/*
WARNING:
If we are trying to suspend a target that is on a critical region
and running a syscall we risk looping forever if @interrupt_kernel is FALSE.
So, be VERY carefull in calling this with @interrupt_kernel == FALSE.
Info is not put on a hazard pointer as a suspended thread cannot exit and be freed.
This function MUST be matched with mono_thread_info_finish_suspend or mono_thread_info_finish_suspend_and_resume
*/
MonoThreadInfo*
mono_thread_info_safe_suspend_sync (MonoNativeThreadId id, gboolean interrupt_kernel)
{
MonoThreadInfo *info = NULL;
int sleep_duration = 0;
/*FIXME: unify this with self-suspend*/
g_assert (id != mono_native_thread_id_get ());
mono_thread_info_suspend_lock ();
for (;;) {
const char *suspend_error = "Unknown error";
if (!(info = mono_thread_info_suspend_sync (id, interrupt_kernel, &suspend_error))) {
g_warning ("failed to suspend thread %p due to %s, hopefully it is dead", (gpointer)id, suspend_error);
mono_thread_info_suspend_unlock ();
return NULL;
}
/*WARNING: We now are in interrupt context until we resume the thread. */
if (!is_thread_in_critical_region (info))
break;
if (!mono_thread_info_core_resume (info)) {
g_warning ("failed to resume thread %p, hopefully it is dead", (gpointer)id);
mono_hazard_pointer_clear (mono_hazard_pointer_get (), 1);
mono_thread_info_suspend_unlock ();
return NULL;
}
THREADS_DEBUG ("restarted thread %p\n", (gpointer)id);
if (!sleep_duration) {
#ifdef HOST_WIN32
SwitchToThread ();
#else
sched_yield ();
#endif
}
else {
g_usleep (sleep_duration);
}
sleep_duration += 10;
}
/* XXX this clears HP 1, so we restated it again */
mono_atomic_store_release (&mono_thread_info_current ()->inside_critical_region, TRUE);
mono_thread_info_suspend_unlock ();
return info;
}
/*
* This is a very specific function whose only purpose is to
* break a given thread from socket syscalls.
*
* This only exists because linux won't fail a call to connect
* if the underlying is closed.
*
* TODO We should cleanup and unify this with the other syscall abort
* facility.
*/
void
mono_thread_info_abort_socket_syscall_for_close (MonoNativeThreadId tid)
{
MonoThreadHazardPointers *hp;
MonoThreadInfo *info;
if (tid == mono_native_thread_id_get () || !mono_threads_core_needs_abort_syscall ())
return;
hp = mono_hazard_pointer_get ();
info = mono_thread_info_lookup (tid); /*info on HP1*/
if (!info)
return;
if (mono_thread_info_run_state (info) > STATE_RUNNING) {
mono_hazard_pointer_clear (hp, 1);
return;
}
mono_thread_info_suspend_lock ();
mono_threads_core_abort_syscall (info);
mono_hazard_pointer_clear (hp, 1);
mono_thread_info_suspend_unlock ();
}
static void*
register_thread (MonoThreadInfo *info, gpointer baseptr)
{
int small_id = mono_thread_info_register_small_id ();
gboolean result;
mono_thread_info_set_tid (info, mono_native_thread_id_get ());
info->small_id = small_id;
MONO_SEM_INIT (&info->suspend_semaphore, 1);
MONO_SEM_INIT (&info->resume_semaphore, 0);
MONO_SEM_INIT (&info->finish_resume_semaphore, 0);
/*set TLS early so SMR works */
mono_native_tls_set_value (thread_info_key, info);
THREADS_DEBUG ("registering info %p tid %p small id %x\n", info, mono_thread_info_get_tid (info), info->small_id);
if (threads_callbacks.thread_register) {
if (threads_callbacks.thread_register (info, baseptr) == NULL) {
g_warning ("thread registation failed\n");
g_free (info);
return NULL;
}
}
mono_threads_platform_register (info);
info->thread_state = STATE_RUNNING;
mono_thread_info_suspend_lock ();
/*If this fail it means a given thread has been registered twice, which doesn't make sense. */
result = mono_thread_info_insert (info);
g_assert (result);
mono_thread_info_suspend_unlock ();
return info;
}
static void
on_gc_notification (GCEventType event)
{
MonoGCEvent e = (MonoGCEvent)event;
if (e == MONO_GC_EVENT_PRE_STOP_WORLD)
mono_thread_info_suspend_lock ();
else if (e == MONO_GC_EVENT_POST_START_WORLD)
mono_thread_info_suspend_unlock ();
if (e == MONO_GC_EVENT_START) {
if (mono_perfcounters)
mono_perfcounters->gc_collections0++;
mono_stats.major_gc_count ++;
gc_start_time = mono_100ns_ticks ();
} else if (e == MONO_GC_EVENT_END) {
if (mono_perfcounters) {
guint64 heap_size = GC_get_heap_size ();
guint64 used_size = heap_size - GC_get_free_bytes ();
mono_perfcounters->gc_total_bytes = used_size;
mono_perfcounters->gc_committed_bytes = heap_size;
mono_perfcounters->gc_reserved_bytes = heap_size;
mono_perfcounters->gc_gen0size = heap_size;
}
mono_stats.major_gc_time_usecs += (mono_100ns_ticks () - gc_start_time) / 10;
mono_trace_message (MONO_TRACE_GC, "gc took %d usecs", (mono_100ns_ticks () - gc_start_time) / 10);
}
mono_profiler_gc_event (e, 0);
}
gboolean
mono_thread_info_resume (MonoNativeThreadId tid)
{
gboolean result; /* don't initialize it so the compiler can catch unitilized paths. */
MonoThreadHazardPointers *hp = mono_hazard_pointer_get ();
MonoThreadInfo *info;
THREADS_SUSPEND_DEBUG ("RESUMING tid %p\n", (void*)tid);
mono_thread_info_suspend_lock ();
info = mono_thread_info_lookup (tid); /*info on HP1*/
if (!info) {
result = FALSE;
goto cleanup;
}
result = mono_thread_info_core_resume (info);
//Wait for the pending resume to finish
mono_threads_wait_pending_operations ();
cleanup:
mono_thread_info_suspend_unlock ();
mono_hazard_pointer_clear (hp, 1);
return result;
}
/*
* This is a very specific function whose only purpose is to
* break a given thread from socket syscalls.
*
* This only exists because linux won't fail a call to connect
* if the underlying is closed.
*
* TODO We should cleanup and unify this with the other syscall abort
* facility.
*/
void
mono_thread_info_abort_socket_syscall_for_close (MonoNativeThreadId tid)
{
MonoThreadHazardPointers *hp;
MonoThreadInfo *info;
if (tid == mono_native_thread_id_get () || !mono_threads_core_needs_abort_syscall ())
return;
hp = mono_hazard_pointer_get ();
info = mono_thread_info_lookup (tid);
if (!info)
return;
if (mono_thread_info_run_state (info) == STATE_DETACHED) {
mono_hazard_pointer_clear (hp, 1);
return;
}
mono_thread_info_suspend_lock ();
mono_threads_begin_global_suspend ();
mono_threads_core_abort_syscall (info);
mono_threads_wait_pending_operations ();
mono_hazard_pointer_clear (hp, 1);
mono_threads_end_global_suspend ();
mono_thread_info_suspend_unlock ();
}
void
mono_thread_info_safe_suspend_and_run (MonoNativeThreadId id, gboolean interrupt_kernel, MonoSuspendThreadCallback callback, gpointer user_data)
{
int result;
MonoThreadInfo *info = NULL;
MonoThreadHazardPointers *hp = mono_hazard_pointer_get ();
THREADS_SUSPEND_DEBUG ("SUSPENDING tid %p\n", (void*)id);
/*FIXME: unify this with self-suspend*/
g_assert (id != mono_native_thread_id_get ());
mono_thread_info_suspend_lock ();
mono_threads_begin_global_suspend ();
info = suspend_sync_nolock (id, interrupt_kernel);
if (!info)
goto done;
switch (result = callback (info, user_data)) {
case MonoResumeThread:
mono_hazard_pointer_set (hp, 1, info);
mono_thread_info_core_resume (info);
mono_threads_wait_pending_operations ();
break;
case KeepSuspended:
break;
default:
g_error ("Invalid suspend_and_run callback return value %d", result);
}
done:
mono_hazard_pointer_clear (hp, 1);
mono_threads_end_global_suspend ();
mono_thread_info_suspend_unlock ();
}
static void
on_gc_notification (GCEventType event)
{
MonoGCEvent e = (MonoGCEvent)event;
switch (e) {
case MONO_GC_EVENT_PRE_STOP_WORLD:
MONO_GC_WORLD_STOP_BEGIN ();
mono_thread_info_suspend_lock ();
break;
case MONO_GC_EVENT_POST_STOP_WORLD:
MONO_GC_WORLD_STOP_END ();
break;
case MONO_GC_EVENT_PRE_START_WORLD:
MONO_GC_WORLD_RESTART_BEGIN (1);
break;
case MONO_GC_EVENT_POST_START_WORLD:
MONO_GC_WORLD_RESTART_END (1);
mono_thread_info_suspend_unlock ();
break;
case MONO_GC_EVENT_START:
MONO_GC_BEGIN (1);
#ifndef DISABLE_PERFCOUNTERS
if (mono_perfcounters)
mono_perfcounters->gc_collections0++;
#endif
gc_stats.major_gc_count ++;
gc_start_time = mono_100ns_ticks ();
break;
case MONO_GC_EVENT_END:
MONO_GC_END (1);
#if defined(ENABLE_DTRACE) && defined(__sun__)
/* This works around a dtrace -G problem on Solaris.
Limit its actual use to when the probe is enabled. */
if (MONO_GC_END_ENABLED ())
sleep(0);
#endif
#ifndef DISABLE_PERFCOUNTERS
if (mono_perfcounters) {
guint64 heap_size = GC_get_heap_size ();
guint64 used_size = heap_size - GC_get_free_bytes ();
mono_perfcounters->gc_total_bytes = used_size;
mono_perfcounters->gc_committed_bytes = heap_size;
mono_perfcounters->gc_reserved_bytes = heap_size;
mono_perfcounters->gc_gen0size = heap_size;
}
#endif
gc_stats.major_gc_time_usecs += (mono_100ns_ticks () - gc_start_time) / 10;
mono_trace_message (MONO_TRACE_GC, "gc took %d usecs", (mono_100ns_ticks () - gc_start_time) / 10);
break;
}
mono_profiler_gc_event (e, 0);
}
static void
unregister_thread (void *arg)
{
MonoThreadInfo *info = arg;
int small_id = info->small_id;
g_assert (info);
THREADS_DEBUG ("unregistering info %p\n", info);
/*
* TLS destruction order is not reliable so small_id might be cleaned up
* before us.
*/
mono_native_tls_set_value (small_id_key, GUINT_TO_POINTER (info->small_id + 1));
info->thread_state = STATE_SHUTTING_DOWN;
mono_thread_info_suspend_lock ();
if (threads_callbacks.thread_unregister)
threads_callbacks.thread_unregister (info);
mono_threads_unregister_current_thread (info);
info->thread_state = STATE_DEAD;
mono_thread_info_suspend_unlock ();
/*now it's safe to free the thread info.*/
mono_thread_hazardous_free_or_queue (info, free_thread_info, TRUE, FALSE);
mono_thread_small_id_free (small_id);
}
/*
WARNING:
If we are trying to suspend a target that is on a critical region
and running a syscall we risk looping forever if @interrupt_kernel is FALSE.
So, be VERY carefull in calling this with @interrupt_kernel == FALSE.
*/
MonoThreadInfo*
mono_thread_info_safe_suspend_sync (MonoNativeThreadId id, gboolean interrupt_kernel)
{
MonoThreadInfo *info = NULL;
int sleep_duration = 0;
/*FIXME: unify this with self-suspend*/
g_assert (id != mono_native_thread_id_get ());
mono_thread_info_suspend_lock ();
for (;;) {
if (!(info = mono_thread_info_suspend_sync (id, interrupt_kernel))) {
g_warning ("failed to suspend thread %p, hopefully it is dead", (gpointer)id);
mono_thread_info_suspend_unlock ();
return NULL;
}
/*WARNING: We now are in interrupt context until we resume the thread. */
if (!is_thread_in_critical_region (info))
break;
if (!mono_thread_info_resume (id)) {
g_warning ("failed to result thread %p, hopefully it is dead", (gpointer)id);
mono_thread_info_suspend_unlock ();
return NULL;
}
THREADS_DEBUG ("restarted thread %p\n", (gpointer)id);
if (!sleep_duration) {
#ifdef HOST_WIN32
SwitchToThread ();
#else
sched_yield ();
#endif
}
else {
g_usleep (sleep_duration);
}
sleep_duration += 10;
}
mono_thread_info_suspend_unlock ();
return info;
}
static void
unregister_thread (void *arg)
{
MonoThreadInfo *info = (MonoThreadInfo *) arg;
int small_id = info->small_id;
g_assert (info);
THREADS_DEBUG ("unregistering info %p\n", info);
mono_native_tls_set_value (thread_exited_key, GUINT_TO_POINTER (1));
mono_threads_core_unregister (info);
/*
* TLS destruction order is not reliable so small_id might be cleaned up
* before us.
