| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Source of the Rust file `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/tokio-1.28.2/src/runtime/scheduler/current_thread.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>current_thread.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../../../normalize.css"><link rel="stylesheet" href="../../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../../../ayu.css" disabled><link rel="stylesheet" href="../../../../dark.css" disabled><link rel="stylesheet" href="../../../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../../../storage.js"></script><script defer src="../../../../source-script.js"></script><script defer src="../../../../source-files.js"></script><script defer src="../../../../main.js"></script><noscript><link rel="stylesheet" href="../../../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../../../tokio/index.html"><div class="logo-container"><img class="rust-logo" src="../../../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../../../tokio/index.html"><img class="rust-logo" src="../../../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| </pre><pre class="rust"><code><span class="kw">use </span><span class="kw">crate</span>::future::poll_fn; |
| <span class="kw">use </span><span class="kw">crate</span>::loom::sync::atomic::AtomicBool; |
| <span class="kw">use </span><span class="kw">crate</span>::loom::sync::{Arc, Mutex}; |
| <span class="kw">use </span><span class="kw">crate</span>::runtime::driver::{<span class="self">self</span>, Driver}; |
| <span class="kw">use </span><span class="kw">crate</span>::runtime::task::{<span class="self">self</span>, JoinHandle, OwnedTasks, Schedule, Task}; |
| <span class="kw">use </span><span class="kw">crate</span>::runtime::{blocking, context, scheduler, Config}; |
| <span class="kw">use </span><span class="kw">crate</span>::runtime::{MetricsBatch, SchedulerMetrics, WorkerMetrics}; |
| <span class="kw">use </span><span class="kw">crate</span>::sync::notify::Notify; |
| <span class="kw">use </span><span class="kw">crate</span>::util::atomic_cell::AtomicCell; |
| <span class="kw">use </span><span class="kw">crate</span>::util::{waker_ref, RngSeedGenerator, Wake, WakerRef}; |
| |
| <span class="kw">use </span>std::cell::RefCell; |
| <span class="kw">use </span>std::collections::VecDeque; |
| <span class="kw">use </span>std::fmt; |
| <span class="kw">use </span>std::future::Future; |
| <span class="kw">use </span>std::sync::atomic::Ordering::{AcqRel, Release}; |
| <span class="kw">use </span>std::task::Poll::{Pending, Ready}; |
| <span class="kw">use </span>std::time::Duration; |
| |
| <span class="doccomment">/// Executes tasks on the current thread |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>CurrentThread { |
| <span class="doccomment">/// Core scheduler data is acquired by a thread entering `block_on`. |
| </span>core: AtomicCell<Core>, |
| |
| <span class="doccomment">/// Notifier for waking up other threads to steal the |
| /// driver. |
| </span>notify: Notify, |
| } |
| |
| <span class="doccomment">/// Handle to the current thread scheduler |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>Handle { |
| <span class="doccomment">/// Scheduler state shared across threads |
| </span>shared: Shared, |
| |
| <span class="doccomment">/// Resource driver handles |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) driver: driver::Handle, |
| |
| <span class="doccomment">/// Blocking pool spawner |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) blocking_spawner: blocking::Spawner, |
| |
| <span class="doccomment">/// Current random number generator seed |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) seed_generator: RngSeedGenerator, |
| } |
| |
| <span class="doccomment">/// Data required for executing the scheduler. The struct is passed around to |
| /// a function that will perform the scheduling work and acts as a capability token. |
| </span><span class="kw">struct </span>Core { |
| <span class="doccomment">/// Scheduler run queue |
