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(PERL_IMPLICIT_CONTEXT)
242 # define croak Perl_croak_nocontext
243 # define croak2 Perl_croak_nocontext
244 # define warn Perl_warn_nocontext
245 # define warn2 Perl_warn_nocontext
247 # define croak2 croak
251 # define PERL_MAYBE_ALIVE PL_thr_key
253 # define PERL_MAYBE_ALIVE 1
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; \
291 #ifdef PERL_IMPLICIT_CONTEXT
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 \
466 : ((1 << ((i) >> BUCKET_POW2_SHIFT)) \
468 + POW2_OPTIMIZE_SURPLUS(i)))
470 # define BUCKET_SIZE_NO_SURPLUS(i) (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 sacrifised 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 ((1<<LOG_OF_MIN_ARENA) - 1)
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 ? ((1<<LOG_OF_MIN_ARENA) - 1)/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 ? 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 ((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) 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);
822 # ifndef HAS_SBRK_PROTO /* <unistd.h> usually takes care of this */
823 extern Malloc_t sbrk(int);
827 #ifndef MIN_SBRK_FRAC1000 /* Backward compatibility */
828 # define MIN_SBRK_FRAC1000 (MIN_SBRK_FRAC * 10)
831 #ifndef START_EXTERN_C
833 # define START_EXTERN_C extern "C" {
835 # define START_EXTERN_C
841 # define END_EXTERN_C };
843 # define END_EXTERN_C
847 #include "malloc_ctl.h"
849 #ifndef NO_MALLOC_DYNAMIC_CFG
850 # define PERL_MALLOC_OPT_CHARS "FMfAPGdac"
852 # ifndef FILL_DEAD_DEFAULT
853 # define FILL_DEAD_DEFAULT 1
855 # ifndef FILL_ALIVE_DEFAULT
856 # define FILL_ALIVE_DEFAULT 1
858 # ifndef FILL_CHECK_DEFAULT
859 # define FILL_CHECK_DEFAULT 1
862 static IV MallocCfg[MallocCfg_last] = {
868 SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE, /* sbrk_goodness */
869 FILL_DEAD_DEFAULT, /* FILL_DEAD */
870 FILL_ALIVE_DEFAULT, /* FILL_ALIVE */
871 FILL_CHECK_DEFAULT, /* FILL_CHECK */
872 0, /* MallocCfg_skip_cfg_env */
873 0, /* MallocCfg_cfg_env_read */
874 0, /* MallocCfg_emergency_buffer_size */
875 0, /* MallocCfg_emergency_buffer_prepared_size */
876 0 /* MallocCfg_emergency_buffer_last_req */
878 IV *MallocCfg_ptr = MallocCfg;
880 static char* MallocCfgP[MallocCfg_last] = {
881 0, /* MallocCfgP_emergency_buffer */
882 0, /* MallocCfgP_emergency_buffer_prepared */
884 char **MallocCfgP_ptr = MallocCfgP;
888 # undef MIN_SBRK_FRAC1000
889 # undef SBRK_ALLOW_FAILURES
890 # undef SBRK_FAILURE_PRICE
892 # define MIN_SBRK MallocCfg[MallocCfg_MIN_SBRK]
893 # define FIRST_SBRK MallocCfg[MallocCfg_FIRST_SBRK]
894 # define MIN_SBRK_FRAC1000 MallocCfg[MallocCfg_MIN_SBRK_FRAC1000]
895 # define SBRK_ALLOW_FAILURES MallocCfg[MallocCfg_SBRK_ALLOW_FAILURES]
896 # define SBRK_FAILURE_PRICE MallocCfg[MallocCfg_SBRK_FAILURE_PRICE]
898 # define sbrk_goodness MallocCfg[MallocCfg_sbrk_goodness]
900 # define emergency_buffer_size MallocCfg[MallocCfg_emergency_buffer_size]
901 # define emergency_buffer_last_req MallocCfg[MallocCfg_emergency_buffer_last_req]
903 # define FILL_DEAD MallocCfg[MallocCfg_filldead]
904 # define FILL_ALIVE MallocCfg[MallocCfg_fillalive]
905 # define FILL_CHECK_CFG MallocCfg[MallocCfg_fillcheck]
906 # define FILL_CHECK (FILL_DEAD && FILL_CHECK_CFG)
908 # define emergency_buffer MallocCfgP[MallocCfgP_emergency_buffer]
909 # define emergency_buffer_prepared MallocCfgP[MallocCfgP_emergency_buffer_prepared]
911 #else /* defined(NO_MALLOC_DYNAMIC_CFG) */
914 # define FILL_ALIVE 1
915 # define FILL_CHECK 1
916 static int sbrk_goodness = SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE;
918 # define NO_PERL_MALLOC_ENV
922 #ifdef DEBUGGING_MSTATS
924 * nmalloc[i] is the difference between the number of mallocs and frees
925 * for a given block size.
927 static u_int nmalloc[NBUCKETS];
928 static u_int sbrk_slack;
929 static u_int start_slack;
930 #else /* !( defined DEBUGGING_MSTATS ) */
931 # define sbrk_slack 0
934 static u_int goodsbrk;
936 #ifdef PERL_EMERGENCY_SBRK
939 # define BIG_SIZE (1<<16) /* 64K */
942 # ifdef NO_MALLOC_DYNAMIC_CFG
943 static MEM_SIZE emergency_buffer_size;
944 /* 0 if the last request for more memory succeeded.
