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 croak Perl_croak_nocontext
243 # define croak2 Perl_croak_nocontext
244 # define warn Perl_warn_nocontext
245 # define warn2 Perl_warn_nocontext
247 # define croak2 croak
251 # define PERL_MAYBE_ALIVE PL_thr_key
253 # define PERL_MAYBE_ALIVE 1
257 # error "MYMALLOC is not defined"
261 # define MUTEX_LOCK(l)
265 # define MUTEX_UNLOCK(l)
269 # define MALLOC_LOCK MUTEX_LOCK(&PL_malloc_mutex)
272 #ifndef MALLOC_UNLOCK
273 # define MALLOC_UNLOCK MUTEX_UNLOCK(&PL_malloc_mutex)
276 # ifndef fatalcroak /* make depend */
277 # define fatalcroak(mess) (write(2, (mess), strlen(mess)), exit(2))
282 # define DEBUG_m(a) \
284 if (PERL_MAYBE_ALIVE && PERL_GET_THX) { \
286 if (DEBUG_m_TEST) { \
287 PL_debug &= ~DEBUG_m_FLAG; \
289 PL_debug |= DEBUG_m_FLAG; \
296 # define PERL_IS_ALIVE aTHX
298 # define PERL_IS_ALIVE TRUE
305 * The memory is broken into "blocks" which occupy multiples of 2K (and
306 * generally speaking, have size "close" to a power of 2). The addresses
307 * of such *unused* blocks are kept in nextf[i] with big enough i. (nextf
308 * is an array of linked lists.) (Addresses of used blocks are not known.)
310 * Moreover, since the algorithm may try to "bite" smaller blocks out
311 * of unused bigger ones, there are also regions of "irregular" size,
312 * managed separately, by a linked list chunk_chain.
314 * The third type of storage is the sbrk()ed-but-not-yet-used space, its
315 * end and size are kept in last_sbrk_top and sbrked_remains.
317 * Growing blocks "in place":
318 * ~~~~~~~~~~~~~~~~~~~~~~~~~
319 * The address of the block with the greatest address is kept in last_op
320 * (if not known, last_op is 0). If it is known that the memory above
321 * last_op is not continuous, or contains a chunk from chunk_chain,
322 * last_op is set to 0.
324 * The chunk with address last_op may be grown by expanding into
325 * sbrk()ed-but-not-yet-used space, or trying to sbrk() more continuous
328 * Management of last_op:
329 * ~~~~~~~~~~~~~~~~~~~~~
331 * free() never changes the boundaries of blocks, so is not relevant.
333 * The only way realloc() may change the boundaries of blocks is if it
334 * grows a block "in place". However, in the case of success such a
335 * chunk is automatically last_op, and it remains last_op. In the case
336 * of failure getpages_adjacent() clears last_op.
338 * malloc() may change blocks by calling morecore() only.
340 * morecore() may create new blocks by:
341 * a) biting pieces from chunk_chain (cannot create one above last_op);
342 * b) biting a piece from an unused block (if block was last_op, this
343 * may create a chunk from chain above last_op, thus last_op is
344 * invalidated in such a case).
345 * c) biting of sbrk()ed-but-not-yet-used space. This creates
346 * a block which is last_op.
347 * d) Allocating new pages by calling getpages();
349 * getpages() creates a new block. It marks last_op at the bottom of
350 * the chunk of memory it returns.
352 * Active pages footprint:
353 * ~~~~~~~~~~~~~~~~~~~~~~
354 * Note that we do not need to traverse the lists in nextf[i], just take
355 * the first element of this list. However, we *need* to traverse the
356 * list in chunk_chain, but most the time it should be a very short one,
357 * so we do not step on a lot of pages we are not going to use.
361 * get_from_bigger_buckets(): forget to increment price => Quite
365 /* I don't much care whether these are defined in sys/types.h--LAW */
367 #define u_char unsigned char
368 #define u_int unsigned int
370 * I removed the definition of u_bigint which appeared to be u_bigint = UV
371 * u_bigint was only used in TWOK_MASKED and TWOK_SHIFT
372 * where I have used PTR2UV. RMB
374 #define u_short unsigned short
376 #if defined(RCHECK) && defined(PACK_MALLOC)
381 * The description below is applicable if PACK_MALLOC is not defined.
383 * The overhead on a block is at least 4 bytes. When free, this space
384 * contains a pointer to the next free block, and the bottom two bits must
385 * be zero. When in use, the first byte is set to MAGIC, and the second
386 * byte is the size index. The remaining bytes are for alignment.
387 * If range checking is enabled and the size of the block fits
388 * in two bytes, then the top two bytes hold the size of the requested block
389 * plus the range checking words, and the header word MINUS ONE.
392 union overhead *ov_next; /* when free */
393 #if MEM_ALIGNBYTES > 4
394 double strut; /* alignment problems */
395 # if MEM_ALIGNBYTES > 8
396 char sstrut[MEM_ALIGNBYTES]; /* for the sizing */
401 * Keep the ovu_index and ovu_magic in this order, having a char
402 * field first gives alignment indigestion in some systems, such as
405 u_char ovu_index; /* bucket # */
406 u_char ovu_magic; /* magic number */
408 /* Subtract one to fit into u_short for an extra bucket */
409 u_short ovu_size; /* block size (requested + overhead - 1) */
410 u_int ovu_rmagic; /* range magic number */
413 #define ov_magic ovu.ovu_magic
414 #define ov_index ovu.ovu_index
415 #define ov_size ovu.ovu_size
416 #define ov_rmagic ovu.ovu_rmagic
419 #define MAGIC 0xff /* magic # on accounting info */
420 #define RMAGIC 0x55555555 /* magic # on range info */
421 #define RMAGIC_C 0x55 /* magic # on range info */
424 # define RMAGIC_SZ sizeof (u_int) /* Overhead at end of bucket */
425 # ifdef TWO_POT_OPTIMIZE
426 # define MAX_SHORT_BUCKET (12 * BUCKETS_PER_POW2) /* size-1 fits in short */
428 # define MAX_SHORT_BUCKET (13 * BUCKETS_PER_POW2)
434 #if !defined(PACK_MALLOC) && defined(BUCKETS_ROOT2)
435 # undef BUCKETS_ROOT2
439 # define BUCKET_TABLE_SHIFT 2
440 # define BUCKET_POW2_SHIFT 1
441 # define BUCKETS_PER_POW2 2
443 # define BUCKET_TABLE_SHIFT MIN_BUC_POW2
444 # define BUCKET_POW2_SHIFT 0
445 # define BUCKETS_PER_POW2 1
448 #if !defined(MEM_ALIGNBYTES) || ((MEM_ALIGNBYTES > 4) && !defined(STRICT_ALIGNMENT))
449 /* Figure out the alignment of void*. */
454 # define ALIGN_SMALL ((IV)((caddr_t)&(((struct aligner*)0)->p)))
456 # define ALIGN_SMALL MEM_ALIGNBYTES
459 #define IF_ALIGN_8(yes,no) ((ALIGN_SMALL>4) ? (yes) : (no))
462 # define MAX_BUCKET_BY_TABLE 13
463 static const u_short buck_size[MAX_BUCKET_BY_TABLE + 1] =
465 0, 0, 0, 0, 4, 4, 8, 12, 16, 24, 32, 48, 64, 80,
467 # define BUCKET_SIZE_NO_SURPLUS(i) ((i) % 2 ? buck_size[i] : (1 << ((i) >> BUCKET_POW2_SHIFT)))
468 # define BUCKET_SIZE_REAL(i) ((i) <= MAX_BUCKET_BY_TABLE \
469 ? ((size_t)buck_size[i]) \
470 : ((((size_t)1) << ((i) >> BUCKET_POW2_SHIFT)) \
472 + POW2_OPTIMIZE_SURPLUS(i)))
474 # define BUCKET_SIZE_NO_SURPLUS(i) (((size_t)1) << ((i) >> BUCKET_POW2_SHIFT))
475 # define BUCKET_SIZE(i) (BUCKET_SIZE_NO_SURPLUS(i) + POW2_OPTIMIZE_SURPLUS(i))
476 # define BUCKET_SIZE_REAL(i) (BUCKET_SIZE(i) - MEM_OVERHEAD(i))
481 /* In this case there are several possible layout of arenas depending
482 * on the size. Arenas are of sizes multiple to 2K, 2K-aligned, and
483 * have a size close to a power of 2.
485 * Arenas of the size >= 4K keep one chunk only. Arenas of size 2K
486 * may keep one chunk or multiple chunks. Here are the possible
489 * # One chunk only, chunksize 2^k + SOMETHING - ALIGN, k >= 11
491 * INDEX MAGIC1 UNUSED CHUNK1
493 * # Multichunk with sanity checking and chunksize 2^k-ALIGN, k>7
495 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 CHUNK2 CHUNK3 ...
497 * # Multichunk with sanity checking and size 2^k-ALIGN, k=7
499 * INDEX MAGIC1 MAGIC2 MAGIC3 UNUSED CHUNK1 UNUSED CHUNK2 CHUNK3 ...
501 * # Multichunk with sanity checking and size up to 80
503 * INDEX UNUSED MAGIC1 UNUSED MAGIC2 UNUSED ... CHUNK1 CHUNK2 CHUNK3 ...
505 * # No sanity check (usually up to 48=byte-long buckets)
506 * INDEX UNUSED CHUNK1 CHUNK2 ...
