rcore-tutorial/os/src/task/mod.rs
2022-01-18 02:48:50 -08:00

88 lines
2.4 KiB
Rust

mod context;
mod switch;
mod task;
mod manager;
mod processor;
mod pid;
use crate::fs::{open_file, OpenFlags};
use switch::__switch;
use task::{TaskControlBlock, TaskStatus};
use alloc::sync::Arc;
use manager::fetch_task;
use lazy_static::*;
pub use context::TaskContext;
pub use processor::{
run_tasks,
current_task,
current_user_token,
current_trap_cx,
take_current_task,
schedule,
};
pub use manager::add_task;
pub use pid::{PidHandle, pid_alloc, KernelStack};
pub fn suspend_current_and_run_next() {
// There must be an application running.
let task = take_current_task().unwrap();
// ---- access current TCB exclusively
let mut task_inner = task.inner_exclusive_access();
let task_cx_ptr = &mut task_inner.task_cx as *mut TaskContext;
// Change status to Ready
task_inner.task_status = TaskStatus::Ready;
drop(task_inner);
// ---- release current PCB
// push back to ready queue.
add_task(task);
// jump to scheduling cycle
schedule(task_cx_ptr);
}
pub fn exit_current_and_run_next(exit_code: i32) {
// take from Processor
let task = take_current_task().unwrap();
// **** access current TCB exclusively
let mut inner = task.inner_exclusive_access();
// Change status to Zombie
inner.task_status = TaskStatus::Zombie;
// Record exit code
inner.exit_code = exit_code;
// do not move to its parent but under initproc
// ++++++ access initproc TCB exclusively
{
let mut initproc_inner = INITPROC.inner_exclusive_access();
for child in inner.children.iter() {
child.inner_exclusive_access().parent = Some(Arc::downgrade(&INITPROC));
initproc_inner.children.push(child.clone());
}
}
// ++++++ release parent PCB
inner.children.clear();
// deallocate user space
inner.memory_set.recycle_data_pages();
drop(inner);
// **** release current PCB
// drop task manually to maintain rc correctly
drop(task);
// we do not have to save task context
let mut _unused = TaskContext::zero_init();
schedule(&mut _unused as *mut _);
}
lazy_static! {
pub static ref INITPROC: Arc<TaskControlBlock> = Arc::new({
let inode = open_file("initproc", OpenFlags::RDONLY).unwrap();
let v = inode.read_all();
TaskControlBlock::new(v.as_slice())
});
}
pub fn add_initproc() {
add_task(INITPROC.clone());
}