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1 | /* malloc.c |
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2 | * |
8d063cd8 |
3 | */ |
4 | |
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5 | /* |
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6 | Here are some notes on configuring Perl's malloc. (For non-perl |
7 | usage see below.) |
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8 | |
9 | There are two macros which serve as bulk disablers of advanced |
10 | features of this malloc: NO_FANCY_MALLOC, PLAIN_MALLOC (undef by |
11 | default). Look in the list of default values below to understand |
12 | their exact effect. Defining NO_FANCY_MALLOC returns malloc.c to the |
13 | state of the malloc in Perl 5.004. Additionally defining PLAIN_MALLOC |
14 | returns it to the state as of Perl 5.000. |
15 | |
16 | Note that some of the settings below may be ignored in the code based |
17 | on values of other macros. The PERL_CORE symbol is only defined when |
18 | perl itself is being compiled (so malloc can make some assumptions |
19 | about perl's facilities being available to it). |
20 | |
21 | Each config option has a short description, followed by its name, |
22 | default value, and a comment about the default (if applicable). Some |
23 | options take a precise value, while the others are just boolean. |
24 | The boolean ones are listed first. |
25 | |
26 | # Enable code for an emergency memory pool in $^M. See perlvar.pod |
27 | # for a description of $^M. |
28 | PERL_EMERGENCY_SBRK (!PLAIN_MALLOC && PERL_CORE) |
29 | |
30 | # Enable code for printing memory statistics. |
31 | DEBUGGING_MSTATS (!PLAIN_MALLOC && PERL_CORE) |
32 | |
33 | # Move allocation info for small buckets into separate areas. |
34 | # Memory optimization (especially for small allocations, of the |
35 | # less than 64 bytes). Since perl usually makes a large number |
36 | # of small allocations, this is usually a win. |
37 | PACK_MALLOC (!PLAIN_MALLOC && !RCHECK) |
38 | |
39 | # Add one page to big powers of two when calculating bucket size. |
40 | # This is targeted at big allocations, as are common in image |
41 | # processing. |
42 | TWO_POT_OPTIMIZE !PLAIN_MALLOC |
43 | |
44 | # Use intermediate bucket sizes between powers-of-two. This is |
45 | # generally a memory optimization, and a (small) speed pessimization. |
46 | BUCKETS_ROOT2 !NO_FANCY_MALLOC |
47 | |
48 | # Do not check small deallocations for bad free(). Memory |
49 | # and speed optimization, error reporting pessimization. |
50 | IGNORE_SMALL_BAD_FREE (!NO_FANCY_MALLOC && !RCHECK) |
51 | |
52 | # Use table lookup to decide in which bucket a given allocation will go. |
53 | SMALL_BUCKET_VIA_TABLE !NO_FANCY_MALLOC |
54 | |
38ac2dc8 |
55 | # Use a perl-defined sbrk() instead of the (presumably broken or |
56 | # missing) system-supplied sbrk(). |
57 | USE_PERL_SBRK undef |
58 | |
59 | # Use system malloc() (or calloc() etc.) to emulate sbrk(). Normally |
60 | # only used with broken sbrk()s. |
87c6202a |
61 | PERL_SBRK_VIA_MALLOC undef |
62 | |
38ac2dc8 |
63 | # Which allocator to use if PERL_SBRK_VIA_MALLOC |
64 | SYSTEM_ALLOC(a) malloc(a) |
65 | |
9ee81ef6 |
66 | # Minimal alignment (in bytes, should be a power of 2) of SYSTEM_ALLOC |
5bbd1ef5 |
67 | SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES |
68 | |
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69 | # Disable memory overwrite checking with DEBUGGING. Memory and speed |
70 | # optimization, error reporting pessimization. |
71 | NO_RCHECK undef |
72 | |
73 | # Enable memory overwrite checking with DEBUGGING. Memory and speed |
74 | # pessimization, error reporting optimization |
75 | RCHECK (DEBUGGING && !NO_RCHECK) |
76 | |
77 | # Failed allocations bigger than this size croak (if |
78 | # PERL_EMERGENCY_SBRK is enabled) without touching $^M. See |
79 | # perlvar.pod for a description of $^M. |
80 | BIG_SIZE (1<<16) # 64K |
81 | |
82 | # Starting from this power of two, add an extra page to the |
83 | # size of the bucket. This enables optimized allocations of sizes |
84 | # close to powers of 2. Note that the value is indexed at 0. |
85 | FIRST_BIG_POW2 15 # 32K, 16K is used too often |
86 | |
87 | # Estimate of minimal memory footprint. malloc uses this value to |
88 | # request the most reasonable largest blocks of memory from the system. |
89 | FIRST_SBRK (48*1024) |
90 | |
91 | # Round up sbrk()s to multiples of this. |
92 | MIN_SBRK 2048 |
93 | |
94 | # Round up sbrk()s to multiples of this percent of footprint. |
95 | MIN_SBRK_FRAC 3 |
96 | |
97 | # Add this much memory to big powers of two to get the bucket size. |
98 | PERL_PAGESIZE 4096 |
99 | |
100 | # This many sbrk() discontinuities should be tolerated even |
101 | # from the start without deciding that sbrk() is usually |
102 | # discontinuous. |
103 | SBRK_ALLOW_FAILURES 3 |
104 | |
105 | # This many continuous sbrk()s compensate for one discontinuous one. |
106 | SBRK_FAILURE_PRICE 50 |
107 | |
28ac10b1 |
108 | # Some configurations may ask for 12-byte-or-so allocations which |
109 | # require 8-byte alignment (?!). In such situation one needs to |
110 | # define this to disable 12-byte bucket (will increase memory footprint) |
111 | STRICT_ALIGNMENT undef |
112 | |
87c6202a |
113 | This implementation assumes that calling PerlIO_printf() does not |
114 | result in any memory allocation calls (used during a panic). |
115 | |
116 | */ |
117 | |
741df71a |
118 | /* |
119 | If used outside of Perl environment, it may be useful to redefine |
120 | the following macros (listed below with defaults): |
121 | |
122 | # Type of address returned by allocation functions |
123 | Malloc_t void * |
124 | |
125 | # Type of size argument for allocation functions |
126 | MEM_SIZE unsigned long |
127 | |
128 | # Maximal value in LONG |
129 | LONG_MAX 0x7FFFFFFF |
130 | |
131 | # Unsigned integer type big enough to keep a pointer |
132 | UV unsigned long |
133 | |
134 | # Type of pointer with 1-byte granularity |
135 | caddr_t char * |
136 | |
137 | # Type returned by free() |
138 | Free_t void |
139 | |
5bbd1ef5 |
140 | # Very fatal condition reporting function (cannot call any ) |
141 | fatalcroak(arg) write(2,arg,strlen(arg)) + exit(2) |
142 | |
741df71a |
143 | # Fatal error reporting function |
144 | croak(format, arg) warn(idem) + exit(1) |
145 | |
146 | # Error reporting function |
147 | warn(format, arg) fprintf(stderr, idem) |
148 | |
149 | # Locking/unlocking for MT operation |
64f996d1 |
150 | MALLOC_LOCK MUTEX_LOCK(&PL_malloc_mutex) |
151 | MALLOC_UNLOCK MUTEX_UNLOCK(&PL_malloc_mutex) |
741df71a |
152 | |
153 | # Locking/unlocking mutex for MT operation |
154 | MUTEX_LOCK(l) void |
155 | MUTEX_UNLOCK(l) void |
156 | */ |
157 | |
e8bc2b5c |
158 | #ifndef NO_FANCY_MALLOC |
159 | # ifndef SMALL_BUCKET_VIA_TABLE |
160 | # define SMALL_BUCKET_VIA_TABLE |
161 | # endif |
162 | # ifndef BUCKETS_ROOT2 |
163 | # define BUCKETS_ROOT2 |
164 | # endif |
165 | # ifndef IGNORE_SMALL_BAD_FREE |
166 | # define IGNORE_SMALL_BAD_FREE |
167 | # endif |
3562ef9b |
168 | #endif |
169 | |
e8bc2b5c |
170 | #ifndef PLAIN_MALLOC /* Bulk enable features */ |
171 | # ifndef PACK_MALLOC |
172 | # define PACK_MALLOC |
173 | # endif |
174 | # ifndef TWO_POT_OPTIMIZE |
175 | # define TWO_POT_OPTIMIZE |
176 | # endif |
d720c441 |
177 | # if defined(PERL_CORE) && !defined(PERL_EMERGENCY_SBRK) |
178 | # define PERL_EMERGENCY_SBRK |
e8bc2b5c |
179 | # endif |
180 | # if defined(PERL_CORE) && !defined(DEBUGGING_MSTATS) |
181 | # define DEBUGGING_MSTATS |
182 | # endif |
183 | #endif |
184 | |
185 | #define MIN_BUC_POW2 (sizeof(void*) > 4 ? 3 : 2) /* Allow for 4-byte arena. */ |
186 | #define MIN_BUCKET (MIN_BUC_POW2 * BUCKETS_PER_POW2) |
187 | |
61ae2fbf |
188 | #if !(defined(I286) || defined(atarist) || defined(__MINT__)) |
e8bc2b5c |
189 | /* take 2k unless the block is bigger than that */ |
190 | # define LOG_OF_MIN_ARENA 11 |
191 | #else |
192 | /* take 16k unless the block is bigger than that |
193 | (80286s like large segments!), probably good on the atari too */ |
194 | # define LOG_OF_MIN_ARENA 14 |
195 | #endif |
196 | |
8d063cd8 |
197 | #ifndef lint |
1944739a |
198 | # if defined(DEBUGGING) && !defined(NO_RCHECK) |
199 | # define RCHECK |
200 | # endif |
e8bc2b5c |
201 | # if defined(RCHECK) && defined(IGNORE_SMALL_BAD_FREE) |
202 | # undef IGNORE_SMALL_BAD_FREE |
203 | # endif |
8d063cd8 |
204 | /* |
205 | * malloc.c (Caltech) 2/21/82 |
206 | * Chris Kingsley, kingsley@cit-20. |
207 | * |
208 | * This is a very fast storage allocator. It allocates blocks of a small |
209 | * number of different sizes, and keeps free lists of each size. Blocks that |
210 | * don't exactly fit are passed up to the next larger size. In this |
