6 * 'The Chamber of Records,' said Gimli. 'I guess that is where we now stand.'
8 * [p.321 of _The Lord of the Rings_, II/v: "The Bridge of Khazad-Dûm"]
11 /* This file contains Perl's own implementation of the malloc library.
12 * It is used if Configure decides that, on your platform, Perl's
13 * version is better than the OS's, or if you give Configure the
14 * -Dusemymalloc command-line option.
18 Here are some notes on configuring Perl's malloc.
20 There are two macros which serve as bulk disablers of advanced
21 features of this malloc: NO_FANCY_MALLOC, PLAIN_MALLOC (undef by
22 default). Look in the list of default values below to understand
23 their exact effect. Defining NO_FANCY_MALLOC returns malloc.c to the
24 state of the malloc in Perl 5.004. Additionally defining PLAIN_MALLOC
25 returns it to the state as of Perl 5.000.
27 Note that some of the settings below may be ignored in the code based
28 on values of other macros. The PERL_CORE symbol is only defined when
29 perl itself is being compiled (so malloc can make some assumptions
30 about perl's facilities being available to it).
32 Each config option has a short description, followed by its name,
33 default value, and a comment about the default (if applicable). Some
34 options take a precise value, while the others are just boolean.
35 The boolean ones are listed first.
37 # Read configuration settings from malloc_cfg.h
38 HAVE_MALLOC_CFG_H undef
40 # Enable code for an emergency memory pool in $^M. See perlvar.pod
41 # for a description of $^M.
42 PERL_EMERGENCY_SBRK !PLAIN_MALLOC
44 # Enable code for printing memory statistics.
45 DEBUGGING_MSTATS !PLAIN_MALLOC
47 # Move allocation info for small buckets into separate areas.
48 # Memory optimization (especially for small allocations, of the
49 # less than 64 bytes). Since perl usually makes a large number
50 # of small allocations, this is usually a win.
51 PACK_MALLOC (!PLAIN_MALLOC && !RCHECK)
53 # Add one page to big powers of two when calculating bucket size.
54 # This is targeted at big allocations, as are common in image
56 TWO_POT_OPTIMIZE !PLAIN_MALLOC
58 # Use intermediate bucket sizes between powers-of-two. This is
59 # generally a memory optimization, and a (small) speed pessimization.
60 BUCKETS_ROOT2 !NO_FANCY_MALLOC
62 # Do not check small deallocations for bad free(). Memory
63 # and speed optimization, error reporting pessimization.
64 IGNORE_SMALL_BAD_FREE (!NO_FANCY_MALLOC && !RCHECK)
66 # Use table lookup to decide in which bucket a given allocation will go.
67 SMALL_BUCKET_VIA_TABLE !NO_FANCY_MALLOC
69 # Use a perl-defined sbrk() instead of the (presumably broken or
70 # missing) system-supplied sbrk().
73 # Use system malloc() (or calloc() etc.) to emulate sbrk(). Normally
74 # only used with broken sbrk()s.
75 PERL_SBRK_VIA_MALLOC undef
77 # Which allocator to use if PERL_SBRK_VIA_MALLOC
78 SYSTEM_ALLOC(a) malloc(a)
80 # Minimal alignment (in bytes, should be a power of 2) of SYSTEM_ALLOC
81 SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES
83 # Disable memory overwrite checking with DEBUGGING. Memory and speed
84 # optimization, error reporting pessimization.
87 # Enable memory overwrite checking with DEBUGGING. Memory and speed
88 # pessimization, error reporting optimization
89 RCHECK (DEBUGGING && !NO_RCHECK)
91 # Do not overwrite uninit areas with DEBUGGING. Speed
92 # optimization, error reporting pessimization
95 # Overwrite uninit areas with DEBUGGING. Speed
96 # pessimization, error reporting optimization
97 MALLOC_FILL (DEBUGGING && !NO_RCHECK && !NO_MFILL)
99 # Do not check overwritten uninit areas with DEBUGGING. Speed
100 # optimization, error reporting pessimization
103 # Check overwritten uninit areas with DEBUGGING. Speed
104 # pessimization, error reporting optimization
105 MALLOC_FILL_CHECK (DEBUGGING && !NO_RCHECK && !NO_FILL_CHECK)
107 # Failed allocations bigger than this size croak (if
108 # PERL_EMERGENCY_SBRK is enabled) without touching $^M. See
109 # perlvar.pod for a description of $^M.
110 BIG_SIZE (1<<16) # 64K
112 # Starting from this power of two, add an extra page to the
113 # size of the bucket. This enables optimized allocations of sizes
114 # close to powers of 2. Note that the value is indexed at 0.
115 FIRST_BIG_POW2 15 # 32K, 16K is used too often
117 # Estimate of minimal memory footprint. malloc uses this value to
118 # request the most reasonable largest blocks of memory from the system.
121 # Round up sbrk()s to multiples of this.
124 # Round up sbrk()s to multiples of this percent of footprint.
127 # Round up sbrk()s to multiples of this multiple of 1/1000 of footprint.
128 MIN_SBRK_FRAC1000 (10 * MIN_SBRK_FRAC)
130 # Add this much memory to big powers of two to get the bucket size.
133 # This many sbrk() discontinuities should be tolerated even
134 # from the start without deciding that sbrk() is usually
136 SBRK_ALLOW_FAILURES 3
138 # This many continuous sbrk()s compensate for one discontinuous one.
139 SBRK_FAILURE_PRICE 50
141 # Some configurations may ask for 12-byte-or-so allocations which
142 # require 8-byte alignment (?!). In such situation one needs to
143 # define this to disable 12-byte bucket (will increase memory footprint)
144 STRICT_ALIGNMENT undef
146 # Do not allow configuration of runtime options at runtime
147 NO_MALLOC_DYNAMIC_CFG undef
149 # Do not allow configuration of runtime options via $ENV{PERL_MALLOC_OPT}
150 NO_PERL_MALLOC_ENV undef
152 [The variable consists of ;-separated parts of the form CODE=VALUE
153 with 1-character codes F, M, f, A, P, G, d, a, c for runtime
154 configuration of FIRST_SBRK, MIN_SBRK, MIN_SBRK_FRAC1000,
155 SBRK_ALLOW_FAILURES, SBRK_FAILURE_PRICE, sbrk_goodness,
156 filldead, fillalive, fillcheck. The last 3 are for DEBUGGING
157 build, and allow switching the tests for free()ed memory read,
158 uninit memory reads, and free()ed memory write.]
160 This implementation assumes that calling PerlIO_printf() does not
161 result in any memory allocation calls (used during a panic).
166 #ifdef HAVE_MALLOC_CFG_H
167 # include "malloc_cfg.h"
170 #ifndef NO_FANCY_MALLOC
171 # ifndef SMALL_BUCKET_VIA_TABLE
172 # define SMALL_BUCKET_VIA_TABLE
174 # ifndef BUCKETS_ROOT2
175 # define BUCKETS_ROOT2
177 # ifndef IGNORE_SMALL_BAD_FREE
178 # define IGNORE_SMALL_BAD_FREE
182 #ifndef PLAIN_MALLOC /* Bulk enable features */
186 # ifndef TWO_POT_OPTIMIZE
187 # define TWO_POT_OPTIMIZE
189 # ifndef PERL_EMERGENCY_SBRK
190 # define PERL_EMERGENCY_SBRK
192 # ifndef DEBUGGING_MSTATS
193 # define DEBUGGING_MSTATS
197 #define MIN_BUC_POW2 (sizeof(void*) > 4 ? 3 : 2) /* Allow for 4-byte arena. */
198 #define MIN_BUCKET (MIN_BUC_POW2 * BUCKETS_PER_POW2)
200 #define LOG_OF_MIN_ARENA 11
202 #if defined(DEBUGGING) && !defined(NO_RCHECK)
205 #if defined(DEBUGGING) && !defined(NO_RCHECK) && !defined(NO_MFILL) && !defined(MALLOC_FILL)
208 #if defined(DEBUGGING) && !defined(NO_RCHECK) && !defined(NO_FILL_CHECK) && !defined(MALLOC_FILL_CHECK)
209 # define MALLOC_FILL_CHECK
211 #if defined(RCHECK) && defined(IGNORE_SMALL_BAD_FREE)
212 # undef IGNORE_SMALL_BAD_FREE
215 * malloc.c (Caltech) 2/21/82
216 * Chris Kingsley, kingsley@cit-20.
218 * This is a very fast storage allocator. It allocates blocks of a small
219 * number of different sizes, and keeps free lists of each size. Blocks that
220 * don't exactly fit are passed up to the next larger size. In this
221 * implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long.
222 * If PACK_MALLOC is defined, small blocks are 2^n bytes long.
223 * This is designed for use in a program that uses vast quantities of memory,
224 * but bombs when it runs out.
226 * Modifications Copyright Ilya Zakharevich 1996-99.
228 * Still very quick, but much more thrifty. (Std config is 10% slower
229 * than it was, and takes 67% of old heap size for typical usage.)
231 * Allocations of small blocks are now table-driven to many different
232 * buckets. Sizes of really big buckets are increased to accommodate
233 * common size=power-of-2 blocks. Running-out-of-memory is made into
234 * an exception. Deeply configurable and thread-safe.
239 #define PERL_IN_MALLOC_C
241 #if defined(MULTIPLICITY)
242 # define croak2 Perl_croak_nocontext
244 # define croak2 croak
247 # define PERL_MAYBE_ALIVE PL_thr_key
249 # define PERL_MAYBE_ALIVE 1
253 # error "MYMALLOC is not defined"
257 # define MUTEX_LOCK(l)
261 # define MUTEX_UNLOCK(l)
265 # define MALLOC_LOCK MUTEX_LOCK(&PL_malloc_mutex)
268 #ifndef MALLOC_UNLOCK
269 # define MALLOC_UNLOCK MUTEX_UNLOCK(&PL_malloc_mutex)
272 # ifndef fatalcroak /* make depend */
273 # define fatalcroak(mess) (write(2, (mess), strlen(mess)), exit(2))
278 # define DEBUG_m(a) \
280 if (PERL_MAYBE_ALIVE && PERL_GET_THX) { \
282 if (DEBUG_m_TEST) { \
283 PL_debug &= ~DEBUG_m_FLAG; \
285 PL_debug |= DEBUG_m_FLAG; \
292 # define PERL_IS_ALIVE aTHX
294 # define PERL_IS_ALIVE TRUE
301 * The memory is broken into "blocks" which occupy multiples of 2K (and
302 * generally speaking, have size "close" to a power of 2). The addresses
303 * of such *unused* blocks are kept in nextf[i] with big enough i. (nextf
304 * is an array of linked lists.) (Addresses of used blocks are not known.)
