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
128 # Maximal value in LONG
131 # Unsigned integer type big enough to keep a pointer
134 # Type of pointer with 1-byte granularity
137 # Type returned by free()
140 # Very fatal condition reporting function (cannot call any )
141 fatalcroak(arg) write(2,arg,strlen(arg)) + exit(2)
143 # Fatal error reporting function
144 croak(format, arg) warn(idem) + exit(1)
146 # Error reporting function
147 warn(format, arg) fprintf(stderr, idem)
149 # Locking/unlocking for MT operation
150 MALLOC_LOCK MUTEX_LOCK_NOCONTEXT(&PL_malloc_mutex)
151 MALLOC_UNLOCK MUTEX_UNLOCK_NOCONTEXT(&PL_malloc_mutex)
153 # Locking/unlocking mutex for MT operation
158 #ifndef NO_FANCY_MALLOC
159 # ifndef SMALL_BUCKET_VIA_TABLE
160 # define SMALL_BUCKET_VIA_TABLE
162 # ifndef BUCKETS_ROOT2
163 # define BUCKETS_ROOT2
165 # ifndef IGNORE_SMALL_BAD_FREE
166 # define IGNORE_SMALL_BAD_FREE
170 #ifndef PLAIN_MALLOC /* Bulk enable features */
174 # ifndef TWO_POT_OPTIMIZE
175 # define TWO_POT_OPTIMIZE
177 # if defined(PERL_CORE) && !defined(PERL_EMERGENCY_SBRK)
178 # define PERL_EMERGENCY_SBRK
180 # if defined(PERL_CORE) && !defined(DEBUGGING_MSTATS)
181 # define DEBUGGING_MSTATS
185 #define MIN_BUC_POW2 (sizeof(void*) > 4 ? 3 : 2) /* Allow for 4-byte arena. */
186 #define MIN_BUCKET (MIN_BUC_POW2 * BUCKETS_PER_POW2)
188 #if !(defined(I286) || defined(atarist) || defined(__MINT__))
189 /* take 2k unless the block is bigger than that */
190 # define LOG_OF_MIN_ARENA 11
192 /* take 16k unless the block is bigger than that
193 (80286s like large segments!), probably good on the atari too */
194 # define LOG_OF_MIN_ARENA 14
198 # if defined(DEBUGGING) && !defined(NO_RCHECK)
201 # if defined(RCHECK) && defined(IGNORE_SMALL_BAD_FREE)
202 # undef IGNORE_SMALL_BAD_FREE
205 * malloc.c (Caltech) 2/21/82
206 * Chris Kingsley, kingsley@cit-20.
208 * This is a very fast storage allocator. It allocates blocks of a small
209 * number of different sizes, and keeps free lists of each size. Blocks that
210 * don't exactly fit are passed up to the next larger size. In this
211 * implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long.
212 * If PACK_MALLOC is defined, small blocks are 2^n bytes long.
213 * This is designed for use in a program that uses vast quantities of memory,
214 * but bombs when it runs out.
216 * Modifications Copyright Ilya Zakharevich 1996-99.
218 * Still very quick, but much more thrifty. (Std config is 10% slower
219 * than it was, and takes 67% of old heap size for typical usage.)
221 * Allocations of small blocks are now table-driven to many different
222 * buckets. Sizes of really big buckets are increased to accomodata
223 * common size=power-of-2 blocks. Running-out-of-memory is made into
224 * an exception. Deeply configurable and thread-safe.
230 # define PERL_IN_MALLOC_C
232 # if defined(PERL_IMPLICIT_CONTEXT)
233 # define croak Perl_croak_nocontext
234 # define warn Perl_warn_nocontext
238 # include "../EXTERN.h"
239 # include "../perl.h"
246 # define Malloc_t void *
249 # define MEM_SIZE unsigned long
252 # define LONG_MAX 0x7FFFFFFF
255 # define UV unsigned long
258 # define caddr_t char *
263 # define Copy(s,d,n,t) (void)memcpy((char*)(d),(char*)(s), (n) * sizeof(t))
264 # define PerlEnv_getenv getenv
265 # define PerlIO_printf fprintf
266 # define PerlIO_stderr() stderr
268 # ifndef croak /* make depend */
269 # define croak(mess, arg) (warn((mess), (arg)), exit(1))
272 # define warn(mess, arg) fprintf(stderr, (mess), (arg))
284 # define dTHX extern int Perl___notused
285 # define WITH_THX(s) s
287 # ifndef PERL_GET_INTERP
288 # define PERL_GET_INTERP PL_curinterp
291 # define Perl_malloc malloc
294 # define Perl_mfree free
296 # ifndef Perl_realloc
297 # define Perl_realloc realloc
300 # define Perl_calloc calloc
303 # define Perl_strdup strdup
308 # define MUTEX_LOCK(l)
312 # define MUTEX_UNLOCK(l)
316 # define MALLOC_LOCK MUTEX_LOCK_NOCONTEXT(&PL_malloc_mutex)
319 #ifndef MALLOC_UNLOCK
320 # define MALLOC_UNLOCK MUTEX_UNLOCK_NOCONTEXT(&PL_malloc_mutex)
323 # ifndef fatalcroak /* make depend */
324 # define fatalcroak(mess) (write(2, (mess), strlen(mess)), exit(2))
329 # define DEBUG_m(a) \
331 if (PERL_GET_INTERP) { dTHX; if (PL_debug & 128) { a; } } \
335 #ifdef PERL_IMPLICIT_CONTEXT
336 # define PERL_IS_ALIVE aTHX
338 # define PERL_IS_ALIVE TRUE
345 * The memory is broken into "blocks" which occupy multiples of 2K (and
346 * generally speaking, have size "close" to a power of 2). The addresses
347 * of such *unused* blocks are kept in nextf[i] with big enough i. (nextf
348 * is an array of linked lists.) (Addresses of used blocks are not known.)
350 * Moreover, since the algorithm may try to "bite" smaller blocks out
351 * of unused bigger ones, there are also regions of "irregular" size,
352 * managed separately, by a linked list chunk_chain.
354 * The third type of storage is the sbrk()ed-but-not-yet-used space, its
355 * end and size are kept in last_sbrk_top and sbrked_remains.
357 * Growing blocks "in place":
358 * ~~~~~~~~~~~~~~~~~~~~~~~~~
359 * The address of the block with the greatest address is kept in last_op
360 * (if not known, last_op is 0). If it is known that the memory above
361 * last_op is not continuous, or contains a chunk from chunk_chain,
362 * last_op is set to 0.
364 * The chunk with address last_op may be grown by expanding into
365 * sbrk()ed-but-not-yet-used space, or trying to sbrk() more continuous
368 * Management of last_op:
369 * ~~~~~~~~~~~~~~~~~~~~~
371 * free() never changes the boundaries of blocks, so is not relevant.
373 * The only way realloc() may change the boundaries of blocks is if it
374 * grows a block "in place". However, in the case of success such a
375 * chunk is automatically last_op, and it remains last_op. In the case
376 * of failure getpages_adjacent() clears last_op.
378 * malloc() may change blocks by calling morecore() only.
380 * morecore() may create new blocks by:
381 * a) biting pieces from chunk_chain (cannot create one above last_op);
382 * b) biting a piece from an unused block (if block was last_op, this
383 * may create a chunk from chain above last_op, thus last_op is
384 * invalidated in such a case).
385 * c) biting of sbrk()ed-but-not-yet-used space. This creates
386 * a block which is last_op.
387 * d) Allocating new pages by calling getpages();
389 * getpages() creates a new block. It marks last_op at the bottom of
390 * the chunk of memory it returns.
392 * Active pages footprint:
393 * ~~~~~~~~~~~~~~~~~~~~~~
394 * Note that we do not need to traverse the lists in nextf[i], just take
395 * the first element of this list. However, we *need* to traverse the
396 * list in chunk_chain, but most the time it should be a very short one,
397 * so we do not step on a lot of pages we are not going to use.
