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fa8d436c | 1 | /* Malloc implementation for multiple threads without lock contention. |
04277e02 | 2 | Copyright (C) 2001-2019 Free Software Foundation, Inc. |
fa8d436c UD |
3 | This file is part of the GNU C Library. |
4 | Contributed by Wolfram Gloger <wg@malloc.de>, 2001. | |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
cc7375ce RM |
7 | modify it under the terms of the GNU Lesser General Public License as |
8 | published by the Free Software Foundation; either version 2.1 of the | |
fa8d436c UD |
9 | License, or (at your option) any later version. |
10 | ||
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
cc7375ce | 14 | Lesser General Public License for more details. |
fa8d436c | 15 | |
cc7375ce | 16 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 | 17 | License along with the GNU C Library; see the file COPYING.LIB. If |
5a82c748 | 18 | not, see <https://www.gnu.org/licenses/>. */ |
fa8d436c | 19 | |
a28b6b0a RM |
20 | #include <stdbool.h> |
21 | ||
67e58f39 SP |
22 | #if HAVE_TUNABLES |
23 | # define TUNABLE_NAMESPACE malloc | |
24 | #endif | |
25 | #include <elf/dl-tunables.h> | |
26 | ||
fa8d436c UD |
27 | /* Compile-time constants. */ |
28 | ||
6c8dbf00 | 29 | #define HEAP_MIN_SIZE (32 * 1024) |
fa8d436c | 30 | #ifndef HEAP_MAX_SIZE |
e404fb16 | 31 | # ifdef DEFAULT_MMAP_THRESHOLD_MAX |
bd2c2341 | 32 | # define HEAP_MAX_SIZE (2 * DEFAULT_MMAP_THRESHOLD_MAX) |
e404fb16 | 33 | # else |
6c8dbf00 | 34 | # define HEAP_MAX_SIZE (1024 * 1024) /* must be a power of two */ |
e404fb16 | 35 | # endif |
fa8d436c UD |
36 | #endif |
37 | ||
38 | /* HEAP_MIN_SIZE and HEAP_MAX_SIZE limit the size of mmap()ed heaps | |
39 | that are dynamically created for multi-threaded programs. The | |
40 | maximum size must be a power of two, for fast determination of | |
41 | which heap belongs to a chunk. It should be much larger than the | |
42 | mmap threshold, so that requests with a size just below that | |
43 | threshold can be fulfilled without creating too many heaps. */ | |
44 | ||
fa8d436c UD |
45 | /***************************************************************************/ |
46 | ||
47 | #define top(ar_ptr) ((ar_ptr)->top) | |
48 | ||
49 | /* A heap is a single contiguous memory region holding (coalesceable) | |
50 | malloc_chunks. It is allocated with mmap() and always starts at an | |
22a89187 | 51 | address aligned to HEAP_MAX_SIZE. */ |
fa8d436c | 52 | |
6c8dbf00 OB |
53 | typedef struct _heap_info |
54 | { | |
fa8d436c UD |
55 | mstate ar_ptr; /* Arena for this heap. */ |
56 | struct _heap_info *prev; /* Previous heap. */ | |
57 | size_t size; /* Current size in bytes. */ | |
6c8dbf00 OB |
58 | size_t mprotect_size; /* Size in bytes that has been mprotected |
59 | PROT_READ|PROT_WRITE. */ | |
7d013a64 RM |
60 | /* Make sure the following data is properly aligned, particularly |
61 | that sizeof (heap_info) + 2 * SIZE_SZ is a multiple of | |
c7fd3362 JJ |
62 | MALLOC_ALIGNMENT. */ |
63 | char pad[-6 * SIZE_SZ & MALLOC_ALIGN_MASK]; | |
fa8d436c UD |
64 | } heap_info; |
65 | ||
7d013a64 RM |
66 | /* Get a compile-time error if the heap_info padding is not correct |
67 | to make alignment work as expected in sYSMALLOc. */ | |
68 | extern int sanity_check_heap_info_alignment[(sizeof (heap_info) | |
6c8dbf00 OB |
69 | + 2 * SIZE_SZ) % MALLOC_ALIGNMENT |
70 | ? -1 : 1]; | |
7d013a64 | 71 | |
6782806d FW |
72 | /* Thread specific data. */ |
73 | ||
74 | static __thread mstate thread_arena attribute_tls_model_ie; | |
75 | ||
90c400bd FW |
76 | /* Arena free list. free_list_lock synchronizes access to the |
77 | free_list variable below, and the next_free and attached_threads | |
78 | members of struct malloc_state objects. No other locks must be | |
79 | acquired after free_list_lock has been acquired. */ | |
fa8d436c | 80 | |
cbb47fa1 | 81 | __libc_lock_define_initialized (static, free_list_lock); |
02d46fc4 | 82 | static size_t narenas = 1; |
425ce2ed | 83 | static mstate free_list; |
fa8d436c | 84 | |
90c400bd FW |
85 | /* list_lock prevents concurrent writes to the next member of struct |
86 | malloc_state objects. | |
87 | ||
88 | Read access to the next member is supposed to synchronize with the | |
89 | atomic_write_barrier and the write to the next member in | |
90 | _int_new_arena. This suffers from data races; see the FIXME | |
91 | comments in _int_new_arena and reused_arena. | |
92 | ||
7962541a FW |
93 | list_lock also prevents concurrent forks. At the time list_lock is |
94 | acquired, no arena lock must have been acquired, but it is | |
95 | permitted to acquire arena locks subsequently, while list_lock is | |
96 | acquired. */ | |
cbb47fa1 | 97 | __libc_lock_define_initialized (static, list_lock); |
90c400bd | 98 | |
2a652f5a RM |
99 | /* Already initialized? */ |
100 | int __malloc_initialized = -1; | |
101 | ||
fa8d436c UD |