945 Otherwise the size of the failing request. */
946 static MEM_SIZE emergency_buffer_last_req;
947 static char *emergency_buffer;
948 static char *emergency_buffer_prepared;
951 # ifndef emergency_sbrk_croak
952 # define emergency_sbrk_croak croak2
956 perl_get_emergency_buffer(IV *size)
959 /* First offense, give a possibility to recover by dieing. */
960 /* No malloc involved here: */
963 GV **gvp = (GV**)hv_fetchs(PL_defstash, "^M", FALSE);
965 if (!gvp) gvp = (GV**)hv_fetchs(PL_defstash, "\015", FALSE);
966 if (!gvp || !(sv = GvSV(*gvp)) || !SvPOK(sv)
967 || (SvLEN(sv) < (1<<LOG_OF_MIN_ARENA) - M_OVERHEAD))
968 return NULL; /* Now die die die... */
969 /* Got it, now detach SvPV: */
971 /* Check alignment: */
972 if ((PTR2UV(pv) - sizeof(union overhead)) & (NEEDED_ALIGNMENT - 1)) {
973 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
974 return NULL; /* die die die */
981 *size = malloced_size(pv) + M_OVERHEAD;
982 return pv - sizeof(union overhead);
984 # define PERL_GET_EMERGENCY_BUFFER(p) perl_get_emergency_buffer(p)
986 # ifndef NO_MALLOC_DYNAMIC_CFG
988 get_emergency_buffer(IV *size)
990 char *pv = emergency_buffer_prepared;
992 *size = MallocCfg[MallocCfg_emergency_buffer_prepared_size];
993 emergency_buffer_prepared = 0;
994 MallocCfg[MallocCfg_emergency_buffer_prepared_size] = 0;
998 # define GET_EMERGENCY_BUFFER(p) get_emergency_buffer(p)
999 # else /* NO_MALLOC_DYNAMIC_CFG */
1000 # define GET_EMERGENCY_BUFFER(p) NULL
1004 emergency_sbrk(MEM_SIZE size)
1006 MEM_SIZE rsize = (((size - 1)>>LOG_OF_MIN_ARENA) + 1)<<LOG_OF_MIN_ARENA;
1008 if (size >= BIG_SIZE
1009 && (!emergency_buffer_last_req ||
1010 (size < (MEM_SIZE)emergency_buffer_last_req))) {
1011 /* Give the possibility to recover, but avoid an infinite cycle. */
1013 emergency_buffer_last_req = size;
1014 emergency_sbrk_croak("Out of memory during \"large\" request for %"UVuf" bytes, total sbrk() is %"UVuf" bytes", (UV)size, (UV)(goodsbrk + sbrk_slack));
1017 if ((MEM_SIZE)emergency_buffer_size >= rsize) {
1018 char *old = emergency_buffer;
1020 emergency_buffer_size -= rsize;
1021 emergency_buffer += rsize;
1024 /* First offense, give a possibility to recover by dieing. */
1025 /* No malloc involved here: */
1027 char *pv = GET_EMERGENCY_BUFFER(&Size);
1030 if (emergency_buffer_size) {
1031 add_to_chain(emergency_buffer, emergency_buffer_size, 0);
1032 emergency_buffer_size = 0;
1033 emergency_buffer = NULL;
1038 pv = PERL_GET_EMERGENCY_BUFFER(&Size);
1042 return (char *)-1; /* Now die die die... */
1045 /* Check alignment: */
1046 if (PTR2UV(pv) & (NEEDED_ALIGNMENT - 1)) {
1049 PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n");
1050 return (char *)-1; /* die die die */
1053 emergency_buffer = pv;
1054 emergency_buffer_size = Size;
1058 emergency_sbrk_croak("Out of memory during request for %"UVuf" bytes, total sbrk() is %"UVuf" bytes", (UV)size, (UV)(goodsbrk + sbrk_slack));
1059 assert(0); /* NOTREACHED */
1063 #else /* !defined(PERL_EMERGENCY_SBRK) */
1064 # define emergency_sbrk(size) -1
1065 #endif /* defined PERL_EMERGENCY_SBRK */
1067 /* Don't use PerlIO buffered writes as they allocate memory. */
1068 #define MYMALLOC_WRITE2STDERR(s) PERL_UNUSED_RESULT(PerlLIO_write(PerlIO_fileno(PerlIO_stderr()),s,strlen(s)))
1072 #define ASSERT(p,diag) if (!(p)) botch(diag,STRINGIFY(p),__FILE__,__LINE__);
1075 botch(const char *diag, const char *s, const char *file, int line)
1079 if (!(PERL_MAYBE_ALIVE && PERL_GET_THX))
1082 if (PerlIO_printf(PerlIO_stderr(),
1083 "assertion botched (%s?): %s %s:%d\n",
1084 diag, s, file, line) != 0) {
1085 do_write: /* Can be initializing interpreter */
1086 MYMALLOC_WRITE2STDERR("assertion botched (");
1087 MYMALLOC_WRITE2STDERR(diag);
1088 MYMALLOC_WRITE2STDERR("?): ");
1089 MYMALLOC_WRITE2STDERR(s);
1090 MYMALLOC_WRITE2STDERR(" (");
1091 MYMALLOC_WRITE2STDERR(file);
1092 MYMALLOC_WRITE2STDERR(":");
1095 char *s = linebuf + sizeof(linebuf) - 1;
1099 *--s = '0' + (n % 10);
1101 MYMALLOC_WRITE2STDERR(s);
1103 MYMALLOC_WRITE2STDERR(")\n");
1109 #define ASSERT(p, diag)
1113 /* Fill should be long enough to cover long */
1115 fill_pat_4bytes(unsigned char *s, size_t nbytes, const unsigned char *fill)
1117 unsigned char *e = s + nbytes;
1119 const long lfill = *(long*)fill;
1121 if (PTR2UV(s) & (sizeof(long)-1)) { /* Align the pattern */
1122 int shift = sizeof(long) - (PTR2UV(s) & (sizeof(long)-1));
1123 unsigned const char *f = fill + sizeof(long) - shift;
1124 unsigned char *e1 = s + shift;
1130 while ((unsigned char*)(lp + 1) <= e)
1132 s = (unsigned char*)lp;
1136 /* Just malloc()ed */
1137 static const unsigned char fill_feedadad[] =
1138 {0xFE, 0xED, 0xAD, 0xAD, 0xFE, 0xED, 0xAD, 0xAD,
1139 0xFE, 0xED, 0xAD, 0xAD, 0xFE, 0xED, 0xAD, 0xAD};
1141 static const unsigned char fill_deadbeef[] =
1142 {0xDE, 0xAD, 0xBE, 0xEF, 0xDE, 0xAD, 0xBE, 0xEF,
1143 0xDE, 0xAD, 0xBE, 0xEF, 0xDE, 0xAD, 0xBE, 0xEF};
1144 # define FILL_DEADBEEF(s, n) \
1145 (void)(FILL_DEAD? (fill_pat_4bytes((s), (n), fill_deadbeef), 0) : 0)
1146 # define FILL_FEEDADAD(s, n) \
1147 (void)(FILL_ALIVE? (fill_pat_4bytes((s), (n), fill_feedadad), 0) : 0)
1149 # define FILL_DEADBEEF(s, n) ((void)0)
1150 # define FILL_FEEDADAD(s, n) ((void)0)
1151 # undef MALLOC_FILL_CHECK
1154 #ifdef MALLOC_FILL_CHECK
1156 cmp_pat_4bytes(unsigned char *s, size_t nbytes, const unsigned char *fill)
1158 unsigned char *e = s + nbytes;
1160 const long lfill = *(long*)fill;
1162 if (PTR2UV(s) & (sizeof(long)-1)) { /* Align the pattern */
1163 int shift = sizeof(long) - (PTR2UV(s) & (sizeof(long)-1));
1164 unsigned const char *f = fill + sizeof(long) - shift;
1165 unsigned char *e1 = s + shift;
1172 while ((unsigned char*)(lp + 1) <= e)
1175 s = (unsigned char*)lp;
1177 if (*s++ != *fill++)
1181 # define FILLCHECK_DEADBEEF(s, n) \
1182 ASSERT(!FILL_CHECK || !cmp_pat_4bytes(s, n, fill_deadbeef), \
1183 "free()ed/realloc()ed-away memory was overwritten")
1185 # define FILLCHECK_DEADBEEF(s, n) ((void)0)
1189 S_adjust_size_and_find_bucket(size_t *nbytes_p)
1195 PERL_ARGS_ASSERT_ADJUST_SIZE_AND_FIND_BUCKET;
1200 * Convert amount of memory requested into
1201 * closest block size stored in hash buckets
1202 * which satisfies request. Account for
1203 * space used per block for accounting.
