avoid the usage of blocking spinlock by polling the wasm interface

Author: stlankes

src/executor/mod.rs

@@ -113,7 +113,7 @@ pub(crate) fn run() {
 )]
 pub(crate) fn spawn<F>(future: F)
 where
-	F: Future<Output = ()> + 'static,
+	F: Future<Output = ()> + 'static + core::marker::Send,
 {
 	core_local::ex().spawn(AsyncTask::new(future)).detach();
 }

src/executor/network.rs

@@ -182,7 +182,7 @@ async fn dhcpv4_run() {
 					nic.dns_handle = None;
 				}
 			}
-		}
+		};
 
 		Poll::<()>::Pending
 	})
@@ -229,7 +229,7 @@ pub(crate) async fn get_query_result(query: QueryHandle) -> io::Result<Vec<IpAdd
 					ips.push(*x);
 				}
 
-					Poll::Ready(Ok(ips))
+				Poll::Ready(Ok(ips))
 			}
 			Err(GetQueryResultError::Pending) => {
 				socket.register_query_waker(query, cx.waker());

src/wasm/mod.rs

@@ -6,6 +6,7 @@ use core::ffi::CStr;
 use core::future;
 use core::hint::black_box;
 use core::mem::MaybeUninit;
+use core::pin::pin;
 use core::task::Poll;
 
 use hermit_sync::{InterruptTicketMutex, Lazy};
@@ -579,28 +580,34 @@ impl WasmManager {
 
 async fn wasm_run() {
 	loop {
-		while let Some((fd, data)) = OUTPUT.lock().data.pop_front() {
-			let obj = match fd {
-				Descriptor::Stdout => crate::core_scheduler()
-					.get_object(fd::STDOUT_FILENO)
-					.unwrap(),
-				Descriptor::Stderr => crate::core_scheduler()
-					.get_object(fd::STDERR_FILENO)
-					.unwrap(),
-				Descriptor::RawFd(raw_fd) => crate::core_scheduler().get_object(raw_fd).unwrap(),
-				_ => panic!("Unsuppted {fd:?}"),
-			};
-
-			obj.write(&data).await.unwrap();
-		}
-
 		future::poll_fn(|cx| {
-			let mut guard = OUTPUT.lock();
-			if guard.data.is_empty() {
-				guard.waker.register(cx.waker());
-				Poll::Pending
+			if let Some(mut guard) = OUTPUT.try_lock() {
+				if let Some((fd, data)) = guard.data.pop_front() {
+					let obj = match fd {
+						Descriptor::Stdout => crate::core_scheduler()
+							.get_object(fd::STDOUT_FILENO)
+							.unwrap(),
+						Descriptor::Stderr => crate::core_scheduler()
+							.get_object(fd::STDERR_FILENO)
+							.unwrap(),
+						Descriptor::RawFd(raw_fd) => {
+							crate::core_scheduler().get_object(raw_fd).unwrap()
+						}
+						_ => panic!("Unsuppted {fd:?}"),
+					};
+
+					drop(guard);
+					while let Poll::Pending = pin!(obj.write(&data)).poll(cx) {}
+
+					cx.waker().wake_by_ref();
+					Poll::<()>::Pending
+				} else {
+					guard.waker.register(cx.waker());
+					Poll::<()>::Pending
+				}
 			} else {
-				Poll::Ready(())
+				cx.waker().wake_by_ref();
+				Poll::<()>::Pending
 			}
 		})
 		.await;