306 * Moreover, since the algorithm may try to "bite" smaller blocks out
307 * of unused bigger ones, there are also regions of "irregular" size,
308 * managed separately, by a linked list chunk_chain.
310 * The third type of storage is the sbrk()ed-but-not-yet-used space, its
311 * end and size are kept in last_sbrk_top and sbrked_remains.
313 * Growing blocks "in place":
314 * ~~~~~~~~~~~~~~~~~~~~~~~~~
315 * The address of the block with the greatest address is kept in last_op
316 * (if not known, last_op is 0). If it is known that the memory above
317 * last_op is not continuous, or contains a chunk from chunk_chain,
318 * last_op is set to 0.
320 * The chunk with address last_op may be grown by expanding into
321 * sbrk()ed-but-not-yet-used space, or trying to sbrk() more continuous
324 * Management of last_op:
325 * ~~~~~~~~~~~~~~~~~~~~~
327 * free() never changes the boundaries of blocks, so is not relevant.
329 * The only way realloc() may change the boundaries of blocks is if it
330 * grows a block "in place". However, in the case of success such a
331 * chunk is automatically last_op, and it remains last_op. In the case
332 * of failure getpages_adjacent() clears last_op.
334 * malloc() may change blocks by calling morecore() only.
336 * morecore() may create new blocks by:
337 * a) biting pieces from chunk_chain (cannot create one above last_op);
338 * b) biting a piece from an unused block (if block was last_op, this
339 * may create a chunk from chain above last_op, thus last_op is
340 * invalidated in such a case).
341 * c) biting of sbrk()ed-but-not-yet-used space. This creates
342 * a block which is last_op.
343 * d) Allocating new pages by calling getpages();
345 * getpages() creates a new block. It marks last_op at the bottom of
346 * the chunk of memory it returns.
348 * Active pages footprint:
349 * ~~~~~~~~~~~~~~~~~~~~~~
350 * Note that we do not need to traverse the lists in nextf[i], just take
351 * the first element of this list. However, we *need* to traverse the
352 * list in chunk_chain, but most the time it should be a very short one,
353 * so we do not step on a lot of pages we are not going to use.
357 * get_from_bigger_buckets(): forget to increment price => Quite
361 /* I don't much care whether these are defined in sys/types.h--LAW */
363 #define u_char unsigned char
364 #define u_int unsigned int
366 * I removed the definition of u_bigint which appeared to be u_bigint = UV
367 * u_bigint was only used in TWOK_MASKED and TWOK_SHIFT
368 * where I have used PTR2UV. RMB
370 #define u_short unsigned short
372 #if defined(RCHECK) && defined(PACK_MALLOC)
377 * The description below is applicable if PACK_MALLOC is not defined.
379 * The overhead on a block is at least 4 bytes. When free, this space
380 * contains a pointer to the next free block, and the bottom two bits must
381 * be zero. When in use, the first byte is set to MAGIC, and the second
382 * byte is the size index. The remaining bytes are for alignment.
383 * If range checking is enabled and the size of the block fits
384 * in two bytes, then the top two bytes hold the size of the requested block
385 * plus the range checking words, and the header word MINUS ONE.
388 union overhead *ov_next; /* when free */
389 #if MEM_ALIGNBYTES > 4
390 double strut; /* alignment problems */
391 # if MEM_ALIGNBYTES > 8
392 char sstrut[MEM_ALIGNBYTES]; /* for the sizing */
397 * Keep the ovu_index and ovu_magic in this order, having a char
398 * field first gives alignment indigestion in some systems, such as
401 u_char ovu_index; /* bucket # */
402 u_char ovu_magic; /* magic number */
404 /* Subtract one to fit into u_short for an extra bucket */
405 u_short ovu_size; /* block size (requested + overhead - 1) */
406 u_int ovu_rmagic; /* range magic number */
409 #define ov_magic ovu.ovu_magic
410 #define ov_index ovu.ovu_index
411 #define ov_size ovu.ovu_size
412 #define ov_rmagic ovu.ovu_rmagic
415 #define MAGIC 0xff /* magic # on accounting info */
416 #define RMAGIC 0x55555555 /* magic # on range info */
417 #define RMAGIC_C 0x55 /* magic # on range info */
420 # define RMAGIC_SZ sizeof (u_int) /* Overhead at end of bucket */
421 # ifdef TWO_POT_OPTIMIZE
422 # define MAX_SHORT_BUCKET (12 * BUCKETS_PER_POW2) /* size-1 fits in short */
424 # define MAX_SHORT_BUCKET (13 * BUCKETS_PER_POW2)
430 #if !defined(PACK_MALLOC) && defined(BUCKETS_ROOT2)
431 # undef BUCKETS_ROOT2
435 # define BUCKET_TABLE_SHIFT 2
436 # define BUCKET_POW2_SHIFT 1
437 # define BUCKETS_PER_POW2 2
439 # define BUCKET_TABLE_SHIFT MIN_BUC_POW2
440 # define BUCKET_POW2_SHIFT 0
441 # define BUCKETS_PER_POW2 1
444 #if !defined(MEM_ALIGNBYTES) || ((MEM_ALIGNBYTES > 4) && !defined(STRICT_ALIGNMENT))
445 /* Figure out the alignment of void*. */
450 # define ALIGN_SMALL ((IV)((caddr_t)&(((struct aligner*)0)->p)))
452 # define ALIGN_SMALL MEM_ALIGNBYTES
455 #define IF_ALIGN_8(yes,no) ((ALIGN_SMALL>4) ? (yes) : (no))
458 # define MAX_BUCKET_BY_TABLE 13
459 static const u_short buck_size[MAX_BUCKET_BY_TABLE + 1] =
461 0, 0, 0, 0, 4, 4, 8, 12, 16, 24, 32, 48, 64, 80,
463 # define BUCKET_SIZE_NO_SURPLUS(i) ((i) % 2 ? buck_size[i] : (1 << ((i) >> BUCKET_POW2_SHIFT)))
464 # define BUCKET_SIZE_REAL(i) ((i) <= MAX_BUCKET_BY_TABLE \
465 ? ((size_t)buck_size[i]) \
466 : ((((size_t)1) << ((i) >> BUCKET_POW2_SHIFT)) \
468 + POW2_OPTIMIZE_SURPLUS(i)))
470 # define BUCKET_SIZE_NO_SURPLUS(i) (((size_t)1) << ((i) >> BUCKET_POW2_SHIFT))
471 # define BUCKET_SIZE(i) (BUCKET_SIZE_NO_SURPLUS(i) + POW2_OPTIMIZE_SURPLUS(i))
472 # define BUCKET_SIZE_REAL(i) (BUCKET_SIZE(i) - MEM_OVERHEAD(i))
477 /* In this case there are several possible layout of arenas depending
478 * on the size. Arenas are of sizes multiple to 2K, 2K-aligned, and
479 * have a size close to a power of 2.
481 * Arenas of the size >= 4K keep one chunk only. Arenas of size 2K
482 * may keep one chunk or multiple chunks. Here are the possible
485 * # One chunk only, chunksize 2^k + SOMETHING - ALIGN, k >= 11
487 * INDEX MAGIC1 UNUSED CHUNK1
489 * # Multichunk with sanity checking and chunksize 2^k-ALIGN, k>7
491 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 CHUNK2 CHUNK3 ...
493 * # Multichunk with sanity checking and size 2^k-ALIGN, k=7
495 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 UNUSED CHUNK2 CHUNK3 ...
497 * # Multichunk with sanity checking and size up to 80
499 * INDEX UNUSED MAGIC1 UNUSED MAGIC2 UNUSED ... CHUNK1 CHUNK2 CHUNK3 ...
501 * # No sanity check (usually up to 48=byte-long buckets)
502 * INDEX UNUSED CHUNK1 CHUNK2 ...
504 * Above INDEX and MAGIC are one-byte-long. Sizes of UNUSED are
505 * appropriate to keep algorithms simple and memory aligned. INDEX
506 * encodes the size of the chunk, while MAGICn encodes state (used,
507 * free or non-managed-by-us-so-it-indicates-a-bug) of CHUNKn. MAGIC
508 * is used for sanity checking purposes only. SOMETHING is 0 or 4K
509 * (to make size of big CHUNK accommodate allocations for powers of two
512 * [There is no need to alignment between chunks, since C rules ensure
513 * that structs which need 2^k alignment have sizeof which is
514 * divisible by 2^k. Thus as far as the last chunk is aligned at the
515 * end of the arena, and 2K-alignment does not contradict things,
516 * everything is going to be OK for sizes of chunks 2^n and 2^n +
517 * 2^k. Say, 80-bit buckets will be 16-bit aligned, and as far as we
518 * put allocations for requests in 65..80 range, all is fine.
520 * Note, however, that standard malloc() puts more strict
521 * requirements than the above C rules. Moreover, our algorithms of
522 * realloc() may break this idyll, but we suppose that realloc() does
523 * need not change alignment.]
525 * Is very important to make calculation of the offset of MAGICm as
526 * quick as possible, since it is done on each malloc()/free(). In
527 * fact it is so quick that it has quite little effect on the speed of
528 * doing malloc()/free(). [By default] We forego such calculations
529 * for small chunks, but only to save extra 3% of memory, not because
530 * of speed considerations.
532 * Here is the algorithm [which is the same for all the allocations
533 * schemes above], see OV_MAGIC(block,bucket). Let OFFSETm be the
534 * offset of the CHUNKm from the start of ARENA. Then offset of
535 * MAGICm is (OFFSET1 >> SHIFT) + ADDOFFSET. Here SHIFT and ADDOFFSET
536 * are numbers which depend on the size of the chunks only.
538 * Let as check some sanity conditions. Numbers OFFSETm>>SHIFT are
539 * different for all the chunks in the arena if 2^SHIFT is not greater
540 * than size of the chunks in the arena. MAGIC1 will not overwrite
541 * INDEX provided ADDOFFSET is >0 if OFFSET1 < 2^SHIFT. MAGIClast
542 * will not overwrite CHUNK1 if OFFSET1 > (OFFSETlast >> SHIFT) +
545 * Make SHIFT the maximal possible (there is no point in making it
546 * smaller). Since OFFSETlast is 2K - CHUNKSIZE, above restrictions
547 * give restrictions on OFFSET1 and on ADDOFFSET.
549 * In particular, for chunks of size 2^k with k>=6 we can put
550 * ADDOFFSET to be from 0 to 2^k - 2^(11-k), and have
551 * OFFSET1==chunksize. For chunks of size 80 OFFSET1 of 2K%80=48 is
552 * large enough to have ADDOFFSET between 1 and 16 (similarly for 96,
553 * when ADDOFFSET should be 1). In particular, keeping MAGICs for
554 * these sizes gives no additional size penalty.
