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mono-threads.c
2118 lines (1774 loc) · 61.5 KB
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mono-threads.c
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/**
* \file
* Low-level threading
*
* Author:
* Rodrigo Kumpera (kumpera@gmail.com)
*
* Copyright 2011 Novell, Inc (http://www.novell.com)
* Copyright 2011 Xamarin, Inc (http://www.xamarin.com)
* Licensed under the MIT license. See LICENSE file in the project root for full license information.
*/
#include <config.h>
/* enable pthread extensions */
#ifdef TARGET_MACH
#define _DARWIN_C_SOURCE
#endif
#include <mono/utils/mono-compiler.h>
#include <mono/utils/mono-os-semaphore.h>
#include <mono/utils/mono-threads.h>
#include <mono/utils/mono-tls.h>
#include <mono/utils/hazard-pointer.h>
#include <mono/utils/mono-memory-model.h>
#include <mono/utils/mono-mmap.h>
#include <mono/utils/atomic.h>
#include <mono/utils/mono-time.h>
#include <mono/utils/mono-lazy-init.h>
#include <mono/utils/mono-coop-mutex.h>
#include <mono/utils/mono-coop-semaphore.h>
#include <mono/utils/mono-threads-coop.h>
#include <mono/utils/mono-threads-debug.h>
#include <mono/utils/os-event.h>
#include <mono/utils/w32api.h>
#include <errno.h>
#include <mono/utils/mono-errno.h>
#if defined(__MACH__)
#include <mono/utils/mach-support.h>
#endif
/*
Mutex that makes sure only a single thread can be suspending others.
Suspend is a very racy operation since it requires restarting until
the target thread is not on an unsafe region.
We could implement this using critical regions, but would be much much
harder for an operation that is hardly performance critical.
The GC has to acquire this lock before starting a STW to make sure
a runtime suspend won't make it wronly see a thread in a safepoint
when it is in fact not.
This has to be a naked locking primitive, and not a coop aware one, as
it needs to be usable when destroying thread_info_key, the TLS key for
the current MonoThreadInfo. In this case, mono_thread_info_current_unchecked,
(which is used inside MONO_ENTER_GC_SAFE), would return NULL, leading
to an assertion error. We then simply switch state manually in
mono_thread_info_suspend_lock_with_info.
*/
static MonoSemType global_suspend_semaphore;
static size_t thread_info_size;
static MonoThreadInfoCallbacks threads_callbacks;
const MonoThreadInfoRuntimeCallbacks *mono_runtime_callbacks;
static MonoNativeTlsKey thread_info_key, thread_exited_key;
#ifdef MONO_KEYWORD_THREAD
static MONO_KEYWORD_THREAD gint32 tls_small_id = -1;
#else
static MonoNativeTlsKey small_id_key;
#endif
static MonoLinkedListSet thread_list;
static gboolean mono_threads_inited = FALSE;
static MonoSemType suspend_semaphore;
static size_t pending_suspends;
static mono_mutex_t join_mutex;
#define mono_thread_info_run_state(info) (((MonoThreadInfo*)info)->thread_state & THREAD_STATE_MASK)
/*warn at 50 ms*/
#define SLEEP_DURATION_BEFORE_WARNING (50)
/*never aborts */
#define SLEEP_DURATION_BEFORE_ABORT MONO_INFINITE_WAIT
static guint32 sleepWarnDuration = SLEEP_DURATION_BEFORE_WARNING,
sleepAbortDuration = SLEEP_DURATION_BEFORE_ABORT;
static int suspend_posts, resume_posts, abort_posts, waits_done, pending_ops;
void
mono_threads_notify_initiator_of_abort (MonoThreadInfo* info)
{
THREADS_SUSPEND_DEBUG ("[INITIATOR-NOTIFY-ABORT] %p\n", mono_thread_info_get_tid (info));
mono_atomic_inc_i32 (&abort_posts);
mono_os_sem_post (&suspend_semaphore);
}
void
mono_threads_notify_initiator_of_suspend (MonoThreadInfo* info)
{
THREADS_SUSPEND_DEBUG ("[INITIATOR-NOTIFY-SUSPEND] %p\n", mono_thread_info_get_tid (info));
// check that the thread is really in a valid suspended state.
g_assert (mono_thread_info_get_suspend_state (info) != NULL);
mono_atomic_inc_i32 (&suspend_posts);
mono_os_sem_post (&suspend_semaphore);
}
void
mono_threads_notify_initiator_of_resume (MonoThreadInfo* info)
{
THREADS_SUSPEND_DEBUG ("[INITIATOR-NOTIFY-RESUME] %p\n", mono_thread_info_get_tid (info));
mono_atomic_inc_i32 (&resume_posts);
mono_os_sem_post (&suspend_semaphore);
}
typedef enum {
BeginSuspendFail = 0,
BeginSuspendOkPreemptive = 1,
BeginSuspendOkCooperative = 2,
BeginSuspendOkNoWait = 3,
} BeginSuspendResult;
static BeginSuspendResult
begin_cooperative_suspend (MonoThreadInfo *info)
{
/* There's nothing else to do after we async request the thread to suspend */
mono_threads_add_to_pending_operation_set (info);
return BeginSuspendOkCooperative;
}
static BeginSuspendResult
begin_preemptive_suspend (MonoThreadInfo *info, gboolean interrupt_kernel)
{
if (mono_threads_suspend_begin_async_suspend (info, interrupt_kernel))
return BeginSuspendOkPreemptive;
else
return BeginSuspendFail;
}
static BeginSuspendResult
begin_suspend_for_running_thread (MonoThreadInfo *info, gboolean interrupt_kernel)
{
/* If we're using full cooperative suspend or hybrid suspend,
* cooperatively suspend RUNNING threads */
if (mono_threads_are_safepoints_enabled ())
return begin_cooperative_suspend (info);
else
return begin_preemptive_suspend (info, interrupt_kernel);
}
static gboolean
thread_is_cooperative_suspend_aware (MonoThreadInfo *info)
{
return (mono_threads_is_cooperative_suspension_enabled () || mono_atomic_load_i32 (&(info->coop_aware_thread)));
}
static BeginSuspendResult
begin_suspend_for_blocking_thread (MonoThreadInfo *info, gboolean interrupt_kernel, MonoThreadSuspendPhase phase, gboolean coop_aware_thread, gboolean *did_interrupt)
{
// if a thread can't transition to blocking, we certainly shouldn't be
// trying to suspend it like it's blocking.
g_assert (mono_threads_is_blocking_transition_enabled ());
// with hybrid suspend, preemptively suspend blocking threads (if thread is not coop aware),
// otherwise blocking already counts as suspended.
if (mono_threads_is_hybrid_suspension_enabled () && !coop_aware_thread) {
if (did_interrupt) {
*did_interrupt = interrupt_kernel;
}
switch (phase) {
case MONO_THREAD_SUSPEND_PHASE_INITIAL:
/* In hybrid suspend, in the first phase, a thread in
* blocking can continue running (and possibly
* self-suspend). We'll preemptively suspend it in the
* second phase, if thread is not coop aware. */
return BeginSuspendOkNoWait;
case MONO_THREAD_SUSPEND_PHASE_MOPUP:
return begin_preemptive_suspend (info, interrupt_kernel);
default:
g_assert_not_reached ();
}
} else {
if (did_interrupt)
*did_interrupt = FALSE;
// In full cooperative suspend, treat a thread in BLOCKING as
// already suspended and don't wait for it.
return BeginSuspendOkNoWait;
}
}
static gboolean
check_async_suspend (MonoThreadInfo *info, BeginSuspendResult result)
{
switch (result) {
case BeginSuspendOkCooperative:
return TRUE;
case BeginSuspendOkPreemptive:
return mono_threads_suspend_check_suspend_result (info);
case BeginSuspendFail:
return FALSE;
case BeginSuspendOkNoWait:
return TRUE;
default:
g_assert_not_reached ();
}
}
static void
resume_async_suspended (MonoThreadInfo *info)
{
if (mono_threads_is_cooperative_suspension_enabled () && !mono_threads_is_hybrid_suspension_enabled ())
g_assert_not_reached ();
g_assert (mono_threads_suspend_begin_async_resume (info));
}
static void
resume_self_suspended (MonoThreadInfo* info)
{
THREADS_SUSPEND_DEBUG ("**BEGIN self-resume %p\n", mono_thread_info_get_tid (info));
mono_os_sem_post (&info->resume_semaphore);
}
void
mono_thread_info_wait_for_resume (MonoThreadInfo* info)
{
int res;
THREADS_SUSPEND_DEBUG ("**WAIT self-resume %p\n", mono_thread_info_get_tid (info));
res = mono_os_sem_wait (&info->resume_semaphore, MONO_SEM_FLAGS_NONE);
g_assert (res != -1);
}
static void
resume_blocking_suspended (MonoThreadInfo* info)
{
THREADS_SUSPEND_DEBUG ("**BEGIN blocking-resume %p\n", mono_thread_info_get_tid (info));
mono_os_sem_post (&info->resume_semaphore);
}
void
mono_threads_add_to_pending_operation_set (MonoThreadInfo* info)
{
THREADS_SUSPEND_DEBUG ("added %p to pending suspend\n", mono_thread_info_get_tid (info));
++pending_suspends;
mono_atomic_inc_i32 (&pending_ops);
}
void
mono_threads_begin_global_suspend (void)
{
size_t ps = pending_suspends;
if (G_UNLIKELY (ps != 0))
g_error ("pending_suspends = %d, but must be 0", ps);
THREADS_SUSPEND_DEBUG ("------ BEGIN GLOBAL OP sp %d rp %d ap %d wd %d po %d (sp + rp + ap == wd) (wd == po)\n", suspend_posts, resume_posts,
abort_posts, waits_done, pending_ops);
g_assert ((suspend_posts + resume_posts + abort_posts) == waits_done);
mono_threads_coop_begin_global_suspend ();
}
void
mono_threads_end_global_suspend (void)
{
size_t ps = pending_suspends;
if (G_UNLIKELY (ps != 0))
g_error ("pending_suspends = %d, but must be 0", ps);
THREADS_SUSPEND_DEBUG ("------ END GLOBAL OP sp %d rp %d ap %d wd %d po %d\n", suspend_posts, resume_posts,
abort_posts, waits_done, pending_ops);
g_assert ((suspend_posts + resume_posts + abort_posts) == waits_done);
mono_threads_coop_end_global_suspend ();
}
static void
dump_threads (void)
{
MonoThreadInfo *cur = mono_thread_info_current ();
g_async_safe_printf ("STATE CUE CARD: (? means a positive number, usually 1 or 2, * means any number)\n");
g_async_safe_printf ("\t0x0\t- starting (GOOD, unless the thread is running managed code)\n");
g_async_safe_printf ("\t0x1\t- detached (GOOD, unless the thread is running managed code)\n");
g_async_safe_printf ("\t0x2\t- running (BAD, unless it's the gc thread)\n");
g_async_safe_printf ("\t0x?03\t- async suspended (GOOD)\n");
g_async_safe_printf ("\t0x?04\t- self suspended (GOOD)\n");
g_async_safe_printf ("\t0x?05\t- async suspend requested (BAD)\n");
g_async_safe_printf ("\t0x6\t- blocking (BAD, unless there's no suspend initiator)\n");
g_async_safe_printf ("\t0x?07\t- blocking async suspended (GOOD)\n");
g_async_safe_printf ("\t0x?08\t- blocking self suspended (GOOD)\n");
g_async_safe_printf ("\t0x?09\t- blocking suspend requested (BAD in coop; GOOD in hybrid)\n");
