base/tasks/
executor.rs

1pub struct Executor {
2   pub tasks: BTreeMap<TaskId, Task>,
3   pub task_queue: Arc<ArrayQueue<TaskId>>,
4   pub waker_cache: BTreeMap<TaskId, Waker>,
5}
6
7impl Executor {
8   pub fn new() -> Self {
9      return Executor{
10         tasks: BTreeMap::new(),
11         task_queue: Arc::new(ArrayQueue::new(100)),
12         waker_cache: BTreeMap::new(),
13      };
14   }
15
16   pub fn spawn(&mut self, task: Task) {
17      let task_id = task.id;
18      if self.tasks.insert(task.id, task).is_some() {
19         log::error!("A task with the same identifier already exists");
20      }
21
22      self.task_queue.push(task_id).expect("queue full");
23   }
24
25   pub fn run(&mut self) -> ! {
26      loop{
27         self.run_ready_tasks();
28         self.sleep_if_idle();
29      }
30   }
31
32   pub fn run_ready_tasks(&mut self) {
33      // Destructure self to avoid borrow checker errors.
34      let Self {
35         tasks,
36         task_queue,
37         waker_cache,
38      } = self;
39
40      while let Some(task_id) = task_queue.pop() {
41         let task = match tasks.get_mut(&task_id) {
42            Some(task) => task,
43            None => continue,
44         };
45
46         let waker = waker_cache.entry(task_id)
47            .or_insert_with(|| TaskWaker::new(task_id, task_queue.clone()));
48
49         let mut context = Context::from_waker(waker);
50      }
51   }
52
53   pub fn sleep_if_idle(&self) {
54      use x86_64::instructions::interrupts::{self, enable_and_hlt};
55
56      interrupts::disable();
57      if self.task_queue.is_empty() {
58         enable_and_hlt();
59      } else {
60         interrupts::enable();
61      }
62   }
63}
64
65pub struct TaskWaker {
66   pub task_id: TaskId,
67   pub task_queue: Arc<ArrayQueue<TaskId>>,
68}
69
70impl TaskWaker {
71   pub fn new(task_id: TaskId, task_queue: Arc<ArrayQueue<TaskId>>) -> Waker {
72      Waker::from(Arc::new(TaskWaker {
73         task_id,
74         task_queue,
75      }))
76   }
77
78   pub fn wake_task(&self) {
79      self.task_queue.push(self.task_id).expect("task queue full");
80   }
81}
82
83impl Wake for TaskWaker {
84   fn wake(self: Arc<Self>) {
85      self.wake_task();
86   }
87
88   fn wake_by_ref(self: &Arc<Self>) {
89      self.wake_task();
90   }
91}
92
93// IMPORTS //
94
95use {
96   super::{Task, TaskId},
97   std_alloc::{collections::BTreeMap, sync::Arc, task::Wake},
98   core::task::{Context, Poll, Waker},
99   crossbeam_queue::ArrayQueue,
100};
base/tasks/executor.rs

base/tasks/
executor.rs
