rcore-tutorial/os/src/task/mod.rs
2022-01-24 16:12:56 -08:00

144 lines
4 KiB
Rust

mod context;
mod switch;
#[allow(clippy::module_inception)]
mod task;
use crate::loader::{get_app_data, get_num_app};
use crate::sync::UPSafeCell;
use crate::trap::TrapContext;
use alloc::vec::Vec;
use lazy_static::*;
use switch::__switch;
use task::{TaskControlBlock, TaskStatus};
pub use context::TaskContext;
pub struct TaskManager {
num_app: usize,
inner: UPSafeCell<TaskManagerInner>,
}
struct TaskManagerInner {
tasks: Vec<TaskControlBlock>,
current_task: usize,
}
lazy_static! {
pub static ref TASK_MANAGER: TaskManager = {
println!("init TASK_MANAGER");
let num_app = get_num_app();
println!("num_app = {}", num_app);
let mut tasks: Vec<TaskControlBlock> = Vec::new();
for i in 0..num_app {
tasks.push(TaskControlBlock::new(get_app_data(i), i));
}
TaskManager {
num_app,
inner: unsafe {
UPSafeCell::new(TaskManagerInner {
tasks,
current_task: 0,
})
},
}
};
}
impl TaskManager {
fn run_first_task(&self) -> ! {
let mut inner = self.inner.exclusive_access();
let next_task = &mut inner.tasks[0];
next_task.task_status = TaskStatus::Running;
let next_task_cx_ptr = &next_task.task_cx as *const TaskContext;
drop(inner);
let mut _unused = TaskContext::zero_init();
// before this, we should drop local variables that must be dropped manually
unsafe {
__switch(&mut _unused as *mut _, next_task_cx_ptr);
}
panic!("unreachable in run_first_task!");
}
fn mark_current_suspended(&self) {
let mut inner = self.inner.exclusive_access();
let cur = inner.current_task;
inner.tasks[cur].task_status = TaskStatus::Ready;
}
fn mark_current_exited(&self) {
let mut inner = self.inner.exclusive_access();
let cur = inner.current_task;
inner.tasks[cur].task_status = TaskStatus::Exited;
}
fn find_next_task(&self) -> Option<usize> {
let inner = self.inner.exclusive_access();
let current = inner.current_task;
(current + 1..current + self.num_app + 1)
.map(|id| id % self.num_app)
.find(|id| inner.tasks[*id].task_status == TaskStatus::Ready)
}
fn get_current_token(&self) -> usize {
let inner = self.inner.exclusive_access();
inner.tasks[inner.current_task].get_user_token()
}
fn get_current_trap_cx(&self) -> &'static mut TrapContext {
let inner = self.inner.exclusive_access();
inner.tasks[inner.current_task].get_trap_cx()
}
fn run_next_task(&self) {
if let Some(next) = self.find_next_task() {
let mut inner = self.inner.exclusive_access();
let current = inner.current_task;
inner.tasks[next].task_status = TaskStatus::Running;
inner.current_task = next;
let current_task_cx_ptr = &mut inner.tasks[current].task_cx as *mut TaskContext;
let next_task_cx_ptr = &inner.tasks[next].task_cx as *const TaskContext;
drop(inner);
// before this, we should drop local variables that must be dropped manually
unsafe {
__switch(current_task_cx_ptr, next_task_cx_ptr);
}
// go back to user mode
} else {
panic!("All applications completed!");
}
}
}
pub fn run_first_task() {
TASK_MANAGER.run_first_task();
}
fn run_next_task() {
TASK_MANAGER.run_next_task();
}
fn mark_current_suspended() {
TASK_MANAGER.mark_current_suspended();
}
fn mark_current_exited() {
TASK_MANAGER.mark_current_exited();
}
pub fn suspend_current_and_run_next() {
mark_current_suspended();
run_next_task();
}
pub fn exit_current_and_run_next() {
mark_current_exited();
run_next_task();
}
pub fn current_user_token() -> usize {
TASK_MANAGER.get_current_token()
}
pub fn current_trap_cx() -> &'static mut TrapContext {
TASK_MANAGER.get_current_trap_cx()
}