FOREACH_THREAD_SAFE_ALL (info) {
#ifdef TARGET_MACH
char thread_name [256] = { 0 };
pthread_getname_np (mono_thread_info_get_tid (info), thread_name, 255);
g_async_safe_printf ("--thread %p id %p [%p] (%s) state %x %s\n", info, (void *) mono_thread_info_get_tid (info), (void*)(size_t)info->native_handle, thread_name, info->thread_state, info == cur ? "GC INITIATOR" : "" );
#else
g_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" : "" );
#endif
} FOREACH_THREAD_SAFE_END
}
gboolean
mono_threads_wait_pending_operations (void)
{
int i;
int c = pending_suspends;
/* Wait threads to park */
THREADS_SUSPEND_DEBUG ("[INITIATOR-WAIT-COUNT] %d\n", c);
if (pending_suspends) {
MonoStopwatch suspension_time;
mono_stopwatch_start (&suspension_time);
for (i = 0; i < pending_suspends; ++i) {
THREADS_SUSPEND_DEBUG ("[INITIATOR-WAIT-WAITING]\n");
mono_atomic_inc_i32 (&waits_done);
if (mono_os_sem_timedwait (&suspend_semaphore, sleepAbortDuration, MONO_SEM_FLAGS_NONE) == MONO_SEM_TIMEDWAIT_RET_SUCCESS)
continue;
mono_stopwatch_stop (&suspension_time);
dump_threads ();
g_async_safe_printf ("WAITING for %d threads, got %d suspended\n", (int)pending_suspends, i);
g_error ("suspend_thread suspend took %d ms, which is more than the allowed %d ms", (int)mono_stopwatch_elapsed_ms (&suspension_time), sleepAbortDuration);
}
mono_stopwatch_stop (&suspension_time);
THREADS_SUSPEND_DEBUG ("Suspending %d threads took %d ms.\n", (int)pending_suspends, (int)mono_stopwatch_elapsed_ms (&suspension_time));
}
pending_suspends = 0;
return c > 0;
}
//Thread initialization code
static void
mono_hazard_pointer_clear_all (MonoThreadHazardPointers *hp, int retain)
{
if (retain != 0)
mono_hazard_pointer_clear (hp, 0);
if (retain != 1)
mono_hazard_pointer_clear (hp, 1);
if (retain != 2)
mono_hazard_pointer_clear (hp, 2);
}
/*
If return non null Hazard Pointer 1 holds the return value.
*/
MonoThreadInfo*
mono_thread_info_lookup (MonoNativeThreadId id)
{
MonoThreadHazardPointers *hp = mono_hazard_pointer_get ();
if (!mono_lls_find (&thread_list, hp, (uintptr_t)id)) {
mono_hazard_pointer_clear_all (hp, -1);
return NULL;
}
mono_hazard_pointer_clear_all (hp, 1);
return (MonoThreadInfo *) mono_hazard_pointer_get_val (hp, 1);
}
static gboolean
mono_thread_info_insert (MonoThreadInfo *info)
{
MonoThreadHazardPointers *hp = mono_hazard_pointer_get ();
if (!mono_lls_insert (&thread_list, hp, (MonoLinkedListSetNode*)info)) {
mono_hazard_pointer_clear_all (hp, -1);
return FALSE;
}
mono_hazard_pointer_clear_all (hp, -1);
return TRUE;
}
static gboolean
mono_thread_info_remove (MonoThreadInfo *info)
{
MonoThreadHazardPointers *hp = mono_hazard_pointer_get ();
gboolean res;
THREADS_DEBUG ("removing info %p\n", info);
res = mono_lls_remove (&thread_list, hp, (MonoLinkedListSetNode*)info);
mono_hazard_pointer_clear_all (hp, -1);
return res;
}
static void
free_thread_info (gpointer mem)
{
MonoThreadInfo *info = (MonoThreadInfo *) mem;
mono_os_sem_destroy (&info->resume_semaphore);
mono_threads_suspend_free (info);
g_free (info);
}
/*
* mono_thread_info_register_small_id
*
* Registers a small ID for the current thread. This is a 16-bit value uniquely
* identifying the current thread. If the current thread already has a small ID
* assigned, that small ID will be returned; otherwise, the newly assigned small
* ID is returned.
*/
int
mono_thread_info_register_small_id (void)
{
int small_id = mono_thread_info_get_small_id ();
if (small_id != -1)
return small_id;
small_id = mono_thread_small_id_alloc ();
#ifdef MONO_KEYWORD_THREAD
tls_small_id = small_id;
#else
mono_native_tls_set_value (small_id_key, GUINT_TO_POINTER (small_id + 1));
#endif
return small_id;
}
static void
thread_handle_destroy (gpointer data)
{
MonoThreadHandle *thread_handle;
thread_handle = (MonoThreadHandle*) data;
mono_os_event_destroy (&thread_handle->event);
g_free (thread_handle);
}
static gboolean
register_thread (MonoThreadInfo *info)
{
size_t stsize = 0;
guint8 *staddr = NULL;
gboolean result;
info->small_id = mono_thread_info_register_small_id ();
mono_thread_info_set_tid (info, mono_native_thread_id_get ());
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);
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 ();
info->internal_thread_gchandle = G_MAXUINT32;
info->profiler_signal_ack = 1;
#ifdef USE_WINDOWS_BACKEND
info->windows_tib = (PNT_TIB)NtCurrentTeb ();
info->win32_apc_info = 0;
info->win32_apc_info_io_handle = INVALID_HANDLE_VALUE;
#endif
mono_threads_suspend_register (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_attach) {
if (!threads_callbacks.thread_attach (info)) {
// g_warning ("thread registation failed\n");
mono_native_tls_set_value (thread_info_key, NULL);
return FALSE;
}
}
/*
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 TRUE;
}
static void
mono_thread_info_suspend_lock_with_info (MonoThreadInfo *info);
static void
mono_threads_signal_thread_handle (MonoThreadHandle* thread_handle);
static void
unregister_thread (void *arg)
{
MONO_STACKDATA (gc_unsafe_stackdata);
MonoThreadInfo *info;
int small_id;
gboolean result;
MonoThreadHandle* handle;
info = (MonoThreadInfo *) arg;
g_assertf (info, ""); // f includes __func__
g_assert (mono_thread_info_is_current (info));
g_assert (mono_thread_info_is_live (info));
/* 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);
/* Need to be in GC Unsafe to pump the HP queue - some of the cleanup
* methods need to use coop-aware locks. For example: jit_info_table_free_duplicate.
*/
/* Pump the HP queue while the thread is alive.*/
mono_thread_hazardous_try_free_some ();
small_id = info->small_id;
THREADS_DEBUG ("unregistering info %p\n", info);
mono_native_tls_set_value (thread_exited_key, GUINT_TO_POINTER (1));
/*
* TLS destruction order is not reliable so small_id might be cleaned up
* before us.
*/
#ifndef MONO_KEYWORD_THREAD
mono_native_tls_set_value (small_id_key, GUINT_TO_POINTER (info->small_id + 1));
#endif
/* we need to duplicate it, as the info->handle is going
* to be closed when unregistering from the platform */
handle = mono_threads_open_thread_handle (info->handle);
/*
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_detach_with_lock)
threads_callbacks.thread_detach_with_lock (info);
/* The thread is no longer active, so unref its handle */
mono_threads_close_thread_handle (info->handle);
info->handle = NULL;
result = mono_thread_info_remove (info);
g_assert (result);
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);
mono_thread_small_id_free (small_id);
mono_native_tls_set_value (small_id_key, NULL);
mono_threads_signal_thread_handle (handle);
mono_threads_close_thread_handle (handle);
mono_native_tls_set_value (thread_info_key, NULL);
}
static void
thread_exited_dtor (void *arg)
{
#if defined(__MACH__)
/*
* Since we use pthread dtors to clean up thread data, if a thread
* is attached to the runtime by another pthread dtor after our dtor
* has ran, it will never be detached, leading to various problems
* since the thread ids etc. will be reused while they are still in
* the threads hashtables etc.
* Dtors are called in a loop until all user tls entries are 0,
* but the loop has a maximum count (4), so if we set the tls
* variable every time, it will remain set when system tls dtors
* are ran. This allows mono_thread_info_is_exiting () to detect
* whenever the thread is exiting, even if it is executed from a
* system tls dtor (i.e. obj-c dealloc methods).
*/
mono_native_tls_set_value (thread_exited_key, GUINT_TO_POINTER (1));
#endif
}
MonoThreadInfo*
mono_thread_info_current_unchecked (void)
{
return mono_threads_inited ? (MonoThreadInfo*)mono_native_tls_get_value (thread_info_key) : NULL;
}
MonoThreadInfo*
mono_thread_info_current (void)
{
MonoThreadInfo *info = (MonoThreadInfo*)mono_native_tls_get_value (thread_info_key);
if (info)
return info;
info = mono_thread_info_lookup (mono_native_thread_id_get ()); /*info on HP1*/
/*
We might be called during thread cleanup, but we cannot be called after cleanup as happened.
The way to distinguish between before, during and after cleanup is the following:
-If the TLS key is set, cleanup has not begun;
-If the TLS key is clean, but the thread remains registered, cleanup is in progress;
-If the thread is nowhere to be found, cleanup has finished.
We cannot function after cleanup since there's no way to ensure what will happen.
*/
g_assertf (info, ""); // f includes __func__
/*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 */
mono_hazard_pointer_clear (mono_hazard_pointer_get (), 1);
return info;
}
/*
* mono_thread_info_get_small_id
*
* Retrieve the small ID for the current thread. This is a 16-bit value uniquely
* identifying the current thread. Returns -1 if the current thread doesn't have
* a small ID assigned.
*
* To ensure that the calling thread has a small ID assigned, call either
* mono_thread_info_attach or mono_thread_info_register_small_id.
*/
int
mono_thread_info_get_small_id (void)
{
#ifdef MONO_KEYWORD_THREAD
return tls_small_id;
#else
gpointer val = mono_native_tls_get_value (small_id_key);
if (!val)
return -1;
return GPOINTER_TO_INT (val) - 1;
#endif
}
MonoLinkedListSet*
mono_thread_info_list_head (void)
{
return &thread_list;
}
MonoThreadInfo *
mono_thread_info_attach (void)
{
MonoThreadInfo *info;
#ifdef HOST_WIN32
if (!mono_threads_inited)
{
/* This can happen from DllMain(DLL_THREAD_ATTACH) on Windows, if a
* thread is created before an embedding API user initialized Mono. */
THREADS_DEBUG ("mono_thread_info_attach called before mono_thread_info_init\n");
return NULL;
}
#endif
g_assert (mono_threads_inited);
info = (MonoThreadInfo *) mono_native_tls_get_value (thread_info_key);
if (!info) {
info = (MonoThreadInfo *) g_malloc0 (thread_info_size);
THREADS_DEBUG ("attaching %p\n", info);
if (!register_thread (info)) {
g_free (info);
return NULL;
}
}
return info;
}
void
mono_thread_info_detach (void)
{
MonoThreadInfo *info;
#ifdef HOST_WIN32
if (!mono_threads_inited)
{
/* This can happen from DllMain(THREAD_DETACH) on Windows, if a thread
* is created before an embedding API user initialized Mono. */
THREADS_DEBUG ("mono_thread_info_detach called before mono_thread_info_init\n");
return;
}
#endif
g_assert (mono_threads_inited);
info = (MonoThreadInfo *) mono_native_tls_get_value (thread_info_key);
if (info) {
THREADS_DEBUG ("detaching %p\n", info);
unregister_thread (info);
}
}
gboolean
mono_thread_info_try_get_internal_thread_gchandle (MonoThreadInfo *info, guint32 *gchandle)
{
g_assertf (info, ""); // f includes __func__
g_assert (mono_thread_info_is_current (info));
if (info->internal_thread_gchandle == G_MAXUINT32)
return FALSE;
*gchandle = info->internal_thread_gchandle;
return TRUE;
}
void
mono_thread_info_set_internal_thread_gchandle (MonoThreadInfo *info, guint32 gchandle)
{
g_assertf (info, ""); // f includes __func__
g_assert (mono_thread_info_is_current (info));
g_assert (gchandle != G_MAXUINT32);
info->internal_thread_gchandle = gchandle;
}
void
mono_thread_info_unset_internal_thread_gchandle (THREAD_INFO_TYPE *info)
{
g_assertf (info, ""); // f includes __func__
g_assert (mono_thread_info_is_current (info));
info->internal_thread_gchandle = G_MAXUINT32;
}
/*
* mono_thread_info_is_exiting:
*
* Return whenever the current thread is exiting, i.e. it is running pthread
* dtors.
*/
gboolean
mono_thread_info_is_exiting (void)
{
#if defined(__MACH__)
if (mono_native_tls_get_value (thread_exited_key) == GUINT_TO_POINTER (1))
return TRUE;
#endif
return FALSE;
}
#ifndef HOST_WIN32
static void
thread_info_key_dtor (void *arg)
{
/* Put the MonoThreadInfo back for the duration of the
* unregister code. In some circumstances the thread needs to
* take the GC lock which may block which requires a coop
* state transition. */
mono_native_tls_set_value (thread_info_key, arg);
unregister_thread (arg);
mono_native_tls_set_value (thread_info_key, NULL);
}
#endif
MonoThreadInfoFlags
mono_thread_info_get_flags (MonoThreadInfo *info)
{
return (MonoThreadInfoFlags)mono_atomic_load_i32 (&info->flags);
}
void
mono_thread_info_set_flags (MonoThreadInfoFlags flags)
{
MonoThreadInfo *info = mono_thread_info_current ();
MonoThreadInfoFlags old = (MonoThreadInfoFlags)mono_atomic_load_i32 (&info->flags);
if (threads_callbacks.thread_flags_changing)
threads_callbacks.thread_flags_changing (old, flags);
mono_atomic_store_i32 (&info->flags, flags);
if (threads_callbacks.thread_flags_changed)
threads_callbacks.thread_flags_changed (old, flags);
}
#define MONO_END_INIT_CB GINT_TO_POINTER(-1)
static GSList *init_callbacks;
void
mono_thread_info_wait_inited (void)
{
MonoSemType cb;
mono_os_sem_init (&cb, 0);
GSList *old = init_callbacks;
GSList wait_request;
wait_request.data = &cb;
wait_request.next = old;
while (mono_threads_inited != TRUE) {
GSList *old_read = (GSList*)mono_atomic_cas_ptr ((gpointer *) &init_callbacks, &wait_request, old);
// Queued up waiter, need to be unstuck
if (old_read == old) {
break;
} else if (old_read == GINT_TO_POINTER (MONO_END_INIT_CB)) {
// Is inited
return;
} else {
// We raced with another writer
wait_request.next = (GSList *) old_read;
old = old_read;
}
}
while (mono_threads_inited != TRUE) {
gboolean timedout = mono_os_sem_timedwait (&cb, 1000, MONO_SEM_FLAGS_NONE) == MONO_SEM_TIMEDWAIT_RET_TIMEDOUT;
if (!timedout)
break;
}
g_assert (mono_threads_inited);
return;
}
static void
mono_thread_info_set_inited (void)
{
mono_threads_inited = TRUE;
mono_memory_barrier ();
GSList *old = init_callbacks;
while (TRUE) {
GSList* old_read = (GSList*)mono_atomic_cas_ptr ((gpointer *) &init_callbacks, MONO_END_INIT_CB, (gpointer) old);
if (old == old_read)
break;
else
old = old_read;
}
if (old == MONO_END_INIT_CB) {
// Try not to use g_error / g_warning because this machinery used by logging
// Don't want to loop back into it.
fprintf (stderr, "Global threads inited twice");
exit (1);
return;
}
while (old != NULL) {
GSList *curr = (GSList *) old;
GSList *next = old->next;
mono_os_sem_post ((MonoSemType*)curr->data);
old = next;
}
return;
}
void
mono_thread_info_cleanup ()
{
mono_native_tls_free (thread_info_key);
mono_native_tls_free (thread_exited_key);
}
void
mono_thread_info_init (size_t info_size)
{
gboolean res;
thread_info_size = info_size;
char *sleepLimit;
mono_threads_suspend_policy_init ();
#ifdef HOST_WIN32
res = mono_native_tls_alloc (&thread_info_key, NULL);
res = mono_native_tls_alloc (&thread_exited_key, NULL);
#else
res = mono_native_tls_alloc (&thread_info_key, (void *) thread_info_key_dtor);
res = mono_native_tls_alloc (&thread_exited_key, (void *) thread_exited_dtor);
#endif
g_assert (res);
#ifndef MONO_KEYWORD_THREAD
res = mono_native_tls_alloc (&small_id_key, NULL);
#endif
g_assert (res);
if ((sleepLimit = g_getenv ("MONO_SLEEP_ABORT_LIMIT")) != NULL) {
mono_set_errno (0);
long threshold = strtol(sleepLimit, NULL, 10);
if ((errno == 0) && (threshold >= 40)) {
sleepAbortDuration = threshold;
sleepWarnDuration = threshold / 20;
} else
g_warning("MONO_SLEEP_ABORT_LIMIT must be a number >= 40");
g_free (sleepLimit);
}
mono_os_sem_init (&global_suspend_semaphore, 1);
mono_os_sem_init (&suspend_semaphore, 0);
mono_os_mutex_init (&join_mutex);
mono_lls_init (&thread_list, NULL);
mono_thread_smr_init ();
mono_threads_suspend_init ();
mono_threads_coop_init ();
mono_threads_platform_init ();
mono_thread_info_set_inited ();
g_assert (sizeof (MonoNativeThreadId) <= sizeof (uintptr_t));
}
void
mono_thread_info_callbacks_init (MonoThreadInfoCallbacks *callbacks)
{
threads_callbacks = *callbacks;
}
void
mono_thread_info_signals_init (void)
{
mono_threads_suspend_init_signals ();
}
void
mono_thread_info_runtime_init (const MonoThreadInfoRuntimeCallbacks *callbacks)
{
mono_runtime_callbacks = callbacks;
}
static gboolean
mono_thread_info_core_resume (MonoThreadInfo *info)
{
gboolean res = FALSE;
switch (mono_threads_transition_request_resume (info)) {
case ResumeError:
res = FALSE;
break;
case ResumeOk:
res = TRUE;
break;
case ResumeInitSelfResume:
resume_self_suspended (info);
res = TRUE;
break;
case ResumeInitAsyncResume:
resume_async_suspended (info);
res = TRUE;
break;
case ResumeInitBlockingResume:
resume_blocking_suspended (info);
res = TRUE;
break;
}
return res;
}
/*
* Current thread must hold the global_suspend_semaphore.
* The given MonoThreadInfo* is a suspended thread.
* Must be using hybrid suspend.
*/
static gboolean