508 * Above INDEX and MAGIC are one-byte-long. Sizes of UNUSED are
509 * appropriate to keep algorithms simple and memory aligned. INDEX
510 * encodes the size of the chunk, while MAGICn encodes state (used,
511 * free or non-managed-by-us-so-it-indicates-a-bug) of CHUNKn. MAGIC
512 * is used for sanity checking purposes only. SOMETHING is 0 or 4K
513 * (to make size of big CHUNK accommodate allocations for powers of two
516 * [There is no need to alignment between chunks, since C rules ensure
517 * that structs which need 2^k alignment have sizeof which is
518 * divisible by 2^k. Thus as far as the last chunk is aligned at the
519 * end of the arena, and 2K-alignment does not contradict things,
520 * everything is going to be OK for sizes of chunks 2^n and 2^n +
521 * 2^k. Say, 80-bit buckets will be 16-bit aligned, and as far as we
522 * put allocations for requests in 65..80 range, all is fine.
524 * Note, however, that standard malloc() puts more strict
525 * requirements than the above C rules. Moreover, our algorithms of
526 * realloc() may break this idyll, but we suppose that realloc() does
527 * need not change alignment.]
529 * Is very important to make calculation of the offset of MAGICm as
530 * quick as possible, since it is done on each malloc()/free(). In
531 * fact it is so quick that it has quite little effect on the speed of
532 * doing malloc()/free(). [By default] We forego such calculations
533 * for small chunks, but only to save extra 3% of memory, not because
534 * of speed considerations.
536 * Here is the algorithm [which is the same for all the allocations
537 * schemes above], see OV_MAGIC(block,bucket). Let OFFSETm be the
538 * offset of the CHUNKm from the start of ARENA. Then offset of
539 * MAGICm is (OFFSET1 >> SHIFT) + ADDOFFSET. Here SHIFT and ADDOFFSET
540 * are numbers which depend on the size of the chunks only.
542 * Let as check some sanity conditions. Numbers OFFSETm>>SHIFT are
543 * different for all the chunks in the arena if 2^SHIFT is not greater
544 * than size of the chunks in the arena. MAGIC1 will not overwrite
545 * INDEX provided ADDOFFSET is >0 if OFFSET1 < 2^SHIFT. MAGIClast
546 * will not overwrite CHUNK1 if OFFSET1 > (OFFSETlast >> SHIFT) +
549 * Make SHIFT the maximal possible (there is no point in making it
550 * smaller). Since OFFSETlast is 2K - CHUNKSIZE, above restrictions
551 * give restrictions on OFFSET1 and on ADDOFFSET.
553 * In particular, for chunks of size 2^k with k>=6 we can put
554 * ADDOFFSET to be from 0 to 2^k - 2^(11-k), and have
555 * OFFSET1==chunksize. For chunks of size 80 OFFSET1 of 2K%80=48 is
556 * large enough to have ADDOFFSET between 1 and 16 (similarly for 96,
557 * when ADDOFFSET should be 1). In particular, keeping MAGICs for
558 * these sizes gives no additional size penalty.
560 * However, for chunks of size 2^k with k<=5 this gives OFFSET1 >=
561 * ADDOFSET + 2^(11-k). Keeping ADDOFFSET 0 allows for 2^(11-k)-2^(11-2k)
562 * chunks per arena. This is smaller than 2^(11-k) - 1 which are
563 * needed if no MAGIC is kept. [In fact, having a negative ADDOFFSET
564 * would allow for slightly more buckets per arena for k=2,3.]
566 * Similarly, for chunks of size 3/2*2^k with k<=5 MAGICs would span
567 * the area up to 2^(11-k)+ADDOFFSET. For k=4 this give optimal
568 * ADDOFFSET as -7..0. For k=3 ADDOFFSET can go up to 4 (with tiny
569 * savings for negative ADDOFFSET). For k=5 ADDOFFSET can go -1..16
570 * (with no savings for negative values).
572 * In particular, keeping ADDOFFSET 0 for sizes of chunks up to 2^6
573 * leads to tiny pessimizations in case of sizes 4, 8, 12, 24, and
574 * leads to no contradictions except for size=80 (or 96.)
576 * However, it also makes sense to keep no magic for sizes 48 or less.
577 * This is what we do. In this case one needs ADDOFFSET>=1 also for
578 * chunksizes 12, 24, and 48, unless one gets one less chunk per
581 * The algo of OV_MAGIC(block,bucket) keeps ADDOFFSET 0 until
582 * chunksize of 64, then makes it 1.
584 * This allows for an additional optimization: the above scheme leads
585 * to giant overheads for sizes 128 or more (one whole chunk needs to
586 * be sacrifised to keep INDEX). Instead we use chunks not of size
587 * 2^k, but of size 2^k-ALIGN. If we pack these chunks at the end of
588 * the arena, then the beginnings are still in different 2^k-long
589 * sections of the arena if k>=7 for ALIGN==4, and k>=8 if ALIGN=8.
590 * Thus for k>7 the above algo of calculating the offset of the magic
591 * will still give different answers for different chunks. And to
592 * avoid the overrun of MAGIC1 into INDEX, one needs ADDOFFSET of >=1.
593 * In the case k=7 we just move the first chunk an extra ALIGN
594 * backward inside the ARENA (this is done once per arena lifetime,
595 * thus is not a big overhead). */
596 # define MAX_PACKED_POW2 6
597 # define MAX_PACKED (MAX_PACKED_POW2 * BUCKETS_PER_POW2 + BUCKET_POW2_SHIFT)
598 # define MAX_POW2_ALGO ((1<<(MAX_PACKED_POW2 + 1)) - M_OVERHEAD)
599 # define TWOK_MASK nBIT_MASK(LOG_OF_MIN_ARENA)
600 # define TWOK_MASKED(x) (PTR2UV(x) & ~TWOK_MASK)
601 # define TWOK_SHIFT(x) (PTR2UV(x) & TWOK_MASK)
602 # define OV_INDEXp(block) (INT2PTR(u_char*,TWOK_MASKED(block)))
603 # define OV_INDEX(block) (*OV_INDEXp(block))
604 # define OV_MAGIC(block,bucket) (*(OV_INDEXp(block) + \
605 (TWOK_SHIFT(block)>> \
606 (bucket>>BUCKET_POW2_SHIFT)) + \
607 (bucket >= MIN_NEEDS_SHIFT ? 1 : 0)))
608 /* A bucket can have a shift smaller than it size, we need to
609 shift its magic number so it will not overwrite index: */
610 # ifdef BUCKETS_ROOT2
611 # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2 - 1) /* Shift 80 greater than chunk 64. */
613 # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2) /* Shift 128 greater than chunk 32. */
615 # define CHUNK_SHIFT 0
617 /* Number of active buckets of given ordinal. */
618 #ifdef IGNORE_SMALL_BAD_FREE
619 #define FIRST_BUCKET_WITH_CHECK (6 * BUCKETS_PER_POW2) /* 64 */
620 # define N_BLKS(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \
621 ? nBIT_MASK(LOG_OF_MIN_ARENA)/BUCKET_SIZE_NO_SURPLUS(bucket) \
624 # define N_BLKS(bucket) n_blks[bucket]
627 static const u_short n_blks[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
629 # if BUCKETS_PER_POW2==1
631 (MIN_BUC_POW2==2 ? 384 : 0),
632 224, 120, 62, 31, 16, 8, 4, 2
635 (MIN_BUC_POW2==2 ? 384 : 0), (MIN_BUC_POW2==2 ? 384 : 0), /* 4, 4 */
636 224, 149, 120, 80, 62, 41, 31, 25, 16, 16, 8, 8, 4, 4, 2, 2
640 /* Shift of the first bucket with the given ordinal inside 2K chunk. */
641 #ifdef IGNORE_SMALL_BAD_FREE
642 # define BLK_SHIFT(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \
643 ? ((1<<LOG_OF_MIN_ARENA) \
644 - BUCKET_SIZE_NO_SURPLUS(bucket) * N_BLKS(bucket)) \
647 # define BLK_SHIFT(bucket) blk_shift[bucket]
650 static const u_short blk_shift[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] =
652 # if BUCKETS_PER_POW2==1
654 (MIN_BUC_POW2==2 ? 512 : 0),
655 256, 128, 64, 64, /* 8 to 64 */
656 16*sizeof(union overhead),
657 8*sizeof(union overhead),
658 4*sizeof(union overhead),
659 2*sizeof(union overhead),
662 (MIN_BUC_POW2==2 ? 512 : 0), (MIN_BUC_POW2==2 ? 512 : 0),
663 256, 260, 128, 128, 64, 80, 64, 48, /* 8 to 96 */
664 16*sizeof(union overhead), 16*sizeof(union overhead),
665 8*sizeof(union overhead), 8*sizeof(union overhead),
666 4*sizeof(union overhead), 4*sizeof(union overhead),
667 2*sizeof(union overhead), 2*sizeof(union overhead),
671 # define NEEDED_ALIGNMENT 0x800 /* 2k boundaries */
672 # define WANTED_ALIGNMENT 0x800 /* 2k boundaries */
674 #else /* !PACK_MALLOC */
676 # define OV_MAGIC(block,bucket) (block)->ov_magic
677 # define OV_INDEX(block) (block)->ov_index
678 # define CHUNK_SHIFT 1
679 # define MAX_PACKED -1
680 # define NEEDED_ALIGNMENT MEM_ALIGNBYTES
681 # define WANTED_ALIGNMENT 0x400 /* 1k boundaries */
683 #endif /* !PACK_MALLOC */
685 #define M_OVERHEAD (sizeof(union overhead) + RMAGIC_SZ) /* overhead at start+end */
688 # define MEM_OVERHEAD(bucket) \
689 (bucket <= MAX_PACKED ? ((size_t)0) : M_OVERHEAD)
690 # ifdef SMALL_BUCKET_VIA_TABLE
691 # define START_SHIFTS_BUCKET ((MAX_PACKED_POW2 + 1) * BUCKETS_PER_POW2)
692 # define START_SHIFT MAX_PACKED_POW2
693 # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */
694 # define SIZE_TABLE_MAX 80
696 # define SIZE_TABLE_MAX 64
698 static const char bucket_of[] =
700 # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */
701 /* 0 to 15 in 4-byte increments. */
702 (sizeof(void*) > 4 ? 6 : 5), /* 4/8, 5-th bucket for better reports */
704 IF_ALIGN_8(8,7), 8, /* 16/12, 16 */
705 9, 9, 10, 10, /* 24, 32 */
706 11, 11, 11, 11, /* 48 */
707 12, 12, 12, 12, /* 64 */
708 13, 13, 13, 13, /* 80 */
709 13, 13, 13, 13 /* 80 */
710 # else /* !BUCKETS_ROOT2 */
711 /* 0 to 15 in 4-byte increments. */
712 (sizeof(void*) > 4 ? 3 : 2),
718 # endif /* !BUCKETS_ROOT2 */
720 # else /* !SMALL_BUCKET_VIA_TABLE */
721 # define START_SHIFTS_BUCKET MIN_BUCKET
722 # define START_SHIFT (MIN_BUC_POW2 - 1)
723 # endif /* !SMALL_BUCKET_VIA_TABLE */
724 #else /* !PACK_MALLOC */
725 # define MEM_OVERHEAD(bucket) M_OVERHEAD
726 # ifdef SMALL_BUCKET_VIA_TABLE
727 # undef SMALL_BUCKET_VIA_TABLE
729 # define START_SHIFTS_BUCKET MIN_BUCKET
730 # define START_SHIFT (MIN_BUC_POW2 - 1)
731 #endif /* !PACK_MALLOC */
734 * Big allocations are often of the size 2^n bytes. To make them a
735 * little bit better, make blocks of size 2^n+pagesize for big n.
