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"
259 # define Malloc_t void *
265 # define MEM_SIZE unsigned long
268 # define LONG_MAX 0x7FFFFFFF
271 # define UV unsigned long
274 # define caddr_t char *
279 # define Copy(s,d,n,t) (void)memcpy((char*)(d),(char*)(s), (n) * sizeof(t))
280 # define PerlEnv_getenv getenv
281 # define PerlIO_printf fprintf
282 # define PerlIO_stderr() stderr
284 # ifndef croak /* make depend */
285 # define croak(mess, arg) (warn((mess), (arg)), exit(1))
287 # ifndef croak2 /* make depend */
288 # define croak2(mess, arg1, arg2) (warn2((mess), (arg1), (arg2)), exit(1))
291 # define warn(mess, arg) fprintf(stderr, (mess), (arg))
294 # define warn2(mess, arg1) fprintf(stderr, (mess), (arg1), (arg2))
307 # define dTHX extern int Perl___notused PERL_UNUSED_DECL
309 # define dTHX extern int Perl___notused
311 # define WITH_THX(s) s
313 # ifndef PERL_GET_INTERP
314 # define PERL_GET_INTERP PL_curinterp
317 # define Perl_malloc malloc
320 # define Perl_mfree free
322 # ifndef Perl_realloc
323 # define Perl_realloc realloc
326 # define Perl_calloc calloc
329 # define Perl_strdup strdup
334 # define MUTEX_LOCK(l)
338 # define MUTEX_UNLOCK(l)
342 # define MALLOC_LOCK MUTEX_LOCK(&PL_malloc_mutex)
345 #ifndef MALLOC_UNLOCK
346 # define MALLOC_UNLOCK MUTEX_UNLOCK(&PL_malloc_mutex)
349 # ifndef fatalcroak /* make depend */
350 # define fatalcroak(mess) (write(2, (mess), strlen(mess)), exit(2))
355 # define DEBUG_m(a) \
357 if (PERL_GET_INTERP) { dTHX; if (DEBUG_m_TEST) { a; } } \
361 #ifdef PERL_IMPLICIT_CONTEXT
362 # define PERL_IS_ALIVE aTHX
364 # define PERL_IS_ALIVE TRUE
371 * The memory is broken into "blocks" which occupy multiples of 2K (and
372 * generally speaking, have size "close" to a power of 2). The addresses
373 * of such *unused* blocks are kept in nextf[i] with big enough i. (nextf
374 * is an array of linked lists.) (Addresses of used blocks are not known.)
376 * Moreover, since the algorithm may try to "bite" smaller blocks out
377 * of unused bigger ones, there are also regions of "irregular" size,
378 * managed separately, by a linked list chunk_chain.
380 * The third type of storage is the sbrk()ed-but-not-yet-used space, its
381 * end and size are kept in last_sbrk_top and sbrked_remains.
383 * Growing blocks "in place":
384 * ~~~~~~~~~~~~~~~~~~~~~~~~~
385 * The address of the block with the greatest address is kept in last_op
386 * (if not known, last_op is 0). If it is known that the memory above
387 * last_op is not continuous, or contains a chunk from chunk_chain,
388 * last_op is set to 0.
390 * The chunk with address last_op may be grown by expanding into
391 * sbrk()ed-but-not-yet-used space, or trying to sbrk() more continuous
394 * Management of last_op:
395 * ~~~~~~~~~~~~~~~~~~~~~
397 * free() never changes the boundaries of blocks, so is not relevant.
399 * The only way realloc() may change the boundaries of blocks is if it
400 * grows a block "in place". However, in the case of success such a
401 * chunk is automatically last_op, and it remains last_op. In the case
402 * of failure getpages_adjacent() clears last_op.
404 * malloc() may change blocks by calling morecore() only.
406 * morecore() may create new blocks by:
407 * a) biting pieces from chunk_chain (cannot create one above last_op);
408 * b) biting a piece from an unused block (if block was last_op, this
409 * may create a chunk from chain above last_op, thus last_op is
410 * invalidated in such a case).
411 * c) biting of sbrk()ed-but-not-yet-used space. This creates
412 * a block which is last_op.
413 * d) Allocating new pages by calling getpages();
415 * getpages() creates a new block. It marks last_op at the bottom of
416 * the chunk of memory it returns.
418 * Active pages footprint:
419 * ~~~~~~~~~~~~~~~~~~~~~~
420 * Note that we do not need to traverse the lists in nextf[i], just take
421 * the first element of this list. However, we *need* to traverse the
422 * list in chunk_chain, but most the time it should be a very short one,
423 * so we do not step on a lot of pages we are not going to use.
427 * get_from_bigger_buckets(): forget to increment price => Quite
431 /* I don't much care whether these are defined in sys/types.h--LAW */
433 #define u_char unsigned char
434 #define u_int unsigned int
436 * I removed the definition of u_bigint which appeared to be u_bigint = UV
437 * u_bigint was only used in TWOK_MASKED and TWOK_SHIFT
438 * where I have used PTR2UV. RMB
440 #define u_short unsigned short
442 /* 286 and atarist like big chunks, which gives too much overhead. */
443 #if (defined(RCHECK) || defined(I286) || defined(atarist) || defined(__MINT__)) && defined(PACK_MALLOC)
448 * The description below is applicable if PACK_MALLOC is not defined.
450 * The overhead on a block is at least 4 bytes. When free, this space
451 * contains a pointer to the next free block, and the bottom two bits must
452 * be zero. When in use, the first byte is set to MAGIC, and the second
453 * byte is the size index. The remaining bytes are for alignment.
454 * If range checking is enabled and the size of the block fits
455 * in two bytes, then the top two bytes hold the size of the requested block
456 * plus the range checking words, and the header word MINUS ONE.
459 union overhead *ov_next; /* when free */
460 #if MEM_ALIGNBYTES > 4
461 double strut; /* alignment problems */
465 * Keep the ovu_index and ovu_magic in this order, having a char
466 * field first gives alignment indigestion in some systems, such as
469 u_char ovu_index; /* bucket # */
470 u_char ovu_magic; /* magic number */
472 u_short ovu_size; /* actual block size */
473 u_int ovu_rmagic; /* range magic number */
476 #define ov_magic ovu.ovu_magic
477 #define ov_index ovu.ovu_index
478 #define ov_size ovu.ovu_size
479 #define ov_rmagic ovu.ovu_rmagic
482 #define MAGIC 0xff /* magic # on accounting info */
483 #define RMAGIC 0x55555555 /* magic # on range info */
484 #define RMAGIC_C 0x55 /* magic # on range info */
487 # define RSLOP sizeof (u_int)
488 # ifdef TWO_POT_OPTIMIZE
489 # define MAX_SHORT_BUCKET (12 * BUCKETS_PER_POW2)
491 # define MAX_SHORT_BUCKET (13 * BUCKETS_PER_POW2)
497 #if !defined(PACK_MALLOC) && defined(BUCKETS_ROOT2)
498 # undef BUCKETS_ROOT2
502 # define BUCKET_TABLE_SHIFT 2
503 # define BUCKET_POW2_SHIFT 1
504 # define BUCKETS_PER_POW2 2
506 # define BUCKET_TABLE_SHIFT MIN_BUC_POW2
507 # define BUCKET_POW2_SHIFT 0
508 # define BUCKETS_PER_POW2 1
511 #if !defined(MEM_ALIGNBYTES) || ((MEM_ALIGNBYTES > 4) && !defined(STRICT_ALIGNMENT))
512 /* Figure out the alignment of void*. */
517 # define ALIGN_SMALL ((int)((caddr_t)&(((struct aligner*)0)->p)))
519 # define ALIGN_SMALL MEM_ALIGNBYTES
522 #define IF_ALIGN_8(yes,no) ((ALIGN_SMALL>4) ? (yes) : (no))
525 # define MAX_BUCKET_BY_TABLE 13
526 static u_short buck_size[MAX_BUCKET_BY_TABLE + 1] =
528 0, 0, 0, 0, 4, 4, 8, 12, 16, 24, 32, 48, 64, 80,
530 # define BUCKET_SIZE(i) ((i) % 2 ? buck_size[i] : (1 << ((i) >> BUCKET_POW2_SHIFT)))
531 # define BUCKET_SIZE_REAL(i) ((i) <= MAX_BUCKET_BY_TABLE \
533 : ((1 << ((i) >> BUCKET_POW2_SHIFT)) \
535 + POW2_OPTIMIZE_SURPLUS(i)))
537 # define BUCKET_SIZE(i) (1 << ((i) >> BUCKET_POW2_SHIFT))
538 # define BUCKET_SIZE_REAL(i) (BUCKET_SIZE(i) - MEM_OVERHEAD(i) + POW2_OPTIMIZE_SURPLUS(i))
543 /* In this case there are several possible layout of arenas depending
544 * on the size. Arenas are of sizes multiple to 2K, 2K-aligned, and
545 * have a size close to a power of 2.