211 | * implementation, the available sizes are 2^n-4 (or 2^n-12) bytes long. |
cf5c4ad8 |
212 | * If PACK_MALLOC is defined, small blocks are 2^n bytes long. |
8d063cd8 |
213 | * This is designed for use in a program that uses vast quantities of memory, |
741df71a |
214 | * but bombs when it runs out. |
215 | * |
4eb8286e |
216 | * Modifications Copyright Ilya Zakharevich 1996-99. |
741df71a |
217 | * |
218 | * Still very quick, but much more thrifty. (Std config is 10% slower |
219 | * than it was, and takes 67% of old heap size for typical usage.) |
220 | * |
221 | * Allocations of small blocks are now table-driven to many different |
222 | * buckets. Sizes of really big buckets are increased to accomodata |
223 | * common size=power-of-2 blocks. Running-out-of-memory is made into |
224 | * an exception. Deeply configurable and thread-safe. |
225 | * |
8d063cd8 |
226 | */ |
227 | |
d720c441 |
228 | #ifdef PERL_CORE |
229 | # include "EXTERN.h" |
864dbfa3 |
230 | #define PERL_IN_MALLOC_C |
d720c441 |
231 | # include "perl.h" |
232 | #else |
233 | # ifdef PERL_FOR_X2P |
234 | # include "../EXTERN.h" |
235 | # include "../perl.h" |
236 | # else |
237 | # include <stdlib.h> |
238 | # include <stdio.h> |
239 | # include <memory.h> |
240 | # define _(arg) arg |
241 | # ifndef Malloc_t |
242 | # define Malloc_t void * |
243 | # endif |
244 | # ifndef MEM_SIZE |
245 | # define MEM_SIZE unsigned long |
246 | # endif |
247 | # ifndef LONG_MAX |
248 | # define LONG_MAX 0x7FFFFFFF |
249 | # endif |
250 | # ifndef UV |
251 | # define UV unsigned long |
252 | # endif |
253 | # ifndef caddr_t |
254 | # define caddr_t char * |
255 | # endif |
256 | # ifndef Free_t |
257 | # define Free_t void |
258 | # endif |
259 | # define Copy(s,d,n,t) (void)memcpy((char*)(d),(char*)(s), (n) * sizeof(t)) |
260 | # define PerlEnv_getenv getenv |
261 | # define PerlIO_printf fprintf |
262 | # define PerlIO_stderr() stderr |
263 | # endif |
e8bc2b5c |
264 | # ifndef croak /* make depend */ |
741df71a |
265 | # define croak(mess, arg) (warn((mess), (arg)), exit(1)) |
d720c441 |
266 | # endif |
267 | # ifndef warn |
741df71a |
268 | # define warn(mess, arg) fprintf(stderr, (mess), (arg)) |
e8bc2b5c |
269 | # endif |
270 | # ifdef DEBUG_m |
271 | # undef DEBUG_m |
272 | # endif |
273 | # define DEBUG_m(a) |
274 | # ifdef DEBUGGING |
275 | # undef DEBUGGING |
276 | # endif |
277 | #endif |
278 | |
279 | #ifndef MUTEX_LOCK |
280 | # define MUTEX_LOCK(l) |
281 | #endif |
282 | |
283 | #ifndef MUTEX_UNLOCK |
284 | # define MUTEX_UNLOCK(l) |
285 | #endif |
286 | |
741df71a |
287 | #ifndef MALLOC_LOCK |
64f996d1 |
288 | # define MALLOC_LOCK MUTEX_LOCK(&PL_malloc_mutex) |
741df71a |
289 | #endif |
290 | |
291 | #ifndef MALLOC_UNLOCK |
64f996d1 |
292 | # define MALLOC_UNLOCK MUTEX_UNLOCK(&PL_malloc_mutex) |
741df71a |
293 | #endif |
294 | |
5bbd1ef5 |
295 | # ifndef fatalcroak /* make depend */ |
296 | # define fatalcroak(mess) (write(2, (mess), strlen(mess)), exit(2)) |
297 | # endif |
298 | |
760ac839 |
299 | #ifdef DEBUGGING |
e8bc2b5c |
300 | # undef DEBUG_m |
4a33f861 |
301 | # define DEBUG_m(a) if (PL_debug & 128) a |
760ac839 |
302 | #endif |
303 | |
e9397286 |
304 | /* |
305 | * Layout of memory: |
306 | * ~~~~~~~~~~~~~~~~ |
307 | * The memory is broken into "blocks" which occupy multiples of 2K (and |
308 | * generally speaking, have size "close" to a power of 2). The addresses |
309 | * of such *unused* blocks are kept in nextf[i] with big enough i. (nextf |
310 | * is an array of linked lists.) (Addresses of used blocks are not known.) |
311 | * |
312 | * Moreover, since the algorithm may try to "bite" smaller blocks of out |
313 | * of unused bigger ones, there are also regions of "irregular" size, |
314 | * managed separately, by a linked list chunk_chain. |
315 | * |
316 | * The third type of storage is the sbrk()ed-but-not-yet-used space, its |
317 | * end and size are kept in last_sbrk_top and sbrked_remains. |
318 | * |
319 | * Growing blocks "in place": |
320 | * ~~~~~~~~~~~~~~~~~~~~~~~~~ |
321 | * The address of the block with the greatest address is kept in last_op |
322 | * (if not known, last_op is 0). If it is known that the memory above |
323 | * last_op is not continuous, or contains a chunk from chunk_chain, |
324 | * last_op is set to 0. |
325 | * |
326 | * The chunk with address last_op may be grown by expanding into |
327 | * sbrk()ed-but-not-yet-used space, or trying to sbrk() more continuous |
328 | * memory. |
329 | * |
330 | * Management of last_op: |
331 | * ~~~~~~~~~~~~~~~~~~~~~ |
332 | * |
333 | * free() never changes the boundaries of blocks, so is not relevant. |
334 | * |
335 | * The only way realloc() may change the boundaries of blocks is if it |
336 | * grows a block "in place". However, in the case of success such a |
337 | * chunk is automatically last_op, and it remains last_op. In the case |
338 | * of failure getpages_adjacent() clears last_op. |
339 | * |
340 | * malloc() may change blocks by calling morecore() only. |
341 | * |
342 | * morecore() may create new blocks by: |
343 | * a) biting pieces from chunk_chain (cannot create one above last_op); |
344 | * b) biting a piece from an unused block (if block was last_op, this |
345 | * may create a chunk from chain above last_op, thus last_op is |
346 | * invalidated in such a case). |
347 | * c) biting of sbrk()ed-but-not-yet-used space. This creates |
348 | * a block which is last_op. |
349 | * d) Allocating new pages by calling getpages(); |
350 | * |
351 | * getpages() creates a new block. It marks last_op at the bottom of |
352 | * the chunk of memory it returns. |
353 | * |
354 | * Active pages footprint: |
355 | * ~~~~~~~~~~~~~~~~~~~~~~ |
356 | * Note that we do not need to traverse the lists in nextf[i], just take |
357 | * the first element of this list. However, we *need* to traverse the |
358 | * list in chunk_chain, but most the time it should be a very short one, |
359 | * so we do not step on a lot of pages we are not going to use. |
360 | * |
361 | * Flaws: |
362 | * ~~~~~ |
363 | * get_from_bigger_buckets(): forget to increment price => Quite |
364 | * aggressive. |
365 | */ |
366 | |
135863df |
367 | /* I don't much care whether these are defined in sys/types.h--LAW */ |
368 | |
369 | #define u_char unsigned char |
370 | #define u_int unsigned int |
e8bc2b5c |
371 | |
372 | #ifdef HAS_QUAD |
373 | # define u_bigint UV /* Needs to eat *void. */ |
374 | #else /* needed? */ |
375 | # define u_bigint unsigned long /* Needs to eat *void. */ |
376 | #endif |
377 | |
135863df |
378 | #define u_short unsigned short |
8d063cd8 |
379 | |
cf5c4ad8 |
380 | /* 286 and atarist like big chunks, which gives too much overhead. */ |
61ae2fbf |
381 | #if (defined(RCHECK) || defined(I286) || defined(atarist) || defined(__MINT__)) && defined(PACK_MALLOC) |
e8bc2b5c |
382 | # undef PACK_MALLOC |
cf5c4ad8 |
383 | #endif |
384 | |
8d063cd8 |
385 | /* |
cf5c4ad8 |
386 | * The description below is applicable if PACK_MALLOC is not defined. |
387 | * |
8d063cd8 |
388 | * The overhead on a block is at least 4 bytes. When free, this space |
389 | * contains a pointer to the next free block, and the bottom two bits must |
390 | * be zero. When in use, the first byte is set to MAGIC, and the second |
391 | * byte is the size index. The remaining bytes are for alignment. |
392 | * If range checking is enabled and the size of the block fits |
393 | * in two bytes, then the top two bytes hold the size of the requested block |
394 | * plus the range checking words, and the header word MINUS ONE. |
395 | */ |
396 | union overhead { |
397 | union overhead *ov_next; /* when free */ |
85e6fe83 |
398 | #if MEM_ALIGNBYTES > 4 |
c623bd54 |
399 | double strut; /* alignment problems */ |
a687059c |
400 | #endif |
8d063cd8 |
401 | struct { |
402 | u_char ovu_magic; /* magic number */ |
403 | u_char ovu_index; /* bucket # */ |
404 | #ifdef RCHECK |
405 | u_short ovu_size; /* actual block size */ |
406 | u_int ovu_rmagic; /* range magic number */ |
407 | #endif |
408 | } ovu; |
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 |
413 | }; |
414 | |
415 | #define MAGIC 0xff /* magic # on accounting info */ |
416 | #define RMAGIC 0x55555555 /* magic # on range info */ |
e8bc2b5c |
417 | #define RMAGIC_C 0x55 /* magic # on range info */ |
418 | |
8d063cd8 |
419 | #ifdef RCHECK |
c2a5c2d2 |
420 | # define RSLOP sizeof (u_int) |
421 | # ifdef TWO_POT_OPTIMIZE |
e8bc2b5c |
422 | # define MAX_SHORT_BUCKET (12 * BUCKETS_PER_POW2) |
c2a5c2d2 |
423 | # else |
e8bc2b5c |
424 | # define MAX_SHORT_BUCKET (13 * BUCKETS_PER_POW2) |
c2a5c2d2 |
425 | # endif |
8d063cd8 |
426 | #else |
c2a5c2d2 |
427 | # define RSLOP 0 |
8d063cd8 |
428 | #endif |
429 | |
e8bc2b5c |
