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Properly handle current thread in rescheduling

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This commit is contained in:
wheremyfoodat
2023-07-28 20:05:26 +03:00
parent 8dd5b990be
commit e082625002
1 changed files with 7 additions and 15 deletions
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22
src/core/kernel/threads.cpp
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@@ -85,29 +85,21 @@ std::optional<int> Kernel::getNextThread() {
// See if there is a higher priority, ready thread and switch to that // See if there is a higher priority, ready thread and switch to that
void Kernel::rescheduleThreads() { void Kernel::rescheduleThreads() {
Thread& current = threads[currentThreadIndex]; // Current running thread Thread& current = threads[currentThreadIndex]; // Current running thread
ThreadStatus currentStatus = current.status; // Its status
// If the current thread is running and hasn't gone to sleep or whatever, set it to Ready instead of Running // If the current thread is running and hasn't gone to sleep or whatever, set it to Ready instead of Running
// Since rescheduleThreads will put it to wait and run another thread in the meantime // So that getNextThread will evaluate it properly
if (currentStatus == ThreadStatus::Running) { if (current.status == ThreadStatus::Running) {
currentStatus = ThreadStatus::Ready; current.status = ThreadStatus::Ready;
} }
ThreadStatus currentStatus = current.status;
current.status = ThreadStatus::Dead; // Temporarily mark it as dead so getNextThread will ignore it
std::optional<int> newThreadIndex = getNextThread(); std::optional<int> newThreadIndex = getNextThread();
current.status = currentStatus; // Restore old status
// Case 1: Another thread can run (that is not the idle thread) // Case 1: A thread can run
if (newThreadIndex.has_value() && newThreadIndex.value() != idleThreadIndex) { if (newThreadIndex.has_value()) {
switchThread(newThreadIndex.value()); switchThread(newThreadIndex.value());
} }
// Case 2: No other thread can run but this one can // Case 2: No other thread can run, straight to the idle thread
else if (currentStatus == ThreadStatus::Running) {
switchThread(currentThreadIndex);
}
// Case 3: No thread can run other than the idle thread
else { else {
switchThread(idleThreadIndex); switchThread(idleThreadIndex);
} }