547 * Arenas of the size >= 4K keep one chunk only. Arenas of size 2K
548 * may keep one chunk or multiple chunks. Here are the possible
551 * # One chunk only, chunksize 2^k + SOMETHING - ALIGN, k >= 11
553 * INDEX MAGIC1 UNUSED CHUNK1
555 * # Multichunk with sanity checking and chunksize 2^k-ALIGN, k>7
557 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 CHUNK2 CHUNK3 ...
559 * # Multichunk with sanity checking and size 2^k-ALIGN, k=7
561 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 UNUSED CHUNK2 CHUNK3 ...
563 * # Multichunk with sanity checking and size up to 80
565 * INDEX UNUSED MAGIC1 UNUSED MAGIC2 UNUSED ... CHUNK1 CHUNK2 CHUNK3 ...
567 * # No sanity check (usually up to 48=byte-long buckets)
568 * INDEX UNUSED CHUNK1 CHUNK2 ...
570 * Above INDEX and MAGIC are one-byte-long. Sizes of UNUSED are
571 * appropriate to keep algorithms simple and memory aligned. INDEX
572 * encodes the size of the chunk, while MAGICn encodes state (used,
573 * free or non-managed-by-us-so-it-indicates-a-bug) of CHUNKn. MAGIC
574 * is used for sanity checking purposes only. SOMETHING is 0 or 4K
575 * (to make size of big CHUNK accomodate allocations for powers of two
578 * [There is no need to alignment between chunks, since C rules ensure
579 * that structs which need 2^k alignment have sizeof which is
580 * divisible by 2^k. Thus as far as the last chunk is aligned at the
581 * end of the arena, and 2K-alignment does not contradict things,
582 * everything is going to be OK for sizes of chunks 2^n and 2^n +
583 * 2^k. Say, 80-bit buckets will be 16-bit aligned, and as far as we
584 * put allocations for requests in 65..80 range, all is fine.
586 * Note, however, that standard malloc() puts more strict
587 * requirements than the above C rules. Moreover, our algorithms of
588 * realloc() may break this idyll, but we suppose that realloc() does
589 * need not change alignment.]
591 * Is very important to make calculation of the offset of MAGICm as
592 * quick as possible, since it is done on each malloc()/free(). In
593 * fact it is so quick that it has quite little effect on the speed of
594 * doing malloc()/free(). [By default] We forego such calculations
595 * for small chunks, but only to save extra 3% of memory, not because
596 * of speed considerations.
598 * Here is the algorithm [which is the same for all the allocations
599 * schemes above], see OV_MAGIC(block,bucket). Let OFFSETm be the
600 * offset of the CHUNKm from the start of ARENA. Then offset of
601 * MAGICm is (OFFSET1 >> SHIFT) + ADDOFFSET. Here SHIFT and ADDOFFSET
602 * are numbers which depend on the size of the chunks only.
604 * Let as check some sanity conditions. Numbers OFFSETm>>SHIFT are
605 * different for all the chunks in the arena if 2^SHIFT is not greater
606 * than size of the chunks in the arena. MAGIC1 will not overwrite
607 * INDEX provided ADDOFFSET is >0 if OFFSET1 < 2^SHIFT. MAGIClast
608 * will not overwrite CHUNK1 if OFFSET1 > (OFFSETlast >> SHIFT) +
611 * Make SHIFT the maximal possible (there is no point in making it
612 * smaller). Since OFFSETlast is 2K - CHUNKSIZE, above restrictions
613 * give restrictions on OFFSET1 and on ADDOFFSET.
615 * In particular, for chunks of size 2^k with k>=6 we can put
616 * ADDOFFSET to be from 0 to 2^k - 2^(11-k), and have
617 * OFFSET1==chunksize. For chunks of size 80 OFFSET1 of 2K%80=48 is
618 * large enough to have ADDOFFSET between 1 and 16 (similarly for 96,
619 * when ADDOFFSET should be 1). In particular, keeping MAGICs for
620 * these sizes gives no additional size penalty.
622 * However, for chunks of size 2^k with k<=5 this gives OFFSET1 >=
623 * ADDOFSET + 2^(11-k). Keeping ADDOFFSET 0 allows for 2^(11-k)-2^(11-2k)
624 * chunks per arena. This is smaller than 2^(11-k) - 1 which are
625 * needed if no MAGIC is kept. [In fact, having a negative ADDOFFSET
626 * would allow for slightly more buckets per arena for k=2,3.]
628 * Similarly, for chunks of size 3/2*2^k with k<=5 MAGICs would span
629 * the area up to 2^(11-k)+ADDOFFSET. For k=4 this give optimal
630 * ADDOFFSET as -7..0. For k=3 ADDOFFSET can go up to 4 (with tiny
631 * savings for negative ADDOFFSET). For k=5 ADDOFFSET can go -1..16
632 * (with no savings for negative values).
634 * In particular, keeping ADDOFFSET 0 for sizes of chunks up to 2^6
635 * leads to tiny pessimizations in case of sizes 4, 8, 12, 24, and
636 * leads to no contradictions except for size=80 (or 96.)
638 * However, it also makes sense to keep no magic for sizes 48 or less.
639 * This is what we do. In this case one needs ADDOFFSET>=1 also for
640 * chunksizes 12, 24, and 48, unless one gets one less chunk per
643 * The algo of OV_MAGIC(block,bucket) keeps ADDOFFSET 0 until
644 * chunksize of 64, then makes it 1.
646 * This allows for an additional optimization: the above scheme leads
647 * to giant overheads for sizes 128 or more (one whole chunk needs to
648 * be sacrifised to keep INDEX). Instead we use chunks not of size
649 * 2^k, but of size 2^k-ALIGN. If we pack these chunks at the end of
650 * the arena, then the beginnings are still in different 2^k-long
651 * sections of the arena if k>=7 for ALIGN==4, and k>=8 if ALIGN=8.
652 * Thus for k>7 the above algo of calculating the offset of the magic
653 * will still give different answers for different chunks. And to
654 * avoid the overrun of MAGIC1 into INDEX, one needs ADDOFFSET of >=1.
