2 * mono-threads.c: Low-level threading
5 * Rodrigo Kumpera (kumpera@gmail.com)
7 * Copyright 2011 Novell, Inc (http://www.novell.com)
8 * Copyright 2011 Xamarin, Inc (http://www.xamarin.com)
13 #include <mono/utils/mono-compiler.h>
14 #include <mono/utils/mono-semaphore.h>
15 #include <mono/utils/mono-threads.h>
16 #include <mono/utils/mono-tls.h>
17 #include <mono/utils/hazard-pointer.h>
18 #include <mono/utils/mono-memory-model.h>
19 #include <mono/utils/mono-mmap.h>
20 #include <mono/utils/atomic.h>
21 #include <mono/utils/mono-time.h>
27 #include <mono/utils/mach-support.h>
31 Mutex that makes sure only a single thread can be suspending others.
32 Suspend is a very racy operation since it requires restarting until
33 the target thread is not on an unsafe region.
35 We could implement this using critical regions, but would be much much
36 harder for an operation that is hardly performance critical.
38 The GC has to acquire this lock before starting a STW to make sure
39 a runtime suspend won't make it wronly see a thread in a safepoint
40 when it is in fact not.
42 static MonoSemType global_suspend_semaphore;
44 static size_t thread_info_size;
45 static MonoThreadInfoCallbacks threads_callbacks;
46 static MonoThreadInfoRuntimeCallbacks runtime_callbacks;
47 static MonoNativeTlsKey thread_info_key, thread_exited_key;
49 static __thread guint32 tls_small_id MONO_TLS_FAST;
51 static MonoNativeTlsKey small_id_key;
53 static MonoLinkedListSet thread_list;
54 static gboolean mono_threads_inited = FALSE;
56 static MonoSemType suspend_semaphore;
57 static size_t pending_suspends;
58 static gboolean unified_suspend_enabled;
60 #define mono_thread_info_run_state(info) (((MonoThreadInfo*)info)->thread_state & THREAD_STATE_MASK)
63 #define SLEEP_DURATION_BEFORE_WARNING (10)
65 #define SLEEP_DURATION_BEFORE_ABORT 200
67 static int suspend_posts, resume_posts, abort_posts, waits_done, pending_ops;
70 mono_threads_notify_initiator_of_abort (MonoThreadInfo* info)
72 THREADS_SUSPEND_DEBUG ("[INITIATOR-NOTIFY-ABORT] %p\n", mono_thread_info_get_tid (info));
73 MONO_SEM_POST (&suspend_semaphore);
74 InterlockedIncrement (&abort_posts);
78 mono_threads_notify_initiator_of_suspend (MonoThreadInfo* info)
80 THREADS_SUSPEND_DEBUG ("[INITIATOR-NOTIFY-SUSPEND] %p\n", mono_thread_info_get_tid (info));
81 MONO_SEM_POST (&suspend_semaphore);
82 InterlockedIncrement (&suspend_posts);
86 mono_threads_notify_initiator_of_resume (MonoThreadInfo* info)
88 THREADS_SUSPEND_DEBUG ("[INITIATOR-NOTIFY-RESUME] %p\n", mono_thread_info_get_tid (info));
89 MONO_SEM_POST (&suspend_semaphore);
90 InterlockedIncrement (&resume_posts);
94 resume_async_suspended (MonoThreadInfo *info)
96 g_assert (mono_threads_core_begin_async_resume (info));
100 resume_self_suspended (MonoThreadInfo* info)
102 THREADS_SUSPEND_DEBUG ("**BEGIN self-resume %p\n", mono_thread_info_get_tid (info));
103 MONO_SEM_POST (&info->resume_semaphore);
107 mono_thread_info_wait_for_resume (MonoThreadInfo* info)
109 THREADS_SUSPEND_DEBUG ("**WAIT self-resume %p\n", mono_thread_info_get_tid (info));
110 MONO_SEM_WAIT_UNITERRUPTIBLE (&info->resume_semaphore);
114 resume_blocking_suspended (MonoThreadInfo* info)
116 THREADS_SUSPEND_DEBUG ("**BEGIN blocking-resume %p\n", mono_thread_info_get_tid (info));
117 MONO_SEM_POST (&info->resume_semaphore);
121 mono_threads_add_to_pending_operation_set (MonoThreadInfo* info)
123 THREADS_SUSPEND_DEBUG ("added %p to pending suspend\n", mono_thread_info_get_tid (info));
125 InterlockedIncrement (&pending_ops);
129 mono_threads_begin_global_suspend (void)
131 g_assert (pending_suspends == 0);
132 THREADS_SUSPEND_DEBUG ("------ BEGIN GLOBAL OP sp %d rp %d ap %d wd %d po %d\n", suspend_posts, resume_posts,
133 abort_posts, waits_done, pending_ops);
134 mono_threads_core_begin_global_suspend ();
138 mono_threads_end_global_suspend (void)
140 g_assert (pending_suspends == 0);
141 THREADS_SUSPEND_DEBUG ("------ END GLOBAL OP sp %d rp %d ap %d wd %d po %d\n", suspend_posts, resume_posts,
142 abort_posts, waits_done, pending_ops);
143 mono_threads_core_end_global_suspend ();
149 MonoThreadInfo *info;
150 MonoThreadInfo *cur = mono_thread_info_current ();
152 MOSTLY_ASYNC_SAFE_PRINTF ("STATE CUE CARD: (? means a positive number, usually 1 or 2, * means any number)\n");
153 MOSTLY_ASYNC_SAFE_PRINTF ("\t0x0\t- starting (GOOD, unless the thread is running managed code)\n");
154 MOSTLY_ASYNC_SAFE_PRINTF ("\t0x1\t- running (BAD, unless it's the gc thread)\n");
155 MOSTLY_ASYNC_SAFE_PRINTF ("\t0x2\t- detached (GOOD, unless the thread is running managed code)\n");
156 MOSTLY_ASYNC_SAFE_PRINTF ("\t0x?03\t- async suspended (GOOD)\n");
157 MOSTLY_ASYNC_SAFE_PRINTF ("\t0x?04\t- self suspended (GOOD)\n");
158 MOSTLY_ASYNC_SAFE_PRINTF ("\t0x?05\t- async suspend requested (BAD)\n");
159 MOSTLY_ASYNC_SAFE_PRINTF ("\t0x?06\t- self suspend requested (BAD)\n");
160 MOSTLY_ASYNC_SAFE_PRINTF ("\t0x*07\t- blocking (GOOD)\n");
161 MOSTLY_ASYNC_SAFE_PRINTF ("\t0x?08\t- blocking with pending suspend (GOOD)\n");
163 FOREACH_THREAD_SAFE (info) {
164 MOSTLY_ASYNC_SAFE_PRINTF ("--thread %p id %p [%p] state %x %s\n", info, (void *) mono_thread_info_get_tid (info), (void*)(size_t)info->native_handle, info->thread_state, info == cur ? "GC INITIATOR" : "" );
165 } END_FOREACH_THREAD_SAFE
169 mono_threads_wait_pending_operations (void)
172 int c = pending_suspends;
174 /* Wait threads to park */
175 if (pending_suspends) {
176 MonoStopwatch suspension_time;
177 mono_stopwatch_start (&suspension_time);
178 THREADS_SUSPEND_DEBUG ("[INITIATOR-WAIT-COUNT] %d\n", c);
179 for (i = 0; i < pending_suspends; ++i) {
180 THREADS_SUSPEND_DEBUG ("[INITIATOR-WAIT-WAITING]\n");
181 InterlockedIncrement (&waits_done);
182 if (!MONO_SEM_TIMEDWAIT (&suspend_semaphore, SLEEP_DURATION_BEFORE_ABORT))
184 mono_stopwatch_stop (&suspension_time);
188 MOSTLY_ASYNC_SAFE_PRINTF ("WAITING for %d threads, got %d suspended\n", (int)pending_suspends, i);
189 g_error ("suspend_thread suspend took %d ms, which is more than the allowed %d ms", (int)mono_stopwatch_elapsed_ms (&suspension_time), SLEEP_DURATION_BEFORE_ABORT);
191 mono_stopwatch_stop (&suspension_time);
192 THREADS_SUSPEND_DEBUG ("Suspending %d threads took %d ms.\n", (int)pending_suspends, (int)mono_stopwatch_elapsed_ms (&suspension_time));
196 pending_suspends = 0;
202 //Thread initialization code
204 static void mono_threads_unregister_current_thread (MonoThreadInfo *info);
207 mono_hazard_pointer_clear_all (MonoThreadHazardPointers *hp, int retain)
210 mono_hazard_pointer_clear (hp, 0);
212 mono_hazard_pointer_clear (hp, 1);
214 mono_hazard_pointer_clear (hp, 2);
218 If return non null Hazard Pointer 1 holds the return value.
221 mono_thread_info_lookup (MonoNativeThreadId id)
223 MonoThreadHazardPointers *hp = mono_hazard_pointer_get ();
225 if (!mono_lls_find (&thread_list, hp, (uintptr_t)id)) {
226 mono_hazard_pointer_clear_all (hp, -1);
230 mono_hazard_pointer_clear_all (hp, 1);
231 return (MonoThreadInfo *) mono_hazard_pointer_get_val (hp, 1);
235 mono_thread_info_insert (MonoThreadInfo *info)
237 MonoThreadHazardPointers *hp = mono_hazard_pointer_get ();
239 if (!mono_lls_insert (&thread_list, hp, (MonoLinkedListSetNode*)info)) {
240 mono_hazard_pointer_clear_all (hp, -1);
244 mono_hazard_pointer_clear_all (hp, -1);
249 mono_thread_info_remove (MonoThreadInfo *info)
251 MonoThreadHazardPointers *hp = mono_hazard_pointer_get ();
254 THREADS_DEBUG ("removing info %p\n", info);
255 res = mono_lls_remove (&thread_list, hp, (MonoLinkedListSetNode*)info);
256 mono_hazard_pointer_clear_all (hp, -1);
261 free_thread_info (gpointer mem)
263 MonoThreadInfo *info = (MonoThreadInfo *) mem;
265 MONO_SEM_DESTROY (&info->resume_semaphore);
266 mono_threads_platform_free (info);
272 mono_thread_info_register_small_id (void)
274 int small_id = mono_thread_small_id_alloc ();
275 #ifdef HAVE_KW_THREAD
276 tls_small_id = small_id;
278 mono_native_tls_set_value (small_id_key, GUINT_TO_POINTER (small_id + 1));
284 register_thread (MonoThreadInfo *info, gpointer baseptr)
287 guint8 *staddr = NULL;
288 int small_id = mono_thread_info_register_small_id ();
290 mono_thread_info_set_tid (info, mono_native_thread_id_get ());
291 info->small_id = small_id;
293 MONO_SEM_INIT (&info->resume_semaphore, 0);
295 /*set TLS early so SMR works */
296 mono_native_tls_set_value (thread_info_key, info);
298 THREADS_DEBUG ("registering info %p tid %p small id %x\n", info, mono_thread_info_get_tid (info), info->small_id);
300 if (threads_callbacks.thread_register) {
301 if (threads_callbacks.thread_register (info, baseptr) == NULL) {
302 // g_warning ("thread registation failed\n");
308 mono_thread_info_get_stack_bounds (&staddr, &stsize);
311 info->stack_start_limit = staddr;
312 info->stack_end = staddr + stsize;
314 mono_threads_platform_register (info);
317 Transition it before taking any locks or publishing itself to reduce the chance
318 of others witnessing a detached thread.
