1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
|
diff -ru ../../work.orig/linuxthreads-2.2.3_1/condvar.c ./condvar.c
--- ../../work.orig/linuxthreads-2.2.3_1/condvar.c Thu Apr 12 21:02:02 2001
+++ ./condvar.c Wed Jul 18 13:30:47 2001
@@ -55,6 +55,8 @@
return did_remove;
}
+extern int __pthread_mutex_condwait_completelock(pthread_mutex_t *mutex);
+
int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
{
volatile pthread_descr self = thread_self();
@@ -74,6 +76,7 @@
/* Register extrication interface */
THREAD_SETMEM(self, p_condvar_avail, 0);
+ THREAD_SETMEM(self, p_condwait_mutex, mutex);
__pthread_set_own_extricate_if(self, &extr);
/* Atomically enqueue thread for waiting, but only if it is not
@@ -121,15 +124,35 @@
if (THREAD_GETMEM(self, p_woken_by_cancel)
&& THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) {
THREAD_SETMEM(self, p_woken_by_cancel, 0);
- pthread_mutex_lock(mutex);
+ if (THREAD_GETMEM(self, p_condwait_mutex) == NULL) {
+ if (THREAD_GETMEM(self, p_condwait_extra_restart) != 0) {
+ if (spurious_wakeup_count > 0)
+ spurious_wakeup_count--;
+ else
+ suspend(self);
+ }
+ __pthread_mutex_condwait_completelock(mutex);
+ } else
+ pthread_mutex_lock(mutex);
__pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME);
}
+ if (THREAD_GETMEM(self, p_condwait_mutex) == NULL &&
+ THREAD_GETMEM(self, p_condwait_extra_restart) != 0) {
+ if (spurious_wakeup_count > 0)
+ spurious_wakeup_count--;
+ else
+ suspend(self);
+ }
+
/* Put back any resumes we caught that don't belong to us. */
while (spurious_wakeup_count--)
restart(self);
- pthread_mutex_lock(mutex);
+ if (THREAD_GETMEM(self, p_condwait_mutex) == NULL)
+ __pthread_mutex_condwait_completelock(mutex);
+ else
+ pthread_mutex_lock(mutex);
return 0;
}
@@ -155,6 +178,7 @@
/* Register extrication interface */
THREAD_SETMEM(self, p_condvar_avail, 0);
+ THREAD_SETMEM(self, p_condwait_mutex, mutex);
__pthread_set_own_extricate_if(self, &extr);
/* Enqueue to wait on the condition and check for cancellation. */
@@ -215,15 +239,35 @@
if (THREAD_GETMEM(self, p_woken_by_cancel)
&& THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) {
THREAD_SETMEM(self, p_woken_by_cancel, 0);
- pthread_mutex_lock(mutex);
+ if (THREAD_GETMEM(self, p_condwait_mutex) == NULL) {
+ if (THREAD_GETMEM(self, p_condwait_extra_restart) != 0) {
+ if (spurious_wakeup_count > 0)
+ spurious_wakeup_count--;
+ else
+ suspend(self);
+ }
+ __pthread_mutex_condwait_completelock(mutex);
+ } else
+ pthread_mutex_lock(mutex);
__pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME);
}
+ if (THREAD_GETMEM(self, p_condwait_mutex) == NULL &&
+ THREAD_GETMEM(self, p_condwait_extra_restart) != 0) {
+ if (spurious_wakeup_count > 0)
+ spurious_wakeup_count--;
+ else
+ suspend(self);
+ }
+
/* Put back any resumes we caught that don't belong to us. */
while (spurious_wakeup_count--)
restart(self);
- pthread_mutex_lock(mutex);
+ if (THREAD_GETMEM(self, p_condwait_mutex) == NULL)
+ __pthread_mutex_condwait_completelock(mutex);
+ else
+ pthread_mutex_lock(mutex);
return 0;
}
@@ -242,9 +286,27 @@
th = dequeue(&cond->__c_waiting);
__pthread_unlock(&cond->__c_lock);
if (th != NULL) {
- th->p_condvar_avail = 1;
- WRITE_MEMORY_BARRIER();
- restart(th);
+ pthread_mutex_t *mutex = th->p_condwait_mutex;
+ if (th->p_condvar_avail == 0 &&
+ mutex != NULL &&
+ (mutex->__m_kind == PTHREAD_MUTEX_ERRORCHECK_NP ||
+ mutex->__m_kind == PTHREAD_MUTEX_TIMED_NP) &&
+ __pthread_alt_condwait_queuelock(&mutex->__m_lock, th) == 0) {
+ th->p_condwait_mutex = NULL;
+ th->p_condwait_extra_restart = 0;
+ WRITE_MEMORY_BARRIER();
+ th->p_condvar_avail = 1;
+ WRITE_MEMORY_BARRIER();
+ if (th->p_condwait_waitnode.abandoned) {
+ th->p_condwait_extra_restart = 1;
+ WRITE_MEMORY_BARRIER();
+ restart(th);
+ }
+ } else {
+ th->p_condvar_avail = 1;
+ WRITE_MEMORY_BARRIER();
+ restart(th);
+ }
}
return 0;
}
@@ -260,9 +322,27 @@
__pthread_unlock(&cond->__c_lock);
/* Now signal each process in the queue */
while ((th = dequeue(&tosignal)) != NULL) {
- th->p_condvar_avail = 1;
- WRITE_MEMORY_BARRIER();
- restart(th);
+ pthread_mutex_t *mutex = th->p_condwait_mutex;
+ if (th->p_condvar_avail == 0 &&
+ mutex != NULL &&
+ (mutex->__m_kind == PTHREAD_MUTEX_ERRORCHECK_NP ||
+ mutex->__m_kind == PTHREAD_MUTEX_TIMED_NP) &&
+ __pthread_alt_condwait_queuelock(&mutex->__m_lock, th) == 0) {
+ th->p_condwait_mutex = NULL;
+ th->p_condwait_extra_restart = 0;
+ WRITE_MEMORY_BARRIER();
+ th->p_condvar_avail = 1;
+ WRITE_MEMORY_BARRIER();
+ if (th->p_condwait_waitnode.abandoned) {
+ th->p_condwait_extra_restart = 1;
+ WRITE_MEMORY_BARRIER();
+ restart(th);
+ }
+ } else {
+ th->p_condvar_avail = 1;
+ WRITE_MEMORY_BARRIER();
+ restart(th);
+ }
}
return 0;
}
diff -ru ../../work.orig/linuxthreads-2.2.3_1/internals.h ./internals.h
--- ../../work.orig/linuxthreads-2.2.3_1/internals.h Wed Jul 18 07:25:04 2001
+++ ./internals.h Wed Jul 18 10:55:57 2001
@@ -125,6 +125,13 @@
int pr_lock_count;
} pthread_readlock_info;
+
+struct wait_node {
+ struct wait_node *next; /* Next node in null terminated linked list */
+ pthread_descr thr; /* The thread waiting with this node */
+ int abandoned; /* Atomic flag */
+};
+
struct _pthread_descr_struct {
union {
struct {
@@ -189,6 +196,9 @@
hp_timing_t p_cpuclock_offset; /* Initial CPU clock for thread. */
#endif
/* New elements must be added at the end. */
+ pthread_mutex_t *p_condwait_mutex;
+ struct wait_node p_condwait_waitnode;
+ char p_condwait_extra_restart;
} __attribute__ ((aligned(32))); /* We need to align the structure so that
doubles are aligned properly. This is 8
bytes on MIPS and 16 bytes on MIPS64.
diff -ru ../../work.orig/linuxthreads-2.2.3_1/mutex.c ./mutex.c
--- ../../work.orig/linuxthreads-2.2.3_1/mutex.c Sun Jan 7 04:35:20 2001
+++ ./mutex.c Wed Jul 18 09:09:13 2001
@@ -92,6 +92,24 @@
}
strong_alias (__pthread_mutex_trylock, pthread_mutex_trylock)
+int __pthread_mutex_condwait_completelock(pthread_mutex_t *mutex)
+{
+ pthread_descr self;
+
+ switch(mutex->__m_kind) {
+ case PTHREAD_MUTEX_ERRORCHECK_NP:
+ self = thread_self();
+ if (mutex->__m_owner == self) return EDEADLK;
+ mutex->__m_owner = self;
+ return 0;
+ case PTHREAD_MUTEX_TIMED_NP:
+ return 0;
+ default:
+ return EINVAL;
+ }
+}
+
+
int __pthread_mutex_lock(pthread_mutex_t * mutex)
{
pthread_descr self;
diff -ru ../../work.orig/linuxthreads-2.2.3_1/spinlock.c ./spinlock.c
--- ../../work.orig/linuxthreads-2.2.3_1/spinlock.c Wed Jul 18 07:25:04 2001
+++ ./spinlock.c Wed Jul 18 10:56:34 2001
@@ -232,12 +232,6 @@
*/
-struct wait_node {
- struct wait_node *next; /* Next node in null terminated linked list */
- pthread_descr thr; /* The thread waiting with this node */
- int abandoned; /* Atomic flag */
-};
-
static long wait_node_free_list;
#if !defined HAS_COMPARE_AND_SWAP || defined TEST_FOR_COMPARE_AND_SWAP
static int wait_node_free_list_spinlock;
@@ -360,6 +354,55 @@
}
#endif
+
+int __pthread_alt_condwait_queuelock(struct _pthread_fastlock * lock,
+ pthread_descr th)
+{
+#if defined HAS_COMPARE_AND_SWAP
+ long oldstatus, newstatus;
+#endif
+
+#if defined TEST_FOR_COMPARE_AND_SWAP
+ if (!__pthread_has_cas)
+#endif
+#if !defined HAS_COMPARE_AND_SWAP || defined TEST_FOR_COMPARE_AND_SWAP
+ {
+ __pthread_acquire(&lock->__spinlock);
+
+ if (lock->__status == 0) {
+ WRITE_MEMORY_BARRIER();
+ lock->__spinlock = __LT_SPINLOCK_INIT;
+ return 1;
+ }
+ th->p_condwait_waitnode.abandoned = 0;
+ th->p_condwait_waitnode.next = (struct wait_node *) lock->__status;
+ th->p_condwait_waitnode.thr = th;
+ lock->__status = (long) &th->p_condwait_waitnode;
+
+ WRITE_MEMORY_BARRIER();
+ lock->__spinlock = __LT_SPINLOCK_INIT;
+ return 0;
+ }
+#endif
+
+#if defined HAS_COMPARE_AND_SWAP
+ do {
+ oldstatus = lock->__status;
+ if (oldstatus == 0) {
+ return 1;
+ }
+ th->p_condwait_waitnode.thr = th;
+ newstatus = (long) &th->p_condwait_waitnode;
+ th->p_condwait_waitnode.abandoned = 0;
+ th->p_condwait_waitnode.next = (struct wait_node *) oldstatus;
+ /* Make sure the store in wait_node.next completes before performing
+ the compare-and-swap */
+ MEMORY_BARRIER();
+ } while(! __compare_and_swap(&lock->__status, oldstatus, newstatus));
+ return 0;
+#endif
+}
+
void __pthread_alt_lock(struct _pthread_fastlock * lock,
pthread_descr self)
diff -ru ../../work.orig/linuxthreads-2.2.3_1/spinlock.h ./spinlock.h
--- ../../work.orig/linuxthreads-2.2.3_1/spinlock.h Wed Jul 18 07:25:04 2001
+++ ./spinlock.h Wed Jul 18 09:14:58 2001
@@ -130,6 +130,9 @@
timed-out waits. Warning: do not mix these operations with the above ones
over the same lock object! */
+extern int __pthread_alt_condwait_queuelock(struct _pthread_fastlock * lock,
+ pthread_descr th);
+
extern void __pthread_alt_lock(struct _pthread_fastlock * lock,
pthread_descr self);
|