556 * However, for chunks of size 2^k with k<=5 this gives OFFSET1 >=
557 * ADDOFSET + 2^(11-k). Keeping ADDOFFSET 0 allows for 2^(11-k)-2^(11-2k)
558 * chunks per arena. This is smaller than 2^(11-k) - 1 which are
559 * needed if no MAGIC is kept. [In fact, having a negative ADDOFFSET
560 * would allow for slightly more buckets per arena for k=2,3.]
562 * Similarly, for chunks of size 3/2*2^k with k<=5 MAGICs would span
563 * the area up to 2^(11-k)+ADDOFFSET. For k=4 this give optimal
564 * ADDOFFSET as -7..0. For k=3 ADDOFFSET can go up to 4 (with tiny
565 * savings for negative ADDOFFSET). For k=5 ADDOFFSET can go -1..16
566 * (with no savings for negative values).
568 * In particular, keeping ADDOFFSET 0 for sizes of chunks up to 2^6
569 * leads to tiny pessimizations in case of sizes 4, 8, 12, 24, and
570 * leads to no contradictions except for size=80 (or 96.)
572 * However, it also makes sense to keep no magic for sizes 48 or less.
573 * This is what we do. In this case one needs ADDOFFSET>=1 also for
574 * chunksizes 12, 24, and 48, unless one gets one less chunk per
577 * The algo of OV_MAGIC(block,bucket) keeps ADDOFFSET 0 until
578 * chunksize of 64, then makes it 1.
580 * This allows for an additional optimization: the above scheme leads
581 * to giant overheads for sizes 128 or more (one whole chunk needs to
582 * be sacrificed to keep INDEX). Instead we use chunks not of size
583 * 2^k, but of size 2^k-ALIGN. If we pack these chunks at the end of
584 * the arena, then the beginnings are still in different 2^k-long
585 * sections of the arena if k>=7 for ALIGN==4, and k>=8 if ALIGN=8.
586 * Thus for k>7 the above algo of calculating the offset of the magic
587 * will still give different answers for different chunks. And to
588 * avoid the overrun of MAGIC1 into INDEX, one needs ADDOFFSET of >=1.
589 * In the case k=7 we just move the first chunk an extra ALIGN
590 * backward inside the ARENA (this is done once per arena lifetime,
591 * thus is not a big overhead). */
592 # define MAX_PACKED_POW2 6
593 # define MAX_PACKED (MAX_PACKED_POW2 * BUCKETS_PER_POW2 + BUCKET_POW2_SHIFT)
594 # define MAX_POW2_ALGO ((1<<(MAX_PACKED_POW2 + 1)) - M_OVERHEAD)
595 # define TWOK_MASK nBIT_MASK(LOG_OF_MIN_ARENA)
596 # define TWOK_MASKED(x) (PTR2UV(x) & ~TWOK_MASK)
597 # define TWOK_SHIFT(x) (PTR2UV(x) & TWOK_MASK)
598 # define OV_INDEXp(block) (INT2PTR(u_char*,TWOK_MASKED(block)))
599 # define OV_INDEX(block) (*OV_INDEXp(block))
600 # define OV_MAGIC(block,bucket) (*(OV_INDEXp(block) + \
601 (TWOK_SHIFT(block)>> \
602 (bucket>>BUCKET_POW2_SHIFT)) + \
603 (bucket >= MIN_NEEDS_SHIFT ? 1 : 0)))
604 /* A bucket can have a shift smaller than it size, we need to
605 shift its magic number so it will not overwrite index: */
606 # ifdef BUCKETS_ROOT2
607 # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2 - 1) /* Shift 80 greater than chunk 64. */
609 # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2) /* Shift 128 greater than chunk 32. */
611 # define CHUNK_SHIFT 0
613 /* Number of active buckets of given ordinal. */
614 #ifdef IGNORE_SMALL_BAD_FREE
615 #define FIRST_BUCKET_WITH_CHECK (6 * BUCKETS_PER_POW2) /* 64 */
616 # define N_BLKS(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \
617 ? nBIT_MASK(LOG_OF_MIN_ARENA)/BUCKET_SIZE_NO_SURPLUS(bucket) \
620 # define N_BLKS(bucket) n_blks[bucket]
623 static const u_short n_blks[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
625 # if BUCKETS_PER_POW2==1
627 (MIN_BUC_POW2==2 ? 384 : 0),
628 224, 120, 62, 31, 16, 8, 4, 2
631 (MIN_BUC_POW2==2 ? 384 : 0), (MIN_BUC_POW2==2 ? 384 : 0), /* 4, 4 */
632 224, 149, 120, 80, 62, 41, 31, 25, 16, 16, 8, 8, 4, 4, 2, 2
636 /* Shift of the first bucket with the given ordinal inside 2K chunk. */
637 #ifdef IGNORE_SMALL_BAD_FREE
638 # define BLK_SHIFT(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \
639 ? ((1<<LOG_OF_MIN_ARENA) \
640 - BUCKET_SIZE_NO_SURPLUS(bucket) * N_BLKS(bucket)) \
643 # define BLK_SHIFT(bucket) blk_shift[bucket]
646 static const u_short blk_shift[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
648 # if BUCKETS_PER_POW2==1
650 (MIN_BUC_POW2==2 ? 512 : 0),
651 256, 128, 64, 64, /* 8 to 64 */
652 16*sizeof(union overhead),
653 8*sizeof(union overhead),
654 4*sizeof(union overhead),
655 2*sizeof(union overhead),
658 (MIN_BUC_POW2==2 ? 512 : 0), (MIN_BUC_POW2==2 ? 512 : 0),
659 256, 260, 128, 128, 64, 80, 64, 48, /* 8 to 96 */
660 16*sizeof(union overhead), 16*sizeof(union overhead),
661 8*sizeof(union overhead), 8*sizeof(union overhead),
662 4*sizeof(union overhead), 4*sizeof(union overhead),
663 2*sizeof(union overhead), 2*sizeof(union overhead),
667 # define NEEDED_ALIGNMENT 0x800 /* 2k boundaries */
668 # define WANTED_ALIGNMENT 0x800 /* 2k boundaries */
670 #else /* !PACK_MALLOC */
672 # define OV_MAGIC(block,bucket) (block)->ov_magic
673 # define OV_INDEX(block) (block)->ov_index
674 # define CHUNK_SHIFT 1
675 # define MAX_PACKED -1
676 # define NEEDED_ALIGNMENT MEM_ALIGNBYTES
677 # define WANTED_ALIGNMENT 0x400 /* 1k boundaries */
679 #endif /* !PACK_MALLOC */
681 #define M_OVERHEAD (sizeof(union overhead) + RMAGIC_SZ) /* overhead at start+end */
684 # define MEM_OVERHEAD(bucket) \
685 (bucket <= MAX_PACKED ? ((size_t)0) : M_OVERHEAD)
686 # ifdef SMALL_BUCKET_VIA_TABLE
687 # define START_SHIFTS_BUCKET ((MAX_PACKED_POW2 + 1) * BUCKETS_PER_POW2)
688 # define START_SHIFT MAX_PACKED_POW2
689 # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */
690 # define SIZE_TABLE_MAX 80
692 # define SIZE_TABLE_MAX 64
694 static const char bucket_of[] =
696 # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */
697 /* 0 to 15 in 4-byte increments. */
698 (sizeof(void*) > 4 ? 6 : 5), /* 4/8, 5-th bucket for better reports */
700 IF_ALIGN_8(8,7), 8, /* 16/12, 16 */
701 9, 9, 10, 10, /* 24, 32 */
702 11, 11, 11, 11, /* 48 */
703 12, 12, 12, 12, /* 64 */
704 13, 13, 13, 13, /* 80 */
705 13, 13, 13, 13 /* 80 */
706 # else /* !BUCKETS_ROOT2 */
707 /* 0 to 15 in 4-byte increments. */
708 (sizeof(void*) > 4 ? 3 : 2),
714 # endif /* !BUCKETS_ROOT2 */
716 # else /* !SMALL_BUCKET_VIA_TABLE */
717 # define START_SHIFTS_BUCKET MIN_BUCKET
718 # define START_SHIFT (MIN_BUC_POW2 - 1)
719 # endif /* !SMALL_BUCKET_VIA_TABLE */
720 #else /* !PACK_MALLOC */
721 # define MEM_OVERHEAD(bucket) M_OVERHEAD
722 # ifdef SMALL_BUCKET_VIA_TABLE
723 # undef SMALL_BUCKET_VIA_TABLE
725 # define START_SHIFTS_BUCKET MIN_BUCKET
726 # define START_SHIFT (MIN_BUC_POW2 - 1)
727 #endif /* !PACK_MALLOC */
730 * Big allocations are often of the size 2^n bytes. To make them a
731 * little bit better, make blocks of size 2^n+pagesize for big n.
734 #ifdef TWO_POT_OPTIMIZE
736 # ifndef PERL_PAGESIZE
737 # define PERL_PAGESIZE 4096
739 # ifndef FIRST_BIG_POW2
740 # define FIRST_BIG_POW2 15 /* 32K, 16K is used too often. */
742 # define FIRST_BIG_BLOCK (1<<FIRST_BIG_POW2)
743 /* If this value or more, check against bigger blocks. */
744 # define FIRST_BIG_BOUND (FIRST_BIG_BLOCK - M_OVERHEAD)
745 /* If less than this value, goes into 2^n-overhead-block. */
746 # define LAST_SMALL_BOUND ((FIRST_BIG_BLOCK>>1) - M_OVERHEAD)
748 # define POW2_OPTIMIZE_ADJUST(nbytes) \
749 ((nbytes >= FIRST_BIG_BOUND) ? nbytes -= PERL_PAGESIZE : 0)
750 # define POW2_OPTIMIZE_SURPLUS(bucket) \
751 ((size_t)((bucket >= FIRST_BIG_POW2 * BUCKETS_PER_POW2) ? PERL_PAGESIZE : 0))
753 #else /* !TWO_POT_OPTIMIZE */
754 # define POW2_OPTIMIZE_ADJUST(nbytes)
755 # define POW2_OPTIMIZE_SURPLUS(bucket) ((size_t)0)
756 #endif /* !TWO_POT_OPTIMIZE */
758 #define BARK_64K_LIMIT(what,nbytes,size)
761 # define MIN_SBRK 2048
765 # define FIRST_SBRK (48*1024)
768 /* Minimal sbrk in percents of what is already alloced. */
769 #ifndef MIN_SBRK_FRAC
770 # define MIN_SBRK_FRAC 3
773 #ifndef SBRK_ALLOW_FAILURES
774 # define SBRK_ALLOW_FAILURES 3
777 #ifndef SBRK_FAILURE_PRICE
778 # define SBRK_FAILURE_PRICE 50
781 static void morecore (int bucket);
782 # if defined(DEBUGGING)
783 static void botch (const char *diag, const char *s, const char *file, int line);
785 static void add_to_chain (void *p, MEM_SIZE size, MEM_SIZE chip);
786 static void* get_from_chain (MEM_SIZE size);
787 static void* get_from_bigger_buckets(int bucket, MEM_SIZE size);
788 static union overhead *getpages (MEM_SIZE needed, int *nblksp, int bucket);
789 static int getpages_adjacent(MEM_SIZE require);
791 #ifdef I_MACH_CTHREADS
793 # define MUTEX_LOCK(m) STMT_START { if (*m) mutex_lock(*m); } STMT_END
795 # define MUTEX_UNLOCK(m) STMT_START { if (*m) mutex_unlock(*m); } STMT_END
799 # define PTRSIZE sizeof(void*)
803 # define BITS_IN_PTR (8*PTRSIZE)
807 * nextf[i] is the pointer to the next free block of size 2^i. The
808 * smallest allocatable block is 8 bytes. The overhead information
809 * precedes the data area returned to the user.