430 | #if !defined(PACK_MALLOC) && defined(BUCKETS_ROOT2) |
431 | # undef BUCKETS_ROOT2 |
432 | #endif |
433 | |
434 | #ifdef BUCKETS_ROOT2 |
435 | # define BUCKET_TABLE_SHIFT 2 |
436 | # define BUCKET_POW2_SHIFT 1 |
437 | # define BUCKETS_PER_POW2 2 |
438 | #else |
439 | # define BUCKET_TABLE_SHIFT MIN_BUC_POW2 |
440 | # define BUCKET_POW2_SHIFT 0 |
441 | # define BUCKETS_PER_POW2 1 |
442 | #endif |
443 | |
274c7500 |
444 | #if !defined(MEM_ALIGNBYTES) || ((MEM_ALIGNBYTES > 4) && !defined(STRICT_ALIGNMENT)) |
445 | /* Figure out the alignment of void*. */ |
446 | struct aligner { |
447 | char c; |
448 | void *p; |
449 | }; |
450 | # define ALIGN_SMALL ((int)((caddr_t)&(((struct aligner*)0)->p))) |
451 | #else |
452 | # define ALIGN_SMALL MEM_ALIGNBYTES |
453 | #endif |
454 | |
455 | #define IF_ALIGN_8(yes,no) ((ALIGN_SMALL>4) ? (yes) : (no)) |
456 | |
e8bc2b5c |
457 | #ifdef BUCKETS_ROOT2 |
458 | # define MAX_BUCKET_BY_TABLE 13 |
459 | static u_short buck_size[MAX_BUCKET_BY_TABLE + 1] = |
460 | { |
461 | 0, 0, 0, 0, 4, 4, 8, 12, 16, 24, 32, 48, 64, 80, |
462 | }; |
463 | # define BUCKET_SIZE(i) ((i) % 2 ? buck_size[i] : (1 << ((i) >> BUCKET_POW2_SHIFT))) |
464 | # define BUCKET_SIZE_REAL(i) ((i) <= MAX_BUCKET_BY_TABLE \ |
465 | ? buck_size[i] \ |
466 | : ((1 << ((i) >> BUCKET_POW2_SHIFT)) \ |
467 | - MEM_OVERHEAD(i) \ |
468 | + POW2_OPTIMIZE_SURPLUS(i))) |
469 | #else |
470 | # define BUCKET_SIZE(i) (1 << ((i) >> BUCKET_POW2_SHIFT)) |
471 | # define BUCKET_SIZE_REAL(i) (BUCKET_SIZE(i) - MEM_OVERHEAD(i) + POW2_OPTIMIZE_SURPLUS(i)) |
472 | #endif |
473 | |
474 | |
cf5c4ad8 |
475 | #ifdef PACK_MALLOC |
e8bc2b5c |
476 | /* In this case it is assumed that if we do sbrk() in 2K units, we |
477 | * will get 2K aligned arenas (at least after some initial |
478 | * alignment). The bucket number of the given subblock is on the start |
479 | * of 2K arena which contains the subblock. Several following bytes |
480 | * contain the magic numbers for the subblocks in the block. |
cf5c4ad8 |
481 | * |
482 | * Sizes of chunks are powers of 2 for chunks in buckets <= |
483 | * MAX_PACKED, after this they are (2^n - sizeof(union overhead)) (to |
484 | * get alignment right). |
485 | * |
e8bc2b5c |
486 | * Consider an arena for 2^n with n>MAX_PACKED. We suppose that |
487 | * starts of all the chunks in a 2K arena are in different |
488 | * 2^n-byte-long chunks. If the top of the last chunk is aligned on a |
489 | * boundary of 2K block, this means that sizeof(union |
490 | * overhead)*"number of chunks" < 2^n, or sizeof(union overhead)*2K < |
491 | * 4^n, or n > 6 + log2(sizeof()/2)/2, since a chunk of size 2^n - |
492 | * overhead is used. Since this rules out n = 7 for 8 byte alignment, |
493 | * we specialcase allocation of the first of 16 128-byte-long chunks. |
cf5c4ad8 |
494 | * |
495 | * Note that with the above assumption we automatically have enough |
496 | * place for MAGIC at the start of 2K block. Note also that we |
e8bc2b5c |
497 | * overlay union overhead over the chunk, thus the start of small chunks |
498 | * is immediately overwritten after freeing. */ |
499 | # define MAX_PACKED_POW2 6 |
500 | # define MAX_PACKED (MAX_PACKED_POW2 * BUCKETS_PER_POW2 + BUCKET_POW2_SHIFT) |
501 | # define MAX_POW2_ALGO ((1<<(MAX_PACKED_POW2 + 1)) - M_OVERHEAD) |
502 | # define TWOK_MASK ((1<<LOG_OF_MIN_ARENA) - 1) |
503 | # define TWOK_MASKED(x) ((u_bigint)(x) & ~TWOK_MASK) |
504 | # define TWOK_SHIFT(x) ((u_bigint)(x) & TWOK_MASK) |
cf5c4ad8 |
505 | # define OV_INDEXp(block) ((u_char*)(TWOK_MASKED(block))) |
506 | # define OV_INDEX(block) (*OV_INDEXp(block)) |
507 | # define OV_MAGIC(block,bucket) (*(OV_INDEXp(block) + \ |
e8bc2b5c |
508 | (TWOK_SHIFT(block)>> \ |
509 | (bucket>>BUCKET_POW2_SHIFT)) + \ |
510 | (bucket >= MIN_NEEDS_SHIFT ? 1 : 0))) |
511 | /* A bucket can have a shift smaller than it size, we need to |
512 | shift its magic number so it will not overwrite index: */ |
513 | # ifdef BUCKETS_ROOT2 |
514 | # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2 - 1) /* Shift 80 greater than chunk 64. */ |
515 | # else |
516 | # define MIN_NEEDS_SHIFT (7*BUCKETS_PER_POW2) /* Shift 128 greater than chunk 32. */ |
517 | # endif |
cf5c4ad8 |
518 | # define CHUNK_SHIFT 0 |
519 | |
e8bc2b5c |
520 | /* Number of active buckets of given ordinal. */ |
521 | #ifdef IGNORE_SMALL_BAD_FREE |
522 | #define FIRST_BUCKET_WITH_CHECK (6 * BUCKETS_PER_POW2) /* 64 */ |
523 | # define N_BLKS(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \ |
524 | ? ((1<<LOG_OF_MIN_ARENA) - 1)/BUCKET_SIZE(bucket) \ |
525 | : n_blks[bucket] ) |
526 | #else |
527 | # define N_BLKS(bucket) n_blks[bucket] |
528 | #endif |
529 | |
530 | static u_short n_blks[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] = |
531 | { |
532 | # if BUCKETS_PER_POW2==1 |
533 | 0, 0, |
534 | (MIN_BUC_POW2==2 ? 384 : 0), |
535 | 224, 120, 62, 31, 16, 8, 4, 2 |
536 | # else |
537 | 0, 0, 0, 0, |
538 | (MIN_BUC_POW2==2 ? 384 : 0), (MIN_BUC_POW2==2 ? 384 : 0), /* 4, 4 */ |
539 | 224, 149, 120, 80, 62, 41, 31, 25, 16, 16, 8, 8, 4, 4, 2, 2 |
540 | # endif |
541 | }; |
542 | |
543 | /* Shift of the first bucket with the given ordinal inside 2K chunk. */ |
544 | #ifdef IGNORE_SMALL_BAD_FREE |
545 | # define BLK_SHIFT(bucket) ( (bucket) < FIRST_BUCKET_WITH_CHECK \ |
546 | ? ((1<<LOG_OF_MIN_ARENA) \ |
547 | - BUCKET_SIZE(bucket) * N_BLKS(bucket)) \ |
548 | : blk_shift[bucket]) |
549 | #else |
550 | # define BLK_SHIFT(bucket) blk_shift[bucket] |
551 | #endif |
552 | |
553 | static u_short blk_shift[LOG_OF_MIN_ARENA * BUCKETS_PER_POW2] = |
554 | { |
555 | # if BUCKETS_PER_POW2==1 |
556 | 0, 0, |
557 | (MIN_BUC_POW2==2 ? 512 : 0), |
558 | 256, 128, 64, 64, /* 8 to 64 */ |
559 | 16*sizeof(union overhead), |
560 | 8*sizeof(union overhead), |
561 | 4*sizeof(union overhead), |
562 | 2*sizeof(union overhead), |
563 | # else |
564 | 0, 0, 0, 0, |
565 | (MIN_BUC_POW2==2 ? 512 : 0), (MIN_BUC_POW2==2 ? 512 : 0), |
566 | 256, 260, 128, 128, 64, 80, 64, 48, /* 8 to 96 */ |
567 | 16*sizeof(union overhead), 16*sizeof(union overhead), |
568 | 8*sizeof(union overhead), 8*sizeof(union overhead), |
569 | 4*sizeof(union overhead), 4*sizeof(union overhead), |
570 | 2*sizeof(union overhead), 2*sizeof(union overhead), |
571 | # endif |
572 | }; |
cf5c4ad8 |
573 | |
5bbd1ef5 |
574 | # define NEEDED_ALIGNMENT 0x800 /* 2k boundaries */ |
575 | # define WANTED_ALIGNMENT 0x800 /* 2k boundaries */ |
576 | |
cf5c4ad8 |
577 | #else /* !PACK_MALLOC */ |
578 | |
579 | # define OV_MAGIC(block,bucket) (block)->ov_magic |
580 | # define OV_INDEX(block) (block)->ov_index |
581 | # define CHUNK_SHIFT 1 |
e8bc2b5c |
582 | # define MAX_PACKED -1 |
5bbd1ef5 |
583 | # define NEEDED_ALIGNMENT MEM_ALIGNBYTES |
584 | # define WANTED_ALIGNMENT 0x400 /* 1k boundaries */ |
585 | |
cf5c4ad8 |
586 | #endif /* !PACK_MALLOC */ |
587 | |
e8bc2b5c |
588 | #define M_OVERHEAD (sizeof(union overhead) + RSLOP) |
589 | |
590 | #ifdef PACK_MALLOC |
591 | # define MEM_OVERHEAD(bucket) \ |
592 | (bucket <= MAX_PACKED ? 0 : M_OVERHEAD) |
593 | # ifdef SMALL_BUCKET_VIA_TABLE |
594 | # define START_SHIFTS_BUCKET ((MAX_PACKED_POW2 + 1) * BUCKETS_PER_POW2) |
595 | # define START_SHIFT MAX_PACKED_POW2 |
596 | # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */ |
597 | # define SIZE_TABLE_MAX 80 |
598 | # else |
599 | # define SIZE_TABLE_MAX 64 |
600 | # endif |
601 | static char bucket_of[] = |
602 | { |
603 | # ifdef BUCKETS_ROOT2 /* Chunks of size 3*2^n. */ |
604 | /* 0 to 15 in 4-byte increments. */ |
605 | (sizeof(void*) > 4 ? 6 : 5), /* 4/8, 5-th bucket for better reports */ |
606 | 6, /* 8 */ |
274c7500 |
607 | IF_ALIGN_8(8,7), 8, /* 16/12, 16 */ |
e8bc2b5c |
608 | 9, 9, 10, 10, /* 24, 32 */ |
609 | 11, 11, 11, 11, /* 48 */ |
610 | 12, 12, 12, 12, /* 64 */ |
611 | 13, 13, 13, 13, /* 80 */ |
612 | 13, 13, 13, 13 /* 80 */ |
613 | # else /* !BUCKETS_ROOT2 */ |
614 | /* 0 to 15 in 4-byte increments. */ |
615 | (sizeof(void*) > 4 ? 3 : 2), |
616 | 3, |
617 | 4, 4, |
618 | 5, 5, 5, 5, |
619 | 6, 6, 6, 6, |
620 | 6, 6, 6, 6 |
621 | # endif /* !BUCKETS_ROOT2 */ |
622 | }; |
623 | # else /* !SMALL_BUCKET_VIA_TABLE */ |
624 | # define START_SHIFTS_BUCKET MIN_BUCKET |
625 | # define START_SHIFT (MIN_BUC_POW2 - 1) |
626 | # endif /* !SMALL_BUCKET_VIA_TABLE */ |
627 | #else /* !PACK_MALLOC */ |
628 | # define MEM_OVERHEAD(bucket) M_OVERHEAD |
629 | # ifdef SMALL_BUCKET_VIA_TABLE |
630 | # undef SMALL_BUCKET_VIA_TABLE |
631 | # endif |
632 | # define START_SHIFTS_BUCKET MIN_BUCKET |
633 | # define START_SHIFT (MIN_BUC_POW2 - 1) |
634 | #endif /* !PACK_MALLOC */ |
cf5c4ad8 |
635 | |
8d063cd8 |
636 | /* |
55497cff |
637 | * Big allocations are often of the size 2^n bytes. To make them a |
638 | * little bit better, make blocks of size 2^n+pagesize for big n. |
639 | */ |