738 #ifdef TWO_POT_OPTIMIZE
740 # ifndef PERL_PAGESIZE
741 # define PERL_PAGESIZE 4096
743 # ifndef FIRST_BIG_POW2
744 # define FIRST_BIG_POW2 15 /* 32K, 16K is used too often. */
746 # define FIRST_BIG_BLOCK (1<<FIRST_BIG_POW2)
747 /* If this value or more, check against bigger blocks. */
748 # define FIRST_BIG_BOUND (FIRST_BIG_BLOCK - M_OVERHEAD)
749 /* If less than this value, goes into 2^n-overhead-block. */
750 # define LAST_SMALL_BOUND ((FIRST_BIG_BLOCK>>1) - M_OVERHEAD)
752 # define POW2_OPTIMIZE_ADJUST(nbytes) \
753 ((nbytes >= FIRST_BIG_BOUND) ? nbytes -= PERL_PAGESIZE : 0)
754 # define POW2_OPTIMIZE_SURPLUS(bucket) \
755 ((size_t)((bucket >= FIRST_BIG_POW2 * BUCKETS_PER_POW2) ? PERL_PAGESIZE : 0))
757 #else /* !TWO_POT_OPTIMIZE */
758 # define POW2_OPTIMIZE_ADJUST(nbytes)
759 # define POW2_OPTIMIZE_SURPLUS(bucket) ((size_t)0)
760 #endif /* !TWO_POT_OPTIMIZE */
762 #define BARK_64K_LIMIT(what,nbytes,size)
765 # define MIN_SBRK 2048
769 # define FIRST_SBRK (48*1024)
772 /* Minimal sbrk in percents of what is already alloced. */
773 #ifndef MIN_SBRK_FRAC
774 # define MIN_SBRK_FRAC 3
777 #ifndef SBRK_ALLOW_FAILURES
778 # define SBRK_ALLOW_FAILURES 3
781 #ifndef SBRK_FAILURE_PRICE
782 # define SBRK_FAILURE_PRICE 50
785 static void morecore (int bucket);
786 # if defined(DEBUGGING)
787 static void botch (const char *diag, const char *s, const char *file, int line);
789 static void add_to_chain (void *p, MEM_SIZE size, MEM_SIZE chip);
790 static void* get_from_chain (MEM_SIZE size);
791 static void* get_from_bigger_buckets(int bucket, MEM_SIZE size);
792 static union overhead *getpages (MEM_SIZE needed, int *nblksp, int bucket);
793 static int getpages_adjacent(MEM_SIZE require);
795 #ifdef I_MACH_CTHREADS
797 # define MUTEX_LOCK(m) STMT_START { if (*m) mutex_lock(*m); } STMT_END
799 # define MUTEX_UNLOCK(m) STMT_START { if (*m) mutex_unlock(*m); } STMT_END
803 # define PTRSIZE sizeof(void*)
807 # define BITS_IN_PTR (8*PTRSIZE)
811 * nextf[i] is the pointer to the next free block of size 2^i. The
812 * smallest allocatable block is 8 bytes. The overhead information
813 * precedes the data area returned to the user.
815 #define NBUCKETS (BITS_IN_PTR*BUCKETS_PER_POW2 + 1)
816 static union overhead *nextf[NBUCKETS];
818 #if defined(PURIFY) && !defined(USE_PERL_SBRK)
819 # define USE_PERL_SBRK
823 # define sbrk(a) Perl_sbrk(a)
824 Malloc_t Perl_sbrk (int size);
825 #elif !defined(HAS_SBRK_PROTO) /* <unistd.h> usually takes care of this */
826 extern Malloc_t sbrk(int);
829 #ifndef MIN_SBRK_FRAC1000 /* Backward compatibility */
830 # define MIN_SBRK_FRAC1000 (MIN_SBRK_FRAC * 10)
833 #include "malloc_ctl.h"
835 #ifndef NO_MALLOC_DYNAMIC_CFG
836 # define PERL_MALLOC_OPT_CHARS "FMfAPGdac"
838 # ifndef FILL_DEAD_DEFAULT
839 # define FILL_DEAD_DEFAULT 1
841 # ifndef FILL_ALIVE_DEFAULT
842 # define FILL_ALIVE_DEFAULT 1
844 # ifndef FILL_CHECK_DEFAULT
845 # define FILL_CHECK_DEFAULT 1
848 static IV MallocCfg[MallocCfg_last] = {
854 SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE, /* sbrk_goodness */
855 FILL_DEAD_DEFAULT, /* FILL_DEAD */
856 FILL_ALIVE_DEFAULT, /* FILL_ALIVE */
857 FILL_CHECK_DEFAULT, /* FILL_CHECK */
858 0, /* MallocCfg_skip_cfg_env */
859 0, /* MallocCfg_cfg_env_read */
860 0, /* MallocCfg_emergency_buffer_size */
861 0, /* MallocCfg_emergency_buffer_prepared_size */
862 0 /* MallocCfg_emergency_buffer_last_req */
864 IV *MallocCfg_ptr = MallocCfg;
866 static char* MallocCfgP[MallocCfg_last] = {
867 0, /* MallocCfgP_emergency_buffer */
868 0, /* MallocCfgP_emergency_buffer_prepared */
870 char **MallocCfgP_ptr = MallocCfgP;
874 # undef MIN_SBRK_FRAC1000
875 # undef SBRK_ALLOW_FAILURES
876 # undef SBRK_FAILURE_PRICE
878 # define MIN_SBRK MallocCfg[MallocCfg_MIN_SBRK]
879 # define FIRST_SBRK MallocCfg[MallocCfg_FIRST_SBRK]
880 # define MIN_SBRK_FRAC1000 MallocCfg[MallocCfg_MIN_SBRK_FRAC1000]
881 # define SBRK_ALLOW_FAILURES MallocCfg[MallocCfg_SBRK_ALLOW_FAILURES]
882 # define SBRK_FAILURE_PRICE MallocCfg[MallocCfg_SBRK_FAILURE_PRICE]
884 # define sbrk_goodness MallocCfg[MallocCfg_sbrk_goodness]
886 # define emergency_buffer_size MallocCfg[MallocCfg_emergency_buffer_size]
887 # define emergency_buffer_last_req MallocCfg[MallocCfg_emergency_buffer_last_req]
889 # define FILL_DEAD MallocCfg[MallocCfg_filldead]
890 # define FILL_ALIVE MallocCfg[MallocCfg_fillalive]
891 # define FILL_CHECK_CFG MallocCfg[MallocCfg_fillcheck]
892 # define FILL_CHECK (FILL_DEAD && FILL_CHECK_CFG)
894 # define emergency_buffer MallocCfgP[MallocCfgP_emergency_buffer]
895 # define emergency_buffer_prepared MallocCfgP[MallocCfgP_emergency_buffer_prepared]
897 #else /* defined(NO_MALLOC_DYNAMIC_CFG) */
900 # define FILL_ALIVE 1
901 # define FILL_CHECK 1
902 static int sbrk_goodness = SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE;
904 # define NO_PERL_MALLOC_ENV
908 #ifdef DEBUGGING_MSTATS
910 * nmalloc[i] is the difference between the number of mallocs and frees
911 * for a given block size.
913 static u_int nmalloc[NBUCKETS];
914 static u_int sbrk_slack;
915 static u_int start_slack;
916 #else /* !( defined DEBUGGING_MSTATS ) */
917 # define sbrk_slack 0
920 static u_int goodsbrk;
922 #ifdef PERL_EMERGENCY_SBRK
925 # define BIG_SIZE (1<<16) /* 64K */
928 # ifdef NO_MALLOC_DYNAMIC_CFG
929 static MEM_SIZE emergency_buffer_size;
930 /* 0 if the last request for more memory succeeded.
