Kernel: Store SchedulerThreadNode directly in Thread

Having the pointer indirection was weird and forced allocations when
adding/binding a new thread :P

kernel/include/kernel/Processor.h

@@ -22,7 +22,6 @@ namespace Kernel
 	class GDT;
 	class IDT;
 	class Scheduler;
-	class SchedulerThreadNode;
 	class Thread;
 
 #if ARCH(x86_64) || ARCH(i686)
@@ -54,8 +53,8 @@ namespace Kernel
 			union
 			{
 				TLBEntry flush_tlb;
-				SchedulerThreadNode* new_thread;
-				SchedulerThreadNode* unblock_thread;
+				Thread* new_thread;
+				Thread* unblock_thread;
 				bool dummy;
 			};
 		};

kernel/include/kernel/Scheduler.h

@@ -41,9 +41,8 @@ namespace Kernel
 		void on_timer_interrupt();
 		void on_yield(YieldRegisters*);
 
-		static BAN::ErrorOr<void> bind_thread_to_processor(Thread*, ProcessorID);
-		// if thread is already bound, this will never fail
-		BAN::ErrorOr<void> add_thread(Thread*);
+		static void bind_thread_to_processor(Thread*, ProcessorID);
+		void add_thread(Thread*);
 
 		void block_current_thread(ThreadBlocker* thread_blocker, uint64_t wake_time_ns, BaseMutex* mutex);
 		void unblock_thread(Thread*);
@@ -68,9 +67,6 @@ namespace Kernel
 
 		class ProcessorID find_least_loaded_processor() const;
 
-		void add_thread(SchedulerThreadNode*);
-		void unblock_thread(SchedulerThreadNode*);
-
 	private:
 		SchedulerQueue m_run_list;
 		SchedulerHeap m_block_list;

kernel/include/kernel/Thread.h

@@ -7,6 +7,7 @@
 #include <kernel/InterruptStack.h>
 #include <kernel/Lock/Mutex.h>
 #include <kernel/Memory/VirtualRange.h>
+#include <kernel/SchedulerThreadNode.h>
 
 #include <LibELF/AuxiliaryVector.h>
 
@@ -192,7 +193,7 @@ namespace Kernel
 		vaddr_t                    m_fsbase               { 0 };
 		vaddr_t                    m_gsbase               { 0 };
 
-		SchedulerThreadNode*       m_scheduler_node       { nullptr };
+		SchedulerThreadNode        m_scheduler_node;
 
 		YieldRegisters             m_yield_registers      { };
 

kernel/kernel/ACPI/ACPI.cpp

@@ -1069,10 +1069,11 @@ acpi_release_global_lock:
 
 			if (auto thread_or_error = Thread::create_kernel([](void*) { get().acpi_event_task(); }, nullptr); thread_or_error.is_error())
 				dwarnln("Failed to create ACPI thread, power button will not work: {}", thread_or_error.error());
-			else if (auto ret = Processor::scheduler().add_thread(thread_or_error.value()); ret.is_error())
-				dwarnln("Failed to create ACPI thread, power button will not work: {}", ret.error());
 			else
+			{
+				Processor::scheduler().add_thread(thread_or_error.value());
 				dprintln("Initialized ACPI interrupts");
+			}
 		}
 
 		if (auto ret = initialize_embedded_controllers(); ret.is_error())

kernel/kernel/ACPI/EmbeddedController.cpp

@@ -37,7 +37,7 @@ namespace Kernel::ACPI
 			return BAN::Error::from_errno(ENOMEM);
 
 		auto* thread = TRY(Thread::create_kernel([](void* ec) { static_cast<EmbeddedController*>(ec)->thread_task(); }, embedded_controller_ptr));
-		TRY(Processor::scheduler().add_thread(thread));
+		Processor::scheduler().add_thread(thread);
 
 		auto embedded_controller = BAN::UniqPtr<EmbeddedController>::adopt(embedded_controller_ptr);
 		embedded_controller->m_thread = thread;

kernel/kernel/FS/DevFS/FileSystem.cpp

@@ -63,7 +63,7 @@ namespace Kernel
 				}
 			}, s_instance
 		));
-		MUST(Processor::scheduler().add_thread(updater_thread));
+		Processor::scheduler().add_thread(updater_thread);
 
 		auto* disk_cache_drop_thread = MUST(Thread::create_kernel(
 			[](void* _devfs)
@@ -93,7 +93,7 @@ namespace Kernel
 				}
 			}, s_instance
 		));
-		MUST(Processor::scheduler().add_thread(disk_cache_drop_thread));
+		Processor::scheduler().add_thread(disk_cache_drop_thread);
 