640 | |
641 | #ifdef TWO_POT_OPTIMIZE |
642 | |
5f05dabc |
643 | # ifndef PERL_PAGESIZE |
644 | # define PERL_PAGESIZE 4096 |
645 | # endif |
e8bc2b5c |
646 | # ifndef FIRST_BIG_POW2 |
647 | # define FIRST_BIG_POW2 15 /* 32K, 16K is used too often. */ |
5f05dabc |
648 | # endif |
e8bc2b5c |
649 | # define FIRST_BIG_BLOCK (1<<FIRST_BIG_POW2) |
55497cff |
650 | /* If this value or more, check against bigger blocks. */ |
651 | # define FIRST_BIG_BOUND (FIRST_BIG_BLOCK - M_OVERHEAD) |
652 | /* If less than this value, goes into 2^n-overhead-block. */ |
653 | # define LAST_SMALL_BOUND ((FIRST_BIG_BLOCK>>1) - M_OVERHEAD) |
654 | |
e8bc2b5c |
655 | # define POW2_OPTIMIZE_ADJUST(nbytes) \ |
656 | ((nbytes >= FIRST_BIG_BOUND) ? nbytes -= PERL_PAGESIZE : 0) |
657 | # define POW2_OPTIMIZE_SURPLUS(bucket) \ |
658 | ((bucket >= FIRST_BIG_POW2 * BUCKETS_PER_POW2) ? PERL_PAGESIZE : 0) |
659 | |
660 | #else /* !TWO_POT_OPTIMIZE */ |
661 | # define POW2_OPTIMIZE_ADJUST(nbytes) |
662 | # define POW2_OPTIMIZE_SURPLUS(bucket) 0 |
663 | #endif /* !TWO_POT_OPTIMIZE */ |
664 | |
665 | #if defined(HAS_64K_LIMIT) && defined(PERL_CORE) |
666 | # define BARK_64K_LIMIT(what,nbytes,size) \ |
667 | if (nbytes > 0xffff) { \ |
668 | PerlIO_printf(PerlIO_stderr(), \ |
669 | "%s too large: %lx\n", what, size); \ |
670 | my_exit(1); \ |
671 | } |
672 | #else /* !HAS_64K_LIMIT || !PERL_CORE */ |
673 | # define BARK_64K_LIMIT(what,nbytes,size) |
674 | #endif /* !HAS_64K_LIMIT || !PERL_CORE */ |
55497cff |
675 | |
e8bc2b5c |
676 | #ifndef MIN_SBRK |
677 | # define MIN_SBRK 2048 |
678 | #endif |
679 | |
680 | #ifndef FIRST_SBRK |
d720c441 |
681 | # define FIRST_SBRK (48*1024) |
e8bc2b5c |
682 | #endif |
683 | |
684 | /* Minimal sbrk in percents of what is already alloced. */ |
685 | #ifndef MIN_SBRK_FRAC |
686 | # define MIN_SBRK_FRAC 3 |
687 | #endif |
688 | |
689 | #ifndef SBRK_ALLOW_FAILURES |
690 | # define SBRK_ALLOW_FAILURES 3 |
691 | #endif |
55497cff |
692 | |
e8bc2b5c |
693 | #ifndef SBRK_FAILURE_PRICE |
694 | # define SBRK_FAILURE_PRICE 50 |
55497cff |
695 | #endif |
696 | |
e8bc2b5c |
697 | #if defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE) |
698 | |
699 | # ifndef BIG_SIZE |
700 | # define BIG_SIZE (1<<16) /* 64K */ |
701 | # endif |
702 | |
3541dd58 |
703 | #ifdef I_MACH_CTHREADS |
772fe5b3 |
704 | # undef MUTEX_LOCK |
705 | # define MUTEX_LOCK(m) STMT_START { if (*m) mutex_lock(*m); } STMT_END |
706 | # undef MUTEX_UNLOCK |
707 | # define MUTEX_UNLOCK(m) STMT_START { if (*m) mutex_unlock(*m); } STMT_END |
3541dd58 |
708 | #endif |
709 | |
55497cff |
710 | static char *emergency_buffer; |
711 | static MEM_SIZE emergency_buffer_size; |
712 | |
864dbfa3 |
713 | STATIC Malloc_t |
714 | emergency_sbrk(pTHX_ MEM_SIZE size) |
55497cff |
715 | { |
28ac10b1 |
716 | MEM_SIZE rsize = (((size - 1)>>LOG_OF_MIN_ARENA) + 1)<<LOG_OF_MIN_ARENA; |
717 | |
55497cff |
718 | if (size >= BIG_SIZE) { |
719 | /* Give the possibility to recover: */ |
741df71a |
720 | MALLOC_UNLOCK; |
1b979e0a |
721 | croak("Out of memory during \"large\" request for %i bytes", size); |
55497cff |
722 | } |
723 | |
28ac10b1 |
724 | if (emergency_buffer_size >= rsize) { |
725 | char *old = emergency_buffer; |
726 | |
727 | emergency_buffer_size -= rsize; |
728 | emergency_buffer += rsize; |
729 | return old; |
730 | } else { |
18f739ee |
731 | dTHR; |
55497cff |
732 | /* First offense, give a possibility to recover by dieing. */ |
733 | /* No malloc involved here: */ |
4a33f861 |
734 | GV **gvp = (GV**)hv_fetch(PL_defstash, "^M", 2, 0); |
55497cff |
735 | SV *sv; |
736 | char *pv; |
28ac10b1 |
737 | int have = 0; |
2d8e6c8d |
738 | STRLEN n_a; |
55497cff |
739 | |
28ac10b1 |
740 | if (emergency_buffer_size) { |
741 | add_to_chain(emergency_buffer, emergency_buffer_size, 0); |
742 | emergency_buffer_size = 0; |
743 | emergency_buffer = Nullch; |
744 | have = 1; |
745 | } |
4a33f861 |
746 | if (!gvp) gvp = (GV**)hv_fetch(PL_defstash, "\015", 1, 0); |
55497cff |
747 | if (!gvp || !(sv = GvSV(*gvp)) || !SvPOK(sv) |
28ac10b1 |
748 | || (SvLEN(sv) < (1<<LOG_OF_MIN_ARENA) - M_OVERHEAD)) { |
749 | if (have) |
750 | goto do_croak; |
55497cff |
751 | return (char *)-1; /* Now die die die... */ |
28ac10b1 |
752 | } |
55497cff |
753 | /* Got it, now detach SvPV: */ |
2d8e6c8d |
754 | pv = SvPV(sv, n_a); |
55497cff |
755 | /* Check alignment: */ |
5bbd1ef5 |
756 | if (((UV)(pv - sizeof(union overhead))) & (NEEDED_ALIGNMENT - 1)) { |
55497cff |
757 | PerlIO_puts(PerlIO_stderr(),"Bad alignment of $^M!\n"); |
bbce6d69 |
758 | return (char *)-1; /* die die die */ |
55497cff |
759 | } |
760 | |
28ac10b1 |
761 | emergency_buffer = pv - sizeof(union overhead); |
762 | emergency_buffer_size = malloced_size(pv) + M_OVERHEAD; |
55497cff |
763 | SvPOK_off(sv); |
28ac10b1 |
764 | SvPVX(sv) = Nullch; |
765 | SvCUR(sv) = SvLEN(sv) = 0; |
55497cff |
766 | } |
28ac10b1 |
767 | do_croak: |
741df71a |
768 | MALLOC_UNLOCK; |
28ac10b1 |
769 | croak("Out of memory during request for %i bytes", size); |
55497cff |
770 | } |
771 | |
e8bc2b5c |
772 | #else /* !(defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)) */ |
55497cff |
773 | # define emergency_sbrk(size) -1 |
e8bc2b5c |
774 | #endif /* !(defined(PERL_EMERGENCY_SBRK) && defined(PERL_CORE)) */ |
55497cff |
775 | |
776 | /* |
e8bc2b5c |
777 | * nextf[i] is the pointer to the next free block of size 2^i. The |
8d063cd8 |
778 | * smallest allocatable block is 8 bytes. The overhead information |
779 | * precedes the data area returned to the user. |
780 | */ |
e8bc2b5c |
781 | #define NBUCKETS (32*BUCKETS_PER_POW2 + 1) |
8d063cd8 |
782 | static union overhead *nextf[NBUCKETS]; |
cf5c4ad8 |
783 | |
784 | #ifdef USE_PERL_SBRK |
785 | #define sbrk(a) Perl_sbrk(a) |
20ce7b12 |
786 | Malloc_t Perl_sbrk (int size); |
8ac85365 |
787 | #else |
788 | #ifdef DONT_DECLARE_STD |
789 | #ifdef I_UNISTD |
790 | #include <unistd.h> |
791 | #endif |
cf5c4ad8 |
792 | #else |
52082926 |
793 | extern Malloc_t sbrk(int); |
8ac85365 |
794 | #endif |
cf5c4ad8 |
795 | #endif |
8d063cd8 |
796 | |
c07a80fd |
797 | #ifdef DEBUGGING_MSTATS |
8d063cd8 |
798 | /* |
799 | * nmalloc[i] is the difference between the number of mallocs and frees |
800 | * for a given block size. |
801 | */ |
802 | static u_int nmalloc[NBUCKETS]; |
5f05dabc |
803 | static u_int sbrk_slack; |
804 | static u_int start_slack; |
8d063cd8 |
805 | #endif |
806 | |
e8bc2b5c |
807 | static u_int goodsbrk; |
808 | |
760ac839 |
809 | #ifdef DEBUGGING |
3541dd58 |
810 | #undef ASSERT |
811 | #define ASSERT(p,diag) if (!(p)) botch(diag,STRINGIFY(p)); else |
864dbfa3 |
812 | STATIC void |
813 | botch(pTHX_ char *diag, char *s) |
8d063cd8 |
814 | { |
d720c441 |
815 | PerlIO_printf(PerlIO_stderr(), "assertion botched (%s?): %s\n", diag, s); |
3028581b |
816 | PerlProc_abort(); |
8d063cd8 |
817 | } |
818 | #else |
3541dd58 |
819 | #define ASSERT(p, diag) |
8d063cd8 |
820 | #endif |
821 | |
2304df62 |
822 | Malloc_t |
86058a2d |
823 | Perl_malloc(register size_t nbytes) |
8d063cd8 |
824 | { |
825 | register union overhead *p; |
e8bc2b5c |
826 | register int bucket; |
ee0007ab |
827 | register MEM_SIZE shiftr; |
8d063cd8 |
828 | |
c2a5c2d2 |
829 | #if defined(DEBUGGING) || defined(RCHECK) |
ee0007ab |
830 | MEM_SIZE size = nbytes; |
45d8adaa |
831 | #endif |
832 | |
e8bc2b5c |
833 | BARK_64K_LIMIT("Allocation",nbytes,nbytes); |
45d8adaa |
834 | #ifdef DEBUGGING |
835 | if ((long)nbytes < 0) |
d720c441 |
836 | croak("%s", "panic: malloc"); |
45d8adaa |
837 | #endif |
45d8adaa |
838 | |
741df71a |
839 | MALLOC_LOCK; |
8d063cd8 |
840 | /* |
841 | * Convert amount of memory requested into |
842 | * closest block size stored in hash buckets |
843 | * which satisfies request. Account for |
844 | * space used per block for accounting. |
845 | */ |
cf5c4ad8 |
846 | #ifdef PACK_MALLOC |
e8bc2b5c |
847 | # ifdef SMALL_BUCKET_VIA_TABLE |
848 | if (nbytes == 0) |
849 | bucket = MIN_BUCKET; |
850 | else if (nbytes <= SIZE_TABLE_MAX) { |
851 | bucket = bucket_of[(nbytes - 1) >> BUCKET_TABLE_SHIFT]; |
852 | } else |
853 | # else |
043bf814 |
854 | if (nbytes == 0) |
855 | nbytes = 1; |
e8bc2b5c |
856 | if (nbytes <= MAX_POW2_ALGO) goto do_shifts; |
857 | else |
858 | # endif |
55497cff |
859 | #endif |
e8bc2b5c |
860 | { |
861 | POW2_OPTIMIZE_ADJUST(nbytes); |
862 | nbytes += M_OVERHEAD; |
863 | nbytes = (nbytes + 3) &~ 3; |
864 | do_shifts: |
865 | shiftr = (nbytes - 1) >> START_SHIFT; |
866 | bucket = START_SHIFTS_BUCKET; |
867 | /* apart from this loop, this is O(1) */ |
868 | while (shiftr >>= 1) |
869 | bucket += BUCKETS_PER_POW2; |
cf5c4ad8 |
870 | } |
8d063cd8 |
871 | /* |
872 | * If nothing in hash bucket right now, |
873 | * request more memory from the system. |
874 | */ |
875 | if (nextf[bucket] == NULL) |
876 | morecore(bucket); |
e8bc2b5c |
877 | if ((p = nextf[bucket]) == NULL) { |
741df71a |
878 | MALLOC_UNLOCK; |
55497cff |
879 | #ifdef PERL_CORE |
4a33f861 |
880 | if (!PL_nomemok) { |
760ac839 |
881 | PerlIO_puts(PerlIO_stderr(),"Out of memory!\n"); |
79072805 |
882 | my_exit(1); |
ee0007ab |
883 | } |
45d8adaa |
884 | #else |
8d063cd8 |
885 | return (NULL); |
45d8adaa |
886 | #endif |
887 | } |
888 | |
e8bc2b5c |
889 | DEBUG_m(PerlIO_printf(Perl_debug_log, |
890 | "0x%lx: (%05lu) malloc %ld bytes\n", |
4a33f861 |
891 | (unsigned long)(p+1), (unsigned long)(PL_an++), |
e8bc2b5c |
892 | (long)size)); |
45d8adaa |
893 | |
8d063cd8 |
894 | /* remove from linked list */ |
802004fa |
895 | #if defined(RCHECK) |
896 | if (((UV)p) & (MEM_ALIGNBYTES - 1)) |
760ac839 |
897 | PerlIO_printf(PerlIO_stderr(), "Corrupt malloc ptr 0x%lx at 0x%lx\n", |
a0d0e21e |
898 | (unsigned long)*((int*)p),(unsigned long)p); |
bf38876a |
899 | #endif |
900 | nextf[bucket] = p->ov_next; |
e8bc2b5c |
901 | #ifdef IGNORE_SMALL_BAD_FREE |
902 | if (bucket >= FIRST_BUCKET_WITH_CHECK) |
903 | #endif |
904 | OV_MAGIC(p, bucket) = MAGIC; |
cf5c4ad8 |
905 | #ifndef PACK_MALLOC |
906 | OV_INDEX(p) = bucket; |
907 | #endif |
8d063cd8 |
908 | #ifdef RCHECK |
909 | /* |
910 | * Record allocated size of block and |
911 | * bound space with magic numbers. |
912 | */ |
8d063cd8 |
913 | p->ov_rmagic = RMAGIC; |
e8bc2b5c |
914 | if (bucket <= MAX_SHORT_BUCKET) { |
915 | int i; |
916 | |
917 | nbytes = size + M_OVERHEAD; |
918 | p->ov_size = nbytes - 1; |
919 | if ((i = nbytes & 3)) { |
920 | i = 4 - i; |
921 | while (i--) |
922 | *((char *)((caddr_t)p + nbytes - RSLOP + i)) = RMAGIC_C; |
923 | } |
924 | nbytes = (nbytes + 3) &~ 3; |
925 | *((u_int *)((caddr_t)p + nbytes - RSLOP)) = RMAGIC; |
926 | } |
8d063cd8 |
927 | #endif |
741df71a |
928 | MALLOC_UNLOCK; |
cf5c4ad8 |
929 | return ((Malloc_t)(p + CHUNK_SHIFT)); |
8d063cd8 |
930 | } |
931 | |
e8bc2b5c |
932 | static char *last_sbrk_top; |
933 | static char *last_op; /* This arena can be easily extended. */ |
934 | static int sbrked_remains; |
935 | static int sbrk_good = SBRK_ALLOW_FAILURES * SBRK_FAILURE_PRICE; |
936 | |
937 | #ifdef DEBUGGING_MSTATS |
938 | static int sbrks; |
939 | #endif |
940 | |
941 | struct chunk_chain_s { |
942 | struct chunk_chain_s *next; |
943 | MEM_SIZE size; |
944 | }; |
945 | static struct chunk_chain_s *chunk_chain; |
946 | static int n_chunks; |
947 | static char max_bucket; |
948 | |
949 | /* Cutoff a piece of one of the chunks in the chain. Prefer smaller chunk. */ |
864dbfa3 |
950 | STATIC void * |
951 | get_from_chain(pTHX_ MEM_SIZE size) |
e8bc2b5c |
952 | { |
953 | struct chunk_chain_s *elt = chunk_chain, **oldp = &chunk_chain; |
954 | struct chunk_chain_s **oldgoodp = NULL; |
955 | long min_remain = LONG_MAX; |
956 | |
957 | while (elt) { |
958 | if (elt->size >= size) { |
959 | long remains = elt->size - size; |
960 | if (remains >= 0 && remains < min_remain) { |
961 | oldgoodp = oldp; |
962 | min_remain = remains; |
963 | } |
964 | if (remains == 0) { |
965 | break; |
966 | } |
967 | } |
968 | oldp = &( elt->next ); |
969 | elt = elt->next; |
970 | } |
971 | if (!oldgoodp) return NULL; |
972 | if (min_remain) { |
973 | void *ret = *oldgoodp; |
974 | struct chunk_chain_s *next = (*oldgoodp)->next; |
975 | |
976 | *oldgoodp = (struct chunk_chain_s *)((char*)ret + size); |
977 | (*oldgoodp)->size = min_remain; |
978 | (*oldgoodp)->next = next; |
979 | return ret; |
980 | } else { |
981 | void *ret = *oldgoodp; |
982 | *oldgoodp = (*oldgoodp)->next; |
983 | n_chunks--; |
984 | return ret; |
985 | } |
986 | } |
987 | |
864dbfa3 |
988 | STATIC void |
989 | add_to_chain(pTHX_ void *p, MEM_SIZE size, MEM_SIZE chip) |
e8bc2b5c |
990 | { |
991 | struct chunk_chain_s *next = chunk_chain; |
992 | char *cp = (char*)p; |
993 | |
994 | cp += chip; |
995 | chunk_chain = (struct chunk_chain_s *)cp; |
996 | chunk_chain->size = size - chip; |
997 | chunk_chain->next = next; |
998 | n_chunks++; |
999 | } |
1000 | |
864dbfa3 |
1001 | STATIC void * |
1002 | get_from_bigger_buckets(pTHX_ int bucket, MEM_SIZE size) |
e8bc2b5c |
1003 | { |
1004 | int price = 1; |
1005 | static int bucketprice[NBUCKETS]; |
1006 | while (bucket <= max_bucket) { |
1007 | /* We postpone stealing from bigger buckets until we want it |
1008 | often enough. */ |
1009 | if (nextf[bucket] && bucketprice[bucket]++ >= price) { |
1010 | /* Steal it! */ |
1011 | void *ret = (void*)(nextf[bucket] - 1 + CHUNK_SHIFT); |
1012 | bucketprice[bucket] = 0; |
1013 | if (((char*)nextf[bucket]) - M_OVERHEAD == last_op) { |
1014 | last_op = NULL; /* Disable optimization */ |
1015 | } |
1016 | nextf[bucket] = nextf[bucket]->ov_next; |
1017 | #ifdef DEBUGGING_MSTATS |
1018 | nmalloc[bucket]--; |
1019 | start_slack -= M_OVERHEAD; |
1020 | #endif |
1021 | add_to_chain(ret, (BUCKET_SIZE(bucket) + |
1022 | POW2_OPTIMIZE_SURPLUS(bucket)), |
1023 | size); |
1024 | return ret; |
1025 | } |
1026 | bucket++; |
1027 | } |
1028 | return NULL; |
1029 | } |
1030 | |
864dbfa3 |
1031 | STATIC union overhead * |
1032 | getpages(pTHX_ int needed, int *nblksp, int bucket) |
fa423c5b |
1033 | { |
1034 | /* Need to do (possibly expensive) system call. Try to |
1035 | optimize it for rare calling. */ |
1036 | MEM_SIZE require = needed - sbrked_remains; |
1037 | char *cp; |
1038 | union overhead *ovp; |
1039 | int slack = 0; |
1040 | |
1041 | if (sbrk_good > 0) { |
1042 | if (!last_sbrk_top && require < FIRST_SBRK) |
1043 | require = FIRST_SBRK; |
1044 | else if (require < MIN_SBRK) require = MIN_SBRK; |
1045 | |
1046 | if (require < goodsbrk * MIN_SBRK_FRAC / 100) |
1047 | require = goodsbrk * MIN_SBRK_FRAC / 100; |
1048 | require = ((require - 1 + MIN_SBRK) / MIN_SBRK) * MIN_SBRK; |
1049 | } else { |
1050 | require = needed; |
1051 | last_sbrk_top = 0; |
1052 | sbrked_remains = 0; |
1053 | } |
1054 | |
1055 | DEBUG_m(PerlIO_printf(Perl_debug_log, |
1056 | "sbrk(%ld) for %ld-byte-long arena\n", |
1057 | (long)require, (long) needed)); |
1058 | cp = (char *)sbrk(require); |
1059 | #ifdef DEBUGGING_MSTATS |
1060 | sbrks++; |
1061 | #endif |
1062 | if (cp == last_sbrk_top) { |
1063 | /* Common case, anything is fine. */ |
1064 | sbrk_good++; |
1065 | ovp = (union overhead *) (cp - sbrked_remains); |
e9397286 |
1066 | last_op = cp - sbrked_remains; |
fa423c5b |
1067 | sbrked_remains = require - (needed - sbrked_remains); |
1068 | } else if (cp == (char *)-1) { /* no more room! */ |
1069 | ovp = (union overhead *)emergency_sbrk(needed); |
1070 | if (ovp == (union overhead *)-1) |
1071 | return 0; |
e9397286 |
1072 | if (((char*)ovp) > last_op) { /* Cannot happen with current emergency_sbrk() */ |
1073 | last_op = 0; |
1074 | } |
fa423c5b |
1075 | return ovp; |
1076 | } else { /* Non-continuous or first sbrk(). */ |
1077 | long add = sbrked_remains; |
1078 | char *newcp; |
1079 | |
1080 | if (sbrked_remains) { /* Put rest into chain, we |
1081 | cannot use it right now. */ |
1082 | add_to_chain((void*)(last_sbrk_top - sbrked_remains), |
1083 | sbrked_remains, 0); |
1084 | } |
1085 | |
1086 | /* Second, check alignment. */ |
1087 | slack = 0; |
1088 | |
61ae2fbf |
1089 | #if !defined(atarist) && !defined(__MINT__) /* on the atari we dont have to worry about this */ |
fa423c5b |
1090 | # ifndef I286 /* The sbrk(0) call on the I286 always returns the next segment */ |
5bbd1ef5 |
1091 | /* WANTED_ALIGNMENT may be more than NEEDED_ALIGNMENT, but this may |
1092 | improve performance of memory access. */ |
1093 | if ((UV)cp & (WANTED_ALIGNMENT - 1)) { /* Not aligned. */ |
1094 | slack = WANTED_ALIGNMENT - ((UV)cp & (WANTED_ALIGNMENT - 1)); |
fa423c5b |
1095 | add += slack; |
1096 | } |
1097 | # endif |
61ae2fbf |
1098 | #endif /* !atarist && !MINT */ |
fa423c5b |
1099 | |
1100 | if (add) { |
1101 | DEBUG_m(PerlIO_printf(Perl_debug_log, |
1102 | "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", |
1103 | (long)add, (long) slack, |
1104 | (long) sbrked_remains)); |
1105 | newcp = (char *)sbrk(add); |
1106 | #if defined(DEBUGGING_MSTATS) |
1107 | sbrks++; |
1108 | sbrk_slack += add; |
1109 | #endif |
1110 | if (newcp != cp + require) { |
1111 | /* Too bad: even rounding sbrk() is not continuous.*/ |
1112 | DEBUG_m(PerlIO_printf(Perl_debug_log, |
1113 | "failed to fix bad sbrk()\n")); |
1114 | #ifdef PACK_MALLOC |
1115 | if (slack) { |
741df71a |
1116 | MALLOC_UNLOCK; |
5bbd1ef5 |
1117 | fatalcroak("panic: Off-page sbrk\n"); |
fa423c5b |
1118 | } |
1119 | #endif |
1120 | if (sbrked_remains) { |
1121 | /* Try again. */ |
1122 | #if defined(DEBUGGING_MSTATS) |
1123 | sbrk_slack += require; |
1124 | #endif |
1125 | require = needed; |
1126 | DEBUG_m(PerlIO_printf(Perl_debug_log, |
1127 | "straight sbrk(%ld)\n", |
1128 | (long)require)); |
1129 | cp = (char *)sbrk(require); |
1130 | #ifdef DEBUGGING_MSTATS |
1131 | sbrks++; |
1132 | #endif |
1133 | if (cp == (char *)-1) |
1134 | return 0; |
1135 | } |
1136 | sbrk_good = -1; /* Disable optimization! |
1137 | Continue with not-aligned... */ |
1138 | } else { |
1139 | cp += slack; |
1140 | require += sbrked_remains; |
1141 | } |
1142 | } |
1143 | |
1144 | if (last_sbrk_top) { |
1145 | sbrk_good -= SBRK_FAILURE_PRICE; |
1146 | } |
1147 | |
1148 | ovp = (union overhead *) cp; |
1149 | /* |
1150 | * Round up to minimum allocation size boundary |
1151 | * and deduct from block count to reflect. |
1152 | */ |
1153 | |
5bbd1ef5 |
1154 | # if NEEDED_ALIGNMENT > MEM_ALIGNBYTES |
1155 | if ((UV)ovp & (NEEDED_ALIGNMENT - 1)) |
1156 | fatalcroak("Misalignment of sbrk()\n"); |
1157 | else |
1158 | # endif |
fa423c5b |
1159 | #ifndef I286 /* Again, this should always be ok on an 80286 */ |
5bbd1ef5 |
1160 | if ((UV)ovp & (MEM_ALIGNBYTES - 1)) { |
fa423c5b |
1161 | DEBUG_m(PerlIO_printf(Perl_debug_log, |
1162 | "fixing sbrk(): %d bytes off machine alignement\n", |
5bbd1ef5 |
1163 | (int)((UV)ovp & (MEM_ALIGNBYTES - 1)))); |
1164 | ovp = (union overhead *)(((UV)ovp + MEM_ALIGNBYTES) & |
1165 | (MEM_ALIGNBYTES - 1)); |
fa423c5b |
1166 | (*nblksp)--; |
1167 | # if defined(DEBUGGING_MSTATS) |
1168 | /* This is only approx. if TWO_POT_OPTIMIZE: */ |
5bbd1ef5 |
1169 | sbrk_slack += (1 << (bucket >> BUCKET_POW2_SHIFT)); |
fa423c5b |
1170 | # endif |
1171 | } |
1172 | #endif |
5bbd1ef5 |
1173 | ; /* Finish `else' */ |
fa423c5b |
1174 | sbrked_remains = require - needed; |
e9397286 |
1175 | last_op = cp; |
fa423c5b |
1176 | } |
1177 | last_sbrk_top = cp + require; |
fa423c5b |
1178 | #ifdef DEBUGGING_MSTATS |
1179 | goodsbrk += require; |
1180 | #endif |
1181 | return ovp; |
1182 | } |
1183 | |
864dbfa3 |
1184 | STATIC int |
1185 | getpages_adjacent(pTHX_ int require) |
fa423c5b |
1186 | { |
1187 | if (require <= sbrked_remains) { |
1188 | sbrked_remains -= require; |
1189 | } else { |
1190 | char *cp; |
1191 | |
1192 | require -= sbrked_remains; |
1193 | /* We do not try to optimize sbrks here, we go for place. */ |
1194 | cp = (char*) sbrk(require); |
1195 | #ifdef DEBUGGING_MSTATS |
1196 | sbrks++; |
1197 | goodsbrk += require; |
1198 | #endif |
1199 | if (cp == last_sbrk_top) { |
1200 | sbrked_remains = 0; |
1201 | last_sbrk_top = cp + require; |
1202 | } else { |
28ac10b1 |
1203 | if (cp == (char*)-1) { /* Out of memory */ |
1204 | #ifdef DEBUGGING_MSTATS |
1205 | goodsbrk -= require; |
1206 | #endif |
1207 | return 0; |
1208 | } |
fa423c5b |
1209 | /* Report the failure: */ |
1210 | if (sbrked_remains) |
1211 | add_to_chain((void*)(last_sbrk_top - sbrked_remains), |
1212 | sbrked_remains, 0); |
1213 | add_to_chain((void*)cp, require, 0); |
1214 | sbrk_good -= SBRK_FAILURE_PRICE; |
1215 | sbrked_remains = 0; |
1216 | last_sbrk_top = 0; |
1217 | last_op = 0; |
1218 | return 0; |
1219 | } |
1220 | } |
1221 | |
1222 | return 1; |
1223 | } |
1224 | |
8d063cd8 |
1225 | /* |
1226 | * Allocate more memory to the indicated bucket. |
1227 | */ |
864dbfa3 |
1228 | STATIC void |
1229 | morecore(pTHX_ register int bucket) |
8d063cd8 |
1230 | { |
72aaf631 |
1231 | register union overhead *ovp; |
8d063cd8 |
1232 | register int rnu; /* 2^rnu bytes will be requested */ |
fa423c5b |
1233 | int nblks; /* become nblks blocks of the desired size */ |
bbce6d69 |
1234 | register MEM_SIZE siz, needed; |
8d063cd8 |
1235 | |
1236 | if (nextf[bucket]) |
1237 | return; |
e8bc2b5c |
1238 | if (bucket == sizeof(MEM_SIZE)*8*BUCKETS_PER_POW2) { |
741df71a |
1239 | MALLOC_UNLOCK; |
d720c441 |
1240 | croak("%s", "Out of memory during ridiculously large request"); |
55497cff |
1241 | } |
d720c441 |
1242 | if (bucket > max_bucket) |
e8bc2b5c |
1243 | max_bucket = bucket; |
d720c441 |
1244 | |
e8bc2b5c |
1245 | rnu = ( (bucket <= (LOG_OF_MIN_ARENA << BUCKET_POW2_SHIFT)) |
1246 | ? LOG_OF_MIN_ARENA |
1247 | : (bucket >> BUCKET_POW2_SHIFT) ); |
1248 | /* This may be overwritten later: */ |
1249 | nblks = 1 << (rnu - (bucket >> BUCKET_POW2_SHIFT)); /* how many blocks to get */ |
1250 | needed = ((MEM_SIZE)1 << rnu) + POW2_OPTIMIZE_SURPLUS(bucket); |
1251 | if (nextf[rnu << BUCKET_POW2_SHIFT]) { /* 2048b bucket. */ |
1252 | ovp = nextf[rnu << BUCKET_POW2_SHIFT] - 1 + CHUNK_SHIFT; |
1253 | nextf[rnu << BUCKET_POW2_SHIFT] |
1254 | = nextf[rnu << BUCKET_POW2_SHIFT]->ov_next; |
1255 | #ifdef DEBUGGING_MSTATS |
1256 | nmalloc[rnu << BUCKET_POW2_SHIFT]--; |
1257 | start_slack -= M_OVERHEAD; |
1258 | #endif |
1259 | DEBUG_m(PerlIO_printf(Perl_debug_log, |
1260 | "stealing %ld bytes from %ld arena\n", |
1261 | (long) needed, (long) rnu << BUCKET_POW2_SHIFT)); |
1262 | } else if (chunk_chain |
1263 | && (ovp = (union overhead*) get_from_chain(needed))) { |
1264 | DEBUG_m(PerlIO_printf(Perl_debug_log, |
1265 | "stealing %ld bytes from chain\n", |
1266 | (long) needed)); |
d720c441 |
1267 | } else if ( (ovp = (union overhead*) |
1268 | get_from_bigger_buckets((rnu << BUCKET_POW2_SHIFT) + 1, |
1269 | needed)) ) { |
e8bc2b5c |
1270 | DEBUG_m(PerlIO_printf(Perl_debug_log, |
1271 | "stealing %ld bytes from bigger buckets\n", |
1272 | (long) needed)); |
1273 | } else if (needed <= sbrked_remains) { |
1274 | ovp = (union overhead *)(last_sbrk_top - sbrked_remains); |
1275 | sbrked_remains -= needed; |
1276 | last_op = (char*)ovp; |
fa423c5b |
1277 | } else |
1278 | ovp = getpages(needed, &nblks, bucket); |
e8bc2b5c |
1279 | |
fa423c5b |
1280 | if (!ovp) |
1281 | return; |
e8bc2b5c |
1282 | |
8d063cd8 |
1283 | /* |
1284 | * Add new memory allocated to that on |
1285 | * free list for this hash bucket. |
1286 | */ |
e8bc2b5c |
1287 | siz = BUCKET_SIZE(bucket); |
cf5c4ad8 |
1288 | #ifdef PACK_MALLOC |
72aaf631 |
1289 | *(u_char*)ovp = bucket; /* Fill index. */ |
e8bc2b5c |
1290 | if (bucket <= MAX_PACKED) { |
1291 | ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket)); |
1292 | nblks = N_BLKS(bucket); |
cf5c4ad8 |
1293 | # ifdef DEBUGGING_MSTATS |
e8bc2b5c |
1294 | start_slack += BLK_SHIFT(bucket); |
cf5c4ad8 |
1295 | # endif |
e8bc2b5c |
1296 | } else if (bucket < LOG_OF_MIN_ARENA * BUCKETS_PER_POW2) { |
1297 | ovp = (union overhead *) ((char*)ovp + BLK_SHIFT(bucket)); |
cf5c4ad8 |
1298 | siz -= sizeof(union overhead); |
72aaf631 |
1299 | } else ovp++; /* One chunk per block. */ |
e8bc2b5c |
1300 | #endif /* PACK_MALLOC */ |
72aaf631 |
1301 | nextf[bucket] = ovp; |
5f05dabc |
1302 | #ifdef DEBUGGING_MSTATS |
1303 | nmalloc[bucket] += nblks; |
e8bc2b5c |
1304 | if (bucket > MAX_PACKED) { |
1305 | start_slack += M_OVERHEAD * nblks; |
1306 | } |
5f05dabc |
1307 | #endif |
8d063cd8 |
1308 | while (--nblks > 0) { |
72aaf631 |
1309 | ovp->ov_next = (union overhead *)((caddr_t)ovp + siz); |
1310 | ovp = (union overhead *)((caddr_t)ovp + siz); |
8d063cd8 |
1311 | } |
8595d6f1 |
1312 | /* Not all sbrks return zeroed memory.*/ |
72aaf631 |
1313 | ovp->ov_next = (union overhead *)NULL; |
cf5c4ad8 |
1314 | #ifdef PACK_MALLOC |
e8bc2b5c |
1315 | if (bucket == 7*BUCKETS_PER_POW2) { /* Special case, explanation is above. */ |
1316 | union overhead *n_op = nextf[7*BUCKETS_PER_POW2]->ov_next; |
1317 | nextf[7*BUCKETS_PER_POW2] = |
1318 | (union overhead *)((caddr_t)nextf[7*BUCKETS_PER_POW2] |
1319 | - sizeof(union overhead)); |
1320 | nextf[7*BUCKETS_PER_POW2]->ov_next = n_op; |
cf5c4ad8 |
1321 | } |
1322 | #endif /* !PACK_MALLOC */ |
8d063cd8 |
1323 | } |
1324 | |
94b6baf5 |
1325 | Free_t |
86058a2d |
1326 | Perl_mfree(void *mp) |
8d063cd8 |
1327 | { |
ee0007ab |
1328 | register MEM_SIZE size; |
72aaf631 |
1329 | register union overhead *ovp; |
352d5a3a |
1330 | char *cp = (char*)mp; |
cf5c4ad8 |
1331 | #ifdef PACK_MALLOC |
1332 | u_char bucket; |
1333 | #endif |
8d063cd8 |
1334 | |
e8bc2b5c |
1335 | DEBUG_m(PerlIO_printf(Perl_debug_log, |
1336 | "0x%lx: (%05lu) free\n", |
4a33f861 |
1337 | (unsigned long)cp, (unsigned long)(PL_an++))); |
45d8adaa |
1338 | |
cf5c4ad8 |
1339 | if (cp == NULL) |
1340 | return; |
72aaf631 |
1341 | ovp = (union overhead *)((caddr_t)cp |
e8bc2b5c |
1342 | - sizeof (union overhead) * CHUNK_SHIFT); |
cf5c4ad8 |
1343 | #ifdef PACK_MALLOC |
72aaf631 |
1344 | bucket = OV_INDEX(ovp); |
cf5c4ad8 |
1345 | #endif |
e8bc2b5c |
1346 | #ifdef IGNORE_SMALL_BAD_FREE |
1347 | if ((bucket >= FIRST_BUCKET_WITH_CHECK) |
1348 | && (OV_MAGIC(ovp, bucket) != MAGIC)) |
1349 | #else |
1350 | if (OV_MAGIC(ovp, bucket) != MAGIC) |
1351 | #endif |
1352 | { |
68dc0745 |
1353 | static int bad_free_warn = -1; |
cf5c4ad8 |
1354 | if (bad_free_warn == -1) { |
5fd9e9a4 |
1355 | char *pbf = PerlEnv_getenv("PERL_BADFREE"); |
cf5c4ad8 |
1356 | bad_free_warn = (pbf) ? atoi(pbf) : 1; |
1357 | } |
1358 | if (!bad_free_warn) |
1359 | return; |
8990e307 |
1360 | #ifdef RCHECK |
a687059c |