102 | /**************************************************************************/ |
103 | ||
fa8d436c UD |
104 | |
105 | /* arena_get() acquires an arena and locks the corresponding mutex. | |
106 | First, try the one last locked successfully by this thread. (This | |
107 | is the common case and handled with a macro for speed.) Then, loop | |
108 | once over the circularly linked list of arenas. If no arena is | |
109 | readily available, create a new one. In this latter case, `size' | |
110 | is just a hint as to how much memory will be required immediately | |
111 | in the new arena. */ | |
112 | ||
113 | #define arena_get(ptr, size) do { \ | |
6782806d | 114 | ptr = thread_arena; \ |
6c8dbf00 OB |
115 | arena_lock (ptr, size); \ |
116 | } while (0) | |
425ce2ed | 117 | |
6c8dbf00 | 118 | #define arena_lock(ptr, size) do { \ |
a9da0bb2 | 119 | if (ptr) \ |
cbb47fa1 | 120 | __libc_lock_lock (ptr->mutex); \ |
6c8dbf00 | 121 | else \ |
92a9b22d | 122 | ptr = arena_get2 ((size), NULL); \ |
6c8dbf00 | 123 | } while (0) |
fa8d436c UD |
124 | |
125 | /* find the heap and corresponding arena for a given ptr */ | |
126 | ||
127 | #define heap_for_ptr(ptr) \ | |
6c8dbf00 | 128 | ((heap_info *) ((unsigned long) (ptr) & ~(HEAP_MAX_SIZE - 1))) |
fa8d436c | 129 | #define arena_for_chunk(ptr) \ |
e9c4fe93 | 130 | (chunk_main_arena (ptr) ? &main_arena : heap_for_ptr (ptr)->ar_ptr) |
fa8d436c | 131 | |
fa8d436c UD |
132 | |
133 | /**************************************************************************/ | |
134 | ||
fa8d436c UD |
135 | /* atfork support. */ |
136 | ||
29d79486 FW |
137 | /* The following three functions are called around fork from a |
138 | multi-threaded process. We do not use the general fork handler | |
139 | mechanism to make sure that our handlers are the last ones being | |
140 | called, so that other fork handlers can use the malloc | |
141 | subsystem. */ | |
fa8d436c | 142 | |
29d79486 FW |
143 | void |
144 | __malloc_fork_lock_parent (void) | |
fa8d436c | 145 | { |
6c8dbf00 | 146 | if (__malloc_initialized < 1) |
2a652f5a | 147 | return; |
6c8dbf00 | 148 | |
90c400bd | 149 | /* We do not acquire free_list_lock here because we completely |
29d79486 | 150 | reconstruct free_list in __malloc_fork_unlock_child. */ |
90c400bd | 151 | |
4bf5f222 | 152 | __libc_lock_lock (list_lock); |
7dac9f3d | 153 | |
8a727af9 | 154 | for (mstate ar_ptr = &main_arena;; ) |
6c8dbf00 | 155 | { |
4bf5f222 | 156 | __libc_lock_lock (ar_ptr->mutex); |
6c8dbf00 OB |
157 | ar_ptr = ar_ptr->next; |
158 | if (ar_ptr == &main_arena) | |
159 | break; | |
7dac9f3d | 160 | } |
fa8d436c UD |
161 | } |
162 | ||
29d79486 FW |
163 | void |
164 | __malloc_fork_unlock_parent (void) | |
fa8d436c | 165 | { |
6c8dbf00 | 166 | if (__malloc_initialized < 1) |
2a652f5a | 167 | return; |
6c8dbf00 | 168 | |
8a727af9 | 169 | for (mstate ar_ptr = &main_arena;; ) |
6c8dbf00 | 170 | { |
4bf5f222 | 171 | __libc_lock_unlock (ar_ptr->mutex); |
6c8dbf00 OB |
172 | ar_ptr = ar_ptr->next; |
173 | if (ar_ptr == &main_arena) | |
174 | break; | |
175 | } | |
4bf5f222 | 176 | __libc_lock_unlock (list_lock); |
fa8d436c UD |
177 | } |
178 | ||
29d79486 FW |
179 | void |
180 | __malloc_fork_unlock_child (void) | |
fa8d436c | 181 | { |
6c8dbf00 | 182 | if (__malloc_initialized < 1) |
2a652f5a | 183 | return; |
6c8dbf00 | 184 | |
8a727af9 | 185 | /* Push all arenas to the free list, except thread_arena, which is |
a62719ba | 186 | attached to the current thread. */ |
4bf5f222 | 187 | __libc_lock_init (free_list_lock); |
8a727af9 FW |
188 | if (thread_arena != NULL) |
189 | thread_arena->attached_threads = 1; | |
425ce2ed | 190 | free_list = NULL; |
8a727af9 | 191 | for (mstate ar_ptr = &main_arena;; ) |
6c8dbf00 | 192 | { |
4bf5f222 | 193 | __libc_lock_init (ar_ptr->mutex); |
8a727af9 | 194 | if (ar_ptr != thread_arena) |
6c8dbf00 | 195 | { |
a62719ba FW |
196 | /* This arena is no longer attached to any thread. */ |
197 | ar_ptr->attached_threads = 0; | |
6c8dbf00 OB |
198 | ar_ptr->next_free = free_list; |
199 | free_list = ar_ptr; | |
200 | } | |
201 | ar_ptr = ar_ptr->next; | |
202 | if (ar_ptr == &main_arena) | |
203 | break; | |
425ce2ed | 204 | } |
90c400bd | 205 | |
4bf5f222 | 206 | __libc_lock_init (list_lock); |
fa8d436c UD |
207 | } |
208 | ||
67e58f39 | 209 | #if HAVE_TUNABLES |
67e58f39 | 210 | void |
44330b6d | 211 | TUNABLE_CALLBACK (set_mallopt_check) (tunable_val_t *valp) |
67e58f39 | 212 | { |
8cbc826c | 213 | int32_t value = (int32_t) valp->numval; |
ac3ed168 | 214 | if (value != 0) |
67e58f39 SP |
215 | __malloc_check_init (); |
216 | } | |
217 | ||
44330b6d | 218 | # define TUNABLE_CALLBACK_FNDECL(__name, __type) \ |
67e58f39 SP |
219 | static inline int do_ ## __name (__type value); \ |
220 | void \ | |
44330b6d | 221 | TUNABLE_CALLBACK (__name) (tunable_val_t *valp) \ |
67e58f39 | 222 | { \ |
8cbc826c | 223 | __type value = (__type) (valp)->numval; \ |
67e58f39 SP |