| </span>tasks: VecDeque<task::Notified<Arc<Handle>>>, |
| |
| <span class="doccomment">/// Current tick |
| </span>tick: u32, |
| |
| <span class="doccomment">/// Runtime driver |
| /// |
| /// The driver is removed before starting to park the thread |
| </span>driver: <span class="prelude-ty">Option</span><Driver>, |
| |
| <span class="doccomment">/// Metrics batch |
| </span>metrics: MetricsBatch, |
| |
| <span class="doccomment">/// True if a task panicked without being handled and the runtime is |
| /// configured to shutdown on unhandled panic. |
| </span>unhandled_panic: bool, |
| } |
| |
| <span class="doccomment">/// Scheduler state shared between threads. |
| </span><span class="kw">struct </span>Shared { |
| <span class="doccomment">/// Remote run queue. None if the `Runtime` has been dropped. |
| </span>queue: Mutex<<span class="prelude-ty">Option</span><VecDeque<task::Notified<Arc<Handle>>>>>, |
| |
| <span class="doccomment">/// Collection of all active tasks spawned onto this executor. |
| </span>owned: OwnedTasks<Arc<Handle>>, |
| |
| <span class="doccomment">/// Indicates whether the blocked on thread was woken. |
| </span>woken: AtomicBool, |
| |
| <span class="doccomment">/// Scheduler configuration options |
| </span>config: Config, |
| |
| <span class="doccomment">/// Keeps track of various runtime metrics. |
| </span>scheduler_metrics: SchedulerMetrics, |
| |
| <span class="doccomment">/// This scheduler only has one worker. |
| </span>worker_metrics: WorkerMetrics, |
| } |
| |
| <span class="doccomment">/// Thread-local context. |
| </span><span class="kw">struct </span>Context { |
| <span class="doccomment">/// Scheduler handle |
| </span>handle: Arc<Handle>, |
| |
| <span class="doccomment">/// Scheduler core, enabling the holder of `Context` to execute the |
| /// scheduler. |
| </span>core: RefCell<<span class="prelude-ty">Option</span><Box<Core>>>, |
| } |
| |
| <span class="doccomment">/// Initial queue capacity. |
| </span><span class="kw">const </span>INITIAL_CAPACITY: usize = <span class="number">64</span>; |
| |
| <span class="comment">// Tracks the current CurrentThread. |
| </span><span class="macro">scoped_thread_local!</span>(<span class="kw">static </span>CURRENT: Context); |
| |
| <span class="kw">impl </span>CurrentThread { |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>new( |
| driver: Driver, |
| driver_handle: driver::Handle, |
| blocking_spawner: blocking::Spawner, |
| seed_generator: RngSeedGenerator, |
| config: Config, |
| ) -> (CurrentThread, Arc<Handle>) { |
| <span class="kw">let </span>handle = Arc::new(Handle { |
| shared: Shared { |
| queue: Mutex::new(<span class="prelude-val">Some</span>(VecDeque::with_capacity(INITIAL_CAPACITY))), |
| owned: OwnedTasks::new(), |
| woken: AtomicBool::new(<span class="bool-val">false</span>), |
| config, |
| scheduler_metrics: SchedulerMetrics::new(), |
| worker_metrics: WorkerMetrics::new(), |
| }, |
| driver: driver_handle, |
| blocking_spawner, |
| seed_generator, |
| }); |
| |
| <span class="kw">let </span>core = AtomicCell::new(<span class="prelude-val">Some</span>(Box::new(Core { |
| tasks: VecDeque::with_capacity(INITIAL_CAPACITY), |
| tick: <span class="number">0</span>, |
| driver: <span class="prelude-val">Some</span>(driver), |
| metrics: MetricsBatch::new(), |
| unhandled_panic: <span class="bool-val">false</span>, |
| }))); |
| |
| <span class="kw">let </span>scheduler = CurrentThread { |
| core, |
| notify: Notify::new(), |
| }; |
| |
| (scheduler, handle) |
| } |
| |
| <span class="attribute">#[track_caller] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>block_on<F: Future>(<span class="kw-2">&</span><span class="self">self</span>, handle: <span class="kw-2">&</span>scheduler::Handle, future: F) -> F::Output { |
| <span class="macro">pin!</span>(future); |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>enter = <span class="kw">crate</span>::runtime::context::enter_runtime(handle, <span class="bool-val">false</span>); |
| <span class="kw">let </span>handle = handle.as_current_thread(); |
