Taskqueue : Periodic
Topics in this section,
# |
Version |
|---|---|
Freebsd |
14.1.0 |
In this program, you are going to learn
How to schedule the taskqueue ?
1#include<sys/param.h>
2#include<sys/module.h>
3#include<sys/kernel.h>
4#include<sys/malloc.h>
5#include<sys/queue.h>
6#include<sys/taskqueue.h>
7#include<sys/callout.h>
8
9 // Define the task structure
10static struct task my_task;
11
12 // Taskqueue handle
13static struct taskqueue *my_taskqueue;
14
15// Define callout structure
16static struct callout my_callout;
17
18 // Taskqueue handler
19static void task_handler(void *context, int pending)
20{
21 static int counter = 0;
22 counter++;
23 printf("Taskqueue excuted: counter : %d, pending : %d\n",counter,pending);
24}
25
26// Callout handler function to enqueue the task repeatedly
27static void callout_handler(void *arg)
28{
29 printf("Repeated taskqueue\n");
30
31 //Enqueue the task
32 taskqueue_enqueue(my_taskqueue,&my_task);
33
34 //Reschedule the callout for repeadted execution
35 callout_reset(&my_callout,hz,callout_handler,NULL);
36}
37
38static int event_handler(struct module *module, int event, void *arg)
39{
40 int e = 0;
41
42 switch(event)
43 {
44 case MOD_LOAD:
45 printf("Module loaded\n");
46
47 // Initialize the taskqueue (shared taskqueue thread)
48 my_taskqueue = taskqueue_create("my_taskqueue", M_NOWAIT, taskqueue_thread_enqueue, &my_taskqueue);
49
50 // Create taskqueue thread
51 taskqueue_start_threads(&my_taskqueue,1, PI_NET, "my_taskqueue_thread");
52
53 // Initialize the task
54 TASK_INIT(&my_task, 0, task_handler, NULL);
55
56 // Initialize and start the callout to repeatedly enqueue the task
57 callout_init(&my_callout, 1);
58 callout_reset(&my_callout,hz,callout_handler,NULL); //Repeat every second
59 break;
60
61 case MOD_UNLOAD:
62 printf("Module unloaded\n");
63
64 //Stop the taskqueue and callout
65 taskqueue_drain(my_taskqueue, &my_task);
66 callout_drain(&my_callout);
67
68 // Free the taskqueue
69 taskqueue_free(my_taskqueue);
70 break;
71
72 default:
73 e = EOPNOTSUPP;
74 break;
75 }
76return(e);
77}
78
79static moduledata_t taskqueue_data = {
80 "taskqueue_module",
81 event_handler,
82 NULL
83};
84
85DECLARE_MODULE(taskqueue_module, taskqueue_data, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);
86
1SRCS=taskqueue.c
2KMOD=taskqueue_module
3
4.include <bsd.kmod.mk>
1$ pwd
2basic_device_drivers/taskqueue_periodic
3
4
5$ ls
6taskqueue.c Makefile
7
8
9$ make
10
11$ ls
12.depend.taskqueue.o export_syms machine taskqueue.c taskqueue_module.ko
13Makefile i386 opt_global.h taskqueue.o x86
Load the module using kldload
1$ kldload -v ./taskqueue_module.ko
2Loaded ./taskqueue_module.ko, id=8
Run kldstat command to check the loaded modules
1$ kldstat
2Id Refs Address Size Name
3 1 29 0xffffffff80200000 1f6c698 kernel
4 2 1 0xffffffff8216e000 772c70 zfs.ko
5 3 1 0xffffffff828e1000 7850 cryptodev.ko
6 4 1 0xffffffff83218000 3220 intpm.ko
7 5 1 0xffffffff8321c000 2178 smbus.ko
8 6 1 0xffffffff8321f000 3360 uhid.ko
9 7 1 0xffffffff83223000 3360 wmt.ko
10 8 1 0xffffffff83227000 20b8 taskqueue_module.ko
Run dmesg command to check the kernel logs
1$ dmesg
2Module loaded
3Repeated taskqueue
4Taskqueue excuted: counter : 1, pending : 1
5Repeated taskqueue
6Taskqueue excuted: counter : 2, pending : 1
7Repeated taskqueue
8Taskqueue excuted: counter : 3, pending : 1
9Repeated taskqueue
10Taskqueue excuted: counter : 4, pending : 1
11Repeated taskqueue
12Taskqueue excuted: counter : 5, pending : 1
Unload the module using kldunload
1$ kldunload -v ./taskqueue_module.ko
2Unloading taskqueue_module.ko, id=8
Run kldstat command to check the loaded modules
1$ kldstat
2Id Refs Address Size Name
3 1 27 0xffffffff80200000 1f6c698 kernel
4 2 1 0xffffffff8216e000 772c70 zfs.ko
5 3 1 0xffffffff828e1000 7850 cryptodev.ko
6 4 1 0xffffffff83218000 3220 intpm.ko
7 5 1 0xffffffff8321c000 2178 smbus.ko
8 6 1 0xffffffff8321f000 3360 uhid.ko
9 7 1 0xffffffff83223000 3360 wmt.ko
Run dmesg command to check the kernel logs
1$ dmesg
2Module loaded
3Repeated taskqueue
4Taskqueue excuted: counter : 1, pending : 1
5Repeated taskqueue
6Taskqueue excuted: counter : 2, pending : 1
7Repeated taskqueue
8Taskqueue excuted: counter : 3, pending : 1
9Repeated taskqueue
10Taskqueue excuted: counter : 4, pending : 1
11Repeated taskqueue
12Taskqueue excuted: counter : 5, pending : 1
13Repeated taskqueue
14Taskqueue excuted: counter : 6, pending : 1
15Repeated taskqueue
16Taskqueue excuted: counter : 7, pending : 1
17Repeated taskqueue
18Taskqueue excuted: counter : 8, pending : 1
19Repeated taskqueue
20Taskqueue excuted: counter : 9, pending : 1
21Module unloaded