655 * In the case k=7 we just move the first chunk an extra ALIGN
656 * backward inside the ARENA (this is done once per arena lifetime,
657 * thus is not a big overhead). */
658 # define MAX_PACKED_POW2 6
659 # define MAX_PACKED (MAX_PACKED_POW2 * BUCKETS_PER_POW2 + BUCKET_POW2_SHIFT)
660 # define MAX_POW2_ALGO ((1<<(MAX_PACKED_POW2 + 1)) - M_OVERHEAD)
661 # define TWOK_MASK ((1<<LOG_OF_MIN_ARENA) - 1)
662 # define TWOK_MASKED(x) (PTR2UV(x) & ~TWOK_MASK)
663 # define TWOK_SHIFT(x) (PTR2UV(x) & TWOK_MASK)
664 # define OV_INDEXp(block) (INT2PTR(u_char*,TWOK_MASKED(block)))
665 # define OV_INDEX(block) (*OV_INDEXp(block))
666 # define OV_MAGIC(block,bucket) (*(OV_INDEXp(block) + \
667 (TWOK_SHIFT(block)>> \
668 (bucket>>BUCKET_POW2_SHIFT)) + \
669 (bucket >= MIN_NEEDS_SHIFT ? 1 : 0)))
670 /* A bucket can have a shift smaller than it size, we need to
671 shift its magic number so it will not overwrite index: */
672 # ifdef BUCKETS_ROOT2
673 # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2 - 1) /* Shift 80 greater than chunk 64. */
675 # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2) /* Shift 128 greater than chunk 32. */
677 # define CHUNK_SHIFT 0
679 /* Number of active buckets of given ordinal. */
680 #ifdef IGNORE_SMALL_BAD_FREE
681 #define FIRST_BUCKET_WITH_CHECK (6 * BUCKETS_PER_POW2) /* 64 */
682 # define N_BLKS(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \
683 ? ((1<<LOG_OF_MIN_ARENA) - 1)/BUCKET_SIZE(bucket) \
686 # define N_BLKS(bucket) n_blks[bucket]
689 static u_short n_blks[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
691 # if BUCKETS_PER_POW2==1
693 (MIN_BUC_POW2==2 ? 384 : 0),
694 224, 120, 62, 31, 16, 8, 4, 2
697 (MIN_BUC_POW2==2 ? 384 : 0), (MIN_BUC_POW2==2 ? 384 : 0), /* 4, 4 */
698 224, 149, 120, 80, 62, 41, 31, 25, 16, 16, 8, 8, 4, 4, 2, 2
702 /* Shift of the first bucket with the given ordinal inside 2K chunk. */
703 #ifdef IGNORE_SMALL_BAD_FREE
704 # define BLK_SHIFT(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \
705 ? ((1<<LOG_OF_MIN_ARENA) \
706 - BUCKET_SIZE(bucket) * N_BLKS(bucket)) \
709 # define BLK_SHIFT(bucket) blk_shift[bucket]
712 static u_short blk_shift[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
714 # if BUCKETS_PER_POW2==1
716 (MIN_BUC_POW2==2 ? 512 : 0),
717 256, 128, 64, 64, /* 8 to 64 */
718 16*sizeof(union overhead),
719 8*sizeof(union overhead),
720 4*sizeof(union overhead),
721 2*sizeof(union overhead),
724 (MIN_BUC_POW2==2 ? 512 : 0), (MIN_BUC_POW2==2 ? 512 : 0),
725 256, 260, 128, 128, 64, 80, 64, 48, /* 8 to 96 */
726 16*sizeof(union overhead), 16*sizeof(union overhead),
727 8*sizeof(union overhead), 8*sizeof(union overhead),
728 4*sizeof(union overhead), 4*sizeof(union overhead),
729 2*sizeof(union overhead), 2*sizeof(union overhead),
733 # define NEEDED_ALIGNMENT 0x800 /* 2k boundaries */
734 # define WANTED_ALIGNMENT 0x800 /* 2k boundaries */
736 #else /* !PACK_MALLOC */
738 # define OV_MAGIC(block,bucket) (block)->ov_magic
739 # define OV_INDEX(block) (block)->ov_index
740 # define CHUNK_SHIFT 1
741 # define MAX_PACKED -1
742 # define NEEDED_ALIGNMENT MEM_ALIGNBYTES
743 # define WANTED_ALIGNMENT 0x400 /* 1k boundaries */
745 #endif /* !PACK_MALLOC */
747 #define M_OVERHEAD (sizeof(union overhead) + RSLOP)
750 # define MEM_OVERHEAD(bucket) \
751 (bucket <= MAX_PACKED ? 0 : M_OVERHEAD)
752 # ifdef SMALL_BUCKET_VIA_TABLE
753 # define START_SHIFTS_BUCKET ((MAX_PACKED_POW2 + 1) * BUCKETS_PER_POW2)
754 # define START_SHIFT MAX_PACKED_POW2
755 # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */
756 # define SIZE_TABLE_MAX 80
758 # define SIZE_TABLE_MAX 64
760 static char bucket_of[] =
762 # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */
763 /* 0 to 15 in 4-byte increments. */
764 (sizeof(void*) > 4 ? 6 : 5), /* 4/8, 5-th bucket for better reports */
766 IF_ALIGN_8(8,7), 8, /* 16/12, 16 */
767 9, 9, 10, 10, /* 24, 32 */
768 11, 11, 11, 11, /* 48 */
769 12, 12, 12, 12, /* 64 */
770 13, 13, 13, 13, /* 80 */
771 13, 13, 13, 13 /* 80 */
772 # else /* !BUCKETS_ROOT2 */
773 /* 0 to 15 in 4-byte increments. */
774 (sizeof(void*) > 4 ? 3 : 2),
780 # endif /* !BUCKETS_ROOT2 */
782 # else /* !SMALL_BUCKET_VIA_TABLE */
783 # define START_SHIFTS_BUCKET MIN_BUCKET
784 # define START_SHIFT (MIN_BUC_POW2 - 1)
785 # endif /* !SMALL_BUCKET_VIA_TABLE */
786 #else /* !PACK_MALLOC */
787 # define MEM_OVERHEAD(bucket) M_OVERHEAD
788 # ifdef SMALL_BUCKET_VIA_TABLE
789 # undef SMALL_BUCKET_VIA_TABLE
791 # define START_SHIFTS_BUCKET MIN_BUCKET
792 # define START_SHIFT (MIN_BUC_POW2 - 1)
793 #endif /* !PACK_MALLOC */
796 * Big allocations are often of the size 2^n bytes. To make them a
797 * little bit better, make blocks of size 2^n+pagesize for big n.
800 #ifdef TWO_POT_OPTIMIZE
802 # ifndef PERL_PAGESIZE
803 # define PERL_PAGESIZE 4096
805 # ifndef FIRST_BIG_POW2
806 # define FIRST_BIG_POW2 15 /* 32K, 16K is used too often. */
808 # define FIRST_BIG_BLOCK (1<<FIRST_BIG_POW2)
809 /* If this value or more, check against bigger blocks. */
810 # define FIRST_BIG_BOUND (FIRST_BIG_BLOCK - M_OVERHEAD)
811 /* If less than this value, goes into 2^n-overhead-block. */
812 # define LAST_SMALL_BOUND ((FIRST_BIG_BLOCK>>1) - M_OVERHEAD)
814 # define POW2_OPTIMIZE_ADJUST(nbytes) \
815 ((nbytes >= FIRST_BIG_BOUND) ? nbytes -= PERL_PAGESIZE : 0)
816 # define POW2_OPTIMIZE_SURPLUS(bucket) \
817 ((bucket >= FIRST_BIG_POW2 * BUCKETS_PER_POW2) ? PERL_PAGESIZE : 0)
819 #else /* !TWO_POT_OPTIMIZE */
820 # define POW2_OPTIMIZE_ADJUST(nbytes)
821 # define POW2_OPTIMIZE_SURPLUS(bucket) 0
822 #endif /* !TWO_POT_OPTIMIZE */
824 #if defined(HAS_64K_LIMIT) && defined(PERL_CORE)
825 # define BARK_64K_LIMIT(what,nbytes,size) \
826 if (nbytes > 0xffff) { \
827 PerlIO_printf(PerlIO_stderr(), \
828 "%s too large: %lx\n", what, size); \
831 #else /* !HAS_64K_LIMIT || !PERL_CORE */
832 # define BARK_64K_LIMIT(what,nbytes,size)
833 #endif /* !HAS_64K_LIMIT || !PERL_CORE */
836 # define MIN_SBRK 2048
840 # define FIRST_SBRK (48*1024)
843 /* Minimal sbrk in percents of what is already alloced. */
844 #ifndef MIN_SBRK_FRAC
845 # define MIN_SBRK_FRAC 3
848 #ifndef SBRK_ALLOW_FAILURES
849 # define SBRK_ALLOW_FAILURES 3
852 #ifndef SBRK_FAILURE_PRICE
853 # define SBRK_FAILURE_PRICE 50
856 static void morecore (register int bucket);
857 # if defined(DEBUGGING)
858 static void botch (char *diag, char *s);
860 static void add_to_chain (void *p, MEM_SIZE size, MEM_SIZE chip);
861 static void* get_from_chain (MEM_SIZE size);
862 static void* get_from_bigger_buckets(int bucket, MEM_SIZE size);
863 static union overhead *getpages (MEM_SIZE needed, int *nblksp, int bucket);
864 static int getpages_adjacent(MEM_SIZE require);
868 #ifdef I_MACH_CTHREADS
870 # define MUTEX_LOCK(m) STMT_START { if (*m) mutex_lock(*m); } STMT_END
872 # define MUTEX_UNLOCK(m) STMT_START { if (*m) mutex_unlock(*m); } STMT_END
876 # define BITS_IN_PTR (8*PTRSIZE)
880 * nextf[i] is the pointer to the next free block of size 2^i. The
881 * smallest allocatable block is 8 bytes. The overhead information
882 * precedes the data area returned to the user.