1206 # ifdef SMALL_BUCKET_VIA_TABLE
1208 bucket = MIN_BUCKET;
1209 else if (nbytes <= SIZE_TABLE_MAX) {
1210 bucket = bucket_of[(nbytes - 1) >> BUCKET_TABLE_SHIFT];
1215 if (nbytes <= MAX_POW2_ALGO) goto do_shifts;
1220 POW2_OPTIMIZE_ADJUST(nbytes);
1221 nbytes += M_OVERHEAD;
1222 nbytes = (nbytes + 3) &~ 3;
1223 #if defined(PACK_MALLOC) && !defined(SMALL_BUCKET_VIA_TABLE)
1226 shiftr = (nbytes - 1) >> START_SHIFT;
1227 bucket = START_SHIFTS_BUCKET;
1228 /* apart from this loop, this is O(1) */
1229 while (shiftr >>= 1)
1230 bucket += BUCKETS_PER_POW2;
1237 Perl_malloc(size_t nbytes)
1243 #if defined(DEBUGGING) || defined(RCHECK)
1244 MEM_SIZE size = nbytes;
1247 BARK_64K_LIMIT("Allocation",nbytes,nbytes);
1249 if ((long)nbytes < 0)
1250 croak("%s", "panic: malloc");
1253 bucket = adjust_size_and_find_bucket(&nbytes);
1256 * If nothing in hash bucket right now,
1257 * request more memory from the system.
1259 if (nextf[bucket] == NULL)
1261 if ((p = nextf[bucket]) == NULL) {
1266 #if defined(PLAIN_MALLOC) && defined(NO_FANCY_MALLOC)
1267 MYMALLOC_WRITE2STDERR("Out of memory!\n");
1270 char *eb = buff + sizeof(buff) - 1;
1274 MYMALLOC_WRITE2STDERR("Out of memory during request for ");
1275 #if defined(DEBUGGING) || defined(RCHECK)
1280 *--s = '0' + (n % 10);
1282 MYMALLOC_WRITE2STDERR(s);
1283 MYMALLOC_WRITE2STDERR(" bytes, total sbrk() is ");
1285 n = goodsbrk + sbrk_slack;
1287 *--s = '0' + (n % 10);
1289 MYMALLOC_WRITE2STDERR(s);
1290 MYMALLOC_WRITE2STDERR(" bytes!\n");
1291 #endif /* defined(PLAIN_MALLOC) && defined(NO_FANCY_MALLOC) */
1298 /* remove from linked list */
1300 if ( (PTR2UV(p) & (MEM_ALIGNBYTES - 1))
1301 /* Can't get this low */
1302 || (p && PTR2UV(p) < (1<<LOG_OF_MIN_ARENA)) ) {
1304 PerlIO_printf(PerlIO_stderr(),
1305 "Unaligned pointer in the free chain 0x%"UVxf"\n",
1308 if ( (PTR2UV(p->ov_next) & (MEM_ALIGNBYTES - 1))
1309 || (p->ov_next && PTR2UV(p->ov_next) < (1<<LOG_OF_MIN_ARENA)) ) {
1311 PerlIO_printf(PerlIO_stderr(),
1312 "Unaligned \"next\" pointer in the free "
1313 "chain 0x%"UVxf" at 0x%"UVxf"\n",
1314 PTR2UV(p->ov_next), PTR2UV(p));
1317 nextf[bucket] = p->ov_next;
1321 DEBUG_m(PerlIO_printf(Perl_debug_log,
1322 "0x%"UVxf": (%05lu) malloc %ld bytes\n",
1323 PTR2UV((Malloc_t)(p + CHUNK_SHIFT)), (unsigned long)(PL_an++),
1326 FILLCHECK_DEADBEEF((unsigned char*)(p + CHUNK_SHIFT),
1327 BUCKET_SIZE_REAL(bucket) + RMAGIC_SZ);
1329 #ifdef IGNORE_SMALL_BAD_FREE
1330 if (bucket >= FIRST_BUCKET_WITH_CHECK)
1332 OV_MAGIC(p, bucket) = MAGIC;
1334 OV_INDEX(p) = bucket;
1338 * Record allocated size of block and
1339 * bound space with magic numbers.
