Merge pull request #2468 from zyuiop/feat/smp-race-cond

smp: always wake up core when ready

Author: mkroening

src/arch/x86_64/kernel/apic.rs

@@ -886,10 +886,7 @@ pub fn ipi_tlb_flush() {
 #[allow(unused_variables)]
 pub fn wakeup_core(core_id_to_wakeup: CoreId) {
 	#[cfg(all(feature = "smp", not(feature = "idle-poll")))]
-	if core_id_to_wakeup != core_id()
-		&& !processor::supports_mwait()
-		&& scheduler::take_core_hlt_state(core_id_to_wakeup)
-	{
+	if core_id_to_wakeup != core_id() && !processor::supports_mwait() {
 		without_interrupts(|| {
 			let apic_ids = CPU_LOCAL_APIC_IDS.lock();
 			let local_apic_id = apic_ids[core_id_to_wakeup as usize];

src/arch/x86_64/kernel/core_local.rs

@@ -1,8 +1,6 @@
 use alloc::boxed::Box;
 use core::arch::asm;
 use core::cell::Cell;
-#[cfg(feature = "smp")]
-use core::sync::atomic::AtomicBool;
 use core::sync::atomic::Ordering;
 use core::{mem, ptr};
 
@@ -34,8 +32,6 @@ pub(crate) struct CoreLocal {
 	irq_statistics: &'static IrqStatistics,
 	/// The core-local async executor.
 	ex: StaticLocalExecutor<RawSpinMutex, RawRwSpinLock>,
-	#[cfg(feature = "smp")]
-	pub hlt: AtomicBool,
 	/// Queues to handle incoming requests from the other cores
 	#[cfg(feature = "smp")]
 	pub scheduler_input: InterruptTicketMutex<SchedulerInput>,
@@ -63,8 +59,6 @@ impl CoreLocal {
 			irq_statistics,
 			ex: StaticLocalExecutor::new(),
 			#[cfg(feature = "smp")]
-			hlt: AtomicBool::new(false),
-			#[cfg(feature = "smp")]
 			scheduler_input: InterruptTicketMutex::new(SchedulerInput::new()),
 		};
 		let this = if core_id == 0 {

src/arch/x86_64/kernel/interrupts.rs

@@ -82,8 +82,6 @@ pub(crate) fn enable_and_wait() {
 			);
 		}
 	} else {
-		#[cfg(feature = "smp")]
-		crate::CoreLocal::get().hlt.store(true, Ordering::Relaxed);
 		enable_and_hlt();
 	}
 }

src/scheduler/mod.rs

@@ -8,8 +8,6 @@ use alloc::sync::Arc;
 use alloc::vec::Vec;
 use core::cell::RefCell;
 use core::ptr;
-#[cfg(all(target_arch = "x86_64", feature = "smp"))]
-use core::sync::atomic::AtomicBool;
 use core::sync::atomic::{AtomicI32, AtomicU32, Ordering};
 
 use ahash::RandomState;
@@ -40,8 +38,6 @@ static NO_TASKS: AtomicU32 = AtomicU32::new(0);
 #[cfg(feature = "smp")]
 static SCHEDULER_INPUTS: SpinMutex<Vec<&InterruptTicketMutex<SchedulerInput>>> =
 	SpinMutex::new(Vec::new());
-#[cfg(all(target_arch = "x86_64", feature = "smp"))]
-static CORE_HLT_STATE: SpinMutex<Vec<&AtomicBool>> = SpinMutex::new(Vec::new());
 /// Map between Task ID and Queue of waiting tasks
 static WAITING_TASKS: InterruptTicketMutex<BTreeMap<TaskId, VecDeque<TaskHandle>>> =
 	InterruptTicketMutex::new(BTreeMap::new());
@@ -891,19 +887,9 @@ pub(crate) fn add_current_core() {
 			core_id.try_into().unwrap(),
 			&CoreLocal::get().scheduler_input,
 		);
-		#[cfg(target_arch = "x86_64")]
-		CORE_HLT_STATE
-			.lock()
-			.insert(core_id.try_into().unwrap(), &CoreLocal::get().hlt);
 	}
 }
 
-#[inline]
-#[cfg(all(target_arch = "x86_64", feature = "smp", not(feature = "idle-poll")))]
-pub(crate) fn take_core_hlt_state(core_id: CoreId) -> bool {
-	CORE_HLT_STATE.lock()[usize::try_from(core_id).unwrap()].swap(false, Ordering::Acquire)
-}
-
 #[inline]
 #[cfg(feature = "smp")]
 fn get_scheduler_input(core_id: CoreId) -> &'static InterruptTicketMutex<SchedulerInput> {