884 #define NBUCKETS (BITS_IN_PTR*BUCKETS_PER_POW2 + 1)
885 static union overhead *nextf[NBUCKETS];
887 #if defined(PURIFY) && !defined(USE_PERL_SBRK)
888 # define USE_PERL_SBRK
892 # define sbrk(a) Perl_sbrk(a)
893 Malloc_t Perl_sbrk (int size);
895 # ifndef HAS_SBRK_PROTO /* <unistd.h> usually takes care of this */
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 # ifdef PERL_EMERGENCY_SBRK
917 # define BIG_SIZE (1<<16) /* 64K */
920 static char *emergency_buffer;
921 static MEM_SIZE emergency_buffer_size;
922 static int no_mem; /* 0 if the last request for more memory succeeded.
923 Otherwise the size of the failing request. */
926 emergency_sbrk(MEM_SIZE size)
928 MEM_SIZE rsize = (((size - 1)>>LOG_OF_MIN_ARENA) + 1)<<LOG_OF_MIN_ARENA;
930 if (size >= BIG_SIZE && (!no_mem || (size < no_mem))) {
931 /* Give the possibility to recover, but avoid an infinite cycle. */
934 croak2("Out of memory during \"large\" request for %"UVuf" bytes, total sbrk() is %"UVuf" bytes", (UV)size, (UV)(goodsbrk + sbrk_slack));
937 if (emergency_buffer_size >= rsize) {
938 char *old = emergency_buffer;
940 emergency_buffer_size -= rsize;
941 emergency_buffer += rsize;
945 /* First offense, give a possibility to recover by dieing. */
946 /* No malloc involved here: */
947 GV **gvp = (GV**)hv_fetch(PL_defstash, "^M", 2, 0);
953 if (emergency_buffer_size) {
954 add_to_chain(emergency_buffer, emergency_buffer_size, 0);
955 emergency_buffer_size = 0;
956 emergency_buffer = Nullch;
959 if (!gvp) gvp = (GV**)hv_fetch(PL_defstash, "\015", 1, 0);
960 if (!gvp || !(sv = GvSV(*gvp)) || !SvPOK(sv)
961 || (SvLEN(sv) < (1<<LOG_OF_MIN_ARENA) - M_OVERHEAD)) {
964 return (char *)-1; /* Now die die die... */
966 /* Got it, now detach SvPV: */
968 /* Check alignment: */
969 if ((PTR2UV(pv) - sizeof(union overhead)) & (NEEDED_ALIGNMENT - 1)) {
970 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
971 return (char *)-1; /* die die die */
974 emergency_buffer = pv - sizeof(union overhead);
975 emergency_buffer_size = malloced_size(pv) + M_OVERHEAD;
978 SvCUR(sv) = SvLEN(sv) = 0;
982 croak("Out of memory during request for %"UVuf" bytes, total sbrk() is %"UVuf" bytes", (UV)size, (UV)(goodsbrk + sbrk_slack));
987 # else /* !defined(PERL_EMERGENCY_SBRK) */
988 # define emergency_sbrk(size) -1
990 #endif /* ifdef PERL_CORE */
994 #define ASSERT(p,diag) if (!(p)) botch(diag,STRINGIFY(p)); else
996 botch(char *diag, char *s)
999 PerlIO_printf(PerlIO_stderr(), "assertion botched (%s?): %s\n", diag, s);
1003 #define ASSERT(p, diag)
1007 Perl_malloc(register size_t nbytes)
1009 register union overhead *p;
1010 register int bucket;
1011 register MEM_SIZE shiftr;
1013 #if defined(DEBUGGING) || defined(RCHECK)
1014 MEM_SIZE size = nbytes;
1017 BARK_64K_LIMIT("Allocation",nbytes,nbytes);
1019 if ((long)nbytes < 0)
1020 croak("%s", "panic: malloc");
1024 * Convert amount of memory requested into
1025 * closest block size stored in hash buckets
1026 * which satisfies request. Account for
1027 * space used per block for accounting.
1030 # ifdef SMALL_BUCKET_VIA_TABLE
1032 bucket = MIN_BUCKET;
1033 else if (nbytes <= SIZE_TABLE_MAX) {
1034 bucket = bucket_of[(nbytes - 1) >> BUCKET_TABLE_SHIFT];
1039 if (nbytes <= MAX_POW2_ALGO) goto do_shifts;
1044 POW2_OPTIMIZE_ADJUST(nbytes);
1045 nbytes += M_OVERHEAD;
1046 nbytes = (nbytes + 3) &~ 3;
1047 #if defined(PACK_MALLOC) && !defined(SMALL_BUCKET_VIA_TABLE)
1050 shiftr = (nbytes - 1) >> START_SHIFT;
1051 bucket = START_SHIFTS_BUCKET;
1052 /* apart from this loop, this is O(1) */
1053 while (shiftr >>= 1)
1054 bucket += BUCKETS_PER_POW2;
1058 * If nothing in hash bucket right now,
1059 * request more memory from the system.
1061 if (nextf[bucket] == NULL)
1063 if ((p = nextf[bucket]) == NULL) {
1069 #if defined(PLAIN_MALLOC) && defined(NO_FANCY_MALLOC)
1070 PerlIO_puts(PerlIO_stderr(),"Out of memory!\n");
1073 char *eb = buff + sizeof(buff) - 1;
1077 PerlIO_puts(PerlIO_stderr(),"Out of memory during request for ");
1078 #if defined(DEBUGGING) || defined(RCHECK)
1083 *--s = '0' + (n % 10);
1085 PerlIO_puts(PerlIO_stderr(),s);
1086 PerlIO_puts(PerlIO_stderr()," bytes, total sbrk() is ");
1088 n = goodsbrk + sbrk_slack;
1090 *--s = '0' + (n % 10);
1092 PerlIO_puts(PerlIO_stderr(),s);
1093 PerlIO_puts(PerlIO_stderr()," bytes!\n");
1094 #endif /* defined(PLAIN_MALLOC) && defined(NO_FANCY_MALLOC) */
1102 DEBUG_m(PerlIO_printf(Perl_debug_log,
1103 "0x%"UVxf": (%05lu) malloc %ld bytes\n",
1104 PTR2UV(p), (unsigned long)(PL_an++),
1107 /* remove from linked list */
1109 if ((PTR2UV(p)) & (MEM_ALIGNBYTES - 1)) {
1111 PerlIO_printf(PerlIO_stderr(),
1112 "Unaligned pointer in the free chain 0x%"UVxf"\n",
1115 if ((PTR2UV(p->ov_next)) & (MEM_ALIGNBYTES - 1)) {
1117 PerlIO_printf(PerlIO_stderr(),
1118 "Unaligned `next' pointer in the free "
1119 "chain 0x%"UVxf" at 0x%"UVxf"\n",
1120 PTR2UV(p->ov_next), PTR2UV(p));
1123 nextf[bucket] = p->ov_next;
1127 #ifdef IGNORE_SMALL_BAD_FREE
1128 if (bucket >= FIRST_BUCKET_WITH_CHECK)
1130 OV_MAGIC(p, bucket) = MAGIC;
1132 OV_INDEX(p) = bucket;
1136 * Record allocated size of block and
1137 * bound space with magic numbers.
