This source file includes following definitions.
- busy_wait
- preemptirq_delay_run
- preemptirq_delay_init
- preemptirq_delay_exit
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8 #include <linux/trace_clock.h>
9 #include <linux/delay.h>
10 #include <linux/interrupt.h>
11 #include <linux/irq.h>
12 #include <linux/kernel.h>
13 #include <linux/kthread.h>
14 #include <linux/module.h>
15 #include <linux/printk.h>
16 #include <linux/string.h>
17
18 static ulong delay = 100;
19 static char test_mode[10] = "irq";
20
21 module_param_named(delay, delay, ulong, S_IRUGO);
22 module_param_string(test_mode, test_mode, 10, S_IRUGO);
23 MODULE_PARM_DESC(delay, "Period in microseconds (100 uS default)");
24 MODULE_PARM_DESC(test_mode, "Mode of the test such as preempt or irq (default irq)");
25
26 static void busy_wait(ulong time)
27 {
28 u64 start, end;
29 start = trace_clock_local();
30 do {
31 end = trace_clock_local();
32 if (kthread_should_stop())
33 break;
34 } while ((end - start) < (time * 1000));
35 }
36
37 static int preemptirq_delay_run(void *data)
38 {
39 unsigned long flags;
40
41 if (!strcmp(test_mode, "irq")) {
42 local_irq_save(flags);
43 busy_wait(delay);
44 local_irq_restore(flags);
45 } else if (!strcmp(test_mode, "preempt")) {
46 preempt_disable();
47 busy_wait(delay);
48 preempt_enable();
49 }
50
51 return 0;
52 }
53
54 static int __init preemptirq_delay_init(void)
55 {
56 char task_name[50];
57 struct task_struct *test_task;
58
59 snprintf(task_name, sizeof(task_name), "%s_test", test_mode);
60
61 test_task = kthread_run(preemptirq_delay_run, NULL, task_name);
62 return PTR_ERR_OR_ZERO(test_task);
63 }
64
65 static void __exit preemptirq_delay_exit(void)
66 {
67 return;
68 }
69
70 module_init(preemptirq_delay_init)
71 module_exit(preemptirq_delay_exit)
72 MODULE_LICENSE("GPL v2");