 		auto* disk_sync_thread = MUST(Thread::create_kernel(
 			[](void* _devfs)
@@ -129,7 +129,7 @@ namespace Kernel
 				}
 			}, s_instance
 		));
-		MUST(Processor::scheduler().add_thread(disk_sync_thread));
+		Processor::scheduler().add_thread(disk_sync_thread);
 	}
 
 	void DevFileSystem::initiate_disk_cache_drop()

kernel/kernel/Input/InputDevice.cpp

@@ -307,8 +307,7 @@ namespace Kernel
 	BAN::ErrorOr<void> KeyboardDevice::initialize_tty_thread()
 	{
 		auto* thread = TRY(Thread::create_kernel(tty_keyboard_thread, nullptr));
-		ASSERT(thread);
-		TRY(Processor::scheduler().add_thread(thread));
+		Processor::scheduler().add_thread(thread);
 		return {};
 	}
 

kernel/kernel/Input/PS2/Controller.cpp

@@ -551,7 +551,7 @@ namespace Kernel::Input
 				static_cast<PS2DeviceInitInfo*>(info)->controller->device_initialize_task(info);
 			}, &info
 		));
-		TRY(Processor::scheduler().add_thread(init_thread));
+		Processor::scheduler().add_thread(init_thread);
 
 		while (!info.thread_started)
 			Processor::pause();

kernel/kernel/Networking/E1000/E1000.cpp

@@ -95,11 +95,8 @@ namespace Kernel
 		auto* thread = TRY(Thread::create_kernel([](void* e1000_ptr) {
 			static_cast<E1000*>(e1000_ptr)->receive_thread();
 		}, this));
-		if (auto ret = Processor::scheduler().add_thread(thread); ret.is_error())
-		{
-			delete thread;
-			return ret.release_error();
-		}
+
+		Processor::scheduler().add_thread(thread);
 		m_thread_is_dead = false;
 
 		return {};

kernel/kernel/Networking/Loopback.cpp

@@ -25,11 +25,8 @@ namespace Kernel
 		auto* thread = TRY(Thread::create_kernel([](void* loopback_ptr) {
 			static_cast<LoopbackInterface*>(loopback_ptr)->receive_thread();
 		}, loopback_ptr));
-		if (auto ret = Processor::scheduler().add_thread(thread); ret.is_error())
-		{
-			delete thread;
-			return ret.release_error();
-		}
+
+		Processor::scheduler().add_thread(thread);
 		loopback->m_thread_is_dead = false;
 
 		loopback->set_ipv4_address({ 127, 0, 0, 1 });

kernel/kernel/Networking/RTL8169/RTL8169.cpp

@@ -75,11 +75,8 @@ namespace Kernel
 		auto* thread = TRY(Thread::create_kernel([](void* rtl8169_ptr) {
 			static_cast<RTL8169*>(rtl8169_ptr)->receive_thread();
 		}, this));
-		if (auto ret = Processor::scheduler().add_thread(thread); ret.is_error())
-		{
-			delete thread;
-			return ret.release_error();
-		}
+
+		Processor::scheduler().add_thread(thread);
 		m_rx_thread_is_dead = false;
 
 		return {};

kernel/kernel/Networking/TCPSocket.cpp

@@ -45,7 +45,7 @@ namespace Kernel
 				reinterpret_cast<TCPSocket*>(socket_ptr)->process_task();
 			}, socket.ptr()
 		));
-		TRY(Processor::scheduler().add_thread(socket->m_thread));
+		Processor::scheduler().add_thread(socket->m_thread);
 		// hack to keep socket alive until its process starts
 		socket->ref();
 		return socket;

kernel/kernel/Process.cpp

@@ -237,9 +237,8 @@ namespace Kernel
 #endif
 		}
 
-		// NOTE: make sure the last two `MUST`s don't fail
+		// NOTE: make sure the last `MUST` doesn't fail
 		TRY(process->m_threads.reserve(1));
-		TRY(Processor::scheduler().bind_thread_to_processor(thread, Processor::current_id()));
 
