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 # Error reporting function
150 warn(format, arg) fprintf(stderr, idem)
152 # Locking/unlocking for MT operation
153 MALLOC_LOCK MUTEX_LOCK_NOCONTEXT(&PL_malloc_mutex)
154 MALLOC_UNLOCK MUTEX_UNLOCK_NOCONTEXT(&PL_malloc_mutex)
156 # Locking/unlocking mutex for MT operation
161 #ifndef NO_FANCY_MALLOC
162 # ifndef SMALL_BUCKET_VIA_TABLE
163 # define SMALL_BUCKET_VIA_TABLE
165 # ifndef BUCKETS_ROOT2
166 # define BUCKETS_ROOT2
168 # ifndef IGNORE_SMALL_BAD_FREE
169 # define IGNORE_SMALL_BAD_FREE
173 #ifndef PLAIN_MALLOC /* Bulk enable features */
177 # ifndef TWO_POT_OPTIMIZE
178 # define TWO_POT_OPTIMIZE
180 # if defined(PERL_CORE) && !defined(PERL_EMERGENCY_SBRK)
181 # define PERL_EMERGENCY_SBRK
183 # if defined(PERL_CORE) && !defined(DEBUGGING_MSTATS)
184 # define DEBUGGING_MSTATS
188 #define MIN_BUC_POW2 (sizeof(void*) > 4 ? 3 : 2) /* Allow for 4-byte arena. */
189 #define MIN_BUCKET (MIN_BUC_POW2 * BUCKETS_PER_POW2)
191 #if !(defined(I286) || defined(atarist) || defined(__MINT__))
192 /* take 2k unless the block is bigger than that */
193 # define LOG_OF_MIN_ARENA 11
195 /* take 16k unless the block is bigger than that
196 (80286s like large segments!), probably good on the atari too */
197 # define LOG_OF_MIN_ARENA 14
201 # if defined(DEBUGGING) && !defined(NO_RCHECK)
204 # if defined(RCHECK) && defined(IGNORE_SMALL_BAD_FREE)
205 # undef IGNORE_SMALL_BAD_FREE
208 * malloc.c (Caltech) 2/21/82
209 * Chris Kingsley, kingsley@cit-20.
211 * This is a very fast storage allocator. It allocates blocks of a small
212 * number of different sizes, and keeps free lists of each size. Blocks that
213 * don't exactly fit are passed up to the next larger size. In this
214 * implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long.
215 * If PACK_MALLOC is defined, small blocks are 2^n bytes long.
216 * This is designed for use in a program that uses vast quantities of memory,
217 * but bombs when it runs out.
219 * Modifications Copyright Ilya Zakharevich 1996-99.
221 * Still very quick, but much more thrifty. (Std config is 10% slower
222 * than it was, and takes 67% of old heap size for typical usage.)
224 * Allocations of small blocks are now table-driven to many different
225 * buckets. Sizes of really big buckets are increased to accomodata
226 * common size=power-of-2 blocks. Running-out-of-memory is made into
227 * an exception. Deeply configurable and thread-safe.
233 # define PERL_IN_MALLOC_C
235 # if defined(PERL_IMPLICIT_CONTEXT)
236 # define croak Perl_croak_nocontext
237 # define warn Perl_warn_nocontext
241 # include "../EXTERN.h"
242 # include "../perl.h"
249 # define Malloc_t void *
255 # define MEM_SIZE unsigned long
258 # define LONG_MAX 0x7FFFFFFF
261 # define UV unsigned long
264 # define caddr_t char *
269 # define Copy(s,d,n,t) (void)memcpy((char*)(d),(char*)(s), (n) * sizeof(t))
270 # define PerlEnv_getenv getenv
271 # define PerlIO_printf fprintf
272 # define PerlIO_stderr() stderr
274 # ifndef croak /* make depend */
275 # define croak(mess, arg) (warn((mess), (arg)), exit(1))
278 # define warn(mess, arg) fprintf(stderr, (mess), (arg))
290 # define dTHX extern int Perl___notused
291 # define WITH_THX(s) s
293 # ifndef PERL_GET_INTERP
294 # define PERL_GET_INTERP PL_curinterp
297 # define Perl_malloc malloc
300 # define Perl_mfree free
302 # ifndef Perl_realloc
303 # define Perl_realloc realloc
306 # define Perl_calloc calloc
309 # define Perl_strdup strdup
314 # define MUTEX_LOCK(l)
318 # define MUTEX_UNLOCK(l)
322 # define MALLOC_LOCK MUTEX_LOCK_NOCONTEXT(&PL_malloc_mutex)
325 #ifndef MALLOC_UNLOCK
326 # define MALLOC_UNLOCK MUTEX_UNLOCK_NOCONTEXT(&PL_malloc_mutex)
329 # ifndef fatalcroak /* make depend */
330 # define fatalcroak(mess) (write(2, (mess), strlen(mess)), exit(2))
335 # define DEBUG_m(a) \
337 if (PERL_GET_INTERP) { dTHX; if (PL_debug & 128) { a; } } \
341 #ifdef PERL_IMPLICIT_CONTEXT
342 # define PERL_IS_ALIVE aTHX
344 # define PERL_IS_ALIVE TRUE
351 * The memory is broken into "blocks" which occupy multiples of 2K (and
352 * generally speaking, have size "close" to a power of 2). The addresses
353 * of such *unused* blocks are kept in nextf[i] with big enough i. (nextf
354 * is an array of linked lists.) (Addresses of used blocks are not known.)
356 * Moreover, since the algorithm may try to "bite" smaller blocks out
357 * of unused bigger ones, there are also regions of "irregular" size,
358 * managed separately, by a linked list chunk_chain.
360 * The third type of storage is the sbrk()ed-but-not-yet-used space, its
361 * end and size are kept in last_sbrk_top and sbrked_remains.
363 * Growing blocks "in place":
364 * ~~~~~~~~~~~~~~~~~~~~~~~~~
365 * The address of the block with the greatest address is kept in last_op
366 * (if not known, last_op is 0). If it is known that the memory above
367 * last_op is not continuous, or contains a chunk from chunk_chain,
368 * last_op is set to 0.
370 * The chunk with address last_op may be grown by expanding into
371 * sbrk()ed-but-not-yet-used space, or trying to sbrk() more continuous
374 * Management of last_op:
375 * ~~~~~~~~~~~~~~~~~~~~~
377 * free() never changes the boundaries of blocks, so is not relevant.
379 * The only way realloc() may change the boundaries of blocks is if it
380 * grows a block "in place". However, in the case of success such a
381 * chunk is automatically last_op, and it remains last_op. In the case
382 * of failure getpages_adjacent() clears last_op.
384 * malloc() may change blocks by calling morecore() only.
386 * morecore() may create new blocks by:
387 * a) biting pieces from chunk_chain (cannot create one above last_op);
388 * b) biting a piece from an unused block (if block was last_op, this
389 * may create a chunk from chain above last_op, thus last_op is
390 * invalidated in such a case).
391 * c) biting of sbrk()ed-but-not-yet-used space. This creates
392 * a block which is last_op.
393 * d) Allocating new pages by calling getpages();
395 * getpages() creates a new block. It marks last_op at the bottom of
396 * the chunk of memory it returns.
398 * Active pages footprint:
399 * ~~~~~~~~~~~~~~~~~~~~~~
400 * Note that we do not need to traverse the lists in nextf[i], just take
401 * the first element of this list. However, we *need* to traverse the
402 * list in chunk_chain, but most the time it should be a very short one,
403 * so we do not step on a lot of pages we are not going to use.
407 * get_from_bigger_buckets(): forget to increment price => Quite
411 /* I don't much care whether these are defined in sys/types.h--LAW */
413 #define u_char unsigned char
414 #define u_int unsigned int
416 * I removed the definition of u_bigint which appeared to be u_bigint = UV
417 * u_bigint was only used in TWOK_MASKED and TWOK_SHIFT
418 * where I have used PTR2UV. RMB
420 #define u_short unsigned short
422 /* 286 and atarist like big chunks, which gives too much overhead. */
423 #if (defined(RCHECK) || defined(I286) || defined(atarist) || defined(__MINT__)) && defined(PACK_MALLOC)
428 * The description below is applicable if PACK_MALLOC is not defined.