| |
| <span class="comment">// Attempt to steal the scheduler core and block_on the future if we can |
| // there, otherwise, lets select on a notification that the core is |
| // available or the future is complete. |
| </span><span class="kw">loop </span>{ |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(core) = <span class="self">self</span>.take_core(handle) { |
| <span class="kw">return </span>core.block_on(future); |
| } <span class="kw">else </span>{ |
| <span class="kw">let </span>notified = <span class="self">self</span>.notify.notified(); |
| <span class="macro">pin!</span>(notified); |
| |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(out) = enter |
| .blocking |
| .block_on(poll_fn(|cx| { |
| <span class="kw">if </span>notified.as_mut().poll(cx).is_ready() { |
| <span class="kw">return </span>Ready(<span class="prelude-val">None</span>); |
| } |
| |
| <span class="kw">if let </span>Ready(out) = future.as_mut().poll(cx) { |
| <span class="kw">return </span>Ready(<span class="prelude-val">Some</span>(out)); |
| } |
| |
| Pending |
| })) |
| .expect(<span class="string">"Failed to `Enter::block_on`"</span>) |
| { |
| <span class="kw">return </span>out; |
| } |
| } |
| } |
| } |
| |
| <span class="kw">fn </span>take_core(<span class="kw-2">&</span><span class="self">self</span>, handle: <span class="kw-2">&</span>Arc<Handle>) -> <span class="prelude-ty">Option</span><CoreGuard<<span class="lifetime">'_</span>>> { |
| <span class="kw">let </span>core = <span class="self">self</span>.core.take()<span class="question-mark">?</span>; |
| |
| <span class="prelude-val">Some</span>(CoreGuard { |
| context: Context { |
| handle: handle.clone(), |
| core: RefCell::new(<span class="prelude-val">Some</span>(core)), |
| }, |
| scheduler: <span class="self">self</span>, |
| }) |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>shutdown(<span class="kw-2">&mut </span><span class="self">self</span>, handle: <span class="kw-2">&</span>scheduler::Handle) { |
| <span class="kw">let </span>handle = handle.as_current_thread(); |
| |
| <span class="comment">// Avoid a double panic if we are currently panicking and |
| // the lock may be poisoned. |
| |
| </span><span class="kw">let </span>core = <span class="kw">match </span><span class="self">self</span>.take_core(handle) { |
| <span class="prelude-val">Some</span>(core) => core, |
| <span class="prelude-val">None </span><span class="kw">if </span>std::thread::panicking() => <span class="kw">return</span>, |
| <span class="prelude-val">None </span>=> <span class="macro">panic!</span>(<span class="string">"Oh no! We never placed the Core back, this is a bug!"</span>), |
| }; |
| |
| core.enter(|<span class="kw-2">mut </span>core, _context| { |
| <span class="comment">// Drain the OwnedTasks collection. This call also closes the |
| // collection, ensuring that no tasks are ever pushed after this |
| // call returns. |
| </span>handle.shared.owned.close_and_shutdown_all(); |
| |
| <span class="comment">// Drain local queue |
| // We already shut down every task, so we just need to drop the task. |
| </span><span class="kw">while let </span><span class="prelude-val">Some</span>(task) = core.pop_task(handle) { |
| drop(task); |
| } |
| |
| <span class="comment">// Drain remote queue and set it to None |
| </span><span class="kw">let </span>remote_queue = handle.shared.queue.lock().take(); |
| |
| <span class="comment">// Using `Option::take` to replace the shared queue with `None`. |
| // We already shut down every task, so we just need to drop the task. |
| </span><span class="kw">if let </span><span class="prelude-val">Some</span>(remote_queue) = remote_queue { |
| <span class="kw">for </span>task <span class="kw">in </span>remote_queue { |
| drop(task); |
| } |
| } |
| |
| <span class="macro">assert!</span>(handle.shared.owned.is_empty()); |
| |
| <span class="comment">// Submit metrics |
| </span>core.metrics.submit(<span class="kw-2">&</span>handle.shared.worker_metrics); |
| |
| <span class="comment">// Shutdown the resource drivers |