1139 p->ov_rmagic = RMAGIC;
1140 if (bucket <= MAX_SHORT_BUCKET) {
1143 nbytes = size + M_OVERHEAD;
1144 p->ov_size = nbytes - 1;
1145 if ((i = nbytes & 3)) {
1148 *((char *)((caddr_t)p + nbytes - RSLOP + i)) = RMAGIC_C;
1150 nbytes = (nbytes + 3) &~ 3;
1151 *((u_int *)((caddr_t)p + nbytes - RSLOP)) = RMAGIC;
1154 return ((Malloc_t)(p + CHUNK_SHIFT));
1157 static char *last_sbrk_top;
1158 static char *last_op; /* This arena can be easily extended. */
1159 static int sbrked_remains;
1160 static int sbrk_good = SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE;
1162 #ifdef DEBUGGING_MSTATS
1166 struct chunk_chain_s {
1167 struct chunk_chain_s *next;
1170 static struct chunk_chain_s *chunk_chain;
1171 static int n_chunks;
1172 static char max_bucket;
1174 /* Cutoff a piece of one of the chunks in the chain. Prefer smaller chunk. */
1176 get_from_chain(MEM_SIZE size)
1178 struct chunk_chain_s *elt = chunk_chain, **oldp = &chunk_chain;
1179 struct chunk_chain_s **oldgoodp = NULL;
1180 long min_remain = LONG_MAX;
1183 if (elt->size >= size) {
1184 long remains = elt->size - size;
1185 if (remains >= 0 && remains < min_remain) {
1187 min_remain = remains;
1193 oldp = &( elt->next );
1196 if (!oldgoodp) return NULL;
1198 void *ret = *oldgoodp;
1199 struct chunk_chain_s *next = (*oldgoodp)->next;
1201 *oldgoodp = (struct chunk_chain_s *)((char*)ret + size);
1202 (*oldgoodp)->size = min_remain;
1203 (*oldgoodp)->next = next;
1206 void *ret = *oldgoodp;
1207 *oldgoodp = (*oldgoodp)->next;
1214 add_to_chain(void *p, MEM_SIZE size, MEM_SIZE chip)
1216 struct chunk_chain_s *next = chunk_chain;
1217 char *cp = (char*)p;
1220 chunk_chain = (struct chunk_chain_s *)cp;
1221 chunk_chain->size = size - chip;
1222 chunk_chain->next = next;
1227 get_from_bigger_buckets(int bucket, MEM_SIZE size)
1230 static int bucketprice[NBUCKETS];
1231 while (bucket <= max_bucket) {
1232 /* We postpone stealing from bigger buckets until we want it
1234 if (nextf[bucket] && bucketprice[bucket]++ >= price) {
1236 void *ret = (void*)(nextf[bucket] - 1 + CHUNK_SHIFT);
1237 bucketprice[bucket] = 0;
1238 if (((char*)nextf[bucket]) - M_OVERHEAD == last_op) {
1239 last_op = NULL; /* Disable optimization */
1241 nextf[bucket] = nextf[bucket]->ov_next;
1242 #ifdef DEBUGGING_MSTATS
1244 start_slack -= M_OVERHEAD;
1246 add_to_chain(ret, (BUCKET_SIZE(bucket) +
1247 POW2_OPTIMIZE_SURPLUS(bucket)),
1256 static union overhead *
1257 getpages(MEM_SIZE needed, int *nblksp, int bucket)
1259 /* Need to do (possibly expensive) system call. Try to
1260 optimize it for rare calling. */
1261 MEM_SIZE require = needed - sbrked_remains;
1263 union overhead *ovp;
1266 if (sbrk_good > 0) {
1267 if (!last_sbrk_top && require < FIRST_SBRK)
1268 require = FIRST_SBRK;
1269 else if (require < MIN_SBRK) require = MIN_SBRK;
1271 if (require < goodsbrk * MIN_SBRK_FRAC / 100)
1272 require = goodsbrk * MIN_SBRK_FRAC / 100;
1273 require = ((require - 1 + MIN_SBRK) / MIN_SBRK) * MIN_SBRK;
1280 DEBUG_m(PerlIO_printf(Perl_debug_log,
1281 "sbrk(%ld) for %ld-byte-long arena\n",
1282 (long)require, (long) needed));
1283 cp = (char *)sbrk(require);
1284 #ifdef DEBUGGING_MSTATS
1287 if (cp == last_sbrk_top) {
1288 /* Common case, anything is fine. */
1290 ovp = (union overhead *) (cp - sbrked_remains);
1291 last_op = cp - sbrked_remains;
1292 sbrked_remains = require - (needed - sbrked_remains);
1293 } else if (cp == (char *)-1) { /* no more room! */
1294 ovp = (union overhead *)emergency_sbrk(needed);
1295 if (ovp == (union overhead *)-1)
1297 if (((char*)ovp) > last_op) { /* Cannot happen with current emergency_sbrk() */
1301 } else { /* Non-continuous or first sbrk(). */
1302 long add = sbrked_remains;
1305 if (sbrked_remains) { /* Put rest into chain, we
1306 cannot use it right now. */
1307 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1311 /* Second, check alignment. */
1314 #if !defined(atarist) && !defined(__MINT__) /* on the atari we dont have to worry about this */
1315 # ifndef I286 /* The sbrk(0) call on the I286 always returns the next segment */
1316 /* WANTED_ALIGNMENT may be more than NEEDED_ALIGNMENT, but this may
1317 improve performance of memory access. */
1318 if (PTR2UV(cp) & (WANTED_ALIGNMENT - 1)) { /* Not aligned. */
1319 slack = WANTED_ALIGNMENT - (PTR2UV(cp) & (WANTED_ALIGNMENT - 1));
1323 #endif /* !atarist && !MINT */
1326 DEBUG_m(PerlIO_printf(Perl_debug_log,
1327 "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",
1328 (long)add, (long) slack,
1329 (long) sbrked_remains));
1330 newcp = (char *)sbrk(add);
1331 #if defined(DEBUGGING_MSTATS)
1335 if (newcp != cp + require) {
1336 /* Too bad: even rounding sbrk() is not continuous.*/
1337 DEBUG_m(PerlIO_printf(Perl_debug_log,
1338 "failed to fix bad sbrk()\n"));
1342 fatalcroak("panic: Off-page sbrk\n");
1345 if (sbrked_remains) {
1347 #if defined(DEBUGGING_MSTATS)
1348 sbrk_slack += require;
1351 DEBUG_m(PerlIO_printf(Perl_debug_log,
1352 "straight sbrk(%ld)\n",
1354 cp = (char *)sbrk(require);
1355 #ifdef DEBUGGING_MSTATS
1358 if (cp == (char *)-1)
1361 sbrk_good = -1; /* Disable optimization!
1362 Continue with not-aligned... */
1365 require += sbrked_remains;
1369 if (last_sbrk_top) {
1370 sbrk_good -= SBRK_FAILURE_PRICE;
1373 ovp = (union overhead *) cp;
1375 * Round up to minimum allocation size boundary
1376 * and deduct from block count to reflect.
