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Exclusive UPSafeCell: A RefCell wrapper

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This commit is contained in:
Yifan Wu 2021-07-19 23:56:32 +08:00
parent fd00e8de3a
commit 93ea7f9d4d
3 changed files with 26 additions and 20 deletions
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24
os/src/task/mod.rs
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@ -27,12 +27,12 @@ lazy_static! {
let mut tasks = [
TaskControlBlock {
task_cx: TaskContext::zero_init(),
task_status: TaskStatus::UnInit
task_status: TaskStatus::UnInit
};
MAX_APP_NUM
];
for i in 0..num_app {
tasks[i].task_cx = TaskContext::goto_restore(init_app_cx(i));
tasks[i].task_cx = TaskContext::goto_restore(init_app_cx(i));
tasks[i].task_status = TaskStatus::Ready;
}
TaskManager {
@ -46,33 +46,37 @@ lazy_static! {
}
impl TaskManager {
fn run_first_task(&self) {
let task0 = &mut self.inner.upsafe_access().tasks[0];
fn run_first_task(&self) -> ! {
let mut inner = self.inner.exclusive_access();
let task0 = &mut inner.tasks[0];
task0.task_status = TaskStatus::Running;
let next_task_cx_ptr = &task0.task_cx as *const TaskContext;
let next_task_cx_ptr = &task0.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 TaskContext,
next_task_cx_ptr,
);
}
panic!("unreachable in run_first_task!");
}
fn mark_current_suspended(&self) {
let mut inner = self.inner.upsafe_access();
let mut inner = self.inner.exclusive_access();
let current = inner.current_task;
inner.tasks[current].task_status = TaskStatus::Ready;
}
fn mark_current_exited(&self) {
let mut inner = self.inner.upsafe_access();
let mut inner = self.inner.exclusive_access();
let current = inner.current_task;
inner.tasks[current].task_status = TaskStatus::Exited;
}
fn find_next_task(&self) -> Option<usize> {
let inner = self.inner.upsafe_access();
let inner = self.inner.exclusive_access();
let current = inner.current_task;
(current + 1..current + self.num_app + 1)
.map(|id| id % self.num_app)
@ -83,19 +87,21 @@ impl TaskManager {
fn run_next_task(&self) {
if let Some(next) = self.find_next_task() {
let mut inner = self.inner.upsafe_access();
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!");
}