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
|
/*****************************************************************************
Copyright (c) 2006, 2015, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2019, MariaDB Corporation.
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA
*****************************************************************************/
#include "ut0list.h"
#include "mem0mem.h"
#include "ut0wqueue.h"
/*******************************************************************//**
@file ut/ut0wqueue.cc
A work queue
Created 4/26/2006 Osku Salerma
************************************************************************/
/* Work queue. */
struct ib_wqueue_t {
ib_mutex_t mutex; /*!< mutex protecting everything */
ib_list_t* items; /*!< work item list */
os_event_t event; /*!< event we use to signal additions to list;
os_event_set() and os_event_reset() are
protected by ib_wqueue_t::mutex */
};
/****************************************************************//**
Create a new work queue.
@return work queue */
ib_wqueue_t*
ib_wqueue_create(void)
/*===================*/
{
ib_wqueue_t* wq = static_cast<ib_wqueue_t*>(
ut_malloc_nokey(sizeof(*wq)));
/* Function ib_wqueue_create() has not been used anywhere,
not necessary to instrument this mutex */
mutex_create(LATCH_ID_WORK_QUEUE, &wq->mutex);
wq->items = ib_list_create();
wq->event = os_event_create(0);
return(wq);
}
/****************************************************************//**
Free a work queue. */
void
ib_wqueue_free(
/*===========*/
ib_wqueue_t* wq) /*!< in: work queue */
{
mutex_free(&wq->mutex);
ib_list_free(wq->items);
os_event_destroy(wq->event);
ut_free(wq);
}
/****************************************************************//**
Add a work item to the queue. */
void
ib_wqueue_add(
/*==========*/
ib_wqueue_t* wq, /*!< in: work queue */
void* item, /*!< in: work item */
mem_heap_t* heap) /*!< in: memory heap to use for allocating the
list node */
{
mutex_enter(&wq->mutex);
ib_list_add_last(wq->items, item, heap);
os_event_set(wq->event);
mutex_exit(&wq->mutex);
}
/****************************************************************//**
Wait for a work item to appear in the queue.
@return work item */
void*
ib_wqueue_wait(
/*===========*/
ib_wqueue_t* wq) /*!< in: work queue */
{
ib_list_node_t* node;
for (;;) {
os_event_wait(wq->event);
mutex_enter(&wq->mutex);
node = ib_list_get_first(wq->items);
if (node) {
ib_list_remove(wq->items, node);
if (!ib_list_get_first(wq->items)) {
/* We must reset the event when the list
gets emptied. */
os_event_reset(wq->event);
}
break;
}
mutex_exit(&wq->mutex);
}
mutex_exit(&wq->mutex);
return(node->data);
}
/********************************************************************
Wait for a work item to appear in the queue for specified time. */
void*
ib_wqueue_timedwait(
/*================*/
/* out: work item or NULL on timeout*/
ib_wqueue_t* wq, /* in: work queue */
ulint wait_in_usecs) /* in: wait time in micro seconds */
{
ib_list_node_t* node = NULL;
for (;;) {
ulint error;
int64_t sig_count;
mutex_enter(&wq->mutex);
node = ib_list_get_first(wq->items);
if (node) {
ib_list_remove(wq->items, node);
mutex_exit(&wq->mutex);
break;
}
sig_count = os_event_reset(wq->event);
mutex_exit(&wq->mutex);
error = os_event_wait_time_low(wq->event,
(ulint) wait_in_usecs,
sig_count);
if (error == OS_SYNC_TIME_EXCEEDED) {
break;
}
}
return(node ? node->data : NULL);
}
/********************************************************************
Return first item on work queue or NULL if queue is empty
@return work item or NULL */
void*
ib_wqueue_nowait(
/*=============*/
ib_wqueue_t* wq) /*<! in: work queue */
{
ib_list_node_t* node = NULL;
mutex_enter(&wq->mutex);
if(!ib_list_is_empty(wq->items)) {
node = ib_list_get_first(wq->items);
if (node) {
ib_list_remove(wq->items, node);
}
}
/* We must reset the event when the list
gets emptied. */
if(ib_list_is_empty(wq->items)) {
os_event_reset(wq->event);
}
mutex_exit(&wq->mutex);
return (node ? node->data : NULL);
}
/** Check if queue is empty.
@param wq wait queue
@return whether the queue is empty */
bool ib_wqueue_is_empty(ib_wqueue_t* wq)
{
mutex_enter(&wq->mutex);
bool is_empty = ib_list_is_empty(wq->items);
mutex_exit(&wq->mutex);
return is_empty;
}
/********************************************************************
Get number of items on queue.
@return number of items on queue */
ulint
ib_wqueue_len(
/*==========*/
ib_wqueue_t* wq) /*<! in: work queue */
{
ulint len = 0;
mutex_enter(&wq->mutex);
len = ib_list_len(wq->items);
mutex_exit(&wq->mutex);
return(len);
}
|