*/
#ifndef HAVE_KW_THREAD
mono_native_tls_set_value (small_id_key, GUINT_TO_POINTER (info->small_id + 1));
#endif
/*
First perform the callback that requires no locks.
This callback has the potential of taking other locks, so we do it before.
After it completes, the thread remains functional.
*/
if (threads_callbacks.thread_detach)
threads_callbacks.thread_detach (info);
/*
Since the thread info lock is taken from within blocking sections, we can't check from there, so it must be done here.
This ensures that we won't lose any suspend requests as a suspend initiator must hold the lock.
Once we're holding the suspend lock, no threads can suspend us and once we unregister, no thread can find us.
*/
MONO_PREPARE_BLOCKING
mono_thread_info_suspend_lock ();
MONO_FINISH_BLOCKING
/*
Now perform the callback that must be done under locks.
This will render the thread useless and non-suspendable, so it must
be done while holding the suspend lock to give no other thread chance
to suspend it.
*/
if (threads_callbacks.thread_unregister)
threads_callbacks.thread_unregister (info);
mono_threads_unregister_current_thread (info);
mono_threads_transition_detach (info);
mono_thread_info_suspend_unlock ();
/*now it's safe to free the thread info.*/
mono_thread_hazardous_free_or_queue (info, free_thread_info, TRUE, FALSE);
mono_thread_small_id_free (small_id);
}
static void*
register_thread (MonoThreadInfo *info, gpointer baseptr)
{
size_t stsize = 0;
guint8 *staddr = NULL;
int small_id = mono_thread_info_register_small_id ();
gboolean result;
mono_thread_info_set_tid (info, mono_native_thread_id_get ());
info->small_id = small_id;
info->handle = g_new0 (MonoThreadHandle, 1);
mono_refcount_init (info->handle, thread_handle_destroy);
mono_os_event_init (&info->handle->event, FALSE);
mono_os_sem_init (&info->resume_semaphore, 0);
/*set TLS early so SMR works */
mono_native_tls_set_value (thread_info_key, info);
THREADS_DEBUG ("registering info %p tid %p small id %x\n", info, mono_thread_info_get_tid (info), info->small_id);
if (threads_callbacks.thread_register) {
if (threads_callbacks.thread_register (info, baseptr) == NULL) {
// g_warning ("thread registation failed\n");
mono_native_tls_set_value (thread_info_key, NULL);
g_free (info);
return NULL;
}
}
mono_thread_info_get_stack_bounds (&staddr, &stsize);
g_assert (staddr);
g_assert (stsize);
info->stack_start_limit = staddr;
info->stack_end = staddr + stsize;
info->stackdata = g_byte_array_new ();
mono_threads_suspend_register (info);
/*
Transition it before taking any locks or publishing itself to reduce the chance
of others witnessing a detached thread.
We can reasonably expect that until this thread gets published, no other thread will
try to manipulate it.
*/
mono_threads_transition_attach (info);
mono_thread_info_suspend_lock ();
/*If this fail it means a given thread has been registered twice, which doesn't make sense. */
result = mono_thread_info_insert (info);
g_assert (result);
mono_thread_info_suspend_unlock ();
return info;
}
static void
unregister_thread (void *arg)
{
MonoThreadInfo *info = (MonoThreadInfo *) arg;
int small_id = info->small_id;
g_assert (info);
THREADS_DEBUG ("unregistering info %p\n", info);
mono_native_tls_set_value (thread_exited_key, GUINT_TO_POINTER (1));
mono_threads_core_unregister (info);
/*
* TLS destruction order is not reliable so small_id might be cleaned up
* before us.
*/
#ifndef HAVE_KW_THREAD
mono_native_tls_set_value (small_id_key, GUINT_TO_POINTER (info->small_id + 1));
#endif
/*
First perform the callback that requires no locks.