224 | do_ ## __name (value); \ |
225 | } | |
226 | ||
44330b6d SP |
227 | TUNABLE_CALLBACK_FNDECL (set_mmap_threshold, size_t) |
228 | TUNABLE_CALLBACK_FNDECL (set_mmaps_max, int32_t) | |
229 | TUNABLE_CALLBACK_FNDECL (set_top_pad, size_t) | |
230 | TUNABLE_CALLBACK_FNDECL (set_perturb_byte, int32_t) | |
231 | TUNABLE_CALLBACK_FNDECL (set_trim_threshold, size_t) | |
232 | TUNABLE_CALLBACK_FNDECL (set_arena_max, size_t) | |
233 | TUNABLE_CALLBACK_FNDECL (set_arena_test, size_t) | |
d5c3fafc DD |
234 | #if USE_TCACHE |
235 | TUNABLE_CALLBACK_FNDECL (set_tcache_max, size_t) | |
236 | TUNABLE_CALLBACK_FNDECL (set_tcache_count, size_t) | |
237 | TUNABLE_CALLBACK_FNDECL (set_tcache_unsorted_limit, size_t) | |
238 | #endif | |
c48d92b4 | 239 | TUNABLE_CALLBACK_FNDECL (set_mxfast, size_t) |
67e58f39 | 240 | #else |
fa8d436c | 241 | /* Initialization routine. */ |
fa8d436c UD |
242 | #include <string.h> |
243 | extern char **_environ; | |
244 | ||
245 | static char * | |
fa8d436c UD |
246 | next_env_entry (char ***position) |
247 | { | |
248 | char **current = *position; | |
249 | char *result = NULL; | |
250 | ||
251 | while (*current != NULL) | |
252 | { | |
253 | if (__builtin_expect ((*current)[0] == 'M', 0) | |
6c8dbf00 OB |
254 | && (*current)[1] == 'A' |
255 | && (*current)[2] == 'L' | |
256 | && (*current)[3] == 'L' | |
257 | && (*current)[4] == 'O' | |
258 | && (*current)[5] == 'C' | |
259 | && (*current)[6] == '_') | |
260 | { | |
261 | result = &(*current)[7]; | |
fa8d436c | 262 | |
6c8dbf00 OB |
263 | /* Save current position for next visit. */ |
264 | *position = ++current; | |
fa8d436c | 265 | |
6c8dbf00 OB |
266 | break; |
267 | } | |
fa8d436c UD |
268 | |
269 | ++current; | |
270 | } | |
271 | ||
272 | return result; | |
273 | } | |
67e58f39 | 274 | #endif |
fa8d436c | 275 | |
c0f62c56 | 276 | |
22a89187 | 277 | #ifdef SHARED |
c0f62c56 UD |
278 | static void * |
279 | __failing_morecore (ptrdiff_t d) | |
280 | { | |
281 | return (void *) MORECORE_FAILURE; | |
282 | } | |
5f21997b UD |
283 | |
284 | extern struct dl_open_hook *_dl_open_hook; | |
285 | libc_hidden_proto (_dl_open_hook); | |
fde89ad0 RM |
286 | #endif |
287 | ||
fa8d436c | 288 | static void |
06d6611a | 289 | ptmalloc_init (void) |
fa8d436c | 290 | { |
6c8dbf00 OB |
291 | if (__malloc_initialized >= 0) |
292 | return; | |
293 | ||
fa8d436c UD |
294 | __malloc_initialized = 0; |
295 | ||
22a89187 | 296 | #ifdef SHARED |
5f21997b UD |
297 | /* In case this libc copy is in a non-default namespace, never use brk. |
298 | Likewise if dlopened from statically linked program. */ | |
c0f62c56 UD |
299 | Dl_info di; |
300 | struct link_map *l; | |
5f21997b UD |
301 | |
302 | if (_dl_open_hook != NULL | |
303 | || (_dl_addr (ptmalloc_init, &di, &l, NULL) != 0 | |
6c8dbf00 | 304 | && l->l_ns != LM_ID_BASE)) |
c0f62c56 UD |
305 | __morecore = __failing_morecore; |
306 | #endif | |
307 | ||
6782806d | 308 | thread_arena = &main_arena; |
67e58f39 | 309 | |
3381be5c | 310 | malloc_init_state (&main_arena); |
67e58f39 | 311 | |
3381be5c | 312 | #if HAVE_TUNABLES |
44330b6d SP |
313 | TUNABLE_GET (check, int32_t, TUNABLE_CALLBACK (set_mallopt_check)); |
314 | TUNABLE_GET (top_pad, size_t, TUNABLE_CALLBACK (set_top_pad)); | |
315 | TUNABLE_GET (perturb, int32_t, TUNABLE_CALLBACK (set_perturb_byte)); | |
316 | TUNABLE_GET (mmap_threshold, size_t, TUNABLE_CALLBACK (set_mmap_threshold)); | |
317 | TUNABLE_GET (trim_threshold, size_t, TUNABLE_CALLBACK (set_trim_threshold)); | |
318 | TUNABLE_GET (mmap_max, int32_t, TUNABLE_CALLBACK (set_mmaps_max)); | |
319 | TUNABLE_GET (arena_max, size_t, TUNABLE_CALLBACK (set_arena_max)); | |
320 | TUNABLE_GET (arena_test, size_t, TUNABLE_CALLBACK (set_arena_test)); | |
3381be5c | 321 | # if USE_TCACHE |
d5c3fafc DD |
322 | TUNABLE_GET (tcache_max, size_t, TUNABLE_CALLBACK (set_tcache_max)); |
323 | TUNABLE_GET (tcache_count, size_t, TUNABLE_CALLBACK (set_tcache_count)); | |
324 | TUNABLE_GET (tcache_unsorted_limit, size_t, | |
325 | TUNABLE_CALLBACK (set_tcache_unsorted_limit)); | |
3381be5c | 326 | # endif |
c48d92b4 | 327 | TUNABLE_GET (mxfast, size_t, TUNABLE_CALLBACK (set_mxfast)); |
67e58f39 | 328 | #else |
02d46fc4 | 329 | const char *s = NULL; |
a1ffb40e | 330 | if (__glibc_likely (_environ != NULL)) |
08e49216 RM |
331 | { |
332 | char **runp = _environ; | |
333 | char *envline; | |
334 | ||
335 | while (__builtin_expect ((envline = next_env_entry (&runp)) != NULL, | |
6c8dbf00 OB |
336 | 0)) |
337 | { | |
338 | size_t len = strcspn (envline, "="); | |
339 | ||
340 | if (envline[len] != '=') | |
341 | /* This is a "MALLOC_" variable at the end of the string | |
342 | without a '=' character. Ignore it since otherwise we | |
343 | will access invalid memory below. */ | |
344 | continue; | |
345 | ||
346 | switch (len) | |
347 | { | |
348 | case 6: | |
349 | if (memcmp (envline, "CHECK_", 6) == 0) | |
350 | s = &envline[7]; | |
351 | break; | |