1361 | warn("%s free() ignored", |
72aaf631 |
1362 | ovp->ov_rmagic == RMAGIC - 1 ? "Duplicate" : "Bad"); |
8990e307 |
1363 | #else |
d720c441 |
1364 | warn("%s", "Bad free() ignored"); |
8990e307 |
1365 | #endif |
8d063cd8 |
1366 | return; /* sanity */ |
e8bc2b5c |
1367 | } |
741df71a |
1368 | MALLOC_LOCK; |
8d063cd8 |
1369 | #ifdef RCHECK |
3541dd58 |
1370 | ASSERT(ovp->ov_rmagic == RMAGIC, "chunk's head overwrite"); |
e8bc2b5c |
1371 | if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) { |
1372 | int i; |
1373 | MEM_SIZE nbytes = ovp->ov_size + 1; |
1374 | |
1375 | if ((i = nbytes & 3)) { |
1376 | i = 4 - i; |
1377 | while (i--) { |
3541dd58 |
1378 | ASSERT(*((char *)((caddr_t)ovp + nbytes - RSLOP + i)) |
d720c441 |
1379 | == RMAGIC_C, "chunk's tail overwrite"); |
e8bc2b5c |
1380 | } |
1381 | } |
1382 | nbytes = (nbytes + 3) &~ 3; |
3541dd58 |
1383 | ASSERT(*(u_int *)((caddr_t)ovp + nbytes - RSLOP) == RMAGIC, "chunk's tail overwrite"); |
e8bc2b5c |
1384 | } |
72aaf631 |
1385 | ovp->ov_rmagic = RMAGIC - 1; |
8d063cd8 |
1386 | #endif |
3541dd58 |
1387 | ASSERT(OV_INDEX(ovp) < NBUCKETS, "chunk's head overwrite"); |
72aaf631 |
1388 | size = OV_INDEX(ovp); |
1389 | ovp->ov_next = nextf[size]; |
1390 | nextf[size] = ovp; |
741df71a |
1391 | MALLOC_UNLOCK; |
8d063cd8 |
1392 | } |
1393 | |
1394 | /* |
1395 | * When a program attempts "storage compaction" as mentioned in the |
1396 | * old malloc man page, it realloc's an already freed block. Usually |
1397 | * this is the last block it freed; occasionally it might be farther |
1398 | * back. We have to search all the free lists for the block in order |
1399 | * to determine its bucket: 1st we make one pass thru the lists |
1400 | * checking only the first block in each; if that fails we search |
378cc40b |
1401 | * ``reall_srchlen'' blocks in each list for a match (the variable |
8d063cd8 |
1402 | * is extern so the caller can modify it). If that fails we just copy |
1403 | * however many bytes was given to realloc() and hope it's not huge. |
1404 | */ |
22c35a8c |
1405 | #define reall_srchlen 4 /* 4 should be plenty, -1 =>'s whole list */ |
8d063cd8 |
1406 | |
2304df62 |
1407 | Malloc_t |
86058a2d |
1408 | Perl_realloc(void *mp, size_t nbytes) |
8d063cd8 |
1409 | { |
ee0007ab |
1410 | register MEM_SIZE onb; |
72aaf631 |
1411 | union overhead *ovp; |
d720c441 |
1412 | char *res; |
1413 | int prev_bucket; |
e8bc2b5c |
1414 | register int bucket; |
1415 | int was_alloced = 0, incr; |
352d5a3a |
1416 | char *cp = (char*)mp; |
8d063cd8 |
1417 | |
e8bc2b5c |
1418 | #if defined(DEBUGGING) || !defined(PERL_CORE) |
ee0007ab |
1419 | MEM_SIZE size = nbytes; |
45d8adaa |
1420 | |
45d8adaa |
1421 | if ((long)nbytes < 0) |
d720c441 |
1422 | croak("%s", "panic: realloc"); |
45d8adaa |
1423 | #endif |
e8bc2b5c |
1424 | |
1425 | BARK_64K_LIMIT("Reallocation",nbytes,size); |
1426 | if (!cp) |
86058a2d |
1427 | return Perl_malloc(nbytes); |
45d8adaa |
1428 | |
741df71a |
1429 | MALLOC_LOCK; |
72aaf631 |
1430 | ovp = (union overhead *)((caddr_t)cp |
e8bc2b5c |
1431 | - sizeof (union overhead) * CHUNK_SHIFT); |
1432 | bucket = OV_INDEX(ovp); |
1433 | #ifdef IGNORE_SMALL_BAD_FREE |
1434 | if ((bucket < FIRST_BUCKET_WITH_CHECK) |
1435 | || (OV_MAGIC(ovp, bucket) == MAGIC)) |
1436 | #else |
1437 | if (OV_MAGIC(ovp, bucket) == MAGIC) |
1438 | #endif |
1439 | { |
55497cff |
1440 | was_alloced = 1; |
8d063cd8 |
1441 | } else { |
1442 | /* |
1443 | * Already free, doing "compaction". |
1444 | * |
1445 | * Search for the old block of memory on the |
1446 | * free list. First, check the most common |
1447 | * case (last element free'd), then (this failing) |
378cc40b |
1448 | * the last ``reall_srchlen'' items free'd. |
8d063cd8 |
1449 | * If all lookups fail, then assume the size of |
1450 | * the memory block being realloc'd is the |
1451 | * smallest possible. |
1452 | */ |
e8bc2b5c |
1453 | if ((bucket = findbucket(ovp, 1)) < 0 && |
1454 | (bucket = findbucket(ovp, reall_srchlen)) < 0) |
1455 | bucket = 0; |
8d063cd8 |
1456 | } |
e8bc2b5c |
1457 | onb = BUCKET_SIZE_REAL(bucket); |
55497cff |
1458 | /* |
1459 | * avoid the copy if same size block. |
e8bc2b5c |
1460 | * We are not agressive with boundary cases. Note that it might |
1461 | * (for a small number of cases) give false negative if |
55497cff |
1462 | * both new size and old one are in the bucket for |
e8bc2b5c |
1463 | * FIRST_BIG_POW2, but the new one is near the lower end. |
1464 | * |
1465 | * We do not try to go to 1.5 times smaller bucket so far. |
55497cff |
1466 | */ |
e8bc2b5c |
1467 | if (nbytes > onb) incr = 1; |
1468 | else { |
1469 | #ifdef DO_NOT_TRY_HARDER_WHEN_SHRINKING |
1470 | if ( /* This is a little bit pessimal if PACK_MALLOC: */ |
1471 | nbytes > ( (onb >> 1) - M_OVERHEAD ) |
1472 | # ifdef TWO_POT_OPTIMIZE |
1473 | || (bucket == FIRST_BIG_POW2 && nbytes >= LAST_SMALL_BOUND ) |
1474 | # endif |
1475 | ) |
1476 | #else /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */ |
1477 | prev_bucket = ( (bucket > MAX_PACKED + 1) |
1478 | ? bucket - BUCKETS_PER_POW2 |
1479 | : bucket - 1); |
1480 | if (nbytes > BUCKET_SIZE_REAL(prev_bucket)) |
1481 | #endif /* !DO_NOT_TRY_HARDER_WHEN_SHRINKING */ |
1482 | incr = 0; |
1483 | else incr = -1; |
1484 | } |
1485 | if (!was_alloced |
2ce36478 |
1486 | #ifdef STRESS_REALLOC |
e8bc2b5c |
1487 | || 1 /* always do it the hard way */ |
2ce36478 |
1488 | #endif |
e8bc2b5c |
1489 | ) goto hard_way; |
1490 | else if (incr == 0) { |
852c2e52 |
1491 | inplace_label: |
a687059c |
1492 | #ifdef RCHECK |
1493 | /* |
1494 | * Record new allocated size of block and |
1495 | * bound space with magic numbers. |
1496 | */ |
72aaf631 |
1497 | if (OV_INDEX(ovp) <= MAX_SHORT_BUCKET) { |
e8bc2b5c |
1498 | int i, nb = ovp->ov_size + 1; |
1499 | |
1500 | if ((i = nb & 3)) { |
1501 | i = 4 - i; |
1502 | while (i--) { |
3541dd58 |
1503 | ASSERT(*((char *)((caddr_t)ovp + nb - RSLOP + i)) == RMAGIC_C, "chunk's tail overwrite"); |
e8bc2b5c |
1504 | } |
1505 | } |
1506 | nb = (nb + 3) &~ 3; |
3541dd58 |
1507 | ASSERT(*(u_int *)((caddr_t)ovp + nb - RSLOP) == RMAGIC, "chunk's tail overwrite"); |
a687059c |
1508 | /* |
1509 | * Convert amount of memory requested into |
1510 | * closest block size stored in hash buckets |
1511 | * which satisfies request. Account for |
1512 | * space used per block for accounting. |
1513 | */ |
cf5c4ad8 |
1514 | nbytes += M_OVERHEAD; |
72aaf631 |
1515 | ovp->ov_size = nbytes - 1; |
e8bc2b5c |
1516 | if ((i = nbytes & 3)) { |
1517 | i = 4 - i; |
1518 | while (i--) |
1519 | *((char *)((caddr_t)ovp + nbytes - RSLOP + i)) |
1520 | = RMAGIC_C; |
1521 | } |
1522 | nbytes = (nbytes + 3) &~ 3; |
72aaf631 |
1523 | *((u_int *)((caddr_t)ovp + nbytes - RSLOP)) = RMAGIC; |
a687059c |
1524 | } |
1525 | #endif |
45d8adaa |
1526 | res = cp; |
741df71a |
1527 | MALLOC_UNLOCK; |
42ac124e |
1528 | DEBUG_m(PerlIO_printf(Perl_debug_log, |
1529 | "0x%lx: (%05lu) realloc %ld bytes inplace\n", |
1530 | (unsigned long)res,(unsigned long)(PL_an++), |
1531 | (long)size)); |
e8bc2b5c |
1532 | } else if (incr == 1 && (cp - M_OVERHEAD == last_op) |
1533 | && (onb > (1 << LOG_OF_MIN_ARENA))) { |
1534 | MEM_SIZE require, newarena = nbytes, pow; |
1535 | int shiftr; |
1536 | |
1537 | POW2_OPTIMIZE_ADJUST(newarena); |
1538 | newarena = newarena + M_OVERHEAD; |
1539 | /* newarena = (newarena + 3) &~ 3; */ |
1540 | shiftr = (newarena - 1) >> LOG_OF_MIN_ARENA; |
1541 | pow = LOG_OF_MIN_ARENA + 1; |
1542 | /* apart from this loop, this is O(1) */ |
1543 | while (shiftr >>= 1) |
1544 | pow++; |
1545 | newarena = (1 << pow) + POW2_OPTIMIZE_SURPLUS(pow * BUCKETS_PER_POW2); |
1546 | require = newarena - onb - M_OVERHEAD; |
1547 | |
fa423c5b |
1548 | if (getpages_adjacent(require)) { |
e8bc2b5c |
1549 | #ifdef DEBUGGING_MSTATS |
fa423c5b |
1550 | nmalloc[bucket]--; |
1551 | nmalloc[pow * BUCKETS_PER_POW2]++; |
e8bc2b5c |
1552 | #endif |
fa423c5b |
1553 | *(cp - M_OVERHEAD) = pow * BUCKETS_PER_POW2; /* Fill index. */ |
1554 | goto inplace_label; |
1555 | } else |
1556 | goto hard_way; |
e8bc2b5c |
1557 | } else { |
1558 | hard_way: |
741df71a |
1559 | MALLOC_UNLOCK; |
42ac124e |
1560 | DEBUG_m(PerlIO_printf(Perl_debug_log, |
1561 | "0x%lx: (%05lu) realloc %ld bytes the hard way\n", |
1562 | (unsigned long)cp,(unsigned long)(PL_an++), |
1563 | (long)size)); |
86058a2d |
1564 | if ((res = (char*)Perl_malloc(nbytes)) == NULL) |
e8bc2b5c |
1565 | return (NULL); |
1566 | if (cp != res) /* common optimization */ |
1567 | Copy(cp, res, (MEM_SIZE)(nbytes<onb?nbytes:onb), char); |
1568 | if (was_alloced) |
86058a2d |
1569 | Perl_mfree(cp); |
45d8adaa |
1570 | } |
2304df62 |
1571 | return ((Malloc_t)res); |
8d063cd8 |
1572 | } |
1573 | |
1574 | /* |
1575 | * Search ``srchlen'' elements of each free list for a block whose |
