Time

各種拿時間的方法

static __kernel_time_t get_boot_time(void)
{
    struct timespec boot_since;
    struct timespec boot_since_2;
    u64 boot_since_3;
    struct timespec now_time_v2;
    struct timespec now_time_v3;
    struct timeval now_time;

    get_monotonic_boottime(&boot_since);
    getboottime64(&boot_since_2);
    //timekeeping_clocktai(&now_time);
    boot_since_3 = local_clock();
    do_gettimeofday(&now_time);
    timekeeping_clocktai(&now_time_v2);

    now_time_v3 = ktime_to_timespec(ktime_get_real());

    printk("boottime: %lld\n", boot_since.tv_sec + (boot_since.tv_nsec ? 1 : 0));
    printk("getboottime64: %lld\n", boot_since_2.tv_sec);
    printk("local_clock: %5lu\n", (unsigned long)boot_since_3);
    printk("do_gettimeofday: %lld\n", now_time.tv_sec);
    printk("timekeeping_clocktai: %lld\n", now_time_v2.tv_sec);
    printk("ktime_get_real: %lld\n", now_time_v3.tv_sec);

    return now_time.tv_sec - boot_since.tv_sec;
}

Jiffies

http://fanli7.net/a/JAVAbiancheng/ANT/20121229/280890.html

Replace HZ * sec with msecs_to_jiffies

time_after/time_before