1379 # if NEEDED_ALIGNMENT > MEM_ALIGNBYTES
1380 if (PTR2UV(ovp) & (NEEDED_ALIGNMENT - 1))
1381 fatalcroak("Misalignment of sbrk()\n");
1384 #ifndef I286 /* Again, this should always be ok on an 80286 */
1385 if (PTR2UV(ovp) & (MEM_ALIGNBYTES - 1)) {
1386 DEBUG_m(PerlIO_printf(Perl_debug_log,
1387 "fixing sbrk(): %d bytes off machine alignement\n",
1388 (int)(PTR2UV(ovp) & (MEM_ALIGNBYTES - 1))));
1389 ovp = INT2PTR(union overhead *,(PTR2UV(ovp) + MEM_ALIGNBYTES) &
1390 (MEM_ALIGNBYTES - 1));
1392 # if defined(DEBUGGING_MSTATS)
1393 /* This is only approx. if TWO_POT_OPTIMIZE: */
1394 sbrk_slack += (1 << (bucket >> BUCKET_POW2_SHIFT));
1398 ; /* Finish `else' */
1399 sbrked_remains = require - needed;
1402 #if !defined(PLAIN_MALLOC) && !defined(NO_FANCY_MALLOC)
1405 last_sbrk_top = cp + require;
1406 #ifdef DEBUGGING_MSTATS
1407 goodsbrk += require;
1413 getpages_adjacent(MEM_SIZE require)
1415 if (require <= sbrked_remains) {
1416 sbrked_remains -= require;
1420 require -= sbrked_remains;
1421 /* We do not try to optimize sbrks here, we go for place. */
1422 cp = (char*) sbrk(require);
1423 #ifdef DEBUGGING_MSTATS
1425 goodsbrk += require;
1427 if (cp == last_sbrk_top) {
1429 last_sbrk_top = cp + require;
1431 if (cp == (char*)-1) { /* Out of memory */
1432 #ifdef DEBUGGING_MSTATS
1433 goodsbrk -= require;
1437 /* Report the failure: */
1439 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1441 add_to_chain((void*)cp, require, 0);
1442 sbrk_good -= SBRK_FAILURE_PRICE;
1454 * Allocate more memory to the indicated bucket.
1457 morecore(register int bucket)
1459 register union overhead *ovp;
1460 register int rnu; /* 2^rnu bytes will be requested */
1461 int nblks; /* become nblks blocks of the desired size */
1462 register MEM_SIZE siz, needed;
1466 if (bucket == sizeof(MEM_SIZE)*8*BUCKETS_PER_POW2) {
1468 croak("%s", "Out of memory during ridiculously large request");
1470 if (bucket > max_bucket)
1471 max_bucket = bucket;
1473 rnu = ( (bucket <= (LOG_OF_MIN_ARENA << BUCKET_POW2_SHIFT))
1475 : (bucket >> BUCKET_POW2_SHIFT) );
1476 /* This may be overwritten later: */
1477 nblks = 1 << (rnu - (bucket >> BUCKET_POW2_SHIFT)); /* how many blocks to get */
1478 needed = ((MEM_SIZE)1 << rnu) + POW2_OPTIMIZE_SURPLUS(bucket);
1479 if (nextf[rnu << BUCKET_POW2_SHIFT]) { /* 2048b bucket. */
1480 ovp = nextf[rnu << BUCKET_POW2_SHIFT] - 1 + CHUNK_SHIFT;
1481 nextf[rnu << BUCKET_POW2_SHIFT]
1482 = nextf[rnu << BUCKET_POW2_SHIFT]->ov_next;
1483 #ifdef DEBUGGING_MSTATS
1484 nmalloc[rnu << BUCKET_POW2_SHIFT]--;
1485 start_slack -= M_OVERHEAD;
1487 DEBUG_m(PerlIO_printf(Perl_debug_log,
1488 "stealing %ld bytes from %ld arena\n",
1489 (long) needed, (long) rnu << BUCKET_POW2_SHIFT));
1490 } else if (chunk_chain
1491 && (ovp = (union overhead*) get_from_chain(needed))) {
1492 DEBUG_m(PerlIO_printf(Perl_debug_log,
1493 "stealing %ld bytes from chain\n",
1495 } else if ( (ovp = (union overhead*)
1496 get_from_bigger_buckets((rnu << BUCKET_POW2_SHIFT) + 1,
1498 DEBUG_m(PerlIO_printf(Perl_debug_log,
1499 "stealing %ld bytes from bigger buckets\n",
1501 } else if (needed <= sbrked_remains) {
1502 ovp = (union overhead *)(last_sbrk_top - sbrked_remains);
1503 sbrked_remains -= needed;
1504 last_op = (char*)ovp;
1506 ovp = getpages(needed, &nblks, bucket);
1512 * Add new memory allocated to that on
1513 * free list for this hash bucket.
1515 siz = BUCKET_SIZE(bucket);
1517 *(u_char*)ovp = bucket; /* Fill index. */
1518 if (bucket <= MAX_PACKED) {
1519 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1520 nblks = N_BLKS(bucket);
1521 # ifdef DEBUGGING_MSTATS
1522 start_slack += BLK_SHIFT(bucket);
1524 } else if (bucket < LOG_OF_MIN_ARENA * BUCKETS_PER_POW2) {
1525 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1526 siz -= sizeof(union overhead);
1527 } else ovp++; /* One chunk per block. */
1528 #endif /* PACK_MALLOC */
1529 nextf[bucket] = ovp;
1530 #ifdef DEBUGGING_MSTATS
1531 nmalloc[bucket] += nblks;
1532 if (bucket > MAX_PACKED) {
1533 start_slack += M_OVERHEAD * nblks;
1536 while (--nblks > 0) {
1537 ovp->ov_next = (union overhead *)((caddr_t)ovp + siz);
1538 ovp = (union overhead *)((caddr_t)ovp + siz);
1540 /* Not all sbrks return zeroed memory.*/
1541 ovp->ov_next = (union overhead *)NULL;
1543 if (bucket == 7*BUCKETS_PER_POW2) { /* Special case, explanation is above. */
1544 union overhead *n_op = nextf[7*BUCKETS_PER_POW2]->ov_next;
1545 nextf[7*BUCKETS_PER_POW2] =
1546 (union overhead *)((caddr_t)nextf[7*BUCKETS_PER_POW2]
1547 - sizeof(union overhead));
1548 nextf[7*BUCKETS_PER_POW2]->ov_next = n_op;
1550 #endif /* !PACK_MALLOC */
1554 Perl_mfree(void *mp)
1556 register MEM_SIZE size;
1557 register union overhead *ovp;
1558 char *cp = (char*)mp;
1563 DEBUG_m(PerlIO_printf(Perl_debug_log,
1564 "0x%"UVxf": (%05lu) free\n",
1565 PTR2UV(cp), (unsigned long)(PL_an++)));
1569 ovp = (union overhead *)((caddr_t)cp
1570 - sizeof (union overhead) * CHUNK_SHIFT);
1572 bucket = OV_INDEX(ovp);
1574 #ifdef IGNORE_SMALL_BAD_FREE
1575 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
1576 && (OV_MAGIC(ovp, bucket) != MAGIC))
1578 if (OV_MAGIC(ovp, bucket) != MAGIC)
1581 static int bad_free_warn = -1;
1582 if (bad_free_warn == -1) {
1584 char *pbf = PerlEnv_getenv("PERL_BADFREE");
1585 bad_free_warn = (pbf) ? atoi(pbf) : 1;
1593 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1594 Perl_warner(aTHX_ WARN_MALLOC, "%s free() ignored (RMAGIC, PERL_CORE)",
1595 ovp->ov_rmagic == RMAGIC - 1 ?