1341 p->ov_rmagic = RMAGIC;
1342 if (bucket <= MAX_SHORT_BUCKET) {
1345 nbytes = size + M_OVERHEAD;
1346 p->ov_size = nbytes - 1;
1347 if ((i = nbytes & (RMAGIC_SZ-1))) {
1349 while (i--) /* nbytes - RMAGIC_SZ is end of alloced area */
1350 ((caddr_t)p + nbytes - RMAGIC_SZ)[i] = RMAGIC_C;
1352 /* Same at RMAGIC_SZ-aligned RMAGIC */
1353 nbytes = (nbytes + RMAGIC_SZ - 1) & ~(RMAGIC_SZ - 1);
1354 ((u_int *)((caddr_t)p + nbytes))[-1] = RMAGIC;
1356 FILL_FEEDADAD((unsigned char *)(p + CHUNK_SHIFT), size);
1358 return ((Malloc_t)(p + CHUNK_SHIFT));
1361 static char *last_sbrk_top;
1362 static char *last_op; /* This arena can be easily extended. */
1363 static MEM_SIZE sbrked_remains;
1365 #ifdef DEBUGGING_MSTATS
1369 struct chunk_chain_s {
1370 struct chunk_chain_s *next;
1373 static struct chunk_chain_s *chunk_chain;
1374 static int n_chunks;
1375 static char max_bucket;
1377 /* Cutoff a piece of one of the chunks in the chain. Prefer smaller chunk. */
1379 get_from_chain(MEM_SIZE size)
1381 struct chunk_chain_s *elt = chunk_chain, **oldp = &chunk_chain;
1382 struct chunk_chain_s **oldgoodp = NULL;
1383 long min_remain = LONG_MAX;
1386 if (elt->size >= size) {
1387 long remains = elt->size - size;
1388 if (remains >= 0 && remains < min_remain) {
1390 min_remain = remains;
1396 oldp = &( elt->next );
1399 if (!oldgoodp) return NULL;
1401 void *ret = *oldgoodp;
1402 struct chunk_chain_s *next = (*oldgoodp)->next;
1404 *oldgoodp = (struct chunk_chain_s *)((char*)ret + size);
1405 (*oldgoodp)->size = min_remain;
1406 (*oldgoodp)->next = next;
1409 void *ret = *oldgoodp;
1410 *oldgoodp = (*oldgoodp)->next;
1417 add_to_chain(void *p, MEM_SIZE size, MEM_SIZE chip)
1419 struct chunk_chain_s *next = chunk_chain;
1420 char *cp = (char*)p;
1423 chunk_chain = (struct chunk_chain_s *)cp;
1424 chunk_chain->size = size - chip;
1425 chunk_chain->next = next;
1430 get_from_bigger_buckets(int bucket, MEM_SIZE size)
1433 static int bucketprice[NBUCKETS];
1434 while (bucket <= max_bucket) {
1435 /* We postpone stealing from bigger buckets until we want it
1437 if (nextf[bucket] && bucketprice[bucket]++ >= price) {
1439 void *ret = (void*)(nextf[bucket] - 1 + CHUNK_SHIFT);
1440 bucketprice[bucket] = 0;
1441 if (((char*)nextf[bucket]) - M_OVERHEAD == last_op) {
1442 last_op = NULL; /* Disable optimization */
1444 nextf[bucket] = nextf[bucket]->ov_next;
1445 #ifdef DEBUGGING_MSTATS
1447 start_slack -= M_OVERHEAD;
1449 add_to_chain(ret, (BUCKET_SIZE_NO_SURPLUS(bucket) +
1450 POW2_OPTIMIZE_SURPLUS(bucket)),
1459 static union overhead *
1460 getpages(MEM_SIZE needed, int *nblksp, int bucket)
1463 /* Need to do (possibly expensive) system call. Try to
1464 optimize it for rare calling. */
1465 MEM_SIZE require = needed - sbrked_remains;
1467 union overhead *ovp;
1470 if (sbrk_goodness > 0) {
1471 if (!last_sbrk_top && require < (MEM_SIZE)FIRST_SBRK)
1472 require = FIRST_SBRK;
1473 else if (require < (MEM_SIZE)MIN_SBRK) require = MIN_SBRK;
1475 if (require < (Size_t)(goodsbrk * MIN_SBRK_FRAC1000 / 1000))
1476 require = goodsbrk * MIN_SBRK_FRAC1000 / 1000;
1477 require = ((require - 1 + MIN_SBRK) / MIN_SBRK) * MIN_SBRK;
1484 DEBUG_m(PerlIO_printf(Perl_debug_log,
1485 "sbrk(%ld) for %ld-byte-long arena\n",
1486 (long)require, (long) needed));
1487 cp = (char *)sbrk(require);
1488 #ifdef DEBUGGING_MSTATS
1491 if (cp == last_sbrk_top) {
1492 /* Common case, anything is fine. */
1494 ovp = (union overhead *) (cp - sbrked_remains);
1495 last_op = cp - sbrked_remains;
1496 sbrked_remains = require - (needed - sbrked_remains);
1497 } else if (cp == (char *)-1) { /* no more room! */
1498 ovp = (union overhead *)emergency_sbrk(needed);
1499 if (ovp == (union overhead *)-1)
1501 if (((char*)ovp) > last_op) { /* Cannot happen with current emergency_sbrk() */
1505 } else { /* Non-continuous or first sbrk(). */
1506 long add = sbrked_remains;
1509 if (sbrked_remains) { /* Put rest into chain, we
1510 cannot use it right now. */
1511 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1515 /* Second, check alignment. */
1518 /* WANTED_ALIGNMENT may be more than NEEDED_ALIGNMENT, but this may
1519 improve performance of memory access. */
1520 if (PTR2UV(cp) & (WANTED_ALIGNMENT - 1)) { /* Not aligned. */
1521 slack = WANTED_ALIGNMENT - (PTR2UV(cp) & (WANTED_ALIGNMENT - 1));
1526 DEBUG_m(PerlIO_printf(Perl_debug_log,
1527 "sbrk(%ld) to fix non-continuous/off-page sbrk:\n\t%ld for alignement,\t%ld were assumed to come from the tail of the previous sbrk\n",
1528 (long)add, (long) slack,
1529 (long) sbrked_remains));
1530 newcp = (char *)sbrk(add);
1531 #if defined(DEBUGGING_MSTATS)
1535 if (newcp != cp + require) {
1536 /* Too bad: even rounding sbrk() is not continuous.*/
1537 DEBUG_m(PerlIO_printf(Perl_debug_log,
1538 "failed to fix bad sbrk()\n"));
1542 fatalcroak("panic: Off-page sbrk\n");
1545 if (sbrked_remains) {
1547 #if defined(DEBUGGING_MSTATS)
1548 sbrk_slack += require;
1551 DEBUG_m(PerlIO_printf(Perl_debug_log,
1552 "straight sbrk(%ld)\n",
1554 cp = (char *)sbrk(require);
1555 #ifdef DEBUGGING_MSTATS
1558 if (cp == (char *)-1)
1561 sbrk_goodness = -1; /* Disable optimization!
1562 Continue with not-aligned... */
1565 require += sbrked_remains;
1569 if (last_sbrk_top) {
1570 sbrk_goodness -= SBRK_FAILURE_PRICE;
1573 ovp = (union overhead *) cp;
1575 * Round up to minimum allocation size boundary
1576 * and deduct from block count to reflect.
1579 # if NEEDED_ALIGNMENT > MEM_ALIGNBYTES
1580 if (PTR2UV(ovp) & (NEEDED_ALIGNMENT - 1))
1581 fatalcroak("Misalignment of sbrk()\n");
1584 if (PTR2UV(ovp) & (MEM_ALIGNBYTES - 1)) {
1585 DEBUG_m(PerlIO_printf(Perl_debug_log,
1586 "fixing sbrk(): %d bytes off machine alignment\n",
1587 (int)(PTR2UV(ovp) & (MEM_ALIGNBYTES - 1))));
1588 ovp = INT2PTR(union overhead *,(PTR2UV(ovp) + MEM_ALIGNBYTES) &
1589 (MEM_ALIGNBYTES - 1));
1591 # if defined(DEBUGGING_MSTATS)
1592 /* This is only approx. if TWO_POT_OPTIMIZE: */
1593 sbrk_slack += (1 << (bucket >> BUCKET_POW2_SHIFT));
1596 ; /* Finish "else" */
1597 sbrked_remains = require - needed;
1600 #if !defined(PLAIN_MALLOC) && !defined(NO_FANCY_MALLOC)
1601 emergency_buffer_last_req = 0;
1603 last_sbrk_top = cp + require;
1604 #ifdef DEBUGGING_MSTATS
1605 goodsbrk += require;
1611 getpages_adjacent(MEM_SIZE require)
1613 if (require <= sbrked_remains) {
1614 sbrked_remains -= require;
1618 require -= sbrked_remains;
1619 /* We do not try to optimize sbrks here, we go for place. */
1620 cp = (char*) sbrk(require);
1621 #ifdef DEBUGGING_MSTATS
1623 goodsbrk += require;
1625 if (cp == last_sbrk_top) {
1627 last_sbrk_top = cp + require;
1629 if (cp == (char*)-1) { /* Out of memory */
1630 #ifdef DEBUGGING_MSTATS
1631 goodsbrk -= require;
1635 /* Report the failure: */
1637 add_to_chain((void*)(last_sbrk_top - sbrked_remains),
1639 add_to_chain((void*)cp, require, 0);
1640 sbrk_goodness -= SBRK_FAILURE_PRICE;
1652 * Allocate more memory to the indicated bucket.