401 * get_from_bigger_buckets(): forget to increment price => Quite
405 /* I don't much care whether these are defined in sys/types.h--LAW */
407 #define u_char unsigned char
408 #define u_int unsigned int
410 * I removed the definition of u_bigint which appeared to be u_bigint = UV
411 * u_bigint was only used in TWOK_MASKED and TWOK_SHIFT
412 * where I have used PTR2UV. RMB
414 #define u_short unsigned short
416 /* 286 and atarist like big chunks, which gives too much overhead. */
417 #if (defined(RCHECK) || defined(I286) || defined(atarist) || defined(__MINT__)) && defined(PACK_MALLOC)
422 * The description below is applicable if PACK_MALLOC is not defined.
424 * The overhead on a block is at least 4 bytes. When free, this space
425 * contains a pointer to the next free block, and the bottom two bits must
426 * be zero. When in use, the first byte is set to MAGIC, and the second
427 * byte is the size index. The remaining bytes are for alignment.
428 * If range checking is enabled and the size of the block fits
429 * in two bytes, then the top two bytes hold the size of the requested block
430 * plus the range checking words, and the header word MINUS ONE.
433 union overhead *ov_next; /* when free */
434 #if MEM_ALIGNBYTES > 4
435 double strut; /* alignment problems */
438 u_char ovu_magic; /* magic number */
439 u_char ovu_index; /* bucket # */
441 u_short ovu_size; /* actual block size */
442 u_int ovu_rmagic; /* range magic number */
445 #define ov_magic ovu.ovu_magic
446 #define ov_index ovu.ovu_index
447 #define ov_size ovu.ovu_size
448 #define ov_rmagic ovu.ovu_rmagic
451 #define MAGIC 0xff /* magic # on accounting info */
452 #define RMAGIC 0x55555555 /* magic # on range info */
453 #define RMAGIC_C 0x55 /* magic # on range info */
456 # define RSLOP sizeof (u_int)
457 # ifdef TWO_POT_OPTIMIZE
458 # define MAX_SHORT_BUCKET (12 * BUCKETS_PER_POW2)
460 # define MAX_SHORT_BUCKET (13 * BUCKETS_PER_POW2)
466 #if !defined(PACK_MALLOC) && defined(BUCKETS_ROOT2)
467 # undef BUCKETS_ROOT2
471 # define BUCKET_TABLE_SHIFT 2
472 # define BUCKET_POW2_SHIFT 1
473 # define BUCKETS_PER_POW2 2
475 # define BUCKET_TABLE_SHIFT MIN_BUC_POW2
476 # define BUCKET_POW2_SHIFT 0
477 # define BUCKETS_PER_POW2 1
480 #if !defined(MEM_ALIGNBYTES) || ((MEM_ALIGNBYTES > 4) && !defined(STRICT_ALIGNMENT))
481 /* Figure out the alignment of void*. */
486 # define ALIGN_SMALL ((int)((caddr_t)&(((struct aligner*)0)->p)))
488 # define ALIGN_SMALL MEM_ALIGNBYTES
491 #define IF_ALIGN_8(yes,no) ((ALIGN_SMALL>4) ? (yes) : (no))
494 # define MAX_BUCKET_BY_TABLE 13
495 static u_short buck_size[MAX_BUCKET_BY_TABLE + 1] =
497 0, 0, 0, 0, 4, 4, 8, 12, 16, 24, 32, 48, 64, 80,
499 # define BUCKET_SIZE(i) ((i) % 2 ? buck_size[i] : (1 << ((i) >> BUCKET_POW2_SHIFT)))
500 # define BUCKET_SIZE_REAL(i) ((i) <= MAX_BUCKET_BY_TABLE \
502 : ((1 << ((i) >> BUCKET_POW2_SHIFT)) \
504 + POW2_OPTIMIZE_SURPLUS(i)))
506 # define BUCKET_SIZE(i) (1 << ((i) >> BUCKET_POW2_SHIFT))
507 # define BUCKET_SIZE_REAL(i) (BUCKET_SIZE(i) - MEM_OVERHEAD(i) + POW2_OPTIMIZE_SURPLUS(i))
512 /* In this case there are several possible layout of arenas depending
513 * on the size. Arenas are of sizes multiple to 2K, 2K-aligned, and
514 * have a size close to a power of 2.
516 * Arenas of the size >= 4K keep one chunk only. Arenas of size 2K
517 * may keep one chunk or multiple chunks. Here are the possible
520 * # One chunk only, chunksize 2^k + SOMETHING - ALIGN, k >= 11
522 * INDEX MAGIC1 UNUSED CHUNK1
524 * # Multichunk with sanity checking and chunksize 2^k-ALIGN, k>7
526 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 CHUNK2 CHUNK3 ...
528 * # Multichunk with sanity checking and size 2^k-ALIGN, k=7
530 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 UNUSED CHUNK2 CHUNK3 ...
532 * # Multichunk with sanity checking and size up to 80
534 * INDEX UNUSED MAGIC1 UNUSED MAGIC2 UNUSED ... CHUNK1 CHUNK2 CHUNK3 ...
536 * # No sanity check (usually up to 48=byte-long buckets)
537 * INDEX UNUSED CHUNK1 CHUNK2 ...
539 * Above INDEX and MAGIC are one-byte-long. Sizes of UNUSED are
540 * appropriate to keep algorithms simple and memory aligned. INDEX
541 * encodes the size of the chunk, while MAGICn encodes state (used,
542 * free or non-managed-by-us-so-it-indicates-a-bug) of CHUNKn. MAGIC
543 * is used for sanity checking purposes only. SOMETHING is 0 or 4K
544 * (to make size of big CHUNK accomodate allocations for powers of two
547 * [There is no need to alignment between chunks, since C rules ensure
548 * that structs which need 2^k alignment have sizeof which is
549 * divisible by 2^k. Thus as far as the last chunk is aligned at the
550 * end of the arena, and 2K-alignment does not contradict things,
551 * everything is going to be OK for sizes of chunks 2^n and 2^n +
552 * 2^k. Say, 80-bit buckets will be 16-bit aligned, and as far as we
553 * put allocations for requests in 65..80 range, all is fine.
555 * Note, however, that standard malloc() puts more strict
556 * requirements than the above C rules. Moreover, our algorithms of
557 * realloc() may break this idyll, but we suppose that realloc() does
558 * need not change alignment.]
560 * Is very important to make calculation of the offset of MAGICm as
561 * quick as possible, since it is done on each malloc()/free(). In
562 * fact it is so quick that it has quite little effect on the speed of
563 * doing malloc()/free(). [By default] We forego such calculations
564 * for small chunks, but only to save extra 3% of memory, not because
565 * of speed considerations.
567 * Here is the algorithm [which is the same for all the allocations
568 * schemes above], see OV_MAGIC(block,bucket). Let OFFSETm be the
569 * offset of the CHUNKm from the start of ARENA. Then offset of
570 * MAGICm is (OFFSET1 >> SHIFT) + ADDOFFSET. Here SHIFT and ADDOFFSET
571 * are numbers which depend on the size of the chunks only.
573 * Let as check some sanity conditions. Numbers OFFSETm>>SHIFT are
574 * different for all the chunks in the arena if 2^SHIFT is not greater
575 * than size of the chunks in the arena. MAGIC1 will not overwrite
576 * INDEX provided ADDOFFSET is >0 if OFFSET1 < 2^SHIFT. MAGIClast
577 * will not overwrite CHUNK1 if OFFSET1 > (OFFSETlast >> SHIFT) +
580 * Make SHIFT the maximal possible (there is no point in making it
581 * smaller). Since OFFSETlast is 2K - CHUNKSIZE, above restrictions
582 * give restrictions on OFFSET1 and on ADDOFFSET.
584 * In particular, for chunks of size 2^k with k>=6 we can put
585 * ADDOFFSET to be from 0 to 2^k - 2^(11-k), and have
586 * OFFSET1==chunksize. For chunks of size 80 OFFSET1 of 2K%80=48 is
587 * large enough to have ADDOFFSET between 1 and 16 (similarly for 96,
588 * when ADDOFFSET should be 1). In particular, keeping MAGICs for
589 * these sizes gives no additional size penalty.
