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)\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 ("\t0x07\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);
361 Since the thread info lock is taken from within blocking sections, we can't check from there, so it must be done here.
362 This ensures that we won't lose any suspend requests as a suspend initiator must hold the lock.
363 Once we're holding the suspend lock, no threads can suspend us and once we unregister, no thread can find us.
365 MONO_PREPARE_BLOCKING
366 mono_thread_info_suspend_lock ();
370 Now perform the callback that must be done under locks.
371 This will render the thread useless and non-suspendable, so it must
372 be done while holding the suspend lock to give no other thread chance
375 if (threads_callbacks.thread_unregister)
376 threads_callbacks.thread_unregister (info);
377 mono_threads_unregister_current_thread (info);
378 mono_threads_transition_detach (info);
380 mono_thread_info_suspend_unlock ();
382 /*now it's safe to free the thread info.*/
383 mono_thread_hazardous_free_or_queue (info, free_thread_info, TRUE, FALSE);
384 mono_thread_small_id_free (small_id);
388 thread_exited_dtor (void *arg)
390 #if defined(__MACH__)
392 * Since we use pthread dtors to clean up thread data, if a thread
393 * is attached to the runtime by another pthread dtor after our dtor
394 * has ran, it will never be detached, leading to various problems
395 * since the thread ids etc. will be reused while they are still in
396 * the threads hashtables etc.
397 * Dtors are called in a loop until all user tls entries are 0,
398 * but the loop has a maximum count (4), so if we set the tls
399 * variable every time, it will remain set when system tls dtors
400 * are ran. This allows mono_thread_info_is_exiting () to detect
401 * whenever the thread is exiting, even if it is executed from a
402 * system tls dtor (i.e. obj-c dealloc methods).
404 mono_native_tls_set_value (thread_exited_key, GUINT_TO_POINTER (1));
409 * Removes the current thread from the thread list.
410 * This must be called from the thread unregister callback and nowhere else.
411 * The current thread must be passed as TLS might have already been cleaned up.
414 mono_threads_unregister_current_thread (MonoThreadInfo *info)
417 g_assert (mono_thread_info_get_tid (info) == mono_native_thread_id_get ());
418 result = mono_thread_info_remove (info);
423 mono_thread_info_current_unchecked (void)
425 return (MonoThreadInfo*)mono_native_tls_get_value (thread_info_key);
430 mono_thread_info_current (void)
432 MonoThreadInfo *info = (MonoThreadInfo*)mono_native_tls_get_value (thread_info_key);
436 info = mono_thread_info_lookup (mono_native_thread_id_get ()); /*info on HP1*/
439 We might be called during thread cleanup, but we cannot be called after cleanup as happened.
440 The way to distinguish between before, during and after cleanup is the following:
442 -If the TLS key is set, cleanup has not begun;
443 -If the TLS key is clean, but the thread remains registered, cleanup is in progress;
444 -If the thread is nowhere to be found, cleanup has finished.
446 We cannot function after cleanup since there's no way to ensure what will happen.
450 /*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 */
451 mono_hazard_pointer_clear (mono_hazard_pointer_get (), 1);
457 mono_thread_info_get_small_id (void)
459 #ifdef HAVE_KW_THREAD
462 gpointer val = mono_native_tls_get_value (small_id_key);
465 return GPOINTER_TO_INT (val) - 1;
470 mono_thread_info_list_head (void)
476 * mono_threads_attach_tools_thread
478 * Attach the current thread as a tool thread. DON'T USE THIS FUNCTION WITHOUT READING ALL DISCLAIMERS.
480 * A tools thread is a very special kind of thread that needs access to core runtime facilities but should
481 * not be counted as a regular thread for high order facilities such as executing managed code or accessing
484 * This is intended only to tools such as a profiler than needs to be able to use our lock-free support when
485 * doing things like resolving backtraces in their background processing thread.
488 mono_threads_attach_tools_thread (void)
491 MonoThreadInfo *info;
493 /* Must only be called once */
494 g_assert (!mono_native_tls_get_value (thread_info_key));
496 while (!mono_threads_inited) {
500 info = mono_thread_info_attach (&dummy);
503 info->tools_thread = TRUE;
507 mono_thread_info_attach (void *baseptr)
509 MonoThreadInfo *info;
510 if (!mono_threads_inited)
513 /* This can happen from DllMain(DLL_THREAD_ATTACH) on Windows, if a
514 * thread is created before an embedding API user initialized Mono. */
515 THREADS_DEBUG ("mono_thread_info_attach called before mono_threads_init\n");
518 g_assert (mono_threads_inited);
521 info = (MonoThreadInfo *) mono_native_tls_get_value (thread_info_key);
523 info = (MonoThreadInfo *) g_malloc0 (thread_info_size);
524 THREADS_DEBUG ("attaching %p\n", info);
525 if (!register_thread (info, baseptr))
527 } else if (threads_callbacks.thread_attach) {
528 threads_callbacks.thread_attach (info);
534 mono_thread_info_detach (void)
536 MonoThreadInfo *info;
537 if (!mono_threads_inited)
539 /* This can happen from DllMain(THREAD_DETACH) on Windows, if a thread
540 * is created before an embedding API user initialized Mono. */
541 THREADS_DEBUG ("mono_thread_info_detach called before mono_threads_init\n");
544 info = (MonoThreadInfo *) mono_native_tls_get_value (thread_info_key);
546 THREADS_DEBUG ("detaching %p\n", info);
547 unregister_thread (info);
548 mono_native_tls_set_value (thread_info_key, NULL);
553 * mono_thread_info_is_exiting:
555 * Return whenever the current thread is exiting, i.e. it is running pthread
559 mono_thread_info_is_exiting (void)
561 #if defined(__MACH__)
562 if (mono_native_tls_get_value (thread_exited_key) == GUINT_TO_POINTER (1))
569 mono_threads_init (MonoThreadInfoCallbacks *callbacks, size_t info_size)
572 threads_callbacks = *callbacks;
573 thread_info_size = info_size;
575 res = mono_native_tls_alloc (&thread_info_key, NULL);
576 res = mono_native_tls_alloc (&thread_exited_key, NULL);
578 res = mono_native_tls_alloc (&thread_info_key, (void *) unregister_thread);
579 res = mono_native_tls_alloc (&thread_exited_key, (void *) thread_exited_dtor);
583 #ifndef HAVE_KW_THREAD
584 res = mono_native_tls_alloc (&small_id_key, NULL);
588 unified_suspend_enabled = g_getenv ("MONO_ENABLE_UNIFIED_SUSPEND") != NULL || MONO_THREADS_PLATFORM_REQUIRES_UNIFIED_SUSPEND;
590 MONO_SEM_INIT (&global_suspend_semaphore, 1);
591 MONO_SEM_INIT (&suspend_semaphore, 0);
593 mono_lls_init (&thread_list, NULL);
594 mono_thread_smr_init ();
595 mono_threads_init_platform ();
597 #if defined(__MACH__)
598 mono_mach_init (thread_info_key);
601 mono_threads_inited = TRUE;
603 g_assert (sizeof (MonoNativeThreadId) <= sizeof (uintptr_t));
607 mono_threads_runtime_init (MonoThreadInfoRuntimeCallbacks *callbacks)
609 runtime_callbacks = *callbacks;
612 MonoThreadInfoCallbacks *
613 mono_threads_get_callbacks (void)
615 return &threads_callbacks;
618 MonoThreadInfoRuntimeCallbacks *
619 mono_threads_get_runtime_callbacks (void)
621 return &runtime_callbacks;
625 The return value is only valid until a matching mono_thread_info_resume is called
627 static MonoThreadInfo*
628 mono_thread_info_suspend_sync (MonoNativeThreadId tid, gboolean interrupt_kernel, const char **error_condition)
630 MonoThreadHazardPointers *hp = mono_hazard_pointer_get ();
631 MonoThreadInfo *info = mono_thread_info_lookup (tid); /*info on HP1*/
633 *error_condition = "Thread not found";
637 switch (mono_threads_transition_request_async_suspension (info)) {
638 case AsyncSuspendAlreadySuspended:
639 mono_hazard_pointer_clear (hp, 1); //XXX this is questionable we got to clean the suspend/resume nonsense of critical sections
641 case AsyncSuspendWait:
642 mono_threads_add_to_pending_operation_set (info);
644 case AsyncSuspendInitSuspend:
645 if (!mono_threads_core_begin_async_suspend (info, interrupt_kernel)) {
646 mono_hazard_pointer_clear (hp, 1);
647 *error_condition = "Could not suspend thread";
652 //Wait for the pending suspend to finish
653 mono_threads_wait_pending_operations ();
655 if (!mono_threads_core_check_suspend_result (info)) {
657 mono_hazard_pointer_clear (hp, 1);
658 *error_condition = "Post suspend failed";
665 Signal that the current thread wants to be suspended.
666 This function can be called without holding the suspend lock held.
667 To finish suspending, call mono_suspend_check.
670 mono_thread_info_begin_self_suspend (void)
672 MonoThreadInfo *info = mono_thread_info_current_unchecked ();
676 THREADS_SUSPEND_DEBUG ("BEGIN SELF SUSPEND OF %p\n", info);
677 mono_threads_transition_request_self_suspension (info);
681 mono_thread_info_end_self_suspend (void)
683 MonoThreadInfo *info;
685 info = mono_thread_info_current ();
688 THREADS_SUSPEND_DEBUG ("FINISH SELF SUSPEND OF %p\n", info);
690 g_assert (mono_threads_get_runtime_callbacks ()->thread_state_init_from_sigctx (&info->thread_saved_state [SELF_SUSPEND_STATE_INDEX], NULL));
692 /* commit the saved state and notify others if needed */
693 switch (mono_threads_transition_state_poll (info)) {
694 case SelfSuspendResumed:
696 case SelfSuspendWait:
697 mono_thread_info_wait_for_resume (info);
699 case SelfSuspendNotifyAndWait:
700 mono_threads_notify_initiator_of_suspend (info);
701 mono_thread_info_wait_for_resume (info);
702 mono_threads_notify_initiator_of_resume (info);
708 mono_thread_info_core_resume (MonoThreadInfo *info)
710 gboolean res = FALSE;
711 if (info->create_suspended) {
712 MonoNativeThreadId tid = mono_thread_info_get_tid (info);
713 /* 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 */
714 info->create_suspended = FALSE;
715 mono_threads_core_resume_created (info, tid);
719 switch (mono_threads_transition_request_resume (info)) {
726 case ResumeInitSelfResume:
727 resume_self_suspended (info);
730 case ResumeInitAsyncResume:
731 resume_async_suspended (info);
734 case ResumeInitBlockingResume:
735 resume_blocking_suspended (info);
744 mono_thread_info_resume (MonoNativeThreadId tid)
746 gboolean result; /* don't initialize it so the compiler can catch unitilized paths. */
747 MonoThreadHazardPointers *hp = mono_hazard_pointer_get ();
748 MonoThreadInfo *info;
750 THREADS_SUSPEND_DEBUG ("RESUMING tid %p\n", (void*)tid);
752 mono_thread_info_suspend_lock ();
754 info = mono_thread_info_lookup (tid); /*info on HP1*/
760 result = mono_thread_info_core_resume (info);
762 //Wait for the pending resume to finish
763 mono_threads_wait_pending_operations ();
766 mono_thread_info_suspend_unlock ();
767 mono_hazard_pointer_clear (hp, 1);
772 mono_thread_info_begin_suspend (MonoThreadInfo *info, gboolean interrupt_kernel)
774 switch (mono_threads_transition_request_async_suspension (info)) {
775 case AsyncSuspendAlreadySuspended:
777 case AsyncSuspendWait:
778 mono_threads_add_to_pending_operation_set (info);
780 case AsyncSuspendInitSuspend:
781 return mono_threads_core_begin_async_suspend (info, interrupt_kernel);
783 g_assert_not_reached ();
788 mono_thread_info_begin_resume (MonoThreadInfo *info)
790 return mono_thread_info_core_resume (info);
794 FIXME fix cardtable WB to be out of line and check with the runtime if the target is not the
795 WB trampoline. Another option is to encode wb ranges in MonoJitInfo, but that is somewhat hard.
798 is_thread_in_critical_region (MonoThreadInfo *info)
802 gpointer stack_start;
803 MonoThreadUnwindState *state;
805 /* Are we inside a system critical region? */
806 if (info->inside_critical_region)
809 if (threads_callbacks.mono_thread_in_critical_region && threads_callbacks.mono_thread_in_critical_region (info)) {
813 /* Are we inside a GC critical region? */
814 if (threads_callbacks.mono_thread_in_critical_region && threads_callbacks.mono_thread_in_critical_region (info)) {
818 /* The target thread might be shutting down and the domain might be null, which means no managed code left to run. */
819 state = mono_thread_info_get_suspend_state (info);
820 if (!state->unwind_data [MONO_UNWIND_DATA_DOMAIN])
823 stack_start = MONO_CONTEXT_GET_SP (&state->ctx);
824 /* altstack signal handler, sgen can't handle them, so we treat them as critical */
825 if (stack_start < info->stack_start_limit || stack_start >= info->stack_end)
828 ji = mono_jit_info_table_find (
829 (MonoDomain *) state->unwind_data [MONO_UNWIND_DATA_DOMAIN],
830 (char *) MONO_CONTEXT_GET_IP (&state->ctx));
835 method = mono_jit_info_get_method (ji);
837 return threads_callbacks.mono_method_is_critical (method);
841 mono_thread_info_in_critical_location (MonoThreadInfo *info)
843 return is_thread_in_critical_region (info);
846 static MonoThreadInfo*
847 suspend_sync_nolock (MonoNativeThreadId id, gboolean interrupt_kernel)
849 MonoThreadInfo *info = NULL;
850 int sleep_duration = 0;
852 const char *suspend_error = "Unknown error";
853 if (!(info = mono_thread_info_suspend_sync (id, interrupt_kernel, &suspend_error))) {
854 mono_hazard_pointer_clear (mono_hazard_pointer_get (), 1);
858 /*WARNING: We now are in interrupt context until we resume the thread. */
859 if (!is_thread_in_critical_region (info))
862 if (!mono_thread_info_core_resume (info)) {
863 mono_hazard_pointer_clear (mono_hazard_pointer_get (), 1);
866 THREADS_SUSPEND_DEBUG ("RESTARTED thread tid %p\n", (void*)id);
868 /* Wait for the pending resume to finish */
869 mono_threads_wait_pending_operations ();
871 if (!sleep_duration) {
879 g_usleep (sleep_duration);
881 sleep_duration += 10;
887 mono_thread_info_safe_suspend_and_run (MonoNativeThreadId id, gboolean interrupt_kernel, MonoSuspendThreadCallback callback, gpointer user_data)
890 MonoThreadInfo *info = NULL;
891 MonoThreadHazardPointers *hp = mono_hazard_pointer_get ();
893 THREADS_SUSPEND_DEBUG ("SUSPENDING tid %p\n", (void*)id);
894 /*FIXME: unify this with self-suspend*/
895 g_assert (id != mono_native_thread_id_get ());
897 mono_thread_info_suspend_lock ();
898 mono_threads_begin_global_suspend ();
900 info = suspend_sync_nolock (id, interrupt_kernel);
904 switch (result = callback (info, user_data)) {
905 case MonoResumeThread:
906 mono_hazard_pointer_set (hp, 1, info);
907 mono_thread_info_core_resume (info);
908 mono_threads_wait_pending_operations ();
913 g_error ("Invalid suspend_and_run callback return value %d", result);
917 mono_hazard_pointer_clear (hp, 1);
918 mono_threads_end_global_suspend ();
919 mono_thread_info_suspend_unlock ();
924 If we are trying to suspend a target that is on a critical region
925 and running a syscall we risk looping forever if @interrupt_kernel is FALSE.
926 So, be VERY carefull in calling this with @interrupt_kernel == FALSE.
928 Info is not put on a hazard pointer as a suspended thread cannot exit and be freed.
930 This function MUST be matched with mono_thread_info_finish_suspend or mono_thread_info_finish_suspend_and_resume
933 mono_thread_info_safe_suspend_sync (MonoNativeThreadId id, gboolean interrupt_kernel)
935 MonoThreadInfo *info = NULL;
937 THREADS_SUSPEND_DEBUG ("SUSPENDING tid %p\n", (void*)id);
938 /*FIXME: unify this with self-suspend*/
939 g_assert (id != mono_native_thread_id_get ());
941 mono_thread_info_suspend_lock ();
942 mono_threads_begin_global_suspend ();
944 info = suspend_sync_nolock (id, interrupt_kernel);
946 /* XXX this clears HP 1, so we restated it again */
947 // mono_atomic_store_release (&mono_thread_info_current ()->inside_critical_region, TRUE);
948 mono_threads_end_global_suspend ();
949 mono_thread_info_suspend_unlock ();
955 Inject an assynchronous call into the target thread. The target thread must be suspended and
956 only a single async call can be setup for a given suspend cycle.
957 This async call must cause stack unwinding as the current implementation doesn't save enough state
958 to resume execution of the top-of-stack function. It's an acceptable limitation since this is
959 currently used only to deliver exceptions.
962 mono_thread_info_setup_async_call (MonoThreadInfo *info, void (*target_func)(void*), void *user_data)
964 /* An async call can only be setup on an async suspended thread */
965 g_assert (mono_thread_info_run_state (info) == STATE_ASYNC_SUSPENDED);
966 /*FIXME this is a bad assert, we probably should do proper locking and fail if one is already set*/
967 g_assert (!info->async_target);
968 info->async_target = target_func;
969 /* This is not GC tracked */
970 info->user_data = user_data;
974 The suspend lock is held during any suspend in progress.
975 A GC that has safepoints must take this lock as part of its
976 STW to make sure no unsafe pending suspend is in progress.
979 mono_thread_info_suspend_lock (void)
981 MONO_SEM_WAIT_UNITERRUPTIBLE (&global_suspend_semaphore);
985 mono_thread_info_suspend_unlock (void)
987 MONO_SEM_POST (&global_suspend_semaphore);
991 * This is a very specific function whose only purpose is to
992 * break a given thread from socket syscalls.
994 * This only exists because linux won't fail a call to connect
995 * if the underlying is closed.
997 * TODO We should cleanup and unify this with the other syscall abort
1001 mono_thread_info_abort_socket_syscall_for_close (MonoNativeThreadId tid)
1003 MonoThreadHazardPointers *hp;
1004 MonoThreadInfo *info;
1006 if (tid == mono_native_thread_id_get () || !mono_threads_core_needs_abort_syscall ())
1009 hp = mono_hazard_pointer_get ();
1010 info = mono_thread_info_lookup (tid); /*info on HP1*/
1014 if (mono_thread_info_run_state (info) > STATE_RUNNING) {
1015 mono_hazard_pointer_clear (hp, 1);
1019 mono_thread_info_suspend_lock ();
1020 mono_threads_begin_global_suspend ();
1022 mono_threads_core_abort_syscall (info);
1023 mono_threads_wait_pending_operations ();
1025 mono_hazard_pointer_clear (hp, 1);
1027 mono_threads_end_global_suspend ();
1028 mono_thread_info_suspend_unlock ();
1032 mono_thread_info_unified_management_enabled (void)
1034 return unified_suspend_enabled;
1038 * mono_thread_info_set_is_async_context:
1040 * Set whenever the current thread is in an async context. Some runtime functions might behave
1041 * differently while in an async context in order to be async safe.
1044 mono_thread_info_set_is_async_context (gboolean async_context)
1046 MonoThreadInfo *info = mono_thread_info_current ();
1049 info->is_async_context = async_context;
1053 mono_thread_info_is_async_context (void)
1055 MonoThreadInfo *info = mono_thread_info_current ();
1058 return info->is_async_context;
1064 * mono_threads_create_thread:
1066 * Create a new thread executing START with argument ARG. Store its id into OUT_TID.
1067 * Returns: a windows or io-layer handle for the thread.
1070 mono_threads_create_thread (LPTHREAD_START_ROUTINE start, gpointer arg, guint32 stack_size, guint32 creation_flags, MonoNativeThreadId *out_tid)
1072 return mono_threads_core_create_thread (start, arg, stack_size, creation_flags, out_tid);
1076 * mono_thread_info_get_stack_bounds:
1078 * Return the address and size of the current threads stack. Return NULL as the
1079 * stack address if the stack address cannot be determined.
1082 mono_thread_info_get_stack_bounds (guint8 **staddr, size_t *stsize)
1084 guint8 *current = (guint8 *)&stsize;
1085 mono_threads_core_get_stack_bounds (staddr, stsize);
1089 /* Sanity check the result */
1090 g_assert ((current > *staddr) && (current < *staddr + *stsize));
1092 /* When running under emacs, sometimes staddr is not aligned to a page size */
1093 *staddr = (guint8*)((gssize)*staddr & ~(mono_pagesize () - 1));
1097 mono_thread_info_yield (void)
1099 return mono_threads_core_yield ();
1103 mono_thread_info_tls_get (THREAD_INFO_TYPE *info, MonoTlsKey key)
1105 return ((MonoThreadInfo*)info)->tls [key];
1109 * mono_threads_info_tls_set:
1111 * Set the TLS key to VALUE in the info structure. This can be used to obtain
1112 * values of TLS variables for threads other than the current thread.
1113 * This should only be used for infrequently changing TLS variables, and it should
1114 * be paired with setting the real TLS variable since this provides no GC tracking.
1117 mono_thread_info_tls_set (THREAD_INFO_TYPE *info, MonoTlsKey key, gpointer value)
1119 ((MonoThreadInfo*)info)->tls [key] = value;
1123 * mono_thread_info_exit:
1125 * Exit the current thread.
1126 * This function doesn't return.
1129 mono_thread_info_exit (void)
1131 mono_threads_core_exit (0);
1135 * mono_thread_info_open_handle:
1137 * Return a io-layer/win32 handle for the current thread.
1138 * The handle need to be closed by calling CloseHandle () when it is no
1142 mono_thread_info_open_handle (void)
1144 return mono_threads_core_open_handle ();
1148 * mono_threads_open_thread_handle:
1150 * Return a io-layer/win32 handle for the thread identified by HANDLE/TID.
1151 * The handle need to be closed by calling CloseHandle () when it is no
1155 mono_threads_open_thread_handle (HANDLE handle, MonoNativeThreadId tid)
1157 return mono_threads_core_open_thread_handle (handle, tid);
1161 mono_thread_info_set_name (MonoNativeThreadId tid, const char *name)
1163 mono_threads_core_set_name (tid, name);
1167 * mono_thread_info_prepare_interrupt:
1169 * See wapi_prepare_interrupt ().
1172 mono_thread_info_prepare_interrupt (HANDLE thread_handle)
1174 return mono_threads_core_prepare_interrupt (thread_handle);
1178 mono_thread_info_finish_interrupt (gpointer wait_handle)
1180 mono_threads_core_finish_interrupt (wait_handle);
1184 mono_thread_info_interrupt (HANDLE thread_handle)
1186 gpointer wait_handle;
1188 wait_handle = mono_thread_info_prepare_interrupt (thread_handle);
1189 mono_thread_info_finish_interrupt (wait_handle);
1193 mono_thread_info_self_interrupt (void)
1195 mono_threads_core_self_interrupt ();
1199 mono_thread_info_clear_interruption (void)
1201 mono_threads_core_clear_interruption ();
1204 /* info must be self or be held in a hazard pointer. */
1206 mono_threads_add_async_job (MonoThreadInfo *info, MonoAsyncJob job)
1208 MonoAsyncJob old_job;
1210 old_job = (MonoAsyncJob) info->service_requests;
1213 } while (InterlockedCompareExchange (&info->service_requests, old_job | job, old_job) != old_job);
1218 mono_threads_consume_async_jobs (void)
1220 MonoThreadInfo *info = (MonoThreadInfo*)mono_native_tls_get_value (thread_info_key);
1223 return (MonoAsyncJob) 0;
1225 return (MonoAsyncJob) InterlockedExchange (&info->service_requests, 0);