我在 vmware 播放器上安装了 minix 3，我试图在文件“proc.c”的 /usr/src/kernel 中找到一个函数。该函数称为 sched()。
它应该在这两个函数之间：
/*===========================================================================*
* dequeue *
*===========================================================================*/
void dequeue(struct proc *rp)
/* this process is no longer runnable */
{
/* A process must be removed from the scheduling queues, for example, because
* it has blocked. If the currently active process is removed, a new process
* is picked to run by calling pick_proc().
*
* This function can operate x-cpu as it always removes the process from the
* queue of the cpu the process is currently assigned to.
*/
int q = rp->p_priority; /* queue to use */
struct proc **xpp; /* iterate over queue */
struct proc *prev_xp;
u64_t tsc, tsc_delta;
struct proc **rdy_tail;
assert(proc_ptr_ok(rp));
assert(!proc_is_runnable(rp));
/* Side-effect for kernel: check if the task's stack still is ok? */
assert (!iskernelp(rp) || *priv(rp)->s_stack_guard == STACK_GUARD);
rdy_tail = get_cpu_var(rp->p_cpu, run_q_tail);
/* Now make sure that the process is not in its ready queue. Remove the
* process if it is found. A process can be made unready even if it is not
* running by being sent a signal that kills it.
*/
prev_xp = NULL;
for (xpp = get_cpu_var_ptr(rp->p_cpu, run_q_head[q]); *xpp;
xpp = &(*xpp)->p_nextready) {
if (*xpp == rp) { /* found process to remove */
*xpp = (*xpp)->p_nextready; /* replace with next chain */
if (rp == rdy_tail[q]) { /* queue tail removed */
rdy_tail[q] = prev_xp; /* set new tail */
}
break;
}
prev_xp = *xpp; /* save previous in chain */
}
/* Process accounting for scheduling */
rp->p_accounting.dequeues++;
/* this is not all that accurate on virtual machines, especially with
IO bound processes that only spend a short amount of time in the queue
at a time. */
if (!is_zero64(rp->p_accounting.enter_queue)) {
read_tsc_64(&tsc);
tsc_delta = sub64(tsc, rp->p_accounting.enter_queue);
rp->p_accounting.time_in_queue = add64(rp->p_accounting.time_in_queue,
tsc_delta);
make_zero64(rp->p_accounting.enter_queue);
}
#if DEBUG_SANITYCHECKS
assert(runqueues_ok_local());
#endif
}
*喜欢这个 / =============================================== =============================* * 预定* ================= ==================================================== ======== /
it should be here but is missing**
/*===========================================================================*
* pick_proc *
*===========================================================================*/
static struct proc * pick_proc(void)
{
/* Decide who to run now. A new process is selected an returned.
* When a billable process is selected, record it in 'bill_ptr', so that the
* clock task can tell who to bill for system time.
*
* This function always uses the run queues of the local cpu!
*/
register struct proc *rp; /* process to run */
struct proc **rdy_head;
int q; /* iterate over queues */
/* Check each of the scheduling queues for ready processes. The number of
* queues is defined in proc.h, and priorities are set in the task table.
* If there are no processes ready to run, return NULL.
*/
rdy_head = get_cpulocal_var(run_q_head);
for (q=0; q < NR_SCHED_QUEUES; q++) {
if(!(rp = rdy_head[q])) {
TRACE(VF_PICKPROC, printf("cpu %d queue %d empty\n", cpuid, q););
continue;
}
assert(proc_is_runnable(rp));
if (priv(rp)->s_flags & BILLABLE)
get_cpulocal_var(bill_ptr) = rp; /* bill for system time */
return rp;
}
return NULL;
}
我正在使用 minix_R3.2.1-972156d。有人知道吗？？？