591 * However, for chunks of size 2^k with k<=5 this gives OFFSET1 >=
592 * ADDOFSET + 2^(11-k). Keeping ADDOFFSET 0 allows for 2^(11-k)-2^(11-2k)
593 * chunks per arena. This is smaller than 2^(11-k) - 1 which are
594 * needed if no MAGIC is kept. [In fact, having a negative ADDOFFSET
595 * would allow for slightly more buckets per arena for k=2,3.]
597 * Similarly, for chunks of size 3/2*2^k with k<=5 MAGICs would span
598 * the area up to 2^(11-k)+ADDOFFSET. For k=4 this give optimal
599 * ADDOFFSET as -7..0. For k=3 ADDOFFSET can go up to 4 (with tiny
600 * savings for negative ADDOFFSET). For k=5 ADDOFFSET can go -1..16
601 * (with no savings for negative values).
603 * In particular, keeping ADDOFFSET 0 for sizes of chunks up to 2^6
604 * leads to tiny pessimizations in case of sizes 4, 8, 12, 24, and
605 * leads to no contradictions except for size=80 (or 96.)
607 * However, it also makes sense to keep no magic for sizes 48 or less.
608 * This is what we do. In this case one needs ADDOFFSET>=1 also for
609 * chunksizes 12, 24, and 48, unless one gets one less chunk per
612 * The algo of OV_MAGIC(block,bucket) keeps ADDOFFSET 0 until
613 * chunksize of 64, then makes it 1.
615 * This allows for an additional optimization: the above scheme leads
616 * to giant overheads for sizes 128 or more (one whole chunk needs to
617 * be sacrifised to keep INDEX). Instead we use chunks not of size
618 * 2^k, but of size 2^k-ALIGN. If we pack these chunks at the end of
619 * the arena, then the beginnings are still in different 2^k-long
620 * sections of the arena if k>=7 for ALIGN==4, and k>=8 if ALIGN=8.
621 * Thus for k>7 the above algo of calculating the offset of the magic
622 * will still give different answers for different chunks. And to
623 * avoid the overrun of MAGIC1 into INDEX, one needs ADDOFFSET of >=1.
624 * In the case k=7 we just move the first chunk an extra ALIGN
625 * backward inside the ARENA (this is done once per arena lifetime,
626 * thus is not a big overhead). */
627 # define MAX_PACKED_POW2 6
628 # define MAX_PACKED (MAX_PACKED_POW2 * BUCKETS_PER_POW2 + BUCKET_POW2_SHIFT)
629 # define MAX_POW2_ALGO ((1<<(MAX_PACKED_POW2 + 1)) - M_OVERHEAD)
630 # define TWOK_MASK ((1<<LOG_OF_MIN_ARENA) - 1)
631 # define TWOK_MASKED(x) (PTR2UV(x) & ~TWOK_MASK)
632 # define TWOK_SHIFT(x) (PTR2UV(x) & TWOK_MASK)
633 # define OV_INDEXp(block) (INT2PTR(u_char*,TWOK_MASKED(block)))
634 # define OV_INDEX(block) (*OV_INDEXp(block))
635 # define OV_MAGIC(block,bucket) (*(OV_INDEXp(block) + \
636 (TWOK_SHIFT(block)>> \
637 (bucket>>BUCKET_POW2_SHIFT)) + \
638 (bucket >= MIN_NEEDS_SHIFT ? 1 : 0)))
639 /* A bucket can have a shift smaller than it size, we need to
640 shift its magic number so it will not overwrite index: */
641 # ifdef BUCKETS_ROOT2
642 # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2 - 1) /* Shift 80 greater than chunk 64. */
644 # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2) /* Shift 128 greater than chunk 32. */
646 # define CHUNK_SHIFT 0
648 /* Number of active buckets of given ordinal. */
649 #ifdef IGNORE_SMALL_BAD_FREE
650 #define FIRST_BUCKET_WITH_CHECK (6 * BUCKETS_PER_POW2) /* 64 */
651 # define N_BLKS(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \
652 ? ((1<<LOG_OF_MIN_ARENA) - 1)/BUCKET_SIZE(bucket) \
655 # define N_BLKS(bucket) n_blks[bucket]
658 static u_short n_blks[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
660 # if BUCKETS_PER_POW2==1
662 (MIN_BUC_POW2==2 ? 384 : 0),
663 224, 120, 62, 31, 16, 8, 4, 2
666 (MIN_BUC_POW2==2 ? 384 : 0), (MIN_BUC_POW2==2 ? 384 : 0), /* 4, 4 */
667 224, 149, 120, 80, 62, 41, 31, 25, 16, 16, 8, 8, 4, 4, 2, 2
671 /* Shift of the first bucket with the given ordinal inside 2K chunk. */
672 #ifdef IGNORE_SMALL_BAD_FREE
673 # define BLK_SHIFT(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \
674 ? ((1<<LOG_OF_MIN_ARENA) \
675 - BUCKET_SIZE(bucket) * N_BLKS(bucket)) \
678 # define BLK_SHIFT(bucket) blk_shift[bucket]
681 static u_short blk_shift[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
683 # if BUCKETS_PER_POW2==1
685 (MIN_BUC_POW2==2 ? 512 : 0),
686 256, 128, 64, 64, /* 8 to 64 */
687 16*sizeof(union overhead),
688 8*sizeof(union overhead),
689 4*sizeof(union overhead),
690 2*sizeof(union overhead),
693 (MIN_BUC_POW2==2 ? 512 : 0), (MIN_BUC_POW2==2 ? 512 : 0),
694 256, 260, 128, 128, 64, 80, 64, 48, /* 8 to 96 */
695 16*sizeof(union overhead), 16*sizeof(union overhead),
696 8*sizeof(union overhead), 8*sizeof(union overhead),
697 4*sizeof(union overhead), 4*sizeof(union overhead),
698 2*sizeof(union overhead), 2*sizeof(union overhead),
702 # define NEEDED_ALIGNMENT 0x800 /* 2k boundaries */
703 # define WANTED_ALIGNMENT 0x800 /* 2k boundaries */
705 #else /* !PACK_MALLOC */
707 # define OV_MAGIC(block,bucket) (block)->ov_magic
708 # define OV_INDEX(block) (block)->ov_index
709 # define CHUNK_SHIFT 1
710 # define MAX_PACKED -1
711 # define NEEDED_ALIGNMENT MEM_ALIGNBYTES
712 # define WANTED_ALIGNMENT 0x400 /* 1k boundaries */
714 #endif /* !PACK_MALLOC */
716 #define M_OVERHEAD (sizeof(union overhead) + RSLOP)
719 # define MEM_OVERHEAD(bucket) \
720 (bucket <= MAX_PACKED ? 0 : M_OVERHEAD)
721 # ifdef SMALL_BUCKET_VIA_TABLE
722 # define START_SHIFTS_BUCKET ((MAX_PACKED_POW2 + 1) * BUCKETS_PER_POW2)
723 # define START_SHIFT MAX_PACKED_POW2
724 # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */
725 # define SIZE_TABLE_MAX 80
727 # define SIZE_TABLE_MAX 64
729 static char bucket_of[] =
731 # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */
732 /* 0 to 15 in 4-byte increments. */
733 (sizeof(void*) > 4 ? 6 : 5), /* 4/8, 5-th bucket for better reports */
735 IF_ALIGN_8(8,7), 8, /* 16/12, 16 */
736 9, 9, 10, 10, /* 24, 32 */
737 11, 11, 11, 11, /* 48 */
738 12, 12, 12, 12, /* 64 */
739 13, 13, 13, 13, /* 80 */
740 13, 13, 13, 13 /* 80 */
741 # else /* !BUCKETS_ROOT2 */
742 /* 0 to 15 in 4-byte increments. */
743 (sizeof(void*) > 4 ? 3 : 2),
749 # endif /* !BUCKETS_ROOT2 */
751 # else /* !SMALL_BUCKET_VIA_TABLE */
752 # define START_SHIFTS_BUCKET MIN_BUCKET
753 # define START_SHIFT (MIN_BUC_POW2 - 1)
754 # endif /* !SMALL_BUCKET_VIA_TABLE */
755 #else /* !PACK_MALLOC */
756 # define MEM_OVERHEAD(bucket) M_OVERHEAD
757 # ifdef SMALL_BUCKET_VIA_TABLE
758 # undef SMALL_BUCKET_VIA_TABLE
760 # define START_SHIFTS_BUCKET MIN_BUCKET
761 # define START_SHIFT (MIN_BUC_POW2 - 1)
762 #endif /* !PACK_MALLOC */
765 * Big allocations are often of the size 2^n bytes. To make them a
766 * little bit better, make blocks of size 2^n+pagesize for big n.