811 #define NBUCKETS (BITS_IN_PTR*BUCKETS_PER_POW2 + 1)
812 static union overhead *nextf[NBUCKETS];
814 #if defined(PURIFY) && !defined(USE_PERL_SBRK)
815 # define USE_PERL_SBRK
819 # define sbrk(a) Perl_sbrk(a)
820 Malloc_t Perl_sbrk (int size);
821 #elif !defined(HAS_SBRK_PROTO) /* <unistd.h> usually takes care of this */
822 extern Malloc_t sbrk(int);
825 #ifndef MIN_SBRK_FRAC1000 /* Backward compatibility */
826 # define MIN_SBRK_FRAC1000 (MIN_SBRK_FRAC * 10)
829 #include "malloc_ctl.h"
831 #ifndef NO_MALLOC_DYNAMIC_CFG
832 # define PERL_MALLOC_OPT_CHARS "FMfAPGdac"
834 # ifndef FILL_DEAD_DEFAULT
835 # define FILL_DEAD_DEFAULT 1
837 # ifndef FILL_ALIVE_DEFAULT
838 # define FILL_ALIVE_DEFAULT 1
840 # ifndef FILL_CHECK_DEFAULT
841 # define FILL_CHECK_DEFAULT 1
844 static IV MallocCfg[MallocCfg_last] = {
850 SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE, /* sbrk_goodness */
851 FILL_DEAD_DEFAULT, /* FILL_DEAD */
852 FILL_ALIVE_DEFAULT, /* FILL_ALIVE */
853 FILL_CHECK_DEFAULT, /* FILL_CHECK */
854 0, /* MallocCfg_skip_cfg_env */
855 0, /* MallocCfg_cfg_env_read */
856 0, /* MallocCfg_emergency_buffer_size */
857 0, /* MallocCfg_emergency_buffer_prepared_size */
858 0 /* MallocCfg_emergency_buffer_last_req */
860 IV *MallocCfg_ptr = MallocCfg;
862 static char* MallocCfgP[MallocCfg_last] = {
863 0, /* MallocCfgP_emergency_buffer */
864 0, /* MallocCfgP_emergency_buffer_prepared */
866 char **MallocCfgP_ptr = MallocCfgP;
870 # undef MIN_SBRK_FRAC1000
871 # undef SBRK_ALLOW_FAILURES
872 # undef SBRK_FAILURE_PRICE
874 # define MIN_SBRK MallocCfg[MallocCfg_MIN_SBRK]
875 # define FIRST_SBRK MallocCfg[MallocCfg_FIRST_SBRK]
876 # define MIN_SBRK_FRAC1000 MallocCfg[MallocCfg_MIN_SBRK_FRAC1000]
877 # define SBRK_ALLOW_FAILURES MallocCfg[MallocCfg_SBRK_ALLOW_FAILURES]
878 # define SBRK_FAILURE_PRICE MallocCfg[MallocCfg_SBRK_FAILURE_PRICE]
880 # define sbrk_goodness MallocCfg[MallocCfg_sbrk_goodness]
882 # define emergency_buffer_size MallocCfg[MallocCfg_emergency_buffer_size]
883 # define emergency_buffer_last_req MallocCfg[MallocCfg_emergency_buffer_last_req]
885 # define FILL_DEAD MallocCfg[MallocCfg_filldead]
886 # define FILL_ALIVE MallocCfg[MallocCfg_fillalive]
887 # define FILL_CHECK_CFG MallocCfg[MallocCfg_fillcheck]
888 # define FILL_CHECK (FILL_DEAD && FILL_CHECK_CFG)
890 # define emergency_buffer MallocCfgP[MallocCfgP_emergency_buffer]
891 # define emergency_buffer_prepared MallocCfgP[MallocCfgP_emergency_buffer_prepared]
893 #else /* defined(NO_MALLOC_DYNAMIC_CFG) */
896 # define FILL_ALIVE 1
897 # define FILL_CHECK 1
898 static int sbrk_goodness = SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE;
900 # define NO_PERL_MALLOC_ENV
904 #ifdef DEBUGGING_MSTATS
906 * nmalloc[i] is the difference between the number of mallocs and frees
907 * for a given block size.
909 static u_int nmalloc[NBUCKETS];
910 static u_int sbrk_slack;
911 static u_int start_slack;
912 #else /* !( defined DEBUGGING_MSTATS ) */
913 # define sbrk_slack 0
916 static u_int goodsbrk;
918 #ifdef PERL_EMERGENCY_SBRK
921 # define BIG_SIZE (1<<16) /* 64K */
924 # ifdef NO_MALLOC_DYNAMIC_CFG
925 static MEM_SIZE emergency_buffer_size;
926 /* 0 if the last request for more memory succeeded.
927 Otherwise the size of the failing request. */
928 static MEM_SIZE emergency_buffer_last_req;
929 static char *emergency_buffer;
930 static char *emergency_buffer_prepared;
933 # ifndef emergency_sbrk_croak
934 # define emergency_sbrk_croak croak2
938 perl_get_emergency_buffer(IV *size)
941 /* First offense, give a possibility to recover by dieing. */
942 /* No malloc involved here: */
945 GV **gvp = (GV**)hv_fetchs(PL_defstash, "^M", FALSE);
947 if (!gvp) gvp = (GV**)hv_fetchs(PL_defstash, "\015", FALSE);
948 if (!gvp || !(sv = GvSV(*gvp)) || !SvPOK(sv)
949 || (SvLEN(sv) < (1<<LOG_OF_MIN_ARENA) - M_OVERHEAD))
950 return NULL; /* Now die die die... */
951 /* Got it, now detach SvPV: */
953 /* Check alignment: */
954 if ((PTR2UV(pv) - sizeof(union overhead)) & (NEEDED_ALIGNMENT - 1)) {
955 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
956 return NULL; /* die die die */
963 *size = malloced_size(pv) + M_OVERHEAD;
964 return pv - sizeof(union overhead);
966 # define PERL_GET_EMERGENCY_BUFFER(p) perl_get_emergency_buffer(p)
968 # ifndef NO_MALLOC_DYNAMIC_CFG
970 get_emergency_buffer(IV *size)
972 char *pv = emergency_buffer_prepared;
974 *size = MallocCfg[MallocCfg_emergency_buffer_prepared_size];
975 emergency_buffer_prepared = 0;
976 MallocCfg[MallocCfg_emergency_buffer_prepared_size] = 0;
980 # define GET_EMERGENCY_BUFFER(p) get_emergency_buffer(p)
981 # else /* NO_MALLOC_DYNAMIC_CFG */
982 # define GET_EMERGENCY_BUFFER(p) NULL
986 emergency_sbrk(MEM_SIZE size)
988 MEM_SIZE rsize = (((size - 1)>>LOG_OF_MIN_ARENA) + 1)<<LOG_OF_MIN_ARENA;
991 && (!emergency_buffer_last_req ||
992 (size < (MEM_SIZE)emergency_buffer_last_req))) {
993 /* Give the possibility to recover, but avoid an infinite cycle. */
995 emergency_buffer_last_req = size;
996 emergency_sbrk_croak("Out of memory during \"large\" request for %" UVuf
997 " bytes, total sbrk() is %" UVuf " bytes",
998 (UV)size, (UV)(goodsbrk + sbrk_slack));
1001 if ((MEM_SIZE)emergency_buffer_size >= rsize) {
1002 char *old = emergency_buffer;
1004 emergency_buffer_size -= rsize;
1005 emergency_buffer += rsize;
1008 /* First offense, give a possibility to recover by dieing. */
1009 /* No malloc involved here: */
1011 char *pv = GET_EMERGENCY_BUFFER(&Size);
1014 if (emergency_buffer_size) {
1015 add_to_chain(emergency_buffer, emergency_buffer_size, 0);
1016 emergency_buffer_size = 0;
1017 emergency_buffer = NULL;
1022 pv = PERL_GET_EMERGENCY_BUFFER(&Size);
1026 return (char *)-1; /* Now die die die... */
1029 /* Check alignment: */
1030 if (PTR2UV(pv) & (NEEDED_ALIGNMENT - 1)) {
1033 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
1034 return (char *)-1; /* die die die */
1037 emergency_buffer = pv;
1038 emergency_buffer_size = Size;
1042 emergency_sbrk_croak("Out of memory during request for %" UVuf
1043 " bytes, total sbrk() is %" UVuf " bytes",
1044 (UV)size, (UV)(goodsbrk + sbrk_slack));
1045 NOT_REACHED; /* NOTREACHED */
1049 #else /* !defined(PERL_EMERGENCY_SBRK) */
1050 # define emergency_sbrk(size) -1
1051 #endif /* defined PERL_EMERGENCY_SBRK */
