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.
16 #include "private/gc_priv.h"
18 # if defined(THREAD_LOCAL_ALLOC)
20 #include "private/thread_local_alloc.h"
21 #include "gc_inline.h"
25 #if defined(USE_COMPILER_TLS)
27 #elif defined(USE_WIN32_COMPILER_TLS)
30 GC_key_t GC_thread_key;
32 static GC_bool keys_initialized;
34 /* Return a single nonempty freelist fl to the global one pointed to */
37 static void return_single_freelist(void *fl, void **gfl)
44 GC_ASSERT(GC_size(fl) == GC_size(*gfl));
46 for (qptr = &(obj_link(fl)), q = *qptr;
47 (word)q >= HBLKSIZE; qptr = &(obj_link(q)), q = *qptr);
54 /* Recover the contents of the freelist array fl into the global one gfl.*/
55 /* We hold the allocator lock. */
56 static void return_freelists(void **fl, void **gfl)
60 for (i = 1; i < TINY_FREELISTS; ++i) {
61 if ((word)(fl[i]) >= HBLKSIZE) {
62 return_single_freelist(fl[i], gfl+i);
64 /* Clear fl[i], since the thread structure may hang around. */
65 /* Do it in a way that is likely to trap if we access it. */
66 fl[i] = (ptr_t)HBLKSIZE;
68 /* The 0 granule freelist really contains 1 granule objects. */
69 # ifdef GC_GCJ_SUPPORT
70 if (fl[0] == ERROR_FL) return;
72 if ((word)(fl[0]) >= HBLKSIZE) {
73 return_single_freelist(fl[0], gfl+1);
77 /* Each thread structure must be initialized. */
78 /* This call must be made from the new thread. */
79 /* Caller holds allocation lock. */
80 void GC_init_thread_local(GC_tlfs p)
84 if (!keys_initialized) {
85 if (0 != GC_key_create(&GC_thread_key, 0)) {
86 ABORT("Failed to create key for local allocator");
88 keys_initialized = TRUE;
90 if (0 != GC_setspecific(GC_thread_key, p)) {
91 ABORT("Failed to set thread specific allocation pointers");
93 for (i = 1; i < TINY_FREELISTS; ++i) {
94 p -> ptrfree_freelists[i] = (void *)1;
95 p -> normal_freelists[i] = (void *)1;
96 # ifdef GC_GCJ_SUPPORT
97 p -> gcj_freelists[i] = (void *)1;
100 /* Set up the size 0 free lists. */
101 /* We now handle most of them like regular free lists, to ensure */
102 /* That explicit deallocation works. However, allocation of a */
103 /* size 0 "gcj" object is always an error. */
104 p -> ptrfree_freelists[0] = (void *)1;
105 p -> normal_freelists[0] = (void *)1;
106 # ifdef GC_GCJ_SUPPORT
107 p -> gcj_freelists[0] = ERROR_FL;
111 #ifdef GC_GCJ_SUPPORT
112 extern void ** GC_gcjobjfreelist;
115 /* We hold the allocator lock. */
116 void GC_destroy_thread_local(GC_tlfs p)
118 /* We currently only do this from the thread itself or from */
119 /* the fork handler for a child process. */
121 GC_ASSERT(GC_getspecific(GC_thread_key) == (void *)p);
123 return_freelists(p -> ptrfree_freelists, GC_aobjfreelist);
124 return_freelists(p -> normal_freelists, GC_objfreelist);
125 # ifdef GC_GCJ_SUPPORT
126 return_freelists(p -> gcj_freelists, GC_gcjobjfreelist);
130 #if defined(GC_ASSERTIONS) && defined(GC_PTHREADS) && !defined(CYGWIN32) \
131 && !defined(GC_WIN32_PTHREADS)
132 # include <pthread.h>
133 extern char * GC_lookup_thread(pthread_t id);
136 #if defined(GC_ASSERTIONS) && defined(GC_WIN32_THREADS)
137 extern char * GC_lookup_thread(int id);
140 void * GC_malloc(size_t bytes)
142 size_t granules = ROUNDED_UP_GRANULES(bytes);
147 # if defined(REDIRECT_MALLOC) && !defined(USE_PTHREAD_SPECIFIC)
148 GC_key_t k = GC_thread_key;
149 if (EXPECT(0 == k, 0)) {
150 /* We haven't yet run GC_init_parallel. That means */
151 /* we also aren't locking, so this is fairly cheap. */
152 return GC_core_malloc(bytes);
154 tsd = GC_getspecific(k);
156 GC_ASSERT(GC_is_initialized);
157 tsd = GC_getspecific(GC_thread_key);
159 # if defined(REDIRECT_MALLOC) && defined(USE_PTHREAD_SPECIFIC)
160 if (EXPECT(NULL == tsd, 0)) {
161 return GC_core_malloc(bytes);
164 # ifdef GC_ASSERTIONS
165 /* We can't check tsd correctly, since we don't have access to */
166 /* the right declarations. But we can check that it's close. */
169 # if defined(GC_WIN32_THREADS)
170 char * me = (char *)GC_lookup_thread_inner(GetCurrentThreadId());
172 char * me = GC_lookup_thread(pthread_self());
174 GC_ASSERT((char *)tsd > me && (char *)tsd < me + 1000);
178 tiny_fl = ((GC_tlfs)tsd) -> normal_freelists;
179 GC_FAST_MALLOC_GRANS(result, granules, tiny_fl, DIRECT_GRANULES,
180 NORMAL, GC_core_malloc(bytes), obj_link(result)=0);
184 void * GC_malloc_atomic(size_t bytes)
186 size_t granules = ROUNDED_UP_GRANULES(bytes);
190 GC_ASSERT(GC_is_initialized);
191 tiny_fl = ((GC_tlfs)GC_getspecific(GC_thread_key))