 		{
 			SpinLockGuard _(s_process_lock);
@@ -247,7 +246,7 @@ namespace Kernel
 		}
 
 		MUST(process->m_threads.push_back(thread));
-		MUST(Processor::scheduler().add_thread(thread));
+		Processor::scheduler().add_thread(thread);
 
 		process_deleter.disable();
 		thread_deleter.disable();
@@ -877,9 +876,8 @@ namespace Kernel
 		Thread* thread = TRY(Thread::current().clone(forked, sp, ip));
 		BAN::ScopeGuard thread_deleter([thread] { delete thread; });
 
-		// NOTE: make sure the last two `MUST`s don't fail
+		// NOTE: make sure the last `MUST` doesn't fail
 		TRY(forked->m_threads.reserve(1));
-		TRY(Processor::scheduler().bind_thread_to_processor(thread, Processor::current_id()));
 
 		{
 			SpinLockGuard _(s_process_lock);
@@ -905,7 +903,7 @@ namespace Kernel
 		ASSERT(this == &Process::current());
 
 		MUST(forked->m_threads.push_back(thread));
-		MUST(Processor::scheduler().add_thread(thread));
+		Processor::scheduler().add_thread(thread);
 
 		process_deleter.disable();
 		thread_deleter.disable();
@@ -1072,14 +1070,6 @@ namespace Kernel
 #endif
 			}
 
-			// NOTE: bind new thread to this processor so it wont be rescheduled before end of this function
-			//       and so that adding the thread to the scheduler cannot fail
-			if (auto ret = Scheduler::bind_thread_to_processor(new_thread, Processor::current_id()); ret.is_error())
-			{
-				Processor::set_interrupt_state(InterruptState::Enabled);
-				delete new_thread;
-				return ret.release_error();
-			}
 
 			RWLockWRGuard wr_guard(m_memory_region_lock);
 
@@ -1103,7 +1093,9 @@ namespace Kernel
 			m_threads.front()->m_process = nullptr;
 			m_threads.front()->give_keep_alive_page_table(BAN::move(m_page_table));
 
-			MUST(Processor::scheduler().add_thread(new_thread));
+			// NOTE: bind new thread to this processor so it wont be rescheduled before end of this function
+			Scheduler::bind_thread_to_processor(new_thread, Processor::current_id());
+			Processor::scheduler().add_thread(new_thread);
 			m_threads.front() = new_thread;
 
 			for (size_t i = 0; i < sizeof(m_signal_handlers) / sizeof(*m_signal_handlers); i++)
@@ -3580,12 +3572,7 @@ namespace Kernel
 		LockGuard _1(m_process_lock);
 
 		TRY(m_threads.push_back(thread));
-		if (auto ret = Processor::scheduler().add_thread(thread); ret.is_error())
-		{
-			m_threads.pop_back();
-			delete thread;
-			return ret.release_error();
-		}
+		Processor::scheduler().add_thread(thread);
 
 		return thread->tid();
 	}

kernel/kernel/Scheduler.cpp

@@ -33,9 +33,6 @@ namespace Kernel
 	static SpinLock                        s_processor_info_time_lock;
 	static BAN::Array<ProcessorInfo, 0xFF> s_processor_infos;
 
-
-	static BAN::Atomic<size_t> s_next_processor_index { 0 };
-
 	BAN::ErrorOr<Scheduler*> Scheduler::create()
 	{
 		auto* scheduler = new Scheduler();
@@ -151,7 +148,6 @@ namespace Kernel
 					if (&PageTable::current() != &PageTable::kernel())
 						PageTable::kernel().load();
 					delete m_current->thread;
-					delete m_current;
 					m_thread_count--;
 					break;
 				case Thread::State::Executing:
@@ -185,7 +181,6 @@ namespace Kernel
 			if (&PageTable::current() != &PageTable::kernel())
 				PageTable::kernel().load();
 			delete m_current->thread;
-			delete m_current;
 			m_thread_count--;
 		}
 
@@ -236,7 +231,7 @@ namespace Kernel
 
 		const uint64_t current_ns = SystemTimer::get().ns_since_boot();
 		while (!m_block_list.empty() && current_ns >= m_block_list.front()->wake_time_ns)
-			unblock_thread(m_block_list.front());
+			unblock_thread(m_block_list.front()->thread);
 	}
 
 	void Scheduler::update_wake_up_deadline()
@@ -300,60 +295,6 @@ namespace Kernel
 			update_wake_up_deadline();
 	}
 
-	void Scheduler::unblock_thread(SchedulerThreadNode* node)
-	{
-		auto state = Processor::get_interrupt_state();
-		Processor::set_interrupt_state(InterruptState::Disabled);
-
-		if (node->processor_id == Processor::current_id())
-		{
-			if (!node->blocked)
-				return;
-			ASSERT(node != m_current);
-			Processor::set_disable_smp_messages(true);
-			m_block_list.pop(node);
-			if (auto* blocker = node->blocker.load())
-				blocker->remove_thread_from_block_queue(node);
-			node->blocked = false;
-			m_run_list.push(node);
-			update_most_loaded_node_list(node, &m_run_list);
-			Processor::set_disable_smp_messages(false);
-		}
-		else
-		{
-			Processor::send_smp_message(node->processor_id, {
-				.type = Processor::SMPMessage::Type::UnblockThread,
-				.unblock_thread = node
-			});
-		}
-
-		Processor::set_interrupt_state(state);
-	}
-
-	void Scheduler::add_thread(SchedulerThreadNode* node)
-	{
-		auto state = Processor::get_interrupt_state();
-		Processor::set_interrupt_state(InterruptState::Disabled);
-
-		ASSERT(node->processor_id == Processor::current_id());
-
-		if (!node->blocked)
-			m_run_list.push(node);
-		else
-		{
-			m_block_list.push(node);
-			if (m_block_list.front() == node)
-				update_wake_up_deadline();
-		}
-
-		if (auto* thread = node->thread; thread->is_userspace() && thread->has_process())
-			thread->update_processor_index_address();
-
-		m_thread_count++;
-
-		Processor::set_interrupt_state(state);
-	}
-
 	ProcessorID Scheduler::find_least_loaded_processor() const
 	{
 		ProcessorID least_loaded_id        = Processor::current_id();
@@ -535,7 +476,7 @@ namespace Kernel
 			thread_info.node->processor_id = least_loaded_id;
 			Processor::send_smp_message(least_loaded_id, {
 				.type = Processor::SMPMessage::Type::NewThread,
-				.new_thread = thread_info.node
+				.new_thread = thread_info.node->thread
 			});
 
 			thread_info = {
@@ -563,41 +504,52 @@ namespace Kernel
 		m_last_load_balance_ns += s_load_balance_interval_ns;
 	}
 
-	BAN::ErrorOr<void> Scheduler::bind_thread_to_processor(Thread* thread, ProcessorID processor_id)
+	void Scheduler::bind_thread_to_processor(Thread* thread, ProcessorID processor_id)
 	{
-		ASSERT(thread->m_scheduler_node == nullptr);
-		auto* new_node = new SchedulerThreadNode(thread);
-		if (new_node == nullptr)
-			return BAN::Error::from_errno(ENOMEM);
-
 		ASSERT(processor_id != PROCESSOR_NONE);
-		new_node->processor_id = processor_id;
-		thread->m_scheduler_node = new_node;
-
-		return {};
+		ASSERT(thread->m_scheduler_node.processor_id == PROCESSOR_NONE);
+		thread->m_scheduler_node.processor_id = processor_id;
 	}
 
-	BAN::ErrorOr<void> Scheduler::add_thread(Thread* thread)
+	void Scheduler::add_thread(Thread* thread)
 	{
-		if (thread->m_scheduler_node == nullptr)
+		ASSERT(thread);
+
+		if (thread->m_scheduler_node.processor_id == PROCESSOR_NONE)
 		{
+			static BAN::Atomic<size_t> s_next_processor_index { 0 };
 			const size_t processor_index = s_next_processor_index++ % Processor::count();
 			const auto processor_id = Processor::id_from_index(processor_index);
-			TRY(bind_thread_to_processor(thread, processor_id));
+			bind_thread_to_processor(thread, processor_id);
 		}
 
-		auto* node = thread->m_scheduler_node;
-		if (node->processor_id == Processor::current_id())
-			add_thread(node);
+		if (const auto proc_id = thread->m_scheduler_node.processor_id; proc_id != Processor::current_id())
+		{
+			Processor::send_smp_message(proc_id, {
+				.type = Processor::SMPMessage::Type::NewThread,
+				.new_thread = thread
+			});
+			return;
+		}
+
+		const auto state = Processor::get_interrupt_state();
+		Processor::set_interrupt_state(InterruptState::Disabled);
+
+		if (!thread->m_scheduler_node.blocked)
+			m_run_list.push(&thread->m_scheduler_node);
 		else
 		{
-			Processor::send_smp_message(node->processor_id, {
-				.type = Processor::SMPMessage::Type::NewThread,
-				.new_thread = node
-			});
+			m_block_list.push(&thread->m_scheduler_node);
+			if (m_block_list.front() == &thread->m_scheduler_node)
+				update_wake_up_deadline();
 		}
 
-		return {};
+		if (thread->is_userspace() && thread->has_process())
+			thread->update_processor_index_address();
+
+		m_thread_count++;
+
+		Processor::set_interrupt_state(state);
 	}
 
 	void Scheduler::block_current_thread(ThreadBlocker* blocker, uint64_t wake_time_ns, BaseMutex* mutex)
@@ -605,7 +557,7 @@ namespace Kernel
 		if (SystemTimer::get().ns_since_boot() >= wake_time_ns)
 			return;
 
-		auto state = Processor::get_interrupt_state();
+		const auto state = Processor::get_interrupt_state();
 		Processor::set_interrupt_state(InterruptState::Disabled);
 
 		ASSERT(m_current->processor_id == Processor::current_id());
@@ -639,7 +591,39 @@ namespace Kernel
 
 	void Scheduler::unblock_thread(Thread* thread)
 	{
-		unblock_thread(thread->m_scheduler_node);
+		if (const auto proc_id = thread->m_scheduler_node.processor_id; proc_id != Processor::current_id())
+		{
+			Processor::send_smp_message(proc_id, {
+				.type = Processor::SMPMessage::Type::UnblockThread,
+				.unblock_thread = thread
+			});
+			return;
+		}
+
+		const auto state = Processor::get_interrupt_state();
+		Processor::set_interrupt_state(InterruptState::Disabled);
+
+		if (!thread->m_scheduler_node.blocked)
+		{
+			Processor::set_interrupt_state(state);
+			return;
+		}
+
+		ASSERT(&thread->m_scheduler_node != m_current);
+
+		Processor::set_disable_smp_messages(true);
+
+		m_block_list.pop(&thread->m_scheduler_node);
+		if (auto* blocker = thread->m_scheduler_node.blocker.load())
+			blocker->remove_thread_from_block_queue(&thread->m_scheduler_node);
+		thread->m_scheduler_node.blocked = false;
+
+		m_run_list.push(&thread->m_scheduler_node);
+		update_most_loaded_node_list(&thread->m_scheduler_node, &m_run_list);
+
+		Processor::set_disable_smp_messages(false);
+
+		Processor::set_interrupt_state(state);
 	}
 
 	Thread& Scheduler::current_thread()

kernel/kernel/Thread.cpp

@@ -240,6 +240,7 @@ namespace Kernel
 
 	Thread::Thread(pid_t tid, Process* process)
 		: m_tid(tid), m_process(process)
+		, m_scheduler_node(this)
 	{
 		if (!s_default_sse_storage_initialized)
 			initialize_default_sse_storage();

kernel/kernel/ThreadBlocker.cpp

@@ -37,7 +37,7 @@ namespace Kernel
 			node->block_chain_prev = nullptr;
 			node->block_chain_next = nullptr;
 
-			Processor::scheduler().unblock_thread(node);
+			Processor::scheduler().unblock_thread(node->thread);
 
 			node = next;
 		}

kernel/kernel/USB/Hub/HubDriver.cpp

@@ -218,7 +218,7 @@ namespace Kernel
 		}
 
 		m_port_updater = TRY(Thread::create_kernel([](void* data) { reinterpret_cast<USBHubDriver*>(data)->port_updater_task(); }, this));
-		TRY(Processor::scheduler().add_thread(m_port_updater));
+		Processor::scheduler().add_thread(m_port_updater);
 
 		return {};
 	}

kernel/kernel/USB/XHCI/Controller.cpp

@@ -149,7 +149,7 @@ namespace Kernel
 			continue;
 
 		m_port_updater = TRY(Thread::create_kernel([](void* data) { reinterpret_cast<XHCIController*>(data)->port_updater_task(); }, this));
-		TRY(Processor::scheduler().add_thread(m_port_updater));
+		Processor::scheduler().add_thread(m_port_updater);
 
 		return {};
 	}

kernel/kernel/kernel.cpp

@@ -196,7 +196,7 @@ extern "C" void kernel_main(uint32_t boot_magic, uint32_t boot_info)
 	MUST(Processor::scheduler().initialize());
 
 	auto* init_thread = MUST(Thread::create_kernel(init2, nullptr));
-	MUST(Processor::scheduler().add_thread(init_thread));
+	Processor::scheduler().add_thread(init_thread);
 	Processor::yield();
 
 	ASSERT_NOT_REACHED();