| </span><span class="kw">if let </span><span class="prelude-val">Some</span>(driver) = core.driver.as_mut() { |
| driver.shutdown(<span class="kw-2">&</span>handle.driver); |
| } |
| |
| (core, ()) |
| }); |
| } |
| } |
| |
| <span class="kw">impl </span>fmt::Debug <span class="kw">for </span>CurrentThread { |
| <span class="kw">fn </span>fmt(<span class="kw-2">&</span><span class="self">self</span>, fmt: <span class="kw-2">&mut </span>fmt::Formatter<<span class="lifetime">'_</span>>) -> fmt::Result { |
| fmt.debug_struct(<span class="string">"CurrentThread"</span>).finish() |
| } |
| } |
| |
| <span class="comment">// ===== impl Core ===== |
| |
| </span><span class="kw">impl </span>Core { |
| <span class="kw">fn </span>pop_task(<span class="kw-2">&mut </span><span class="self">self</span>, handle: <span class="kw-2">&</span>Handle) -> <span class="prelude-ty">Option</span><task::Notified<Arc<Handle>>> { |
| <span class="kw">let </span>ret = <span class="self">self</span>.tasks.pop_front(); |
| handle |
| .shared |
| .worker_metrics |
| .set_queue_depth(<span class="self">self</span>.tasks.len()); |
| ret |
| } |
| |
| <span class="kw">fn </span>push_task(<span class="kw-2">&mut </span><span class="self">self</span>, handle: <span class="kw-2">&</span>Handle, task: task::Notified<Arc<Handle>>) { |
| <span class="self">self</span>.tasks.push_back(task); |
| <span class="self">self</span>.metrics.inc_local_schedule_count(); |
| handle |
| .shared |
| .worker_metrics |
| .set_queue_depth(<span class="self">self</span>.tasks.len()); |
| } |
| } |
| |
| <span class="kw">fn </span>did_defer_tasks() -> bool { |
| context::with_defer(|deferred| !deferred.is_empty()).unwrap() |
| } |
| |
| <span class="kw">fn </span>wake_deferred_tasks() { |
| context::with_defer(|deferred| deferred.wake()); |
| } |
| |
| <span class="comment">// ===== impl Context ===== |
| |
| </span><span class="kw">impl </span>Context { |
| <span class="doccomment">/// Execute the closure with the given scheduler core stored in the |
| /// thread-local context. |
| </span><span class="kw">fn </span>run_task<R>(<span class="kw-2">&</span><span class="self">self</span>, <span class="kw-2">mut </span>core: Box<Core>, f: <span class="kw">impl </span>FnOnce() -> R) -> (Box<Core>, R) { |
| core.metrics.incr_poll_count(); |
| <span class="self">self</span>.enter(core, || <span class="kw">crate</span>::runtime::coop::budget(f)) |
| } |
| |
| <span class="doccomment">/// Blocks the current thread until an event is received by the driver, |
| /// including I/O events, timer events, ... |
| </span><span class="kw">fn </span>park(<span class="kw-2">&</span><span class="self">self</span>, <span class="kw-2">mut </span>core: Box<Core>, handle: <span class="kw-2">&</span>Handle) -> Box<Core> { |
| <span class="kw">let </span><span class="kw-2">mut </span>driver = core.driver.take().expect(<span class="string">"driver missing"</span>); |
| |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(f) = <span class="kw-2">&</span>handle.shared.config.before_park { |
| <span class="comment">// Incorrect lint, the closures are actually different types so `f` |
| // cannot be passed as an argument to `enter`. |
| </span><span class="attribute">#[allow(clippy::redundant_closure)] |
| </span><span class="kw">let </span>(c, <span class="kw">_</span>) = <span class="self">self</span>.enter(core, || f()); |
| core = c; |
| } |
| |
| <span class="comment">// This check will fail if `before_park` spawns a task for us to run |
| // instead of parking the thread |
| </span><span class="kw">if </span>core.tasks.is_empty() { |
| <span class="comment">// Park until the thread is signaled |
| </span>core.metrics.about_to_park(); |
| core.metrics.submit(<span class="kw-2">&</span>handle.shared.worker_metrics); |
| |
| <span class="kw">let </span>(c, <span class="kw">_</span>) = <span class="self">self</span>.enter(core, || { |
| driver.park(<span class="kw-2">&</span>handle.driver); |
| wake_deferred_tasks(); |
| }); |
| |
| core = c; |
| core.metrics.returned_from_park(); |