1053 /* Don't use PerlIO buffered writes as they allocate memory. */
1054 #define MYMALLOC_WRITE2STDERR(s) PERL_UNUSED_RESULT(PerlLIO_write(PerlIO_fileno(PerlIO_stderr()),s,strlen(s)))
1058 #define ASSERT(p,diag) if (!(p)) botch(diag,STRINGIFY(p),__FILE__,__LINE__);
1061 botch(const char *diag, const char *s, const char *file, int line)
1064 if (!(PERL_MAYBE_ALIVE && PERL_GET_THX))
1067 if (PerlIO_printf(PerlIO_stderr(),
1068 "assertion botched (%s?): %s %s:%d\n",
1069 diag, s, file, line) != 0) {
1070 do_write: /* Can be initializing interpreter */
1071 MYMALLOC_WRITE2STDERR("assertion botched (");
1072 MYMALLOC_WRITE2STDERR(diag);
1073 MYMALLOC_WRITE2STDERR("?): ");
1074 MYMALLOC_WRITE2STDERR(s);
1075 MYMALLOC_WRITE2STDERR(" (");
1076 MYMALLOC_WRITE2STDERR(file);
1077 MYMALLOC_WRITE2STDERR(":");
1080 char *s = linebuf + sizeof(linebuf) - 1;
1084 *--s = '0' + (n % 10);
1086 MYMALLOC_WRITE2STDERR(s);
1088 MYMALLOC_WRITE2STDERR(")\n");
1094 #define ASSERT(p, diag)
1098 /* Fill should be long enough to cover long */
1100 fill_pat_4bytes(unsigned char *s, size_t nbytes, const unsigned char *fill)
1102 unsigned char *e = s + nbytes;
1104 const long lfill = *(long*)fill;
1106 if (PTR2UV(s) & (sizeof(long)-1)) { /* Align the pattern */
1107 int shift = sizeof(long) - (PTR2UV(s) & (sizeof(long)-1));
1108 unsigned const char *f = fill + sizeof(long) - shift;
1109 unsigned char *e1 = s + shift;
1115 while ((unsigned char*)(lp + 1) <= e)
1117 s = (unsigned char*)lp;
1121 /* Just malloc()ed */
1122 static const unsigned char fill_feedadad[] =
1123 {0xFE, 0xED, 0xAD, 0xAD, 0xFE, 0xED, 0xAD, 0xAD,
1124 0xFE, 0xED, 0xAD, 0xAD, 0xFE, 0xED, 0xAD, 0xAD};
1126 static const unsigned char fill_deadbeef[] =
1127 {0xDE, 0xAD, 0xBE, 0xEF, 0xDE, 0xAD, 0xBE, 0xEF,
1128 0xDE, 0xAD, 0xBE, 0xEF, 0xDE, 0xAD, 0xBE, 0xEF};
1129 # define FILL_DEADBEEF(s, n) \
1130 (void)(FILL_DEAD? (fill_pat_4bytes((s), (n), fill_deadbeef), 0) : 0)
1131 # define FILL_FEEDADAD(s, n) \
1132 (void)(FILL_ALIVE? (fill_pat_4bytes((s), (n), fill_feedadad), 0) : 0)
1134 # define FILL_DEADBEEF(s, n) ((void)0)
1135 # define FILL_FEEDADAD(s, n) ((void)0)
1136 # undef MALLOC_FILL_CHECK
1139 #ifdef MALLOC_FILL_CHECK
1141 cmp_pat_4bytes(unsigned char *s, size_t nbytes, const unsigned char *fill)
1143 unsigned char *e = s + nbytes;
1145 const long lfill = *(long*)fill;
1147 if (PTR2UV(s) & (sizeof(long)-1)) { /* Align the pattern */
1148 int shift = sizeof(long) - (PTR2UV(s) & (sizeof(long)-1));
1149 unsigned const char *f = fill + sizeof(long) - shift;
1150 unsigned char *e1 = s + shift;
1157 while ((unsigned char*)(lp + 1) <= e)
1160 s = (unsigned char*)lp;
1162 if (*s++ != *fill++)
1166 # define FILLCHECK_DEADBEEF(s, n) \
1167 ASSERT(!FILL_CHECK || !cmp_pat_4bytes(s, n, fill_deadbeef), \
1168 "free()ed/realloc()ed-away memory was overwritten")
1170 # define FILLCHECK_DEADBEEF(s, n) ((void)0)
1174 S_adjust_size_and_find_bucket(size_t *nbytes_p)
1180 PERL_ARGS_ASSERT_ADJUST_SIZE_AND_FIND_BUCKET;
1185 * Convert amount of memory requested into
1186 * closest block size stored in hash buckets
1187 * which satisfies request. Account for
1188 * space used per block for accounting.
1191 # ifdef SMALL_BUCKET_VIA_TABLE
1193 bucket = MIN_BUCKET;
1194 else if (nbytes <= SIZE_TABLE_MAX) {
1195 bucket = bucket_of[(nbytes - 1) >> BUCKET_TABLE_SHIFT];
1200 if (nbytes <= MAX_POW2_ALGO) goto do_shifts;
1205 POW2_OPTIMIZE_ADJUST(nbytes);
1206 nbytes += M_OVERHEAD;
1207 nbytes = (nbytes + 3) &~ 3;
1208 #if defined(PACK_MALLOC) && !defined(SMALL_BUCKET_VIA_TABLE)
1211 shiftr = (nbytes - 1) >> START_SHIFT;
1212 bucket = START_SHIFTS_BUCKET;
1213 /* apart from this loop, this is O(1) */
1214 while (shiftr >>= 1)
1215 bucket += BUCKETS_PER_POW2;
1224 Implements L<perlapi/C<Newx>> which you should use instead.
1230 Perl_malloc(size_t nbytes)
1234 #if defined(DEBUGGING) || defined(RCHECK)
1235 MEM_SIZE size = nbytes;
1238 /* A structure that has more than PTRDIFF_MAX bytes is unfortunately
1239 * legal in C, but in such, if two elements are far enough apart, we
1240 * can't legally find out how far apart they are. Limit the size of a
1241 * malloc so that pointer subtraction in the same structure is always
1243 if (nbytes > PTRDIFF_MAX) {
1245 MYMALLOC_WRITE2STDERR("Memory requests are limited to PTRDIFF_MAX"
1246 " bytes to prevent possible undefined"
1251 BARK_64K_LIMIT("Allocation",nbytes,nbytes);
1253 if ((long)nbytes < 0)
1254 croak("%s", "panic: malloc");
1257 bucket = adjust_size_and_find_bucket(&nbytes);
1260 * If nothing in hash bucket right now,
1261 * request more memory from the system.
1263 if (nextf[bucket] == NULL)
1265 if ((p = nextf[bucket]) == NULL) {
1270 #if defined(PLAIN_MALLOC) && defined(NO_FANCY_MALLOC)
1271 MYMALLOC_WRITE2STDERR("Out of memory!\n");
1274 char *eb = buff + sizeof(buff) - 1;
1278 MYMALLOC_WRITE2STDERR("Out of memory during request for ");
1279 #if defined(DEBUGGING) || defined(RCHECK)
1284 *--s = '0' + (n % 10);
1286 MYMALLOC_WRITE2STDERR(s);
1287 MYMALLOC_WRITE2STDERR(" bytes, total sbrk() is ");
1289 n = goodsbrk + sbrk_slack;
1291 *--s = '0' + (n % 10);
1293 MYMALLOC_WRITE2STDERR(s);
1294 MYMALLOC_WRITE2STDERR(" bytes!\n");
1295 #endif /* defined(PLAIN_MALLOC) && defined(NO_FANCY_MALLOC) */
1302 /* remove from linked list */
1304 if ( (PTR2UV(p) & (MEM_ALIGNBYTES - 1))
1305 /* Can't get this low */
1306 || (p && PTR2UV(p) < (1<<LOG_OF_MIN_ARENA)) ) {
1308 PerlIO_printf(PerlIO_stderr(),
1309 "Unaligned pointer in the free chain 0x%" UVxf "\n",
1312 if ( (PTR2UV(p->ov_next) & (MEM_ALIGNBYTES - 1))
1313 || (p->ov_next && PTR2UV(p->ov_next) < (1<<LOG_OF_MIN_ARENA)) ) {
1315 PerlIO_printf(PerlIO_stderr(),
1316 "Unaligned \"next\" pointer in the free "
1317 "chain 0x%" UVxf " at 0x%" UVxf "\n",
1318 PTR2UV(p->ov_next), PTR2UV(p));
1321 nextf[bucket] = p->ov_next;
1325 DEBUG_m(PerlIO_printf(Perl_debug_log,
1326 "%p: (%05lu) malloc %ld bytes\n",
1327 (Malloc_t)(p + CHUNK_SHIFT),
1328 (unsigned long)(PL_an++),
1331 FILLCHECK_DEADBEEF((unsigned char*)(p + CHUNK_SHIFT),
1332 BUCKET_SIZE_REAL(bucket) + RMAGIC_SZ);
1334 #ifdef IGNORE_SMALL_BAD_FREE
1335 if (bucket >= FIRST_BUCKET_WITH_CHECK)
1337 OV_MAGIC(p, bucket) = MAGIC;
1339 OV_INDEX(p) = bucket;
1343 * Record allocated size of block and
1344 * bound space with magic numbers.