352 | case 8: | |
353 | if (!__builtin_expect (__libc_enable_secure, 0)) | |
354 | { | |
355 | if (memcmp (envline, "TOP_PAD_", 8) == 0) | |
356 | __libc_mallopt (M_TOP_PAD, atoi (&envline[9])); | |
357 | else if (memcmp (envline, "PERTURB_", 8) == 0) | |
358 | __libc_mallopt (M_PERTURB, atoi (&envline[9])); | |
359 | } | |
360 | break; | |
361 | case 9: | |
362 | if (!__builtin_expect (__libc_enable_secure, 0)) | |
363 | { | |
364 | if (memcmp (envline, "MMAP_MAX_", 9) == 0) | |
365 | __libc_mallopt (M_MMAP_MAX, atoi (&envline[10])); | |
366 | else if (memcmp (envline, "ARENA_MAX", 9) == 0) | |
367 | __libc_mallopt (M_ARENA_MAX, atoi (&envline[10])); | |
368 | } | |
369 | break; | |
370 | case 10: | |
371 | if (!__builtin_expect (__libc_enable_secure, 0)) | |
372 | { | |
373 | if (memcmp (envline, "ARENA_TEST", 10) == 0) | |
374 | __libc_mallopt (M_ARENA_TEST, atoi (&envline[11])); | |
375 | } | |
376 | break; | |
377 | case 15: | |
378 | if (!__builtin_expect (__libc_enable_secure, 0)) | |
379 | { | |
380 | if (memcmp (envline, "TRIM_THRESHOLD_", 15) == 0) | |
381 | __libc_mallopt (M_TRIM_THRESHOLD, atoi (&envline[16])); | |
382 | else if (memcmp (envline, "MMAP_THRESHOLD_", 15) == 0) | |
383 | __libc_mallopt (M_MMAP_THRESHOLD, atoi (&envline[16])); | |
384 | } | |
385 | break; | |
386 | default: | |
387 | break; | |
388 | } | |
389 | } | |
390 | } | |
ac3ed168 FW |
391 | if (s && s[0] != '\0' && s[0] != '0') |
392 | __malloc_check_init (); | |
67e58f39 SP |
393 | #endif |
394 | ||
2ba3cfa1 | 395 | #if HAVE_MALLOC_INIT_HOOK |
92e1ab0e | 396 | void (*hook) (void) = atomic_forced_read (__malloc_initialize_hook); |
df77455c UD |
397 | if (hook != NULL) |
398 | (*hook)(); | |
2ba3cfa1 | 399 | #endif |
fa8d436c UD |
400 | __malloc_initialized = 1; |
401 | } | |
402 | ||
fa8d436c UD |
403 | /* Managing heaps and arenas (for concurrent threads) */ |
404 | ||
fa8d436c UD |
405 | #if MALLOC_DEBUG > 1 |
406 | ||
407 | /* Print the complete contents of a single heap to stderr. */ | |
408 | ||
409 | static void | |
6c8dbf00 | 410 | dump_heap (heap_info *heap) |
fa8d436c UD |
411 | { |
412 | char *ptr; | |
413 | mchunkptr p; | |
414 | ||
6c8dbf00 OB |
415 | fprintf (stderr, "Heap %p, size %10lx:\n", heap, (long) heap->size); |
416 | ptr = (heap->ar_ptr != (mstate) (heap + 1)) ? | |
417 | (char *) (heap + 1) : (char *) (heap + 1) + sizeof (struct malloc_state); | |
418 | p = (mchunkptr) (((unsigned long) ptr + MALLOC_ALIGN_MASK) & | |
419 | ~MALLOC_ALIGN_MASK); | |
420 | for (;; ) | |
421 | { | |
422 | fprintf (stderr, "chunk %p size %10lx", p, (long) p->size); | |
423 | if (p == top (heap->ar_ptr)) | |
424 | { | |
425 | fprintf (stderr, " (top)\n"); | |
426 | break; | |
427 | } | |
428 | else if (p->size == (0 | PREV_INUSE)) | |
429 | { | |
430 | fprintf (stderr, " (fence)\n"); | |
431 | break; | |
432 | } | |
433 | fprintf (stderr, "\n"); | |
434 | p = next_chunk (p); | |
fa8d436c | 435 | } |
fa8d436c | 436 | } |
fa8d436c UD |
437 | #endif /* MALLOC_DEBUG > 1 */ |
438 | ||
26d550d3 UD |
439 | /* If consecutive mmap (0, HEAP_MAX_SIZE << 1, ...) calls return decreasing |
440 | addresses as opposed to increasing, new_heap would badly fragment the | |
441 | address space. In that case remember the second HEAP_MAX_SIZE part | |
442 | aligned to HEAP_MAX_SIZE from last mmap (0, HEAP_MAX_SIZE << 1, ...) | |
443 | call (if it is already aligned) and try to reuse it next time. We need | |
444 | no locking for it, as kernel ensures the atomicity for us - worst case | |
445 | we'll call mmap (addr, HEAP_MAX_SIZE, ...) for some value of addr in | |
446 | multiple threads, but only one will succeed. */ | |
447 | static char *aligned_heap_area; | |
448 | ||
fa8d436c UD |
449 | /* Create a new heap. size is automatically rounded up to a multiple |
450 | of the page size. */ | |
451 | ||
452 | static heap_info * | |
6c8dbf00 | 453 | new_heap (size_t size, size_t top_pad) |
fa8d436c | 454 | { |
8a35c3fe | 455 | size_t pagesize = GLRO (dl_pagesize); |
fa8d436c UD |
456 | char *p1, *p2; |
457 | unsigned long ul; | |
458 | heap_info *h; | |
459 | ||
6c8dbf00 | 460 | if (size + top_pad < HEAP_MIN_SIZE) |
fa8d436c | 461 | size = HEAP_MIN_SIZE; |
6c8dbf00 | 462 | else if (size + top_pad <= HEAP_MAX_SIZE) |
fa8d436c | 463 | size += top_pad; |
6c8dbf00 | 464 | else if (size > HEAP_MAX_SIZE) |
fa8d436c UD |
465 | return 0; |
466 | else | |
467 | size = HEAP_MAX_SIZE; | |
8a35c3fe | 468 | size = ALIGN_UP (size, pagesize); |
fa8d436c UD |
469 | |
470 | /* A memory region aligned to a multiple of HEAP_MAX_SIZE is needed. | |
471 | No swap space needs to be reserved for the following large | |
472 | mapping (on Linux, this is the case for all non-writable mappings | |
473 | anyway). */ | |
26d550d3 | 474 | p2 = MAP_FAILED; |
6c8dbf00 OB |
475 | if (aligned_heap_area) |
476 | { | |
477 | p2 = (char *) MMAP (aligned_heap_area, HEAP_MAX_SIZE, PROT_NONE, | |
478 | MAP_NORESERVE); | |