769 #ifdef TWO_POT_OPTIMIZE
771 # ifndef PERL_PAGESIZE
772 # define PERL_PAGESIZE 4096
774 # ifndef FIRST_BIG_POW2
775 # define FIRST_BIG_POW2 15 /* 32K, 16K is used too often. */
777 # define FIRST_BIG_BLOCK (1<<FIRST_BIG_POW2)
778 /* If this value or more, check against bigger blocks. */
779 # define FIRST_BIG_BOUND (FIRST_BIG_BLOCK - M_OVERHEAD)
780 /* If less than this value, goes into 2^n-overhead-block. */
781 # define LAST_SMALL_BOUND ((FIRST_BIG_BLOCK>>1) - M_OVERHEAD)
783 # define POW2_OPTIMIZE_ADJUST(nbytes) \
784 ((nbytes >= FIRST_BIG_BOUND) ? nbytes -= PERL_PAGESIZE : 0)
785 # define POW2_OPTIMIZE_SURPLUS(bucket) \
786 ((bucket >= FIRST_BIG_POW2 * BUCKETS_PER_POW2) ? PERL_PAGESIZE : 0)
788 #else /* !TWO_POT_OPTIMIZE */
789 # define POW2_OPTIMIZE_ADJUST(nbytes)
790 # define POW2_OPTIMIZE_SURPLUS(bucket) 0
791 #endif /* !TWO_POT_OPTIMIZE */
793 #if defined(HAS_64K_LIMIT) && defined(PERL_CORE)
794 # define BARK_64K_LIMIT(what,nbytes,size) \
795 if (nbytes > 0xffff) { \
796 PerlIO_printf(PerlIO_stderr(), \
797 "%s too large: %lx\n", what, size); \
800 #else /* !HAS_64K_LIMIT || !PERL_CORE */
801 # define BARK_64K_LIMIT(what,nbytes,size)
802 #endif /* !HAS_64K_LIMIT || !PERL_CORE */
805 # define MIN_SBRK 2048
809 # define FIRST_SBRK (48*1024)
812 /* Minimal sbrk in percents of what is already alloced. */
813 #ifndef MIN_SBRK_FRAC
814 # define MIN_SBRK_FRAC 3
817 #ifndef SBRK_ALLOW_FAILURES
818 # define SBRK_ALLOW_FAILURES 3
821 #ifndef SBRK_FAILURE_PRICE
822 # define SBRK_FAILURE_PRICE 50
825 #if defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)
828 # define BIG_SIZE (1<<16) /* 64K */
831 #ifdef I_MACH_CTHREADS
833 # define MUTEX_LOCK(m) STMT_START { if (*m) mutex_lock(*m); } STMT_END
835 # define MUTEX_UNLOCK(m) STMT_START { if (*m) mutex_unlock(*m); } STMT_END
838 static char *emergency_buffer;
839 static MEM_SIZE emergency_buffer_size;
841 static int findbucket (union overhead *freep, int srchlen);
842 static void morecore (register int bucket);
843 # if defined(DEBUGGING)
844 static void botch (char *diag, char *s);
846 static void add_to_chain (void *p, MEM_SIZE size, MEM_SIZE chip);
847 static Malloc_t emergency_sbrk (MEM_SIZE size);
848 static void* get_from_chain (MEM_SIZE size);
849 static void* get_from_bigger_buckets(int bucket, MEM_SIZE size);
850 static union overhead *getpages (int needed, int *nblksp, int bucket);
851 static int getpages_adjacent(int require);
854 emergency_sbrk(MEM_SIZE size)
856 MEM_SIZE rsize = (((size - 1)>>LOG_OF_MIN_ARENA) + 1)<<LOG_OF_MIN_ARENA;
858 if (size >= BIG_SIZE) {
859 /* Give the possibility to recover: */
861 croak("Out of memory during \"large\" request for %i bytes", size);
864 if (emergency_buffer_size >= rsize) {
865 char *old = emergency_buffer;
867 emergency_buffer_size -= rsize;
868 emergency_buffer += rsize;
872 /* First offense, give a possibility to recover by dieing. */
873 /* No malloc involved here: */
874 GV **gvp = (GV**)hv_fetch(PL_defstash, "^M", 2, 0);
880 if (emergency_buffer_size) {
881 add_to_chain(emergency_buffer, emergency_buffer_size, 0);
882 emergency_buffer_size = 0;
883 emergency_buffer = Nullch;
886 if (!gvp) gvp = (GV**)hv_fetch(PL_defstash, "\015", 1, 0);
887 if (!gvp || !(sv = GvSV(*gvp)) || !SvPOK(sv)
888 || (SvLEN(sv) < (1<<LOG_OF_MIN_ARENA) - M_OVERHEAD)) {
891 return (char *)-1; /* Now die die die... */
893 /* Got it, now detach SvPV: */
895 /* Check alignment: */
896 if ((PTR2UV(pv) - sizeof(union overhead)) & (NEEDED_ALIGNMENT - 1)) {
897 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
898 return (char *)-1; /* die die die */
901 emergency_buffer = pv - sizeof(union overhead);
902 emergency_buffer_size = malloced_size(pv) + M_OVERHEAD;
905 SvCUR(sv) = SvLEN(sv) = 0;
909 croak("Out of memory during request for %i bytes", size);
914 #else /* !(defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)) */
915 # define emergency_sbrk(size) -1
916 #endif /* !(defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)) */
919 * nextf[i] is the pointer to the next free block of size 2^i. The
920 * smallest allocatable block is 8 bytes. The overhead information
921 * precedes the data area returned to the user.
923 #define NBUCKETS (32*BUCKETS_PER_POW2 + 1)
924 static union overhead *nextf[NBUCKETS];
926 #if defined(PURIFY) && !defined(USE_PERL_SBRK)
927 # define USE_PERL_SBRK
931 #define sbrk(a) Perl_sbrk(a)
932 Malloc_t Perl_sbrk (int size);
934 #ifdef DONT_DECLARE_STD
939 extern Malloc_t sbrk(int);
943 #ifdef DEBUGGING_MSTATS
945 * nmalloc[i] is the difference between the number of mallocs and frees
946 * for a given block size.
948 static u_int nmalloc[NBUCKETS];
949 static u_int sbrk_slack;
950 static u_int start_slack;
953 static u_int goodsbrk;
957 #define ASSERT(p,diag) if (!(p)) botch(diag,STRINGIFY(p)); else
959 botch(char *diag, char *s)
962 PerlIO_printf(PerlIO_stderr(), "assertion botched (%s?): %s\n", diag, s);
966 #define ASSERT(p, diag)
970 Perl_malloc(register size_t nbytes)
972 register union overhead *p;
974 register MEM_SIZE shiftr;
976 #if defined(DEBUGGING) || defined(RCHECK)
977 MEM_SIZE size = nbytes;
980 BARK_64K_LIMIT("Allocation",nbytes,nbytes);
982 if ((long)nbytes < 0)
983 croak("%s", "panic: malloc");
987 * Convert amount of memory requested into
988 * closest block size stored in hash buckets
989 * which satisfies request. Account for
990 * space used per block for accounting.
993 # ifdef SMALL_BUCKET_VIA_TABLE
996 else if (nbytes <= SIZE_TABLE_MAX) {
997 bucket = bucket_of[(nbytes - 1) >> BUCKET_TABLE_SHIFT];
1002 if (nbytes <= MAX_POW2_ALGO) goto do_shifts;
1007 POW2_OPTIMIZE_ADJUST(nbytes);
1008 nbytes += M_OVERHEAD;
1009 nbytes = (nbytes + 3) &~ 3;
1011 shiftr = (nbytes - 1) >> START_SHIFT;
1012 bucket = START_SHIFTS_BUCKET;
1013 /* apart from this loop, this is O(1) */
1014 while (shiftr >>= 1)
1015 bucket += BUCKETS_PER_POW2;
1019 * If nothing in hash bucket right now,
1020 * request more memory from the system.
