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Code Issues Releases Wiki Activity

refactor connection counter (#343)

Browse Source 
* Remove restart_worker test

* Remove Slab

* Rework counter

* Make counter limit switch accurate

* Remove backpressure. Add pause state

* make changes for review

* fix doc comment for counter
This commit is contained in:
fakeshadow 2021-04-29 23:27:08 +08:00 committed by GitHub
parent 8ad5f58d38
commit e4d4ae21ee
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6 changed files with 359 additions and 314 deletions
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1
actix-server/Cargo.toml
View File

@ -28,7 +28,6 @@ futures-core = { version = "0.3.7", default-features = false, features = ["alloc
log = "0.4"
mio = { version = "0.7.6", features = ["os-poll", "net"] }
num_cpus = "1.13"
slab = "0.4"
tokio = { version = "1.2", features = ["sync"] }
[dev-dependencies]

377
actix-server/src/accept.rs
View File

@ -7,18 +7,14 @@ use actix_rt::{
};
use log::{error, info};
use mio::{Interest, Poll, Token as MioToken};
use slab::Slab;
use crate::server::Server;
use crate::socket::MioListener;
use crate::waker_queue::{WakerInterest, WakerQueue, WAKER_TOKEN};
use crate::worker::{Conn, WorkerHandleAccept};
use crate::Token;
struct ServerSocketInfo {
/// Beware this is the crate token for identify socket and should not be confused
/// with `mio::Token`.
token: Token,
token: usize,
lst: MioListener,
@ -62,7 +58,7 @@ impl AcceptLoop {
pub(crate) fn start(
&mut self,
socks: Vec<(Token, MioListener)>,
socks: Vec<(usize, MioListener)>,
handles: Vec<WorkerHandleAccept>,
) {
let srv = self.srv.take().expect("Can not re-use AcceptInfo");
@ -81,7 +77,7 @@ struct Accept {
srv: Server,
next: usize,
avail: Availability,
backpressure: bool,
paused: bool,
}
/// Array of u128 with every bit as marker for a worker handle's availability.
@ -95,23 +91,22 @@ impl Default for Availability {
impl Availability {
/// Check if any worker handle is available
#[inline(always)]
fn available(&self) -> bool {
self.0.iter().any(|a| *a != 0)
}
/// Check if worker handle is available by index
#[inline(always)]
fn get_available(&self, idx: usize) -> bool {
let (offset, idx) = Self::offset(idx);
self.0[offset] & (1 << idx as u128) != 0
}
/// Set worker handle available state by index.
fn set_available(&mut self, idx: usize, avail: bool) {
let (offset, idx) = if idx < 128 {
(0, idx)
} else if idx < 128 * 2 {
(1, idx - 128)
} else if idx < 128 * 3 {
(2, idx - 128 * 2)
} else if idx < 128 * 4 {
(3, idx - 128 * 3)
} else {
panic!("Max WorkerHandle count is 512")
};
let (offset, idx) = Self::offset(idx);
let off = 1 << idx as u128;
if avail {
@ -128,6 +123,21 @@ impl Availability {
self.set_available(handle.idx(), true);
})
}
/// Get offset and adjusted index of given worker handle index.
fn offset(idx: usize) -> (usize, usize) {
if idx < 128 {
(0, idx)
} else if idx < 128 * 2 {
(1, idx - 128)
} else if idx < 128 * 3 {
(2, idx - 128 * 2)
} else if idx < 128 * 4 {
(3, idx - 128 * 3)
} else {
panic!("Max WorkerHandle count is 512")
}
}
}
/// This function defines errors that are per-connection. Which basically
@ -147,7 +157,7 @@ impl Accept {
pub(crate) fn start(
poll: Poll,
waker: WakerQueue,
socks: Vec<(Token, MioListener)>,
socks: Vec<(usize, MioListener)>,
srv: Server,
handles: Vec<WorkerHandleAccept>,
) {
@ -158,10 +168,10 @@ impl Accept {
.name("actix-server accept loop".to_owned())
.spawn(move || {
System::set_current(sys);
let (mut accept, sockets) =
let (mut accept, mut sockets) =
Accept::new_with_sockets(poll, waker, socks, handles, srv);