1346 p->ov_rmagic = RMAGIC;
1347 if (bucket <= MAX_SHORT_BUCKET) {
1350 nbytes = size + M_OVERHEAD;
1351 p->ov_size = nbytes - 1;
1352 if ((i = nbytes & (RMAGIC_SZ-1))) {
1354 while (i--) /* nbytes - RMAGIC_SZ is end of alloced area */
1355 ((caddr_t)p + nbytes - RMAGIC_SZ)[i] = RMAGIC_C;
1357 /* Same at RMAGIC_SZ-aligned RMAGIC */
1358 nbytes = (nbytes + RMAGIC_SZ - 1) & ~(RMAGIC_SZ - 1);
1359 ((u_int *)((caddr_t)p + nbytes))[-1] = RMAGIC;
1361 FILL_FEEDADAD((unsigned char *)(p + CHUNK_SHIFT), size);
1363 return ((Malloc_t)(p + CHUNK_SHIFT));
1366 static char *last_sbrk_top;
1367 static char *last_op; /* This arena can be easily extended. */
1368 static MEM_SIZE sbrked_remains;
1370 #ifdef DEBUGGING_MSTATS
1374 struct chunk_chain_s {
1375 struct chunk_chain_s *next;
1378 static struct chunk_chain_s *chunk_chain;
1379 static int n_chunks;
1380 static char max_bucket;
1382 /* Cutoff a piece of one of the chunks in the chain. Prefer smaller chunk. */
1384 get_from_chain(MEM_SIZE size)
1386 struct chunk_chain_s *elt = chunk_chain, **oldp = &chunk_chain;
1387 struct chunk_chain_s **oldgoodp = NULL;
1388 long min_remain = LONG_MAX;
1391 if (elt->size >= size) {
1392 long remains = elt->size - size;
1393 if (remains >= 0 && remains < min_remain) {
1395 min_remain = remains;
1401 oldp = &( elt->next );
1404 if (!oldgoodp) return NULL;
1406 void *ret = *oldgoodp;
1407 struct chunk_chain_s *next = (*oldgoodp)->next;
1409 *oldgoodp = (struct chunk_chain_s *)((char*)ret + size);
1410 (*oldgoodp)->size = min_remain;
1411 (*oldgoodp)->next = next;
1414 void *ret = *oldgoodp;
1415 *oldgoodp = (*oldgoodp)->next;
1422 add_to_chain(void *p, MEM_SIZE size, MEM_SIZE chip)
1424 struct chunk_chain_s *next = chunk_chain;
1425 char *cp = (char*)p;
1428 chunk_chain = (struct chunk_chain_s *)cp;
1429 chunk_chain->size = size - chip;
1430 chunk_chain->next = next;
1435 get_from_bigger_buckets(int bucket, MEM_SIZE size)
1438 static int bucketprice[NBUCKETS];
1439 while (bucket <= max_bucket) {
1440 /* We postpone stealing from bigger buckets until we want it
1442 if (nextf[bucket] && bucketprice[bucket]++ >= price) {
1444 void *ret = (void*)(nextf[bucket] - 1 + CHUNK_SHIFT);
1445 bucketprice[bucket] = 0;
1446 if (((char*)nextf[bucket]) - M_OVERHEAD == last_op) {
1447 last_op = NULL; /* Disable optimization */
1449 nextf[bucket] = nextf[bucket]->ov_next;
1450 #ifdef DEBUGGING_MSTATS
1452 start_slack -= M_OVERHEAD;
1454 add_to_chain(ret, (BUCKET_SIZE_NO_SURPLUS(bucket) +
1455 POW2_OPTIMIZE_SURPLUS(bucket)),
1464 static union overhead *
1465 getpages(MEM_SIZE needed, int *nblksp, int bucket)
1467 /* Need to do (possibly expensive) system call. Try to
1468 optimize it for rare calling. */
1469 MEM_SIZE require = needed - sbrked_remains;
1471 union overhead *ovp;
1474 if (sbrk_goodness > 0) {
1475 if (!last_sbrk_top && require < (MEM_SIZE)FIRST_SBRK)
1476 require = FIRST_SBRK;
1477 else if (require < (MEM_SIZE)MIN_SBRK) require = MIN_SBRK;
1479 if (require < (Size_t)(goodsbrk * MIN_SBRK_FRAC1000 / 1000))
1480 require = goodsbrk * MIN_SBRK_FRAC1000 / 1000;
1481 require = ((require - 1 + MIN_SBRK) / MIN_SBRK) * MIN_SBRK;
1488 DEBUG_m(PerlIO_printf(Perl_debug_log,
1489 "sbrk(%ld) for %ld-byte-long arena\n",
1490 (long)require, (long) needed));
1491 cp = (char *)sbrk(require);
1492 #ifdef DEBUGGING_MSTATS
1495 if (cp == last_sbrk_top) {
1496 /* Common case, anything is fine. */
1498 ovp = (union overhead *) (cp - sbrked_remains);
1499 last_op = cp - sbrked_remains;
1500 sbrked_remains = require - (needed - sbrked_remains);
1501 } else if (cp == (char *)-1) { /* no more room! */
1502 ovp = (union overhead *)emergency_sbrk(needed);
1503 if (ovp == (union overhead *)-1)
1505 if (((char*)ovp) > last_op) { /* Cannot happen with current emergency_sbrk() */
1509 } else { /* Non-continuous or first sbrk(). */
1510 long add = sbrked_remains;
1513 if (sbrked_remains) { /* Put rest into chain, we
1514 cannot use it right now. */
1515 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1519 /* Second, check alignment. */
1522 /* WANTED_ALIGNMENT may be more than NEEDED_ALIGNMENT, but this may
1523 improve performance of memory access. */
1524 if (PTR2UV(cp) & (WANTED_ALIGNMENT - 1)) { /* Not aligned. */
1525 slack = WANTED_ALIGNMENT - (PTR2UV(cp) & (WANTED_ALIGNMENT - 1));
1530 DEBUG_m(PerlIO_printf(Perl_debug_log,
1531 "sbrk(%ld) to fix non-continuous/off-page sbrk:\n\t%ld for alignment,\t%ld were assumed to come from the tail of the previous sbrk\n",
1532 (long)add, (long) slack,
1533 (long) sbrked_remains));
1534 newcp = (char *)sbrk(add);
1535 #if defined(DEBUGGING_MSTATS)
1539 if (newcp != cp + require) {
1540 /* Too bad: even rounding sbrk() is not continuous.*/
1541 DEBUG_m(PerlIO_printf(Perl_debug_log,
1542 "failed to fix bad sbrk()\n"));
1546 fatalcroak("panic: Off-page sbrk\n");
1549 if (sbrked_remains) {
1551 #if defined(DEBUGGING_MSTATS)
1552 sbrk_slack += require;
1555 DEBUG_m(PerlIO_printf(Perl_debug_log,
1556 "straight sbrk(%ld)\n",
1558 cp = (char *)sbrk(require);
1559 #ifdef DEBUGGING_MSTATS
1562 if (cp == (char *)-1)
1565 sbrk_goodness = -1; /* Disable optimization!
1566 Continue with not-aligned... */
1569 require += sbrked_remains;
1573 if (last_sbrk_top) {
1574 sbrk_goodness -= SBRK_FAILURE_PRICE;
1577 ovp = (union overhead *) cp;
1579 * Round up to minimum allocation size boundary
1580 * and deduct from block count to reflect.
1583 # if NEEDED_ALIGNMENT > MEM_ALIGNBYTES
1584 if (PTR2UV(ovp) & (NEEDED_ALIGNMENT - 1))
1585 fatalcroak("Misalignment of sbrk()\n");
1588 if (PTR2UV(ovp) & (MEM_ALIGNBYTES - 1)) {
1589 DEBUG_m(PerlIO_printf(Perl_debug_log,
1590 "fixing sbrk(): %d bytes off machine alignment\n",
1591 (int)(PTR2UV(ovp) & (MEM_ALIGNBYTES - 1))));
1592 ovp = INT2PTR(union overhead *,(PTR2UV(ovp) + MEM_ALIGNBYTES) &
1593 (MEM_ALIGNBYTES - 1));
1595 # if defined(DEBUGGING_MSTATS)
1596 /* This is only approx. if TWO_POT_OPTIMIZE: */
1597 sbrk_slack += (1 << (bucket >> BUCKET_POW2_SHIFT));
1600 ; /* Finish "else" */
1601 sbrked_remains = require - needed;
1604 #if !defined(PLAIN_MALLOC) && !defined(NO_FANCY_MALLOC)
1605 emergency_buffer_last_req = 0;
1607 last_sbrk_top = cp + require;
1608 #ifdef DEBUGGING_MSTATS
1609 goodsbrk += require;
1615 getpages_adjacent(MEM_SIZE require)
1617 if (require <= sbrked_remains) {
1618 sbrked_remains -= require;
1622 require -= sbrked_remains;
1623 /* We do not try to optimize sbrks here, we go for place. */
1624 cp = (char*) sbrk(require);
1625 #ifdef DEBUGGING_MSTATS
1627 goodsbrk += require;
1629 if (cp == last_sbrk_top) {
1631 last_sbrk_top = cp + require;
1633 if (cp == (char*)-1) { /* Out of memory */
1634 #ifdef DEBUGGING_MSTATS
1635 goodsbrk -= require;
1639 /* Report the failure: */
1641 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1643 add_to_chain((void*)cp, require, 0);
1644 sbrk_goodness -= SBRK_FAILURE_PRICE;
1656 * Allocate more memory to the indicated bucket.
1659 morecore(int bucket)
1661 union overhead *ovp;
1662 int rnu; /* 2^rnu bytes will be requested */
1663 int nblks; /* become nblks blocks of the desired size */
1664 MEM_SIZE siz, needed;
1665 static int were_called = 0;
1669 #ifndef NO_PERL_MALLOC_ENV
1671 /* It's our first time. Initialize ourselves */
1672 were_called = 1; /* Avoid a loop */
1673 if (!MallocCfg[MallocCfg_skip_cfg_env]) {
1674 char *s = getenv("PERL_MALLOC_OPT"), *t = s;
1676 const char *opts = PERL_MALLOC_OPT_CHARS;
1679 while ( t && t[0] && t[1] == '='
1680 && ((off = strchr(opts, *t))) ) {
1685 val = 10*val + *t++ - '0';
1686 if (!*t || *t == ';') {
1687 if (MallocCfg[off - opts] != val)
1689 MallocCfg[off - opts] = val;
1696 MYMALLOC_WRITE2STDERR("Unrecognized part of PERL_MALLOC_OPT: \"");
1697 MYMALLOC_WRITE2STDERR(t);
1698 MYMALLOC_WRITE2STDERR("\"\n");
1701 MallocCfg[MallocCfg_cfg_env_read] = 1;
1705 if (bucket == sizeof(MEM_SIZE)*8*BUCKETS_PER_POW2) {
1707 croak2("%s", "Out of memory during ridiculously large request");
1709 if (bucket > max_bucket)
1710 max_bucket = bucket;
1712 rnu = ( (bucket <= (LOG_OF_MIN_ARENA << BUCKET_POW2_SHIFT))
1714 : (bucket >> BUCKET_POW2_SHIFT) );
1715 /* This may be overwritten later: */
1716 nblks = 1 << (rnu - (bucket >> BUCKET_POW2_SHIFT)); /* how many blocks to get */
1717 needed = ((MEM_SIZE)1 << rnu) + POW2_OPTIMIZE_SURPLUS(bucket);
1718 if (nextf[rnu << BUCKET_POW2_SHIFT]) { /* 2048b bucket. */
1719 ovp = nextf[rnu << BUCKET_POW2_SHIFT] - 1 + CHUNK_SHIFT;
1720 nextf[rnu << BUCKET_POW2_SHIFT]
1721 = nextf[rnu << BUCKET_POW2_SHIFT]->ov_next;
1722 #ifdef DEBUGGING_MSTATS
1723 nmalloc[rnu << BUCKET_POW2_SHIFT]--;
1724 start_slack -= M_OVERHEAD;
1726 DEBUG_m(PerlIO_printf(Perl_debug_log,
1727 "stealing %ld bytes from %ld arena\n",
1728 (long) needed, (long) rnu << BUCKET_POW2_SHIFT));
1729 } else if (chunk_chain
1730 && (ovp = (union overhead*) get_from_chain(needed))) {
1731 DEBUG_m(PerlIO_printf(Perl_debug_log,
1732 "stealing %ld bytes from chain\n",
1734 } else if ( (ovp = (union overhead*)
1735 get_from_bigger_buckets((rnu << BUCKET_POW2_SHIFT) + 1,
1737 DEBUG_m(PerlIO_printf(Perl_debug_log,
1738 "stealing %ld bytes from bigger buckets\n",
1740 } else if (needed <= sbrked_remains) {
1741 ovp = (union overhead *)(last_sbrk_top - sbrked_remains);
1742 sbrked_remains -= needed;
1743 last_op = (char*)ovp;
1745 ovp = getpages(needed, &nblks, bucket);
1749 FILL_DEADBEEF((unsigned char*)ovp, needed);
1752 * Add new memory allocated to that on
1753 * free list for this hash bucket.
