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Kernel: Turn Thread::current and Process::current into functions

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This allows us to query the current thread and process on a
per processor basis
This commit is contained in:
Tom 2020-06-28 15:34:31 -06:00 • committed by Andreas Kling
parent cdc78515b6
commit 16783bd14d
39 changed files with 518 additions and 369 deletions
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105
Kernel/Scheduler.cpp
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@ -43,6 +43,7 @@ namespace Kernel {
SchedulerData* g_scheduler_data;
timeval g_timeofday;
RecursiveSpinLock g_scheduler_lock;
void Scheduler::init_thread(Thread& thread)
{
@ -63,7 +64,7 @@ void Scheduler::update_state_for_thread(Thread& thread)
static u32 time_slice_for(const Thread& thread)
{
// One time slice unit == 1ms
if (&thread == g_colonel)
if (&thread == Processor::current().idle_thread())
return 1;
return 10;
}
@ -74,7 +75,6 @@ timeval Scheduler::time_since_boot()
}
Thread* g_finalizer;
Thread* g_colonel;
WaitQueue* g_finalizer_wait_queue;
Atomic<bool> g_finalizer_has_work{false};
static Process* s_colonel_process;
@ -85,8 +85,9 @@ Thread::JoinBlocker::JoinBlocker(Thread& joinee, void*& joinee_exit_value)
, m_joinee_exit_value(joinee_exit_value)
{
ASSERT(m_joinee.m_joiner == nullptr);
m_joinee.m_joiner = Thread::current;
Thread::current->m_joinee = &joinee;
auto current_thread = Thread::current();
m_joinee.m_joiner = current_thread;
current_thread->m_joinee = &joinee;
}
bool Thread::JoinBlocker::should_unblock(Thread& joiner, time_t, long)
@ -268,7 +269,6 @@ bool Thread::WaitBlocker::should_unblock(Thread& thread, time_t, long)
return IterationDecision::Continue;
m_waitee_pid = child.pid();
dbg() << "Unblocking thread " << thread << " process " << thread.process() << " child exited: " << m_waitee_pid;
should_unblock = true;
return IterationDecision::Break;
});
@ -317,15 +317,16 @@ void Thread::consider_unblock(time_t now_sec, long now_usec)
void Scheduler::start()
{
ASSERT_INTERRUPTS_DISABLED();
ASSERT(!Thread::current);
Thread::current = g_colonel;
Process::current = &g_colonel->process();
g_colonel->set_ticks_left(time_slice_for(*g_colonel));
g_colonel->did_schedule();
g_colonel->set_initialized(true);
Processor::init_context(*g_colonel);
g_colonel->set_state(Thread::Running);
Processor::current().initialize_context_switching(*g_colonel);
auto& processor = Processor::current();
ASSERT(processor.current_thread() == nullptr);
auto& idle_thread = *processor.idle_thread();
processor.set_current_thread(idle_thread);
idle_thread.set_ticks_left(time_slice_for(idle_thread));
idle_thread.did_schedule();
idle_thread.set_initialized(true);
Processor::init_context(idle_thread);
idle_thread.set_state(Thread::Running);
processor.initialize_context_switching(idle_thread);
ASSERT_NOT_REACHED();
}
@ -333,12 +334,14 @@ bool Scheduler::pick_next()
{
ASSERT_INTERRUPTS_DISABLED();
ASSERT(Thread::current);
auto current_thread = Thread::current();
auto now = time_since_boot();
auto now_sec = now.tv_sec;
auto now_usec = now.tv_usec;
ScopedSpinLock lock(g_scheduler_lock);
// Check and unblock threads whose wait conditions have been met.
Scheduler::for_each_nonrunnable([&](Thread& thread) {
thread.consider_unblock(now_sec, now_usec);
@ -347,7 +350,7 @@ bool Scheduler::pick_next()
Process::for_each([&](Process& process) {
if (process.is_dead()) {
if (Process::current->pid() != process.pid() && (!process.ppid() || !Process::from_pid(process.ppid()))) {
if (current_thread->process().pid() != process.pid() && (!process.ppid() || !Process::from_pid(process.ppid()))) {
auto name = process.name();
auto pid = process.pid();
auto exit_status = Process::reap(process);
@ -363,13 +366,13 @@ bool Scheduler::pick_next()
});
// Dispatch any pending signals.
Thread::for_each_living([](Thread& thread) -> IterationDecision {
Thread::for_each_living([&](Thread& thread) -> IterationDecision {
if (!thread.has_unmasked_pending_signals())
return IterationDecision::Continue;
// FIXME: It would be nice if the Scheduler didn't have to worry about who is "current"
// For now, avoid dispatching signals to "current" and do it in a scheduling pass
// while some other process is interrupted. Otherwise a mess will be made.
if (&thread == Thread::current)
if (&thread == current_thread)
return IterationDecision::Continue;
// We know how to interrupt blocked processes, but if they are just executing
// at some random point in the kernel, let them continue.