1022 if (nextf[bucket] == NULL)
1024 if ((p = nextf[bucket]) == NULL) {
1030 PerlIO_puts(PerlIO_stderr(),"Out of memory!\n");
1038 DEBUG_m(PerlIO_printf(Perl_debug_log,
1039 "0x%"UVxf": (%05lu) malloc %ld bytes\n",
1040 PTR2UV(p+1), (unsigned long)(PL_an++),
1043 /* remove from linked list */
1045 if ((PTR2UV(p)) & (MEM_ALIGNBYTES - 1)) {
1047 PerlIO_printf(PerlIO_stderr(),
1048 "Unaligned pointer in the free chain 0x%"UVxf"\n",
1051 if ((PTR2UV(p->ov_next)) & (MEM_ALIGNBYTES - 1)) {
1053 PerlIO_printf(PerlIO_stderr(),
1054 "Unaligned `next' pointer in the free "
1055 "chain 0x"UVxf" at 0x%"UVxf"\n",
1056 PTR2UV(p->ov_next), PTR2UV(p));
1059 nextf[bucket] = p->ov_next;
1063 #ifdef IGNORE_SMALL_BAD_FREE
1064 if (bucket >= FIRST_BUCKET_WITH_CHECK)
1066 OV_MAGIC(p, bucket) = MAGIC;
1068 OV_INDEX(p) = bucket;
1072 * Record allocated size of block and
1073 * bound space with magic numbers.
1075 p->ov_rmagic = RMAGIC;
1076 if (bucket <= MAX_SHORT_BUCKET) {
1079 nbytes = size + M_OVERHEAD;
1080 p->ov_size = nbytes - 1;
1081 if ((i = nbytes & 3)) {
1084 *((char *)((caddr_t)p + nbytes - RSLOP + i)) = RMAGIC_C;
1086 nbytes = (nbytes + 3) &~ 3;
1087 *((u_int *)((caddr_t)p + nbytes - RSLOP)) = RMAGIC;
1090 return ((Malloc_t)(p + CHUNK_SHIFT));
1093 static char *last_sbrk_top;
1094 static char *last_op; /* This arena can be easily extended. */
1095 static int sbrked_remains;
1096 static int sbrk_good = SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE;
1098 #ifdef DEBUGGING_MSTATS
1102 struct chunk_chain_s {
1103 struct chunk_chain_s *next;
1106 static struct chunk_chain_s *chunk_chain;
1107 static int n_chunks;
1108 static char max_bucket;
1110 /* Cutoff a piece of one of the chunks in the chain. Prefer smaller chunk. */
1112 get_from_chain(MEM_SIZE size)
1114 struct chunk_chain_s *elt = chunk_chain, **oldp = &chunk_chain;
1115 struct chunk_chain_s **oldgoodp = NULL;
1116 long min_remain = LONG_MAX;
1119 if (elt->size >= size) {
1120 long remains = elt->size - size;
1121 if (remains >= 0 && remains < min_remain) {
1123 min_remain = remains;
1129 oldp = &( elt->next );
1132 if (!oldgoodp) return NULL;
1134 void *ret = *oldgoodp;
1135 struct chunk_chain_s *next = (*oldgoodp)->next;
1137 *oldgoodp = (struct chunk_chain_s *)((char*)ret + size);
1138 (*oldgoodp)->size = min_remain;
1139 (*oldgoodp)->next = next;
1142 void *ret = *oldgoodp;
1143 *oldgoodp = (*oldgoodp)->next;
1150 add_to_chain(void *p, MEM_SIZE size, MEM_SIZE chip)
1152 struct chunk_chain_s *next = chunk_chain;
1153 char *cp = (char*)p;
1156 chunk_chain = (struct chunk_chain_s *)cp;
1157 chunk_chain->size = size - chip;
1158 chunk_chain->next = next;
1163 get_from_bigger_buckets(int bucket, MEM_SIZE size)
1166 static int bucketprice[NBUCKETS];
1167 while (bucket <= max_bucket) {
1168 /* We postpone stealing from bigger buckets until we want it
1170 if (nextf[bucket] && bucketprice[bucket]++ >= price) {
1172 void *ret = (void*)(nextf[bucket] - 1 + CHUNK_SHIFT);
1173 bucketprice[bucket] = 0;
1174 if (((char*)nextf[bucket]) - M_OVERHEAD == last_op) {
1175 last_op = NULL; /* Disable optimization */
1177 nextf[bucket] = nextf[bucket]->ov_next;
1178 #ifdef DEBUGGING_MSTATS
1180 start_slack -= M_OVERHEAD;
1182 add_to_chain(ret, (BUCKET_SIZE(bucket) +
1183 POW2_OPTIMIZE_SURPLUS(bucket)),
1192 static union overhead *
1193 getpages(int needed, int *nblksp, int bucket)
1195 /* Need to do (possibly expensive) system call. Try to
1196 optimize it for rare calling. */
1197 MEM_SIZE require = needed - sbrked_remains;
1199 union overhead *ovp;
1202 if (sbrk_good > 0) {
1203 if (!last_sbrk_top && require < FIRST_SBRK)
1204 require = FIRST_SBRK;
1205 else if (require < MIN_SBRK) require = MIN_SBRK;
1207 if (require < goodsbrk * MIN_SBRK_FRAC / 100)
1208 require = goodsbrk * MIN_SBRK_FRAC / 100;
1209 require = ((require - 1 + MIN_SBRK) / MIN_SBRK) * MIN_SBRK;
1216 DEBUG_m(PerlIO_printf(Perl_debug_log,
1217 "sbrk(%ld) for %ld-byte-long arena\n",
1218 (long)require, (long) needed));
1219 cp = (char *)sbrk(require);
1220 #ifdef DEBUGGING_MSTATS
1223 if (cp == last_sbrk_top) {
1224 /* Common case, anything is fine. */
1226 ovp = (union overhead *) (cp - sbrked_remains);
1227 last_op = cp - sbrked_remains;
1228 sbrked_remains = require - (needed - sbrked_remains);
1229 } else if (cp == (char *)-1) { /* no more room! */
1230 ovp = (union overhead *)emergency_sbrk(needed);
1231 if (ovp == (union overhead *)-1)
1233 if (((char*)ovp) > last_op) { /* Cannot happen with current emergency_sbrk() */
1237 } else { /* Non-continuous or first sbrk(). */
1238 long add = sbrked_remains;
1241 if (sbrked_remains) { /* Put rest into chain, we
1242 cannot use it right now. */
1243 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1247 /* Second, check alignment. */
1250 #if !defined(atarist) && !defined(__MINT__) /* on the atari we dont have to worry about this */
1251 # ifndef I286 /* The sbrk(0) call on the I286 always returns the next segment */
1252 /* WANTED_ALIGNMENT may be more than NEEDED_ALIGNMENT, but this may
1253 improve performance of memory access. */
1254 if (PTR2UV(cp) & (WANTED_ALIGNMENT - 1)) { /* Not aligned. */
1255 slack = WANTED_ALIGNMENT - (PTR2UV(cp) & (WANTED_ALIGNMENT - 1));
1259 #endif /* !atarist && !MINT */
1262 DEBUG_m(PerlIO_printf(Perl_debug_log,
1263 "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",
1264 (long)add, (long) slack,
1265 (long) sbrked_remains));
1266 newcp = (char *)sbrk(add);
1267 #if defined(DEBUGGING_MSTATS)
1271 if (newcp != cp + require) {
1272 /* Too bad: even rounding sbrk() is not continuous.*/
1273 DEBUG_m(PerlIO_printf(Perl_debug_log,
1274 "failed to fix bad sbrk()\n"));
1278 fatalcroak("panic: Off-page sbrk\n");
1281 if (sbrked_remains) {
1283 #if defined(DEBUGGING_MSTATS)
1284 sbrk_slack += require;
1287 DEBUG_m(PerlIO_printf(Perl_debug_log,
1288 "straight sbrk(%ld)\n",
1290 cp = (char *)sbrk(require);
1291 #ifdef DEBUGGING_MSTATS
1294 if (cp == (char *)-1)
1297 sbrk_good = -1; /* Disable optimization!