| } |
| |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(f) = <span class="kw-2">&</span>handle.shared.config.after_unpark { |
| <span class="comment">// Incorrect lint, the closures are actually different types so `f` |
| // cannot be passed as an argument to `enter`. |
| </span><span class="attribute">#[allow(clippy::redundant_closure)] |
| </span><span class="kw">let </span>(c, <span class="kw">_</span>) = <span class="self">self</span>.enter(core, || f()); |
| core = c; |
| } |
| |
| core.driver = <span class="prelude-val">Some</span>(driver); |
| core |
| } |
| |
| <span class="doccomment">/// Checks the driver for new events without blocking the thread. |
| </span><span class="kw">fn </span>park_yield(<span class="kw-2">&</span><span class="self">self</span>, <span class="kw-2">mut </span>core: Box<Core>, handle: <span class="kw-2">&</span>Handle) -> Box<Core> { |
| <span class="kw">let </span><span class="kw-2">mut </span>driver = core.driver.take().expect(<span class="string">"driver missing"</span>); |
| |
| core.metrics.submit(<span class="kw-2">&</span>handle.shared.worker_metrics); |
| <span class="kw">let </span>(<span class="kw-2">mut </span>core, <span class="kw">_</span>) = <span class="self">self</span>.enter(core, || { |
| driver.park_timeout(<span class="kw-2">&</span>handle.driver, Duration::from_millis(<span class="number">0</span>)); |
| wake_deferred_tasks(); |
| }); |
| |
| core.driver = <span class="prelude-val">Some</span>(driver); |
| core |
| } |
| |
| <span class="kw">fn </span>enter<R>(<span class="kw-2">&</span><span class="self">self</span>, core: Box<Core>, f: <span class="kw">impl </span>FnOnce() -> R) -> (Box<Core>, R) { |
| <span class="comment">// Store the scheduler core in the thread-local context |
| // |
| // A drop-guard is employed at a higher level. |
| </span><span class="kw-2">*</span><span class="self">self</span>.core.borrow_mut() = <span class="prelude-val">Some</span>(core); |
| |
| <span class="comment">// Execute the closure while tracking the execution budget |
| </span><span class="kw">let </span>ret = f(); |
| |
| <span class="comment">// Take the scheduler core back |
| </span><span class="kw">let </span>core = <span class="self">self</span>.core.borrow_mut().take().expect(<span class="string">"core missing"</span>); |
| (core, ret) |
| } |
| } |
| |
| <span class="comment">// ===== impl Handle ===== |
| |
| </span><span class="kw">impl </span>Handle { |
| <span class="doccomment">/// Spawns a future onto the `CurrentThread` scheduler |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>spawn<F>( |
| me: <span class="kw-2">&</span>Arc<<span class="self">Self</span>>, |
| future: F, |
| id: <span class="kw">crate</span>::runtime::task::Id, |
| ) -> JoinHandle<F::Output> |
| <span class="kw">where |
| </span>F: <span class="kw">crate</span>::future::Future + Send + <span class="lifetime">'static</span>, |
| F::Output: Send + <span class="lifetime">'static</span>, |
| { |
| <span class="kw">let </span>(handle, notified) = me.shared.owned.bind(future, me.clone(), id); |
| |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(notified) = notified { |
| me.schedule(notified); |
| } |
| |
| handle |
| } |
| |
| <span class="kw">fn </span>pop(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="prelude-ty">Option</span><task::Notified<Arc<Handle>>> { |
| <span class="kw">match </span><span class="self">self</span>.shared.queue.lock().as_mut() { |
| <span class="prelude-val">Some</span>(queue) => queue.pop_front(), |
| <span class="prelude-val">None </span>=> <span class="prelude-val">None</span>, |
| } |
| } |
| |
| <span class="kw">fn </span>waker_ref(me: <span class="kw-2">&</span>Arc<<span class="self">Self</span>>) -> WakerRef<<span class="lifetime">'_</span>> { |
| <span class="comment">// Set woken to true when enter block_on, ensure outer future |
| // be polled for the first time when enter loop |
| </span>me.shared.woken.store(<span class="bool-val">true</span>, Release); |
| waker_ref(me) |
| } |
| |
| <span class="comment">// reset woken to false and return original value |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>reset_woken(<span class="kw-2">&</span><span class="self">self</span>) -> bool { |
| <span class="self">self</span>.shared.woken.swap(<span class="bool-val">false</span>, AcqRel) |
| } |
| } |
| |
| <span class="macro">cfg_metrics! </span>{ |
| <span class="kw">impl </span>Handle { |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>scheduler_metrics(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span>SchedulerMetrics { |
| <span class="kw-2">&</span><span class="self">self</span>.shared.scheduler_metrics |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>injection_queue_depth(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| <span class="comment">// TODO: avoid having to lock. The multi-threaded injection queue |
| // could probably be used here. |
| </span><span class="self">self</span>.shared |
| .queue |
| .lock() |
| .as_ref() |
| .map(|queue| queue.len()) |
| .unwrap_or(<span class="number">0</span>) |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>worker_metrics(<span class="kw-2">&</span><span class="self">self</span>, worker: usize) -> <span class="kw-2">&</span>WorkerMetrics { |
| <span class="macro">assert_eq!</span>(<span class="number">0</span>, worker); |
| <span class="kw-2">&</span><span class="self">self</span>.shared.worker_metrics |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>num_blocking_threads(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| <span class="self">self</span>.blocking_spawner.num_threads() |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>num_idle_blocking_threads(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| <span class="self">self</span>.blocking_spawner.num_idle_threads() |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>blocking_queue_depth(<span class="kw-2">&</span><span class="self">self</span>) -> usize { |
| <span class="self">self</span>.blocking_spawner.queue_depth() |
| } |
| } |
| } |
| |
| <span class="kw">impl </span>fmt::Debug <span class="kw">for </span>Handle { |
| <span class="kw">fn </span>fmt(<span class="kw-2">&</span><span class="self">self</span>, fmt: <span class="kw-2">&mut </span>fmt::Formatter<<span class="lifetime">'_</span>>) -> fmt::Result { |
| fmt.debug_struct(<span class="string">"current_thread::Handle { ... }"</span>).finish() |
| } |
| } |
| |
| <span class="comment">// ===== impl Shared ===== |
| |
| </span><span class="kw">impl </span>Schedule <span class="kw">for </span>Arc<Handle> { |
| <span class="kw">fn </span>release(<span class="kw-2">&</span><span class="self">self</span>, task: <span class="kw-2">&</span>Task<<span class="self">Self</span>>) -> <span class="prelude-ty">Option</span><Task<<span class="self">Self</span>>> { |
| <span class="self">self</span>.shared.owned.remove(task) |
| } |
| |
| <span class="kw">fn </span>schedule(<span class="kw-2">&</span><span class="self">self</span>, task: task::Notified<<span class="self">Self</span>>) { |
| CURRENT.with(|maybe_cx| <span class="kw">match </span>maybe_cx { |
| <span class="prelude-val">Some</span>(cx) <span class="kw">if </span>Arc::ptr_eq(<span class="self">self</span>, <span class="kw-2">&</span>cx.handle) => { |
| <span class="kw">let </span><span class="kw-2">mut </span>core = cx.core.borrow_mut(); |
| |
| <span class="comment">// If `None`, the runtime is shutting down, so there is no need |
| // to schedule the task. |
| </span><span class="kw">if let </span><span class="prelude-val">Some</span>(core) = core.as_mut() { |
| core.push_task(<span class="self">self</span>, task); |
| } |
| } |
| <span class="kw">_ </span>=> { |
| <span class="comment">// Track that a task was scheduled from **outside** of the runtime. |
| </span><span class="self">self</span>.shared.scheduler_metrics.inc_remote_schedule_count(); |
| |
| <span class="comment">// If the queue is None, then the runtime has shut down. We |
| // don't need to do anything with the notification in that case. |