accept.poll_with(sockets);
accept.poll_with(&mut sockets);
})
.unwrap();
}
@ -169,26 +179,25 @@ impl Accept {
fn new_with_sockets(
poll: Poll,
waker: WakerQueue,
socks: Vec<(Token, MioListener)>,
socks: Vec<(usize, MioListener)>,
handles: Vec<WorkerHandleAccept>,
srv: Server,
) -> (Accept, Slab<ServerSocketInfo>) {
let mut sockets = Slab::new();
for (hnd_token, mut lst) in socks.into_iter() {
let entry = sockets.vacant_entry();
let token = entry.key();
) -> (Accept, Vec<ServerSocketInfo>) {
let sockets = socks
.into_iter()
.map(|(token, mut lst)| {
// Start listening for incoming connections
poll.registry()
.register(&mut lst, MioToken(token), Interest::READABLE)
.unwrap_or_else(|e| panic!("Can not register io: {}", e));
// Start listening for incoming connections
poll.registry()
.register(&mut lst, MioToken(token), Interest::READABLE)
.unwrap_or_else(|e| panic!("Can not register io: {}", e));
entry.insert(ServerSocketInfo {
token: hnd_token,
lst,
timeout: None,
});
}
ServerSocketInfo {
token,
lst,
timeout: None,
}
})
.collect();
let mut avail = Availability::default();
@ -202,19 +211,19 @@ impl Accept {
srv,
next: 0,
avail,
backpressure: false,
paused: false,
};
(accept, sockets)
}
fn poll_with(&mut self, mut sockets: Slab<ServerSocketInfo>) {
fn poll_with(&mut self, sockets: &mut [ServerSocketInfo]) {
let mut events = mio::Events::with_capacity(128);
loop {
if let Err(e) = self.poll.poll(&mut events, None) {
match e.kind() {
std::io::ErrorKind::Interrupted => continue,
io::ErrorKind::Interrupted => continue,
_ => panic!("Poll error: {}", e),
}
}
@ -222,122 +231,146 @@ impl Accept {
for event in events.iter() {
let token = event.token();
match token {
// This is a loop because interests for command from previous version was
// a loop that would try to drain the command channel. It's yet unknown
// if it's necessary/good practice to actively drain the waker queue.
WAKER_TOKEN => 'waker: loop {
// take guard with every iteration so no new interest can be added
// until the current task is done.
let mut guard = self.waker.guard();
match guard.pop_front() {
// worker notify it becomes available. we may want to recover
// from backpressure.
Some(WakerInterest::WorkerAvailable(idx)) => {
drop(guard);
self.maybe_backpressure(&mut sockets, false);
self.avail.set_available(idx, true);
}
// a new worker thread is made and it's handle would be added to Accept
Some(WakerInterest::Worker(handle)) => {
drop(guard);
// maybe we want to recover from a backpressure.
self.maybe_backpressure(&mut sockets, false);
self.avail.set_available(handle.idx(), true);
self.handles.push(handle);
}
// got timer interest and it's time to try register socket(s) again
Some(WakerInterest::Timer) => {
drop(guard);
self.process_timer(&mut sockets)
}
Some(WakerInterest::Pause) => {
drop(guard);
self.deregister_all(&mut sockets);
}
Some(WakerInterest::Resume) => {
drop(guard);
sockets.iter_mut().for_each(|(token, info)| {
self.register_logged(token, info);
});
}
Some(WakerInterest::Stop) => {
return self.deregister_all(&mut sockets);
}
// waker queue is drained
None => {
// Reset the WakerQueue before break so it does not grow infinitely
WakerQueue::reset(&mut guard);
break 'waker;
}
WAKER_TOKEN => {
let exit = self.handle_waker(sockets);
if exit {
info!("Accept is stopped.");
return;
}
},
}
_ => {
let token = usize::from(token);
self.accept(&mut sockets, token);
self.accept(sockets, token);
}
}
}
}
}
fn process_timer(&self, sockets: &mut Slab<ServerSocketInfo>) {
fn handle_waker(&mut self, sockets: &mut [ServerSocketInfo]) -> bool {