1596 "Duplicate" : "Bad");
1599 warn("%s free() ignored (RMAGIC)",
1600 ovp->ov_rmagic == RMAGIC - 1 ? "Duplicate" : "Bad");
1606 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1607 Perl_warner(aTHX_ WARN_MALLOC, "%s", "Bad free() ignored (PERL_CORE)");
1610 warn("%s", "Bad free() ignored");
1613 return; /* sanity */
1616 ASSERT(ovp->ov_rmagic == RMAGIC, "chunk's head overwrite");
1617 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
1619 MEM_SIZE nbytes = ovp->ov_size + 1;
1621 if ((i = nbytes & 3)) {
1624 ASSERT(*((char *)((caddr_t)ovp + nbytes - RSLOP + i))
1625 == RMAGIC_C, "chunk's tail overwrite");
1628 nbytes = (nbytes + 3) &~ 3;
1629 ASSERT(*(u_int *)((caddr_t)ovp + nbytes - RSLOP) == RMAGIC, "chunk's tail overwrite");
1631 ovp->ov_rmagic = RMAGIC - 1;
1633 ASSERT(OV_INDEX(ovp) < NBUCKETS, "chunk's head overwrite");
1634 size = OV_INDEX(ovp);
1637 ovp->ov_next = nextf[size];
1642 /* There is no need to do any locking in realloc (with an exception of
1643 trying to grow in place if we are at the end of the chain).
1644 If somebody calls us from a different thread with the same address,
1645 we are sole anyway. */
1648 Perl_realloc(void *mp, size_t nbytes)
1650 register MEM_SIZE onb;
1651 union overhead *ovp;
1654 register int bucket;
1655 int incr; /* 1 if does not fit, -1 if "easily" fits in a
1656 smaller bucket, otherwise 0. */
1657 char *cp = (char*)mp;
1659 #if defined(DEBUGGING) || !defined(PERL_CORE)
1660 MEM_SIZE size = nbytes;
1662 if ((long)nbytes < 0)
1663 croak("%s", "panic: realloc");
1666 BARK_64K_LIMIT("Reallocation",nbytes,size);
1668 return Perl_malloc(nbytes);
1670 ovp = (union overhead *)((caddr_t)cp
1671 - sizeof (union overhead) * CHUNK_SHIFT);
1672 bucket = OV_INDEX(ovp);
1674 #ifdef IGNORE_SMALL_BAD_FREE
1675 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
1676 && (OV_MAGIC(ovp, bucket) != MAGIC))
1678 if (OV_MAGIC(ovp, bucket) != MAGIC)
1681 static int bad_free_warn = -1;
1682 if (bad_free_warn == -1) {
1684 char *pbf = PerlEnv_getenv("PERL_BADFREE");
1685 bad_free_warn = (pbf) ? atoi(pbf) : 1;
1693 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1694 Perl_warner(aTHX_ WARN_MALLOC, "%srealloc() %signored",
1695 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
1696 ovp->ov_rmagic == RMAGIC - 1
1697 ? "of freed memory " : "");
1700 warn("%srealloc() %signored",
1701 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
1702 ovp->ov_rmagic == RMAGIC - 1 ? "of freed memory " : "");
1708 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1709 Perl_warner(aTHX_ WARN_MALLOC, "%s",
1710 "Bad realloc() ignored");
1713 warn("%s", "Bad realloc() ignored");
1716 return Nullch; /* sanity */
1719 onb = BUCKET_SIZE_REAL(bucket);
1721 * avoid the copy if same size block.
1722 * We are not agressive with boundary cases. Note that it might
1723 * (for a small number of cases) give false negative if
1724 * both new size and old one are in the bucket for
1725 * FIRST_BIG_POW2, but the new one is near the lower end.
1727 * We do not try to go to 1.5 times smaller bucket so far.
1729 if (nbytes > onb) incr = 1;
1731 #ifdef DO_NOT_TRY_HARDER_WHEN_SHRINKING
1732 if ( /* This is a little bit pessimal if PACK_MALLOC: */
1733 nbytes > ( (onb >> 1) - M_OVERHEAD )
1734 # ifdef TWO_POT_OPTIMIZE
1735 || (bucket == FIRST_BIG_POW2 && nbytes >= LAST_SMALL_BOUND )
1738 #else /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
1739 prev_bucket = ( (bucket > MAX_PACKED + 1)
1740 ? bucket - BUCKETS_PER_POW2
1742 if (nbytes > BUCKET_SIZE_REAL(prev_bucket))
1743 #endif /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
1747 #ifdef STRESS_REALLOC
1754 * Record new allocated size of block and
1755 * bound space with magic numbers.
1757 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
1758 int i, nb = ovp->ov_size + 1;
1763 ASSERT(*((char *)((caddr_t)ovp + nb - RSLOP + i)) == RMAGIC_C, "chunk's tail overwrite");
1767 ASSERT(*(u_int *)((caddr_t)ovp + nb - RSLOP) == RMAGIC, "chunk's tail overwrite");
1769 * Convert amount of memory requested into
1770 * closest block size stored in hash buckets
1771 * which satisfies request. Account for
1772 * space used per block for accounting.
1774 nbytes += M_OVERHEAD;
1775 ovp->ov_size = nbytes - 1;
1776 if ((i = nbytes & 3)) {
1779 *((char *)((caddr_t)ovp + nbytes - RSLOP + i))
1782 nbytes = (nbytes + 3) &~ 3;
1783 *((u_int *)((caddr_t)ovp + nbytes - RSLOP)) = RMAGIC;
1787 DEBUG_m(PerlIO_printf(Perl_debug_log,
1788 "0x%"UVxf": (%05lu) realloc %ld bytes inplace\n",
1789 PTR2UV(res),(unsigned long)(PL_an++),
1791 } else if (incr == 1 && (cp - M_OVERHEAD == last_op)
1792 && (onb > (1 << LOG_OF_MIN_ARENA))) {
1793 MEM_SIZE require, newarena = nbytes, pow;
1796 POW2_OPTIMIZE_ADJUST(newarena);
1797 newarena = newarena + M_OVERHEAD;
1798 /* newarena = (newarena + 3) &~ 3; */
1799 shiftr = (newarena - 1) >> LOG_OF_MIN_ARENA;
1800 pow = LOG_OF_MIN_ARENA + 1;
1801 /* apart from this loop, this is O(1) */
1802 while (shiftr >>= 1)
1804 newarena = (1 << pow) + POW2_OPTIMIZE_SURPLUS(pow * BUCKETS_PER_POW2);
1805 require = newarena - onb - M_OVERHEAD;
1808 if (cp - M_OVERHEAD == last_op /* We *still* are the last chunk */
1809 && getpages_adjacent(require)) {
1810 #ifdef DEBUGGING_MSTATS
1812 nmalloc[pow * BUCKETS_PER_POW2]++;
1814 *(cp - M_OVERHEAD) = pow * BUCKETS_PER_POW2; /* Fill index. */
1823 DEBUG_m(PerlIO_printf(Perl_debug_log,
1824 "0x%"UVxf": (%05lu) realloc %ld bytes the hard way\n",
1825 PTR2UV(cp),(unsigned long)(PL_an++),
1827 if ((res = (char*)Perl_malloc(nbytes)) == NULL)
1829 if (cp != res) /* common optimization */
1830 Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char);
1833 return ((Malloc_t)res);
1837 Perl_calloc(register size_t elements, register size_t size)
1839 long sz = elements * size;
1840 Malloc_t p = Perl_malloc(sz);
1843 memset((void*)p, 0, sz);
1849 Perl_strdup(const char *s)
1851 MEM_SIZE l = strlen(s);
1852 char *s1 = (char *)Perl_malloc(l+1);
1854 Copy(s, s1, (MEM_SIZE)(l+1), char);
1860 Perl_putenv(char *a)