| </span><span class="kw">let </span><span class="kw-2">mut </span>guard = <span class="self">self</span>.shared.queue.lock(); |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(queue) = guard.as_mut() { |
| queue.push_back(task); |
| drop(guard); |
| <span class="self">self</span>.driver.unpark(); |
| } |
| } |
| }); |
| } |
| |
| <span class="macro">cfg_unstable! </span>{ |
| <span class="kw">fn </span>unhandled_panic(<span class="kw-2">&</span><span class="self">self</span>) { |
| <span class="kw">use </span><span class="kw">crate</span>::runtime::UnhandledPanic; |
| |
| <span class="kw">match </span><span class="self">self</span>.shared.config.unhandled_panic { |
| UnhandledPanic::Ignore => { |
| <span class="comment">// Do nothing |
| </span>} |
| UnhandledPanic::ShutdownRuntime => { |
| <span class="comment">// This hook is only called from within the runtime, so |
| // `CURRENT` should match with `&self`, i.e. there is no |
| // opportunity for a nested scheduler to be called. |
| </span>CURRENT.with(|maybe_cx| <span class="kw">match </span>maybe_cx { |
| <span class="prelude-val">Some</span>(cx) <span class="kw">if </span>Arc::ptr_eq(<span class="self">self</span>, <span class="kw-2">&</span>cx.handle) => { |
| <span class="kw">let </span><span class="kw-2">mut </span>core = cx.core.borrow_mut(); |
| |
| <span class="comment">// If `None`, the runtime is shutting down, so there is no need to signal shutdown |
| </span><span class="kw">if let </span><span class="prelude-val">Some</span>(core) = core.as_mut() { |
| core.unhandled_panic = <span class="bool-val">true</span>; |
| <span class="self">self</span>.shared.owned.close_and_shutdown_all(); |
| } |
| } |
| <span class="kw">_ </span>=> <span class="macro">unreachable!</span>(<span class="string">"runtime core not set in CURRENT thread-local"</span>), |
| }) |
| } |
| } |
| } |
| } |
| } |
| |
| <span class="kw">impl </span>Wake <span class="kw">for </span>Handle { |
| <span class="kw">fn </span>wake(arc_self: Arc<<span class="self">Self</span>>) { |
| Wake::wake_by_ref(<span class="kw-2">&</span>arc_self) |
| } |
| |
| <span class="doccomment">/// Wake by reference |
| </span><span class="kw">fn </span>wake_by_ref(arc_self: <span class="kw-2">&</span>Arc<<span class="self">Self</span>>) { |
| arc_self.shared.woken.store(<span class="bool-val">true</span>, Release); |
| arc_self.driver.unpark(); |
| } |
| } |
| |
| <span class="comment">// ===== CoreGuard ===== |
| |
| </span><span class="doccomment">/// Used to ensure we always place the `Core` value back into its slot in |
| /// `CurrentThread`, even if the future panics. |
| </span><span class="kw">struct </span>CoreGuard<<span class="lifetime">'a</span>> { |
| context: Context, |
| scheduler: <span class="kw-2">&</span><span class="lifetime">'a </span>CurrentThread, |
| } |
| |
| <span class="kw">impl </span>CoreGuard<<span class="lifetime">'_</span>> { |
| <span class="attribute">#[track_caller] |
| </span><span class="kw">fn </span>block_on<F: Future>(<span class="self">self</span>, future: F) -> F::Output { |
| <span class="kw">let </span>ret = <span class="self">self</span>.enter(|<span class="kw-2">mut </span>core, context| { |
| <span class="kw">let </span>waker = Handle::waker_ref(<span class="kw-2">&</span>context.handle); |
| <span class="kw">let </span><span class="kw-2">mut </span>cx = std::task::Context::from_waker(<span class="kw-2">&</span>waker); |
| |
| <span class="macro">pin!</span>(future); |
| |
| <span class="lifetime">'outer</span>: <span class="kw">loop </span>{ |
| <span class="kw">let </span>handle = <span class="kw-2">&</span>context.handle; |
| |
| <span class="kw">if </span>handle.reset_woken() { |
| <span class="kw">let </span>(c, res) = context.enter(core, || { |
| <span class="kw">crate</span>::runtime::coop::budget(|| future.as_mut().poll(<span class="kw-2">&mut </span>cx)) |
| }); |
| |
| core = c; |
| |
| <span class="kw">if let </span>Ready(v) = res { |
| <span class="kw">return </span>(core, <span class="prelude-val">Some</span>(v)); |
| } |
| } |
| |
| <span class="kw">for _ in </span><span class="number">0</span>..handle.shared.config.event_interval { |
| <span class="comment">// Make sure we didn't hit an unhandled_panic |
| </span><span class="kw">if </span>core.unhandled_panic { |
| <span class="kw">return </span>(core, <span class="prelude-val">None</span>); |
| } |
| |
| <span class="comment">// Get and increment the current tick |
| </span><span class="kw">let </span>tick = core.tick; |
| core.tick = core.tick.wrapping_add(<span class="number">1</span>); |
| |
| <span class="kw">let </span>entry = <span class="kw">if </span>tick % handle.shared.config.global_queue_interval == <span class="number">0 </span>{ |
| handle.pop().or_else(|| core.tasks.pop_front()) |
| } <span class="kw">else </span>{ |
| core.tasks.pop_front().or_else(|| handle.pop()) |
| }; |
| |
| <span class="kw">let </span>task = <span class="kw">match </span>entry { |
| <span class="prelude-val">Some</span>(entry) => entry, |
| <span class="prelude-val">None </span>=> { |
| core = <span class="kw">if </span>did_defer_tasks() { |
| context.park_yield(core, handle) |
| } <span class="kw">else </span>{ |
| context.park(core, handle) |
| }; |
| |
| <span class="comment">// Try polling the `block_on` future next |
| </span><span class="kw">continue </span><span class="lifetime">'outer</span>; |
| } |
| }; |
| |
| <span class="kw">let </span>task = context.handle.shared.owned.assert_owner(task); |
| |
| <span class="kw">let </span>(c, <span class="kw">_</span>) = context.run_task(core, || { |
| task.run(); |
| }); |
| |
| core = c; |
| } |
| |
| <span class="comment">// Yield to the driver, this drives the timer and pulls any |
| // pending I/O events. |
| </span>core = context.park_yield(core, handle); |
| } |
| }); |
| |
| <span class="kw">match </span>ret { |
| <span class="prelude-val">Some</span>(ret) => ret, |
| <span class="prelude-val">None </span>=> { |
| <span class="comment">// `block_on` panicked. |
| </span><span class="macro">panic!</span>(<span class="string">"a spawned task panicked and the runtime is configured to shut down on unhandled panic"</span>); |
| } |
| } |
| } |
| |
| <span class="doccomment">/// Enters the scheduler context. This sets the queue and other necessary |
| /// scheduler state in the thread-local. |
| </span><span class="kw">fn </span>enter<F, R>(<span class="self">self</span>, f: F) -> R |
| <span class="kw">where |
| </span>F: FnOnce(Box<Core>, <span class="kw-2">&</span>Context) -> (Box<Core>, R), |
| { |
| <span class="comment">// Remove `core` from `context` to pass into the closure. |
| </span><span class="kw">let </span>core = <span class="self">self</span>.context.core.borrow_mut().take().expect(<span class="string">"core missing"</span>); |
| |
| <span class="comment">// Call the closure and place `core` back |
| </span><span class="kw">let </span>(core, ret) = CURRENT.set(<span class="kw-2">&</span><span class="self">self</span>.context, || f(core, <span class="kw-2">&</span><span class="self">self</span>.context)); |
| |
| <span class="kw-2">*</span><span class="self">self</span>.context.core.borrow_mut() = <span class="prelude-val">Some</span>(core); |
| |
| ret |
| } |
| } |
| |
| <span class="kw">impl </span>Drop <span class="kw">for </span>CoreGuard<<span class="lifetime">'_</span>> { |
| <span class="kw">fn </span>drop(<span class="kw-2">&mut </span><span class="self">self</span>) { |
| <span class="kw">if let </span><span class="prelude-val">Some</span>(core) = <span class="self">self</span>.context.core.borrow_mut().take() { |
| <span class="comment">// Replace old scheduler back into the state to allow |
| // other threads to pick it up and drive it. |
| </span><span class="self">self</span>.scheduler.core.set(core); |
| |
| <span class="comment">// Wake up other possible threads that could steal the driver. |
| </span><span class="self">self</span>.scheduler.notify.notify_one() |
| } |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../../" data-current-crate="tokio" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |