long sys_cancel_reserve(pid_t pid) {
struct cpumask set;
struct pid *pid_struct;
struct task_struct *task;
struct task_struct *tmp;
int i;
int cpu_task_count[] = {0, 0, 0, 0};
printk(KERN_ALERT "[sys_cancel_reserve] PID %u\n", pid);
// locate the task_struct for the task required
if (pid == 0) {
task = current;
} else {
rcu_read_lock();
pid_struct = find_get_pid(pid);
if (!pid_struct) {
rcu_read_unlock();
return -ENODEV;
}
task = pid_task(pid_struct, PIDTYPE_PID);
if (!task) {
rcu_read_unlock();
return -ENODEV;
}
rcu_read_unlock();
}
// make sure the task has a reservation
if (task->has_reservation == 0) {
return -EINVAL;
}
if (task->has_reservation || task->energymon_node) {
cancel_reserve_hook(task); // execute cancel reserve hook
}
// cancel timers if they are active
if (hrtimer_active(&(task->T_timer))) {
hrtimer_cancel(&(task->T_timer));
}
if (hrtimer_active(&(task->C_timer))) {
hrtimer_cancel(&(task->C_timer));
}
// make runnable any task suspended by enforcement
if (task->put_to_sleep) {
task->put_to_sleep = 0;
wake_up_process(task);
}
// mark as not having a reservation
task->has_reservation = 0;
// set process CPU to 0 because it is never offline
cpumask_clear(&set);
cpumask_set_cpu(0, &set);
if (sched_setaffinity(task->pid, &set)) {
printk(KERN_INFO "[sys_cancel_reserve] failed to set CPU affinity\n");
return -EINVAL;
}
// find what cpus have tasks with reservations
rcu_read_lock();
for_each_process(tmp) {
if (tmp->has_reservation) {
cpu_task_count[task_cpu(tmp)] = 1;
}
}
rcu_read_unlock();
// Bring offline all cpus with no tasks
for (i = 0; i < NUM_CPUS; i ++) {
if (cpu_task_count[i] == 0) {
if (power_cpu(i, 0) != 0) {
printk(KERN_INFO "[sys_cancel_reserve] failed to turn off cpu %d", i);
return -EINVAL;
}
} else {
if (power_cpu(i, 1) != 0) {
printk(KERN_INFO "[sys_cancel_reserve] failed to turn on cpu %d", i);
return -EINVAL;
}
}
}
// set the frequency based on sysclock algorithm
sysclock_set();
return 0;
}
/**
* @brief 设置系统时间
* @param pclock 设置的时间值变量指针
* @return 成功时返回0, 否则返回非零值
*/
int SysClockSet(const struct sysclock *pclock)
{
sysclock_set(pclock);
return 0;
}
long sys_set_reserve(pid_t pid, struct timespec __user *user_C,
struct timespec __user *user_T, int cid) {
struct cpumask set;
struct timespec T, C, empty;
struct pid *pid_struct;
struct task_struct *task;
struct task_struct *tmp;
int i;
int cpu_task_count[] = {0, 0, 0, 0};
set_normalized_timespec(&empty, 0, 0);
// locate the task_struct for the task required
if (pid == 0) {
task = current;
} else {
rcu_read_lock();
pid_struct = find_get_pid(pid);
if (!pid_struct) {
rcu_read_unlock();
return -ENODEV;
}
task = pid_task(pid_struct, PIDTYPE_PID);
if (!task) {
rcu_read_unlock();
return -ENODEV;
}
rcu_read_unlock();
}
// get timespec struct info
if (copy_from_user(&C, user_C, sizeof(struct timespec))) {
printk(KERN_ALERT "[sys_set_reserve] failed to copy C from user\n");
return -EFAULT;
}
if (copy_from_user(&T, user_T, sizeof(struct timespec))) {
printk(KERN_ALERT "[sys_set_reserve] failed to copy T from user\n");
return -EFAULT;
}
// check for timespec validity
if ((timespec_compare(&T, &C) < 0) || !timespec_valid(&T) || !timespec_valid(&C) ||
(cid >= NUM_CPUS)) {
printk(KERN_ALERT "[sys_set_reserve] invalid T and C\n");
return -EINVAL;
}
// do a reservation admission check
cid = admission_check(task, C, T, cid);
if (cid < 0) {
return -EBUSY;
}
if (set_reserve_hook(task) != 0) {
return -EFAULT;
}
// cancel any old timers for an updated reservation
if (hrtimer_active(&(task->C_timer))) {
hrtimer_cancel(&(task->C_timer));
}
if (hrtimer_active(&(task->T_timer))) {
hrtimer_cancel(&(task->T_timer));
}
// make runnable any task suspended by enforcement
if (task->put_to_sleep) {
task->put_to_sleep = 0;
wake_up_process(task);
}
// copy into task struct ktime values
task->real_C_time = ktime_set(0, 0);
task->C_time = ktime_set(C.tv_sec, C.tv_nsec);
task->T_time = ktime_set(T.tv_sec, T.tv_nsec);
// find what cpus have tasks on them
rcu_read_lock();
for_each_process(tmp) {
if (tmp->has_reservation) {
cpu_task_count[task_cpu(tmp)] = 1;
}
}
rcu_read_unlock();
cpu_task_count[cid] = 1;
task->reserve_cpu = cid;
// Bring offline all cpus with no tasks
for (i = 0; i < NUM_CPUS; i ++) {
if (cpu_task_count[i] == 0) {
if (power_cpu(i, 0) != 0) {
printk(KERN_ALERT"[sys_set_reserve] failed to turn off cpu %d\n", i);
goto fail;
}
printk(KERN_ALERT"[sys_set_reserve] turned OFF CPU %d\n", i);
} else {
if (power_cpu(i, 1) != 0) {
printk(KERN_ALERT"[sys_set_reserve] failed to turn on cpu %d\n", i);
goto fail;
}
printk(KERN_ALERT"[sys_set_reserve] turned ON CPU %d\n", i);
}
}
// set process CPU
cpumask_clear(&set);
cpumask_set_cpu(cid, &set);
if (sched_setaffinity(pid, &set)) {
printk(KERN_ALERT"[sys_set_reserve] failed to set CPU affinity\n");
goto fail;
}
printk(KERN_ALERT "[sys_set_reserve] PID %d (C = %lld ms / T = %lld ms) CPU %u\n",
pid, ktime_to_ms(task->C_time), ktime_to_ms(task->T_time), cid);
// mark as having a reservation
task->has_reservation = 1;
// set the frequency based on sysclock algorithm
sysclock_set();
return 0;
fail:
if (task->has_reservation || task->energymon_node) {
cancel_reserve_hook(task);
}
return -EINVAL;
}