479 | aligned_heap_area = NULL; | |
480 | if (p2 != MAP_FAILED && ((unsigned long) p2 & (HEAP_MAX_SIZE - 1))) | |
481 | { | |
482 | __munmap (p2, HEAP_MAX_SIZE); | |
483 | p2 = MAP_FAILED; | |
484 | } | |
26d550d3 | 485 | } |
6c8dbf00 OB |
486 | if (p2 == MAP_FAILED) |
487 | { | |
488 | p1 = (char *) MMAP (0, HEAP_MAX_SIZE << 1, PROT_NONE, MAP_NORESERVE); | |
489 | if (p1 != MAP_FAILED) | |
490 | { | |
491 | p2 = (char *) (((unsigned long) p1 + (HEAP_MAX_SIZE - 1)) | |
492 | & ~(HEAP_MAX_SIZE - 1)); | |
493 | ul = p2 - p1; | |
494 | if (ul) | |
495 | __munmap (p1, ul); | |
496 | else | |
497 | aligned_heap_area = p2 + HEAP_MAX_SIZE; | |
498 | __munmap (p2 + HEAP_MAX_SIZE, HEAP_MAX_SIZE - ul); | |
499 | } | |
26d550d3 | 500 | else |
6c8dbf00 OB |
501 | { |
502 | /* Try to take the chance that an allocation of only HEAP_MAX_SIZE | |
503 | is already aligned. */ | |
504 | p2 = (char *) MMAP (0, HEAP_MAX_SIZE, PROT_NONE, MAP_NORESERVE); | |
505 | if (p2 == MAP_FAILED) | |
506 | return 0; | |
507 | ||
508 | if ((unsigned long) p2 & (HEAP_MAX_SIZE - 1)) | |
509 | { | |
510 | __munmap (p2, HEAP_MAX_SIZE); | |
511 | return 0; | |
512 | } | |
513 | } | |
fa8d436c | 514 | } |
6c8dbf00 OB |
515 | if (__mprotect (p2, size, PROT_READ | PROT_WRITE) != 0) |
516 | { | |
517 | __munmap (p2, HEAP_MAX_SIZE); | |
518 | return 0; | |
519 | } | |
520 | h = (heap_info *) p2; | |
fa8d436c | 521 | h->size = size; |
c7fd3362 | 522 | h->mprotect_size = size; |
322dea08 | 523 | LIBC_PROBE (memory_heap_new, 2, h, h->size); |
fa8d436c UD |
524 | return h; |
525 | } | |
526 | ||
cbf5760e UD |
527 | /* Grow a heap. size is automatically rounded up to a |
528 | multiple of the page size. */ | |
fa8d436c UD |
529 | |
530 | static int | |
6c8dbf00 | 531 | grow_heap (heap_info *h, long diff) |
fa8d436c | 532 | { |
8a35c3fe | 533 | size_t pagesize = GLRO (dl_pagesize); |
fa8d436c UD |
534 | long new_size; |
535 | ||
8a35c3fe | 536 | diff = ALIGN_UP (diff, pagesize); |
6c8dbf00 OB |
537 | new_size = (long) h->size + diff; |
538 | if ((unsigned long) new_size > (unsigned long) HEAP_MAX_SIZE) | |
cbf5760e | 539 | return -1; |
6c8dbf00 OB |
540 | |
541 | if ((unsigned long) new_size > h->mprotect_size) | |
542 | { | |
543 | if (__mprotect ((char *) h + h->mprotect_size, | |
544 | (unsigned long) new_size - h->mprotect_size, | |
545 | PROT_READ | PROT_WRITE) != 0) | |
546 | return -2; | |
547 | ||
548 | h->mprotect_size = new_size; | |
549 | } | |
cbf5760e UD |
550 | |
551 | h->size = new_size; | |
322dea08 | 552 | LIBC_PROBE (memory_heap_more, 2, h, h->size); |
cbf5760e UD |
553 | return 0; |
554 | } | |
555 | ||
556 | /* Shrink a heap. */ | |
557 | ||
558 | static int | |
6c8dbf00 | 559 | shrink_heap (heap_info *h, long diff) |
cbf5760e UD |
560 | { |
561 | long new_size; | |
562 | ||
6c8dbf00 OB |
563 | new_size = (long) h->size - diff; |
564 | if (new_size < (long) sizeof (*h)) | |
cbf5760e | 565 | return -1; |
6c8dbf00 | 566 | |
9fab36eb SP |
567 | /* Try to re-map the extra heap space freshly to save memory, and make it |
568 | inaccessible. See malloc-sysdep.h to know when this is true. */ | |
a1ffb40e | 569 | if (__glibc_unlikely (check_may_shrink_heap ())) |
cbf5760e | 570 | { |
6c8dbf00 OB |
571 | if ((char *) MMAP ((char *) h + new_size, diff, PROT_NONE, |
572 | MAP_FIXED) == (char *) MAP_FAILED) | |
573 | return -2; | |
574 | ||
cbf5760e UD |
575 | h->mprotect_size = new_size; |
576 | } | |
cbf5760e | 577 | else |
6c8dbf00 | 578 | __madvise ((char *) h + new_size, diff, MADV_DONTNEED); |
cbf5760e UD |
579 | /*fprintf(stderr, "shrink %p %08lx\n", h, new_size);*/ |
580 | ||
fa8d436c | 581 | h->size = new_size; |
322dea08 | 582 | LIBC_PROBE (memory_heap_less, 2, h, h->size); |
fa8d436c UD |
583 | return 0; |
584 | } | |
585 | ||
586 | /* Delete a heap. */ | |
587 | ||
26d550d3 | 588 | #define delete_heap(heap) \ |
6c8dbf00 OB |
589 | do { \ |
590 | if ((char *) (heap) + HEAP_MAX_SIZE == aligned_heap_area) \ | |
591 | aligned_heap_area = NULL; \ | |
592 | __munmap ((char *) (heap), HEAP_MAX_SIZE); \ | |
593 | } while (0) | |
fa8d436c UD |
594 | |
595 | static int | |
6c8dbf00 | 596 | heap_trim (heap_info *heap, size_t pad) |
fa8d436c UD |
597 | { |
598 | mstate ar_ptr = heap->ar_ptr; | |
6c8dbf00 | 599 | unsigned long pagesz = GLRO (dl_pagesize); |
1ecba1fa | 600 | mchunkptr top_chunk = top (ar_ptr), p; |
fa8d436c | 601 | heap_info *prev_heap; |
c26efef9 | 602 | long new_size, top_size, top_area, extra, prev_size, misalign; |
fa8d436c UD |
603 | |
604 | /* Can this heap go away completely? */ | |
6c8dbf00 OB |
605 | while (top_chunk == chunk_at_offset (heap, sizeof (*heap))) |
606 | { | |
607 | prev_heap = heap->prev; | |
608 | prev_size = prev_heap->size - (MINSIZE - 2 * SIZE_SZ); | |
609 | p = chunk_at_offset (prev_heap, prev_size); | |
610 | /* fencepost must be properly aligned. */ | |
611 | misalign = ((long) p) & MALLOC_ALIGN_MASK; | |