430 * The overhead on a block is at least 4 bytes. When free, this space
431 * contains a pointer to the next free block, and the bottom two bits must
432 * be zero. When in use, the first byte is set to MAGIC, and the second
433 * byte is the size index. The remaining bytes are for alignment.
434 * If range checking is enabled and the size of the block fits
435 * in two bytes, then the top two bytes hold the size of the requested block
436 * plus the range checking words, and the header word MINUS ONE.
439 union overhead *ov_next; /* when free */
440 #if MEM_ALIGNBYTES > 4
441 double strut; /* alignment problems */
444 u_char ovu_magic; /* magic number */
445 u_char ovu_index; /* bucket # */
447 u_short ovu_size; /* actual block size */
448 u_int ovu_rmagic; /* range magic number */
451 #define ov_magic ovu.ovu_magic
452 #define ov_index ovu.ovu_index
453 #define ov_size ovu.ovu_size
454 #define ov_rmagic ovu.ovu_rmagic
457 #define MAGIC 0xff /* magic # on accounting info */
458 #define RMAGIC 0x55555555 /* magic # on range info */
459 #define RMAGIC_C 0x55 /* magic # on range info */
462 # define RSLOP sizeof (u_int)
463 # ifdef TWO_POT_OPTIMIZE
464 # define MAX_SHORT_BUCKET (12 * BUCKETS_PER_POW2)
466 # define MAX_SHORT_BUCKET (13 * BUCKETS_PER_POW2)
472 #if !defined(PACK_MALLOC) && defined(BUCKETS_ROOT2)
473 # undef BUCKETS_ROOT2
477 # define BUCKET_TABLE_SHIFT 2
478 # define BUCKET_POW2_SHIFT 1
479 # define BUCKETS_PER_POW2 2
481 # define BUCKET_TABLE_SHIFT MIN_BUC_POW2
482 # define BUCKET_POW2_SHIFT 0
483 # define BUCKETS_PER_POW2 1
486 #if !defined(MEM_ALIGNBYTES) || ((MEM_ALIGNBYTES > 4) && !defined(STRICT_ALIGNMENT))
487 /* Figure out the alignment of void*. */
492 # define ALIGN_SMALL ((int)((caddr_t)&(((struct aligner*)0)->p)))
494 # define ALIGN_SMALL MEM_ALIGNBYTES
497 #define IF_ALIGN_8(yes,no) ((ALIGN_SMALL>4) ? (yes) : (no))
500 # define MAX_BUCKET_BY_TABLE 13
501 static u_short buck_size[MAX_BUCKET_BY_TABLE + 1] =
503 0, 0, 0, 0, 4, 4, 8, 12, 16, 24, 32, 48, 64, 80,
505 # define BUCKET_SIZE(i) ((i) % 2 ? buck_size[i] : (1 << ((i) >> BUCKET_POW2_SHIFT)))
506 # define BUCKET_SIZE_REAL(i) ((i) <= MAX_BUCKET_BY_TABLE \
508 : ((1 << ((i) >> BUCKET_POW2_SHIFT)) \
510 + POW2_OPTIMIZE_SURPLUS(i)))
512 # define BUCKET_SIZE(i) (1 << ((i) >> BUCKET_POW2_SHIFT))
513 # define BUCKET_SIZE_REAL(i) (BUCKET_SIZE(i) - MEM_OVERHEAD(i) + POW2_OPTIMIZE_SURPLUS(i))
518 /* In this case there are several possible layout of arenas depending
519 * on the size. Arenas are of sizes multiple to 2K, 2K-aligned, and
520 * have a size close to a power of 2.
522 * Arenas of the size >= 4K keep one chunk only. Arenas of size 2K
523 * may keep one chunk or multiple chunks. Here are the possible
526 * # One chunk only, chunksize 2^k + SOMETHING - ALIGN, k >= 11
528 * INDEX MAGIC1 UNUSED CHUNK1
530 * # Multichunk with sanity checking and chunksize 2^k-ALIGN, k>7
532 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 CHUNK2 CHUNK3 ...
534 * # Multichunk with sanity checking and size 2^k-ALIGN, k=7
536 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 UNUSED CHUNK2 CHUNK3 ...
538 * # Multichunk with sanity checking and size up to 80
540 * INDEX UNUSED MAGIC1 UNUSED MAGIC2 UNUSED ... CHUNK1 CHUNK2 CHUNK3 ...
542 * # No sanity check (usually up to 48=byte-long buckets)
543 * INDEX UNUSED CHUNK1 CHUNK2 ...
545 * Above INDEX and MAGIC are one-byte-long. Sizes of UNUSED are
546 * appropriate to keep algorithms simple and memory aligned. INDEX
547 * encodes the size of the chunk, while MAGICn encodes state (used,
548 * free or non-managed-by-us-so-it-indicates-a-bug) of CHUNKn. MAGIC
549 * is used for sanity checking purposes only. SOMETHING is 0 or 4K
550 * (to make size of big CHUNK accomodate allocations for powers of two
553 * [There is no need to alignment between chunks, since C rules ensure
554 * that structs which need 2^k alignment have sizeof which is
555 * divisible by 2^k. Thus as far as the last chunk is aligned at the
556 * end of the arena, and 2K-alignment does not contradict things,
557 * everything is going to be OK for sizes of chunks 2^n and 2^n +
558 * 2^k. Say, 80-bit buckets will be 16-bit aligned, and as far as we
559 * put allocations for requests in 65..80 range, all is fine.
561 * Note, however, that standard malloc() puts more strict
562 * requirements than the above C rules. Moreover, our algorithms of
563 * realloc() may break this idyll, but we suppose that realloc() does
564 * need not change alignment.]
566 * Is very important to make calculation of the offset of MAGICm as
567 * quick as possible, since it is done on each malloc()/free(). In
568 * fact it is so quick that it has quite little effect on the speed of
569 * doing malloc()/free(). [By default] We forego such calculations
570 * for small chunks, but only to save extra 3% of memory, not because
571 * of speed considerations.
573 * Here is the algorithm [which is the same for all the allocations
574 * schemes above], see OV_MAGIC(block,bucket). Let OFFSETm be the
575 * offset of the CHUNKm from the start of ARENA. Then offset of
576 * MAGICm is (OFFSET1 >> SHIFT) + ADDOFFSET. Here SHIFT and ADDOFFSET
577 * are numbers which depend on the size of the chunks only.
579 * Let as check some sanity conditions. Numbers OFFSETm>>SHIFT are
580 * different for all the chunks in the arena if 2^SHIFT is not greater
581 * than size of the chunks in the arena. MAGIC1 will not overwrite
582 * INDEX provided ADDOFFSET is >0 if OFFSET1 < 2^SHIFT. MAGIClast
583 * will not overwrite CHUNK1 if OFFSET1 > (OFFSETlast >> SHIFT) +
586 * Make SHIFT the maximal possible (there is no point in making it
587 * smaller). Since OFFSETlast is 2K - CHUNKSIZE, above restrictions
588 * give restrictions on OFFSET1 and on ADDOFFSET.
590 * In particular, for chunks of size 2^k with k>=6 we can put
591 * ADDOFFSET to be from 0 to 2^k - 2^(11-k), and have
592 * OFFSET1==chunksize. For chunks of size 80 OFFSET1 of 2K%80=48 is
593 * large enough to have ADDOFFSET between 1 and 16 (similarly for 96,
594 * when ADDOFFSET should be 1). In particular, keeping MAGICs for
595 * these sizes gives no additional size penalty.
597 * However, for chunks of size 2^k with k<=5 this gives OFFSET1 >=
598 * ADDOFSET + 2^(11-k). Keeping ADDOFFSET 0 allows for 2^(11-k)-2^(11-2k)
599 * chunks per arena. This is smaller than 2^(11-k) - 1 which are
600 * needed if no MAGIC is kept. [In fact, having a negative ADDOFFSET
601 * would allow for slightly more buckets per arena for k=2,3.]