1655 morecore(int bucket)
1658 union overhead *ovp;
1659 int rnu; /* 2^rnu bytes will be requested */
1660 int nblks; /* become nblks blocks of the desired size */
1661 MEM_SIZE siz, needed;
1662 static int were_called = 0;
1666 #ifndef NO_PERL_MALLOC_ENV
1668 /* It's the our first time. Initialize ourselves */
1669 were_called = 1; /* Avoid a loop */
1670 if (!MallocCfg[MallocCfg_skip_cfg_env]) {
1671 char *s = getenv("PERL_MALLOC_OPT"), *t = s, *off;
1672 const char *opts = PERL_MALLOC_OPT_CHARS;
1675 while ( t && t[0] && t[1] == '='
1676 && ((off = strchr(opts, *t))) ) {
1680 while (*t <= '9' && *t >= '0')
1681 val = 10*val + *t++ - '0';
1682 if (!*t || *t == ';') {
1683 if (MallocCfg[off - opts] != val)
1685 MallocCfg[off - opts] = val;
1692 MYMALLOC_WRITE2STDERR("Unrecognized part of PERL_MALLOC_OPT: \"");
1693 MYMALLOC_WRITE2STDERR(t);
1694 MYMALLOC_WRITE2STDERR("\"\n");
1697 MallocCfg[MallocCfg_cfg_env_read] = 1;
1701 if (bucket == sizeof(MEM_SIZE)*8*BUCKETS_PER_POW2) {
1703 croak("%s", "Out of memory during ridiculously large request");
1705 if (bucket > max_bucket)
1706 max_bucket = bucket;
1708 rnu = ( (bucket <= (LOG_OF_MIN_ARENA << BUCKET_POW2_SHIFT))
1710 : (bucket >> BUCKET_POW2_SHIFT) );
1711 /* This may be overwritten later: */
1712 nblks = 1 << (rnu - (bucket >> BUCKET_POW2_SHIFT)); /* how many blocks to get */
1713 needed = ((MEM_SIZE)1 << rnu) + POW2_OPTIMIZE_SURPLUS(bucket);
1714 if (nextf[rnu << BUCKET_POW2_SHIFT]) { /* 2048b bucket. */
1715 ovp = nextf[rnu << BUCKET_POW2_SHIFT] - 1 + CHUNK_SHIFT;
1716 nextf[rnu << BUCKET_POW2_SHIFT]
1717 = nextf[rnu << BUCKET_POW2_SHIFT]->ov_next;
1718 #ifdef DEBUGGING_MSTATS
1719 nmalloc[rnu << BUCKET_POW2_SHIFT]--;
1720 start_slack -= M_OVERHEAD;
1722 DEBUG_m(PerlIO_printf(Perl_debug_log,
1723 "stealing %ld bytes from %ld arena\n",
1724 (long) needed, (long) rnu << BUCKET_POW2_SHIFT));
1725 } else if (chunk_chain
1726 && (ovp = (union overhead*) get_from_chain(needed))) {
1727 DEBUG_m(PerlIO_printf(Perl_debug_log,
1728 "stealing %ld bytes from chain\n",
1730 } else if ( (ovp = (union overhead*)
1731 get_from_bigger_buckets((rnu << BUCKET_POW2_SHIFT) + 1,
1733 DEBUG_m(PerlIO_printf(Perl_debug_log,
1734 "stealing %ld bytes from bigger buckets\n",
1736 } else if (needed <= sbrked_remains) {
1737 ovp = (union overhead *)(last_sbrk_top - sbrked_remains);
1738 sbrked_remains -= needed;
1739 last_op = (char*)ovp;
1741 ovp = getpages(needed, &nblks, bucket);
1745 FILL_DEADBEEF((unsigned char*)ovp, needed);
1748 * Add new memory allocated to that on
1749 * free list for this hash bucket.
1751 siz = BUCKET_SIZE_NO_SURPLUS(bucket); /* No surplus if nblks > 1 */
1753 *(u_char*)ovp = bucket; /* Fill index. */
1754 if (bucket <= MAX_PACKED) {
1755 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1756 nblks = N_BLKS(bucket);
1757 # ifdef DEBUGGING_MSTATS
1758 start_slack += BLK_SHIFT(bucket);
1760 } else if (bucket < LOG_OF_MIN_ARENA * BUCKETS_PER_POW2) {
1761 ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket));
1762 siz -= sizeof(union overhead);
1763 } else ovp++; /* One chunk per block. */
1764 #endif /* PACK_MALLOC */
1765 nextf[bucket] = ovp;
1766 #ifdef DEBUGGING_MSTATS
1767 nmalloc[bucket] += nblks;
1768 if (bucket > MAX_PACKED) {
1769 start_slack += M_OVERHEAD * nblks;
1773 while (--nblks > 0) {
1774 ovp->ov_next = (union overhead *)((caddr_t)ovp + siz);
1775 ovp = (union overhead *)((caddr_t)ovp + siz);
1777 /* Not all sbrks return zeroed memory.*/
1778 ovp->ov_next = (union overhead *)NULL;
1780 if (bucket == 7*BUCKETS_PER_POW2) { /* Special case, explanation is above. */
1781 union overhead *n_op = nextf[7*BUCKETS_PER_POW2]->ov_next;
1782 nextf[7*BUCKETS_PER_POW2] =
1783 (union overhead *)((caddr_t)nextf[7*BUCKETS_PER_POW2]
1784 - sizeof(union overhead));
1785 nextf[7*BUCKETS_PER_POW2]->ov_next = n_op;
1787 #endif /* !PACK_MALLOC */
1791 Perl_mfree(Malloc_t where)
1795 union overhead *ovp;
1796 char *cp = (char*)where;
1801 DEBUG_m(PerlIO_printf(Perl_debug_log,
1802 "0x%"UVxf": (%05lu) free\n",
1803 PTR2UV(cp), (unsigned long)(PL_an++)));
1808 if (PTR2UV(cp) & (MEM_ALIGNBYTES - 1))
1809 croak("%s", "wrong alignment in free()");
1811 ovp = (union overhead *)((caddr_t)cp
1812 - sizeof (union overhead) * CHUNK_SHIFT);
1814 bucket = OV_INDEX(ovp);
1816 #ifdef IGNORE_SMALL_BAD_FREE
1817 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
1818 && (OV_MAGIC(ovp, bucket) != MAGIC))
1820 if (OV_MAGIC(ovp, bucket) != MAGIC)
1823 static int bad_free_warn = -1;
1824 if (bad_free_warn == -1) {
1826 char *pbf = PerlEnv_getenv("PERL_BADFREE");
1827 bad_free_warn = (pbf) ? grok_atou(pbf, NULL) : 1;
1834 if (!PERL_IS_ALIVE || !PL_curcop)
1835 Perl_ck_warner_d(aTHX_ packWARN(WARN_MALLOC), "%s free() ignored (RMAGIC, PERL_CORE)",
1836 ovp->ov_rmagic == RMAGIC - 1 ?
