Kernel: Use min heap for scheduler block list

This makes insertion to block list O(log n) instead of O(n) when
blocking with wake time. This is more heavy and currently slower than
the previous implementation, but that is just because we don't really
have too many threads running at any given time. This will be more
scalable in the future and even allows implementing priorities if I ever
wish so

kernel/include/kernel/Processor.h

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

kernel/include/kernel/Scheduler.h

@@ -5,6 +5,7 @@
 #include <BAN/NoCopyMove.h>
 #include <kernel/InterruptStack.h>
 #include <kernel/ProcessorID.h>
+#include <kernel/SchedulerThreadNode.h>
 
 #include <sys/types.h>
 
@@ -14,29 +15,6 @@ namespace Kernel
 	class BaseMutex;
 	class Thread;
 	class ThreadBlocker;
-	struct SchedulerQueueNode;
-
-	class SchedulerQueue
-	{
-	public:
-		using Node = SchedulerQueueNode;
-
-	public:
-		void add_thread_to_back(Node*);
-		bool add_thread_with_wake_time(Node*); // return true if node was inserted as the first element
-		template<typename F>
-		Node* remove_with_condition(F callback);
-		void remove_node(Node*);
-		Node* front();
-		Node* pop_front();
-
-		bool empty() const { return m_head == nullptr; }
-
-	private:
-		Node* m_head { nullptr };
-		Node* m_tail { nullptr };
-	};
-
 	class Scheduler
 	{
 		BAN_NON_COPYABLE(Scheduler);
@@ -45,12 +23,12 @@ namespace Kernel
 	public:
 		struct NewThreadRequest
 		{
-			SchedulerQueue::Node* node;
+			SchedulerThreadNode* node;
 		};
 
 		struct UnblockRequest
 		{
-			SchedulerQueue::Node* node;
+			SchedulerThreadNode* node;
 		};
 
 	public:
@@ -79,9 +57,9 @@ namespace Kernel
 	private:
 		Scheduler() = default;
 
-		void add_current_to_most_loaded(SchedulerQueue* target_queue);
-		void update_most_loaded_node_queue(SchedulerQueue::Node*, SchedulerQueue* target_queue);
-		void remove_node_from_most_loaded(SchedulerQueue::Node*);
+		void add_current_to_most_loaded(void* target_list);
+		void update_most_loaded_node_list(SchedulerThreadNode*, void* target_list);
+		void remove_node_from_most_loaded(SchedulerThreadNode*);
 
 		void update_wake_up_deadline();
 		void wake_up_sleeping_threads();
@@ -90,13 +68,13 @@ namespace Kernel
 
 		class ProcessorID find_least_loaded_processor() const;
 
-		void add_thread(SchedulerQueue::Node*);
-		void unblock_thread(SchedulerQueue::Node*);
+		void add_thread(SchedulerThreadNode*);
+		void unblock_thread(SchedulerThreadNode*);
 
 	private:
-		SchedulerQueue m_run_queue;
-		SchedulerQueue m_block_queue;
-		SchedulerQueue::Node* m_current { nullptr };
+		SchedulerQueue m_run_list;
+		SchedulerHeap m_block_list;
+		SchedulerThreadNode* m_current { nullptr };
 
 		uint32_t m_thread_count { 0 };
 
@@ -108,8 +86,8 @@ namespace Kernel
 
 		struct ThreadInfo
 		{
-			SchedulerQueue*       queue { nullptr };
-			SchedulerQueue::Node* node  { nullptr };
+			void*                list { nullptr };
+			SchedulerThreadNode* node { nullptr };
 		};
 		BAN::Array<ThreadInfo, 10> m_most_loaded_threads;
 

kernel/include/kernel/SchedulerQueueNode.h

@@ -1,36 +0,0 @@
-#pragma once
-
-#include <BAN/Atomic.h>
-#include <kernel/ProcessorID.h>
-
-namespace Kernel
-{
-
-	class Thread;
-	class ThreadBlocker;
-
-	struct SchedulerQueueNode
-	{
-		SchedulerQueueNode(Thread* thread)
-			: thread(thread)
-		{}
-
-		Thread* const thread;
-
-		SchedulerQueueNode* next { nullptr };
-		SchedulerQueueNode* prev { nullptr };
-
-		uint64_t wake_time_ns { static_cast<uint64_t>(-1) };
-
-		BAN::Atomic<ThreadBlocker*> blocker { nullptr };
-		SchedulerQueueNode* block_chain_prev { nullptr };
-		SchedulerQueueNode* block_chain_next { nullptr };
-
-		ProcessorID processor_id { PROCESSOR_NONE };
-		bool blocked { false };
-
-		uint64_t last_start_ns { 0 };
-		uint64_t time_used_ns  { 0 };
-	};
-
-}