1862 /* Sometimes system's putenv conflicts with my_setenv() - this is system
1863 malloc vs Perl's free(). */
1870 while (*val && *val != '=')
1875 if (l < sizeof(buf))
1878 var = Perl_malloc(l + 1);
1879 Copy(a, var, l, char);
1881 my_setenv(var, val+1);
1889 Perl_malloced_size(void *p)
1891 union overhead *ovp = (union overhead *)
1892 ((caddr_t)p - sizeof (union overhead) * CHUNK_SHIFT);
1893 int bucket = OV_INDEX(ovp);
1895 /* The caller wants to have a complete control over the chunk,
1896 disable the memory checking inside the chunk. */
1897 if (bucket <= MAX_SHORT_BUCKET) {
1898 MEM_SIZE size = BUCKET_SIZE_REAL(bucket);
1899 ovp->ov_size = size + M_OVERHEAD - 1;
1900 *((u_int *)((caddr_t)ovp + size + M_OVERHEAD - RSLOP)) = RMAGIC;
1903 return BUCKET_SIZE_REAL(bucket);
1906 # ifdef BUCKETS_ROOT2
1907 # define MIN_EVEN_REPORT 6
1909 # define MIN_EVEN_REPORT MIN_BUCKET
1913 Perl_get_mstats(pTHX_ perl_mstats_t *buf, int buflen, int level)
1915 #ifdef DEBUGGING_MSTATS
1917 register union overhead *p;
1918 struct chunk_chain_s* nextchain;
1920 buf->topbucket = buf->topbucket_ev = buf->topbucket_odd
1921 = buf->totfree = buf->total = buf->total_chain = 0;
1923 buf->minbucket = MIN_BUCKET;
1925 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
1926 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
1930 buf->ntotal[i] = nmalloc[i];
1932 buf->totfree += j * BUCKET_SIZE_REAL(i);
1933 buf->total += nmalloc[i] * BUCKET_SIZE_REAL(i);
1935 i % 2 ? (buf->topbucket_odd = i) : (buf->topbucket_ev = i);
1939 nextchain = chunk_chain;
1941 buf->total_chain += nextchain->size;
1942 nextchain = nextchain->next;
1944 buf->total_sbrk = goodsbrk + sbrk_slack;
1946 buf->sbrk_good = sbrk_good;
1947 buf->sbrk_slack = sbrk_slack;
1948 buf->start_slack = start_slack;
1949 buf->sbrked_remains = sbrked_remains;
1951 buf->nbuckets = NBUCKETS;
1953 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
1956 buf->bucket_mem_size[i] = BUCKET_SIZE(i);
1957 buf->bucket_available_size[i] = BUCKET_SIZE_REAL(i);
1960 #endif /* defined DEBUGGING_MSTATS */
1961 return 0; /* XXX unused */
1964 * mstats - print out statistics about malloc
1966 * Prints two lines of numbers, one showing the length of the free list
1967 * for each size category, the second showing the number of mallocs -
1968 * frees for each size category.
1971 Perl_dump_mstats(pTHX_ char *s)
1973 #ifdef DEBUGGING_MSTATS
1975 perl_mstats_t buffer;
1981 get_mstats(&buffer, NBUCKETS, 0);
1984 PerlIO_printf(Perl_error_log,
1985 "Memory allocation statistics %s (buckets %"IVdf"(%"IVdf")..%"IVdf"(%"IVdf")\n",
1987 (IV)BUCKET_SIZE_REAL(MIN_BUCKET),
1988 (IV)BUCKET_SIZE(MIN_BUCKET),
1989 (IV)BUCKET_SIZE_REAL(buffer.topbucket),
1990 (IV)BUCKET_SIZE(buffer.topbucket));
1991 PerlIO_printf(Perl_error_log, "%8"IVdf" free:", buffer.totfree);
1992 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
1993 PerlIO_printf(Perl_error_log,
1994 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
1996 : ((i < 12*BUCKETS_PER_POW2) ? " %3"UVuf : " %"UVuf)),
1999 #ifdef BUCKETS_ROOT2
2000 PerlIO_printf(Perl_error_log, "\n\t ");
2001 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
2002 PerlIO_printf(Perl_error_log,
2003 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2005 : ((i < 12*BUCKETS_PER_POW2) ? " %3"UVuf : " %"UVuf)),
2009 PerlIO_printf(Perl_error_log, "\n%8"IVdf" used:", buffer.total - buffer.totfree);
2010 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
2011 PerlIO_printf(Perl_error_log,
2012 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2014 : ((i < 12*BUCKETS_PER_POW2) ? " %3"IVdf : " %"IVdf)),
2015 buffer.ntotal[i] - buffer.nfree[i]);
2017 #ifdef BUCKETS_ROOT2
2018 PerlIO_printf(Perl_error_log, "\n\t ");
2019 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
2020 PerlIO_printf(Perl_error_log,
2021 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2023 : ((i < 12*BUCKETS_PER_POW2) ? " %3"IVdf : " %"IVdf)),
2024 buffer.ntotal[i] - buffer.nfree[i]);
2027 PerlIO_printf(Perl_error_log, "\nTotal sbrk(): %"IVdf"/%"IVdf":%"IVdf". Odd ends: pad+heads+chain+tail: %"IVdf"+%"IVdf"+%"IVdf"+%"IVdf".\n",
2028 buffer.total_sbrk, buffer.sbrks, buffer.sbrk_good,
2029 buffer.sbrk_slack, buffer.start_slack,
2030 buffer.total_chain, buffer.sbrked_remains);
2031 #endif /* DEBUGGING_MSTATS */
2035 #ifdef USE_PERL_SBRK
2037 # if defined(__MACHTEN_PPC__) || defined(NeXT) || defined(__NeXT__) || defined(PURIFY)
2038 # define PERL_SBRK_VIA_MALLOC
2041 # ifdef PERL_SBRK_VIA_MALLOC
2043 /* it may seem schizophrenic to use perl's malloc and let it call system */
2044 /* malloc, the reason for that is only the 3.2 version of the OS that had */
2045 /* frequent core dumps within nxzonefreenolock. This sbrk routine put an */
2046 /* end to the cores */
2048 # ifndef SYSTEM_ALLOC
2049 # define SYSTEM_ALLOC(a) malloc(a)
2051 # ifndef SYSTEM_ALLOC_ALIGNMENT
2052 # define SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES
2055 # endif /* PERL_SBRK_VIA_MALLOC */
2057 static IV Perl_sbrk_oldchunk;
2058 static long Perl_sbrk_oldsize;
2060 # define PERLSBRK_32_K (1<<15)
2061 # define PERLSBRK_64_K (1<<16)
2069 if (!size) return 0;
2071 reqsize = size; /* just for the DEBUG_m statement */
2074 size = (size + 0x7ff) & ~0x7ff;
2076 if (size <= Perl_sbrk_oldsize) {
2077 got = Perl_sbrk_oldchunk;
2078 Perl_sbrk_oldchunk += size;
2079 Perl_sbrk_oldsize -= size;
2081 if (size >= PERLSBRK_32_K) {
2084 size = PERLSBRK_64_K;
2087 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2088 size += NEEDED_ALIGNMENT - SYSTEM_ALLOC_ALIGNMENT;
2090 got = (IV)SYSTEM_ALLOC(size);
2091 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2092 got = (got + NEEDED_ALIGNMENT - 1) & ~(NEEDED_ALIGNMENT - 1);
2095 /* Chunk is small, register the rest for future allocs. */
2096 Perl_sbrk_oldchunk = got + reqsize;
2097 Perl_sbrk_oldsize = size - reqsize;
2101 DEBUG_m(PerlIO_printf(Perl_debug_log, "sbrk malloc size %ld (reqsize %ld), left size %ld, give addr 0x%"UVxf"\n",
2102 size, reqsize, Perl_sbrk_oldsize, PTR2UV(got)));
2107 #endif /* ! defined USE_PERL_SBRK */