192 -> ptrfree_freelists;
193 GC_FAST_MALLOC_GRANS(result, bytes, tiny_fl, DIRECT_GRANULES,
194 PTRFREE, GC_core_malloc_atomic(bytes), 0/* no init */);
198 #ifdef GC_GCJ_SUPPORT
200 #include "include/gc_gcj.h"
203 extern GC_bool GC_gcj_malloc_initialized;
206 extern int GC_gcj_kind;
208 /* Gcj-style allocation without locks is extremely tricky. The */
209 /* fundamental issue is that we may end up marking a free list, which */
210 /* has freelist links instead of "vtable" pointers. That is usually */
211 /* OK, since the next object on the free list will be cleared, and */
212 /* will thus be interpreted as containg a zero descriptor. That's fine */
213 /* if the object has not yet been initialized. But there are */
214 /* interesting potential races. */
215 /* In the case of incremental collection, this seems hopeless, since */
216 /* the marker may run asynchronously, and may pick up the pointer to */
217 /* the next freelist entry (which it thinks is a vtable pointer), get */
218 /* suspended for a while, and then see an allocated object instead */
219 /* of the vtable. This made be avoidable with either a handshake with */
220 /* the collector or, probably more easily, by moving the free list */
221 /* links to the second word of each object. The latter isn't a */
222 /* universal win, since on architecture like Itanium, nonzero offsets */
223 /* are not necessarily free. And there may be cache fill order issues. */
224 /* For now, we punt with incremental GC. This probably means that */
225 /* incremental GC should be enabled before we fork a second thread. */
226 void * GC_gcj_malloc(size_t bytes,
227 void * ptr_to_struct_containing_descr)
229 if (GC_EXPECT(GC_incremental, 0)) {
230 return GC_core_gcj_malloc(bytes, ptr_to_struct_containing_descr);
232 size_t granules = ROUNDED_UP_GRANULES(bytes);
234 void **tiny_fl = ((GC_tlfs)GC_getspecific(GC_thread_key))
236 GC_ASSERT(GC_gcj_malloc_initialized);
237 GC_FAST_MALLOC_GRANS(result, bytes, tiny_fl, DIRECT_GRANULES,
239 GC_core_gcj_malloc(bytes,
240 ptr_to_struct_containing_descr),
241 {AO_compiler_barrier();
242 *(void **)result = ptr_to_struct_containing_descr;});
243 /* This forces the initialization of the "method ptr". */
244 /* This is necessary to ensure some very subtle properties */
245 /* required if a GC is run in the middle of such an allocation. */
246 /* Here we implicitly also assume atomicity for the free list. */
247 /* and method pointer assignments. */
248 /* We must update the freelist before we store the pointer. */
249 /* Otherwise a GC at this point would see a corrupted */
251 /* A real memory barrier is not needed, since the */
252 /* action of stopping this thread will cause prior writes */
254 /* We assert that any concurrent marker will stop us. */
255 /* Thus it is impossible for a mark procedure to see the */
256 /* allocation of the next object, but to see this object */
257 /* still containing a free list pointer. Otherwise the */
258 /* marker, by misinterpreting the freelist link as a vtable */
259 /* pointer, might find a random "mark descriptor" in the next */
265 #endif /* GC_GCJ_SUPPORT */
267 /* The thread support layer must arrange to mark thread-local */
268 /* free lists explicitly, since the link field is often */
269 /* invisible to the marker. It knows hoe to find all threads; */
270 /* we take care of an individual thread freelist structure. */
271 void GC_mark_thread_local_fls_for(GC_tlfs p)
276 for (j = 1; j < TINY_FREELISTS; ++j) {
277 q = p -> ptrfree_freelists[j];
278 if ((word)q > HBLKSIZE) GC_set_fl_marks(q);
279 q = p -> normal_freelists[j];
280 if ((word)q > HBLKSIZE) GC_set_fl_marks(q);
281 # ifdef GC_GCJ_SUPPORT
282 q = p -> gcj_freelists[j];
283 if ((word)q > HBLKSIZE) GC_set_fl_marks(q);
284 # endif /* GC_GCJ_SUPPORT */
288 #if defined(GC_ASSERTIONS)
289 /* Check that all thread-local free-lists in p are completely marked. */
290 void GC_check_tls_for(GC_tlfs p)
295 for (j = 1; j < TINY_FREELISTS; ++j) {
296 q = p -> ptrfree_freelists[j];
297 if ((word)q > HBLKSIZE) GC_check_fl_marks(q);
298 q = p -> normal_freelists[j];
299 if ((word)q > HBLKSIZE) GC_check_fl_marks(q);
300 # ifdef GC_GCJ_SUPPORT
301 q = p -> gcj_freelists[j];
302 if ((word)q > HBLKSIZE) GC_check_fl_marks(q);
303 # endif /* GC_GCJ_SUPPORT */
306 #endif /* GC_ASSERTIONS */
308 # else /* !THREAD_LOCAL_ALLOC */
310 # define GC_destroy_thread_local(t)
312 # endif /* !THREAD_LOCAL_ALLOC */