1576 | * header starts at ``freep''. If srchlen is -1 search the whole list. |
1577 | * Return bucket number, or -1 if not found. |
1578 | */ |
ee0007ab |
1579 | static int |
8ac85365 |
1580 | findbucket(union overhead *freep, int srchlen) |
8d063cd8 |
1581 | { |
1582 | register union overhead *p; |
1583 | register int i, j; |
1584 | |
1585 | for (i = 0; i < NBUCKETS; i++) { |
1586 | j = 0; |
1587 | for (p = nextf[i]; p && j != srchlen; p = p->ov_next) { |
1588 | if (p == freep) |
1589 | return (i); |
1590 | j++; |
1591 | } |
1592 | } |
1593 | return (-1); |
1594 | } |
1595 | |
cf5c4ad8 |
1596 | Malloc_t |
86058a2d |
1597 | Perl_calloc(register size_t elements, register size_t size) |
cf5c4ad8 |
1598 | { |
1599 | long sz = elements * size; |
86058a2d |
1600 | Malloc_t p = Perl_malloc(sz); |
cf5c4ad8 |
1601 | |
1602 | if (p) { |
1603 | memset((void*)p, 0, sz); |
1604 | } |
1605 | return p; |
1606 | } |
1607 | |
e8bc2b5c |
1608 | MEM_SIZE |
864dbfa3 |
1609 | Perl_malloced_size(pTHX_ void *p) |
e8bc2b5c |
1610 | { |
8d6dde3e |
1611 | union overhead *ovp = (union overhead *) |
1612 | ((caddr_t)p - sizeof (union overhead) * CHUNK_SHIFT); |
1613 | int bucket = OV_INDEX(ovp); |
1614 | #ifdef RCHECK |
1615 | /* The caller wants to have a complete control over the chunk, |
1616 | disable the memory checking inside the chunk. */ |
1617 | if (bucket <= MAX_SHORT_BUCKET) { |
1618 | MEM_SIZE size = BUCKET_SIZE_REAL(bucket); |
1619 | ovp->ov_size = size + M_OVERHEAD - 1; |
1620 | *((u_int *)((caddr_t)ovp + size + M_OVERHEAD - RSLOP)) = RMAGIC; |
1621 | } |
1622 | #endif |
e8bc2b5c |
1623 | return BUCKET_SIZE_REAL(bucket); |
1624 | } |
1625 | |
e8bc2b5c |
1626 | # ifdef BUCKETS_ROOT2 |
1627 | # define MIN_EVEN_REPORT 6 |
1628 | # else |
1629 | # define MIN_EVEN_REPORT MIN_BUCKET |
1630 | # endif |
8d063cd8 |
1631 | /* |
1632 | * mstats - print out statistics about malloc |
1633 | * |
1634 | * Prints two lines of numbers, one showing the length of the free list |
1635 | * for each size category, the second showing the number of mallocs - |
1636 | * frees for each size category. |
1637 | */ |
ee0007ab |
1638 | void |
864dbfa3 |
1639 | Perl_dump_mstats(pTHX_ char *s) |
8d063cd8 |
1640 | { |
df31f264 |
1641 | #ifdef DEBUGGING_MSTATS |
8d063cd8 |
1642 | register int i, j; |
1643 | register union overhead *p; |
e8bc2b5c |
1644 | int topbucket=0, topbucket_ev=0, topbucket_odd=0, totfree=0, total=0; |
c07a80fd |
1645 | u_int nfree[NBUCKETS]; |
e8bc2b5c |
1646 | int total_chain = 0; |
1647 | struct chunk_chain_s* nextchain = chunk_chain; |
8d063cd8 |
1648 | |
e8bc2b5c |
1649 | for (i = MIN_BUCKET ; i < NBUCKETS; i++) { |
8d063cd8 |
1650 | for (j = 0, p = nextf[i]; p; p = p->ov_next, j++) |
1651 | ; |
c07a80fd |
1652 | nfree[i] = j; |
e8bc2b5c |
1653 | totfree += nfree[i] * BUCKET_SIZE_REAL(i); |
1654 | total += nmalloc[i] * BUCKET_SIZE_REAL(i); |
1655 | if (nmalloc[i]) { |
1656 | i % 2 ? (topbucket_odd = i) : (topbucket_ev = i); |
1657 | topbucket = i; |
1658 | } |
c07a80fd |
1659 | } |
1660 | if (s) |
e8bc2b5c |
1661 | PerlIO_printf(PerlIO_stderr(), |
d720c441 |
1662 | "Memory allocation statistics %s (buckets %ld(%ld)..%ld(%ld)\n", |
e8bc2b5c |
1663 | s, |
d720c441 |
1664 | (long)BUCKET_SIZE_REAL(MIN_BUCKET), |
1665 | (long)BUCKET_SIZE(MIN_BUCKET), |
1666 | (long)BUCKET_SIZE_REAL(topbucket), (long)BUCKET_SIZE(topbucket)); |
5f05dabc |
1667 | PerlIO_printf(PerlIO_stderr(), "%8d free:", totfree); |
e8bc2b5c |
1668 | for (i = MIN_EVEN_REPORT; i <= topbucket; i += BUCKETS_PER_POW2) { |
1669 | PerlIO_printf(PerlIO_stderr(), |
1670 | ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2) |
1671 | ? " %5d" |
1672 | : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")), |
1673 | nfree[i]); |
1674 | } |
1675 | #ifdef BUCKETS_ROOT2 |
1676 | PerlIO_printf(PerlIO_stderr(), "\n\t "); |
1677 | for (i = MIN_BUCKET + 1; i <= topbucket_odd; i += BUCKETS_PER_POW2) { |
1678 | PerlIO_printf(PerlIO_stderr(), |
1679 | ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2) |
1680 | ? " %5d" |
1681 | : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")), |
1682 | nfree[i]); |
8d063cd8 |
1683 | } |
e8bc2b5c |
1684 | #endif |
5f05dabc |
1685 | PerlIO_printf(PerlIO_stderr(), "\n%8d used:", total - totfree); |
e8bc2b5c |
1686 | for (i = MIN_EVEN_REPORT; i <= topbucket; i += BUCKETS_PER_POW2) { |
1687 | PerlIO_printf(PerlIO_stderr(), |
1688 | ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2) |
1689 | ? " %5d" |
1690 | : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")), |
1691 | nmalloc[i] - nfree[i]); |
c07a80fd |
1692 | } |
e8bc2b5c |
1693 | #ifdef BUCKETS_ROOT2 |
1694 | PerlIO_printf(PerlIO_stderr(), "\n\t "); |
1695 | for (i = MIN_BUCKET + 1; i <= topbucket_odd; i += BUCKETS_PER_POW2) { |
1696 | PerlIO_printf(PerlIO_stderr(), |
1697 | ((i < 8*BUCKETS_PER_POW2 || i == 10*BUCKETS_PER_POW2) |
1698 | ? " %5d" |
1699 | : ((i < 12*BUCKETS_PER_POW2) ? " %3d" : " %d")), |
1700 | nmalloc[i] - nfree[i]); |
1701 | } |
1702 | #endif |
1703 | while (nextchain) { |
1704 | total_chain += nextchain->size; |
1705 | nextchain = nextchain->next; |
1706 | } |
1707 | PerlIO_printf(PerlIO_stderr(), "\nTotal sbrk(): %d/%d:%d. Odd ends: pad+heads+chain+tail: %d+%d+%d+%d.\n", |
1708 | goodsbrk + sbrk_slack, sbrks, sbrk_good, sbrk_slack, |
1709 | start_slack, total_chain, sbrked_remains); |
df31f264 |
1710 | #endif /* DEBUGGING_MSTATS */ |
c07a80fd |
1711 | } |
a687059c |
1712 | #endif /* lint */ |
cf5c4ad8 |
1713 | |
cf5c4ad8 |
1714 | #ifdef USE_PERL_SBRK |
1715 | |
8f1f23e8 |
1716 | # if defined(__MACHTEN_PPC__) || defined(NeXT) || defined(__NeXT__) |
38ac2dc8 |
1717 | # define PERL_SBRK_VIA_MALLOC |
1718 | /* |
1719 | * MachTen's malloc() returns a buffer aligned on a two-byte boundary. |
1720 | * While this is adequate, it may slow down access to longer data |
1721 | * types by forcing multiple memory accesses. It also causes |
1722 | * complaints when RCHECK is in force. So we allocate six bytes |
1723 | * more than we need to, and return an address rounded up to an |
1724 | * eight-byte boundary. |
1725 | * |
1726 | * 980701 Dominic Dunlop <domo@computer.org> |
1727 | */ |
5bbd1ef5 |
1728 | # define SYSTEM_ALLOC_ALIGNMENT 2 |
38ac2dc8 |
1729 | # endif |
1730 | |
760ac839 |
1731 | # ifdef PERL_SBRK_VIA_MALLOC |
cf5c4ad8 |
1732 | |
1733 | /* it may seem schizophrenic to use perl's malloc and let it call system */ |
1734 | /* malloc, the reason for that is only the 3.2 version of the OS that had */ |
1735 | /* frequent core dumps within nxzonefreenolock. This sbrk routine put an */ |
1736 | /* end to the cores */ |
1737 | |
38ac2dc8 |
1738 | # ifndef SYSTEM_ALLOC |
1739 | # define SYSTEM_ALLOC(a) malloc(a) |
1740 | # endif |
5bbd1ef5 |
1741 | # ifndef SYSTEM_ALLOC_ALIGNMENT |
1742 | # define SYSTEM_ALLOC_ALIGNMENT MEM_ALIGNBYTES |
1743 | # endif |
cf5c4ad8 |
1744 | |
760ac839 |
1745 | # endif /* PERL_SBRK_VIA_MALLOC */ |
cf5c4ad8 |
1746 | |
1747 | static IV Perl_sbrk_oldchunk; |
1748 | static long Perl_sbrk_oldsize; |
1749 | |
760ac839 |
1750 | # define PERLSBRK_32_K (1<<15) |
1751 | # define PERLSBRK_64_K (1<<16) |
cf5c4ad8 |
1752 | |
b63effbb |
1753 | Malloc_t |
df0003d4 |
1754 | Perl_sbrk(int size) |
cf5c4ad8 |
1755 | { |
1756 | IV got; |
1757 | int small, reqsize; |
1758 | |
1759 | if (!size) return 0; |
55497cff |
1760 | #ifdef PERL_CORE |
cf5c4ad8 |
1761 | reqsize = size; /* just for the DEBUG_m statement */ |
1762 | #endif |
57569e04 |
1763 | #ifdef PACK_MALLOC |
1764 | size = (size + 0x7ff) & ~0x7ff; |
1765 | #endif |
cf5c4ad8 |
1766 | if (size <= Perl_sbrk_oldsize) { |
1767 | got = Perl_sbrk_oldchunk; |
1768 | Perl_sbrk_oldchunk += size; |
1769 | Perl_sbrk_oldsize -= size; |
1770 | } else { |
1771 | if (size >= PERLSBRK_32_K) { |
1772 | small = 0; |
1773 | } else { |
cf5c4ad8 |
1774 | size = PERLSBRK_64_K; |
1775 | small = 1; |
1776 | } |
5bbd1ef5 |
1777 | # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT |
1778 | size += NEEDED_ALIGNMENT - SYSTEM_ALLOC_ALIGNMENT; |
1779 | # endif |
cf5c4ad8 |
1780 | got = (IV)SYSTEM_ALLOC(size); |
5bbd1ef5 |
1781 | # if NEEDED_ALIGNMENT > SYSTEM_ALLOC_ALIGNMENT |
5a7d6335 |
1782 | got = (got + NEEDED_ALIGNMENT - 1) & ~(NEEDED_ALIGNMENT - 1); |
5bbd1ef5 |
1783 | # endif |
cf5c4ad8 |
1784 | if (small) { |
1785 | /* Chunk is small, register the rest for future allocs. */ |
1786 | Perl_sbrk_oldchunk = got + reqsize; |
1787 | Perl_sbrk_oldsize = size - reqsize; |
1788 | } |
1789 | } |
1790 | |
fb73857a |
1791 | DEBUG_m(PerlIO_printf(Perl_debug_log, "sbrk malloc size %ld (reqsize %ld), left size %ld, give addr 0x%lx\n", |
cf5c4ad8 |
1792 | size, reqsize, Perl_sbrk_oldsize, got)); |
cf5c4ad8 |
1793 | |
1794 | return (void *)got; |
1795 | } |
1796 | |
1797 | #endif /* ! defined USE_PERL_SBRK */ |