603 * Similarly, for chunks of size 3/2*2^k with k<=5 MAGICs would span
604 * the area up to 2^(11-k)+ADDOFFSET. For k=4 this give optimal
605 * ADDOFFSET as -7..0. For k=3 ADDOFFSET can go up to 4 (with tiny
606 * savings for negative ADDOFFSET). For k=5 ADDOFFSET can go -1..16
607 * (with no savings for negative values).
609 * In particular, keeping ADDOFFSET 0 for sizes of chunks up to 2^6
610 * leads to tiny pessimizations in case of sizes 4, 8, 12, 24, and
611 * leads to no contradictions except for size=80 (or 96.)
613 * However, it also makes sense to keep no magic for sizes 48 or less.
614 * This is what we do. In this case one needs ADDOFFSET>=1 also for
615 * chunksizes 12, 24, and 48, unless one gets one less chunk per
618 * The algo of OV_MAGIC(block,bucket) keeps ADDOFFSET 0 until
619 * chunksize of 64, then makes it 1.
621 * This allows for an additional optimization: the above scheme leads
622 * to giant overheads for sizes 128 or more (one whole chunk needs to
623 * be sacrifised to keep INDEX). Instead we use chunks not of size
624 * 2^k, but of size 2^k-ALIGN. If we pack these chunks at the end of
625 * the arena, then the beginnings are still in different 2^k-long
626 * sections of the arena if k>=7 for ALIGN==4, and k>=8 if ALIGN=8.
627 * Thus for k>7 the above algo of calculating the offset of the magic
628 * will still give different answers for different chunks. And to
629 * avoid the overrun of MAGIC1 into INDEX, one needs ADDOFFSET of >=1.
630 * In the case k=7 we just move the first chunk an extra ALIGN
631 * backward inside the ARENA (this is done once per arena lifetime,
632 * thus is not a big overhead). */
633 # define MAX_PACKED_POW2 6
634 # define MAX_PACKED (MAX_PACKED_POW2 * BUCKETS_PER_POW2 + BUCKET_POW2_SHIFT)
635 # define MAX_POW2_ALGO ((1<<(MAX_PACKED_POW2 + 1)) - M_OVERHEAD)
636 # define TWOK_MASK ((1<<LOG_OF_MIN_ARENA) - 1)
637 # define TWOK_MASKED(x) (PTR2UV(x) & ~TWOK_MASK)
638 # define TWOK_SHIFT(x) (PTR2UV(x) & TWOK_MASK)
639 # define OV_INDEXp(block) (INT2PTR(u_char*,TWOK_MASKED(block)))
640 # define OV_INDEX(block) (*OV_INDEXp(block))
641 # define OV_MAGIC(block,bucket) (*(OV_INDEXp(block) + \
642 (TWOK_SHIFT(block)>> \
643 (bucket>>BUCKET_POW2_SHIFT)) + \
644 (bucket >= MIN_NEEDS_SHIFT ? 1 : 0)))
645 /* A bucket can have a shift smaller than it size, we need to
646 shift its magic number so it will not overwrite index: */
647 # ifdef BUCKETS_ROOT2
648 # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2 - 1) /* Shift 80 greater than chunk 64. */
650 # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2) /* Shift 128 greater than chunk 32. */
652 # define CHUNK_SHIFT 0
654 /* Number of active buckets of given ordinal. */
655 #ifdef IGNORE_SMALL_BAD_FREE
656 #define FIRST_BUCKET_WITH_CHECK (6 * BUCKETS_PER_POW2) /* 64 */
657 # define N_BLKS(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \
658 ? ((1<<LOG_OF_MIN_ARENA) - 1)/BUCKET_SIZE(bucket) \
661 # define N_BLKS(bucket) n_blks[bucket]
664 static u_short n_blks[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
666 # if BUCKETS_PER_POW2==1
668 (MIN_BUC_POW2==2 ? 384 : 0),
669 224, 120, 62, 31, 16, 8, 4, 2
672 (MIN_BUC_POW2==2 ? 384 : 0), (MIN_BUC_POW2==2 ? 384 : 0), /* 4, 4 */
673 224, 149, 120, 80, 62, 41, 31, 25, 16, 16, 8, 8, 4, 4, 2, 2
677 /* Shift of the first bucket with the given ordinal inside 2K chunk. */
678 #ifdef IGNORE_SMALL_BAD_FREE
679 # define BLK_SHIFT(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \
680 ? ((1<<LOG_OF_MIN_ARENA) \
681 - BUCKET_SIZE(bucket) * N_BLKS(bucket)) \
684 # define BLK_SHIFT(bucket) blk_shift[bucket]
687 static u_short blk_shift[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
689 # if BUCKETS_PER_POW2==1
691 (MIN_BUC_POW2==2 ? 512 : 0),
692 256, 128, 64, 64, /* 8 to 64 */
693 16*sizeof(union overhead),
694 8*sizeof(union overhead),
695 4*sizeof(union overhead),
696 2*sizeof(union overhead),
699 (MIN_BUC_POW2==2 ? 512 : 0), (MIN_BUC_POW2==2 ? 512 : 0),
700 256, 260, 128, 128, 64, 80, 64, 48, /* 8 to 96 */
701 16*sizeof(union overhead), 16*sizeof(union overhead),
702 8*sizeof(union overhead), 8*sizeof(union overhead),
703 4*sizeof(union overhead), 4*sizeof(union overhead),
704 2*sizeof(union overhead), 2*sizeof(union overhead),
708 # define NEEDED_ALIGNMENT 0x800 /* 2k boundaries */
709 # define WANTED_ALIGNMENT 0x800 /* 2k boundaries */
711 #else /* !PACK_MALLOC */
713 # define OV_MAGIC(block,bucket) (block)->ov_magic
714 # define OV_INDEX(block) (block)->ov_index
715 # define CHUNK_SHIFT 1
716 # define MAX_PACKED -1
717 # define NEEDED_ALIGNMENT MEM_ALIGNBYTES
718 # define WANTED_ALIGNMENT 0x400 /* 1k boundaries */
720 #endif /* !PACK_MALLOC */
722 #define M_OVERHEAD (sizeof(union overhead) + RSLOP)
725 # define MEM_OVERHEAD(bucket) \
726 (bucket <= MAX_PACKED ? 0 : M_OVERHEAD)
727 # ifdef SMALL_BUCKET_VIA_TABLE
728 # define START_SHIFTS_BUCKET ((MAX_PACKED_POW2 + 1) * BUCKETS_PER_POW2)
729 # define START_SHIFT MAX_PACKED_POW2
730 # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */
731 # define SIZE_TABLE_MAX 80
733 # define SIZE_TABLE_MAX 64
735 static char bucket_of[] =
737 # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */
738 /* 0 to 15 in 4-byte increments. */
739 (sizeof(void*) > 4 ? 6 : 5), /* 4/8, 5-th bucket for better reports */
741 IF_ALIGN_8(8,7), 8, /* 16/12, 16 */
742 9, 9, 10, 10, /* 24, 32 */
743 11, 11, 11, 11, /* 48 */
744 12, 12, 12, 12, /* 64 */
745 13, 13, 13, 13, /* 80 */
746 13, 13, 13, 13 /* 80 */
747 # else /* !BUCKETS_ROOT2 */
748 /* 0 to 15 in 4-byte increments. */
749 (sizeof(void*) > 4 ? 3 : 2),
755 # endif /* !BUCKETS_ROOT2 */
757 # else /* !SMALL_BUCKET_VIA_TABLE */
758 # define START_SHIFTS_BUCKET MIN_BUCKET
759 # define START_SHIFT (MIN_BUC_POW2 - 1)
760 # endif /* !SMALL_BUCKET_VIA_TABLE */
761 #else /* !PACK_MALLOC */
762 # define MEM_OVERHEAD(bucket) M_OVERHEAD
763 # ifdef SMALL_BUCKET_VIA_TABLE
764 # undef SMALL_BUCKET_VIA_TABLE
766 # define START_SHIFTS_BUCKET MIN_BUCKET
767 # define START_SHIFT (MIN_BUC_POW2 - 1)
768 #endif /* !PACK_MALLOC */
771 * Big allocations are often of the size 2^n bytes. To make them a
772 * little bit better, make blocks of size 2^n+pagesize for big n.
775 #ifdef TWO_POT_OPTIMIZE
777 # ifndef PERL_PAGESIZE
778 # define PERL_PAGESIZE 4096
780 # ifndef FIRST_BIG_POW2
781 # define FIRST_BIG_POW2 15 /* 32K, 16K is used too often. */
783 # define FIRST_BIG_BLOCK (1<<FIRST_BIG_POW2)
784 /* If this value or more, check against bigger blocks. */
785 # define FIRST_BIG_BOUND (FIRST_BIG_BLOCK - M_OVERHEAD)
786 /* If less than this value, goes into 2^n-overhead-block. */
787 # define LAST_SMALL_BOUND ((FIRST_BIG_BLOCK>>1) - M_OVERHEAD)
789 # define POW2_OPTIMIZE_ADJUST(nbytes) \
790 ((nbytes >= FIRST_BIG_BOUND) ? nbytes -= PERL_PAGESIZE : 0)
791 # define POW2_OPTIMIZE_SURPLUS(bucket) \
792 ((bucket >= FIRST_BIG_POW2 * BUCKETS_PER_POW2) ? PERL_PAGESIZE : 0)
794 #else /* !TWO_POT_OPTIMIZE */
795 # define POW2_OPTIMIZE_ADJUST(nbytes)
796 # define POW2_OPTIMIZE_SURPLUS(bucket) 0
797 #endif /* !TWO_POT_OPTIMIZE */
799 #if defined(HAS_64K_LIMIT) && defined(PERL_CORE)
800 # define BARK_64K_LIMIT(what,nbytes,size) \
801 if (nbytes > 0xffff) { \
802 PerlIO_printf(PerlIO_stderr(), \
803 "%s too large: %lx\n", what, size); \
806 #else /* !HAS_64K_LIMIT || !PERL_CORE */
807 # define BARK_64K_LIMIT(what,nbytes,size)
808 #endif /* !HAS_64K_LIMIT || !PERL_CORE */
811 # define MIN_SBRK 2048
815 # define FIRST_SBRK (48*1024)
818 /* Minimal sbrk in percents of what is already alloced. */
819 #ifndef MIN_SBRK_FRAC
820 # define MIN_SBRK_FRAC 3
823 #ifndef SBRK_ALLOW_FAILURES
824 # define SBRK_ALLOW_FAILURES 3
827 #ifndef SBRK_FAILURE_PRICE
828 # define SBRK_FAILURE_PRICE 50
831 #if defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)
834 # define BIG_SIZE (1<<16) /* 64K */
837 #ifdef I_MACH_CTHREADS
839 # define MUTEX_LOCK(m) STMT_START { if (*m) mutex_lock(*m); } STMT_END
841 # define MUTEX_UNLOCK(m) STMT_START { if (*m) mutex_unlock(*m); } STMT_END
844 static char *emergency_buffer;
845 static MEM_SIZE emergency_buffer_size;
847 static void morecore (register int bucket);
848 # if defined(DEBUGGING)
849 static void botch (char *diag, char *s);
851 static void add_to_chain (void *p, MEM_SIZE size, MEM_SIZE chip);
852 static Malloc_t emergency_sbrk (MEM_SIZE size);
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);
859 emergency_sbrk(MEM_SIZE size)
861 MEM_SIZE rsize = (((size - 1)>>LOG_OF_MIN_ARENA) + 1)<<LOG_OF_MIN_ARENA;
863 if (size >= BIG_SIZE) {
864 /* Give the possibility to recover: */
866 croak("Out of memory during \"large\" request for %i bytes", size);
869 if (emergency_buffer_size >= rsize) {
870 char *old = emergency_buffer;
872 emergency_buffer_size -= rsize;
873 emergency_buffer += rsize;
877 /* First offense, give a possibility to recover by dieing. */
878 /* No malloc involved here: */
879 GV **gvp = (GV**)hv_fetch(PL_defstash, "^M", 2, 0);
885 if (emergency_buffer_size) {
886 add_to_chain(emergency_buffer, emergency_buffer_size, 0);
887 emergency_buffer_size = 0;
888 emergency_buffer = Nullch;
891 if (!gvp) gvp = (GV**)hv_fetch(PL_defstash, "\015", 1, 0);
892 if (!gvp || !(sv = GvSV(*gvp)) || !SvPOK(sv)
893 || (SvLEN(sv) < (1<<LOG_OF_MIN_ARENA) - M_OVERHEAD)) {
896 return (char *)-1; /* Now die die die... */
898 /* Got it, now detach SvPV: */
900 /* Check alignment: */
901 if ((PTR2UV(pv) - sizeof(union overhead)) & (NEEDED_ALIGNMENT - 1)) {
902 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
903 return (char *)-1; /* die die die */
906 emergency_buffer = pv - sizeof(union overhead);
907 emergency_buffer_size = malloced_size(pv) + M_OVERHEAD;
910 SvCUR(sv) = SvLEN(sv) = 0;
914 croak("Out of memory during request for %i bytes", size);
919 #else /* !(defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)) */
920 # define emergency_sbrk(size) -1
921 #endif /* !(defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)) */
924 # define BITS_IN_PTR (8*PTRSIZE)
928 * nextf[i] is the pointer to the next free block of size 2^i. The
929 * smallest allocatable block is 8 bytes. The overhead information
930 * precedes the data area returned to the user.
932 #define NBUCKETS (BITS_IN_PTR*BUCKETS_PER_POW2 + 1)
933 static union overhead *nextf[NBUCKETS];
935 #if defined(PURIFY) && !defined(USE_PERL_SBRK)
936 # define USE_PERL_SBRK
940 #define sbrk(a) Perl_sbrk(a)
941 Malloc_t Perl_sbrk (int size);
943 #ifdef DONT_DECLARE_STD
948 extern Malloc_t sbrk(int);
952 #ifdef DEBUGGING_MSTATS
954 * nmalloc[i] is the difference between the number of mallocs and frees
955 * for a given block size.
957 static u_int nmalloc[NBUCKETS];
958 static u_int sbrk_slack;
959 static u_int start_slack;
962 static u_int goodsbrk;
966 #define ASSERT(p,diag) if (!(p)) botch(diag,STRINGIFY(p)); else
968 botch(char *diag, char *s)
971 PerlIO_printf(PerlIO_stderr(), "assertion botched (%s?): %s\n", diag, s);
975 #define ASSERT(p, diag)
979 Perl_malloc(register size_t nbytes)
981 register union overhead *p;
983 register MEM_SIZE shiftr;
985 #if defined(DEBUGGING) || defined(RCHECK)
986 MEM_SIZE size = nbytes;
989 BARK_64K_LIMIT("Allocation",nbytes,nbytes);
991 if ((long)nbytes < 0)
992 croak("%s", "panic: malloc");
996 * Convert amount of memory requested into
997 * closest block size stored in hash buckets
998 * which satisfies request. Account for
999 * space used per block for accounting.
1002 # ifdef SMALL_BUCKET_VIA_TABLE
1004 bucket = MIN_BUCKET;
1005 else if (nbytes <= SIZE_TABLE_MAX) {
1006 bucket = bucket_of[(nbytes - 1) >> BUCKET_TABLE_SHIFT];
1011 if (nbytes <= MAX_POW2_ALGO) goto do_shifts;
1016 POW2_OPTIMIZE_ADJUST(nbytes);
1017 nbytes += M_OVERHEAD;
1018 nbytes = (nbytes + 3) &~ 3;
1020 shiftr = (nbytes - 1) >> START_SHIFT;
1021 bucket = START_SHIFTS_BUCKET;
1022 /* apart from this loop, this is O(1) */
1023 while (shiftr >>= 1)
1024 bucket += BUCKETS_PER_POW2;
1028 * If nothing in hash bucket right now,
1029 * request more memory from the system.
1031 if (nextf[bucket] == NULL)
1033 if ((p = nextf[bucket]) == NULL) {
1039 PerlIO_puts(PerlIO_stderr(),"Out of memory!\n");
1047 DEBUG_m(PerlIO_printf(Perl_debug_log,
1048 "0x%"UVxf": (%05lu) malloc %ld bytes\n",
1049 PTR2UV(p+1), (unsigned long)(PL_an++),
1052 /* remove from linked list */
1054 if ((PTR2UV(p)) & (MEM_ALIGNBYTES - 1)) {
1056 PerlIO_printf(PerlIO_stderr(),
1057 "Unaligned pointer in the free chain 0x%"UVxf"\n",
1060 if ((PTR2UV(p->ov_next)) & (MEM_ALIGNBYTES - 1)) {
1062 PerlIO_printf(PerlIO_stderr(),
1063 "Unaligned `next' pointer in the free "
1064 "chain 0x"UVxf" at 0x%"UVxf"\n",
1065 PTR2UV(p->ov_next), PTR2UV(p));
1068 nextf[bucket] = p->ov_next;
1072 #ifdef IGNORE_SMALL_BAD_FREE
1073 if (bucket >= FIRST_BUCKET_WITH_CHECK)
1075 OV_MAGIC(p, bucket) = MAGIC;
1077 OV_INDEX(p) = bucket;
1081 * Record allocated size of block and
1082 * bound space with magic numbers.
1084 p->ov_rmagic = RMAGIC;
1085 if (bucket <= MAX_SHORT_BUCKET) {
1088 nbytes = size + M_OVERHEAD;
1089 p->ov_size = nbytes - 1;
1090 if ((i = nbytes & 3)) {
1093 *((char *)((caddr_t)p + nbytes - RSLOP + i)) = RMAGIC_C;
1095 nbytes = (nbytes + 3) &~ 3;
1096 *((u_int *)((caddr_t)p + nbytes - RSLOP)) = RMAGIC;
1099 return ((Malloc_t)(p + CHUNK_SHIFT));
1102 static char *last_sbrk_top;
1103 static char *last_op; /* This arena can be easily extended. */
1104 static int sbrked_remains;
1105 static int sbrk_good = SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE;
1107 #ifdef DEBUGGING_MSTATS
1111 struct chunk_chain_s {
1112 struct chunk_chain_s *next;
1115 static struct chunk_chain_s *chunk_chain;
1116 static int n_chunks;
1117 static char max_bucket;
1119 /* Cutoff a piece of one of the chunks in the chain. Prefer smaller chunk. */
1121 get_from_chain(MEM_SIZE size)
1123 struct chunk_chain_s *elt = chunk_chain, **oldp = &chunk_chain;
1124 struct chunk_chain_s **oldgoodp = NULL;
1125 long min_remain = LONG_MAX;
1128 if (elt->size >= size) {
1129 long remains = elt->size - size;
1130 if (remains >= 0 && remains < min_remain) {
1132 min_remain = remains;
1138 oldp = &( elt->next );
1141 if (!oldgoodp) return NULL;
1143 void *ret = *oldgoodp;
1144 struct chunk_chain_s *next = (*oldgoodp)->next;
1146 *oldgoodp = (struct chunk_chain_s *)((char*)ret + size);
1147 (*oldgoodp)->size = min_remain;
1148 (*oldgoodp)->next = next;
1151 void *ret = *oldgoodp;
1152 *oldgoodp = (*oldgoodp)->next;
1159 add_to_chain(void *p, MEM_SIZE size, MEM_SIZE chip)
1161 struct chunk_chain_s *next = chunk_chain;
1162 char *cp = (char*)p;
1165 chunk_chain = (struct chunk_chain_s *)cp;
1166 chunk_chain->size = size - chip;
1167 chunk_chain->next = next;
1172 get_from_bigger_buckets(int bucket, MEM_SIZE size)
1175 static int bucketprice[NBUCKETS];
1176 while (bucket <= max_bucket) {
1177 /* We postpone stealing from bigger buckets until we want it
1179 if (nextf[bucket] && bucketprice[bucket]++ >= price) {
1181 void *ret = (void*)(nextf[bucket] - 1 + CHUNK_SHIFT);
1182 bucketprice[bucket] = 0;
1183 if (((char*)nextf[bucket]) - M_OVERHEAD == last_op) {
1184 last_op = NULL; /* Disable optimization */
1186 nextf[bucket] = nextf[bucket]->ov_next;
1187 #ifdef DEBUGGING_MSTATS
1189 start_slack -= M_OVERHEAD;
1191 add_to_chain(ret, (BUCKET_SIZE(bucket) +
1192 POW2_OPTIMIZE_SURPLUS(bucket)),
1201 static union overhead *
1202 getpages(MEM_SIZE needed, int *nblksp, int bucket)
1204 /* Need to do (possibly expensive) system call. Try to
1205 optimize it for rare calling. */
1206 MEM_SIZE require = needed - sbrked_remains;
1208 union overhead *ovp;
1211 if (sbrk_good > 0) {
1212 if (!last_sbrk_top && require < FIRST_SBRK)
1213 require = FIRST_SBRK;
1214 else if (require < MIN_SBRK) require = MIN_SBRK;
1216 if (require < goodsbrk * MIN_SBRK_FRAC / 100)
1217 require = goodsbrk * MIN_SBRK_FRAC / 100;
1218 require = ((require - 1 + MIN_SBRK) / MIN_SBRK) * MIN_SBRK;
1225 DEBUG_m(PerlIO_printf(Perl_debug_log,
1226 "sbrk(%ld) for %ld-byte-long arena\n",
1227 (long)require, (long) needed));
1228 cp = (char *)sbrk(require);
1229 #ifdef DEBUGGING_MSTATS
1232 if (cp == last_sbrk_top) {
1233 /* Common case, anything is fine. */
1235 ovp = (union overhead *) (cp - sbrked_remains);
1236 last_op = cp - sbrked_remains;
1237 sbrked_remains = require - (needed - sbrked_remains);
1238 } else if (cp == (char *)-1) { /* no more room! */
1239 ovp = (union overhead *)emergency_sbrk(needed);
1240 if (ovp == (union overhead *)-1)
1242 if (((char*)ovp) > last_op) { /* Cannot happen with current emergency_sbrk() */
1246 } else { /* Non-continuous or first sbrk(). */
1247 long add = sbrked_remains;
1250 if (sbrked_remains) { /* Put rest into chain, we
1251 cannot use it right now. */
1252 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1256 /* Second, check alignment. */
1259 #if !defined(atarist) && !defined(__MINT__) /* on the atari we dont have to worry about this */
1260 # ifndef I286 /* The sbrk(0) call on the I286 always returns the next segment */
1261 /* WANTED_ALIGNMENT may be more than NEEDED_ALIGNMENT, but this may
1262 improve performance of memory access. */
1263 if (PTR2UV(cp) & (WANTED_ALIGNMENT - 1)) { /* Not aligned. */
1264 slack = WANTED_ALIGNMENT - (PTR2UV(cp) & (WANTED_ALIGNMENT - 1));
1268 #endif /* !atarist && !MINT */
1271 DEBUG_m(PerlIO_printf(Perl_debug_log,
1272 "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",
1273 (long)add, (long) slack,
1274 (long) sbrked_remains));
1275 newcp = (char *)sbrk(add);
1276 #if defined(DEBUGGING_MSTATS)
1280 if (newcp != cp + require) {
1281 /* Too bad: even rounding sbrk() is not continuous.*/
1282 DEBUG_m(PerlIO_printf(Perl_debug_log,
1283 "failed to fix bad sbrk()\n"));
1287 fatalcroak("panic: Off-page sbrk\n");
1290 if (sbrked_remains) {
1292 #if defined(DEBUGGING_MSTATS)
1293 sbrk_slack += require;
1296 DEBUG_m(PerlIO_printf(Perl_debug_log,
1297 "straight sbrk(%ld)\n",
1299 cp = (char *)sbrk(require);
1300 #ifdef DEBUGGING_MSTATS
1303 if (cp == (char *)-1)
1306 sbrk_good = -1; /* Disable optimization!
1307 Continue with not-aligned... */
1310 require += sbrked_remains;
1314 if (last_sbrk_top) {
1315 sbrk_good -= SBRK_FAILURE_PRICE;
1318 ovp = (union overhead *) cp;
1320 * Round up to minimum allocation size boundary
1321 * and deduct from block count to reflect.
1324 # if NEEDED_ALIGNMENT > MEM_ALIGNBYTES
1325 if (PTR2UV(ovp) & (NEEDED_ALIGNMENT - 1))
1326 fatalcroak("Misalignment of sbrk()\n");
1329 #ifndef I286 /* Again, this should always be ok on an 80286 */
1330 if (PTR2UV(ovp) & (MEM_ALIGNBYTES - 1)) {
1331 DEBUG_m(PerlIO_printf(Perl_debug_log,
1332 "fixing sbrk(): %d bytes off machine alignement\n",
1333 (int)(PTR2UV(ovp) & (MEM_ALIGNBYTES - 1))));
1334 ovp = INT2PTR(union overhead *,(PTR2UV(ovp) + MEM_ALIGNBYTES) &
1335 (MEM_ALIGNBYTES - 1));
1337 # if defined(DEBUGGING_MSTATS)
1338 /* This is only approx. if TWO_POT_OPTIMIZE: */
1339 sbrk_slack += (1 << (bucket >> BUCKET_POW2_SHIFT));
1343 ; /* Finish `else' */
1344 sbrked_remains = require - needed;
1347 last_sbrk_top = cp + require;
1348 #ifdef DEBUGGING_MSTATS
1349 goodsbrk += require;
1355 getpages_adjacent(MEM_SIZE require)
1357 if (require <= sbrked_remains) {
1358 sbrked_remains -= require;
1362 require -= sbrked_remains;
1363 /* We do not try to optimize sbrks here, we go for place. */
1364 cp = (char*) sbrk(require);
1365 #ifdef DEBUGGING_MSTATS
1367 goodsbrk += require;
1369 if (cp == last_sbrk_top) {
1371 last_sbrk_top = cp + require;
1373 if (cp == (char*)-1) { /* Out of memory */
1374 #ifdef DEBUGGING_MSTATS
1375 goodsbrk -= require;
1379 /* Report the failure: */
1381 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1383 add_to_chain((void*)cp, require, 0);
1384 sbrk_good -= SBRK_FAILURE_PRICE;
1396 * Allocate more memory to the indicated bucket.
1399 morecore(register int bucket)
1401 register union overhead *ovp;
1402 register int rnu; /* 2^rnu bytes will be requested */
1403 int nblks; /* become nblks blocks of the desired size */
1404 register MEM_SIZE siz, needed;
1408 if (bucket == sizeof(MEM_SIZE)*8*BUCKETS_PER_POW2) {
1410 croak("%s", "Out of memory during ridiculously large request");
1412 if (bucket > max_bucket)
1413 max_bucket = bucket;
1415 rnu = ( (bucket <= (LOG_OF_MIN_ARENA << BUCKET_POW2_SHIFT))
1417 : (bucket >> BUCKET_POW2_SHIFT) );
1418 /* This may be overwritten later: */
1419 nblks = 1 << (rnu - (bucket >> BUCKET_POW2_SHIFT)); /* how many blocks to get */
1420 needed = ((MEM_SIZE)1 << rnu) + POW2_OPTIMIZE_SURPLUS(bucket);
1421 if (nextf[rnu << BUCKET_POW2_SHIFT]) { /* 2048b bucket. */
1422 ovp = nextf[rnu << BUCKET_POW2_SHIFT] - 1 + CHUNK_SHIFT;
1423 nextf[rnu << BUCKET_POW2_SHIFT]
1424 = nextf[rnu << BUCKET_POW2_SHIFT]->ov_next;
1425 #ifdef DEBUGGING_MSTATS
1426 nmalloc[rnu << BUCKET_POW2_SHIFT]--;
1427 start_slack -= M_OVERHEAD;
1429 DEBUG_m(PerlIO_printf(Perl_debug_log,
1430 "stealing %ld bytes from %ld arena\n",
1431 (long) needed, (long) rnu << BUCKET_POW2_SHIFT));
1432 } else if (chunk_chain
1433 && (ovp = (union overhead*) get_from_chain(needed))) {
1434 DEBUG_m(PerlIO_printf(Perl_debug_log,
1435 "stealing %ld bytes from chain\n",
1437 } else if ( (ovp = (union overhead*)
1438 get_from_bigger_buckets((rnu << BUCKET_POW2_SHIFT) + 1,
1440 DEBUG_m(PerlIO_printf(Perl_debug_log,
1441 "stealing %ld bytes from bigger buckets\n",
1443 } else if (needed <= sbrked_remains) {
1444 ovp = (union overhead *)(last_sbrk_top - sbrked_remains);
1445 sbrked_remains -= needed;
1446 last_op = (char*)ovp;
1448 ovp = getpages(needed, &nblks, bucket);
1454 * Add new memory allocated to that on
1455 * free list for this hash bucket.
1457 siz = BUCKET_SIZE(bucket);
1459 *(u_char*)ovp = bucket; /* Fill index. */
1460 if (bucket <= MAX_PACKED) {
1461 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1462 nblks = N_BLKS(bucket);
1463 # ifdef DEBUGGING_MSTATS
1464 start_slack += BLK_SHIFT(bucket);
1466 } else if (bucket < LOG_OF_MIN_ARENA * BUCKETS_PER_POW2) {
1467 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1468 siz -= sizeof(union overhead);
1469 } else ovp++; /* One chunk per block. */
1470 #endif /* PACK_MALLOC */
1471 nextf[bucket] = ovp;
1472 #ifdef DEBUGGING_MSTATS
1473 nmalloc[bucket] += nblks;
1474 if (bucket > MAX_PACKED) {
1475 start_slack += M_OVERHEAD * nblks;
1478 while (--nblks > 0) {
1479 ovp->ov_next = (union overhead *)((caddr_t)ovp + siz);
1480 ovp = (union overhead *)((caddr_t)ovp + siz);
1482 /* Not all sbrks return zeroed memory.*/
1483 ovp->ov_next = (union overhead *)NULL;
1485 if (bucket == 7*BUCKETS_PER_POW2) { /* Special case, explanation is above. */
1486 union overhead *n_op = nextf[7*BUCKETS_PER_POW2]->ov_next;
1487 nextf[7*BUCKETS_PER_POW2] =
1488 (union overhead *)((caddr_t)nextf[7*BUCKETS_PER_POW2]
1489 - sizeof(union overhead));
1490 nextf[7*BUCKETS_PER_POW2]->ov_next = n_op;
1492 #endif /* !PACK_MALLOC */
1496 Perl_mfree(void *mp)
1498 register MEM_SIZE size;
1499 register union overhead *ovp;
1500 char *cp = (char*)mp;
1505 DEBUG_m(PerlIO_printf(Perl_debug_log,
1506 "0x%"UVxf": (%05lu) free\n",
1507 PTR2UV(cp), (unsigned long)(PL_an++)));
1511 ovp = (union overhead *)((caddr_t)cp
1512 - sizeof (union overhead) * CHUNK_SHIFT);
1514 bucket = OV_INDEX(ovp);
1516 #ifdef IGNORE_SMALL_BAD_FREE
1517 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
1518 && (OV_MAGIC(ovp, bucket) != MAGIC))
1520 if (OV_MAGIC(ovp, bucket) != MAGIC)
1523 static int bad_free_warn = -1;
1524 if (bad_free_warn == -1) {
1526 char *pbf = PerlEnv_getenv("PERL_BADFREE");
1527 bad_free_warn = (pbf) ? atoi(pbf) : 1;
1535 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1536 Perl_warner(aTHX_ WARN_MALLOC, "%s free() ignored",
1537 ovp->ov_rmagic == RMAGIC - 1 ?
1538 "Duplicate" : "Bad");
1541 warn("%s free() ignored",
1542 ovp->ov_rmagic == RMAGIC - 1 ? "Duplicate" : "Bad");
1548 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1549 Perl_warner(aTHX_ WARN_MALLOC, "%s", "Bad free() ignored");
1552 warn("%s", "Bad free() ignored");
1555 return; /* sanity */
1558 ASSERT(ovp->ov_rmagic == RMAGIC, "chunk's head overwrite");
1559 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
1561 MEM_SIZE nbytes = ovp->ov_size + 1;
1563 if ((i = nbytes & 3)) {
1566 ASSERT(*((char *)((caddr_t)ovp + nbytes - RSLOP + i))
1567 == RMAGIC_C, "chunk's tail overwrite");
1570 nbytes = (nbytes + 3) &~ 3;
1571 ASSERT(*(u_int *)((caddr_t)ovp + nbytes - RSLOP) == RMAGIC, "chunk's tail overwrite");
1573 ovp->ov_rmagic = RMAGIC - 1;
1575 ASSERT(OV_INDEX(ovp) < NBUCKETS, "chunk's head overwrite");
1576 size = OV_INDEX(ovp);
1579 ovp->ov_next = nextf[size];
1584 /* There is no need to do any locking in realloc (with an exception of
1585 trying to grow in place if we are at the end of the chain).
1586 If somebody calls us from a different thread with the same address,
1587 we are sole anyway. */
1590 Perl_realloc(void *mp, size_t nbytes)
1592 register MEM_SIZE onb;
1593 union overhead *ovp;
1596 register int bucket;
1597 int incr; /* 1 if does not fit, -1 if "easily" fits in a
1598 smaller bucket, otherwise 0. */
1599 char *cp = (char*)mp;
1601 #if defined(DEBUGGING) || !defined(PERL_CORE)
1602 MEM_SIZE size = nbytes;
1604 if ((long)nbytes < 0)
1605 croak("%s", "panic: realloc");
1608 BARK_64K_LIMIT("Reallocation",nbytes,size);
1610 return Perl_malloc(nbytes);
1612 ovp = (union overhead *)((caddr_t)cp
1613 - sizeof (union overhead) * CHUNK_SHIFT);
1614 bucket = OV_INDEX(ovp);
1616 #ifdef IGNORE_SMALL_BAD_FREE
1617 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
1618 && (OV_MAGIC(ovp, bucket) != MAGIC))
1620 if (OV_MAGIC(ovp, bucket) != MAGIC)
1623 static int bad_free_warn = -1;
1624 if (bad_free_warn == -1) {
1626 char *pbf = PerlEnv_getenv("PERL_BADFREE");
1627 bad_free_warn = (pbf) ? atoi(pbf) : 1;
1635 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1636 Perl_warner(aTHX_ WARN_MALLOC, "%srealloc() %signored",
1637 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
1638 ovp->ov_rmagic == RMAGIC - 1
1639 ? "of freed memory " : "");
1642 warn("%srealloc() %signored",
1643 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
1644 ovp->ov_rmagic == RMAGIC - 1 ? "of freed memory " : "");
1650 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1651 Perl_warner(aTHX_ WARN_MALLOC, "%s",
1652 "Bad realloc() ignored");
1655 warn("%s", "Bad realloc() ignored");
1658 return Nullch; /* sanity */
1661 onb = BUCKET_SIZE_REAL(bucket);
1663 * avoid the copy if same size block.
1664 * We are not agressive with boundary cases. Note that it might
1665 * (for a small number of cases) give false negative if
1666 * both new size and old one are in the bucket for
1667 * FIRST_BIG_POW2, but the new one is near the lower end.
1669 * We do not try to go to 1.5 times smaller bucket so far.
1671 if (nbytes > onb) incr = 1;
1673 #ifdef DO_NOT_TRY_HARDER_WHEN_SHRINKING
1674 if ( /* This is a little bit pessimal if PACK_MALLOC: */
1675 nbytes > ( (onb >> 1) - M_OVERHEAD )
1676 # ifdef TWO_POT_OPTIMIZE
1677 || (bucket == FIRST_BIG_POW2 && nbytes >= LAST_SMALL_BOUND )
1680 #else /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
1681 prev_bucket = ( (bucket > MAX_PACKED + 1)
1682 ? bucket - BUCKETS_PER_POW2
1684 if (nbytes > BUCKET_SIZE_REAL(prev_bucket))
1685 #endif /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
1689 #ifdef STRESS_REALLOC
1696 * Record new allocated size of block and
1697 * bound space with magic numbers.
1699 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
1700 int i, nb = ovp->ov_size + 1;
1705 ASSERT(*((char *)((caddr_t)ovp + nb - RSLOP + i)) == RMAGIC_C, "chunk's tail overwrite");
1709 ASSERT(*(u_int *)((caddr_t)ovp + nb - RSLOP) == RMAGIC, "chunk's tail overwrite");
1711 * Convert amount of memory requested into
1712 * closest block size stored in hash buckets
1713 * which satisfies request. Account for
1714 * space used per block for accounting.
1716 nbytes += M_OVERHEAD;
1717 ovp->ov_size = nbytes - 1;
1718 if ((i = nbytes & 3)) {
1721 *((char *)((caddr_t)ovp + nbytes - RSLOP + i))
1724 nbytes = (nbytes + 3) &~ 3;
1725 *((u_int *)((caddr_t)ovp + nbytes - RSLOP)) = RMAGIC;
1729 DEBUG_m(PerlIO_printf(Perl_debug_log,
1730 "0x%"UVxf": (%05lu) realloc %ld bytes inplace\n",
1731 PTR2UV(res),(unsigned long)(PL_an++),
1733 } else if (incr == 1 && (cp - M_OVERHEAD == last_op)
1734 && (onb > (1 << LOG_OF_MIN_ARENA))) {
1735 MEM_SIZE require, newarena = nbytes, pow;
1738 POW2_OPTIMIZE_ADJUST(newarena);
1739 newarena = newarena + M_OVERHEAD;
1740 /* newarena = (newarena + 3) &~ 3; */
1741 shiftr = (newarena - 1) >> LOG_OF_MIN_ARENA;
1742 pow = LOG_OF_MIN_ARENA + 1;
1743 /* apart from this loop, this is O(1) */
1744 while (shiftr >>= 1)
1746 newarena = (1 << pow) + POW2_OPTIMIZE_SURPLUS(pow * BUCKETS_PER_POW2);
1747 require = newarena - onb - M_OVERHEAD;
1750 if (cp - M_OVERHEAD == last_op /* We *still* are the last chunk */
1751 && getpages_adjacent(require)) {
1752 #ifdef DEBUGGING_MSTATS
1754 nmalloc[pow * BUCKETS_PER_POW2]++;
1756 *(cp - M_OVERHEAD) = pow * BUCKETS_PER_POW2; /* Fill index. */
1765 DEBUG_m(PerlIO_printf(Perl_debug_log,
1766 "0x%"UVxf": (%05lu) realloc %ld bytes the hard way\n",
1767 PTR2UV(cp),(unsigned long)(PL_an++),
1769 if ((res = (char*)Perl_malloc(nbytes)) == NULL)
1771 if (cp != res) /* common optimization */
1772 Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char);
1775 return ((Malloc_t)res);
1779 Perl_calloc(register size_t elements, register size_t size)
1781 long sz = elements * size;
1782 Malloc_t p = Perl_malloc(sz);
1785 memset((void*)p, 0, sz);
1791 Perl_strdup(const char *s)
1793 MEM_SIZE l = strlen(s);
1794 char *s1 = (char *)Perl_malloc(l+1);
1796 Copy(s, s1, (MEM_SIZE)(l+1), char);
1802 Perl_putenv(char *a)
1804 /* Sometimes system's putenv conflicts with my_setenv() - this is system
1805 malloc vs Perl's free(). */
1812 while (*val && *val != '=')
1817 if (l < sizeof(buf))
1820 var = Perl_malloc(l + 1);
1821 Copy(a, var, l, char);
1823 my_setenv(var, val+1);
1831 Perl_malloced_size(void *p)