1298 Continue with not-aligned... */
1301 require += sbrked_remains;
1305 if (last_sbrk_top) {
1306 sbrk_good -= SBRK_FAILURE_PRICE;
1309 ovp = (union overhead *) cp;
1311 * Round up to minimum allocation size boundary
1312 * and deduct from block count to reflect.
1315 # if NEEDED_ALIGNMENT > MEM_ALIGNBYTES
1316 if (PTR2UV(ovp) & (NEEDED_ALIGNMENT - 1))
1317 fatalcroak("Misalignment of sbrk()\n");
1320 #ifndef I286 /* Again, this should always be ok on an 80286 */
1321 if (PTR2UV(ovp) & (MEM_ALIGNBYTES - 1)) {
1322 DEBUG_m(PerlIO_printf(Perl_debug_log,
1323 "fixing sbrk(): %d bytes off machine alignement\n",
1324 (int)(PTR2UV(ovp) & (MEM_ALIGNBYTES - 1))));
1325 ovp = INT2PTR(union overhead *,(PTR2UV(ovp) + MEM_ALIGNBYTES) &
1326 (MEM_ALIGNBYTES - 1));
1328 # if defined(DEBUGGING_MSTATS)
1329 /* This is only approx. if TWO_POT_OPTIMIZE: */
1330 sbrk_slack += (1 << (bucket >> BUCKET_POW2_SHIFT));
1334 ; /* Finish `else' */
1335 sbrked_remains = require - needed;
1338 last_sbrk_top = cp + require;
1339 #ifdef DEBUGGING_MSTATS
1340 goodsbrk += require;
1346 getpages_adjacent(int require)
1348 if (require <= sbrked_remains) {
1349 sbrked_remains -= require;
1353 require -= sbrked_remains;
1354 /* We do not try to optimize sbrks here, we go for place. */
1355 cp = (char*) sbrk(require);
1356 #ifdef DEBUGGING_MSTATS
1358 goodsbrk += require;
1360 if (cp == last_sbrk_top) {
1362 last_sbrk_top = cp + require;
1364 if (cp == (char*)-1) { /* Out of memory */
1365 #ifdef DEBUGGING_MSTATS
1366 goodsbrk -= require;
1370 /* Report the failure: */
1372 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1374 add_to_chain((void*)cp, require, 0);
1375 sbrk_good -= SBRK_FAILURE_PRICE;
1387 * Allocate more memory to the indicated bucket.
1390 morecore(register int bucket)
1392 register union overhead *ovp;
1393 register int rnu; /* 2^rnu bytes will be requested */
1394 int nblks; /* become nblks blocks of the desired size */
1395 register MEM_SIZE siz, needed;
1399 if (bucket == sizeof(MEM_SIZE)*8*BUCKETS_PER_POW2) {
1401 croak("%s", "Out of memory during ridiculously large request");
1403 if (bucket > max_bucket)
1404 max_bucket = bucket;
1406 rnu = ( (bucket <= (LOG_OF_MIN_ARENA << BUCKET_POW2_SHIFT))
1408 : (bucket >> BUCKET_POW2_SHIFT) );
1409 /* This may be overwritten later: */
1410 nblks = 1 << (rnu - (bucket >> BUCKET_POW2_SHIFT)); /* how many blocks to get */
1411 needed = ((MEM_SIZE)1 << rnu) + POW2_OPTIMIZE_SURPLUS(bucket);
1412 if (nextf[rnu << BUCKET_POW2_SHIFT]) { /* 2048b bucket. */
1413 ovp = nextf[rnu << BUCKET_POW2_SHIFT] - 1 + CHUNK_SHIFT;
1414 nextf[rnu << BUCKET_POW2_SHIFT]
1415 = nextf[rnu << BUCKET_POW2_SHIFT]->ov_next;
1416 #ifdef DEBUGGING_MSTATS
1417 nmalloc[rnu << BUCKET_POW2_SHIFT]--;
1418 start_slack -= M_OVERHEAD;
1420 DEBUG_m(PerlIO_printf(Perl_debug_log,
1421 "stealing %ld bytes from %ld arena\n",
1422 (long) needed, (long) rnu << BUCKET_POW2_SHIFT));
1423 } else if (chunk_chain
1424 && (ovp = (union overhead*) get_from_chain(needed))) {
1425 DEBUG_m(PerlIO_printf(Perl_debug_log,
1426 "stealing %ld bytes from chain\n",
1428 } else if ( (ovp = (union overhead*)
1429 get_from_bigger_buckets((rnu << BUCKET_POW2_SHIFT) + 1,
1431 DEBUG_m(PerlIO_printf(Perl_debug_log,
1432 "stealing %ld bytes from bigger buckets\n",
1434 } else if (needed <= sbrked_remains) {
1435 ovp = (union overhead *)(last_sbrk_top - sbrked_remains);
1436 sbrked_remains -= needed;
1437 last_op = (char*)ovp;
1439 ovp = getpages(needed, &nblks, bucket);
1445 * Add new memory allocated to that on
1446 * free list for this hash bucket.
1448 siz = BUCKET_SIZE(bucket);
1450 *(u_char*)ovp = bucket; /* Fill index. */
1451 if (bucket <= MAX_PACKED) {
1452 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1453 nblks = N_BLKS(bucket);
1454 # ifdef DEBUGGING_MSTATS
1455 start_slack += BLK_SHIFT(bucket);
1457 } else if (bucket < LOG_OF_MIN_ARENA * BUCKETS_PER_POW2) {
1458 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1459 siz -= sizeof(union overhead);
1460 } else ovp++; /* One chunk per block. */
1461 #endif /* PACK_MALLOC */
1462 nextf[bucket] = ovp;
1463 #ifdef DEBUGGING_MSTATS
1464 nmalloc[bucket] += nblks;
1465 if (bucket > MAX_PACKED) {
1466 start_slack += M_OVERHEAD * nblks;
1469 while (--nblks > 0) {
1470 ovp->ov_next = (union overhead *)((caddr_t)ovp + siz);
1471 ovp = (union overhead *)((caddr_t)ovp + siz);
1473 /* Not all sbrks return zeroed memory.*/
1474 ovp->ov_next = (union overhead *)NULL;
1476 if (bucket == 7*BUCKETS_PER_POW2) { /* Special case, explanation is above. */
1477 union overhead *n_op = nextf[7*BUCKETS_PER_POW2]->ov_next;
1478 nextf[7*BUCKETS_PER_POW2] =
1479 (union overhead *)((caddr_t)nextf[7*BUCKETS_PER_POW2]
1480 - sizeof(union overhead));
1481 nextf[7*BUCKETS_PER_POW2]->ov_next = n_op;
1483 #endif /* !PACK_MALLOC */
1487 Perl_mfree(void *mp)
1489 register MEM_SIZE size;
1490 register union overhead *ovp;
1491 char *cp = (char*)mp;
1496 DEBUG_m(PerlIO_printf(Perl_debug_log,
1497 "0x%"UVxf": (%05lu) free\n",
1498 PTR2UV(cp), (unsigned long)(PL_an++)));
1502 ovp = (union overhead *)((caddr_t)cp
1503 - sizeof (union overhead) * CHUNK_SHIFT);
1505 bucket = OV_INDEX(ovp);
1507 #ifdef IGNORE_SMALL_BAD_FREE
1508 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
1509 && (OV_MAGIC(ovp, bucket) != MAGIC))
1511 if (OV_MAGIC(ovp, bucket) != MAGIC)
1514 static int bad_free_warn = -1;
1515 if (bad_free_warn == -1) {
1517 char *pbf = PerlEnv_getenv("PERL_BADFREE");
1518 bad_free_warn = (pbf) ? atoi(pbf) : 1;
1526 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1527 Perl_warner(aTHX_ WARN_MALLOC, "%s free() ignored",
1528 ovp->ov_rmagic == RMAGIC - 1 ?