1837 "Duplicate" : "Bad");
1842 if (!PERL_IS_ALIVE || !PL_curcop)
1843 Perl_ck_warner_d(aTHX_ packWARN(WARN_MALLOC), "%s", "Bad free() ignored (PERL_CORE)");
1846 return; /* sanity */
1849 ASSERT(ovp->ov_rmagic == RMAGIC, "chunk's head overwrite");
1850 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
1852 MEM_SIZE nbytes = ovp->ov_size + 1;
1854 if ((i = nbytes & (RMAGIC_SZ-1))) {
1856 while (i--) { /* nbytes - RMAGIC_SZ is end of alloced area */
1857 ASSERT(((caddr_t)ovp + nbytes - RMAGIC_SZ)[i] == RMAGIC_C,
1858 "chunk's tail overwrite");
1861 /* Same at RMAGIC_SZ-aligned RMAGIC */
1862 nbytes = (nbytes + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ-1);
1863 ASSERT(((u_int *)((caddr_t)ovp + nbytes))[-1] == RMAGIC,
1864 "chunk's tail overwrite");
1865 FILLCHECK_DEADBEEF((unsigned char*)((caddr_t)ovp + nbytes),
1866 BUCKET_SIZE(OV_INDEX(ovp)) - nbytes);
1868 FILL_DEADBEEF((unsigned char*)(ovp+CHUNK_SHIFT),
1869 BUCKET_SIZE_REAL(OV_INDEX(ovp)) + RMAGIC_SZ);
1870 ovp->ov_rmagic = RMAGIC - 1;
1872 ASSERT(OV_INDEX(ovp) < NBUCKETS, "chunk's head overwrite");
1873 size = OV_INDEX(ovp);
1876 ovp->ov_next = nextf[size];
1881 /* There is no need to do any locking in realloc (with an exception of
1882 trying to grow in place if we are at the end of the chain).
1883 If somebody calls us from a different thread with the same address,
1884 we are sole anyway. */
1887 Perl_realloc(void *mp, size_t nbytes)
1891 union overhead *ovp;
1895 int incr; /* 1 if does not fit, -1 if "easily" fits in a
1896 smaller bucket, otherwise 0. */
1897 char *cp = (char*)mp;
1900 MEM_SIZE size = nbytes;
1902 if ((long)nbytes < 0)
1903 croak("%s", "panic: realloc");
1906 BARK_64K_LIMIT("Reallocation",nbytes,size);
1908 return Perl_malloc(nbytes);
1910 ovp = (union overhead *)((caddr_t)cp
1911 - sizeof (union overhead) * CHUNK_SHIFT);
1912 bucket = OV_INDEX(ovp);
1914 #ifdef IGNORE_SMALL_BAD_FREE
1915 if ((bucket >= FIRST_BUCKET_WITH_CHECK)
1916 && (OV_MAGIC(ovp, bucket) != MAGIC))
1918 if (OV_MAGIC(ovp, bucket) != MAGIC)
1921 static int bad_free_warn = -1;
1922 if (bad_free_warn == -1) {
1924 char *pbf = PerlEnv_getenv("PERL_BADFREE");
1925 bad_free_warn = (pbf) ? grok_atou(pbf, NULL) : 1;
1932 if (!PERL_IS_ALIVE || !PL_curcop)
1933 Perl_ck_warner_d(aTHX_ packWARN(WARN_MALLOC), "%srealloc() %signored",
1934 (ovp->ov_rmagic == RMAGIC - 1 ? "" : "Bad "),
1935 ovp->ov_rmagic == RMAGIC - 1
1936 ? "of freed memory " : "");
1941 if (!PERL_IS_ALIVE || !PL_curcop)
1942 Perl_ck_warner_d(aTHX_ packWARN(WARN_MALLOC), "%s",
1943 "Bad realloc() ignored");
1946 return NULL; /* sanity */
1949 onb = BUCKET_SIZE_REAL(bucket);
1951 * avoid the copy if same size block.
1952 * We are not aggressive with boundary cases. Note that it might
1953 * (for a small number of cases) give false negative if
1954 * both new size and old one are in the bucket for
1955 * FIRST_BIG_POW2, but the new one is near the lower end.
1957 * We do not try to go to 1.5 times smaller bucket so far.
1959 if (nbytes > onb) incr = 1;
1961 #ifdef DO_NOT_TRY_HARDER_WHEN_SHRINKING
1962 if ( /* This is a little bit pessimal if PACK_MALLOC: */
1963 nbytes > ( (onb >> 1) - M_OVERHEAD )
1964 # ifdef TWO_POT_OPTIMIZE
1965 || (bucket == FIRST_BIG_POW2 && nbytes >= LAST_SMALL_BOUND )
1968 #else /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
1969 prev_bucket = ( (bucket > MAX_PACKED + 1)
1970 ? bucket - BUCKETS_PER_POW2
1972 if (nbytes > BUCKET_SIZE_REAL(prev_bucket))
1973 #endif /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */
1977 #ifdef STRESS_REALLOC
1984 * Record new allocated size of block and
1985 * bound space with magic numbers.
