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128 lines
3.5 KiB
128 lines
3.5 KiB
use crate::interrupt;
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use crate::thread_pool::*;
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use alloc::boxed::Box;
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use alloc::sync::Arc;
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use core::cell::UnsafeCell;
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use log::*;
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/// Thread executor
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///
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/// Per-CPU struct. Defined at global.
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/// Only accessed by associated CPU with interrupt disabled.
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#[derive(Default)]
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pub struct Processor {
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inner: UnsafeCell<Option<ProcessorInner>>,
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}
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unsafe impl Sync for Processor {}
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struct ProcessorInner {
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id: usize,
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proc: Option<(Tid, Box<Context>)>,
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loop_context: Box<Context>,
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manager: Arc<ThreadPool>,
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}
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impl Processor {
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pub const fn new() -> Self {
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Processor {
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inner: UnsafeCell::new(None),
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}
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}
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pub unsafe fn init(&self, id: usize, context: Box<Context>, manager: Arc<ThreadPool>) {
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*self.inner.get() = Some(ProcessorInner {
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id,
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proc: None,
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loop_context: context,
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manager,
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});
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}
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fn inner(&self) -> &mut ProcessorInner {
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unsafe { &mut *self.inner.get() }
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.as_mut()
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.expect("Processor is not initialized")
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}
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/// Begin running processes after CPU setup.
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///
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/// This function never returns. It loops, doing:
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/// - choose a process to run
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/// - switch to start running that process
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/// - eventually that process transfers control
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/// via switch back to the scheduler.
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pub fn run(&self) -> ! {
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let inner = self.inner();
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unsafe {
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interrupt::disable_and_store();
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}
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loop {
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if let Some(proc) = inner.manager.run(inner.id) {
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trace!("CPU{} begin running thread {}", inner.id, proc.0);
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inner.proc = Some(proc);
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unsafe {
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inner
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.loop_context
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.switch_to(&mut *inner.proc.as_mut().unwrap().1);
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}
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let (tid, context) = inner.proc.take().unwrap();
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trace!("CPU{} stop running thread {}", inner.id, tid);
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inner.manager.stop(tid, context);
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} else {
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trace!("CPU{} idle", inner.id);
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unsafe {
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interrupt::enable_and_wfi();
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}
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// wait for a timer interrupt
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unsafe {
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interrupt::disable_and_store();
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}
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}
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}
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}
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/// Called by process running on this Processor.
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/// Yield and reschedule.
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///
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/// The interrupt may be enabled.
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pub fn yield_now(&self) {
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let inner = self.inner();
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unsafe {
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let flags = interrupt::disable_and_store();
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inner
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.proc
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.as_mut()
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.unwrap()
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.1
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.switch_to(&mut *inner.loop_context);
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interrupt::restore(flags);
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}
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}
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pub fn tid(&self) -> Tid {
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self.inner().proc.as_ref().unwrap().0
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}
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pub fn context(&self) -> &Context {
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&*self.inner().proc.as_ref().unwrap().1
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}
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pub fn manager(&self) -> &ThreadPool {
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&*self.inner().manager
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}
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/// Called by timer interrupt handler.
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///
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/// The interrupt should be disabled in the handler.
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pub fn tick(&self) {
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// If I'm idle, tid == None, need_reschedule == false.
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// Will go back to `run()` after interrupt return.
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let tid = self.inner().proc.as_ref().map(|p| p.0);
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let need_reschedule = self.manager().tick(self.inner().id, tid);
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if need_reschedule {
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self.yield_now();
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}
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}
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}
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