// This is a loop because interests for command from previous version was
// a loop that would try to drain the command channel. It's yet unknown
// if it's necessary/good practice to actively drain the waker queue.
loop {
// take guard with every iteration so no new interest can be added
// until the current task is done.
let mut guard = self.waker.guard();
match guard.pop_front() {
// worker notify it becomes available.
Some(WakerInterest::WorkerAvailable(idx)) => {
drop(guard);
self.avail.set_available(idx, true);
if !self.paused {
self.accept_all(sockets);
}
}
// a new worker thread is made and it's handle would be added to Accept
Some(WakerInterest::Worker(handle)) => {
drop(guard);
self.avail.set_available(handle.idx(), true);
self.handles.push(handle);
if !self.paused {
self.accept_all(sockets);
}
}
// got timer interest and it's time to try register socket(s) again
Some(WakerInterest::Timer) => {
drop(guard);
self.process_timer(sockets)
}
Some(WakerInterest::Pause) => {
drop(guard);
self.paused = true;
self.deregister_all(sockets);
}
Some(WakerInterest::Resume) => {
drop(guard);
self.paused = false;
sockets.iter_mut().for_each(|info| {
self.register_logged(info);
});
self.accept_all(sockets);
}
Some(WakerInterest::Stop) => {
self.deregister_all(sockets);
return true;
}
// waker queue is drained
None => {
// Reset the WakerQueue before break so it does not grow infinitely
WakerQueue::reset(&mut guard);
return false;
}
}
}
}
fn process_timer(&self, sockets: &mut [ServerSocketInfo]) {
let now = Instant::now();
sockets
.iter_mut()
// Only sockets that had an associated timeout were deregistered.
.filter(|(_, info)| info.timeout.is_some())
.for_each(|(token, info)| {
.filter(|info| info.timeout.is_some())
.for_each(|info| {
let inst = info.timeout.take().unwrap();
if now < inst {
info.timeout = Some(inst);
} else if !self.backpressure {
self.register_logged(token, info);
} else if !self.paused {
self.register_logged(info);
}
// Drop the timeout if server is in backpressure and socket timeout is expired.
// When server recovers from backpressure it will register all sockets without
// Drop the timeout if server is paused and socket timeout is expired.
// When server recovers from pause it will register all sockets without
// a timeout value so this socket register will be delayed till then.
});
}
#[cfg(not(target_os = "windows"))]
fn register(&self, token: usize, info: &mut ServerSocketInfo) -> io::Result<()> {
fn register(&self, info: &mut ServerSocketInfo) -> io::Result<()> {
let token = MioToken(info.token);
self.poll
.registry()
.register(&mut info.lst, MioToken(token), Interest::READABLE)
.register(&mut info.lst, token, Interest::READABLE)
}
#[cfg(target_os = "windows")]
fn register(&self, token: usize, info: &mut ServerSocketInfo) -> io::Result<()> {
fn register(&self, info: &mut ServerSocketInfo) -> io::Result<()> {
// On windows, calling register without deregister cause an error.
// See https://github.com/actix/actix-web/issues/905
// Calling reregister seems to fix the issue.
let token = MioToken(info.token);
self.poll
.registry()
.register(&mut info.lst, mio::Token(token), Interest::READABLE)
.register(&mut info.lst, token, Interest::READABLE)
.or_else(|_| {
self.poll.registry().reregister(
&mut info.lst,
mio::Token(token),
Interest::READABLE,
)
self.poll
.registry()
.reregister(&mut info.lst, token, Interest::READABLE)
})
}
fn register_logged(&self, token: usize, info: &mut ServerSocketInfo) {
match self.register(token, info) {
fn register_logged(&self, info: &mut ServerSocketInfo) {
match self.register(info) {