931 Otherwise the size of the failing request. */
932 static MEM_SIZE emergency_buffer_last_req;
933 static char *emergency_buffer;
934 static char *emergency_buffer_prepared;
937 # ifndef emergency_sbrk_croak
938 # define emergency_sbrk_croak croak2
942 perl_get_emergency_buffer(IV *size)
945 /* First offense, give a possibility to recover by dieing. */
946 /* No malloc involved here: */
949 GV **gvp = (GV**)hv_fetchs(PL_defstash, "^M", FALSE);
951 if (!gvp) gvp = (GV**)hv_fetchs(PL_defstash, "\015", FALSE);
952 if (!gvp || !(sv = GvSV(*gvp)) || !SvPOK(sv)
953 || (SvLEN(sv) < (1<<LOG_OF_MIN_ARENA) - M_OVERHEAD))
954 return NULL; /* Now die die die... */
955 /* Got it, now detach SvPV: */
957 /* Check alignment: */
958 if ((PTR2UV(pv) - sizeof(union overhead)) & (NEEDED_ALIGNMENT - 1)) {
959 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
960 return NULL; /* die die die */
967 *size = malloced_size(pv) + M_OVERHEAD;
968 return pv - sizeof(union overhead);
970 # define PERL_GET_EMERGENCY_BUFFER(p) perl_get_emergency_buffer(p)
972 # ifndef NO_MALLOC_DYNAMIC_CFG
974 get_emergency_buffer(IV *size)
976 char *pv = emergency_buffer_prepared;
978 *size = MallocCfg[MallocCfg_emergency_buffer_prepared_size];
979 emergency_buffer_prepared = 0;
980 MallocCfg[MallocCfg_emergency_buffer_prepared_size] = 0;
984 # define GET_EMERGENCY_BUFFER(p) get_emergency_buffer(p)
985 # else /* NO_MALLOC_DYNAMIC_CFG */
986 # define GET_EMERGENCY_BUFFER(p) NULL
990 emergency_sbrk(MEM_SIZE size)
992 MEM_SIZE rsize = (((size - 1)>>LOG_OF_MIN_ARENA) + 1)<<LOG_OF_MIN_ARENA;
995 && (!emergency_buffer_last_req ||
996 (size < (MEM_SIZE)emergency_buffer_last_req))) {
997 /* Give the possibility to recover, but avoid an infinite cycle. */
999 emergency_buffer_last_req = size;
1000 emergency_sbrk_croak("Out of memory during \"large\" request for %" UVuf
1001 " bytes, total sbrk() is %" UVuf " bytes",
1002 (UV)size, (UV)(goodsbrk + sbrk_slack));
1005 if ((MEM_SIZE)emergency_buffer_size >= rsize) {
1006 char *old = emergency_buffer;
1008 emergency_buffer_size -= rsize;
1009 emergency_buffer += rsize;
1012 /* First offense, give a possibility to recover by dieing. */
1013 /* No malloc involved here: */
1015 char *pv = GET_EMERGENCY_BUFFER(&Size);
1018 if (emergency_buffer_size) {
1019 add_to_chain(emergency_buffer, emergency_buffer_size, 0);
1020 emergency_buffer_size = 0;
1021 emergency_buffer = NULL;
1026 pv = PERL_GET_EMERGENCY_BUFFER(&Size);
1030 return (char *)-1; /* Now die die die... */
1033 /* Check alignment: */
1034 if (PTR2UV(pv) & (NEEDED_ALIGNMENT - 1)) {
1037 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
1038 return (char *)-1; /* die die die */
1041 emergency_buffer = pv;
1042 emergency_buffer_size = Size;
1046 emergency_sbrk_croak("Out of memory during request for %" UVuf
1047 " bytes, total sbrk() is %" UVuf " bytes",
1048 (UV)size, (UV)(goodsbrk + sbrk_slack));
1049 NOT_REACHED; /* NOTREACHED */
1053 #else /* !defined(PERL_EMERGENCY_SBRK) */
1054 # define emergency_sbrk(size) -1
1055 #endif /* defined PERL_EMERGENCY_SBRK */
1057 /* Don't use PerlIO buffered writes as they allocate memory. */
1058 #define MYMALLOC_WRITE2STDERR(s) PERL_UNUSED_RESULT(PerlLIO_write(PerlIO_fileno(PerlIO_stderr()),s,strlen(s)))
1062 #define ASSERT(p,diag) if (!(p)) botch(diag,STRINGIFY(p),__FILE__,__LINE__);
1065 botch(const char *diag, const char *s, const char *file, int line)
1068 if (!(PERL_MAYBE_ALIVE && PERL_GET_THX))
1071 if (PerlIO_printf(PerlIO_stderr(),
1072 "assertion botched (%s?): %s %s:%d\n",
1073 diag, s, file, line) != 0) {
1074 do_write: /* Can be initializing interpreter */
1075 MYMALLOC_WRITE2STDERR("assertion botched (");
1076 MYMALLOC_WRITE2STDERR(diag);
1077 MYMALLOC_WRITE2STDERR("?): ");
1078 MYMALLOC_WRITE2STDERR(s);
1079 MYMALLOC_WRITE2STDERR(" (");
1080 MYMALLOC_WRITE2STDERR(file);
1081 MYMALLOC_WRITE2STDERR(":");
1084 char *s = linebuf + sizeof(linebuf) - 1;
1088 *--s = '0' + (n % 10);
1090 MYMALLOC_WRITE2STDERR(s);
1092 MYMALLOC_WRITE2STDERR(")\n");
1098 #define ASSERT(p, diag)
1102 /* Fill should be long enough to cover long */
1104 fill_pat_4bytes(unsigned char *s, size_t nbytes, const unsigned char *fill)
1106 unsigned char *e = s + nbytes;
1108 const long lfill = *(long*)fill;
1110 if (PTR2UV(s) & (sizeof(long)-1)) { /* Align the pattern */
1111 int shift = sizeof(long) - (PTR2UV(s) & (sizeof(long)-1));
1112 unsigned const char *f = fill + sizeof(long) - shift;
1113 unsigned char *e1 = s + shift;
1119 while ((unsigned char*)(lp + 1) <= e)
1121 s = (unsigned char*)lp;
1125 /* Just malloc()ed */
1126 static const unsigned char fill_feedadad[] =
1127 {0xFE, 0xED, 0xAD, 0xAD, 0xFE, 0xED, 0xAD, 0xAD,
1128 0xFE, 0xED, 0xAD, 0xAD, 0xFE, 0xED, 0xAD, 0xAD};
1130 static const unsigned char fill_deadbeef[] =
1131 {0xDE, 0xAD, 0xBE, 0xEF, 0xDE, 0xAD, 0xBE, 0xEF,
1132 0xDE, 0xAD, 0xBE, 0xEF, 0xDE, 0xAD, 0xBE, 0xEF};
1133 # define FILL_DEADBEEF(s, n) \
1134 (void)(FILL_DEAD? (fill_pat_4bytes((s), (n), fill_deadbeef), 0) : 0)
1135 # define FILL_FEEDADAD(s, n) \
1136 (void)(FILL_ALIVE? (fill_pat_4bytes((s), (n), fill_feedadad), 0) : 0)
1138 # define FILL_DEADBEEF(s, n) ((void)0)
1139 # define FILL_FEEDADAD(s, n) ((void)0)
1140 # undef MALLOC_FILL_CHECK
1143 #ifdef MALLOC_FILL_CHECK
1145 cmp_pat_4bytes(unsigned char *s, size_t nbytes, const unsigned char *fill)
1147 unsigned char *e = s + nbytes;
1149 const long lfill = *(long*)fill;
1151 if (PTR2UV(s) & (sizeof(long)-1)) { /* Align the pattern */
1152 int shift = sizeof(long) - (PTR2UV(s) & (sizeof(long)-1));
1153 unsigned const char *f = fill + sizeof(long) - shift;
1154 unsigned char *e1 = s + shift;
1161 while ((unsigned char*)(lp + 1) <= e)
1164 s = (unsigned char*)lp;
1166 if (*s++ != *fill++)
1170 # define FILLCHECK_DEADBEEF(s, n) \
1171 ASSERT(!FILL_CHECK || !cmp_pat_4bytes(s, n, fill_deadbeef), \
1172 "free()ed/realloc()ed-away memory was overwritten")
1174 # define FILLCHECK_DEADBEEF(s, n) ((void)0)
1178 S_adjust_size_and_find_bucket(size_t *nbytes_p)
1184 PERL_ARGS_ASSERT_ADJUST_SIZE_AND_FIND_BUCKET;
1189 * Convert amount of memory requested into
1190 * closest block size stored in hash buckets
1191 * which satisfies request. Account for
1192 * space used per block for accounting.