1755 siz = BUCKET_SIZE_NO_SURPLUS(bucket); /* No surplus if nblks > 1 */
1757 *(u_char*)ovp = bucket; /* Fill index. */
1758 if (bucket <= MAX_PACKED) {
1759 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1760 nblks = N_BLKS(bucket);
1761 # ifdef DEBUGGING_MSTATS
1762 start_slack += BLK_SHIFT(bucket);
1764 } else if (bucket < LOG_OF_MIN_ARENA * BUCKETS_PER_POW2) {
1765 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1766 siz -= sizeof(union overhead);
1767 } else ovp++; /* One chunk per block. */
1768 #endif /* PACK_MALLOC */
1769 nextf[bucket] = ovp;
1770 #ifdef DEBUGGING_MSTATS
1771 nmalloc[bucket] += nblks;
1772 if (bucket > MAX_PACKED) {
1773 start_slack += M_OVERHEAD * nblks;
1777 while (--nblks > 0) {
1778 ovp->ov_next = (union overhead *)((caddr_t)ovp + siz);
1779 ovp = (union overhead *)((caddr_t)ovp + siz);
1781 /* Not all sbrks return zeroed memory.*/
1782 ovp->ov_next = (union overhead *)NULL;
1784 if (bucket == 7*BUCKETS_PER_POW2) { /* Special case, explanation is above. */
1785 union overhead *n_op = nextf[7*BUCKETS_PER_POW2]->ov_next;
1786 nextf[7*BUCKETS_PER_POW2] =
1787 (union overhead *)((caddr_t)nextf[7*BUCKETS_PER_POW2]
1788 - sizeof(union overhead));
1789 nextf[7*BUCKETS_PER_POW2]->ov_next = n_op;
1791 #endif /* !PACK_MALLOC */
1797 Implements L<perlapi/C<Safefree>> which you should use instead.
1803 Perl_mfree(Malloc_t where)
1806 union overhead *ovp;
1807 char *cp = (char*)where;
1812 DEBUG_m(PerlIO_printf(Perl_debug_log,
1813 "0x%" UVxf ": (%05lu) free\n",
1814 PTR2UV(cp), (unsigned long)(PL_an++)));
1819 if (PTR2UV(cp) & (MEM_ALIGNBYTES - 1))
1820 croak("%s", "wrong alignment in free()");
1822 ovp = (union overhead *)((caddr_t)cp
1823 - sizeof (union overhead) * CHUNK_SHIFT);
1825 bucket = OV_INDEX(ovp);
1827 #ifdef IGNORE_SMALL_BAD_FREE
1828 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
1829 && (OV_MAGIC(ovp, bucket) != MAGIC))
1831 if (OV_MAGIC(ovp, bucket) != MAGIC)
1834 static int bad_free_warn = -1;
1835 if (bad_free_warn == -1) {
1837 char *pbf = PerlEnv_getenv("PERL_BADFREE");
1838 bad_free_warn = (pbf) ? strNE("0", pbf) : 1;
1845 if (!PERL_IS_ALIVE || !PL_curcop)
1846 Perl_ck_warner_d(aTHX_ packWARN(WARN_MALLOC), "%s free() ignored (RMAGIC, PERL_CORE)",
1847 ovp->ov_rmagic == RMAGIC - 1 ?
1848 "Duplicate" : "Bad");
1853 if (!PERL_IS_ALIVE || !PL_curcop)
1854 Perl_ck_warner_d(aTHX_ packWARN(WARN_MALLOC), "%s", "Bad free() ignored (PERL_CORE)");
1857 return; /* sanity */
1860 ASSERT(ovp->ov_rmagic == RMAGIC, "chunk's head overwrite");
1861 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
1863 MEM_SIZE nbytes = ovp->ov_size + 1;
1865 if ((i = nbytes & (RMAGIC_SZ-1))) {
1867 while (i--) { /* nbytes - RMAGIC_SZ is end of alloced area */
1868 ASSERT(((caddr_t)ovp + nbytes - RMAGIC_SZ)[i] == RMAGIC_C,
1869 "chunk's tail overwrite");
1872 /* Same at RMAGIC_SZ-aligned RMAGIC */
1873 nbytes = (nbytes + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ-1);
1874 ASSERT(((u_int *)((caddr_t)ovp + nbytes))[-1] == RMAGIC,
1875 "chunk's tail overwrite");
1876 FILLCHECK_DEADBEEF((unsigned char*)((caddr_t)ovp + nbytes),
1877 BUCKET_SIZE(OV_INDEX(ovp)) - nbytes);
1879 FILL_DEADBEEF((unsigned char*)(ovp+CHUNK_SHIFT),
1880 BUCKET_SIZE_REAL(OV_INDEX(ovp)) + RMAGIC_SZ);
1881 ovp->ov_rmagic = RMAGIC - 1;
1883 ASSERT(OV_INDEX(ovp) < NBUCKETS, "chunk's head overwrite");
1884 size = OV_INDEX(ovp);
1887 ovp->ov_next = nextf[size];
1895 Implements L<perlapi/C<Renew>> which you should use instead.
1900 /* There is no need to do any locking in realloc (with an exception of
1901 trying to grow in place if we are at the end of the chain).
1902 If somebody calls us from a different thread with the same address,
1903 we are sole anyway. */
1906 Perl_realloc(void *mp, size_t nbytes)
1909 union overhead *ovp;
1913 int incr; /* 1 if does not fit, -1 if "easily" fits in a
1914 smaller bucket, otherwise 0. */
1915 char *cp = (char*)mp;
1918 MEM_SIZE size = nbytes;
1920 if ((long)nbytes < 0)
1921 croak("%s", "panic: realloc");
1924 BARK_64K_LIMIT("Reallocation",nbytes,size);
1926 return Perl_malloc(nbytes);
1928 ovp = (union overhead *)((caddr_t)cp
1929 - sizeof (union overhead) * CHUNK_SHIFT);
1930 bucket = OV_INDEX(ovp);
1932 #ifdef IGNORE_SMALL_BAD_FREE
1933 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
1934 && (OV_MAGIC(ovp, bucket) != MAGIC))
1936 if (OV_MAGIC(ovp, bucket) != MAGIC)
1939 static int bad_free_warn = -1;
1940 if (bad_free_warn == -1) {
1942 char *pbf = PerlEnv_getenv("PERL_BADFREE");
1943 bad_free_warn = (pbf) ? strNE("0", pbf) : 1;
1950 if (!PERL_IS_ALIVE || !PL_curcop)
1951 Perl_ck_warner_d(aTHX_ packWARN(WARN_MALLOC), "%srealloc() %signored",
1952 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
1953 ovp->ov_rmagic == RMAGIC - 1
1954 ? "of freed memory " : "");
1959 if (!PERL_IS_ALIVE || !PL_curcop)
1960 Perl_ck_warner_d(aTHX_ packWARN(WARN_MALLOC), "%s",
1961 "Bad realloc() ignored");
1964 return NULL; /* sanity */
1967 onb = BUCKET_SIZE_REAL(bucket);
1969 * avoid the copy if same size block.
1970 * We are not aggressive with boundary cases. Note that it might
1971 * (for a small number of cases) give false negative if
1972 * both new size and old one are in the bucket for
1973 * FIRST_BIG_POW2, but the new one is near the lower end.
1975 * We do not try to go to 1.5 times smaller bucket so far.
1977 if (nbytes > onb) incr = 1;
1979 #ifdef DO_NOT_TRY_HARDER_WHEN_SHRINKING
1980 if ( /* This is a little bit pessimal if PACK_MALLOC: */
1981 nbytes > ( (onb >> 1) - M_OVERHEAD )
1982 # ifdef TWO_POT_OPTIMIZE
1983 || (bucket == FIRST_BIG_POW2 && nbytes >= LAST_SMALL_BOUND )
1986 #else /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
1987 prev_bucket = ( (bucket > MAX_PACKED + 1)
1988 ? bucket - BUCKETS_PER_POW2
1990 if (nbytes > BUCKET_SIZE_REAL(prev_bucket))
1991 #endif /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
1995 #ifdef STRESS_REALLOC
2002 * Record new allocated size of block and
2003 * bound space with magic numbers.
2005 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
2006 int i, nb = ovp->ov_size + 1;
2008 if ((i = nb & (RMAGIC_SZ-1))) {
2010 while (i--) { /* nb - RMAGIC_SZ is end of alloced area */
2011 ASSERT(((caddr_t)ovp + nb - RMAGIC_SZ)[i] == RMAGIC_C, "chunk's tail overwrite");
2014 /* Same at RMAGIC_SZ-aligned RMAGIC */
2015 nb = (nb + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ-1);
2016 ASSERT(((u_int *)((caddr_t)ovp + nb))[-1] == RMAGIC,
2017 "chunk's tail overwrite");
2018 FILLCHECK_DEADBEEF((unsigned char*)((caddr_t)ovp + nb),
2019 BUCKET_SIZE(OV_INDEX(ovp)) - nb);
2020 if (nbytes > ovp->ov_size + 1 - M_OVERHEAD)
2021 FILL_FEEDADAD((unsigned char*)cp + ovp->ov_size + 1 - M_OVERHEAD,
2022 nbytes - (ovp->ov_size + 1 - M_OVERHEAD));
2024 FILL_DEADBEEF((unsigned char*)cp + nbytes,
2025 nb - M_OVERHEAD + RMAGIC_SZ - nbytes);
2027 * Convert amount of memory requested into
2028 * closest block size stored in hash buckets
2029 * which satisfies request. Account for
2030 * space used per block for accounting.
