2 * Copyright (c) 2000-2005 by Hewlett-Packard Company. All rights reserved.
4 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
5 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
7 * Permission is hereby granted to use or copy this program
8 * for any purpose, provided the above notices are retained on all copies.
9 * Permission to modify the code and to distribute modified code is granted,
10 * provided the above notices are retained, and a notice that the code was
11 * modified is included with the above copyright notice.
13 #include "private/gc_priv.h"
15 # if defined(THREAD_LOCAL_ALLOC)
17 #include "private/thread_local_alloc.h"
18 #include "gc_inline.h"
22 #if defined(USE_COMPILER_TLS)
24 #elif defined(USE_WIN32_COMPILER_TLS)
27 GC_key_t GC_thread_key;
29 static GC_bool keys_initialized;
31 /* Return a single nonempty freelist fl to the global one pointed to */
34 static void return_single_freelist(void *fl, void **gfl)
41 GC_ASSERT(GC_size(fl) == GC_size(*gfl));
43 qptr = &(obj_link(fl));
44 while ((word)(q = *qptr) >= HBLKSIZE)
45 qptr = &(obj_link(q));
52 /* Recover the contents of the freelist array fl into the global one gfl.*/
53 /* We hold the allocator lock. */
54 static void return_freelists(void **fl, void **gfl)
58 for (i = 1; i < TINY_FREELISTS; ++i) {
59 if ((word)(fl[i]) >= HBLKSIZE) {
60 return_single_freelist(fl[i], gfl+i);
62 /* Clear fl[i], since the thread structure may hang around. */
63 /* Do it in a way that is likely to trap if we access it. */
64 fl[i] = (ptr_t)HBLKSIZE;
66 /* The 0 granule freelist really contains 1 granule objects. */
67 # ifdef GC_GCJ_SUPPORT
68 if (fl[0] == ERROR_FL) return;
70 if ((word)(fl[0]) >= HBLKSIZE) {
71 return_single_freelist(fl[0], gfl+1);
75 /* Each thread structure must be initialized. */
76 /* This call must be made from the new thread. */
77 void GC_init_thread_local(GC_tlfs p)
81 GC_ASSERT(I_HOLD_LOCK());
82 if (!keys_initialized) {
83 if (0 != GC_key_create(&GC_thread_key, 0)) {
84 ABORT("Failed to create key for local allocator");
86 keys_initialized = TRUE;
88 if (0 != GC_setspecific(GC_thread_key, p)) {
89 ABORT("Failed to set thread specific allocation pointers");
91 for (i = 1; i < TINY_FREELISTS; ++i) {
92 p -> ptrfree_freelists[i] = (void *)(word)1;
93 p -> normal_freelists[i] = (void *)(word)1;
94 # ifdef GC_GCJ_SUPPORT
95 p -> gcj_freelists[i] = (void *)(word)1;
98 /* Set up the size 0 free lists. */
99 /* We now handle most of them like regular free lists, to ensure */
100 /* That explicit deallocation works. However, allocation of a */
101 /* size 0 "gcj" object is always an error. */
102 p -> ptrfree_freelists[0] = (void *)(word)1;
103 p -> normal_freelists[0] = (void *)(word)1;
104 # ifdef GC_GCJ_SUPPORT
105 p -> gcj_freelists[0] = ERROR_FL;
109 #ifdef GC_GCJ_SUPPORT
110 extern void ** GC_gcjobjfreelist;
113 /* We hold the allocator lock. */
114 void GC_destroy_thread_local(GC_tlfs p)
116 /* We currently only do this from the thread itself or from */
117 /* the fork handler for a child process. */
119 GC_ASSERT(GC_getspecific(GC_thread_key) == (void *)p);
121 return_freelists(p -> ptrfree_freelists, GC_aobjfreelist);
122 return_freelists(p -> normal_freelists, GC_objfreelist);
123 # ifdef GC_GCJ_SUPPORT
124 return_freelists(p -> gcj_freelists, GC_gcjobjfreelist);
128 #if defined(GC_ASSERTIONS) && defined(GC_PTHREADS) && !defined(CYGWIN32) \