1833 union overhead *ovp = (union overhead *)
1834 ((caddr_t)p - sizeof (union overhead) * CHUNK_SHIFT);
1835 int bucket = OV_INDEX(ovp);
1837 /* The caller wants to have a complete control over the chunk,
1838 disable the memory checking inside the chunk. */
1839 if (bucket <= MAX_SHORT_BUCKET) {
1840 MEM_SIZE size = BUCKET_SIZE_REAL(bucket);
1841 ovp->ov_size = size + M_OVERHEAD - 1;
1842 *((u_int *)((caddr_t)ovp + size + M_OVERHEAD - RSLOP)) = RMAGIC;
1845 return BUCKET_SIZE_REAL(bucket);
1848 # ifdef BUCKETS_ROOT2
1849 # define MIN_EVEN_REPORT 6
1851 # define MIN_EVEN_REPORT MIN_BUCKET
1855 Perl_get_mstats(pTHX_ perl_mstats_t *buf, int buflen, int level)
1857 #ifdef DEBUGGING_MSTATS
1859 register union overhead *p;
1860 struct chunk_chain_s* nextchain;
1862 buf->topbucket = buf->topbucket_ev = buf->topbucket_odd
1863 = buf->totfree = buf->total = buf->total_chain = 0;
1865 buf->minbucket = MIN_BUCKET;
1867 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
1868 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
1872 buf->ntotal[i] = nmalloc[i];
1874 buf->totfree += j * BUCKET_SIZE_REAL(i);
1875 buf->total += nmalloc[i] * BUCKET_SIZE_REAL(i);
1877 i % 2 ? (buf->topbucket_odd = i) : (buf->topbucket_ev = i);
1881 nextchain = chunk_chain;
1883 buf->total_chain += nextchain->size;
1884 nextchain = nextchain->next;
1886 buf->total_sbrk = goodsbrk + sbrk_slack;
1888 buf->sbrk_good = sbrk_good;
1889 buf->sbrk_slack = sbrk_slack;
1890 buf->start_slack = start_slack;
1891 buf->sbrked_remains = sbrked_remains;
1894 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
1897 buf->bucket_mem_size[i] = BUCKET_SIZE(i);
1898 buf->bucket_available_size[i] = BUCKET_SIZE_REAL(i);
1901 #endif /* defined DEBUGGING_MSTATS */
1902 return 0; /* XXX unused */
1905 * mstats - print out statistics about malloc
1907 * Prints two lines of numbers, one showing the length of the free list
1908 * for each size category, the second showing the number of mallocs -
1909 * frees for each size category.
1912 Perl_dump_mstats(pTHX_ char *s)
1914 #ifdef DEBUGGING_MSTATS
1916 register union overhead *p;
1917 perl_mstats_t buffer;
1918 unsigned long nf[NBUCKETS];
1919 unsigned long nt[NBUCKETS];
1920 struct chunk_chain_s* nextchain;
1924 get_mstats(&buffer, NBUCKETS, 0);
1927 PerlIO_printf(Perl_error_log,
1928 "Memory allocation statistics %s (buckets %ld(%ld)..%ld(%ld)\n",
1930 (long)BUCKET_SIZE_REAL(MIN_BUCKET),
1931 (long)BUCKET_SIZE(MIN_BUCKET),
1932 (long)BUCKET_SIZE_REAL(buffer.topbucket),
1933 (long)BUCKET_SIZE(buffer.topbucket));
1934 PerlIO_printf(Perl_error_log, "%8ld free:", buffer.totfree);
1935 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
1936 PerlIO_printf(Perl_error_log,
1937 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
1939 : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")),
1942 #ifdef BUCKETS_ROOT2
1943 PerlIO_printf(Perl_error_log, "\n\t ");
1944 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
1945 PerlIO_printf(Perl_error_log,
1946 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
1948 : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")),
1952 PerlIO_printf(Perl_error_log, "\n%8ld used:", buffer.total - buffer.totfree);
1953 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
1954 PerlIO_printf(Perl_error_log,
1955 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
1957 : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")),
1958 buffer.ntotal[i] - buffer.nfree[i]);
1960 #ifdef BUCKETS_ROOT2
1961 PerlIO_printf(Perl_error_log, "\n\t ");
1962 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
1963 PerlIO_printf(Perl_error_log,
1964 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
1966 : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")),
1967 buffer.ntotal[i] - buffer.nfree[i]);
1970 PerlIO_printf(Perl_error_log, "\nTotal sbrk(): %ld/%ld:%ld. Odd ends: pad+heads+chain+tail: %ld+%ld+%ld+%ld.\n",
1971 buffer.total_sbrk, buffer.sbrks, buffer.sbrk_good,
1972 buffer.sbrk_slack, buffer.start_slack,
1973 buffer.total_chain, buffer.sbrked_remains);
1974 #endif /* DEBUGGING_MSTATS */
1978 #ifdef USE_PERL_SBRK
1980 # if defined(__MACHTEN_PPC__) || defined(NeXT) || defined(__NeXT__) || defined(PURIFY)
1981 # define PERL_SBRK_VIA_MALLOC
1983 * MachTen's malloc() returns a buffer aligned on a two-byte boundary.
1984 * While this is adequate, it may slow down access to longer data
1985 * types by forcing multiple memory accesses. It also causes
1986 * complaints when RCHECK is in force. So we allocate six bytes
1987 * more than we need to, and return an address rounded up to an
1988 * eight-byte boundary.
1990 * 980701 Dominic Dunlop <domo@computer.org>
1992 # define SYSTEM_ALLOC_ALIGNMENT 2
1995 # ifdef PERL_SBRK_VIA_MALLOC
1997 /* it may seem schizophrenic to use perl's malloc and let it call system */
1998 /* malloc, the reason for that is only the 3.2 version of the OS that had */
1999 /* frequent core dumps within nxzonefreenolock. This sbrk routine put an */
2000 /* end to the cores */
2002 # ifndef SYSTEM_ALLOC
2003 # define SYSTEM_ALLOC(a) malloc(a)
2005 # ifndef SYSTEM_ALLOC_ALIGNMENT
2006 # define SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES
2009 # endif /* PERL_SBRK_VIA_MALLOC */
2011 static IV Perl_sbrk_oldchunk;
2012 static long Perl_sbrk_oldsize;
2014 # define PERLSBRK_32_K (1<<15)
2015 # define PERLSBRK_64_K (1<<16)
2023 if (!size) return 0;
2025 reqsize = size; /* just for the DEBUG_m statement */
2028 size = (size + 0x7ff) & ~0x7ff;
2030 if (size <= Perl_sbrk_oldsize) {
2031 got = Perl_sbrk_oldchunk;
2032 Perl_sbrk_oldchunk += size;
2033 Perl_sbrk_oldsize -= size;
2035 if (size >= PERLSBRK_32_K) {
2038 size = PERLSBRK_64_K;
2041 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2042 size += NEEDED_ALIGNMENT - SYSTEM_ALLOC_ALIGNMENT;
2044 got = (IV)SYSTEM_ALLOC(size);
2045 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2046 got = (got + NEEDED_ALIGNMENT - 1) & ~(NEEDED_ALIGNMENT - 1);
2049 /* Chunk is small, register the rest for future allocs. */
2050 Perl_sbrk_oldchunk = got + reqsize;
2051 Perl_sbrk_oldsize = size - reqsize;
2055 DEBUG_m(PerlIO_printf(Perl_debug_log, "sbrk malloc size %ld (reqsize %ld), left size %ld, give addr 0x%"UVxf"\n",
2056 size, reqsize, Perl_sbrk_oldsize, PTR2UV(got)));
2061 #endif /* ! defined USE_PERL_SBRK */