2032 nbytes += M_OVERHEAD;
2033 ovp->ov_size = nbytes - 1;
2034 if ((i = nbytes & (RMAGIC_SZ-1))) {
2036 while (i--) /* nbytes - RMAGIC_SZ is end of alloced area */
2037 ((caddr_t)ovp + nbytes - RMAGIC_SZ)[i]
2040 /* Same at RMAGIC_SZ-aligned RMAGIC */
2041 nbytes = (nbytes + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ - 1);
2042 ((u_int *)((caddr_t)ovp + nbytes))[-1] = RMAGIC;
2046 DEBUG_m(PerlIO_printf(Perl_debug_log,
2047 "0x%" UVxf ": (%05lu) realloc %ld bytes inplace\n",
2048 PTR2UV(res),(unsigned long)(PL_an++),
2050 } else if (incr == 1 && (cp - M_OVERHEAD == last_op)
2051 && (onb > (1 << LOG_OF_MIN_ARENA))) {
2052 MEM_SIZE require, newarena = nbytes, pow;
2055 POW2_OPTIMIZE_ADJUST(newarena);
2056 newarena = newarena + M_OVERHEAD;
2057 /* newarena = (newarena + 3) &~ 3; */
2058 shiftr = (newarena - 1) >> LOG_OF_MIN_ARENA;
2059 pow = LOG_OF_MIN_ARENA + 1;
2060 /* apart from this loop, this is O(1) */
2061 while (shiftr >>= 1)
2063 newarena = (1 << pow) + POW2_OPTIMIZE_SURPLUS(pow * BUCKETS_PER_POW2);
2064 require = newarena - onb - M_OVERHEAD;
2067 if (cp - M_OVERHEAD == last_op /* We *still* are the last chunk */
2068 && getpages_adjacent(require)) {
2069 #ifdef DEBUGGING_MSTATS
2071 nmalloc[pow * BUCKETS_PER_POW2]++;
2073 if (pow * BUCKETS_PER_POW2 > (MEM_SIZE)max_bucket)
2074 max_bucket = pow * BUCKETS_PER_POW2;
2075 *(cp - M_OVERHEAD) = pow * BUCKETS_PER_POW2; /* Fill index. */
2084 DEBUG_m(PerlIO_printf(Perl_debug_log,
2085 "0x%" UVxf ": (%05lu) realloc %ld bytes the hard way\n",
2086 PTR2UV(cp),(unsigned long)(PL_an++),
2088 if ((res = (char*)Perl_malloc(nbytes)) == NULL)
2090 if (cp != res) /* common optimization */
2091 Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char);
2094 return ((Malloc_t)res);
2100 Implements L<perlapi/C<Newxz>> which you should use instead.
2106 Perl_calloc(size_t elements, size_t size)
2108 long sz = elements * size;
2109 Malloc_t p = Perl_malloc(sz);
2112 memset((void*)p, 0, sz);
2118 Perl_strdup(const char *s)
2120 MEM_SIZE l = strlen(s);
2121 char *s1 = (char *)Perl_malloc(l+1);
2123 return (char *)CopyD(s, s1, (MEM_SIZE)(l+1), char);
2127 Perl_putenv(char *a)
2129 /* Sometimes system's putenv conflicts with my_setenv() - this is system
2130 malloc vs Perl's free(). */
2137 while (*val && *val != '=')
2142 if (l < sizeof(buf))
2145 var = (char *)Perl_malloc(l + 1);
2146 Copy(a, var, l, char);
2148 my_setenv(var, val+1);
2155 Perl_malloced_size(void *p)
2157 union overhead * const ovp = (union overhead *)
2158 ((caddr_t)p - sizeof (union overhead) * CHUNK_SHIFT);
2159 const int bucket = OV_INDEX(ovp);
2161 PERL_ARGS_ASSERT_MALLOCED_SIZE;
2164 /* The caller wants to have a complete control over the chunk,
2165 disable the memory checking inside the chunk. */
2166 if (bucket <= MAX_SHORT_BUCKET) {
2167 const MEM_SIZE size = BUCKET_SIZE_REAL(bucket);
2168 ovp->ov_size = size + M_OVERHEAD - 1;
2169 *((u_int *)((caddr_t)ovp + size + M_OVERHEAD - RMAGIC_SZ)) = RMAGIC;
2172 return BUCKET_SIZE_REAL(bucket);
2177 Perl_malloc_good_size(size_t wanted)
2179 return BUCKET_SIZE_REAL(adjust_size_and_find_bucket(&wanted));
2182 # ifdef BUCKETS_ROOT2
2183 # define MIN_EVEN_REPORT 6
2185 # define MIN_EVEN_REPORT MIN_BUCKET
2189 Perl_get_mstats(pTHX_ perl_mstats_t *buf, int buflen, int level)
2191 #ifdef DEBUGGING_MSTATS
2194 struct chunk_chain_s* nextchain;
2196 PERL_ARGS_ASSERT_GET_MSTATS;
2198 buf->topbucket = buf->topbucket_ev = buf->topbucket_odd
2199 = buf->totfree = buf->total = buf->total_chain = 0;
2201 buf->minbucket = MIN_BUCKET;
2203 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
2204 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
2208 buf->ntotal[i] = nmalloc[i];
2210 buf->totfree += j * BUCKET_SIZE_REAL(i);
2211 buf->total += nmalloc[i] * BUCKET_SIZE_REAL(i);
2213 i % 2 ? (buf->topbucket_odd = i) : (buf->topbucket_ev = i);
2217 nextchain = chunk_chain;
2219 buf->total_chain += nextchain->size;
2220 nextchain = nextchain->next;
2222 buf->total_sbrk = goodsbrk + sbrk_slack;
2224 buf->sbrk_good = sbrk_goodness;
2225 buf->sbrk_slack = sbrk_slack;
2226 buf->start_slack = start_slack;
2227 buf->sbrked_remains = sbrked_remains;
2229 buf->nbuckets = NBUCKETS;
2231 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
2234 buf->bucket_mem_size[i] = BUCKET_SIZE_NO_SURPLUS(i);
2235 buf->bucket_available_size[i] = BUCKET_SIZE_REAL(i);
2238 #else /* defined DEBUGGING_MSTATS */
2239 PerlIO_printf(Perl_error_log, "perl not compiled with DEBUGGING_MSTATS\n");
2240 #endif /* defined DEBUGGING_MSTATS */
2241 return 0; /* XXX unused */
2245 =for apidoc dump_mstats
2247 When enabled by compiling with C<-DDEBUGGING_MSTATS>, print out statistics
2248 about malloc as two lines of numbers, one showing the length of the free list
2249 for each size category, the second showing the number of S<mallocs - frees> for
2252 C<s>, if not NULL, is used as a phrase to include in the output, such as
2253 S<"after compilation">.
2259 Perl_dump_mstats(pTHX_ const char *s)
2261 #ifdef DEBUGGING_MSTATS
2263 perl_mstats_t buffer;
2267 PERL_ARGS_ASSERT_DUMP_MSTATS;
2271 get_mstats(&buffer, NBUCKETS, 0);
2274 PerlIO_printf(Perl_error_log,
2275 "Memory allocation statistics %s (buckets %" IVdf
2276 "(%" IVdf ")..%" IVdf "(%" IVdf ")\n",
2278 (IV)BUCKET_SIZE_REAL(MIN_BUCKET),
2279 (IV)BUCKET_SIZE_NO_SURPLUS(MIN_BUCKET),
2280 (IV)BUCKET_SIZE_REAL(buffer.topbucket),
2281 (IV)BUCKET_SIZE_NO_SURPLUS(buffer.topbucket));
2282 PerlIO_printf(Perl_error_log, "%8" IVdf " free:", buffer.totfree);
2283 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
2284 PerlIO_printf(Perl_error_log,
2285 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2287 : ((i < 12*BUCKETS_PER_POW2) ? " %3" UVuf
2291 #ifdef BUCKETS_ROOT2
2292 PerlIO_printf(Perl_error_log, "\n\t ");
2293 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
2294 PerlIO_printf(Perl_error_log,
2295 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2297 : ((i < 12*BUCKETS_PER_POW2) ? " %3"UVuf : " %"UVuf)),
2301 PerlIO_printf(Perl_error_log, "\n%8" IVdf " used:",
2302 buffer.total - buffer.totfree);
2303 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
2304 PerlIO_printf(Perl_error_log,
2305 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2307 : ((i < 12*BUCKETS_PER_POW2) ? " %3" IVdf : " %" IVdf)),
2308 buffer.ntotal[i] - buffer.nfree[i]);
2310 #ifdef BUCKETS_ROOT2
2311 PerlIO_printf(Perl_error_log, "\n\t ");
2312 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
2313 PerlIO_printf(Perl_error_log,
2314 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2316 : ((i < 12*BUCKETS_PER_POW2) ? " %3"IVdf : " %"IVdf)),
2317 buffer.ntotal[i] - buffer.nfree[i]);
2320 PerlIO_printf(Perl_error_log, "\nTotal sbrk(): %" IVdf "/%" IVdf ":%"
2321 IVdf ". Odd ends: pad+heads+chain+tail: %" IVdf "+%"
2322 IVdf "+%" IVdf "+%" IVdf ".\n",
2323 buffer.total_sbrk, buffer.sbrks, buffer.sbrk_good,
2324 buffer.sbrk_slack, buffer.start_slack,
2325 buffer.total_chain, buffer.sbrked_remains);
2326 #else /* DEBUGGING_MSTATS */
2327 PerlIO_printf(Perl_error_log, "%s: perl not compiled with DEBUGGING_MSTATS\n",s);
2328 #endif /* DEBUGGING_MSTATS */
2331 #ifdef USE_PERL_SBRK
2333 # if defined(PURIFY)
2334 # define PERL_SBRK_VIA_MALLOC
2337 # ifdef PERL_SBRK_VIA_MALLOC
2339 /* it may seem schizophrenic to use perl's malloc and let it call system */
2340 /* malloc, the reason for that is only the 3.2 version of the OS that had */
2341 /* frequent core dumps within nxzonefreenolock. This sbrk routine put an */
2342 /* end to the cores */
2344 # ifndef SYSTEM_ALLOC
2345 # define SYSTEM_ALLOC(a) malloc(a)
2347 # ifndef SYSTEM_ALLOC_ALIGNMENT
2348 # define SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES
2351 # endif /* PERL_SBRK_VIA_MALLOC */
2353 static IV Perl_sbrk_oldchunk;
2354 static long Perl_sbrk_oldsize;
2356 # define PERLSBRK_32_K (1<<15)
2357 # define PERLSBRK_64_K (1<<16)
2365 if (!size) return 0;
2366 reqsize = size; /* just for the DEBUG_m statement */
2368 size = (size + 0x7ff) & ~0x7ff;
2370 if (size <= Perl_sbrk_oldsize) {
2371 got = Perl_sbrk_oldchunk;
2372 Perl_sbrk_oldchunk += size;
2373 Perl_sbrk_oldsize -= size;
2375 if (size >= PERLSBRK_32_K) {
2378 size = PERLSBRK_64_K;
2381 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2382 size += NEEDED_ALIGNMENT - SYSTEM_ALLOC_ALIGNMENT;
2384 got = (IV)SYSTEM_ALLOC(size);
2385 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2386 got = (got + NEEDED_ALIGNMENT - 1) & ~(NEEDED_ALIGNMENT - 1);
2389 /* Chunk is small, register the rest for future allocs. */
2390 Perl_sbrk_oldchunk = got + reqsize;
2391 Perl_sbrk_oldsize = size - reqsize;
2395 DEBUG_m(PerlIO_printf(Perl_debug_log,
2396 "sbrk malloc size %ld (reqsize %ld), left size %ld, give addr 0x%"
2398 size, reqsize, Perl_sbrk_oldsize, PTR2UV(got)));
2403 #endif /* ! defined USE_PERL_SBRK */
2406 * ex: set ts=8 sts=4 sw=4 et: