2 * monitor.h: Monitor locking functions
5 * Dick Porter (dick@ximian.com)
10 #ifndef _MONO_METADATA_MONITOR_H_
11 #define _MONO_METADATA_MONITOR_H_
14 #include <mono/metadata/object.h>
15 #include <mono/io-layer/io-layer.h>
16 #include <mono/utils/mono-compiler.h>
17 #include <mono/utils/mono-coop-semaphore.h>
21 #define OWNER_MASK 0x0000ffff
22 #define ENTRY_COUNT_MASK 0xffff0000
23 #define ENTRY_COUNT_WAITERS 0x80000000
24 #define ENTRY_COUNT_ZERO 0x7fff0000
25 #define ENTRY_COUNT_SHIFT 16
27 struct _MonoThreadsSync
30 * The entry count field can be negative, which would mean that the entry_sem is
31 * signaled and nobody is waiting to acquire it. This can happen when the thread
32 * that was waiting is either interrupted or timeouts, and the owner releases
33 * the lock before the forementioned thread updates the entry count.
35 * The 0 entry_count value is encoded as ENTRY_COUNT_ZERO, positive numbers being
36 * greater than it and negative numbers smaller than it.
38 guint32 status; /* entry_count (16) | owner_id (16) */
40 #ifdef HAVE_MOVING_COLLECTOR
45 MonoCoopSem *entry_sem;
51 * The least significant bit stores whether a hash for the object is computed
52 * which is stored either in the lock word or in the MonoThreadsSync structure
53 * that the lock word points to.
55 * The second bit stores whether the lock word is inflated, containing an
56 * address to the MonoThreadsSync structure.
58 * If both bits are 0, either the lock word is free (entire lock word is 0)
59 * or it is a thin/flat lock.
62 * LOCK_WORD_FLAT: [owner:22 | nest:8 | status:2]
63 * LOCK_WORD_THIN_HASH: [hash:30 | status:2]
64 * LOCK_WORD_INFLATED: [sync:30 | status:2]
65 * LOCK_WORD_FAT_HASH: [sync:30 | status:2]
68 * LOCK_WORD_FLAT: [unused:22 | owner:32 | nest:8 | status:2]
69 * LOCK_WORD_THIN_HASH: [hash:62 | status:2]
70 * LOCK_WORD_INFLATED: [sync:62 | status:2]
71 * LOCK_WORD_FAT_HASH: [sync:62 | status:2]
73 * In order to save processing time and to have one additional value, the nest
74 * count starts from 0 for the lock word (just valid thread ID in the lock word
75 * means that the thread holds the lock once, although nest is 0).
76 * FIXME Have the same convention on inflated locks
80 #if SIZEOF_REGISTER == 8
82 #elif SIZEOF_REGISTER == 4
85 MonoThreadsSync *sync;
91 LOCK_WORD_HAS_HASH = 1,
92 LOCK_WORD_INFLATED = 2,
94 LOCK_WORD_STATUS_BITS = 2,
95 LOCK_WORD_NEST_BITS = 8,
97 LOCK_WORD_STATUS_MASK = (1 << LOCK_WORD_STATUS_BITS) - 1,
98 LOCK_WORD_NEST_MASK = ((1 << LOCK_WORD_NEST_BITS) - 1) << LOCK_WORD_STATUS_BITS,
100 LOCK_WORD_HASH_SHIFT = LOCK_WORD_STATUS_BITS,
101 LOCK_WORD_NEST_SHIFT = LOCK_WORD_STATUS_BITS,
102 LOCK_WORD_OWNER_SHIFT = LOCK_WORD_STATUS_BITS + LOCK_WORD_NEST_BITS
105 MONO_API void mono_locks_dump (gboolean include_untaken);
107 void mono_monitor_init (void);
108 void mono_monitor_cleanup (void);
110 gboolean mono_monitor_enter_fast (MonoObject *obj);
111 gboolean mono_monitor_enter_v4_fast (MonoObject *obj, char *lock_taken);
113 guint32 mono_monitor_get_object_monitor_gchandle (MonoObject *object);
115 void mono_monitor_threads_sync_members_offset (int *status_offset, int *nest_offset);
116 #define MONO_THREADS_SYNC_MEMBER_OFFSET(o) ((o)>>8)
117 #define MONO_THREADS_SYNC_MEMBER_SIZE(o) ((o)&0xff)
119 extern gboolean ves_icall_System_Threading_Monitor_Monitor_test_owner(MonoObject *obj);
120 extern gboolean ves_icall_System_Threading_Monitor_Monitor_test_synchronised(MonoObject *obj);
121 extern void ves_icall_System_Threading_Monitor_Monitor_pulse(MonoObject *obj);
122 extern void ves_icall_System_Threading_Monitor_Monitor_pulse_all(MonoObject *obj);
123 extern gboolean ves_icall_System_Threading_Monitor_Monitor_wait(MonoObject *obj, guint32 ms);
124 extern void ves_icall_System_Threading_Monitor_Monitor_try_enter_with_atomic_var (MonoObject *obj, guint32 ms, char *lockTaken);
128 #endif /* _MONO_METADATA_MONITOR_H_ */