kernel/include/kernel/SchedulerThreadNode.h

@@ -0,0 +1,96 @@
+#pragma once
+
+#include <BAN/Atomic.h>
+#include <BAN/NoCopyMove.h>
+#include <kernel/ProcessorID.h>
+
+namespace Kernel
+{
+
+	class Thread;
+	class ThreadBlocker;
+
+	struct SchedulerThreadNode
+	{
+		SchedulerThreadNode(Thread* thread)
+			: thread(thread)
+			, heap({ nullptr, nullptr, nullptr })
+		{}
+
+		Thread* const thread;
+
+		union
+		{
+			struct
+			{
+				SchedulerThreadNode* next;
+				SchedulerThreadNode* prev;
+			} queue;
+			struct
+			{
+				SchedulerThreadNode* parent;
+				SchedulerThreadNode* lchild;
+				SchedulerThreadNode* rchild;
+			} heap;
+		};
+
+		uint64_t wake_time_ns { static_cast<uint64_t>(-1) };
+
+		BAN::Atomic<ThreadBlocker*> blocker { nullptr };
+		SchedulerThreadNode* block_chain_prev { nullptr };
+		SchedulerThreadNode* block_chain_next { nullptr };
+
+		ProcessorID processor_id { PROCESSOR_NONE };
+		bool blocked { false };
+
+		uint64_t last_start_ns { 0 };
+		uint64_t time_used_ns  { 0 };
+	};
+
+	class SchedulerQueue
+	{
+		BAN_NON_COPYABLE(SchedulerQueue);
+		BAN_NON_MOVABLE(SchedulerQueue);
+	public:
+		SchedulerQueue() = default;
+
+		SchedulerThreadNode* front();
+		SchedulerThreadNode* pop_front();
+
+		void push(SchedulerThreadNode*);
+		void pop(SchedulerThreadNode*);
+
+		void walk(void (*)(const SchedulerThreadNode*, void*), void*) const;
+		bool empty() const { return m_head == nullptr; }
+
+	private:
+		SchedulerThreadNode* m_head { nullptr };
+		SchedulerThreadNode* m_tail { nullptr };
+	};
+
+	class SchedulerHeap
+	{
+		BAN_NON_COPYABLE(SchedulerHeap);
+		BAN_NON_MOVABLE(SchedulerHeap);
+	public:
+		SchedulerHeap() = default;
+
+		SchedulerThreadNode* front();
+		SchedulerThreadNode* pop_front();
+
+		void push(SchedulerThreadNode*);
+		void pop(SchedulerThreadNode*);
+
+		void walk(void (*)(const SchedulerThreadNode*, void*), void*) const;
+		bool empty() const { return m_root == nullptr; }
+
+	private:
+		void walk_impl(void (*)(const SchedulerThreadNode*, void*), void*, const SchedulerThreadNode*) const;
+		void swap_nodes(SchedulerThreadNode*, SchedulerThreadNode*);
+
+	private:
+		SchedulerThreadNode* m_root { nullptr };
+		SchedulerThreadNode* m_last { nullptr };
+	};
+
+}

kernel/include/kernel/Thread.h

@@ -192,7 +192,7 @@ namespace Kernel
 		vaddr_t                    m_fsbase               { 0 };
 		vaddr_t                    m_gsbase               { 0 };
 
-		SchedulerQueueNode*        m_scheduler_node       { nullptr };
+		SchedulerThreadNode*       m_scheduler_node       { nullptr };
 
 		YieldRegisters             m_yield_registers      { };
 

kernel/include/kernel/ThreadBlocker.h

@@ -7,7 +7,7 @@
 namespace Kernel
 {
 
-	class SchedulerQueueNode;
+	class SchedulerThreadNode;
 
 	class ThreadBlocker
 	{
@@ -29,11 +29,11 @@ namespace Kernel
 		}
 
 	private:
-		void add_thread_to_block_queue(SchedulerQueueNode*);
-		void remove_thread_from_block_queue(SchedulerQueueNode*);
+		void add_thread_to_block_queue(SchedulerThreadNode*);
+		void remove_thread_from_block_queue(SchedulerThreadNode*);
 
 	private:
-		SchedulerQueueNode* m_block_chain { nullptr };
+		SchedulerThreadNode* m_block_chain { nullptr };
 		SpinLock m_lock;
 
 		friend class Scheduler;