1195 # ifdef SMALL_BUCKET_VIA_TABLE
1197 bucket = MIN_BUCKET;
1198 else if (nbytes <= SIZE_TABLE_MAX) {
1199 bucket = bucket_of[(nbytes - 1) >> BUCKET_TABLE_SHIFT];
1204 if (nbytes <= MAX_POW2_ALGO) goto do_shifts;
1209 POW2_OPTIMIZE_ADJUST(nbytes);
1210 nbytes += M_OVERHEAD;
1211 nbytes = (nbytes + 3) &~ 3;
1212 #if defined(PACK_MALLOC) && !defined(SMALL_BUCKET_VIA_TABLE)
1215 shiftr = (nbytes - 1) >> START_SHIFT;
1216 bucket = START_SHIFTS_BUCKET;
1217 /* apart from this loop, this is O(1) */
1218 while (shiftr >>= 1)
1219 bucket += BUCKETS_PER_POW2;
1228 Implements L<perlapi/C<Newx>> which you should use instead.
1234 Perl_malloc(size_t nbytes)
1238 #if defined(DEBUGGING) || defined(RCHECK)
1239 MEM_SIZE size = nbytes;
1242 /* A structure that has more than PTRDIFF_MAX bytes is unfortunately
1243 * legal in C, but in such, if two elements are far enough apart, we
1244 * can't legally find out how far apart they are. Limit the size of a
1245 * malloc so that pointer subtraction in the same structure is always
1247 if (nbytes > PTRDIFF_MAX) {
1249 MYMALLOC_WRITE2STDERR("Memory requests are limited to PTRDIFF_MAX"
1250 " bytes to prevent possible undefined"
1255 BARK_64K_LIMIT("Allocation",nbytes,nbytes);
1257 if ((long)nbytes < 0)
1258 croak("%s", "panic: malloc");
1261 bucket = adjust_size_and_find_bucket(&nbytes);
1264 * If nothing in hash bucket right now,
1265 * request more memory from the system.
1267 if (nextf[bucket] == NULL)
1269 if ((p = nextf[bucket]) == NULL) {
1274 #if defined(PLAIN_MALLOC) && defined(NO_FANCY_MALLOC)
1275 MYMALLOC_WRITE2STDERR("Out of memory!\n");
1278 char *eb = buff + sizeof(buff) - 1;
1282 MYMALLOC_WRITE2STDERR("Out of memory during request for ");
1283 #if defined(DEBUGGING) || defined(RCHECK)
1288 *--s = '0' + (n % 10);
1290 MYMALLOC_WRITE2STDERR(s);
1291 MYMALLOC_WRITE2STDERR(" bytes, total sbrk() is ");
1293 n = goodsbrk + sbrk_slack;
1295 *--s = '0' + (n % 10);
1297 MYMALLOC_WRITE2STDERR(s);
1298 MYMALLOC_WRITE2STDERR(" bytes!\n");
1299 #endif /* defined(PLAIN_MALLOC) && defined(NO_FANCY_MALLOC) */
1306 /* remove from linked list */
1308 if ( (PTR2UV(p) & (MEM_ALIGNBYTES - 1))
1309 /* Can't get this low */
1310 || (p && PTR2UV(p) < (1<<LOG_OF_MIN_ARENA)) ) {
1312 PerlIO_printf(PerlIO_stderr(),
1313 "Unaligned pointer in the free chain 0x%" UVxf "\n",
1316 if ( (PTR2UV(p->ov_next) & (MEM_ALIGNBYTES - 1))
1317 || (p->ov_next && PTR2UV(p->ov_next) < (1<<LOG_OF_MIN_ARENA)) ) {
1319 PerlIO_printf(PerlIO_stderr(),
1320 "Unaligned \"next\" pointer in the free "
1321 "chain 0x%" UVxf " at 0x%" UVxf "\n",
1322 PTR2UV(p->ov_next), PTR2UV(p));
1325 nextf[bucket] = p->ov_next;
1329 DEBUG_m(PerlIO_printf(Perl_debug_log,
1330 "%p: (%05lu) malloc %ld bytes\n",
1331 (Malloc_t)(p + CHUNK_SHIFT),
1332 (unsigned long)(PL_an++),
1335 FILLCHECK_DEADBEEF((unsigned char*)(p + CHUNK_SHIFT),
1336 BUCKET_SIZE_REAL(bucket) + RMAGIC_SZ);
1338 #ifdef IGNORE_SMALL_BAD_FREE
1339 if (bucket >= FIRST_BUCKET_WITH_CHECK)
1341 OV_MAGIC(p, bucket) = MAGIC;
1343 OV_INDEX(p) = bucket;
1347 * Record allocated size of block and
1348 * bound space with magic numbers.
1350 p->ov_rmagic = RMAGIC;
1351 if (bucket <= MAX_SHORT_BUCKET) {
1354 nbytes = size + M_OVERHEAD;
1355 p->ov_size = nbytes - 1;
1356 if ((i = nbytes & (RMAGIC_SZ-1))) {
1358 while (i--) /* nbytes - RMAGIC_SZ is end of alloced area */
1359 ((caddr_t)p + nbytes - RMAGIC_SZ)[i] = RMAGIC_C;
1361 /* Same at RMAGIC_SZ-aligned RMAGIC */
1362 nbytes = (nbytes + RMAGIC_SZ - 1) & ~(RMAGIC_SZ - 1);
1363 ((u_int *)((caddr_t)p + nbytes))[-1] = RMAGIC;
1365 FILL_FEEDADAD((unsigned char *)(p + CHUNK_SHIFT), size);
1367 return ((Malloc_t)(p + CHUNK_SHIFT));
1370 static char *last_sbrk_top;
1371 static char *last_op; /* This arena can be easily extended. */
1372 static MEM_SIZE sbrked_remains;
1374 #ifdef DEBUGGING_MSTATS
1378 struct chunk_chain_s {
1379 struct chunk_chain_s *next;
1382 static struct chunk_chain_s *chunk_chain;
1383 static int n_chunks;
1384 static char max_bucket;
1386 /* Cutoff a piece of one of the chunks in the chain. Prefer smaller chunk. */
1388 get_from_chain(MEM_SIZE size)
1390 struct chunk_chain_s *elt = chunk_chain, **oldp = &chunk_chain;
1391 struct chunk_chain_s **oldgoodp = NULL;
1392 long min_remain = LONG_MAX;
1395 if (elt->size >= size) {
1396 long remains = elt->size - size;
1397 if (remains >= 0 && remains < min_remain) {
1399 min_remain = remains;
1405 oldp = &( elt->next );
1408 if (!oldgoodp) return NULL;
1410 void *ret = *oldgoodp;
1411 struct chunk_chain_s *next = (*oldgoodp)->next;
1413 *oldgoodp = (struct chunk_chain_s *)((char*)ret + size);
1414 (*oldgoodp)->size = min_remain;
1415 (*oldgoodp)->next = next;
1418 void *ret = *oldgoodp;
1419 *oldgoodp = (*oldgoodp)->next;
1426 add_to_chain(void *p, MEM_SIZE size, MEM_SIZE chip)
1428 struct chunk_chain_s *next = chunk_chain;
1429 char *cp = (char*)p;
1432 chunk_chain = (struct chunk_chain_s *)cp;
1433 chunk_chain->size = size - chip;
1434 chunk_chain->next = next;
1439 get_from_bigger_buckets(int bucket, MEM_SIZE size)
1442 static int bucketprice[NBUCKETS];
1443 while (bucket <= max_bucket) {
1444 /* We postpone stealing from bigger buckets until we want it
1446 if (nextf[bucket] && bucketprice[bucket]++ >= price) {
1448 void *ret = (void*)(nextf[bucket] - 1 + CHUNK_SHIFT);
1449 bucketprice[bucket] = 0;
1450 if (((char*)nextf[bucket]) - M_OVERHEAD == last_op) {
1451 last_op = NULL; /* Disable optimization */
1453 nextf[bucket] = nextf[bucket]->ov_next;
1454 #ifdef DEBUGGING_MSTATS
1456 start_slack -= M_OVERHEAD;
1458 add_to_chain(ret, (BUCKET_SIZE_NO_SURPLUS(bucket) +
1459 POW2_OPTIMIZE_SURPLUS(bucket)),
1468 static union overhead *
1469 getpages(MEM_SIZE needed, int *nblksp, int bucket)
1471 /* Need to do (possibly expensive) system call. Try to
1472 optimize it for rare calling. */
1473 MEM_SIZE require = needed - sbrked_remains;
1475 union overhead *ovp;
1478 if (sbrk_goodness > 0) {
1479 if (!last_sbrk_top && require < (MEM_SIZE)FIRST_SBRK)
1480 require = FIRST_SBRK;
1481 else if (require < (MEM_SIZE)MIN_SBRK) require = MIN_SBRK;
1483 if (require < (Size_t)(goodsbrk * MIN_SBRK_FRAC1000 / 1000))
1484 require = goodsbrk * MIN_SBRK_FRAC1000 / 1000;
1485 require = ((require - 1 + MIN_SBRK) / MIN_SBRK) * MIN_SBRK;
1492 DEBUG_m(PerlIO_printf(Perl_debug_log,
1493 "sbrk(%ld) for %ld-byte-long arena\n",
1494 (long)require, (long) needed));
1495 cp = (char *)sbrk(require);
1496 #ifdef DEBUGGING_MSTATS
1499 if (cp == last_sbrk_top) {
1500 /* Common case, anything is fine. */
1502 ovp = (union overhead *) (cp - sbrked_remains);
1503 last_op = cp - sbrked_remains;
1504 sbrked_remains = require - (needed - sbrked_remains);
1505 } else if (cp == (char *)-1) { /* no more room! */
1506 ovp = (union overhead *)emergency_sbrk(needed);
1507 if (ovp == (union overhead *)-1)
1509 if (((char*)ovp) > last_op) { /* Cannot happen with current emergency_sbrk() */
1513 } else { /* Non-continuous or first sbrk(). */
1514 long add = sbrked_remains;
1517 if (sbrked_remains) { /* Put rest into chain, we
1518 cannot use it right now. */
1519 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1523 /* Second, check alignment. */
1526 /* WANTED_ALIGNMENT may be more than NEEDED_ALIGNMENT, but this may
1527 improve performance of memory access. */
1528 if (PTR2UV(cp) & (WANTED_ALIGNMENT - 1)) { /* Not aligned. */
1529 slack = WANTED_ALIGNMENT - (PTR2UV(cp) & (WANTED_ALIGNMENT - 1));
1534 DEBUG_m(PerlIO_printf(Perl_debug_log,
1535 "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",
1536 (long)add, (long) slack,
1537 (long) sbrked_remains));
1538 newcp = (char *)sbrk(add);
1539 #if defined(DEBUGGING_MSTATS)
1543 if (newcp != cp + require) {
1544 /* Too bad: even rounding sbrk() is not continuous.*/
1545 DEBUG_m(PerlIO_printf(Perl_debug_log,
1546 "failed to fix bad sbrk()\n"));
1550 fatalcroak("panic: Off-page sbrk\n");
1553 if (sbrked_remains) {
1555 #if defined(DEBUGGING_MSTATS)
1556 sbrk_slack += require;
1559 DEBUG_m(PerlIO_printf(Perl_debug_log,
1560 "straight sbrk(%ld)\n",
1562 cp = (char *)sbrk(require);
1563 #ifdef DEBUGGING_MSTATS
1566 if (cp == (char *)-1)
1569 sbrk_goodness = -1; /* Disable optimization!
1570 Continue with not-aligned... */
1573 require += sbrked_remains;
1577 if (last_sbrk_top) {
1578 sbrk_goodness -= SBRK_FAILURE_PRICE;
1581 ovp = (union overhead *) cp;
1583 * Round up to minimum allocation size boundary
1584 * and deduct from block count to reflect.
1587 # if NEEDED_ALIGNMENT > MEM_ALIGNBYTES
1588 if (PTR2UV(ovp) & (NEEDED_ALIGNMENT - 1))
1589 fatalcroak("Misalignment of sbrk()\n");
1592 if (PTR2UV(ovp) & (MEM_ALIGNBYTES - 1)) {
1593 DEBUG_m(PerlIO_printf(Perl_debug_log,
1594 "fixing sbrk(): %d bytes off machine alignment\n",
1595 (int)(PTR2UV(ovp) & (MEM_ALIGNBYTES - 1))));
1596 ovp = INT2PTR(union overhead *,(PTR2UV(ovp) + MEM_ALIGNBYTES) &
1597 (MEM_ALIGNBYTES - 1));
1599 # if defined(DEBUGGING_MSTATS)
1600 /* This is only approx. if TWO_POT_OPTIMIZE: */
1601 sbrk_slack += (1 << (bucket >> BUCKET_POW2_SHIFT));
1604 ; /* Finish "else" */
1605 sbrked_remains = require - needed;
1608 #if !defined(PLAIN_MALLOC) && !defined(NO_FANCY_MALLOC)
1609 emergency_buffer_last_req = 0;
1611 last_sbrk_top = cp + require;
1612 #ifdef DEBUGGING_MSTATS
1613 goodsbrk += require;
1619 getpages_adjacent(MEM_SIZE require)
1621 if (require <= sbrked_remains) {
1622 sbrked_remains -= require;
1626 require -= sbrked_remains;
1627 /* We do not try to optimize sbrks here, we go for place. */
1628 cp = (char*) sbrk(require);
1629 #ifdef DEBUGGING_MSTATS
1631 goodsbrk += require;
1633 if (cp == last_sbrk_top) {
1635 last_sbrk_top = cp + require;
1637 if (cp == (char*)-1) { /* Out of memory */
1638 #ifdef DEBUGGING_MSTATS
1639 goodsbrk -= require;
1643 /* Report the failure: */
1645 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1647 add_to_chain((void*)cp, require, 0);
1648 sbrk_goodness -= SBRK_FAILURE_PRICE;
1660 * Allocate more memory to the indicated bucket.
1663 morecore(int bucket)
1665 union overhead *ovp;
1666 int rnu; /* 2^rnu bytes will be requested */
1667 int nblks; /* become nblks blocks of the desired size */
1668 MEM_SIZE siz, needed;
1669 static int were_called = 0;
1673 #ifndef NO_PERL_MALLOC_ENV
1675 /* It's our first time. Initialize ourselves */
1676 were_called = 1; /* Avoid a loop */
1677 if (!MallocCfg[MallocCfg_skip_cfg_env]) {
1678 char *s = getenv("PERL_MALLOC_OPT"), *t = s;
1680 const char *opts = PERL_MALLOC_OPT_CHARS;
1683 while ( t && t[0] && t[1] == '='
1684 && ((off = strchr(opts, *t))) ) {
1689 val = 10*val + *t++ - '0';
1690 if (!*t || *t == ';') {
1691 if (MallocCfg[off - opts] != val)
1693 MallocCfg[off - opts] = val;
1700 MYMALLOC_WRITE2STDERR("Unrecognized part of PERL_MALLOC_OPT: \"");
1701 MYMALLOC_WRITE2STDERR(t);
1702 MYMALLOC_WRITE2STDERR("\"\n");
1705 MallocCfg[MallocCfg_cfg_env_read] = 1;
1709 if (bucket == sizeof(MEM_SIZE)*8*BUCKETS_PER_POW2) {
1711 croak("%s", "Out of memory during ridiculously large request");
1713 if (bucket > max_bucket)
1714 max_bucket = bucket;
1716 rnu = ( (bucket <= (LOG_OF_MIN_ARENA << BUCKET_POW2_SHIFT))
1718 : (bucket >> BUCKET_POW2_SHIFT) );
1719 /* This may be overwritten later: */
1720 nblks = 1 << (rnu - (bucket >> BUCKET_POW2_SHIFT)); /* how many blocks to get */
1721 needed = ((MEM_SIZE)1 << rnu) + POW2_OPTIMIZE_SURPLUS(bucket);
1722 if (nextf[rnu << BUCKET_POW2_SHIFT]) { /* 2048b bucket. */
1723 ovp = nextf[rnu << BUCKET_POW2_SHIFT] - 1 + CHUNK_SHIFT;
1724 nextf[rnu << BUCKET_POW2_SHIFT]
1725 = nextf[rnu << BUCKET_POW2_SHIFT]->ov_next;
1726 #ifdef DEBUGGING_MSTATS
1727 nmalloc[rnu << BUCKET_POW2_SHIFT]--;
1728 start_slack -= M_OVERHEAD;
1730 DEBUG_m(PerlIO_printf(Perl_debug_log,
1731 "stealing %ld bytes from %ld arena\n",
1732 (long) needed, (long) rnu << BUCKET_POW2_SHIFT));
1733 } else if (chunk_chain
1734 && (ovp = (union overhead*) get_from_chain(needed))) {
1735 DEBUG_m(PerlIO_printf(Perl_debug_log,
1736 "stealing %ld bytes from chain\n",
1738 } else if ( (ovp = (union overhead*)
1739 get_from_bigger_buckets((rnu << BUCKET_POW2_SHIFT) + 1,
1741 DEBUG_m(PerlIO_printf(Perl_debug_log,
1742 "stealing %ld bytes from bigger buckets\n",
1744 } else if (needed <= sbrked_remains) {
1745 ovp = (union overhead *)(last_sbrk_top - sbrked_remains);
1746 sbrked_remains -= needed;
1747 last_op = (char*)ovp;
1749 ovp = getpages(needed, &nblks, bucket);
1753 FILL_DEADBEEF((unsigned char*)ovp, needed);
1756 * Add new memory allocated to that on
1757 * free list for this hash bucket.
1759 siz = BUCKET_SIZE_NO_SURPLUS(bucket); /* No surplus if nblks > 1 */
1761 *(u_char*)ovp = bucket; /* Fill index. */
1762 if (bucket <= MAX_PACKED) {
1763 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1764 nblks = N_BLKS(bucket);
1765 # ifdef DEBUGGING_MSTATS
1766 start_slack += BLK_SHIFT(bucket);
1768 } else if (bucket < LOG_OF_MIN_ARENA * BUCKETS_PER_POW2) {
1769 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1770 siz -= sizeof(union overhead);
1771 } else ovp++; /* One chunk per block. */
1772 #endif /* PACK_MALLOC */
1773 nextf[bucket] = ovp;
1774 #ifdef DEBUGGING_MSTATS
1775 nmalloc[bucket] += nblks;
1776 if (bucket > MAX_PACKED) {
1777 start_slack += M_OVERHEAD * nblks;
1781 while (--nblks > 0) {
1782 ovp->ov_next = (union overhead *)((caddr_t)ovp + siz);
1783 ovp = (union overhead *)((caddr_t)ovp + siz);
1785 /* Not all sbrks return zeroed memory.*/
1786 ovp->ov_next = (union overhead *)NULL;
1788 if (bucket == 7*BUCKETS_PER_POW2) { /* Special case, explanation is above. */
1789 union overhead *n_op = nextf[7*BUCKETS_PER_POW2]->ov_next;
1790 nextf[7*BUCKETS_PER_POW2] =
1791 (union overhead *)((caddr_t)nextf[7*BUCKETS_PER_POW2]
1792 - sizeof(union overhead));
1793 nextf[7*BUCKETS_PER_POW2]->ov_next = n_op;
1795 #endif /* !PACK_MALLOC */
1801 Implements L<perlapi/C<Safefree>> which you should use instead.
1807 Perl_mfree(Malloc_t where)
1810 union overhead *ovp;
1811 char *cp = (char*)where;
1816 DEBUG_m(PerlIO_printf(Perl_debug_log,
1817 "0x%" UVxf ": (%05lu) free\n",
1818 PTR2UV(cp), (unsigned long)(PL_an++)));
1823 if (PTR2UV(cp) & (MEM_ALIGNBYTES - 1))
1824 croak("%s", "wrong alignment in free()");
1826 ovp = (union overhead *)((caddr_t)cp
1827 - sizeof (union overhead) * CHUNK_SHIFT);
1829 bucket = OV_INDEX(ovp);
1831 #ifdef IGNORE_SMALL_BAD_FREE
1832 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
1833 && (OV_MAGIC(ovp, bucket) != MAGIC))
1835 if (OV_MAGIC(ovp, bucket) != MAGIC)
1838 static int bad_free_warn = -1;
1839 if (bad_free_warn == -1) {
1841 char *pbf = PerlEnv_getenv("PERL_BADFREE");
1842 bad_free_warn = (pbf) ? strNE("0", pbf) : 1;
1849 if (!PERL_IS_ALIVE || !PL_curcop)
1850 Perl_ck_warner_d(aTHX_ packWARN(WARN_MALLOC), "%s free() ignored (RMAGIC, PERL_CORE)",
1851 ovp->ov_rmagic == RMAGIC - 1 ?
1852 "Duplicate" : "Bad");
1857 if (!PERL_IS_ALIVE || !PL_curcop)
1858 Perl_ck_warner_d(aTHX_ packWARN(WARN_MALLOC), "%s", "Bad free() ignored (PERL_CORE)");
1861 return; /* sanity */
1864 ASSERT(ovp->ov_rmagic == RMAGIC, "chunk's head overwrite");
1865 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
1867 MEM_SIZE nbytes = ovp->ov_size + 1;
1869 if ((i = nbytes & (RMAGIC_SZ-1))) {
1871 while (i--) { /* nbytes - RMAGIC_SZ is end of alloced area */
1872 ASSERT(((caddr_t)ovp + nbytes - RMAGIC_SZ)[i] == RMAGIC_C,
1873 "chunk's tail overwrite");
1876 /* Same at RMAGIC_SZ-aligned RMAGIC */
1877 nbytes = (nbytes + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ-1);
1878 ASSERT(((u_int *)((caddr_t)ovp + nbytes))[-1] == RMAGIC,
1879 "chunk's tail overwrite");
1880 FILLCHECK_DEADBEEF((unsigned char*)((caddr_t)ovp + nbytes),
1881 BUCKET_SIZE(OV_INDEX(ovp)) - nbytes);
1883 FILL_DEADBEEF((unsigned char*)(ovp+CHUNK_SHIFT),
1884 BUCKET_SIZE_REAL(OV_INDEX(ovp)) + RMAGIC_SZ);
1885 ovp->ov_rmagic = RMAGIC - 1;
1887 ASSERT(OV_INDEX(ovp) < NBUCKETS, "chunk's head overwrite");
1888 size = OV_INDEX(ovp);
1891 ovp->ov_next = nextf[size];
1899 Implements L<perlapi/C<Renew>> which you should use instead.
1904 /* There is no need to do any locking in realloc (with an exception of
1905 trying to grow in place if we are at the end of the chain).
1906 If somebody calls us from a different thread with the same address,
1907 we are sole anyway. */
1910 Perl_realloc(void *mp, size_t nbytes)
1913 union overhead *ovp;
1917 int incr; /* 1 if does not fit, -1 if "easily" fits in a
1918 smaller bucket, otherwise 0. */
1919 char *cp = (char*)mp;
1922 MEM_SIZE size = nbytes;
1924 if ((long)nbytes < 0)
1925 croak("%s", "panic: realloc");
1928 BARK_64K_LIMIT("Reallocation",nbytes,size);
1930 return Perl_malloc(nbytes);
1932 ovp = (union overhead *)((caddr_t)cp
1933 - sizeof (union overhead) * CHUNK_SHIFT);
1934 bucket = OV_INDEX(ovp);
1936 #ifdef IGNORE_SMALL_BAD_FREE
1937 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
1938 && (OV_MAGIC(ovp, bucket) != MAGIC))
1940 if (OV_MAGIC(ovp, bucket) != MAGIC)
1943 static int bad_free_warn = -1;
1944 if (bad_free_warn == -1) {
1946 char *pbf = PerlEnv_getenv("PERL_BADFREE");
1947 bad_free_warn = (pbf) ? strNE("0", pbf) : 1;
1954 if (!PERL_IS_ALIVE || !PL_curcop)
1955 Perl_ck_warner_d(aTHX_ packWARN(WARN_MALLOC), "%srealloc() %signored",
1956 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
1957 ovp->ov_rmagic == RMAGIC - 1
1958 ? "of freed memory " : "");
1963 if (!PERL_IS_ALIVE || !PL_curcop)
1964 Perl_ck_warner_d(aTHX_ packWARN(WARN_MALLOC), "%s",
1965 "Bad realloc() ignored");
1968 return NULL; /* sanity */
1971 onb = BUCKET_SIZE_REAL(bucket);
1973 * avoid the copy if same size block.
1974 * We are not aggressive with boundary cases. Note that it might
1975 * (for a small number of cases) give false negative if
1976 * both new size and old one are in the bucket for
1977 * FIRST_BIG_POW2, but the new one is near the lower end.
1979 * We do not try to go to 1.5 times smaller bucket so far.
1981 if (nbytes > onb) incr = 1;
1983 #ifdef DO_NOT_TRY_HARDER_WHEN_SHRINKING
1984 if ( /* This is a little bit pessimal if PACK_MALLOC: */
1985 nbytes > ( (onb >> 1) - M_OVERHEAD )
1986 # ifdef TWO_POT_OPTIMIZE
1987 || (bucket == FIRST_BIG_POW2 && nbytes >= LAST_SMALL_BOUND )
1990 #else /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
1991 prev_bucket = ( (bucket > MAX_PACKED + 1)
1992 ? bucket - BUCKETS_PER_POW2
1994 if (nbytes > BUCKET_SIZE_REAL(prev_bucket))
1995 #endif /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
1999 #ifdef STRESS_REALLOC
2006 * Record new allocated size of block and
2007 * bound space with magic numbers.
2009 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
2010 int i, nb = ovp->ov_size + 1;
2012 if ((i = nb & (RMAGIC_SZ-1))) {
2014 while (i--) { /* nb - RMAGIC_SZ is end of alloced area */
2015 ASSERT(((caddr_t)ovp + nb - RMAGIC_SZ)[i] == RMAGIC_C, "chunk's tail overwrite");
2018 /* Same at RMAGIC_SZ-aligned RMAGIC */
2019 nb = (nb + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ-1);
2020 ASSERT(((u_int *)((caddr_t)ovp + nb))[-1] == RMAGIC,
2021 "chunk's tail overwrite");
2022 FILLCHECK_DEADBEEF((unsigned char*)((caddr_t)ovp + nb),
2023 BUCKET_SIZE(OV_INDEX(ovp)) - nb);
2024 if (nbytes > ovp->ov_size + 1 - M_OVERHEAD)
2025 FILL_FEEDADAD((unsigned char*)cp + ovp->ov_size + 1 - M_OVERHEAD,
2026 nbytes - (ovp->ov_size + 1 - M_OVERHEAD));
2028 FILL_DEADBEEF((unsigned char*)cp + nbytes,
2029 nb - M_OVERHEAD + RMAGIC_SZ - nbytes);
2031 * Convert amount of memory requested into
2032 * closest block size stored in hash buckets
2033 * which satisfies request. Account for
2034 * space used per block for accounting.
2036 nbytes += M_OVERHEAD;
2037 ovp->ov_size = nbytes - 1;
2038 if ((i = nbytes & (RMAGIC_SZ-1))) {
2040 while (i--) /* nbytes - RMAGIC_SZ is end of alloced area */
2041 ((caddr_t)ovp + nbytes - RMAGIC_SZ)[i]
2044 /* Same at RMAGIC_SZ-aligned RMAGIC */
2045 nbytes = (nbytes + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ - 1);
2046 ((u_int *)((caddr_t)ovp + nbytes))[-1] = RMAGIC;
2050 DEBUG_m(PerlIO_printf(Perl_debug_log,
2051 "0x%" UVxf ": (%05lu) realloc %ld bytes inplace\n",
2052 PTR2UV(res),(unsigned long)(PL_an++),
2054 } else if (incr == 1 && (cp - M_OVERHEAD == last_op)
2055 && (onb > (1 << LOG_OF_MIN_ARENA))) {
2056 MEM_SIZE require, newarena = nbytes, pow;
2059 POW2_OPTIMIZE_ADJUST(newarena);
2060 newarena = newarena + M_OVERHEAD;
2061 /* newarena = (newarena + 3) &~ 3; */
2062 shiftr = (newarena - 1) >> LOG_OF_MIN_ARENA;
2063 pow = LOG_OF_MIN_ARENA + 1;
2064 /* apart from this loop, this is O(1) */
2065 while (shiftr >>= 1)
2067 newarena = (1 << pow) + POW2_OPTIMIZE_SURPLUS(pow * BUCKETS_PER_POW2);
2068 require = newarena - onb - M_OVERHEAD;
2071 if (cp - M_OVERHEAD == last_op /* We *still* are the last chunk */
2072 && getpages_adjacent(require)) {
2073 #ifdef DEBUGGING_MSTATS
2075 nmalloc[pow * BUCKETS_PER_POW2]++;
2077 if (pow * BUCKETS_PER_POW2 > (MEM_SIZE)max_bucket)
2078 max_bucket = pow * BUCKETS_PER_POW2;
2079 *(cp - M_OVERHEAD) = pow * BUCKETS_PER_POW2; /* Fill index. */
2088 DEBUG_m(PerlIO_printf(Perl_debug_log,
2089 "0x%" UVxf ": (%05lu) realloc %ld bytes the hard way\n",
2090 PTR2UV(cp),(unsigned long)(PL_an++),
2092 if ((res = (char*)Perl_malloc(nbytes)) == NULL)
2094 if (cp != res) /* common optimization */
2095 Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char);
2098 return ((Malloc_t)res);
2104 Implements L<perlapi/C<Newxz>> which you should use instead.
2110 Perl_calloc(size_t elements, size_t size)
2112 long sz = elements * size;
2113 Malloc_t p = Perl_malloc(sz);
2116 memset((void*)p, 0, sz);
2122 Perl_strdup(const char *s)
2124 MEM_SIZE l = strlen(s);
2125 char *s1 = (char *)Perl_malloc(l+1);
2127 return (char *)CopyD(s, s1, (MEM_SIZE)(l+1), char);
2131 Perl_putenv(char *a)
2133 /* Sometimes system's putenv conflicts with my_setenv() - this is system
2134 malloc vs Perl's free(). */
2141 while (*val && *val != '=')
2146 if (l < sizeof(buf))
2149 var = (char *)Perl_malloc(l + 1);
2150 Copy(a, var, l, char);
2152 my_setenv(var, val+1);
2159 Perl_malloced_size(void *p)
2161 union overhead * const ovp = (union overhead *)
2162 ((caddr_t)p - sizeof (union overhead) * CHUNK_SHIFT);
2163 const int bucket = OV_INDEX(ovp);
2165 PERL_ARGS_ASSERT_MALLOCED_SIZE;
2168 /* The caller wants to have a complete control over the chunk,
2169 disable the memory checking inside the chunk. */
2170 if (bucket <= MAX_SHORT_BUCKET) {
2171 const MEM_SIZE size = BUCKET_SIZE_REAL(bucket);
2172 ovp->ov_size = size + M_OVERHEAD - 1;
2173 *((u_int *)((caddr_t)ovp + size + M_OVERHEAD - RMAGIC_SZ)) = RMAGIC;
2176 return BUCKET_SIZE_REAL(bucket);
2181 Perl_malloc_good_size(size_t wanted)
2183 return BUCKET_SIZE_REAL(adjust_size_and_find_bucket(&wanted));
2186 # ifdef BUCKETS_ROOT2
2187 # define MIN_EVEN_REPORT 6
2189 # define MIN_EVEN_REPORT MIN_BUCKET
2193 Perl_get_mstats(pTHX_ perl_mstats_t *buf, int buflen, int level)
2195 #ifdef DEBUGGING_MSTATS
2198 struct chunk_chain_s* nextchain;
2200 PERL_ARGS_ASSERT_GET_MSTATS;
2202 buf->topbucket = buf->topbucket_ev = buf->topbucket_odd
2203 = buf->totfree = buf->total = buf->total_chain = 0;
2205 buf->minbucket = MIN_BUCKET;
2207 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
2208 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
2212 buf->ntotal[i] = nmalloc[i];
2214 buf->totfree += j * BUCKET_SIZE_REAL(i);
2215 buf->total += nmalloc[i] * BUCKET_SIZE_REAL(i);
2217 i % 2 ? (buf->topbucket_odd = i) : (buf->topbucket_ev = i);
2221 nextchain = chunk_chain;
2223 buf->total_chain += nextchain->size;
2224 nextchain = nextchain->next;
2226 buf->total_sbrk = goodsbrk + sbrk_slack;
2228 buf->sbrk_good = sbrk_goodness;
2229 buf->sbrk_slack = sbrk_slack;
2230 buf->start_slack = start_slack;
2231 buf->sbrked_remains = sbrked_remains;
2233 buf->nbuckets = NBUCKETS;
2235 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
2238 buf->bucket_mem_size[i] = BUCKET_SIZE_NO_SURPLUS(i);
2239 buf->bucket_available_size[i] = BUCKET_SIZE_REAL(i);
2242 #else /* defined DEBUGGING_MSTATS */
2243 PerlIO_printf(Perl_error_log, "perl not compiled with DEBUGGING_MSTATS\n");
2244 #endif /* defined DEBUGGING_MSTATS */
2245 return 0; /* XXX unused */
2249 =for apidoc dump_mstats
2251 When enabled by compiling with C<-DDEBUGGING_MSTATS>, print out statistics
2252 about malloc as two lines of numbers, one showing the length of the free list
2253 for each size category, the second showing the number of S<mallocs - frees> for
2256 C<s>, if not NULL, is used as a phrase to include in the output, such as
2257 S<"after compilation">.
2263 Perl_dump_mstats(pTHX_ const char *s)
2265 #ifdef DEBUGGING_MSTATS
2267 perl_mstats_t buffer;
2271 PERL_ARGS_ASSERT_DUMP_MSTATS;
2275 get_mstats(&buffer, NBUCKETS, 0);
2278 PerlIO_printf(Perl_error_log,
2279 "Memory allocation statistics %s (buckets %" IVdf
2280 "(%" IVdf ")..%" IVdf "(%" IVdf ")\n",
2282 (IV)BUCKET_SIZE_REAL(MIN_BUCKET),
2283 (IV)BUCKET_SIZE_NO_SURPLUS(MIN_BUCKET),
2284 (IV)BUCKET_SIZE_REAL(buffer.topbucket),
2285 (IV)BUCKET_SIZE_NO_SURPLUS(buffer.topbucket));
2286 PerlIO_printf(Perl_error_log, "%8" IVdf " free:", buffer.totfree);
2287 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
2288 PerlIO_printf(Perl_error_log,
2289 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2291 : ((i < 12*BUCKETS_PER_POW2) ? " %3" UVuf
2295 #ifdef BUCKETS_ROOT2
2296 PerlIO_printf(Perl_error_log, "\n\t ");
2297 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
2298 PerlIO_printf(Perl_error_log,
2299 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2301 : ((i < 12*BUCKETS_PER_POW2) ? " %3"UVuf : " %"UVuf)),
2305 PerlIO_printf(Perl_error_log, "\n%8" IVdf " used:",
2306 buffer.total - buffer.totfree);
2307 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
2308 PerlIO_printf(Perl_error_log,
2309 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2311 : ((i < 12*BUCKETS_PER_POW2) ? " %3" IVdf : " %" IVdf)),
2312 buffer.ntotal[i] - buffer.nfree[i]);
2314 #ifdef BUCKETS_ROOT2
2315 PerlIO_printf(Perl_error_log, "\n\t ");
2316 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
2317 PerlIO_printf(Perl_error_log,
2318 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2320 : ((i < 12*BUCKETS_PER_POW2) ? " %3"IVdf : " %"IVdf)),
2321 buffer.ntotal[i] - buffer.nfree[i]);
2324 PerlIO_printf(Perl_error_log, "\nTotal sbrk(): %" IVdf "/%" IVdf ":%"
2325 IVdf ". Odd ends: pad+heads+chain+tail: %" IVdf "+%"
2326 IVdf "+%" IVdf "+%" IVdf ".\n",
2327 buffer.total_sbrk, buffer.sbrks, buffer.sbrk_good,
2328 buffer.sbrk_slack, buffer.start_slack,
2329 buffer.total_chain, buffer.sbrked_remains);
2330 #else /* DEBUGGING_MSTATS */
2331 PerlIO_printf(Perl_error_log, "%s: perl not compiled with DEBUGGING_MSTATS\n",s);
2332 #endif /* DEBUGGING_MSTATS */
2335 #ifdef USE_PERL_SBRK
2337 # if defined(PURIFY)
2338 # define PERL_SBRK_VIA_MALLOC
2341 # ifdef PERL_SBRK_VIA_MALLOC
2343 /* it may seem schizophrenic to use perl's malloc and let it call system */
2344 /* malloc, the reason for that is only the 3.2 version of the OS that had */
2345 /* frequent core dumps within nxzonefreenolock. This sbrk routine put an */
2346 /* end to the cores */
2348 # ifndef SYSTEM_ALLOC
2349 # define SYSTEM_ALLOC(a) malloc(a)
2351 # ifndef SYSTEM_ALLOC_ALIGNMENT
2352 # define SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES
2355 # endif /* PERL_SBRK_VIA_MALLOC */
2357 static IV Perl_sbrk_oldchunk;
2358 static long Perl_sbrk_oldsize;
2360 # define PERLSBRK_32_K (1<<15)
2361 # define PERLSBRK_64_K (1<<16)
2369 if (!size) return 0;
2370 reqsize = size; /* just for the DEBUG_m statement */
2372 size = (size + 0x7ff) & ~0x7ff;
2374 if (size <= Perl_sbrk_oldsize) {
2375 got = Perl_sbrk_oldchunk;
2376 Perl_sbrk_oldchunk += size;
2377 Perl_sbrk_oldsize -= size;
2379 if (size >= PERLSBRK_32_K) {
2382 size = PERLSBRK_64_K;
2385 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2386 size += NEEDED_ALIGNMENT - SYSTEM_ALLOC_ALIGNMENT;
2388 got = (IV)SYSTEM_ALLOC(size);
2389 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2390 got = (got + NEEDED_ALIGNMENT - 1) & ~(NEEDED_ALIGNMENT - 1);
2393 /* Chunk is small, register the rest for future allocs. */
2394 Perl_sbrk_oldchunk = got + reqsize;
2395 Perl_sbrk_oldsize = size - reqsize;
2399 DEBUG_m(PerlIO_printf(Perl_debug_log,
2400 "sbrk malloc size %ld (reqsize %ld), left size %ld, give addr 0x%"
2402 size, reqsize, Perl_sbrk_oldsize, PTR2UV(got)));
2407 #endif /* ! defined USE_PERL_SBRK */
2410 * ex: set ts=8 sts=4 sw=4 et: