thread_t *sched_choose() {
thread_t *td = runq_choose(&runq);
if (td) {
sched_remove(td);
return td;
}
return PCPU_GET(idle_thread);
}
/* syscall: exit - terminate execution of the current process */
void syscall_do_exit(int_registers_block *regs)
{
SYSCALL_DEBUG("[sys:%i] SYSCALL_EXIT called by process %i (%p) (thread %i)\n",
CPU_ID, cpu_table[CPU_ID].current->proc->pid, cpu_table[CPU_ID].current->proc,
cpu_table[CPU_ID].current->tid);
/* request to be killed by the system executive */
msg_send_signal(proc_role_lookup(DIOSIX_ROLE_SYSTEM_EXECUTIVE),
NULL, SIGXPROCEXIT, cpu_table[CPU_ID].current->proc->pid);
/* remove from the run queue and mark as dying */
sched_remove(cpu_table[CPU_ID].current, dead);
}
void scheduler()
{
for (;;)
{
struct process *proc =
current_proc ? current_proc->next : list_head.next;
/* Find a runnable process */
while (proc == &list_head || proc->state != PROC_STATE_RUNNING)
{
if (proc != &list_head && proc->state == PROC_STATE_DEAD)
{
/* Release the dead process */
struct process *dead = proc;
proc = proc->next;
sched_remove(dead);
proc_free(dead);
}
else
{
proc = proc->next;
}
}
close_int();
current_proc = proc;
/* Update TSS */
tss.ss0 = KERNEL_DATA_SELECTOR;
tss.esp0 = proc->kernel_stack;
flush_tss();
/* Change to process virtual address space */
set_cr3(CAST_VIRTUAL_TO_PHYSICAL(proc->page_dir));
if (!proc->context)
init_context(proc);
switch_kcontext(&sched_context, proc->context);
/* Call schedule task */
if (sched_task)
{
sched_task(current_proc);
sched_task = NULL;
}
}
}
/* syscall thread_exit - end termination of the currently running thread.
if it's the only thread in the process, the whole process will exit */
void syscall_do_thread_exit(int_registers_block *regs)
{
SYSCALL_DEBUG("[sys:%i] SYSCALL_THREAD_EXIT called by process %i (%p) (thread %i threads %i)\n",
CPU_ID, cpu_table[CPU_ID].current->proc->pid, cpu_table[CPU_ID].current->proc,
cpu_table[CPU_ID].current->tid, cpu_table[CPU_ID].current->proc->thread_count);
/* check to see if this process has only one thread */
if(cpu_table[CPU_ID].current->proc->thread_count < 2)
{
syscall_do_exit(regs);
return;
}
/* request to be killed by the system executive */
msg_send_signal(proc_role_lookup(DIOSIX_ROLE_SYSTEM_EXECUTIVE), NULL, SIGXTHREADEXIT, cpu_table[CPU_ID].current->proc->pid);
/* remove from the run queue and mark as dying */
sched_remove(cpu_table[CPU_ID].current, dead);
}