1529 "Duplicate" : "Bad");
1532 warn("%s free() ignored",
1533 ovp->ov_rmagic == RMAGIC - 1 ? "Duplicate" : "Bad");
1539 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1540 Perl_warner(aTHX_ WARN_MALLOC, "%s", "Bad free() ignored");
1543 warn("%s", "Bad free() ignored");
1546 return; /* sanity */
1549 ASSERT(ovp->ov_rmagic == RMAGIC, "chunk's head overwrite");
1550 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
1552 MEM_SIZE nbytes = ovp->ov_size + 1;
1554 if ((i = nbytes & 3)) {
1557 ASSERT(*((char *)((caddr_t)ovp + nbytes - RSLOP + i))
1558 == RMAGIC_C, "chunk's tail overwrite");
1561 nbytes = (nbytes + 3) &~ 3;
1562 ASSERT(*(u_int *)((caddr_t)ovp + nbytes - RSLOP) == RMAGIC, "chunk's tail overwrite");
1564 ovp->ov_rmagic = RMAGIC - 1;
1566 ASSERT(OV_INDEX(ovp) < NBUCKETS, "chunk's head overwrite");
1567 size = OV_INDEX(ovp);
1570 ovp->ov_next = nextf[size];
1575 /* There is no need to do any locking in realloc (with an exception of
1576 trying to grow in place if we are at the end of the chain).
1577 If somebody calls us from a different thread with the same address,
1578 we are sole anyway. */
1581 Perl_realloc(void *mp, size_t nbytes)
1583 register MEM_SIZE onb;
1584 union overhead *ovp;
1587 register int bucket;
1588 int incr; /* 1 if does not fit, -1 if "easily" fits in a
1589 smaller bucket, otherwise 0. */
1590 char *cp = (char*)mp;
1592 #if defined(DEBUGGING) || !defined(PERL_CORE)
1593 MEM_SIZE size = nbytes;
1595 if ((long)nbytes < 0)
1596 croak("%s", "panic: realloc");
1599 BARK_64K_LIMIT("Reallocation",nbytes,size);
1601 return Perl_malloc(nbytes);
1603 ovp = (union overhead *)((caddr_t)cp
1604 - sizeof (union overhead) * CHUNK_SHIFT);
1605 bucket = OV_INDEX(ovp);
1607 #ifdef IGNORE_SMALL_BAD_FREE
1608 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
1609 && (OV_MAGIC(ovp, bucket) != MAGIC))
1611 if (OV_MAGIC(ovp, bucket) != MAGIC)
1614 static int bad_free_warn = -1;
1615 if (bad_free_warn == -1) {
1617 char *pbf = PerlEnv_getenv("PERL_BADFREE");
1618 bad_free_warn = (pbf) ? atoi(pbf) : 1;
1626 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1627 Perl_warner(aTHX_ WARN_MALLOC, "%srealloc() %signored",
1628 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
1629 ovp->ov_rmagic == RMAGIC - 1
1630 ? "of freed memory " : "");
1633 warn("%srealloc() %signored",
1634 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
1635 ovp->ov_rmagic == RMAGIC - 1 ? "of freed memory " : "");
1641 if (!PERL_IS_ALIVE || !PL_curcop || ckWARN_d(WARN_MALLOC))
1642 Perl_warner(aTHX_ WARN_MALLOC, "%s",
1643 "Bad realloc() ignored");
1646 warn("%s", "Bad realloc() ignored");
1649 return Nullch; /* sanity */
1652 onb = BUCKET_SIZE_REAL(bucket);
1654 * avoid the copy if same size block.
1655 * We are not agressive with boundary cases. Note that it might
1656 * (for a small number of cases) give false negative if
1657 * both new size and old one are in the bucket for
1658 * FIRST_BIG_POW2, but the new one is near the lower end.
1660 * We do not try to go to 1.5 times smaller bucket so far.
1662 if (nbytes > onb) incr = 1;
1664 #ifdef DO_NOT_TRY_HARDER_WHEN_SHRINKING
1665 if ( /* This is a little bit pessimal if PACK_MALLOC: */
1666 nbytes > ( (onb >> 1) - M_OVERHEAD )
1667 # ifdef TWO_POT_OPTIMIZE
1668 || (bucket == FIRST_BIG_POW2 && nbytes >= LAST_SMALL_BOUND )
1671 #else /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
1672 prev_bucket = ( (bucket > MAX_PACKED + 1)
1673 ? bucket - BUCKETS_PER_POW2
1675 if (nbytes > BUCKET_SIZE_REAL(prev_bucket))
1676 #endif /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
1680 #ifdef STRESS_REALLOC
1687 * Record new allocated size of block and
1688 * bound space with magic numbers.
1690 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
1691 int i, nb = ovp->ov_size + 1;
1696 ASSERT(*((char *)((caddr_t)ovp + nb - RSLOP + i)) == RMAGIC_C, "chunk's tail overwrite");
1700 ASSERT(*(u_int *)((caddr_t)ovp + nb - RSLOP) == RMAGIC, "chunk's tail overwrite");
1702 * Convert amount of memory requested into
1703 * closest block size stored in hash buckets
1704 * which satisfies request. Account for
1705 * space used per block for accounting.
1707 nbytes += M_OVERHEAD;
1708 ovp->ov_size = nbytes - 1;
1709 if ((i = nbytes & 3)) {
1712 *((char *)((caddr_t)ovp + nbytes - RSLOP + i))
1715 nbytes = (nbytes + 3) &~ 3;
1716 *((u_int *)((caddr_t)ovp + nbytes - RSLOP)) = RMAGIC;
1720 DEBUG_m(PerlIO_printf(Perl_debug_log,
1721 "0x%"UVxf": (%05lu) realloc %ld bytes inplace\n",
1722 PTR2UV(res),(unsigned long)(PL_an++),
1724 } else if (incr == 1 && (cp - M_OVERHEAD == last_op)
1725 && (onb > (1 << LOG_OF_MIN_ARENA))) {
1726 MEM_SIZE require, newarena = nbytes, pow;
1729 POW2_OPTIMIZE_ADJUST(newarena);
1730 newarena = newarena + M_OVERHEAD;
1731 /* newarena = (newarena + 3) &~ 3; */
1732 shiftr = (newarena - 1) >> LOG_OF_MIN_ARENA;
1733 pow = LOG_OF_MIN_ARENA + 1;
1734 /* apart from this loop, this is O(1) */
1735 while (shiftr >>= 1)
1737 newarena = (1 << pow) + POW2_OPTIMIZE_SURPLUS(pow * BUCKETS_PER_POW2);
1738 require = newarena - onb - M_OVERHEAD;
1741 if (cp - M_OVERHEAD == last_op /* We *still* are the last chunk */
1742 && getpages_adjacent(require)) {
1743 #ifdef DEBUGGING_MSTATS
1745 nmalloc[pow * BUCKETS_PER_POW2]++;
1747 *(cp - M_OVERHEAD) = pow * BUCKETS_PER_POW2; /* Fill index. */
1756 DEBUG_m(PerlIO_printf(Perl_debug_log,
1757 "0x%"UVxf": (%05lu) realloc %ld bytes the hard way\n",
1758 PTR2UV(cp),(unsigned long)(PL_an++),
1760 if ((res = (char*)Perl_malloc(nbytes)) == NULL)
1762 if (cp != res) /* common optimization */
1763 Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char);
1766 return ((Malloc_t)res);
1770 * Search ``srchlen'' elements of each free list for a block whose
1771 * header starts at ``freep''. If srchlen is -1 search the whole list.
1772 * Return bucket number, or -1 if not found.
