/mono/metadata/monitor.c
C | 1554 lines | 971 code | 199 blank | 384 comment | 205 complexity | ffce6f6a0e4c8f2fa32f5de12ae3ef6d MD5 | raw file
Possible License(s): Unlicense, Apache-2.0, LGPL-2.0, MPL-2.0-no-copyleft-exception, CC-BY-SA-3.0, GPL-2.0
- /*
- * 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 <config.h>
- #include <glib.h>
- #include <string.h>
- #include <mono/metadata/monitor.h>
- #include <mono/metadata/threads-types.h>
- #include <mono/metadata/exception.h>
- #include <mono/metadata/threads.h>
- #include <mono/io-layer/io-layer.h>
- #include <mono/metadata/object-internals.h>
- #include <mono/metadata/class-internals.h>
- #include <mono/metadata/gc-internal.h>
- #include <mono/metadata/method-builder.h>
- #include <mono/metadata/debug-helpers.h>
- #include <mono/metadata/tabledefs.h>
- #include <mono/metadata/marshal.h>
- #include <mono/metadata/profiler-private.h>
- #include <mono/utils/mono-time.h>
- /*
- * 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 = 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, thread_tls_offset);
- 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, thread_tls_offset);
- 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;
- }