Move runnable/non-runnable list control entirely over to Scheduler

This way, we can change how the scheduler works without having to change Thread too.

Kernel/Scheduler.cpp

@@ -6,6 +6,65 @@
 #include <Kernel/RTC.h>
 #include <Kernel/Scheduler.h>
 
+struct SchedulerData {
+    typedef IntrusiveList<Thread, &Thread::m_runnable_list_node> ThreadList;
+
+    ThreadList m_runnable_threads;
+    ThreadList m_nonrunnable_threads;
+
+    ThreadList& thread_list_for_state(Thread::State state)
+    {
+        if (Thread::is_runnable_state(state))
+            return m_runnable_threads;
+        return m_nonrunnable_threads;
+    }
+};
+
+static SchedulerData* g_scheduler_data;
+
+void Scheduler::init_thread(Thread& thread)
+{
+    g_scheduler_data->m_nonrunnable_threads.append(thread);
+}
+
+void Scheduler::update_state_for_thread(Thread& thread)
+{
+    auto& list = g_scheduler_data->thread_list_for_state(thread.state());
+
+    if (list.contains(thread))
+        return;
+
+    list.append(thread);
+}
+
+IterationDecision Scheduler::for_each_runnable_func(Function<IterationDecision(Thread&)>&& callback)
+{
+    ASSERT_INTERRUPTS_DISABLED();
+    auto& tl = g_scheduler_data->m_runnable_threads;
+    for (auto it = tl.begin(); it != tl.end();) {
+        auto thread = *it;
+        it = ++it;
+        if (callback(*thread) == IterationDecision::Break)
+            return IterationDecision::Break;
+    }
+
+    return IterationDecision::Continue;
+}
+
+IterationDecision Scheduler::for_each_nonrunnable_func(Function<IterationDecision(Thread&)>&& callback)
+{
+    ASSERT_INTERRUPTS_DISABLED();
+    auto& tl = g_scheduler_data->m_nonrunnable_threads;
+    for (auto it = tl.begin(); it != tl.end();) {
+        auto thread = *it;
+        it = ++it;
+        if (callback(*thread) == IterationDecision::Break)
+            return IterationDecision::Break;
+    }
+
+    return IterationDecision::Continue;
+}
+
 //#define LOG_EVERY_CONTEXT_SWITCH
 //#define SCHEDULER_DEBUG
 //#define SCHEDULER_RUNNABLE_DEBUG
@@ -261,7 +320,7 @@ bool Scheduler::pick_next()
     auto now_usec = now.tv_usec;
 
     // Check and unblock threads whose wait conditions have been met.
-    Thread::for_each_nonrunnable([&](Thread& thread) {
+    Scheduler::for_each_nonrunnable([&](Thread& thread) {
         thread.consider_unblock(now_sec, now_usec);
         return IterationDecision::Continue;
     });
@@ -330,7 +389,7 @@ bool Scheduler::pick_next()
     });
 #endif
 
-    auto& runnable_list = *Thread::g_runnable_threads;
+    auto& runnable_list = g_scheduler_data->m_runnable_threads;
     if (runnable_list.is_empty())
         return context_switch(s_colonel_process->main_thread());
 
@@ -488,6 +547,7 @@ Process* Scheduler::colonel()
 
 void Scheduler::initialize()
 {
+    g_scheduler_data = new SchedulerData;
     s_redirection.selector = gdt_alloc_entry();
     initialize_redirection();
     s_colonel_process = Process::create_kernel_process("colonel", nullptr);

Kernel/Scheduler.h

@@ -2,6 +2,8 @@
 
 #include <AK/Assertions.h>
 #include <AK/Types.h>
+#include <AK/Function.h>
+#include <AK/IntrusiveList.h>
 
 class Process;
 class Thread;
@@ -27,6 +29,29 @@ public:
     static bool is_active();
     static void beep();
 
+    template<typename Callback>
+    static inline IterationDecision for_each_runnable(Callback callback)
+    {
+        return for_each_runnable_func([callback](Thread& thread) {
+            return callback(thread);
+        });
+    }
+
+    template<typename Callback>
+    static inline IterationDecision for_each_nonrunnable(Callback callback)
+    {
+        return for_each_nonrunnable_func([callback](Thread& thread) {
+            return callback(thread);
+        });
+    }
+
+    static void init_thread(Thread& thread);
+    static void update_state_for_thread(Thread& thread);
+
 private:
     static void prepare_for_iret_to_new_process();
+    static IterationDecision for_each_runnable_func(Function<IterationDecision(Thread&)>&& callback);
+    static IterationDecision for_each_nonrunnable_func(Function<IterationDecision(Thread&)>&& callback);
+
 };
+

Kernel/Thread.cpp

@@ -16,9 +16,6 @@ HashTable<Thread*>& thread_table()
     return *table;
 }
 
-Thread::SchedulerThreadList* Thread::g_runnable_threads;
-Thread::SchedulerThreadList* Thread::g_nonrunnable_threads;
-
 static const u32 default_kernel_stack_size = 65536;
 static const u32 default_userspace_stack_size = 65536;
 
@@ -75,7 +72,7 @@ Thread::Thread(Process& process)
     if (m_process.pid() != 0) {
         InterruptDisabler disabler;
         thread_table().set(this);
-        g_nonrunnable_threads->append(*this);
+        Scheduler::init_thread(*this);
     }
 }
 
@@ -514,8 +511,6 @@ Thread* Thread::clone(Process& process)
 
 void Thread::initialize()
 {
-    g_runnable_threads = new SchedulerThreadList;
-    g_nonrunnable_threads = new SchedulerThreadList;
     Scheduler::initialize();
 }
 
@@ -545,15 +540,6 @@ void Thread::set_state(State new_state)
 
     m_state = new_state;
     if (m_process.pid() != 0) {
-        SchedulerThreadList* list = nullptr;
-        if (is_runnable_state(new_state))
-            list = g_runnable_threads;
-        else
-            list = g_nonrunnable_threads;
-
-        if (list->contains(*this))
-            return;
-
-        list->append(*this);
+        Scheduler::update_state_for_thread(*this);
     }
 }

Kernel/Thread.h

@@ -6,6 +6,7 @@
 #include <AK/OwnPtr.h>
 #include <AK/RefPtr.h>
 #include <AK/Vector.h>
+#include <Kernel/Scheduler.h>
 #include <Kernel/Arch/i386/CPU.h>
 #include <Kernel/KResult.h>
 #include <Kernel/UnixTypes.h>
@@ -16,7 +17,6 @@ class Alarm;
 class FileDescription;
 class Process;
 class Region;
-class Thread;
 
 enum class ShouldUnblockThread {
     No = 0,
@@ -299,10 +299,6 @@ public:
     template<typename Callback>
     static IterationDecision for_each_living(Callback);
     template<typename Callback>
-    static IterationDecision for_each_runnable(Callback);
-    template<typename Callback>
-    static IterationDecision for_each_nonrunnable(Callback);
-    template<typename Callback>
     static IterationDecision for_each(Callback);
 
     static bool is_runnable_state(Thread::State state)
@@ -313,19 +309,8 @@ public:
 private:
     IntrusiveListNode m_runnable_list_node;
 
-    typedef IntrusiveList<Thread, &Thread::m_runnable_list_node> SchedulerThreadList;
-
-public:
-    static SchedulerThreadList* g_runnable_threads;
-    static SchedulerThreadList* g_nonrunnable_threads;
-    static SchedulerThreadList* thread_list_for_state(Thread::State state)
-    {
-        if (is_runnable_state(state))
-            return g_runnable_threads;
-        return g_nonrunnable_threads;
-    }
-
 private:
+    friend class SchedulerData;
     Process& m_process;
     int m_tid { -1 };
     TSS32 m_tss;
@@ -351,20 +336,6 @@ private:
 
 HashTable<Thread*>& thread_table();
 
-template<typename Callback>
-inline IterationDecision Thread::for_each_in_state(State state, Callback callback)
-{
-    ASSERT_INTERRUPTS_DISABLED();
-    auto new_callback = [=](Thread& thread) -> IterationDecision {
-        if (thread.state() == state)
-            return callback(thread);
-        return IterationDecision::Continue;
-    };
-    if (is_runnable_state(state))
-        return for_each_runnable(new_callback);
-    return for_each_nonrunnable(new_callback);
-}
-
 template<typename Callback>
 inline IterationDecision Thread::for_each_living(Callback callback)
 {
@@ -380,38 +351,23 @@ template<typename Callback>
 inline IterationDecision Thread::for_each(Callback callback)
 {
     ASSERT_INTERRUPTS_DISABLED();
-    auto ret = for_each_runnable(callback);
+    auto ret = Scheduler::for_each_runnable(callback);
     if (ret == IterationDecision::Break)
         return ret;
-    return for_each_nonrunnable(callback);
+    return Scheduler::for_each_nonrunnable(callback);
 }
 
 template<typename Callback>
-inline IterationDecision Thread::for_each_runnable(Callback callback)
+inline IterationDecision Thread::for_each_in_state(State state, Callback callback)
 {
     ASSERT_INTERRUPTS_DISABLED();
-    auto& tl = *g_runnable_threads;
-    for (auto it = tl.begin(); it != tl.end();) {
-        auto thread = *it;
-        it = ++it;
-        if (callback(*thread) == IterationDecision::Break)
-            return IterationDecision::Break;
-    }
-
-    return IterationDecision::Continue;
+    auto new_callback = [=](Thread& thread) -> IterationDecision {
+        if (thread.state() == state)
+            return callback(thread);
+        return IterationDecision::Continue;
+    };
+    if (is_runnable_state(state))
+        return Scheduler::for_each_runnable(new_callback);
+    return Scheduler::for_each_nonrunnable(new_callback);
 }
 
-template<typename Callback>
-inline IterationDecision Thread::for_each_nonrunnable(Callback callback)
-{
-    ASSERT_INTERRUPTS_DISABLED();
-    auto& tl = *g_nonrunnable_threads;
-    for (auto it = tl.begin(); it != tl.end();) {
-        auto thread = *it;
-        it = ++it;
-        if (callback(*thread) == IterationDecision::Break)
-            return IterationDecision::Break;
-    }
-
-    return IterationDecision::Continue;
-}