1987 if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) {
1988 int i, nb = ovp->ov_size + 1;
1990 if ((i = nb & (RMAGIC_SZ-1))) {
1992 while (i--) { /* nb - RMAGIC_SZ is end of alloced area */
1993 ASSERT(((caddr_t)ovp + nb - RMAGIC_SZ)[i] == RMAGIC_C, "chunk's tail overwrite");
1996 /* Same at RMAGIC_SZ-aligned RMAGIC */
1997 nb = (nb + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ-1);
1998 ASSERT(((u_int *)((caddr_t)ovp + nb))[-1] == RMAGIC,
1999 "chunk's tail overwrite");
2000 FILLCHECK_DEADBEEF((unsigned char*)((caddr_t)ovp + nb),
2001 BUCKET_SIZE(OV_INDEX(ovp)) - nb);
2002 if (nbytes > ovp->ov_size + 1 - M_OVERHEAD)
2003 FILL_FEEDADAD((unsigned char*)cp + ovp->ov_size + 1 - M_OVERHEAD,
2004 nbytes - (ovp->ov_size + 1 - M_OVERHEAD));
2006 FILL_DEADBEEF((unsigned char*)cp + nbytes,
2007 nb - M_OVERHEAD + RMAGIC_SZ - nbytes);
2009 * Convert amount of memory requested into
2010 * closest block size stored in hash buckets
2011 * which satisfies request. Account for
2012 * space used per block for accounting.
2014 nbytes += M_OVERHEAD;
2015 ovp->ov_size = nbytes - 1;
2016 if ((i = nbytes & (RMAGIC_SZ-1))) {
2018 while (i--) /* nbytes - RMAGIC_SZ is end of alloced area */
2019 ((caddr_t)ovp + nbytes - RMAGIC_SZ)[i]
2022 /* Same at RMAGIC_SZ-aligned RMAGIC */
2023 nbytes = (nbytes + (RMAGIC_SZ-1)) & ~(RMAGIC_SZ - 1);
2024 ((u_int *)((caddr_t)ovp + nbytes))[-1] = RMAGIC;
2028 DEBUG_m(PerlIO_printf(Perl_debug_log,
2029 "0x%"UVxf": (%05lu) realloc %ld bytes inplace\n",
2030 PTR2UV(res),(unsigned long)(PL_an++),
2032 } else if (incr == 1 && (cp - M_OVERHEAD == last_op)
2033 && (onb > (1 << LOG_OF_MIN_ARENA))) {
2034 MEM_SIZE require, newarena = nbytes, pow;
2037 POW2_OPTIMIZE_ADJUST(newarena);
2038 newarena = newarena + M_OVERHEAD;
2039 /* newarena = (newarena + 3) &~ 3; */
2040 shiftr = (newarena - 1) >> LOG_OF_MIN_ARENA;
2041 pow = LOG_OF_MIN_ARENA + 1;
2042 /* apart from this loop, this is O(1) */
2043 while (shiftr >>= 1)
2045 newarena = (1 << pow) + POW2_OPTIMIZE_SURPLUS(pow * BUCKETS_PER_POW2);
2046 require = newarena - onb - M_OVERHEAD;
2049 if (cp - M_OVERHEAD == last_op /* We *still* are the last chunk */
2050 && getpages_adjacent(require)) {
2051 #ifdef DEBUGGING_MSTATS
2053 nmalloc[pow * BUCKETS_PER_POW2]++;
2055 if (pow * BUCKETS_PER_POW2 > (MEM_SIZE)max_bucket)
2056 max_bucket = pow * BUCKETS_PER_POW2;
2057 *(cp - M_OVERHEAD) = pow * BUCKETS_PER_POW2; /* Fill index. */
2066 DEBUG_m(PerlIO_printf(Perl_debug_log,
2067 "0x%"UVxf": (%05lu) realloc %ld bytes the hard way\n",
2068 PTR2UV(cp),(unsigned long)(PL_an++),
2070 if ((res = (char*)Perl_malloc(nbytes)) == NULL)
2072 if (cp != res) /* common optimization */
2073 Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char);
2076 return ((Malloc_t)res);
2080 Perl_calloc(size_t elements, size_t size)
2082 long sz = elements * size;
2083 Malloc_t p = Perl_malloc(sz);
2086 memset((void*)p, 0, sz);
2092 Perl_strdup(const char *s)
2094 MEM_SIZE l = strlen(s);
2095 char *s1 = (char *)Perl_malloc(l+1);
2097 return (char *)CopyD(s, s1, (MEM_SIZE)(l+1), char);
2101 Perl_putenv(char *a)
2103 /* Sometimes system's putenv conflicts with my_setenv() - this is system
2104 malloc vs Perl's free(). */
2111 while (*val && *val != '=')
2116 if (l < sizeof(buf))
2119 var = (char *)Perl_malloc(l + 1);
2120 Copy(a, var, l, char);
2122 my_setenv(var, val+1);
2129 Perl_malloced_size(void *p)
2131 union overhead * const ovp = (union overhead *)
2132 ((caddr_t)p - sizeof (union overhead) * CHUNK_SHIFT);
2133 const int bucket = OV_INDEX(ovp);
2135 PERL_ARGS_ASSERT_MALLOCED_SIZE;
2138 /* The caller wants to have a complete control over the chunk,
2139 disable the memory checking inside the chunk. */
2140 if (bucket <= MAX_SHORT_BUCKET) {
2141 const MEM_SIZE size = BUCKET_SIZE_REAL(bucket);
2142 ovp->ov_size = size + M_OVERHEAD - 1;
2143 *((u_int *)((caddr_t)ovp + size + M_OVERHEAD - RMAGIC_SZ)) = RMAGIC;
2146 return BUCKET_SIZE_REAL(bucket);
2151 Perl_malloc_good_size(size_t wanted)
2153 return BUCKET_SIZE_REAL(adjust_size_and_find_bucket(&wanted));
2156 # ifdef BUCKETS_ROOT2
2157 # define MIN_EVEN_REPORT 6
2159 # define MIN_EVEN_REPORT MIN_BUCKET
2163 Perl_get_mstats(pTHX_ perl_mstats_t *buf, int buflen, int level)
2165 #ifdef DEBUGGING_MSTATS
2168 struct chunk_chain_s* nextchain;
2170 PERL_ARGS_ASSERT_GET_MSTATS;
2172 buf->topbucket = buf->topbucket_ev = buf->topbucket_odd
2173 = buf->totfree = buf->total = buf->total_chain = 0;
2175 buf->minbucket = MIN_BUCKET;
2177 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
2178 for (j = 0, p = nextf[i]; p; p = p->ov_next, j++)
2182 buf->ntotal[i] = nmalloc[i];
2184 buf->totfree += j * BUCKET_SIZE_REAL(i);
2185 buf->total += nmalloc[i] * BUCKET_SIZE_REAL(i);
2187 i % 2 ? (buf->topbucket_odd = i) : (buf->topbucket_ev = i);
2191 nextchain = chunk_chain;
2193 buf->total_chain += nextchain->size;
2194 nextchain = nextchain->next;
2196 buf->total_sbrk = goodsbrk + sbrk_slack;
2198 buf->sbrk_good = sbrk_goodness;
2199 buf->sbrk_slack = sbrk_slack;
2200 buf->start_slack = start_slack;
2201 buf->sbrked_remains = sbrked_remains;
2203 buf->nbuckets = NBUCKETS;
2205 for (i = MIN_BUCKET ; i < NBUCKETS; i++) {
2208 buf->bucket_mem_size[i] = BUCKET_SIZE_NO_SURPLUS(i);
2209 buf->bucket_available_size[i] = BUCKET_SIZE_REAL(i);
2212 #else /* defined DEBUGGING_MSTATS */
2213 PerlIO_printf(Perl_error_log, "perl not compiled with DEBUGGING_MSTATS\n");
2214 #endif /* defined DEBUGGING_MSTATS */
2215 return 0; /* XXX unused */
2218 * mstats - print out statistics about malloc
2220 * Prints two lines of numbers, one showing the length of the free list
2221 * for each size category, the second showing the number of mallocs -
2222 * frees for each size category.
2225 Perl_dump_mstats(pTHX_ const char *s)
2227 #ifdef DEBUGGING_MSTATS
2229 perl_mstats_t buffer;
2233 PERL_ARGS_ASSERT_DUMP_MSTATS;
2237 get_mstats(&buffer, NBUCKETS, 0);
2240 PerlIO_printf(Perl_error_log,
2241 "Memory allocation statistics %s (buckets %"IVdf"(%"IVdf")..%"IVdf"(%"IVdf")\n",
2243 (IV)BUCKET_SIZE_REAL(MIN_BUCKET),
2244 (IV)BUCKET_SIZE_NO_SURPLUS(MIN_BUCKET),
2245 (IV)BUCKET_SIZE_REAL(buffer.topbucket),
2246 (IV)BUCKET_SIZE_NO_SURPLUS(buffer.topbucket));
2247 PerlIO_printf(Perl_error_log, "%8"IVdf" free:", buffer.totfree);
2248 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
2249 PerlIO_printf(Perl_error_log,
2250 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2252 : ((i < 12*BUCKETS_PER_POW2) ? " %3"UVuf : " %"UVuf)),
2255 #ifdef BUCKETS_ROOT2
2256 PerlIO_printf(Perl_error_log, "\n\t ");
2257 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
2258 PerlIO_printf(Perl_error_log,
2259 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2261 : ((i < 12*BUCKETS_PER_POW2) ? " %3"UVuf : " %"UVuf)),
2265 PerlIO_printf(Perl_error_log, "\n%8"IVdf" used:", buffer.total - buffer.totfree);
2266 for (i = MIN_EVEN_REPORT; i <= buffer.topbucket; i += BUCKETS_PER_POW2) {
2267 PerlIO_printf(Perl_error_log,
2268 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2270 : ((i < 12*BUCKETS_PER_POW2) ? " %3"IVdf : " %"IVdf)),
2271 buffer.ntotal[i] - buffer.nfree[i]);
2273 #ifdef BUCKETS_ROOT2
2274 PerlIO_printf(Perl_error_log, "\n\t ");
2275 for (i = MIN_BUCKET + 1; i <= buffer.topbucket_odd; i += BUCKETS_PER_POW2) {
2276 PerlIO_printf(Perl_error_log,
2277 ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2)
2279 : ((i < 12*BUCKETS_PER_POW2) ? " %3"IVdf : " %"IVdf)),
2280 buffer.ntotal[i] - buffer.nfree[i]);
2283 PerlIO_printf(Perl_error_log, "\nTotal sbrk(): %"IVdf"/%"IVdf":%"IVdf". Odd ends: pad+heads+chain+tail: %"IVdf"+%"IVdf"+%"IVdf"+%"IVdf".\n",
2284 buffer.total_sbrk, buffer.sbrks, buffer.sbrk_good,
2285 buffer.sbrk_slack, buffer.start_slack,
2286 buffer.total_chain, buffer.sbrked_remains);
2287 #else /* DEBUGGING_MSTATS */
2288 PerlIO_printf(Perl_error_log, "%s: perl not compiled with DEBUGGING_MSTATS\n",s);
2289 #endif /* DEBUGGING_MSTATS */
2292 #ifdef USE_PERL_SBRK
2294 # if defined(PURIFY)
2295 # define PERL_SBRK_VIA_MALLOC
2298 # ifdef PERL_SBRK_VIA_MALLOC
2300 /* it may seem schizophrenic to use perl's malloc and let it call system */
2301 /* malloc, the reason for that is only the 3.2 version of the OS that had */
2302 /* frequent core dumps within nxzonefreenolock. This sbrk routine put an */
2303 /* end to the cores */
2305 # ifndef SYSTEM_ALLOC
2306 # define SYSTEM_ALLOC(a) malloc(a)
2308 # ifndef SYSTEM_ALLOC_ALIGNMENT
2309 # define SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES
2312 # endif /* PERL_SBRK_VIA_MALLOC */
2314 static IV Perl_sbrk_oldchunk;
2315 static long Perl_sbrk_oldsize;
2317 # define PERLSBRK_32_K (1<<15)
2318 # define PERLSBRK_64_K (1<<16)
2326 if (!size) return 0;
2327 reqsize = size; /* just for the DEBUG_m statement */
2329 size = (size + 0x7ff) & ~0x7ff;
2331 if (size <= Perl_sbrk_oldsize) {
2332 got = Perl_sbrk_oldchunk;
2333 Perl_sbrk_oldchunk += size;
2334 Perl_sbrk_oldsize -= size;
2336 if (size >= PERLSBRK_32_K) {
2339 size = PERLSBRK_64_K;
2342 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2343 size += NEEDED_ALIGNMENT - SYSTEM_ALLOC_ALIGNMENT;
2345 got = (IV)SYSTEM_ALLOC(size);
2346 # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT
2347 got = (got + NEEDED_ALIGNMENT - 1) & ~(NEEDED_ALIGNMENT - 1);
2350 /* Chunk is small, register the rest for future allocs. */
2351 Perl_sbrk_oldchunk = got + reqsize;
2352 Perl_sbrk_oldsize = size - reqsize;
2356 DEBUG_m(PerlIO_printf(Perl_debug_log, "sbrk malloc size %ld (reqsize %ld), left size %ld, give addr 0x%"UVxf"\n",
2357 size, reqsize, Perl_sbrk_oldsize, PTR2UV(got)));
2362 #endif /* ! defined USE_PERL_SBRK */
2366 * c-indentation-style: bsd
2368 * indent-tabs-mode: nil
2371 * ex: set ts=8 sts=4 sw=4 et: