src/interrupts/pic/pit.rs

@@ -9,7 +9,6 @@ pub fn gettick() -> u64 {
 }
 
 pub extern "x86-interrupt" fn timer_interrupt_handler(_stack_frame: InterruptStackFrame) {
-    // TODO: thread preemption
     unsafe {
         TICKS += 1;
         PICS.lock()

src/proc/scheduler/mod.rs

@@ -15,7 +15,6 @@ use futures_util::task::AtomicWaker;
 use lazy_static::lazy_static;
 
 lazy_static! {
-    // TODO: put this in a spin mutex instead
     pub static ref SCHEDULER: AsyncMutex<Scheduler> = AsyncMutex::new(Scheduler::new());
 }
 
@@ -24,7 +23,6 @@ pub type Threadt = Arc<RefCell<Thread>>;
 pub const K_THREAD_ID: ThreadId = ThreadId(0); // Kernel main thread identifier
 
 struct ThreadStream {
-    // TODO: add the double scheduler queue
     ids: ArrayQueue<ThreadId>,
     waker: AtomicWaker,
 }

src/syscalls/mod.rs

@@ -1,7 +1,7 @@
 use crate::println;
 use crate::proc::thread::{resume_k_thread, RUNNING_THREAD};
 use crate::proc::scheduler::SCHEDULER;
-use crate::task::yield_executor::YieldExecutor;
+use crate::task::executor::EXECUTOR;
 use crate::task::Task;
 
 pub use ids::*;
@@ -25,6 +25,8 @@ impl SyscallContext {
     pub async fn run(&mut self) {
         println!("Running async syscall runner for {:?}", self.id);
         self.dispatch().await;
+        println!("Syscall {:?} end, unblocking thread", self.id);
+        SCHEDULER.lock().await.unblock(self.thread_id);
     }
 
     pub async fn dispatch(&mut self) {
@@ -49,9 +51,18 @@ pub fn syscall_routine(syscall_id: SyscallId) -> u64 {
     }));
     
     println!("Spawning async syscall runner");
-    let mut executor = YieldExecutor::new(context.borrow().thread_id);
+    EXECUTOR
-    executor.spawn(Task::new(syscall_runner(context.clone())));
+        .try_lock()
-    executor.run();
+        .unwrap()
+        .spawn(Task::new(syscall_runner(context.clone())));
+
+    println!("Blocking thread");
+    SCHEDULER
+        .try_lock()
+        .unwrap()
+        .block(context.borrow().thread_id);
+    println!("Returning to scheduler");
+    resume_k_thread();
 
     let res = context.borrow().res;
     res

src/syscalls/proc.rs

@@ -1,11 +1,10 @@
 use crate::println;
 use crate::proc::scheduler::SCHEDULER;
-use crate::proc::thread::resume_k_thread;
 
 use super::SyscallContext;
 
 pub async fn exit(context: &SyscallContext) {
     println!("Running exit(2)");
-    SCHEDULER.lock().await.exit(context.thread_id);
+    let mut scheduler = SCHEDULER.lock().await;
-    resume_k_thread();
+    scheduler.exit(context.thread_id);
 }

src/task/mod.rs

@@ -5,7 +5,6 @@ use core::sync::atomic::{AtomicU64, Ordering};
 use core::task::{Context, Poll};
 
 pub mod executor;
-pub mod yield_executor;
 pub mod keyboard;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]

src/task/yield_executor.rs

@@ -1,119 +0,0 @@
-
-use crate::println;
-use crate::proc::thread::{ThreadId, resume_k_thread};
-use crate::proc::scheduler::SCHEDULER;
-
-use super::{Task, TaskId};
-
-use alloc::{collections::BTreeMap, sync::Arc, task::Wake};
-use core::task::{Context, Poll, Waker};
-use crossbeam_queue::ArrayQueue;
-
-pub struct YieldExecutor {
-    tasks: BTreeMap<TaskId, Task>,
-    task_queue: Arc<ArrayQueue<TaskId>>,
-    waker_cache: BTreeMap<TaskId, Waker>,
-    thread_id: ThreadId,
-}
-
-impl YieldExecutor {
-    pub fn new(thread_id: ThreadId) -> Self {
-        YieldExecutor {
-            tasks: BTreeMap::new(),
-            task_queue: Arc::new(ArrayQueue::new(100)),
-            waker_cache: BTreeMap::new(),
-            thread_id: thread_id,
-        }
-    }
-
-    pub fn run(&mut self) {
-        loop {
-            self.run_ready_tasks();
-            if self.done() {
-                break;
-            } else {
-                println!("Blocking thread");
-                SCHEDULER
-                    .try_lock()
-                    .unwrap()
-                    .block(self.thread_id);
-                println!("Returning to scheduler");
-                resume_k_thread();
-            }
-        }
-    }
-
-    fn done(&self) -> bool {
-        self.tasks.is_empty()
-    }
-
-    pub fn spawn(&mut self, task: Task) {
-        let task_id = task.id;
-        if self.tasks.insert(task.id, task).is_some() {
-            panic!("Duplicate task ID");
-        }
-        self.task_queue.push(task_id).expect("Task queue full");
-    }
-
-    fn run_ready_tasks(&mut self) {
-        let Self {
-            tasks,
-            task_queue,
-            waker_cache,
-            thread_id,
-        } = self; // Executor destructuring
-
-        while let Ok(task_id) = task_queue.pop() {
-            let task = match tasks.get_mut(&task_id) {
-                Some(task) => task,
-                None => continue, // Task does not exist anymore
-            };
-            let waker = waker_cache
-                .entry(task_id)
-                .or_insert_with(|| YieldTaskWaker::new(task_id, task_queue.clone(), *thread_id));
-            let mut context = Context::from_waker(waker);
-            match task.poll(&mut context) {
-                Poll::Ready(()) => {
-                    // task is done
-                    tasks.remove(&task_id);
-                    waker_cache.remove(&task_id);
-                }
-                Poll::Pending => {}
-            }
-        }
-    }
-}
-
-struct YieldTaskWaker {
-    task_id: TaskId,
-    task_queue: Arc<ArrayQueue<TaskId>>,
-    thread_id: ThreadId,
-}
-
-impl YieldTaskWaker {
-    fn new(task_id: TaskId, task_queue: Arc<ArrayQueue<TaskId>>, thread_id: ThreadId) -> Waker {
-        Waker::from(Arc::new(YieldTaskWaker {
-            task_id,
-            task_queue,
-            thread_id
-        }))
-    }
-
-    fn wake_task(&self) {
-        self.task_queue.push(self.task_id).expect("Task queue full");
-        SCHEDULER
-            .try_lock()
-            .unwrap()
-            .unblock(self.thread_id);
-    }
-}
-
-impl Wake for YieldTaskWaker {
-    fn wake(self: Arc<Self>) {
-        self.wake_task();
-    }
-
-    fn wake_by_ref(self: &Arc<Self>) {
-        self.wake_task();
-    }
-}

src/utils/mutex.rs

@@ -11,7 +11,6 @@ use futures_util::task::AtomicWaker;
 #[derive(Clone)]
 struct Lock {
     lock: Arc<AtomicBool>,
-    // TODO: Make a queue of wakers
     waker: Arc<AtomicWaker>,
 }