319 We can reasonably expect that until this thread gets published, no other thread will
320 try to manipulate it.
322 mono_threads_transition_attach (info);
323 mono_thread_info_suspend_lock ();
324 /*If this fail it means a given thread has been registered twice, which doesn't make sense. */
325 result = mono_thread_info_insert (info);
327 mono_thread_info_suspend_unlock ();
332 unregister_thread (void *arg)
334 MonoThreadInfo *info = (MonoThreadInfo *) arg;
335 int small_id = info->small_id;
338 THREADS_DEBUG ("unregistering info %p\n", info);
340 mono_native_tls_set_value (thread_exited_key, GUINT_TO_POINTER (1));
342 mono_threads_core_unregister (info);
345 * TLS destruction order is not reliable so small_id might be cleaned up
348 #ifndef HAVE_KW_THREAD
349 mono_native_tls_set_value (small_id_key, GUINT_TO_POINTER (info->small_id + 1));
353 First perform the callback that requires no locks.
354 This callback has the potential of taking other locks, so we do it before.
355 After it completes, the thread remains functional.
357 if (threads_callbacks.thread_detach)
358 threads_callbacks.thread_detach (info);
360 mono_thread_info_suspend_lock ();
363 Now perform the callback that must be done under locks.
364 This will render the thread useless and non-suspendable, so it must
365 be done while holding the suspend lock to give no other thread chance
368 if (threads_callbacks.thread_unregister)
369 threads_callbacks.thread_unregister (info);
370 mono_threads_unregister_current_thread (info);
371 mono_threads_transition_detach (info);
373 mono_thread_info_suspend_unlock ();
375 /*now it's safe to free the thread info.*/
376 mono_thread_hazardous_free_or_queue (info, free_thread_info, TRUE, FALSE);
377 mono_thread_small_id_free (small_id);
381 thread_exited_dtor (void *arg)
383 #if defined(__MACH__)
385 * Since we use pthread dtors to clean up thread data, if a thread
386 * is attached to the runtime by another pthread dtor after our dtor
387 * has ran, it will never be detached, leading to various problems
388 * since the thread ids etc. will be reused while they are still in
389 * the threads hashtables etc.
390 * Dtors are called in a loop until all user tls entries are 0,
391 * but the loop has a maximum count (4), so if we set the tls
392 * variable every time, it will remain set when system tls dtors
393 * are ran. This allows mono_thread_info_is_exiting () to detect
394 * whenever the thread is exiting, even if it is executed from a
395 * system tls dtor (i.e. obj-c dealloc methods).
397 mono_native_tls_set_value (thread_exited_key, GUINT_TO_POINTER (1));
402 * Removes the current thread from the thread list.
403 * This must be called from the thread unregister callback and nowhere else.
404 * The current thread must be passed as TLS might have already been cleaned up.
407 mono_threads_unregister_current_thread (MonoThreadInfo *info)
410 g_assert (mono_thread_info_get_tid (info) == mono_native_thread_id_get ());
411 result = mono_thread_info_remove (info);
416 mono_thread_info_current_unchecked (void)
418 return (MonoThreadInfo*)mono_native_tls_get_value (thread_info_key);
423 mono_thread_info_current (void)
425 MonoThreadInfo *info = (MonoThreadInfo*)mono_native_tls_get_value (thread_info_key);
429 info = mono_thread_info_lookup (mono_native_thread_id_get ()); /*info on HP1*/
432 We might be called during thread cleanup, but we cannot be called after cleanup as happened.
433 The way to distinguish between before, during and after cleanup is the following:
435 -If the TLS key is set, cleanup has not begun;
436 -If the TLS key is clean, but the thread remains registered, cleanup is in progress;
437 -If the thread is nowhere to be found, cleanup has finished.
439 We cannot function after cleanup since there's no way to ensure what will happen.
443 /*We're looking up the current thread which will not be freed until we finish running, so no need to keep it on a HP */
444 mono_hazard_pointer_clear (mono_hazard_pointer_get (), 1);
450 mono_thread_info_get_small_id (void)
452 #ifdef HAVE_KW_THREAD
455 gpointer val = mono_native_tls_get_value (small_id_key);
458 return GPOINTER_TO_INT (val) - 1;
463 mono_thread_info_list_head (void)
469 * mono_threads_attach_tools_thread
471 * Attach the current thread as a tool thread. DON'T USE THIS FUNCTION WITHOUT READING ALL DISCLAIMERS.
473 * A tools thread is a very special kind of thread that needs access to core runtime facilities but should
474 * not be counted as a regular thread for high order facilities such as executing managed code or accessing
477 * This is intended only to tools such as a profiler than needs to be able to use our lock-free support when
478 * doing things like resolving backtraces in their background processing thread.
481 mono_threads_attach_tools_thread (void)
484 MonoThreadInfo *info;
486 /* Must only be called once */
487 g_assert (!mono_native_tls_get_value (thread_info_key));
489 while (!mono_threads_inited) {
493 info = mono_thread_info_attach (&dummy);
496 info->tools_thread = TRUE;
500 mono_thread_info_attach (void *baseptr)
502 MonoThreadInfo *info;
503 if (!mono_threads_inited)
506 /* This can happen from DllMain(DLL_THREAD_ATTACH) on Windows, if a
507 * thread is created before an embedding API user initialized Mono. */
508 THREADS_DEBUG ("mono_thread_info_attach called before mono_threads_init\n");
511 g_assert (mono_threads_inited);
514 info = (MonoThreadInfo *) mono_native_tls_get_value (thread_info_key);
516 info = (MonoThreadInfo *) g_malloc0 (thread_info_size);
517 THREADS_DEBUG ("attaching %p\n", info);
518 if (!register_thread (info, baseptr))
520 } else if (threads_callbacks.thread_attach) {
521 threads_callbacks.thread_attach (info);
527 mono_thread_info_detach (void)
529 MonoThreadInfo *info;
530 if (!mono_threads_inited)
532 /* This can happen from DllMain(THREAD_DETACH) on Windows, if a thread
533 * is created before an embedding API user initialized Mono. */
534 THREADS_DEBUG ("mono_thread_info_detach called before mono_threads_init\n");
537 info = (MonoThreadInfo *) mono_native_tls_get_value (thread_info_key);
539 THREADS_DEBUG ("detaching %p\n", info);
540 unregister_thread (info);
541 mono_native_tls_set_value (thread_info_key, NULL);
546 * mono_thread_info_is_exiting:
548 * Return whenever the current thread is exiting, i.e. it is running pthread
552 mono_thread_info_is_exiting (void)
554 #if defined(__MACH__)
555 if (mono_native_tls_get_value (thread_exited_key) == GUINT_TO_POINTER (1))
562 mono_threads_init (MonoThreadInfoCallbacks *callbacks, size_t info_size)
565 threads_callbacks = *callbacks;
566 thread_info_size = info_size;
568 res = mono_native_tls_alloc (&thread_info_key, NULL);
569 res = mono_native_tls_alloc (&thread_exited_key, NULL);
571 res = mono_native_tls_alloc (&thread_info_key, (void *) unregister_thread);
572 res = mono_native_tls_alloc (&thread_exited_key, (void *) thread_exited_dtor);
576 #ifndef HAVE_KW_THREAD
577 res = mono_native_tls_alloc (&small_id_key, NULL);
581 unified_suspend_enabled = g_getenv ("MONO_ENABLE_UNIFIED_SUSPEND") != NULL || MONO_THREADS_PLATFORM_REQUIRES_UNIFIED_SUSPEND;
583 MONO_SEM_INIT (&global_suspend_semaphore, 1);
584 MONO_SEM_INIT (&suspend_semaphore, 0);
586 mono_lls_init (&thread_list, NULL);
587 mono_thread_smr_init ();
588 mono_threads_init_platform ();
590 #if defined(__MACH__)
591 mono_mach_init (thread_info_key);
594 mono_threads_inited = TRUE;
596 g_assert (sizeof (MonoNativeThreadId) <= sizeof (uintptr_t));
600 mono_threads_runtime_init (MonoThreadInfoRuntimeCallbacks *callbacks)
602 runtime_callbacks = *callbacks;
605 MonoThreadInfoRuntimeCallbacks *
606 mono_threads_get_runtime_callbacks (void)
608 return &runtime_callbacks;
612 The return value is only valid until a matching mono_thread_info_resume is called
614 static MonoThreadInfo*
615 mono_thread_info_suspend_sync (MonoNativeThreadId tid, gboolean interrupt_kernel, const char **error_condition)
617 MonoThreadHazardPointers *hp = mono_hazard_pointer_get ();
618 MonoThreadInfo *info = mono_thread_info_lookup (tid); /*info on HP1*/
620 *error_condition = "Thread not found";
624 switch (mono_threads_transition_request_async_suspension (info)) {
625 case AsyncSuspendAlreadySuspended:
626 mono_hazard_pointer_clear (hp, 1); //XXX this is questionable we got to clean the suspend/resume nonsense of critical sections
628 case AsyncSuspendWait:
629 mono_threads_add_to_pending_operation_set (info);
631 case AsyncSuspendInitSuspend:
632 if (!mono_threads_core_begin_async_suspend (info, interrupt_kernel)) {
633 mono_hazard_pointer_clear (hp, 1);
634 *error_condition = "Could not suspend thread";
639 //Wait for the pending suspend to finish
640 mono_threads_wait_pending_operations ();
642 if (!mono_threads_core_check_suspend_result (info)) {
644 mono_hazard_pointer_clear (hp, 1);
645 *error_condition = "Post suspend failed";
652 Signal that the current thread wants to be suspended.
653 This function can be called without holding the suspend lock held.
654 To finish suspending, call mono_suspend_check.
657 mono_thread_info_begin_self_suspend (void)
659 MonoThreadInfo *info = mono_thread_info_current_unchecked ();
663 THREADS_SUSPEND_DEBUG ("BEGIN SELF SUSPEND OF %p\n", info);
664 mono_threads_transition_request_self_suspension (info);
668 mono_thread_info_end_self_suspend (void)
670 MonoThreadInfo *info;
672 info = mono_thread_info_current ();
675 THREADS_SUSPEND_DEBUG ("FINISH SELF SUSPEND OF %p\n", info);
677 mono_threads_get_runtime_callbacks ()->thread_state_init (&info->thread_saved_state [SELF_SUSPEND_STATE_INDEX]);
679 /* commit the saved state and notify others if needed */
680 switch (mono_threads_transition_state_poll (info)) {
681 case SelfSuspendResumed:
683 case SelfSuspendWait:
684 mono_thread_info_wait_for_resume (info);
686 case SelfSuspendNotifyAndWait:
687 mono_threads_notify_initiator_of_suspend (info);
688 mono_thread_info_wait_for_resume (info);
689 mono_threads_notify_initiator_of_resume (info);
695 mono_thread_info_core_resume (MonoThreadInfo *info)
697 gboolean res = FALSE;
698 if (info->create_suspended) {
699 MonoNativeThreadId tid = mono_thread_info_get_tid (info);
700 /* Have to special case this, as the normal suspend/resume pair are racy, they don't work if he resume is received before the suspend */
701 info->create_suspended = FALSE;
702 mono_threads_core_resume_created (info, tid);
706 switch (mono_threads_transition_request_resume (info)) {
713 case ResumeInitSelfResume:
714 resume_self_suspended (info);
717 case ResumeInitAsyncResume:
718 resume_async_suspended (info);
721 case ResumeInitBlockingResume:
722 resume_blocking_suspended (info);
731 mono_thread_info_resume (MonoNativeThreadId tid)
733 gboolean result; /* don't initialize it so the compiler can catch unitilized paths. */
734 MonoThreadHazardPointers *hp = mono_hazard_pointer_get ();
735 MonoThreadInfo *info;
737 THREADS_SUSPEND_DEBUG ("RESUMING tid %p\n", (void*)tid);
739 mono_thread_info_suspend_lock ();
741 info = mono_thread_info_lookup (tid); /*info on HP1*/
747 result = mono_thread_info_core_resume (info);
749 //Wait for the pending resume to finish
750 mono_threads_wait_pending_operations ();
753 mono_thread_info_suspend_unlock ();
754 mono_hazard_pointer_clear (hp, 1);
759 mono_thread_info_begin_suspend (MonoThreadInfo *info, gboolean interrupt_kernel)
761 switch (mono_threads_transition_request_async_suspension (info)) {
762 case AsyncSuspendAlreadySuspended:
764 case AsyncSuspendWait:
765 mono_threads_add_to_pending_operation_set (info);
767 case AsyncSuspendInitSuspend:
768 return mono_threads_core_begin_async_suspend (info, interrupt_kernel);
770 g_assert_not_reached ();
775 mono_thread_info_begin_resume (MonoThreadInfo *info)
777 return mono_thread_info_core_resume (info);
781 FIXME fix cardtable WB to be out of line and check with the runtime if the target is not the
782 WB trampoline. Another option is to encode wb ranges in MonoJitInfo, but that is somewhat hard.
785 is_thread_in_critical_region (MonoThreadInfo *info)
789 gpointer stack_start;
790 MonoThreadUnwindState *state;
792 /* Are we inside a system critical region? */
793 if (info->inside_critical_region)
796 /* Are we inside a GC critical region? */
797 if (threads_callbacks.mono_thread_in_critical_region && threads_callbacks.mono_thread_in_critical_region (info)) {
801 /* The target thread might be shutting down and the domain might be null, which means no managed code left to run. */
802 state = mono_thread_info_get_suspend_state (info);
803 if (!state->unwind_data [MONO_UNWIND_DATA_DOMAIN])
806 stack_start = MONO_CONTEXT_GET_SP (&state->ctx);
807 /* altstack signal handler, sgen can't handle them, so we treat them as critical */
808 if (stack_start < info->stack_start_limit || stack_start >= info->stack_end)
811 ji = mono_jit_info_table_find (
812 (MonoDomain *) state->unwind_data [MONO_UNWIND_DATA_DOMAIN],
813 (char *) MONO_CONTEXT_GET_IP (&state->ctx));
818 method = mono_jit_info_get_method (ji);
820 return threads_callbacks.mono_method_is_critical (method);
824 mono_thread_info_in_critical_location (MonoThreadInfo *info)
826 return is_thread_in_critical_region (info);
829 static MonoThreadInfo*
830 suspend_sync_nolock (MonoNativeThreadId id, gboolean interrupt_kernel)
832 MonoThreadInfo *info = NULL;
833 int sleep_duration = 0;
835 const char *suspend_error = "Unknown error";
836 if (!(info = mono_thread_info_suspend_sync (id, interrupt_kernel, &suspend_error))) {
837 mono_hazard_pointer_clear (mono_hazard_pointer_get (), 1);
841 /*WARNING: We now are in interrupt context until we resume the thread. */
842 if (!is_thread_in_critical_region (info))
845 if (!mono_thread_info_core_resume (info)) {
846 mono_hazard_pointer_clear (mono_hazard_pointer_get (), 1);
849 THREADS_SUSPEND_DEBUG ("RESTARTED thread tid %p\n", (void*)id);
851 /* Wait for the pending resume to finish */
852 mono_threads_wait_pending_operations ();
854 if (!sleep_duration) {
862 g_usleep (sleep_duration);
864 sleep_duration += 10;
870 mono_thread_info_safe_suspend_and_run (MonoNativeThreadId id, gboolean interrupt_kernel, MonoSuspendThreadCallback callback, gpointer user_data)
873 MonoThreadInfo *info = NULL;
874 MonoThreadHazardPointers *hp = mono_hazard_pointer_get ();
876 THREADS_SUSPEND_DEBUG ("SUSPENDING tid %p\n", (void*)id);
877 /*FIXME: unify this with self-suspend*/
878 g_assert (id != mono_native_thread_id_get ());
880 /* This can block during stw */
881 mono_thread_info_suspend_lock ();
882 mono_threads_begin_global_suspend ();
884 info = suspend_sync_nolock (id, interrupt_kernel);
888 switch (result = callback (info, user_data)) {
889 case MonoResumeThread:
890 mono_hazard_pointer_set (hp, 1, info);
891 mono_thread_info_core_resume (info);
892 mono_threads_wait_pending_operations ();
897 g_error ("Invalid suspend_and_run callback return value %d", result);
901 mono_hazard_pointer_clear (hp, 1);
902 mono_threads_end_global_suspend ();
903 mono_thread_info_suspend_unlock ();
908 If we are trying to suspend a target that is on a critical region
909 and running a syscall we risk looping forever if @interrupt_kernel is FALSE.
910 So, be VERY carefull in calling this with @interrupt_kernel == FALSE.
912 Info is not put on a hazard pointer as a suspended thread cannot exit and be freed.
914 This function MUST be matched with mono_thread_info_finish_suspend or mono_thread_info_finish_suspend_and_resume
917 mono_thread_info_safe_suspend_sync (MonoNativeThreadId id, gboolean interrupt_kernel)
919 MonoThreadInfo *info = NULL;
921 THREADS_SUSPEND_DEBUG ("SUSPENDING tid %p\n", (void*)id);
922 /*FIXME: unify this with self-suspend*/
923 g_assert (id != mono_native_thread_id_get ());
925 mono_thread_info_suspend_lock ();
926 mono_threads_begin_global_suspend ();
928 info = suspend_sync_nolock (id, interrupt_kernel);
930 /* XXX this clears HP 1, so we restated it again */
931 // mono_atomic_store_release (&mono_thread_info_current ()->inside_critical_region, TRUE);
932 mono_threads_end_global_suspend ();
933 mono_thread_info_suspend_unlock ();
939 Inject an assynchronous call into the target thread. The target thread must be suspended and
940 only a single async call can be setup for a given suspend cycle.
941 This async call must cause stack unwinding as the current implementation doesn't save enough state
942 to resume execution of the top-of-stack function. It's an acceptable limitation since this is
943 currently used only to deliver exceptions.
946 mono_thread_info_setup_async_call (MonoThreadInfo *info, void (*target_func)(void*), void *user_data)
948 /* An async call can only be setup on an async suspended thread */
949 g_assert (mono_thread_info_run_state (info) == STATE_ASYNC_SUSPENDED);
950 /*FIXME this is a bad assert, we probably should do proper locking and fail if one is already set*/
951 g_assert (!info->async_target);
952 info->async_target = target_func;
953 /* This is not GC tracked */
954 info->user_data = user_data;
958 The suspend lock is held during any suspend in progress.
959 A GC that has safepoints must take this lock as part of its
960 STW to make sure no unsafe pending suspend is in progress.
963 mono_thread_info_suspend_lock (void)
966 MONO_SEM_WAIT_UNITERRUPTIBLE (&global_suspend_semaphore);
967 MONO_FINISH_TRY_BLOCKING;
971 mono_thread_info_suspend_unlock (void)
973 MONO_SEM_POST (&global_suspend_semaphore);
977 * This is a very specific function whose only purpose is to
978 * break a given thread from socket syscalls.
980 * This only exists because linux won't fail a call to connect
981 * if the underlying is closed.
983 * TODO We should cleanup and unify this with the other syscall abort
987 mono_thread_info_abort_socket_syscall_for_close (MonoNativeThreadId tid)
989 MonoThreadHazardPointers *hp;
990 MonoThreadInfo *info;
992 if (tid == mono_native_thread_id_get () || !mono_threads_core_needs_abort_syscall ())
995 hp = mono_hazard_pointer_get ();
996 info = mono_thread_info_lookup (tid); /*info on HP1*/
1000 if (mono_thread_info_run_state (info) > STATE_RUNNING) {
1001 mono_hazard_pointer_clear (hp, 1);
1005 mono_thread_info_suspend_lock ();
1006 mono_threads_begin_global_suspend ();
1008 mono_threads_core_abort_syscall (info);
1009 mono_threads_wait_pending_operations ();
1011 mono_hazard_pointer_clear (hp, 1);
1013 mono_threads_end_global_suspend ();
1014 mono_thread_info_suspend_unlock ();
1018 mono_thread_info_unified_management_enabled (void)
1020 return unified_suspend_enabled;
1024 * mono_thread_info_set_is_async_context:
1026 * Set whenever the current thread is in an async context. Some runtime functions might behave
1027 * differently while in an async context in order to be async safe.
1030 mono_thread_info_set_is_async_context (gboolean async_context)
1032 MonoThreadInfo *info = mono_thread_info_current ();
1035 info->is_async_context = async_context;
1039 mono_thread_info_is_async_context (void)
1041 MonoThreadInfo *info = mono_thread_info_current ();
1044 return info->is_async_context;
1050 * mono_threads_create_thread:
1052 * Create a new thread executing START with argument ARG. Store its id into OUT_TID.
1053 * Returns: a windows or io-layer handle for the thread.
1056 mono_threads_create_thread (LPTHREAD_START_ROUTINE start, gpointer arg, guint32 stack_size, guint32 creation_flags, MonoNativeThreadId *out_tid)
1058 return mono_threads_core_create_thread (start, arg, stack_size, creation_flags, out_tid);
1062 * mono_thread_info_get_stack_bounds:
1064 * Return the address and size of the current threads stack. Return NULL as the
1065 * stack address if the stack address cannot be determined.
1068 mono_thread_info_get_stack_bounds (guint8 **staddr, size_t *stsize)
1070 guint8 *current = (guint8 *)&stsize;
1071 mono_threads_core_get_stack_bounds (staddr, stsize);
1075 /* Sanity check the result */
1076 g_assert ((current > *staddr) && (current < *staddr + *stsize));
1078 /* When running under emacs, sometimes staddr is not aligned to a page size */
1079 *staddr = (guint8*)((gssize)*staddr & ~(mono_pagesize () - 1));
1083 mono_thread_info_yield (void)
1085 return mono_threads_core_yield ();
1089 mono_thread_info_tls_get (THREAD_INFO_TYPE *info, MonoTlsKey key)
1091 return ((MonoThreadInfo*)info)->tls [key];
1095 * mono_threads_info_tls_set:
1097 * Set the TLS key to VALUE in the info structure. This can be used to obtain
1098 * values of TLS variables for threads other than the current thread.
1099 * This should only be used for infrequently changing TLS variables, and it should
1100 * be paired with setting the real TLS variable since this provides no GC tracking.
1103 mono_thread_info_tls_set (THREAD_INFO_TYPE *info, MonoTlsKey key, gpointer value)
1105 ((MonoThreadInfo*)info)->tls [key] = value;
1109 * mono_thread_info_exit:
1111 * Exit the current thread.
1112 * This function doesn't return.
1115 mono_thread_info_exit (void)
1117 mono_threads_core_exit (0);
1121 * mono_thread_info_open_handle:
1123 * Return a io-layer/win32 handle for the current thread.
1124 * The handle need to be closed by calling CloseHandle () when it is no
1128 mono_thread_info_open_handle (void)
1130 return mono_threads_core_open_handle ();
1134 * mono_threads_open_thread_handle:
1136 * Return a io-layer/win32 handle for the thread identified by HANDLE/TID.
1137 * The handle need to be closed by calling CloseHandle () when it is no
1141 mono_threads_open_thread_handle (HANDLE handle, MonoNativeThreadId tid)
1143 return mono_threads_core_open_thread_handle (handle, tid);
1147 mono_thread_info_set_name (MonoNativeThreadId tid, const char *name)
1149 mono_threads_core_set_name (tid, name);
1152 #define INTERRUPT_STATE ((MonoThreadInfoInterruptToken*) (size_t) -1)
1154 struct _MonoThreadInfoInterruptToken {
1155 void (*callback) (gpointer data);
1160 * mono_thread_info_install_interrupt: install an interruption token for the current thread.
1162 * - @callback: must be able to be called from another thread and always cancel the wait
1163 * - @data: passed to the callback
1164 * - @interrupted: will be set to TRUE if a token is already installed, FALSE otherwise
1165 * if set to TRUE, it must mean that the thread is in interrupted state
1168 mono_thread_info_install_interrupt (void (*callback) (gpointer data), gpointer data, gboolean *interrupted)
1170 MonoThreadInfo *info;
1171 MonoThreadInfoInterruptToken *previous_token, *token;
1173 g_assert (callback);
1175 g_assert (interrupted);
1176 *interrupted = FALSE;
1178 info = mono_thread_info_current ();
1181 /* The memory of this token can be freed at 2 places:
1182 * - if the token is not interrupted: it will be freed in uninstall, as info->interrupt_token has not been replaced
1183 * by the INTERRUPT_STATE flag value, and it still contains the pointer to the memory location
1184 * - if the token is interrupted: it will be freed in finish, as the token is now owned by the prepare/finish
1185 * functions, and info->interrupt_token does not contains a pointer to the memory anymore */
1186 token = g_new0 (MonoThreadInfoInterruptToken, 1);
1187 token->callback = callback;
1190 previous_token = InterlockedCompareExchangePointer ((gpointer*) &info->interrupt_token, token, NULL);
1192 if (previous_token) {
1193 if (previous_token != INTERRUPT_STATE)
1194 g_error ("mono_thread_info_install_interrupt: previous_token should be INTERRUPT_STATE (%p), but it was %p", INTERRUPT_STATE, previous_token);
1198 *interrupted = TRUE;
1201 THREADS_INTERRUPT_DEBUG ("interrupt install tid %p token %p previous_token %p interrupted %s\n",
1202 mono_thread_info_get_tid (info), token, previous_token, *interrupted ? "TRUE" : "FALSE");
1206 mono_thread_info_uninstall_interrupt (gboolean *interrupted)
1208 MonoThreadInfo *info;
1209 MonoThreadInfoInterruptToken *previous_token;
1211 g_assert (interrupted);
1212 *interrupted = FALSE;
1214 info = mono_thread_info_current ();
1217 previous_token = InterlockedExchangePointer ((gpointer*) &info->interrupt_token, NULL);
1219 /* only the installer can uninstall the token */
1220 g_assert (previous_token);
1222 if (previous_token == INTERRUPT_STATE) {
1223 /* if it is interrupted, then it is going to be freed in finish interrupt */
1224 *interrupted = TRUE;
1226 g_free (previous_token);
1229 THREADS_INTERRUPT_DEBUG ("interrupt uninstall tid %p previous_token %p interrupted %s\n",
1230 mono_thread_info_get_tid (info), previous_token, *interrupted ? "TRUE" : "FALSE");
1233 static MonoThreadInfoInterruptToken*
1234 set_interrupt_state (MonoThreadInfo *info)
1236 MonoThreadInfoInterruptToken *token, *previous_token;
1240 /* Atomically obtain the token the thread is
1241 * waiting on, and change it to a flag value. */
1244 previous_token = info->interrupt_token;
1246 /* Already interrupted */
1247 if (previous_token == INTERRUPT_STATE) {
1252 token = previous_token;
1253 } while (InterlockedCompareExchangePointer ((gpointer*) &info->interrupt_token, INTERRUPT_STATE, previous_token) != previous_token);
1259 * mono_thread_info_prepare_interrupt:
1261 * The state of the thread info interrupt token is set to 'interrupted' which means that :
1262 * - if the thread calls one of the WaitFor functions, the function will return with
1263 * WAIT_IO_COMPLETION instead of waiting
1264 * - if the thread was waiting when this function was called, the wait will be broken
1266 * It is possible that the wait functions return WAIT_IO_COMPLETION, but the target thread
1267 * didn't receive the interrupt signal yet, in this case it should call the wait function
1268 * again. This essentially means that the target thread will busy wait until it is ready to
1269 * process the interruption.
1271 MonoThreadInfoInterruptToken*
1272 mono_thread_info_prepare_interrupt (MonoThreadInfo *info)
1274 MonoThreadInfoInterruptToken *token;
1276 token = set_interrupt_state (info);
1278 THREADS_INTERRUPT_DEBUG ("interrupt prepare tid %p token %p\n",
1279 mono_thread_info_get_tid (info), token);
1285 mono_thread_info_finish_interrupt (MonoThreadInfoInterruptToken *token)
1287 THREADS_INTERRUPT_DEBUG ("interrupt finish token %p\n", token);
1292 g_assert (token->callback);
1294 token->callback (token->data);
1300 mono_thread_info_self_interrupt (void)
1302 MonoThreadInfo *info;
1303 MonoThreadInfoInterruptToken *token;
1305 info = mono_thread_info_current ();
1308 token = set_interrupt_state (info);
1311 THREADS_INTERRUPT_DEBUG ("interrupt self tid %p\n",
1312 mono_thread_info_get_tid (info));
1315 /* Clear the interrupted flag of the current thread, set with
1316 * mono_thread_info_self_interrupt, so it can wait again */
1318 mono_thread_info_clear_self_interrupt ()
1320 MonoThreadInfo *info;
1321 MonoThreadInfoInterruptToken *previous_token;
1323 info = mono_thread_info_current ();
1326 previous_token = InterlockedCompareExchangePointer ((gpointer*) &info->interrupt_token, NULL, INTERRUPT_STATE);
1327 g_assert (previous_token == NULL || previous_token == INTERRUPT_STATE);
1329 THREADS_INTERRUPT_DEBUG ("interrupt clear self tid %p previous_token %p\n", mono_thread_info_get_tid (info), previous_token);
1333 mono_thread_info_is_interrupt_state (MonoThreadInfo *info)
1336 return InterlockedReadPointer ((gpointer*) &info->interrupt_token) == INTERRUPT_STATE;
1340 mono_thread_info_describe_interrupt_token (MonoThreadInfo *info, GString *text)
1344 if (!InterlockedReadPointer ((gpointer*) &info->interrupt_token))
1345 g_string_append_printf (text, "not waiting");
1346 else if (InterlockedReadPointer ((gpointer*) &info->interrupt_token) == INTERRUPT_STATE)
1347 g_string_append_printf (text, "interrupted state");
1349 g_string_append_printf (text, "waiting");
1352 /* info must be self or be held in a hazard pointer. */
1354 mono_threads_add_async_job (MonoThreadInfo *info, MonoAsyncJob job)
1356 MonoAsyncJob old_job;
1358 old_job = (MonoAsyncJob) info->service_requests;
1361 } while (InterlockedCompareExchange (&info->service_requests, old_job | job, old_job) != old_job);
1366 mono_threads_consume_async_jobs (void)
1368 MonoThreadInfo *info = (MonoThreadInfo*)mono_native_tls_get_value (thread_info_key);
1371 return (MonoAsyncJob) 0;
1373 return (MonoAsyncJob) InterlockedExchange (&info->service_requests, 0);