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use crate::thread_manager::{DynamicPoolManager, DynamicRunner};
use crossbeam_channel::{unbounded, Receiver, Sender};
use lazy_static::lazy_static;
use lightproc::lightproc::LightProc;
use lightproc::proc_stack::ProcStack;
use lightproc::recoverable_handle::RecoverableHandle;
use once_cell::sync::{Lazy, OnceCell};
use std::future::Future;
use std::iter::Iterator;
use std::sync::Arc;
use std::time::Duration;
use std::{env, thread};
use tracing::trace;
const DEFAULT_LOW_WATERMARK: u64 = 2;
const THREAD_RECV_TIMEOUT: Duration = Duration::from_millis(100);
pub fn spawn_blocking<F, R>(future: F, stack: ProcStack) -> RecoverableHandle<R>
where
F: Future<Output = R> + Send + 'static,
R: Send + 'static,
{
let (task, handle) = LightProc::recoverable(future, schedule, stack);
task.schedule();
handle
}
struct BlockingRunner {}
impl DynamicRunner for BlockingRunner {
fn run_static(&self, park_timeout: Duration) -> ! {
loop {
while let Ok(task) = POOL.receiver.recv_timeout(THREAD_RECV_TIMEOUT) {
trace!("static thread: running task");
task.run();
}
trace!("static: empty queue, parking with timeout");
thread::park_timeout(park_timeout);
}
}
fn run_dynamic(&self, parker: &dyn Fn()) -> ! {
loop {
while let Ok(task) = POOL.receiver.recv_timeout(THREAD_RECV_TIMEOUT) {
trace!("dynamic thread: running task");
task.run();
}
trace!(
"dynamic thread: parking - {:?}",
std::thread::current().id()
);
parker();
}
}
fn run_standalone(&self) {
while let Ok(task) = POOL.receiver.recv_timeout(THREAD_RECV_TIMEOUT) {
task.run();
}
trace!("standalone thread: quitting.");
}
}
struct Pool {
sender: Sender<LightProc>,
receiver: Receiver<LightProc>,
}
static DYNAMIC_POOL_MANAGER: OnceCell<DynamicPoolManager> = OnceCell::new();
static POOL: Lazy<Pool> = Lazy::new(|| {
let runner = Arc::new(BlockingRunner {});
DYNAMIC_POOL_MANAGER
.set(DynamicPoolManager::new(*low_watermark() as usize, runner))
.expect("couldn't create dynamic pool manager");
DYNAMIC_POOL_MANAGER
.get()
.expect("couldn't get static pool manager")
.initialize();
let (sender, receiver) = unbounded();
Pool { sender, receiver }
});
fn schedule(t: LightProc) {
if let Err(err) = POOL.sender.try_send(t) {
POOL.sender.send(err.into_inner()).unwrap();
}
DYNAMIC_POOL_MANAGER.get().unwrap().increment_frequency();
}
#[inline]
fn low_watermark() -> &'static u64 {
lazy_static! {
static ref LOW_WATERMARK: u64 = {
env::var_os("BASTION_BLOCKING_THREADS")
.map(|x| x.to_str().unwrap().parse::<u64>().unwrap())
.unwrap_or(DEFAULT_LOW_WATERMARK)
};
}
&*LOW_WATERMARK
}