129 && !defined(GC_WIN32_PTHREADS)
130 # include <pthread.h>
131 extern char * GC_lookup_thread(pthread_t id);
134 #if defined(GC_ASSERTIONS) && defined(GC_WIN32_THREADS)
135 void * /*GC_thread*/ GC_lookup_thread_inner(unsigned /*DWORD*/ thread_id);
138 GC_API void * GC_CALL GC_malloc(size_t bytes)
140 size_t granules = ROUNDED_UP_GRANULES(bytes);
145 # if !defined(USE_PTHREAD_SPECIFIC) && !defined(USE_WIN32_SPECIFIC)
146 GC_key_t k = GC_thread_key;
147 if (EXPECT(0 == k, 0)) {
148 /* We haven't yet run GC_init_parallel. That means */
149 /* we also aren't locking, so this is fairly cheap. */
150 return GC_core_malloc(bytes);
152 tsd = GC_getspecific(k);
154 tsd = GC_getspecific(GC_thread_key);
156 # if defined(USE_PTHREAD_SPECIFIC) || defined(USE_WIN32_SPECIFIC)
157 if (EXPECT(0 == tsd, 0)) {
158 return GC_core_malloc(bytes);
161 GC_ASSERT(GC_is_initialized);
162 # ifdef GC_ASSERTIONS
163 /* We can't check tsd correctly, since we don't have access to */
164 /* the right declarations. But we can check that it's close. */
167 # if defined(GC_WIN32_THREADS)
168 char * me = (char *)GC_lookup_thread_inner(GetCurrentThreadId());
170 char * me = GC_lookup_thread(pthread_self());
172 GC_ASSERT((char *)tsd > me && (char *)tsd < me + 1000);
176 tiny_fl = ((GC_tlfs)tsd) -> normal_freelists;
177 GC_FAST_MALLOC_GRANS(result, granules, tiny_fl, DIRECT_GRANULES,
178 NORMAL, GC_core_malloc(bytes), obj_link(result)=0);
180 GC_err_printf("GC_malloc(%u) = %p : %u\n",
181 (unsigned)bytes, result, (unsigned)GC_gc_no);
186 GC_API void * GC_CALL GC_malloc_atomic(size_t bytes)
188 size_t granules = ROUNDED_UP_GRANULES(bytes);
193 # if !defined(USE_PTHREAD_SPECIFIC) && !defined(USE_WIN32_SPECIFIC)
194 GC_key_t k = GC_thread_key;
195 if (EXPECT(0 == k, 0)) {
196 /* We haven't yet run GC_init_parallel. That means */
197 /* we also aren't locking, so this is fairly cheap. */
198 return GC_core_malloc(bytes);
200 tsd = GC_getspecific(k);
202 tsd = GC_getspecific(GC_thread_key);
204 # if defined(USE_PTHREAD_SPECIFIC) || defined(USE_WIN32_SPECIFIC)
205 if (EXPECT(0 == tsd, 0)) {
206 return GC_core_malloc(bytes);
209 GC_ASSERT(GC_is_initialized);
210 tiny_fl = ((GC_tlfs)tsd) -> ptrfree_freelists;
211 GC_FAST_MALLOC_GRANS(result, granules, tiny_fl, DIRECT_GRANULES, PTRFREE,
212 GC_core_malloc_atomic(bytes), (void)0 /* no init */);
216 #ifdef GC_GCJ_SUPPORT
218 #include "include/gc_gcj.h"
221 extern GC_bool GC_gcj_malloc_initialized;
224 extern int GC_gcj_kind;
226 /* Gcj-style allocation without locks is extremely tricky. The */
227 /* fundamental issue is that we may end up marking a free list, which */
228 /* has freelist links instead of "vtable" pointers. That is usually */
229 /* OK, since the next object on the free list will be cleared, and */
230 /* will thus be interpreted as containing a zero descriptor. That's */
231 /* fine if the object has not yet been initialized. But there are */
232 /* interesting potential races. */
233 /* In the case of incremental collection, this seems hopeless, since */
234 /* the marker may run asynchronously, and may pick up the pointer to */
235 /* the next freelist entry (which it thinks is a vtable pointer), get */
236 /* suspended for a while, and then see an allocated object instead */
237 /* of the vtable. This made be avoidable with either a handshake with */