1775 findbucket(union overhead *freep, int srchlen)
1777 register union overhead *p;
1780 for (i = 0; i < NBUCKETS; i++) {
1782 for (p = nextf[i]; p && j != srchlen; p = p->ov_next) {
1792 Perl_calloc(register size_t elements, register size_t size)
1794 long sz = elements * size;
1795 Malloc_t p = Perl_malloc(sz);
1798 memset((void*)p, 0, sz);
1804 Perl_strdup(const char *s)
1806 MEM_SIZE l = strlen(s);
1807 char *s1 = (char *)Perl_malloc(l+1);
1809 Copy(s, s1, (MEM_SIZE)(l+1), char);
1815 Perl_putenv(char *a)
1817 /* Sometimes system's putenv conflicts with my_setenv() - this is system
1818 malloc vs Perl's free(). */
1825 while (*val && *val != '=')
1830 if (l < sizeof(buf))
1833 var = Perl_malloc(l + 1);
1834 Copy(a, var, l, char);
1836 my_setenv(var, val+1);
1844 Perl_malloced_size(void *p)
1846 union overhead *ovp = (union overhead *)
1847 ((caddr_t)p - sizeof (union overhead) * CHUNK_SHIFT);
1848 int bucket = OV_INDEX(ovp);
1850 /* The caller wants to have a complete control over the chunk,
1851 disable the memory checking inside the chunk. */
1852 if (bucket <= MAX_SHORT_BUCKET) {
1853 MEM_SIZE size = BUCKET_SIZE_REAL(bucket);
1854 ovp->ov_size = size + M_OVERHEAD - 1;
1855 *((u_int *)((caddr_t)ovp + size + M_OVERHEAD - RSLOP)) = RMAGIC;
1858 return BUCKET_SIZE_REAL(bucket);
1861 # ifdef BUCKETS_ROOT2
1862 # define MIN_EVEN_REPORT 6
1864 # define MIN_EVEN_REPORT MIN_BUCKET
1868 Perl_get_mstats(pTHX_ perl_mstats_t *buf, int buflen, int level)
1870 #ifdef DEBUGGING_MSTATS
1872 register union overhead *p;
1873 struct chunk_chain_s* nextchain;
1875 buf->topbucket = buf->topbucket_ev = buf->topbucket_odd
1876 = buf->totfree = buf->total = buf->total_chain = 0;
1878 buf->minbucket = MIN_BUCKET;
1880 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
1881 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
1885 buf->ntotal[i] = nmalloc[i];
1887 buf->totfree += j * BUCKET_SIZE_REAL(i);
1888 buf->total += nmalloc[i] * BUCKET_SIZE_REAL(i);
1890 i % 2 ? (buf->topbucket_odd = i) : (buf->topbucket_ev = i);
1894 nextchain = chunk_chain;
1896 buf->total_chain += nextchain->size;
1897 nextchain = nextchain->next;
1899 buf->total_sbrk = goodsbrk + sbrk_slack;
1901 buf->sbrk_good = sbrk_good;
1902 buf->sbrk_slack = sbrk_slack;
1903 buf->start_slack = start_slack;
1904 buf->sbrked_remains = sbrked_remains;
1907 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
1910 buf->bucket_mem_size[i] = BUCKET_SIZE(i);
1911 buf->bucket_available_size[i] = BUCKET_SIZE_REAL(i);
1914 #endif /* defined DEBUGGING_MSTATS */
1915 return 0; /* XXX unused */
1918 * mstats - print out statistics about malloc
1920 * Prints two lines of numbers, one showing the length of the free list
1921 * for each size category, the second showing the number of mallocs -
1922 * frees for each size category.
1925 Perl_dump_mstats(pTHX_ char *s)
1927 #ifdef DEBUGGING_MSTATS
1929 register union overhead *p;
1930 perl_mstats_t buffer;
1931 unsigned long nf[NBUCKETS];
1932 unsigned long nt[NBUCKETS];
1933 struct chunk_chain_s* nextchain;
1937 get_mstats(&buffer, NBUCKETS, 0);
1940 PerlIO_printf(Perl_error_log,
1941 "Memory allocation statistics %s (buckets %ld(%ld)..%ld(%ld)\n",
1943 (long)BUCKET_SIZE_REAL(MIN_BUCKET),
1944 (long)BUCKET_SIZE(MIN_BUCKET),
1945 (long)BUCKET_SIZE_REAL(buffer.topbucket),
1946 (long)BUCKET_SIZE(buffer.topbucket));
1947 PerlIO_printf(Perl_error_log, "%8d free:", buffer.totfree);
1948 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
1949 PerlIO_printf(Perl_error_log,
1950 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
1952 : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")),
1955 #ifdef BUCKETS_ROOT2
1956 PerlIO_printf(Perl_error_log, "\n\t ");
1957 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
1958 PerlIO_printf(Perl_error_log,
1959 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
1961 : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")),
1965 PerlIO_printf(Perl_error_log, "\n%8d used:", buffer.total - buffer.totfree);
1966 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
1967 PerlIO_printf(Perl_error_log,
1968 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
1970 : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")),
1971 buffer.ntotal[i] - buffer.nfree[i]);
1973 #ifdef BUCKETS_ROOT2
1974 PerlIO_printf(Perl_error_log, "\n\t ");
1975 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
1976 PerlIO_printf(Perl_error_log,
1977 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
1979 : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")),
1980 buffer.ntotal[i] - buffer.nfree[i]);
1983 PerlIO_printf(Perl_error_log, "\nTotal sbrk(): %d/%d:%d. Odd ends: pad+heads+chain+tail: %d+%d+%d+%d.\n",
1984 buffer.total_sbrk, buffer.sbrks, buffer.sbrk_good,
1985 buffer.sbrk_slack, buffer.start_slack,
1986 buffer.total_chain, buffer.sbrked_remains);
1987 #endif /* DEBUGGING_MSTATS */
1991 #ifdef USE_PERL_SBRK
1993 # if defined(__MACHTEN_PPC__) || defined(NeXT) || defined(__NeXT__) || defined(PURIFY)
1994 # define PERL_SBRK_VIA_MALLOC
1996 * MachTen's malloc() returns a buffer aligned on a two-byte boundary.
1997 * While this is adequate, it may slow down access to longer data
1998 * types by forcing multiple memory accesses. It also causes
1999 * complaints when RCHECK is in force. So we allocate six bytes
2000 * more than we need to, and return an address rounded up to an
2001 * eight-byte boundary.
2003 * 980701 Dominic Dunlop <domo@computer.org>
2005 # define SYSTEM_ALLOC_ALIGNMENT 2
2008 # ifdef PERL_SBRK_VIA_MALLOC
2010 /* it may seem schizophrenic to use perl's malloc and let it call system */
2011 /* malloc, the reason for that is only the 3.2 version of the OS that had */
2012 /* frequent core dumps within nxzonefreenolock. This sbrk routine put an */
2013 /* end to the cores */
2015 # ifndef SYSTEM_ALLOC
2016 # define SYSTEM_ALLOC(a) malloc(a)
2018 # ifndef SYSTEM_ALLOC_ALIGNMENT
2019 # define SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES
2022 # endif /* PERL_SBRK_VIA_MALLOC */
2024 static IV Perl_sbrk_oldchunk;
2025 static long Perl_sbrk_oldsize;
2027 # define PERLSBRK_32_K (1<<15)
2028 # define PERLSBRK_64_K (1<<16)
2036 if (!size) return 0;
2038 reqsize = size; /* just for the DEBUG_m statement */
2041 size = (size + 0x7ff) & ~0x7ff;
2043 if (size <= Perl_sbrk_oldsize) {
2044 got = Perl_sbrk_oldchunk;
2045 Perl_sbrk_oldchunk += size;
2046 Perl_sbrk_oldsize -= size;
2048 if (size >= PERLSBRK_32_K) {
2051 size = PERLSBRK_64_K;
2054 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2055 size += NEEDED_ALIGNMENT - SYSTEM_ALLOC_ALIGNMENT;
2057 got = (IV)SYSTEM_ALLOC(size);
2058 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2059 got = (got + NEEDED_ALIGNMENT - 1) & ~(NEEDED_ALIGNMENT - 1);
2062 /* Chunk is small, register the rest for future allocs. */
2063 Perl_sbrk_oldchunk = got + reqsize;
2064 Perl_sbrk_oldsize = size - reqsize;
2068 DEBUG_m(PerlIO_printf(Perl_debug_log, "sbrk malloc size %ld (reqsize %ld), left size %ld, give addr 0x%"UVxf"\n",
2069 size, reqsize, Perl_sbrk_oldsize, PTR2UV(got)));
2074 #endif /* ! defined USE_PERL_SBRK */