(l + 1);
1864 Copy(a, var, l, char);
1866 my_setenv(var, val+1);
1874 Perl_malloced_size(void *p)
1876 union overhead *ovp = (union overhead *)
1877 ((caddr_t)p - sizeof (union overhead) * CHUNK_SHIFT);
1878 int bucket = OV_INDEX(ovp);
1880 /* The caller wants to have a complete control over the chunk,
1881 disable the memory checking inside the chunk. */
1882 if (bucket <= MAX_SHORT_BUCKET) {
1883 MEM_SIZE size = BUCKET_SIZE_REAL(bucket);
1884 ovp->ov_size = size + M_OVERHEAD - 1;
1885 *((u_int *)((caddr_t)ovp + size + M_OVERHEAD - RSLOP)) = RMAGIC;
1888 return BUCKET_SIZE_REAL(bucket);
1891 # ifdef BUCKETS_ROOT2
1892 # define MIN_EVEN_REPORT 6
1894 # define MIN_EVEN_REPORT MIN_BUCKET
1898 Perl_get_mstats(pTHX_ perl_mstats_t *buf, int buflen, int level)
1900 #ifdef DEBUGGING_MSTATS
1902 register union overhead *p;
1903 struct chunk_chain_s* nextchain;
1905 buf->topbucket = buf->topbucket_ev = buf->topbucket_odd
1906 = buf->totfree = buf->total = buf->total_chain = 0;
1908 buf->minbucket = MIN_BUCKET;
1910 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
1911 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
1915 buf->ntotal[i] = nmalloc[i];
1917 buf->totfree += j * BUCKET_SIZE_REAL(i);
1918 buf->total += nmalloc[i] * BUCKET_SIZE_REAL(i);
1920 i % 2 ? (buf->topbucket_odd = i) : (buf->topbucket_ev = i);
1924 nextchain = chunk_chain;
1926 buf->total_chain += nextchain->size;
1927 nextchain = nextchain->next;
1929 buf->total_sbrk = goodsbrk + sbrk_slack;
1931 buf->sbrk_good = sbrk_good;
1932 buf->sbrk_slack = sbrk_slack;
1933 buf->start_slack = start_slack;
1934 buf->sbrked_remains = sbrked_remains;
1936 buf->nbuckets = NBUCKETS;
1938 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
1941 buf->bucket_mem_size[i] = BUCKET_SIZE(i);
1942 buf->bucket_available_size[i] = BUCKET_SIZE_REAL(i);
1945 #endif /* defined DEBUGGING_MSTATS */
1946 return 0; /* XXX unused */
1949 * mstats - print out statistics about malloc
1951 * Prints two lines of numbers, one showing the length of the free list
1952 * for each size category, the second showing the number of mallocs -
1953 * frees for each size category.
1956 Perl_dump_mstats(pTHX_ char *s)
1958 #ifdef DEBUGGING_MSTATS
1960 perl_mstats_t buffer;
1966 get_mstats(&buffer, NBUCKETS, 0);
1969 PerlIO_printf(Perl_error_log,
1970 "Memory allocation statistics %s (buckets %"IVdf"(%"IVdf")..%"IVdf"(%"IVdf")\n",
1972 (IV)BUCKET_SIZE_REAL(MIN_BUCKET),
1973 (IV)BUCKET_SIZE(MIN_BUCKET),
1974 (IV)BUCKET_SIZE_REAL(buffer.topbucket),
1975 (IV)BUCKET_SIZE(buffer.topbucket));
1976 PerlIO_printf(Perl_error_log, "%8"IVdf" free:", buffer.totfree);
1977 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
1978 PerlIO_printf(Perl_error_log,
1979 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
1981 : ((i < 12*BUCKETS_PER_POW2) ? " %3"UVuf : " %"UVuf)),
1984 #ifdef BUCKETS_ROOT2
1985 PerlIO_printf(Perl_error_log, "\n\t ");
1986 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
1987 PerlIO_printf(Perl_error_log,
1988 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
1990 : ((i < 12*BUCKETS_PER_POW2) ? " %3"UVuf : " %"UVuf)),
1994 PerlIO_printf(Perl_error_log, "\n%8"IVdf" used:", buffer.total - buffer.totfree);
1995 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
1996 PerlIO_printf(Perl_error_log,
1997 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
1999 : ((i < 12*BUCKETS_PER_POW2) ? " %3"IVdf : " %"IVdf)),
2000 buffer.ntotal[i] - buffer.nfree[i]);
2002 #ifdef BUCKETS_ROOT2
2003 PerlIO_printf(Perl_error_log, "\n\t ");
2004 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
2005 PerlIO_printf(Perl_error_log,
2006 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2008 : ((i < 12*BUCKETS_PER_POW2) ? " %3"IVdf : " %"IVdf)),
2009 buffer.ntotal[i] - buffer.nfree[i]);
2012 PerlIO_printf(Perl_error_log, "\nTotal sbrk(): %"IVdf"/%"IVdf":%"IVdf". Odd ends: pad+heads+chain+tail: %"IVdf"+%"IVdf"+%"IVdf"+%"IVdf".\n",
2013 buffer.total_sbrk, buffer.sbrks, buffer.sbrk_good,
2014 buffer.sbrk_slack, buffer.start_slack,
2015 buffer.total_chain, buffer.sbrked_remains);
2016 #endif /* DEBUGGING_MSTATS */
2020 #ifdef USE_PERL_SBRK
2022 # if defined(__MACHTEN_PPC__) || defined(NeXT) || defined(__NeXT__) || defined(PURIFY)
2023 # define PERL_SBRK_VIA_MALLOC
2026 # ifdef PERL_SBRK_VIA_MALLOC
2028 /* it may seem schizophrenic to use perl's malloc and let it call system */
2029 /* malloc, the reason for that is only the 3.2 version of the OS that had */
2030 /* frequent core dumps within nxzonefreenolock. This sbrk routine put an */
2031 /* end to the cores */
2033 # ifndef SYSTEM_ALLOC
2034 # define SYSTEM_ALLOC(a) malloc(a)
2036 # ifndef SYSTEM_ALLOC_ALIGNMENT
2037 # define SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES
2040 # endif /* PERL_SBRK_VIA_MALLOC */
2042 static IV Perl_sbrk_oldchunk;
2043 static long Perl_sbrk_oldsize;
2045 # define PERLSBRK_32_K (1<<15)
2046 # define PERLSBRK_64_K (1<<16)
2054 if (!size) return 0;
2056 reqsize = size; /* just for the DEBUG_m statement */
2059 size = (size + 0x7ff) & ~0x7ff;
2061 if (size <= Perl_sbrk_oldsize) {
2062 got = Perl_sbrk_oldchunk;
2063 Perl_sbrk_oldchunk += size;
2064 Perl_sbrk_oldsize -= size;
2066 if (size >= PERLSBRK_32_K) {
2069 size = PERLSBRK_64_K;
2072 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2073 size += NEEDED_ALIGNMENT - SYSTEM_ALLOC_ALIGNMENT;
2075 got = (IV)SYSTEM_ALLOC(size);
2076 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2077 got = (got + NEEDED_ALIGNMENT - 1) & ~(NEEDED_ALIGNMENT - 1);
2080 /* Chunk is small, register the rest for future allocs. */
2081 Perl_sbrk_oldchunk = got + reqsize;
2082 Perl_sbrk_oldsize = size - reqsize;
2086 DEBUG_m(PerlIO_printf(Perl_debug_log, "sbrk malloc size %ld (reqsize %ld), left size %ld, give addr 0x%"UVxf"\n",
2087 size, reqsize, Perl_sbrk_oldsize, PTR2UV(got)));
2092 #endif /* ! defined USE_PERL_SBRK */