Tidy up signals atomics and such

vm/src/signal.rs

@@ -3,7 +3,7 @@ use crate::{PyObjectRef, PyResult, VirtualMachine};
 use std::sync::atomic::{AtomicBool, Ordering};
 
 pub const NSIG: usize = 64;
-pub(crate) static ANY_TRIGGERED: AtomicBool = AtomicBool::new(false);
+static ANY_TRIGGERED: AtomicBool = AtomicBool::new(false);
 // hack to get around const array repeat expressions, rust issue #79270
 #[allow(clippy::declare_interior_mutable_const)]
 const ATOMIC_FALSE: AtomicBool = AtomicBool::new(false);
@@ -12,24 +12,21 @@ pub(crate) static TRIGGERS: [AtomicBool; NSIG] = [ATOMIC_FALSE; NSIG];
 #[cfg_attr(feature = "flame-it", flame)]
 #[inline(always)]
 pub fn check_signals(vm: &VirtualMachine) -> PyResult<()> {
-    let signal_handlers = match &vm.signal_handlers {
-        Some(h) => h,
-        None => return Ok(()),
-    };
-
-    if !ANY_TRIGGERED.load(Ordering::Relaxed) {
+    if vm.signal_handlers.is_none() {
         return Ok(());
     }
-    ANY_TRIGGERED.store(false, Ordering::Relaxed);
 
-    trigger_signals(&signal_handlers.borrow(), vm)
+    if !ANY_TRIGGERED.swap(false, Ordering::Acquire) {
+        return Ok(());
+    }
+
+    trigger_signals(vm)
 }
 #[inline(never)]
 #[cold]
-fn trigger_signals(
-    signal_handlers: &[Option<PyObjectRef>; NSIG],
-    vm: &VirtualMachine,
-) -> PyResult<()> {
+fn trigger_signals(vm: &VirtualMachine) -> PyResult<()> {
+    // unwrap should never fail since we check above
+    let signal_handlers = vm.signal_handlers.as_ref().unwrap().borrow();
     for (signum, trigger) in TRIGGERS.iter().enumerate().skip(1) {
         let triggered = trigger.swap(false, Ordering::Relaxed);
         if triggered {
@@ -42,3 +39,7 @@ fn trigger_signals(
     }
     Ok(())
 }
+
+pub(crate) fn set_triggered() {
+    ANY_TRIGGERED.store(true, Ordering::Release);
+}

vm/src/stdlib/signal.rs

@@ -36,9 +36,8 @@ pub(crate) fn make_module(vm: &VirtualMachine) -> PyObjectRef {
 #[pymodule]
 pub(crate) mod _signal {
     use crate::{
-        function::IntoPyException,
-        signal::{check_signals, ANY_TRIGGERED, TRIGGERS},
-        PyObjectRef, PyResult, TryFromBorrowedObject, VirtualMachine,
+        function::IntoPyException, signal, PyObjectRef, PyResult, TryFromBorrowedObject,
+        VirtualMachine,
     };
     use std::sync::atomic::{self, Ordering};
 
@@ -128,7 +127,7 @@ pub(crate) mod _signal {
                         .to_owned(),
                 )),
             };
-        check_signals(vm)?;
+        signal::check_signals(vm)?;
 
         let old = unsafe { libc::signal(signalnum, sig_handler) };
         if old == SIG_ERR {
@@ -256,8 +255,8 @@ pub(crate) mod _signal {
     }
 
     extern "C" fn run_signal(signum: i32) {
-        TRIGGERS[signum as usize].store(true, Ordering::Relaxed);
-        ANY_TRIGGERED.store(true, Ordering::SeqCst);
+        signal::TRIGGERS[signum as usize].store(true, Ordering::Relaxed);
+        signal::set_triggered();
         let wakeup_fd = WAKEUP.load(Ordering::Relaxed);
         if wakeup_fd != INVALID_WAKEUP {
             let sigbyte = signum as u8;