612 | p = chunk_at_offset (prev_heap, prev_size - misalign); | |
e9c4fe93 | 613 | assert (chunksize_nomask (p) == (0 | PREV_INUSE)); /* must be fencepost */ |
6c8dbf00 OB |
614 | p = prev_chunk (p); |
615 | new_size = chunksize (p) + (MINSIZE - 2 * SIZE_SZ) + misalign; | |
616 | assert (new_size > 0 && new_size < (long) (2 * MINSIZE)); | |
617 | if (!prev_inuse (p)) | |
e9c4fe93 | 618 | new_size += prev_size (p); |
6c8dbf00 OB |
619 | assert (new_size > 0 && new_size < HEAP_MAX_SIZE); |
620 | if (new_size + (HEAP_MAX_SIZE - prev_heap->size) < pad + MINSIZE + pagesz) | |
621 | break; | |
622 | ar_ptr->system_mem -= heap->size; | |
6c8dbf00 OB |
623 | LIBC_PROBE (memory_heap_free, 2, heap, heap->size); |
624 | delete_heap (heap); | |
625 | heap = prev_heap; | |
626 | if (!prev_inuse (p)) /* consolidate backward */ | |
627 | { | |
628 | p = prev_chunk (p); | |
1ecba1fa | 629 | unlink_chunk (ar_ptr, p); |
6c8dbf00 OB |
630 | } |
631 | assert (((unsigned long) ((char *) p + new_size) & (pagesz - 1)) == 0); | |
632 | assert (((char *) p + new_size) == ((char *) heap + heap->size)); | |
633 | top (ar_ptr) = top_chunk = p; | |
634 | set_head (top_chunk, new_size | PREV_INUSE); | |
635 | /*check_chunk(ar_ptr, top_chunk);*/ | |
fa8d436c | 636 | } |
c26efef9 MG |
637 | |
638 | /* Uses similar logic for per-thread arenas as the main arena with systrim | |
e4bc326d CD |
639 | and _int_free by preserving the top pad and rounding down to the nearest |
640 | page. */ | |
6c8dbf00 | 641 | top_size = chunksize (top_chunk); |
e4bc326d CD |
642 | if ((unsigned long)(top_size) < |
643 | (unsigned long)(mp_.trim_threshold)) | |
644 | return 0; | |
645 | ||
c26efef9 | 646 | top_area = top_size - MINSIZE - 1; |
f8ef472c | 647 | if (top_area < 0 || (size_t) top_area <= pad) |
c26efef9 MG |
648 | return 0; |
649 | ||
e4bc326d | 650 | /* Release in pagesize units and round down to the nearest page. */ |
c26efef9 | 651 | extra = ALIGN_DOWN(top_area - pad, pagesz); |
e4bc326d | 652 | if (extra == 0) |
fa8d436c | 653 | return 0; |
6c8dbf00 | 654 | |
fa8d436c | 655 | /* Try to shrink. */ |
6c8dbf00 | 656 | if (shrink_heap (heap, extra) != 0) |
fa8d436c | 657 | return 0; |
6c8dbf00 | 658 | |
fa8d436c | 659 | ar_ptr->system_mem -= extra; |
fa8d436c UD |
660 | |
661 | /* Success. Adjust top accordingly. */ | |
6c8dbf00 | 662 | set_head (top_chunk, (top_size - extra) | PREV_INUSE); |
fa8d436c UD |
663 | /*check_chunk(ar_ptr, top_chunk);*/ |
664 | return 1; | |
665 | } | |
666 | ||
04ec80e4 UD |
667 | /* Create a new arena with initial size "size". */ |
668 | ||
a62719ba | 669 | /* If REPLACED_ARENA is not NULL, detach it from this thread. Must be |
90c400bd | 670 | called while free_list_lock is held. */ |
a62719ba FW |
671 | static void |
672 | detach_arena (mstate replaced_arena) | |
673 | { | |
674 | if (replaced_arena != NULL) | |
675 | { | |
676 | assert (replaced_arena->attached_threads > 0); | |
677 | /* The current implementation only detaches from main_arena in | |
678 | case of allocation failure. This means that it is likely not | |
679 | beneficial to put the arena on free_list even if the | |
680 | reference count reaches zero. */ | |
681 | --replaced_arena->attached_threads; | |
682 | } | |
683 | } | |
684 | ||
04ec80e4 | 685 | static mstate |
6c8dbf00 | 686 | _int_new_arena (size_t size) |
04ec80e4 UD |
687 | { |
688 | mstate a; | |
689 | heap_info *h; | |
690 | char *ptr; | |
691 | unsigned long misalign; | |
692 | ||
6c8dbf00 OB |
693 | h = new_heap (size + (sizeof (*h) + sizeof (*a) + MALLOC_ALIGNMENT), |
694 | mp_.top_pad); | |
695 | if (!h) | |
696 | { | |
697 | /* Maybe size is too large to fit in a single heap. So, just try | |
698 | to create a minimally-sized arena and let _int_malloc() attempt | |
699 | to deal with the large request via mmap_chunk(). */ | |
700 | h = new_heap (sizeof (*h) + sizeof (*a) + MALLOC_ALIGNMENT, mp_.top_pad); | |
701 | if (!h) | |
702 | return 0; | |
703 | } | |
704 | a = h->ar_ptr = (mstate) (h + 1); | |
705 | malloc_init_state (a); | |
a62719ba | 706 | a->attached_threads = 1; |
04ec80e4 UD |
707 | /*a->next = NULL;*/ |
708 | a->system_mem = a->max_system_mem = h->size; | |
04ec80e4 UD |
709 | |
710 | /* Set up the top chunk, with proper alignment. */ | |
6c8dbf00 OB |
711 | ptr = (char *) (a + 1); |
712 | misalign = (unsigned long) chunk2mem (ptr) & MALLOC_ALIGN_MASK; | |
04ec80e4 UD |
713 | if (misalign > 0) |
714 | ptr += MALLOC_ALIGNMENT - misalign; | |
6c8dbf00 OB |
715 | top (a) = (mchunkptr) ptr; |
716 | set_head (top (a), (((char *) h + h->size) - ptr) | PREV_INUSE); | |
04ec80e4 | 717 | |
3ea5be54 | 718 | LIBC_PROBE (memory_arena_new, 2, a, size); |
a62719ba | 719 | mstate replaced_arena = thread_arena; |
6782806d | 720 | thread_arena = a; |
4bf5f222 | 721 | __libc_lock_init (a->mutex); |
425ce2ed | 722 | |
4bf5f222 | 723 | __libc_lock_lock (list_lock); |
425ce2ed UD |
724 | |
725 | /* Add the new arena to the global list. */ | |
726 | a->next = main_arena.next; | |
90c400bd FW |
727 | /* FIXME: The barrier is an attempt to synchronize with read access |
728 | in reused_arena, which does not acquire list_lock while | |
729 | traversing the list. */ | |
425ce2ed UD |
730 | atomic_write_barrier (); |
731 | main_arena.next = a; | |
732 | ||
4bf5f222 | 733 | __libc_lock_unlock (list_lock); |
425ce2ed | 734 | |
4bf5f222 | 735 | __libc_lock_lock (free_list_lock); |
90c400bd | 736 | detach_arena (replaced_arena); |
4bf5f222 | 737 | __libc_lock_unlock (free_list_lock); |
90c400bd FW |
738 | |
739 | /* Lock this arena. NB: Another thread may have been attached to | |
740 | this arena because the arena is now accessible from the | |
741 | main_arena.next list and could have been picked by reused_arena. | |
742 | This can only happen for the last arena created (before the arena | |
743 | limit is reached). At this point, some arena has to be attached | |
744 | to two threads. We could acquire the arena lock before list_lock | |
745 | to make it less likely that reused_arena picks this new arena, | |
29d79486 FW |
746 | but this could result in a deadlock with |
747 | __malloc_fork_lock_parent. */ | |
90c400bd | 748 | |
4bf5f222 | 749 | __libc_lock_lock (a->mutex); |
90c400bd | 750 | |
04ec80e4 UD |
751 | return a; |
752 | } | |
753 | ||
425ce2ed | 754 | |
f88aab5d | 755 | /* Remove an arena from free_list. */ |
425ce2ed UD |
756 | static mstate |
757 | get_free_list (void) | |
758 | { | |
a62719ba | 759 | mstate replaced_arena = thread_arena; |
425ce2ed UD |
760 | mstate result = free_list; |
761 | if (result != NULL) | |
762 | { | |
4bf5f222 | 763 | __libc_lock_lock (free_list_lock); |
425ce2ed UD |
764 | result = free_list; |
765 | if (result != NULL) | |
a62719ba FW |
766 | { |
767 | free_list = result->next_free; | |
768 | ||
3da825ce | 769 | /* The arena will be attached to this thread. */ |
f88aab5d FW |
770 | assert (result->attached_threads == 0); |
771 | result->attached_threads = 1; | |
a62719ba FW |
772 | |
773 | detach_arena (replaced_arena); | |
774 | } | |
4bf5f222 | 775 | __libc_lock_unlock (free_list_lock); |
425ce2ed UD |
776 | |
777 | if (result != NULL) | |
6c8dbf00 OB |
778 | { |
779 | LIBC_PROBE (memory_arena_reuse_free_list, 1, result); | |
4bf5f222 | 780 | __libc_lock_lock (result->mutex); |
6782806d | 781 | thread_arena = result; |
6c8dbf00 | 782 | } |
425ce2ed UD |
783 | } |
784 | ||
785 | return result; | |
786 | } | |
787 | ||
f88aab5d FW |
788 | /* Remove the arena from the free list (if it is present). |
789 | free_list_lock must have been acquired by the caller. */ | |
790 | static void | |
791 | remove_from_free_list (mstate arena) | |
792 | { | |
793 | mstate *previous = &free_list; | |
794 | for (mstate p = free_list; p != NULL; p = p->next_free) | |
795 | { | |
796 | assert (p->attached_threads == 0); | |
797 | if (p == arena) | |
798 | { | |
799 | /* Remove the requested arena from the list. */ | |
800 | *previous = p->next_free; | |
801 | break; | |
802 | } | |
803 | else | |
804 | previous = &p->next_free; | |
805 | } | |
806 | } | |
807 | ||
77480c6b | 808 | /* Lock and return an arena that can be reused for memory allocation. |
bf51f568 JL |
809 | Avoid AVOID_ARENA as we have already failed to allocate memory in |
810 | it and it is currently locked. */ | |
425ce2ed | 811 | static mstate |
bf51f568 | 812 | reused_arena (mstate avoid_arena) |
425ce2ed | 813 | { |
425ce2ed | 814 | mstate result; |
90c400bd | 815 | /* FIXME: Access to next_to_use suffers from data races. */ |
425ce2ed UD |
816 | static mstate next_to_use; |
817 | if (next_to_use == NULL) | |
818 | next_to_use = &main_arena; | |
819 | ||
3da825ce FW |
820 | /* Iterate over all arenas (including those linked from |
821 | free_list). */ | |
425ce2ed UD |
822 | result = next_to_use; |
823 | do | |
824 | { | |
a9da0bb2 | 825 | if (!__libc_lock_trylock (result->mutex)) |
6c8dbf00 | 826 | goto out; |
425ce2ed | 827 | |
90c400bd | 828 | /* FIXME: This is a data race, see _int_new_arena. */ |
425ce2ed UD |
829 | result = result->next; |
830 | } | |
831 | while (result != next_to_use); | |
832 | ||
bf51f568 JL |
833 | /* Avoid AVOID_ARENA as we have already failed to allocate memory |
834 | in that arena and it is currently locked. */ | |
835 | if (result == avoid_arena) | |
836 | result = result->next; | |
837 | ||
fff94fa2 | 838 | /* No arena available without contention. Wait for the next in line. */ |
6999d38c | 839 | LIBC_PROBE (memory_arena_reuse_wait, 3, &result->mutex, result, avoid_arena); |
4bf5f222 | 840 | __libc_lock_lock (result->mutex); |
425ce2ed | 841 | |
6c8dbf00 | 842 | out: |
f88aab5d | 843 | /* Attach the arena to the current thread. */ |
a62719ba | 844 | { |
90c400bd | 845 | /* Update the arena thread attachment counters. */ |
a62719ba | 846 | mstate replaced_arena = thread_arena; |
4bf5f222 | 847 | __libc_lock_lock (free_list_lock); |