@ -433,32 +436,33 @@ bool Scheduler::pick_next()
}
if (!thread_to_schedule)
thread_to_schedule = g_colonel;
thread_to_schedule = Processor::current().idle_thread();
#ifdef SCHEDULER_DEBUG
dbg() << "Scheduler: Switch to " << *thread_to_schedule << " @ " << String::format("%04x:%08x", thread_to_schedule->tss().cs, thread_to_schedule->tss().eip);
#endif
lock.unlock();
return context_switch(*thread_to_schedule);
}
bool Scheduler::yield()
{
//#ifdef SCHEDULER_DEBUG
#if 0
dbg() << "Scheduler: yielding thread " << *Thread::current << " in_trap: " << Processor::current().in_trap() << " in_irq: " << Processor::current().in_irq();
auto& proc = Processor::current();
auto current_thread = Thread::current();
#ifdef SCHEDULER_DEBUG
dbg() << "Scheduler: yielding thread " << *current_thread << " in_trap: " << proc.in_trap() << " in_irq: " << proc.in_irq();
#endif
InterruptDisabler disabler;
ASSERT(Thread::current);
if (Processor::current().in_irq()) {
ASSERT(current_thread != nullptr);
if (proc.in_irq()) {
// If we're handling an IRQ we can't switch context, delay until
// exiting the trap
Processor::current().invoke_scheduler_async();
proc.invoke_scheduler_async();
} else if (!Scheduler::pick_next())
return false;
//#ifdef SCHEDULER_DEBUG
#if 0
dbg() << "Scheduler: yield returns to thread " << *Thread::current << " in_trap: " << Processor::current().in_trap() << " in_irq: " << Processor::current().in_irq();
#ifdef SCHEDULER_DEBUG
dbg() << "Scheduler: yield returns to thread " << *current_thread << " in_trap: " << proc.in_trap() << " in_irq: " << proc.in_irq();
#endif
return true;
}
@ -471,7 +475,7 @@ bool Scheduler::donate_to(Thread* beneficiary, const char* reason)
return false;
(void)reason;
unsigned ticks_left = Thread::current->ticks_left();
unsigned ticks_left = Thread::current()->ticks_left();
if (!beneficiary || beneficiary->state() != Thread::Runnable || ticks_left <= 1)
return Scheduler::yield();
@ -489,30 +493,28 @@ bool Scheduler::context_switch(Thread& thread)
thread.set_ticks_left(time_slice_for(thread));
thread.did_schedule();
if (Thread::current == &thread)
auto current_thread = Thread::current();
if (current_thread == &thread)
return false;
if (Thread::current) {
if (current_thread) {
// If the last process hasn't blocked (still marked as running),
// mark it as runnable for the next round.
if (Thread::current->state() == Thread::Running)
Thread::current->set_state(Thread::Runnable);
if (current_thread->state() == Thread::Running)
current_thread->set_state(Thread::Runnable);
#ifdef LOG_EVERY_CONTEXT_SWITCH
dbg() << "Scheduler: " << *Thread::current << " -> " << thread << " [" << thread.priority() << "] " << String::format("%w", thread.tss().cs) << ":" << String::format("%x", thread.tss().eip);
dbg() << "Scheduler: " << *current_thread << " -> " << thread << " [" << thread.priority() << "] " << String::format("%w", thread.tss().cs) << ":" << String::format("%x", thread.tss().eip);
#endif
}
Thread* from = Thread::current;
Thread::current = &thread;
Process::current = &thread.process();
if (!thread.is_initialized()) {
Processor::init_context(thread);
thread.set_initialized(true);
}
thread.set_state(Thread::Running);
Processor::current().switch_context(from, &thread);
Processor::current().switch_context(current_thread, &thread);
return true;
}
@ -527,11 +529,21 @@ void Scheduler::initialize(u32 cpu)
g_scheduler_data = new SchedulerData;
g_finalizer_wait_queue = new WaitQueue;
Thread* idle_thread = nullptr;
if (cpu == 0) {
g_finalizer_has_work.store(false, AK::MemoryOrder::memory_order_release);
s_colonel_process = Process::create_kernel_process(g_colonel, "colonel", idle_loop);
g_colonel->set_priority(THREAD_PRIORITY_MIN);
s_colonel_process = Process::create_kernel_process(idle_thread, "colonel", idle_loop);
ASSERT(s_colonel_process);
ASSERT(idle_thread);
idle_thread->set_priority(THREAD_PRIORITY_MIN);
idle_thread->set_name(String::format("idle thread #%u", cpu));
} else {
ASSERT(s_colonel_process);
idle_thread = s_colonel_process->create_kernel_thread(idle_loop, THREAD_PRIORITY_MIN, String::format("idle thread #%u", cpu), false);
ASSERT(idle_thread);
}
Processor::current().set_idle_thread(*idle_thread);
}
void Scheduler::timer_tick(const RegisterState& regs)
@ -539,19 +551,20 @@ void Scheduler::timer_tick(const RegisterState& regs)
ASSERT_INTERRUPTS_DISABLED();
ASSERT(Processor::current().in_irq());
if (!Thread::current)
auto current_thread = Processor::current().current_thread();
if (!current_thread)
return;
++g_uptime;
g_timeofday = TimeManagement::now_as_timeval();
if (Process::current->is_profiling()) {
if (current_thread->process().is_profiling()) {
SmapDisabler disabler;
auto backtrace = Thread::current->raw_backtrace(regs.ebp, regs.eip);
auto backtrace = current_thread->raw_backtrace(regs.ebp, regs.eip);
auto& sample = Profiling::next_sample_slot();
sample.pid = Process::current->pid();
sample.tid = Thread::current->tid();
sample.pid = current_thread->process().pid();
sample.tid = current_thread->tid();
sample.timestamp = g_uptime;
for (size_t i = 0; i < min(backtrace.size(), Profiling::max_stack_frame_count); ++i) {
sample.frames[i] = backtrace[i];
@ -560,7 +573,7 @@ void Scheduler::timer_tick(const RegisterState& regs)
TimerQueue::the().fire();
if (Thread::current->tick())
if (current_thread->tick())
return;
ASSERT_INTERRUPTS_DISABLED();