This callback has the potential of taking other locks, so we do it before.
After it completes, the thread remains functional.
*/
if (threads_callbacks.thread_detach)
threads_callbacks.thread_detach (info);
mono_thread_info_suspend_lock ();
/*
Now perform the callback that must be done under locks.
This will render the thread useless and non-suspendable, so it must
be done while holding the suspend lock to give no other thread chance
to suspend it.
*/
if (threads_callbacks.thread_unregister)
threads_callbacks.thread_unregister (info);
mono_threads_unregister_current_thread (info);
mono_threads_transition_detach (info);
mono_thread_info_suspend_unlock ();
g_byte_array_free (info->stackdata, /*free_segment=*/TRUE);
/*now it's safe to free the thread info.*/
mono_thread_hazardous_free_or_queue (info, free_thread_info, TRUE, FALSE);
mono_thread_small_id_free (small_id);
}
/*
WARNING:
If we are trying to suspend a target that is on a critical region
and running a syscall we risk looping forever if @interrupt_kernel is FALSE.
So, be VERY carefull in calling this with @interrupt_kernel == FALSE.
Info is not put on a hazard pointer as a suspended thread cannot exit and be freed.
This function MUST be matched with mono_thread_info_finish_suspend or mono_thread_info_finish_suspend_and_resume
*/
MonoThreadInfo*
mono_thread_info_safe_suspend_sync (MonoNativeThreadId id, gboolean interrupt_kernel)
{
MonoThreadInfo *info = NULL;
THREADS_SUSPEND_DEBUG ("SUSPENDING tid %p\n", (void*)id);
/*FIXME: unify this with self-suspend*/
g_assert (id != mono_native_thread_id_get ());
mono_thread_info_suspend_lock ();
mono_threads_begin_global_suspend ();
info = suspend_sync_nolock (id, interrupt_kernel);
/* XXX this clears HP 1, so we restated it again */
// mono_atomic_store_release (&mono_thread_info_current ()->inside_critical_region, TRUE);
mono_threads_end_global_suspend ();
mono_thread_info_suspend_unlock ();
return info;
}
static void
release_gc_locks (void)
{
mono_thread_info_suspend_unlock ();
UNLOCK_INTERRUPTION;
}
static void
unregister_thread (void *arg)
{
gpointer gc_unsafe_stackdata;
MonoThreadInfo *info;
int small_id;
info = (MonoThreadInfo *) arg;
g_assert (info);
g_assert (mono_thread_info_is_current (info));
g_assert (mono_thread_info_is_live (info));
small_id = info->small_id;
/* We only enter the GC unsafe region, as when exiting this function, the thread
* will be detached, and the current MonoThreadInfo* will be destroyed. */
mono_threads_enter_gc_unsafe_region_unbalanced_with_info (info, &gc_unsafe_stackdata);
THREADS_DEBUG ("unregistering info %p\n", info);
mono_native_tls_set_value (thread_exited_key, GUINT_TO_POINTER (1));
mono_threads_platform_unregister (info);
/*
* TLS destruction order is not reliable so small_id might be cleaned up
* before us.
*/
#ifndef HAVE_KW_THREAD
mono_native_tls_set_value (small_id_key, GUINT_TO_POINTER (info->small_id + 1));
#endif
/*
First perform the callback that requires no locks.
This callback has the potential of taking other locks, so we do it before.
After it completes, the thread remains functional.
*/
if (threads_callbacks.thread_detach)
threads_callbacks.thread_detach (info);
mono_thread_info_suspend_lock_with_info (info);
/*
Now perform the callback that must be done under locks.
This will render the thread useless and non-suspendable, so it must
be done while holding the suspend lock to give no other thread chance
to suspend it.
*/
if (threads_callbacks.thread_unregister)
threads_callbacks.thread_unregister (info);
mono_threads_unregister_current_thread (info);
mono_threads_transition_detach (info);
mono_thread_info_suspend_unlock ();
g_byte_array_free (info->stackdata, /*free_segment=*/TRUE);
/*now it's safe to free the thread info.*/
mono_thread_hazardous_try_free (info, free_thread_info);
/* Pump the HP queue */
mono_thread_hazardous_try_free_some ();
mono_thread_small_id_free (small_id);
}
