Struct os::task::TaskManager

pub struct TaskManager {
    num_app: usize,
    inner: UPSafeCell<TaskManagerInner>,
}

The task manager, where all the tasks are managed.

Functions implemented on TaskManager deals with all task state transitions and task context switching. For convenience, you can find wrappers around it in the module level.

Most of TaskManager are hidden behind the field inner, to defer borrowing checks to runtime. You can see examples on how to use inner in existing functions on TaskManager.

Fields

num_app: usize

total number of tasks

inner: UPSafeCell<TaskManagerInner>

use inner value to get mutable access

Implementations

impl TaskManager

fn run_first_task(&self) -> !

Run the first task in task list.

Generally, the first task in task list is an idle task (we call it zero process later). But in ch4, we load apps statically, so the first task is a real app.

fn mark_current_suspended(&self)

Change the status of current Running task into Ready.

fn mark_current_exited(&self)

Change the status of current Running task into Exited.

fn find_next_task(&self) -> Option<usize>

Find next task to run and return task id.

In this case, we only return the first Ready task in task list.

fn get_current_token(&self) -> usize

Get the current ‘Running’ task’s token.

fn get_current_trap_cx(&self) -> &'static mut TrapContext

Get the current ‘Running’ task’s trap contexts.

pub fn change_current_program_brk(&self, size: i32) -> Option<usize>

Change the current ‘Running’ task’s program break

fn run_next_task(&self)

Switch current Running task to the task we have found, or there is no Ready task and we can exit with all applications completed