Fix self sleep

run.sh

@@ -34,6 +34,16 @@ while [[ $# -gt 0 ]]; do
       QEMU_OPTS="$QEMU_OPTS -serial stdio"
       shift
       ;;
+    -mon)
+      if [ $TERM_USED ]; then
+        echo "Conflicting options!"; # (todo: there must be a way to use both...)
+        exit 1
+      fi
+      TERM_USED=true
+      # serial
+      QEMU_OPTS="$QEMU_OPTS -monitor stdio"
+      shift
+      ;;
     -int)
       if [ $TERM_USED ]; then
         echo "Conflicting options!"; # (todo: there must be a way to use both...)

src/arch/x86/task.cpp

@@ -208,22 +208,11 @@ void Scheduler::sleep_self(uint64_t diff) {
     uint64_t wake_time = micros + diff;
     while (micros <= wake_time) {
         {
-            LockGuard lm(WaitingTasks_mlock);
-
-            // TODO this is all ugly
-            // TODO: also maybe it breaks if it wakes before self_block?
-            uint64_t len1 = 0;
-            for (auto cur = &*WaitingTasks.begin(); !cur->end; cur = cur->next[0]) len1++;
-
-            assert(RunningTask != nullptr);
-            assert(WaitingTasks.add(wake_time, RunningTask) != nullptr);
-
-            uint64_t len2 = 0;
-            for (auto cur = &*WaitingTasks.begin(); !cur->end; cur = cur->next[0]) len2++;
-
-            assert(len2 - len1 == 1);
+            WaitingTasks_mlock.lock();
+            assert(cur_task() != nullptr);
+            assert(WaitingTasks.add(wake_time, extract_running_task_node()) != nullptr);
+            Scheduler::self_block(WaitingTasks_mlock);
         }
-        Scheduler::self_block();
     }
 }
 
@@ -354,8 +343,6 @@ void Scheduler::self_block() {
 }
 
 void Scheduler::self_block(Spinlock &to_unlock) {
-    assert2(!are_interrupts_enabled(), "Self blocking with enabled interrupts!");
-
     {
         SpinlockLockNoInt l(NextTasks_lock);
         to_unlock.unlock();
@@ -364,6 +351,15 @@ void Scheduler::self_block(Spinlock &to_unlock) {
     Scheduler::yield_self();
 }
 
+void Scheduler::self_block(Mutex &to_unlock) {
+    {
+        SpinlockLockNoInt l(NextTasks_lock);
+        to_unlock.unlock_nolock();
+        RunningTask->val->_state = Task::TaskState::TS_BLOCKED;
+    }
+    Scheduler::yield_self();
+}
+
 void Scheduler::unblock(Task *what) {
     assert(false);
     assert(what != nullptr);
@@ -372,6 +368,7 @@ void Scheduler::unblock(Task *what) {
     auto new_node = NextTasks.create_node(what);
     {
         SpinlockLockNoInt l(NextTasks_lock);
+        assert(what->_state != Task::TaskState::TS_RUNNING);
         what->_state = Task::TaskState::TS_RUNNING;
         NextTasks.emplace_front(new_node);
     }
@@ -383,6 +380,18 @@ void Scheduler::unblock(List<Task *>::Node *what) {
     sanity_check_frame(&what->val->_frame);
     {
         SpinlockLockNoInt l(NextTasks_lock);
+        assert(what->val->_state != Task::TaskState::TS_RUNNING);
+        what->val->_state = Task::TaskState::TS_RUNNING;
+        NextTasks.emplace_front(what);
+    }
+};
+void Scheduler::unblock_nolock(List<Task *>::Node *what) {
+    assert(what != nullptr);
+    assert(what->val->_state != Task::TaskState::TS_RUNNING);
+    sanity_check_frame(&what->val->_frame);
+    {
+        assert(NextTasks_lock.test() && NextTasks_lock.get_owner() == cur_task());
+        assert(what->val->_state != Task::TaskState::TS_RUNNING);
         what->val->_state = Task::TaskState::TS_RUNNING;
         NextTasks.emplace_front(what);
     }

src/arch/x86/task.hpp

@@ -90,10 +90,12 @@ namespace Scheduler {
     void                sleep_self(uint64_t diff);
 
     void                self_block();
-
     void                self_block(Spinlock &to_unlock);
+    void                self_block(Mutex &to_unlock);
+
     void                unblock(Task *what);
     void                unblock(List<Task *>::Node *what);
+    void                unblock_nolock(List<Task *>::Node *what);
 
     extern "C" void     switch_task(TaskFrame *cur_frame);
 

src/kernel/Spinlock.hpp

@@ -24,7 +24,7 @@ public:
 
     void spinlock() {
         assert2(!are_interrupts_enabled(), "Assuming all spinlocks are without interrupts");
-        while (!try_lock()) { Scheduler::yield_self(); } // FIXME: Should be pause!
+        while (!try_lock()) __builtin_ia32_pause();
     }
 
     void unlock() {

src/kernel/mutex.cpp

@@ -80,6 +80,22 @@ void Mutex::unlock() {
     }
     if (t) Scheduler::unblock(t);
 }
+void Mutex::unlock_nolock() {
+    bool expected = true;
+    _owner        = nullptr;
+
+    if (!locked.compare_exchange_strong(expected, false))
+        assert2(false, "Unlocking an unlocked mutex!\n");
+
+    List<Task *>::Node *t = nullptr;
+    {
+        SpinlockLockNoInt l(waiters_lock);
+        if (!waiters.empty()) {
+            t = waiters.extract_back();
+        }
+    }
+    if (t) Scheduler::unblock_nolock(t);
+}
 
 bool Mutex::test() {
     return atomic_load(&locked);

src/kernel/mutex.hpp

@@ -21,8 +21,10 @@ public:
 
     void lock();
     //    void spin_lock();
-    bool  try_lock();
-    void  unlock();
+    bool try_lock();
+    void unlock();
+    // Same as unlock, but assumes scheduler lock is taken
+    void  unlock_nolock();
     bool  test();
     Task *owner() { return _owner; }