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
|
/*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Author : Richard GAYRAUD - 04 Nov 2003
* From Hewlett Packard Company.
* Charles P. Wright from IBM Research
*/
#ifndef __TASK__
#define __TASK__
#include <map>
#include <list>
#include <sys/types.h>
#include <string.h>
/* Forward declaration of call, so that we can define the call_list iterator
* that is referenced from call. */
class task;
typedef std::list<task *> task_list;
/* This arrangement of wheels lets us support up to 32 bit timers.
*
* If we were to put a minimum bound on timer_resol (or do some kind of dynamic
* allocation), then we could reduce the level one order by a factor of
* timer_resol. */
#define LEVEL_ONE_ORDER 12
#define LEVEL_TWO_ORDER 10
#define LEVEL_THREE_ORDER 10
#define LEVEL_ONE_SLOTS (1 << LEVEL_ONE_ORDER)
#define LEVEL_TWO_SLOTS (1 << LEVEL_TWO_ORDER)
#define LEVEL_THREE_SLOTS (1 << LEVEL_THREE_ORDER)
/* A time wheel structure as defined in Varghese and Lauck's 1996 journal
* article (based on their 1987 SOSP paper). */
class timewheel {
public:
timewheel();
int expire_paused_tasks();
/* Add a paused task and increment count. */
void add_paused_task(task *task, bool increment);
void remove_paused_task(task *task);
int size();
private:
/* How many task are in this wheel. */
int count;
unsigned int wheel_base;
/* The actual wheels. */
task_list wheel_one[LEVEL_ONE_SLOTS];
task_list wheel_two[LEVEL_TWO_SLOTS];
task_list wheel_three[LEVEL_THREE_SLOTS];
/* Calls that are paused indefinitely. */
task_list forever_list;
/* Turn a task into a list (based on wakeup). */
task_list *task2list(task *task);
};
class task {
public:
task();
virtual ~task();
virtual bool run() = 0;
/* Our abort action. */
virtual void abort() = 0;
/* Dump task info to error log. */
virtual void dump() = 0;
protected:
/* Wake this up, if we are not already awake. */
void setRunning();
/* Put us to sleep (we must be running). */
void setPaused();
/* When should this task wake up? */
virtual unsigned int wake() = 0;
/* Is this task paused or running? */
bool running;
private:
/* Run and Pause Queue Maintenance. */
void add_to_runqueue();
bool remove_from_runqueue();
void add_to_paused_tasks(bool increment);
/* This is for our complete task list. */
task_list::iterator taskit;
/* If we are running, the iterator to remove us from the running list. */
task_list::iterator runit;
/* If we are paused, the iterator to remove us from the paused list. */
task_list::iterator pauseit;
/* The list that we are stored in (only when paused) . */
task_list *pauselist;
/* The timing wheel is our friend so that it can update our list pointer. */
friend class timewheel;
};
task_list * get_running_tasks();
int expire_paused_tasks();
int paused_tasks_count();
void abort_all_tasks();
void dump_tasks();
#endif
|