238 /* the collector or, probably more easily, by moving the free list */
239 /* links to the second word of each object. The latter isn't a */
240 /* universal win, since on architecture like Itanium, nonzero offsets */
241 /* are not necessarily free. And there may be cache fill order issues. */
242 /* For now, we punt with incremental GC. This probably means that */
243 /* incremental GC should be enabled before we fork a second thread. */
244 /* Unlike the other thread local allocation calls, we assume that the */
245 /* collector has been explicitly initialized. */
246 GC_API void * GC_CALL GC_gcj_malloc(size_t bytes,
247 void * ptr_to_struct_containing_descr)
249 if (GC_EXPECT(GC_incremental, 0)) {
250 return GC_core_gcj_malloc(bytes, ptr_to_struct_containing_descr);
252 size_t granules = ROUNDED_UP_GRANULES(bytes);
254 void **tiny_fl = ((GC_tlfs)GC_getspecific(GC_thread_key))
256 GC_ASSERT(GC_gcj_malloc_initialized);
257 GC_FAST_MALLOC_GRANS(result, granules, tiny_fl, DIRECT_GRANULES,
259 GC_core_gcj_malloc(bytes,
260 ptr_to_struct_containing_descr),
261 {AO_compiler_barrier();
262 *(void **)result = ptr_to_struct_containing_descr;});
263 /* This forces the initialization of the "method ptr". */
264 /* This is necessary to ensure some very subtle properties */
265 /* required if a GC is run in the middle of such an allocation. */
266 /* Here we implicitly also assume atomicity for the free list. */
267 /* and method pointer assignments. */
268 /* We must update the freelist before we store the pointer. */
269 /* Otherwise a GC at this point would see a corrupted */
271 /* A real memory barrier is not needed, since the */
272 /* action of stopping this thread will cause prior writes */
274 /* We assert that any concurrent marker will stop us. */
275 /* Thus it is impossible for a mark procedure to see the */
276 /* allocation of the next object, but to see this object */
277 /* still containing a free list pointer. Otherwise the */
278 /* marker, by misinterpreting the freelist link as a vtable */
279 /* pointer, might find a random "mark descriptor" in the next */
285 #endif /* GC_GCJ_SUPPORT */
287 /* The thread support layer must arrange to mark thread-local */
288 /* free lists explicitly, since the link field is often */
289 /* invisible to the marker. It knows how to find all threads; */
290 /* we take care of an individual thread freelist structure. */
291 void GC_mark_thread_local_fls_for(GC_tlfs p)
296 for (j = 0; j < TINY_FREELISTS; ++j) {
297 q = p -> ptrfree_freelists[j];
298 if ((word)q > HBLKSIZE) GC_set_fl_marks(q);
299 q = p -> normal_freelists[j];
300 if ((word)q > HBLKSIZE) GC_set_fl_marks(q);
301 # ifdef GC_GCJ_SUPPORT
303 q = p -> gcj_freelists[j];
304 if ((word)q > HBLKSIZE) GC_set_fl_marks(q);
306 # endif /* GC_GCJ_SUPPORT */
310 #if defined(GC_ASSERTIONS)
311 /* Check that all thread-local free-lists in p are completely marked. */
312 void GC_check_tls_for(GC_tlfs p)
317 for (j = 1; j < TINY_FREELISTS; ++j) {
318 q = p -> ptrfree_freelists[j];
319 if ((word)q > HBLKSIZE) GC_check_fl_marks(q);
320 q = p -> normal_freelists[j];
321 if ((word)q > HBLKSIZE) GC_check_fl_marks(q);
322 # ifdef GC_GCJ_SUPPORT
323 q = p -> gcj_freelists[j];
324 if ((word)q > HBLKSIZE) GC_check_fl_marks(q);
325 # endif /* GC_GCJ_SUPPORT */
328 #endif /* GC_ASSERTIONS */
330 # endif /* THREAD_LOCAL_ALLOC */