void schedule(void)
{
int i,next,c;
struct task_struct ** p;
/* check alarm, wake up any interruptible tasks that have got a signal */
for(p = &LAST_TASK ; p > &FIRST_TASK ; --p)
if (*p) {
if ((*p)->alarm && (*p)->alarm < jiffies) {
(*p)->signal |= (1<<(SIGALRM-1));
(*p)->alarm = 0;
}
if (((*p)->signal & ~(_BLOCKABLE & (*p)->blocked)) &&
(*p)->state==TASK_INTERRUPTIBLE)
{
(*p)->state=TASK_RUNNING;
/*可中断睡眠 => 就绪*/
fprintk(3,"%d\tJ\t%d\n",(*p)->pid,jiffies);
}
}
/* this is the scheduler proper: */
while (1) {
c = -1;
next = 0;
i = NR_TASKS;
p = &task[NR_TASKS];
while (--i) {
if (!*--p)
continue;
if ((*p)->state == TASK_RUNNING && (*p)->counter > c)
c = (*p)->counter, next = i;
}
if (c) break;
for(p = &LAST_TASK ; p > &FIRST_TASK ; --p)
if (*p)
(*p)->counter = ((*p)->counter >> 1) +
(*p)->priority;
}
/*编号为next的进程 运行*/
if(current->pid != task[next] ->pid)
{
/*时间片到时程序 => 就绪*/
if(current->state == TASK_RUNNING)
fprintk(3,"%d\tJ\t%d\n",current->pid,jiffies);
fprintk(3,"%d\tR\t%d\n",task[next]->pid,jiffies);
}
switch_to(next);
}
sleep_on()
void schedule(void)
{
int i,next,c;
struct task_s
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哈工大操作系统实验3
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