/* * monitor.c: Monitor locking functions * * Author: * Dick Porter (dick@ximian.com) * * Copyright 2003 Ximian, Inc (http://www.ximian.com) * Copyright 2004-2009 Novell, Inc (http://www.novell.com) */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Pull the list of opcodes */ #define OPDEF(a,b,c,d,e,f,g,h,i,j) \ a = i, enum { #include "mono/cil/opcode.def" LAST = 0xff }; #undef OPDEF /*#define LOCK_DEBUG(a) do { a; } while (0)*/ #define LOCK_DEBUG(a) /* * The monitor implementation here is based on * http://www.usenix.org/events/jvm01/full_papers/dice/dice.pdf and * http://www.research.ibm.com/people/d/dfb/papers/Bacon98Thin.ps * * The Dice paper describes a technique for saving lock record space * by returning records to a free list when they become unused. That * sounds like unnecessary complexity to me, though if it becomes * clear that unused lock records are taking up lots of space or we * need to shave more time off by avoiding a malloc then we can always * implement the free list idea later. The timeout parameter to * try_enter voids some of the assumptions about the reference count * field in Dice's implementation too. In his version, the thread * attempting to lock a contended object will block until it succeeds, * so the reference count will never be decremented while an object is * locked. * * Bacon's thin locks have a fast path that doesn't need a lock record * for the common case of locking an unlocked or shallow-nested * object, but the technique relies on encoding the thread ID in 15 * bits (to avoid too much per-object space overhead.) Unfortunately * I don't think it's possible to reliably encode a pthread_t into 15 * bits. (The JVM implementation used seems to have a 15-bit * per-thread identifier available.) * * This implementation then combines Dice's basic lock model with * Bacon's simplification of keeping a lock record for the lifetime of * an object. */ struct _MonoThreadsSync { gsize owner; /* thread ID */ guint32 nest; #ifdef HAVE_MOVING_COLLECTOR gint32 hash_code; #endif volatile gint32 entry_count; HANDLE entry_sem; GSList *wait_list; void *data; }; typedef struct _MonitorArray MonitorArray; struct _MonitorArray { MonitorArray *next; int num_monitors; MonoThreadsSync monitors [MONO_ZERO_LEN_ARRAY]; }; #define mono_monitor_allocator_lock() EnterCriticalSection (&monitor_mutex) #define mono_monitor_allocator_unlock() LeaveCriticalSection (&monitor_mutex) static CRITICAL_SECTION monitor_mutex; static MonoThreadsSync *monitor_freelist; static MonitorArray *monitor_allocated; static int array_size = 16; #ifdef HAVE_KW_THREAD static __thread gsize tls_pthread_self MONO_TLS_FAST; #endif #ifndef HOST_WIN32 #ifdef HAVE_KW_THREAD #define GetCurrentThreadId() tls_pthread_self #else /* * The usual problem: we can't replace GetCurrentThreadId () with a macro because * it is in a public header. */ #define GetCurrentThreadId() ((gsize)pthread_self ()) #endif #endif void mono_monitor_init (void) { InitializeCriticalSection (&monitor_mutex); } void mono_monitor_cleanup (void) { MonoThreadsSync *mon; /* MonitorArray *marray, *next = NULL; */ /*DeleteCriticalSection (&monitor_mutex);*/ /* The monitors on the freelist don't have weak links - mark them */ for (mon = monitor_freelist; mon; mon = mon->data) mon->wait_list = (gpointer)-1; /* FIXME: This still crashes with sgen (async_read.exe) */ /* for (marray = monitor_allocated; marray; marray = next) { int i; for (i = 0; i < marray->num_monitors; ++i) { mon = &marray->monitors [i]; if (mon->wait_list != (gpointer)-1) mono_gc_weak_link_remove (&mon->data); } next = marray->next; g_free (marray); } */ } /* * mono_monitor_init_tls: * * Setup TLS variables used by the monitor code for the current thread. */ void mono_monitor_init_tls (void) { #if !defined(HOST_WIN32) && defined(HAVE_KW_THREAD) tls_pthread_self = (gsize) pthread_self (); #endif } static int monitor_is_on_freelist (MonoThreadsSync *mon) { MonitorArray *marray; for (marray = monitor_allocated; marray; marray = marray->next) { if (mon >= marray->monitors && mon < &marray->monitors [marray->num_monitors]) return TRUE; } return FALSE; } /** * mono_locks_dump: * @include_untaken: * * Print a report on stdout of the managed locks currently held by * threads. If @include_untaken is specified, list also inflated locks * which are unheld. * This is supposed to be used in debuggers like gdb. */ void mono_locks_dump (gboolean include_untaken) { int i; int used = 0, on_freelist = 0, to_recycle = 0, total = 0, num_arrays = 0; MonoThreadsSync *mon; MonitorArray *marray; for (mon = monitor_freelist; mon; mon = mon->data) on_freelist++; for (marray = monitor_allocated; marray; marray = marray->next) { total += marray->num_monitors; num_arrays++; for (i = 0; i < marray->num_monitors; ++i) { mon = &marray->monitors [i]; if (mon->data == NULL) { if (i < marray->num_monitors - 1) to_recycle++; } else { if (!monitor_is_on_freelist (mon->data)) { MonoObject *holder = mono_gc_weak_link_get (&mon->data); if (mon->owner) { g_print ("Lock %p in object %p held by thread %p, nest level: %d\n", mon, holder, (void*)mon->owner, mon->nest); if (mon->entry_sem) g_print ("\tWaiting on semaphore %p: %d\n", mon->entry_sem, mon->entry_count); } else if (include_untaken) { g_print ("Lock %p in object %p untaken\n", mon, holder); } used++; } } } } g_print ("Total locks (in %d array(s)): %d, used: %d, on freelist: %d, to recycle: %d\n", num_arrays, total, used, on_freelist, to_recycle); } /* LOCKING: this is called with monitor_mutex held */ static void mon_finalize (MonoThreadsSync *mon) { LOCK_DEBUG (g_message ("%s: Finalizing sync %p", __func__, mon)); if (mon->entry_sem != NULL) { CloseHandle (mon->entry_sem); mon->entry_sem = NULL; } /* If this isn't empty then something is seriously broken - it * means a thread is still waiting on the object that owned * this lock, but the object has been finalized. */ g_assert (mon->wait_list == NULL); mon->entry_count = 0; /* owner and nest are set in mon_new, no need to zero them out */ mon->data = monitor_freelist; monitor_freelist = mon; #ifndef DISABLE_PERFCOUNTERS mono_perfcounters->gc_sync_blocks--; #endif } /* LOCKING: this is called with monitor_mutex held */ static MonoThreadsSync * mon_new (gsize id) { MonoThreadsSync *new; if (!monitor_freelist) { MonitorArray *marray; int i; /* see if any sync block has been collected */ new = NULL; for (marray = monitor_allocated; marray; marray = marray->next) { for (i = 0; i < marray->num_monitors; ++i) { if (marray->monitors [i].data == NULL) { new = &marray->monitors [i]; if (new->wait_list) { /* Orphaned events left by aborted threads */ while (new->wait_list) { LOCK_DEBUG (g_message (G_GNUC_PRETTY_FUNCTION ": (%d): Closing orphaned event %d", GetCurrentThreadId (), new->wait_list->data)); CloseHandle (new->wait_list->data); new->wait_list = g_slist_remove (new->wait_list, new->wait_list->data); } } mono_gc_weak_link_remove (&new->data, FALSE); new->data = monitor_freelist; monitor_freelist = new; } } /* small perf tweak to avoid scanning all the blocks */ if (new) break; } /* need to allocate a new array of monitors */ if (!monitor_freelist) { MonitorArray *last; LOCK_DEBUG (g_message ("%s: allocating more monitors: %d", __func__, array_size)); marray = g_malloc0 (sizeof (MonoArray) + array_size * sizeof (MonoThreadsSync)); marray->num_monitors = array_size; array_size *= 2; /* link into the freelist */ for (i = 0; i < marray->num_monitors - 1; ++i) { marray->monitors [i].data = &marray->monitors [i + 1]; } marray->monitors [i].data = NULL; /* the last one */ monitor_freelist = &marray->monitors [0]; /* we happend the marray instead of prepending so that * the collecting loop above will need to scan smaller arrays first */ if (!monitor_allocated) { monitor_allocated = marray; } else { last = monitor_allocated; while (last->next) last = last->next; last->next = marray; } } } new = monitor_freelist; monitor_freelist = new->data; new->owner = id; new->nest = 1; new->data = NULL; #ifndef DISABLE_PERFCOUNTERS mono_perfcounters->gc_sync_blocks++; #endif return new; } /* * Format of the lock word: * thinhash | fathash | data * * thinhash is the lower bit: if set data is the shifted hashcode of the object. * fathash is another bit: if set the hash code is stored in the MonoThreadsSync * struct pointed to by data * if neither bit is set and data is non-NULL, data is a MonoThreadsSync */ typedef union { gsize lock_word; MonoThreadsSync *sync; } LockWord; enum { LOCK_WORD_THIN_HASH = 1, LOCK_WORD_FAT_HASH = 1 << 1, LOCK_WORD_BITS_MASK = 0x3, LOCK_WORD_HASH_SHIFT = 2 }; #define MONO_OBJECT_ALIGNMENT_SHIFT 3 /* * mono_object_hash: * @obj: an object * * Calculate a hash code for @obj that is constant while @obj is alive. */ int mono_object_hash (MonoObject* obj) { #ifdef HAVE_MOVING_COLLECTOR LockWord lw; unsigned int hash; if (!obj) return 0; lw.sync = obj->synchronisation; if (lw.lock_word & LOCK_WORD_THIN_HASH) { /*g_print ("fast thin hash %d for obj %p store\n", (unsigned int)lw.lock_word >> LOCK_WORD_HASH_SHIFT, obj);*/ return (unsigned int)lw.lock_word >> LOCK_WORD_HASH_SHIFT; } if (lw.lock_word & LOCK_WORD_FAT_HASH) { lw.lock_word &= ~LOCK_WORD_BITS_MASK; /*g_print ("fast fat hash %d for obj %p store\n", lw.sync->hash_code, obj);*/ return lw.sync->hash_code; } /* * while we are inside this function, the GC will keep this object pinned, * since we are in the unmanaged stack. Thanks to this and to the hash * function that depends only on the address, we can ignore the races if * another thread computes the hash at the same time, because it'll end up * with the same value. */ hash = (GPOINTER_TO_UINT (obj) >> MONO_OBJECT_ALIGNMENT_SHIFT) * 2654435761u; /* clear the top bits as they can be discarded */ hash &= ~(LOCK_WORD_BITS_MASK << 30); /* no hash flags were set, so it must be a MonoThreadsSync pointer if not NULL */ if (lw.sync) { lw.sync->hash_code = hash; /*g_print ("storing hash code %d for obj %p in sync %p\n", hash, obj, lw.sync);*/ lw.lock_word |= LOCK_WORD_FAT_HASH; /* this is safe since we don't deflate locks */ obj->synchronisation = lw.sync; } else { /*g_print ("storing thin hash code %d for obj %p\n", hash, obj);*/ lw.lock_word = LOCK_WORD_THIN_HASH | (hash << LOCK_WORD_HASH_SHIFT); if (InterlockedCompareExchangePointer ((gpointer*)&obj->synchronisation, lw.sync, NULL) == NULL) return hash; /*g_print ("failed store\n");*/ /* someone set the hash flag or someone inflated the object */ lw.sync = obj->synchronisation; if (lw.lock_word & LOCK_WORD_THIN_HASH) return hash; lw.lock_word &= ~LOCK_WORD_BITS_MASK; lw.sync->hash_code = hash; lw.lock_word |= LOCK_WORD_FAT_HASH; /* this is safe since we don't deflate locks */ obj->synchronisation = lw.sync; } return hash; #else /* * Wang's address-based hash function: * http://www.concentric.net/~Ttwang/tech/addrhash.htm */ return (GPOINTER_TO_UINT (obj) >> MONO_OBJECT_ALIGNMENT_SHIFT) * 2654435761u; #endif } /* If allow_interruption==TRUE, the method will be interrumped if abort or suspend * is requested. In this case it returns -1. */ static inline gint32 mono_monitor_try_enter_internal (MonoObject *obj, guint32 ms, gboolean allow_interruption) { MonoThreadsSync *mon; gsize id = GetCurrentThreadId (); HANDLE sem; guint32 then = 0, now, delta; guint32 waitms; guint32 ret; MonoInternalThread *thread; LOCK_DEBUG (g_message("%s: (%d) Trying to lock object %p (%d ms)", __func__, id, obj, ms)); if (G_UNLIKELY (!obj)) { mono_raise_exception (mono_get_exception_argument_null ("obj")); return FALSE; } retry: mon = obj->synchronisation; /* If the object has never been locked... */ if (G_UNLIKELY (mon == NULL)) { mono_monitor_allocator_lock (); mon = mon_new (id); if (InterlockedCompareExchangePointer ((gpointer*)&obj->synchronisation, mon, NULL) == NULL) { mono_gc_weak_link_add (&mon->data, obj, FALSE); mono_monitor_allocator_unlock (); /* Successfully locked */ return 1; } else { #ifdef HAVE_MOVING_COLLECTOR LockWord lw; lw.sync = obj->synchronisation; if (lw.lock_word & LOCK_WORD_THIN_HASH) { MonoThreadsSync *oldlw = lw.sync; /* move the already calculated hash */ mon->hash_code = lw.lock_word >> LOCK_WORD_HASH_SHIFT; lw.sync = mon; lw.lock_word |= LOCK_WORD_FAT_HASH; if (InterlockedCompareExchangePointer ((gpointer*)&obj->synchronisation, lw.sync, oldlw) == oldlw) { mono_gc_weak_link_add (&mon->data, obj, FALSE); mono_monitor_allocator_unlock (); /* Successfully locked */ return 1; } else { mon_finalize (mon); mono_monitor_allocator_unlock (); goto retry; } } else if (lw.lock_word & LOCK_WORD_FAT_HASH) { mon_finalize (mon); mono_monitor_allocator_unlock (); /* get the old lock without the fat hash bit */ lw.lock_word &= ~LOCK_WORD_BITS_MASK; mon = lw.sync; } else { mon_finalize (mon); mono_monitor_allocator_unlock (); mon = obj->synchronisation; } #else mon_finalize (mon); mono_monitor_allocator_unlock (); mon = obj->synchronisation; #endif } } else { #ifdef HAVE_MOVING_COLLECTOR LockWord lw; lw.sync = mon; if (lw.lock_word & LOCK_WORD_THIN_HASH) { MonoThreadsSync *oldlw = lw.sync; mono_monitor_allocator_lock (); mon = mon_new (id); /* move the already calculated hash */ mon->hash_code = lw.lock_word >> LOCK_WORD_HASH_SHIFT; lw.sync = mon; lw.lock_word |= LOCK_WORD_FAT_HASH; if (InterlockedCompareExchangePointer ((gpointer*)&obj->synchronisation, lw.sync, oldlw) == oldlw) { mono_gc_weak_link_add (&mon->data, obj, TRUE); mono_monitor_allocator_unlock (); /* Successfully locked */ return 1; } else { mon_finalize (mon); mono_monitor_allocator_unlock (); goto retry; } } #endif } #ifdef HAVE_MOVING_COLLECTOR { LockWord lw; lw.sync = mon; lw.lock_word &= ~LOCK_WORD_BITS_MASK; mon = lw.sync; } #endif /* If the object has previously been locked but isn't now... */ /* This case differs from Dice's case 3 because we don't * deflate locks or cache unused lock records */ if (G_LIKELY (mon->owner == 0)) { /* Try to install our ID in the owner field, nest * should have been left at 1 by the previous unlock * operation */ if (G_LIKELY (InterlockedCompareExchangePointer ((gpointer *)&mon->owner, (gpointer)id, 0) == 0)) { /* Success */ g_assert (mon->nest == 1); return 1; } else { /* Trumped again! */ goto retry; } } /* If the object is currently locked by this thread... */ if (mon->owner == id) { mon->nest++; return 1; } /* The object must be locked by someone else... */ #ifndef DISABLE_PERFCOUNTERS mono_perfcounters->thread_contentions++; #endif /* If ms is 0 we don't block, but just fail straight away */ if (ms == 0) { LOCK_DEBUG (g_message ("%s: (%d) timed out, returning FALSE", __func__, id)); return 0; } mono_profiler_monitor_event (obj, MONO_PROFILER_MONITOR_CONTENTION); /* The slow path begins here. */ retry_contended: /* a small amount of duplicated code, but it allows us to insert the profiler * callbacks without impacting the fast path: from here on we don't need to go back to the * retry label, but to retry_contended. At this point mon is already installed in the object * header. */ /* This case differs from Dice's case 3 because we don't * deflate locks or cache unused lock records */ if (G_LIKELY (mon->owner == 0)) { /* Try to install our ID in the owner field, nest * should have been left at 1 by the previous unlock * operation */ if (G_LIKELY (InterlockedCompareExchangePointer ((gpointer *)&mon->owner, (gpointer)id, 0) == 0)) { /* Success */ g_assert (mon->nest == 1); mono_profiler_monitor_event (obj, MONO_PROFILER_MONITOR_DONE); return 1; } } /* If the object is currently locked by this thread... */ if (mon->owner == id) { mon->nest++; mono_profiler_monitor_event (obj, MONO_PROFILER_MONITOR_DONE); return 1; } /* We need to make sure there's a semaphore handle (creating it if * necessary), and block on it */ if (mon->entry_sem == NULL) { /* Create the semaphore */ sem = CreateSemaphore (NULL, 0, 0x7fffffff, NULL); g_assert (sem != NULL); if (InterlockedCompareExchangePointer ((gpointer*)&mon->entry_sem, sem, NULL) != NULL) { /* Someone else just put a handle here */ CloseHandle (sem); } } /* If we need to time out, record a timestamp and adjust ms, * because WaitForSingleObject doesn't tell us how long it * waited for. * * Don't block forever here, because theres a chance the owner * thread released the lock while we were creating the * semaphore: we would not get the wakeup. Using the event * handle technique from pulse/wait would involve locking the * lock struct and therefore slowing down the fast path. */ if (ms != INFINITE) { then = mono_msec_ticks (); if (ms < 100) { waitms = ms; } else { waitms = 100; } } else { waitms = 100; } InterlockedIncrement (&mon->entry_count); #ifndef DISABLE_PERFCOUNTERS mono_perfcounters->thread_queue_len++; mono_perfcounters->thread_queue_max++; #endif thread = mono_thread_internal_current (); mono_thread_set_state (thread, ThreadState_WaitSleepJoin); /* * We pass TRUE instead of allow_interruption since we have to check for the * StopRequested case below. */ ret = WaitForSingleObjectEx (mon->entry_sem, waitms, TRUE); mono_thread_clr_state (thread, ThreadState_WaitSleepJoin); InterlockedDecrement (&mon->entry_count); #ifndef DISABLE_PERFCOUNTERS mono_perfcounters->thread_queue_len--; #endif if (ms != INFINITE) { now = mono_msec_ticks (); if (now < then) { /* The counter must have wrapped around */ LOCK_DEBUG (g_message ("%s: wrapped around! now=0x%x then=0x%x", __func__, now, then)); now += (0xffffffff - then); then = 0; LOCK_DEBUG (g_message ("%s: wrap rejig: now=0x%x then=0x%x delta=0x%x", __func__, now, then, now-then)); } delta = now - then; if (delta >= ms) { ms = 0; } else { ms -= delta; } if ((ret == WAIT_TIMEOUT || (ret == WAIT_IO_COMPLETION && !allow_interruption)) && ms > 0) { /* More time left */ goto retry_contended; } } else { if (ret == WAIT_TIMEOUT || (ret == WAIT_IO_COMPLETION && !allow_interruption)) { if (ret == WAIT_IO_COMPLETION && (mono_thread_test_state (mono_thread_internal_current (), (ThreadState_StopRequested|ThreadState_SuspendRequested)))) { /* * We have to obey a stop/suspend request even if * allow_interruption is FALSE to avoid hangs at shutdown. */ mono_profiler_monitor_event (obj, MONO_PROFILER_MONITOR_FAIL); return -1; } /* Infinite wait, so just try again */ goto retry_contended; } } if (ret == WAIT_OBJECT_0) { /* retry from the top */ goto retry_contended; } /* We must have timed out */ LOCK_DEBUG (g_message ("%s: (%d) timed out waiting, returning FALSE", __func__, id)); mono_profiler_monitor_event (obj, MONO_PROFILER_MONITOR_FAIL); if (ret == WAIT_IO_COMPLETION) return -1; else return 0; } gboolean mono_monitor_enter (MonoObject *obj) { return mono_monitor_try_enter_internal (obj, INFINITE, FALSE) == 1; } gboolean mono_monitor_try_enter (MonoObject *obj, guint32 ms) { return mono_monitor_try_enter_internal (obj, ms, FALSE) == 1; } void mono_monitor_exit (MonoObject *obj) { MonoThreadsSync *mon; guint32 nest; LOCK_DEBUG (g_message ("%s: (%d) Unlocking %p", __func__, GetCurrentThreadId (), obj)); if (G_UNLIKELY (!obj)) { mono_raise_exception (mono_get_exception_argument_null ("obj")); return; } mon = obj->synchronisation; #ifdef HAVE_MOVING_COLLECTOR { LockWord lw; lw.sync = mon; if (lw.lock_word & LOCK_WORD_THIN_HASH) return; lw.lock_word &= ~LOCK_WORD_BITS_MASK; mon = lw.sync; } #endif if (G_UNLIKELY (mon == NULL)) { /* No one ever used Enter. Just ignore the Exit request as MS does */ return; } if (G_UNLIKELY (mon->owner != GetCurrentThreadId ())) { return; } nest = mon->nest - 1; if (nest == 0) { LOCK_DEBUG (g_message ("%s: (%d) Object %p is now unlocked", __func__, GetCurrentThreadId (), obj)); /* object is now unlocked, leave nest==1 so we don't * need to set it when the lock is reacquired */ mon->owner = 0; /* Do the wakeup stuff. It's possible that the last * blocking thread gave up waiting just before we * release the semaphore resulting in a futile wakeup * next time there's contention for this object, but * it means we don't have to waste time locking the * struct. */ if (mon->entry_count > 0) { ReleaseSemaphore (mon->entry_sem, 1, NULL); } } else { LOCK_DEBUG (g_message ("%s: (%d) Object %p is now locked %d times", __func__, GetCurrentThreadId (), obj, nest)); mon->nest = nest; } } void** mono_monitor_get_object_monitor_weak_link (MonoObject *object) { LockWord lw; MonoThreadsSync *sync = NULL; lw.sync = object->synchronisation; if (lw.lock_word & LOCK_WORD_FAT_HASH) { lw.lock_word &= ~LOCK_WORD_BITS_MASK; sync = lw.sync; } else if (!(lw.lock_word & LOCK_WORD_THIN_HASH)) { sync = lw.sync; } if (sync && sync->data) return &sync->data; return NULL; } #ifndef DISABLE_JIT static void emit_obj_syncp_check (MonoMethodBuilder *mb, int syncp_loc, int *obj_null_branch, int *true_locktaken_branch, int *syncp_true_false_branch, int *thin_hash_branch, gboolean branch_on_true) { /* ldarg 0 obj brfalse.s obj_null */ mono_mb_emit_byte (mb, CEE_LDARG_0); *obj_null_branch = mono_mb_emit_short_branch (mb, CEE_BRFALSE_S); /* ldarg.1 ldind.i1 brtrue.s true_locktaken */ if (true_locktaken_branch) { mono_mb_emit_byte (mb, CEE_LDARG_1); mono_mb_emit_byte (mb, CEE_LDIND_I1); *true_locktaken_branch = mono_mb_emit_short_branch (mb, CEE_BRTRUE_S); } /* ldarg 0 obj conv.i objp ldc.i4 G_STRUCT_OFFSET(MonoObject, synchronisation) objp off add &syncp ldind.i syncp stloc syncp ldloc syncp syncp brtrue/false.s syncp_true_false */ mono_mb_emit_byte (mb, CEE_LDARG_0); mono_mb_emit_byte (mb, CEE_CONV_I); mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoObject, synchronisation)); mono_mb_emit_byte (mb, CEE_ADD); mono_mb_emit_byte (mb, CEE_LDIND_I); mono_mb_emit_stloc (mb, syncp_loc); if (mono_gc_is_moving ()) { /*check for a thin hash*/ mono_mb_emit_ldloc (mb, syncp_loc); mono_mb_emit_icon (mb, 0x01); mono_mb_emit_byte (mb, CEE_CONV_I); mono_mb_emit_byte (mb, CEE_AND); *thin_hash_branch = mono_mb_emit_short_branch (mb, CEE_BRTRUE_S); /*clear gc bits*/ mono_mb_emit_ldloc (mb, syncp_loc); mono_mb_emit_icon (mb, ~0x3); mono_mb_emit_byte (mb, CEE_CONV_I); mono_mb_emit_byte (mb, CEE_AND); mono_mb_emit_stloc (mb, syncp_loc); } else { *thin_hash_branch = 0; } mono_mb_emit_ldloc (mb, syncp_loc); *syncp_true_false_branch = mono_mb_emit_short_branch (mb, branch_on_true ? CEE_BRTRUE_S : CEE_BRFALSE_S); } #endif static MonoMethod* monitor_il_fastpaths[3]; gboolean mono_monitor_is_il_fastpath_wrapper (MonoMethod *method) { int i; for (i = 0; i < 3; ++i) { if (monitor_il_fastpaths [i] == method) return TRUE; } return FALSE; } enum { FASTPATH_ENTER, FASTPATH_ENTERV4, FASTPATH_EXIT }; static MonoMethod* register_fastpath (MonoMethod *method, int idx) { mono_memory_barrier (); monitor_il_fastpaths [idx] = method; return method; } static MonoMethod* mono_monitor_get_fast_enter_method (MonoMethod *monitor_enter_method) { MonoMethodBuilder *mb; MonoMethod *res; static MonoMethod *compare_exchange_method; int obj_null_branch, true_locktaken_branch = 0, syncp_null_branch, has_owner_branch, other_owner_branch, tid_branch, thin_hash_branch; int tid_loc, syncp_loc, owner_loc; int thread_tls_offset; gboolean is_v4 = mono_method_signature (monitor_enter_method)->param_count == 2; int fast_path_idx = is_v4 ? FASTPATH_ENTERV4 : FASTPATH_ENTER; WrapperInfo *info; /* The !is_v4 version is not used/tested */ g_assert (is_v4); thread_tls_offset = mono_thread_get_tls_offset (); if (thread_tls_offset == -1) return NULL; if (monitor_il_fastpaths [fast_path_idx]) return monitor_il_fastpaths [fast_path_idx]; if (!compare_exchange_method) { MonoMethodDesc *desc; MonoClass *class; desc = mono_method_desc_new ("Interlocked:CompareExchange(intptr&,intptr,intptr)", FALSE); class = mono_class_from_name (mono_defaults.corlib, "System.Threading", "Interlocked"); compare_exchange_method = mono_method_desc_search_in_class (desc, class); mono_method_desc_free (desc); if (!compare_exchange_method) return NULL; } mb = mono_mb_new (mono_defaults.monitor_class, is_v4 ? "FastMonitorEnterV4" : "FastMonitorEnter", MONO_WRAPPER_UNKNOWN); mb->method->slot = -1; mb->method->flags = METHOD_ATTRIBUTE_PUBLIC | METHOD_ATTRIBUTE_STATIC | METHOD_ATTRIBUTE_HIDE_BY_SIG | METHOD_ATTRIBUTE_FINAL; #ifndef DISABLE_JIT tid_loc = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg); syncp_loc = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg); owner_loc = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg); emit_obj_syncp_check (mb, syncp_loc, &obj_null_branch, is_v4 ? &true_locktaken_branch : NULL, &syncp_null_branch, &thin_hash_branch, FALSE); /* mono. tls thread_tls_offset threadp ldc.i4 G_STRUCT_OFFSET(MonoThread, tid) threadp off add &tid ldind.i tid stloc tid ldloc syncp syncp ldc.i4 G_STRUCT_OFFSET(MonoThreadsSync, owner) syncp off add &owner ldind.i owner stloc owner ldloc owner owner brtrue.s tid */ mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX); mono_mb_emit_byte (mb, CEE_MONO_TLS); mono_mb_emit_i4 (mb, TLS_KEY_THREAD); mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoInternalThread, tid)); mono_mb_emit_byte (mb, CEE_ADD); mono_mb_emit_byte (mb, CEE_LDIND_I); mono_mb_emit_stloc (mb, tid_loc); mono_mb_emit_ldloc (mb, syncp_loc); mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoThreadsSync, owner)); mono_mb_emit_byte (mb, CEE_ADD); mono_mb_emit_byte (mb, CEE_LDIND_I); mono_mb_emit_stloc (mb, owner_loc); mono_mb_emit_ldloc (mb, owner_loc); tid_branch = mono_mb_emit_short_branch (mb, CEE_BRTRUE_S); /* ldloc syncp syncp ldc.i4 G_STRUCT_OFFSET(MonoThreadsSync, owner) syncp off add &owner ldloc tid &owner tid ldc.i4 0 &owner tid 0 call System.Threading.Interlocked.CompareExchange oldowner brtrue.s has_owner ret */ mono_mb_emit_ldloc (mb, syncp_loc); mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoThreadsSync, owner)); mono_mb_emit_byte (mb, CEE_ADD); mono_mb_emit_ldloc (mb, tid_loc); mono_mb_emit_byte (mb, CEE_LDC_I4_0); mono_mb_emit_managed_call (mb, compare_exchange_method, NULL); has_owner_branch = mono_mb_emit_short_branch (mb, CEE_BRTRUE_S); if (is_v4) { mono_mb_emit_byte (mb, CEE_LDARG_1); mono_mb_emit_byte (mb, CEE_LDC_I4_1); mono_mb_emit_byte (mb, CEE_STIND_I1); } mono_mb_emit_byte (mb, CEE_RET); /* tid: ldloc owner owner ldloc tid owner tid brne.s other_owner ldloc syncp syncp ldc.i4 G_STRUCT_OFFSET(MonoThreadsSync, nest) syncp off add &nest dup &nest &nest ldind.i4 &nest nest ldc.i4 1 &nest nest 1 add &nest nest+ stind.i4 ret */ mono_mb_patch_short_branch (mb, tid_branch); mono_mb_emit_ldloc (mb, owner_loc); mono_mb_emit_ldloc (mb, tid_loc); other_owner_branch = mono_mb_emit_short_branch (mb, CEE_BNE_UN_S); mono_mb_emit_ldloc (mb, syncp_loc); mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoThreadsSync, nest)); mono_mb_emit_byte (mb, CEE_ADD); mono_mb_emit_byte (mb, CEE_DUP); mono_mb_emit_byte (mb, CEE_LDIND_I4); mono_mb_emit_byte (mb, CEE_LDC_I4_1); mono_mb_emit_byte (mb, CEE_ADD); mono_mb_emit_byte (mb, CEE_STIND_I4); if (is_v4) { mono_mb_emit_byte (mb, CEE_LDARG_1); mono_mb_emit_byte (mb, CEE_LDC_I4_1); mono_mb_emit_byte (mb, CEE_STIND_I1); } mono_mb_emit_byte (mb, CEE_RET); /* obj_null, syncp_null, has_owner, other_owner: ldarg 0 obj call System.Threading.Monitor.Enter ret */ if (thin_hash_branch) mono_mb_patch_short_branch (mb, thin_hash_branch); mono_mb_patch_short_branch (mb, obj_null_branch); mono_mb_patch_short_branch (mb, syncp_null_branch); mono_mb_patch_short_branch (mb, has_owner_branch); mono_mb_patch_short_branch (mb, other_owner_branch); if (true_locktaken_branch) mono_mb_patch_short_branch (mb, true_locktaken_branch); mono_mb_emit_byte (mb, CEE_LDARG_0); if (is_v4) mono_mb_emit_byte (mb, CEE_LDARG_1); mono_mb_emit_managed_call (mb, monitor_enter_method, NULL); mono_mb_emit_byte (mb, CEE_RET); #endif res = register_fastpath (mono_mb_create_method (mb, mono_signature_no_pinvoke (monitor_enter_method), 5), fast_path_idx); info = mono_image_alloc0 (mono_defaults.corlib, sizeof (WrapperInfo)); info->subtype = is_v4 ? WRAPPER_SUBTYPE_FAST_MONITOR_ENTER_V4 : WRAPPER_SUBTYPE_FAST_MONITOR_ENTER; mono_marshal_set_wrapper_info (res, info); mono_mb_free (mb); return res; } static MonoMethod* mono_monitor_get_fast_exit_method (MonoMethod *monitor_exit_method) { MonoMethodBuilder *mb; MonoMethod *res; int obj_null_branch, has_waiting_branch, has_syncp_branch, owned_branch, nested_branch, thin_hash_branch; int thread_tls_offset; int syncp_loc; WrapperInfo *info; thread_tls_offset = mono_thread_get_tls_offset (); if (thread_tls_offset == -1) return NULL; if (monitor_il_fastpaths [FASTPATH_EXIT]) return monitor_il_fastpaths [FASTPATH_EXIT]; mb = mono_mb_new (mono_defaults.monitor_class, "FastMonitorExit", MONO_WRAPPER_UNKNOWN); mb->method->slot = -1; mb->method->flags = METHOD_ATTRIBUTE_PUBLIC | METHOD_ATTRIBUTE_STATIC | METHOD_ATTRIBUTE_HIDE_BY_SIG | METHOD_ATTRIBUTE_FINAL; #ifndef DISABLE_JIT syncp_loc = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg); emit_obj_syncp_check (mb, syncp_loc, &obj_null_branch, NULL, &has_syncp_branch, &thin_hash_branch, TRUE); /* ret */ mono_mb_emit_byte (mb, CEE_RET); /* has_syncp: ldloc syncp syncp ldc.i4 G_STRUCT_OFFSET(MonoThreadsSync, owner) syncp off add &owner ldind.i owner mono. tls thread_tls_offset owner threadp ldc.i4 G_STRUCT_OFFSET(MonoThread, tid) owner threadp off add owner &tid ldind.i owner tid beq.s owned */ mono_mb_patch_short_branch (mb, has_syncp_branch); mono_mb_emit_ldloc (mb, syncp_loc); mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoThreadsSync, owner)); mono_mb_emit_byte (mb, CEE_ADD); mono_mb_emit_byte (mb, CEE_LDIND_I); mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX); mono_mb_emit_byte (mb, CEE_MONO_TLS); mono_mb_emit_i4 (mb, TLS_KEY_THREAD); mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoInternalThread, tid)); mono_mb_emit_byte (mb, CEE_ADD); mono_mb_emit_byte (mb, CEE_LDIND_I); owned_branch = mono_mb_emit_short_branch (mb, CEE_BEQ_S); /* ret */ mono_mb_emit_byte (mb, CEE_RET); /* owned: ldloc syncp syncp ldc.i4 G_STRUCT_OFFSET(MonoThreadsSync, nest) syncp off add &nest dup &nest &nest ldind.i4 &nest nest dup &nest nest nest ldc.i4 1 &nest nest nest 1 bgt.un.s nested &nest nest */ mono_mb_patch_short_branch (mb, owned_branch); mono_mb_emit_ldloc (mb, syncp_loc); mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoThreadsSync, nest)); mono_mb_emit_byte (mb, CEE_ADD); mono_mb_emit_byte (mb, CEE_DUP); mono_mb_emit_byte (mb, CEE_LDIND_I4); mono_mb_emit_byte (mb, CEE_DUP); mono_mb_emit_byte (mb, CEE_LDC_I4_1); nested_branch = mono_mb_emit_short_branch (mb, CEE_BGT_UN_S); /* pop &nest pop ldloc syncp syncp ldc.i4 G_STRUCT_OFFSET(MonoThreadsSync, entry_count) syncp off add &count ldind.i4 count brtrue.s has_waiting */ mono_mb_emit_byte (mb, CEE_POP); mono_mb_emit_byte (mb, CEE_POP); mono_mb_emit_ldloc (mb, syncp_loc); mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoThreadsSync, entry_count)); mono_mb_emit_byte (mb, CEE_ADD); mono_mb_emit_byte (mb, CEE_LDIND_I4); has_waiting_branch = mono_mb_emit_short_branch (mb, CEE_BRTRUE_S); /* ldloc syncp syncp ldc.i4 G_STRUCT_OFFSET(MonoThreadsSync, owner) syncp off add &owner ldnull &owner 0 stind.i ret */ mono_mb_emit_ldloc (mb, syncp_loc); mono_mb_emit_icon (mb, G_STRUCT_OFFSET (MonoThreadsSync, owner)); mono_mb_emit_byte (mb, CEE_ADD); mono_mb_emit_byte (mb, CEE_LDNULL); mono_mb_emit_byte (mb, CEE_STIND_I); mono_mb_emit_byte (mb, CEE_RET); /* nested: ldc.i4 1 &nest nest 1 sub &nest nest- stind.i4 ret */ mono_mb_patch_short_branch (mb, nested_branch); mono_mb_emit_byte (mb, CEE_LDC_I4_1); mono_mb_emit_byte (mb, CEE_SUB); mono_mb_emit_byte (mb, CEE_STIND_I4); mono_mb_emit_byte (mb, CEE_RET); /* obj_null, has_waiting: ldarg 0 obj call System.Threading.Monitor.Exit ret */ if (thin_hash_branch) mono_mb_patch_short_branch (mb, thin_hash_branch); mono_mb_patch_short_branch (mb, obj_null_branch); mono_mb_patch_short_branch (mb, has_waiting_branch); mono_mb_emit_byte (mb, CEE_LDARG_0); mono_mb_emit_managed_call (mb, monitor_exit_method, NULL); mono_mb_emit_byte (mb, CEE_RET); #endif res = register_fastpath (mono_mb_create_method (mb, mono_signature_no_pinvoke (monitor_exit_method), 5), FASTPATH_EXIT); mono_mb_free (mb); info = mono_image_alloc0 (mono_defaults.corlib, sizeof (WrapperInfo)); info->subtype = WRAPPER_SUBTYPE_FAST_MONITOR_EXIT; mono_marshal_set_wrapper_info (res, info); return res; } MonoMethod* mono_monitor_get_fast_path (MonoMethod *enter_or_exit) { if (strcmp (enter_or_exit->name, "Enter") == 0) return mono_monitor_get_fast_enter_method (enter_or_exit); if (strcmp (enter_or_exit->name, "Exit") == 0) return mono_monitor_get_fast_exit_method (enter_or_exit); g_assert_not_reached (); return NULL; } /* * mono_monitor_threads_sync_member_offset: * @owner_offset: returns size and offset of the "owner" member * @nest_offset: returns size and offset of the "nest" member * @entry_count_offset: returns size and offset of the "entry_count" member * * Returns the offsets and sizes of three members of the * MonoThreadsSync struct. The Monitor ASM fastpaths need this. */ void mono_monitor_threads_sync_members_offset (int *owner_offset, int *nest_offset, int *entry_count_offset) { MonoThreadsSync ts; #define ENCODE_OFF_SIZE(o,s) (((o) << 8) | ((s) & 0xff)) *owner_offset = ENCODE_OFF_SIZE (G_STRUCT_OFFSET (MonoThreadsSync, owner), sizeof (ts.owner)); *nest_offset = ENCODE_OFF_SIZE (G_STRUCT_OFFSET (MonoThreadsSync, nest), sizeof (ts.nest)); *entry_count_offset = ENCODE_OFF_SIZE (G_STRUCT_OFFSET (MonoThreadsSync, entry_count), sizeof (ts.entry_count)); } gboolean ves_icall_System_Threading_Monitor_Monitor_try_enter (MonoObject *obj, guint32 ms) { gint32 res; do { res = mono_monitor_try_enter_internal (obj, ms, TRUE); if (res == -1) mono_thread_interruption_checkpoint (); } while (res == -1); return res == 1; } void ves_icall_System_Threading_Monitor_Monitor_try_enter_with_atomic_var (MonoObject *obj, guint32 ms, char *lockTaken) { gint32 res; do { res = mono_monitor_try_enter_internal (obj, ms, TRUE); /*This means we got interrupted during the wait and didn't got the monitor.*/ if (res == -1) mono_thread_interruption_checkpoint (); } while (res == -1); /*It's safe to do it from here since interruption would happen only on the wrapper.*/ *lockTaken = res == 1; } gboolean ves_icall_System_Threading_Monitor_Monitor_test_owner (MonoObject *obj) { MonoThreadsSync *mon; LOCK_DEBUG (g_message ("%s: Testing if %p is owned by thread %d", __func__, obj, GetCurrentThreadId())); mon = obj->synchronisation; #ifdef HAVE_MOVING_COLLECTOR { LockWord lw; lw.sync = mon; if (lw.lock_word & LOCK_WORD_THIN_HASH) return FALSE; lw.lock_word &= ~LOCK_WORD_BITS_MASK; mon = lw.sync; } #endif if (mon == NULL) { return FALSE; } if(mon->owner==GetCurrentThreadId ()) { return(TRUE); } return(FALSE); } gboolean ves_icall_System_Threading_Monitor_Monitor_test_synchronised (MonoObject *obj) { MonoThreadsSync *mon; LOCK_DEBUG (g_message("%s: (%d) Testing if %p is owned by any thread", __func__, GetCurrentThreadId (), obj)); mon = obj->synchronisation; #ifdef HAVE_MOVING_COLLECTOR { LockWord lw; lw.sync = mon; if (lw.lock_word & LOCK_WORD_THIN_HASH) return FALSE; lw.lock_word &= ~LOCK_WORD_BITS_MASK; mon = lw.sync; } #endif if (mon == NULL) { return FALSE; } if (mon->owner != 0) { return TRUE; } return FALSE; } /* All wait list manipulation in the pulse, pulseall and wait * functions happens while the monitor lock is held, so we don't need * any extra struct locking */ void ves_icall_System_Threading_Monitor_Monitor_pulse (MonoObject *obj) { MonoThreadsSync *mon; LOCK_DEBUG (g_message ("%s: (%d) Pulsing %p", __func__, GetCurrentThreadId (), obj)); mon = obj->synchronisation; #ifdef HAVE_MOVING_COLLECTOR { LockWord lw; lw.sync = mon; if (lw.lock_word & LOCK_WORD_THIN_HASH) { mono_raise_exception (mono_get_exception_synchronization_lock ("Not locked")); return; } lw.lock_word &= ~LOCK_WORD_BITS_MASK; mon = lw.sync; } #endif if (mon == NULL) { mono_raise_exception (mono_get_exception_synchronization_lock ("Not locked")); return; } if (mon->owner != GetCurrentThreadId ()) { mono_raise_exception (mono_get_exception_synchronization_lock ("Not locked by this thread")); return; } LOCK_DEBUG (g_message ("%s: (%d) %d threads waiting", __func__, GetCurrentThreadId (), g_slist_length (mon->wait_list))); if (mon->wait_list != NULL) { LOCK_DEBUG (g_message ("%s: (%d) signalling and dequeuing handle %p", __func__, GetCurrentThreadId (), mon->wait_list->data)); SetEvent (mon->wait_list->data); mon->wait_list = g_slist_remove (mon->wait_list, mon->wait_list->data); } } void ves_icall_System_Threading_Monitor_Monitor_pulse_all (MonoObject *obj) { MonoThreadsSync *mon; LOCK_DEBUG (g_message("%s: (%d) Pulsing all %p", __func__, GetCurrentThreadId (), obj)); mon = obj->synchronisation; #ifdef HAVE_MOVING_COLLECTOR { LockWord lw; lw.sync = mon; if (lw.lock_word & LOCK_WORD_THIN_HASH) { mono_raise_exception (mono_get_exception_synchronization_lock ("Not locked")); return; } lw.lock_word &= ~LOCK_WORD_BITS_MASK; mon = lw.sync; } #endif if (mon == NULL) { mono_raise_exception (mono_get_exception_synchronization_lock ("Not locked")); return; } if (mon->owner != GetCurrentThreadId ()) { mono_raise_exception (mono_get_exception_synchronization_lock ("Not locked by this thread")); return; } LOCK_DEBUG (g_message ("%s: (%d) %d threads waiting", __func__, GetCurrentThreadId (), g_slist_length (mon->wait_list))); while (mon->wait_list != NULL) { LOCK_DEBUG (g_message ("%s: (%d) signalling and dequeuing handle %p", __func__, GetCurrentThreadId (), mon->wait_list->data)); SetEvent (mon->wait_list->data); mon->wait_list = g_slist_remove (mon->wait_list, mon->wait_list->data); } } gboolean ves_icall_System_Threading_Monitor_Monitor_wait (MonoObject *obj, guint32 ms) { MonoThreadsSync *mon; HANDLE event; guint32 nest; guint32 ret; gboolean success = FALSE; gint32 regain; MonoInternalThread *thread = mono_thread_internal_current (); LOCK_DEBUG (g_message ("%s: (%d) Trying to wait for %p with timeout %dms", __func__, GetCurrentThreadId (), obj, ms)); mon = obj->synchronisation; #ifdef HAVE_MOVING_COLLECTOR { LockWord lw; lw.sync = mon; if (lw.lock_word & LOCK_WORD_THIN_HASH) { mono_raise_exception (mono_get_exception_synchronization_lock ("Not locked")); return FALSE; } lw.lock_word &= ~LOCK_WORD_BITS_MASK; mon = lw.sync; } #endif if (mon == NULL) { mono_raise_exception (mono_get_exception_synchronization_lock ("Not locked")); return FALSE; } if (mon->owner != GetCurrentThreadId ()) { mono_raise_exception (mono_get_exception_synchronization_lock ("Not locked by this thread")); return FALSE; } /* Do this WaitSleepJoin check before creating the event handle */ mono_thread_current_check_pending_interrupt (); event = CreateEvent (NULL, FALSE, FALSE, NULL); if (event == NULL) { mono_raise_exception (mono_get_exception_synchronization_lock ("Failed to set up wait event")); return FALSE; } LOCK_DEBUG (g_message ("%s: (%d) queuing handle %p", __func__, GetCurrentThreadId (), event)); mono_thread_current_check_pending_interrupt (); mono_thread_set_state (thread, ThreadState_WaitSleepJoin); mon->wait_list = g_slist_append (mon->wait_list, event); /* Save the nest count, and release the lock */ nest = mon->nest; mon->nest = 1; mono_monitor_exit (obj); LOCK_DEBUG (g_message ("%s: (%d) Unlocked %p lock %p", __func__, GetCurrentThreadId (), obj, mon)); /* There's no race between unlocking mon and waiting for the * event, because auto reset events are sticky, and this event * is private to this thread. Therefore even if the event was * signalled before we wait, we still succeed. */ ret = WaitForSingleObjectEx (event, ms, TRUE); /* Reset the thread state fairly early, so we don't have to worry * about the monitor error checking */ mono_thread_clr_state (thread, ThreadState_WaitSleepJoin); if (mono_thread_interruption_requested ()) { /* * Can't remove the event from wait_list, since the monitor is not locked by * us. So leave it there, mon_new () will delete it when the mon structure * is placed on the free list. * FIXME: The caller expects to hold the lock after the wait returns, but it * doesn't happen in this case: * http://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=97268 */ return FALSE; } /* Regain the lock with the previous nest count */ do { regain = mono_monitor_try_enter_internal (obj, INFINITE, TRUE); if (regain == -1) mono_thread_interruption_checkpoint (); } while (regain == -1); if (regain == 0) { /* Something went wrong, so throw a * SynchronizationLockException */ CloseHandle (event); mono_raise_exception (mono_get_exception_synchronization_lock ("Failed to regain lock")); return FALSE; } mon->nest = nest; LOCK_DEBUG (g_message ("%s: (%d) Regained %p lock %p", __func__, GetCurrentThreadId (), obj, mon)); if (ret == WAIT_TIMEOUT) { /* Poll the event again, just in case it was signalled * while we were trying to regain the monitor lock */ ret = WaitForSingleObjectEx (event, 0, FALSE); } /* Pulse will have popped our event from the queue if it signalled * us, so we only do it here if the wait timed out. * * This avoids a race condition where the thread holding the * lock can Pulse several times before the WaitForSingleObject * returns. If we popped the queue here then this event might * be signalled more than once, thereby starving another * thread. */ if (ret == WAIT_OBJECT_0) { LOCK_DEBUG (g_message ("%s: (%d) Success", __func__, GetCurrentThreadId ())); success = TRUE; } else { LOCK_DEBUG (g_message ("%s: (%d) Wait failed, dequeuing handle %p", __func__, GetCurrentThreadId (), event)); /* No pulse, so we have to remove ourself from the * wait queue */ mon->wait_list = g_slist_remove (mon->wait_list, event); } CloseHandle (event); return success; }