a62719ba | 848 | detach_arena (replaced_arena); |
f88aab5d FW |
849 | |
850 | /* We may have picked up an arena on the free list. We need to | |
851 | preserve the invariant that no arena on the free list has a | |
852 | positive attached_threads counter (otherwise, | |
853 | arena_thread_freeres cannot use the counter to determine if the | |
854 | arena needs to be put on the free list). We unconditionally | |
855 | remove the selected arena from the free list. The caller of | |
856 | reused_arena checked the free list and observed it to be empty, | |
857 | so the list is very short. */ | |
858 | remove_from_free_list (result); | |
859 | ||
a62719ba | 860 | ++result->attached_threads; |
f88aab5d | 861 | |
4bf5f222 | 862 | __libc_lock_unlock (free_list_lock); |
a62719ba FW |
863 | } |
864 | ||
6999d38c | 865 | LIBC_PROBE (memory_arena_reuse, 2, result, avoid_arena); |
6782806d | 866 | thread_arena = result; |
425ce2ed UD |
867 | next_to_use = result->next; |
868 | ||
869 | return result; | |
870 | } | |
425ce2ed | 871 | |
fa8d436c | 872 | static mstate |
92a9b22d | 873 | arena_get2 (size_t size, mstate avoid_arena) |
fa8d436c UD |
874 | { |
875 | mstate a; | |
fa8d436c | 876 | |
77cdc054 AS |
877 | static size_t narenas_limit; |
878 | ||
879 | a = get_free_list (); | |
880 | if (a == NULL) | |
881 | { | |
882 | /* Nothing immediately available, so generate a new arena. */ | |
883 | if (narenas_limit == 0) | |
6c8dbf00 OB |
884 | { |
885 | if (mp_.arena_max != 0) | |
886 | narenas_limit = mp_.arena_max; | |
887 | else if (narenas > mp_.arena_test) | |
888 | { | |
889 | int n = __get_nprocs (); | |
890 | ||
891 | if (n >= 1) | |
892 | narenas_limit = NARENAS_FROM_NCORES (n); | |
893 | else | |
894 | /* We have no information about the system. Assume two | |
895 | cores. */ | |
896 | narenas_limit = NARENAS_FROM_NCORES (2); | |
897 | } | |
898 | } | |
77cdc054 AS |
899 | repeat:; |
900 | size_t n = narenas; | |
41b81892 | 901 | /* NB: the following depends on the fact that (size_t)0 - 1 is a |
6c8dbf00 OB |
902 | very large number and that the underflow is OK. If arena_max |
903 | is set the value of arena_test is irrelevant. If arena_test | |
904 | is set but narenas is not yet larger or equal to arena_test | |
905 | narenas_limit is 0. There is no possibility for narenas to | |
906 | be too big for the test to always fail since there is not | |
907 | enough address space to create that many arenas. */ | |
a1ffb40e | 908 | if (__glibc_unlikely (n <= narenas_limit - 1)) |
6c8dbf00 OB |
909 | { |
910 | if (catomic_compare_and_exchange_bool_acq (&narenas, n + 1, n)) | |
911 | goto repeat; | |
912 | a = _int_new_arena (size); | |
a1ffb40e | 913 | if (__glibc_unlikely (a == NULL)) |
6c8dbf00 OB |
914 | catomic_decrement (&narenas); |
915 | } | |
a5fb313c | 916 | else |
6c8dbf00 | 917 | a = reused_arena (avoid_arena); |
77cdc054 | 918 | } |
fa8d436c UD |
919 | return a; |
920 | } | |
921 | ||
c78ab094 SP |
922 | /* If we don't have the main arena, then maybe the failure is due to running |
923 | out of mmapped areas, so we can try allocating on the main arena. | |
924 | Otherwise, it is likely that sbrk() has failed and there is still a chance | |
925 | to mmap(), so try one of the other arenas. */ | |
926 | static mstate | |
927 | arena_get_retry (mstate ar_ptr, size_t bytes) | |
928 | { | |
655673f3 | 929 | LIBC_PROBE (memory_arena_retry, 2, bytes, ar_ptr); |
6c8dbf00 OB |
930 | if (ar_ptr != &main_arena) |
931 | { | |
4bf5f222 | 932 | __libc_lock_unlock (ar_ptr->mutex); |
6c8dbf00 | 933 | ar_ptr = &main_arena; |
4bf5f222 | 934 | __libc_lock_lock (ar_ptr->mutex); |
6c8dbf00 OB |
935 | } |
936 | else | |
937 | { | |
4bf5f222 | 938 | __libc_lock_unlock (ar_ptr->mutex); |
92a9b22d | 939 | ar_ptr = arena_get2 (bytes, ar_ptr); |
6c8dbf00 | 940 | } |
c78ab094 SP |
941 | |
942 | return ar_ptr; | |
943 | } | |
944 | ||
124e0258 FW |
945 | void |
946 | __malloc_arena_thread_freeres (void) | |
425ce2ed | 947 | { |
0a947e06 FW |
948 | /* Shut down the thread cache first. This could deallocate data for |
949 | the thread arena, so do this before we put the arena on the free | |
950 | list. */ | |
951 | tcache_thread_shutdown (); | |
952 | ||
6782806d FW |
953 | mstate a = thread_arena; |
954 | thread_arena = NULL; | |
425ce2ed UD |
955 | |
956 | if (a != NULL) | |
957 | { | |
4bf5f222 | 958 | __libc_lock_lock (free_list_lock); |
a62719ba FW |
959 | /* If this was the last attached thread for this arena, put the |
960 | arena on the free list. */ | |
961 | assert (a->attached_threads > 0); | |
962 | if (--a->attached_threads == 0) | |
963 | { | |
964 | a->next_free = free_list; | |
965 | free_list = a; | |
966 | } | |
4bf5f222 | 967 | __libc_lock_unlock (free_list_lock); |
425ce2ed UD |
968 | } |
969 | } | |
425ce2ed | 970 | |
fa8d436c UD |
971 | /* |
972 | * Local variables: | |
973 | * c-basic-offset: 2 | |
974 | * End: | |
975 | */ |