Ok(_) => info!("Resume accepting connections on {}", info.lst.local_addr()),
Err(e) => error!("Can not register server socket {}", e),
}
}
fn deregister(&self, info: &mut ServerSocketInfo) -> io::Result<()> {
self.poll.registry().deregister(&mut info.lst)
}
fn deregister_logged(&self, info: &mut ServerSocketInfo) {
match self.deregister(info) {
match self.poll.registry().deregister(&mut info.lst) {
Ok(_) => info!("Paused accepting connections on {}", info.lst.local_addr()),
Err(e) => {
error!("Can not deregister server socket {}", e)
@ -345,7 +378,7 @@ impl Accept {
}
}
fn deregister_all(&self, sockets: &mut Slab<ServerSocketInfo>) {
fn deregister_all(&self, sockets: &mut [ServerSocketInfo]) {
// This is a best effort implementation with following limitation:
//
// Every ServerSocketInfo with associate timeout will be skipped and it's timeout
@ -358,70 +391,23 @@ impl Accept {
.iter_mut()
// Take all timeout.
// This is to prevent Accept::process_timer method re-register a socket afterwards.
.map(|(_, info)| (info.timeout.take(), info))
.map(|info| (info.timeout.take(), info))
// Socket info with a timeout is already deregistered so skip them.
.filter(|(timeout, _)| timeout.is_none())
.for_each(|(_, info)| self.deregister_logged(info));
}
fn maybe_backpressure(&mut self, sockets: &mut Slab<ServerSocketInfo>, on: bool) {
// Only operate when server is in a different backpressure than the given flag.
if self.backpressure != on {
self.backpressure = on;
sockets
.iter_mut()
// Only operate on sockets without associated timeout.
// Sockets with it should be handled by `accept` and `process_timer` methods.
// They are already deregistered or need to be reregister in the future.
.filter(|(_, info)| info.timeout.is_none())
.for_each(|(token, info)| {
if on {
self.deregister_logged(info);
} else {
self.register_logged(token, info);
}
});
}
}
fn accept_one(&mut self, sockets: &mut Slab<ServerSocketInfo>, mut conn: Conn) {
if self.backpressure {
// send_connection would remove fault worker from handles.
// worst case here is conn get dropped after all handles are gone.
while let Err(c) = self.send_connection(sockets, conn) {
conn = c
}
} else {
while self.avail.available() {
let next = self.next();
let idx = next.idx();
if next.available() {
self.avail.set_available(idx, true);
match self.send_connection(sockets, conn) {
Ok(_) => return,
Err(c) => conn = c,
}
} else {
self.avail.set_available(idx, false);
self.set_next();
}
}
// Sending Conn failed due to either all workers are in error or not available.
// Enter backpressure state and try again.
self.maybe_backpressure(sockets, true);
self.accept_one(sockets, conn);
}
}
// Send connection to worker and handle error.
fn send_connection(
&mut self,
sockets: &mut Slab<ServerSocketInfo>,
conn: Conn,
) -> Result<(), Conn> {
match self.next().send(conn) {
fn send_connection(&mut self, conn: Conn) -> Result<(), Conn> {
let next = self.next();
match next.send(conn) {
Ok(_) => {
// Increment counter of WorkerHandle.
// Set worker to unavailable with it hit max (Return false).
if !next.inc_counter() {
let idx = next.idx();
self.avail.set_available(idx, false);
}
self.set_next();
Ok(())
}
@ -432,7 +418,6 @@ impl Accept {
if self.handles.is_empty() {
error!("No workers");
self.maybe_backpressure(sockets, true);
// All workers are gone and Conn is nowhere to be sent.
// Treat this situation as Ok and drop Conn.
return Ok(());
@ -445,19 +430,38 @@ impl Accept {
}
}
fn accept(&mut self, sockets: &mut Slab<ServerSocketInfo>, token: usize) {
fn accept_one(&mut self, mut conn: Conn) {
loop {
let info = sockets
.get_mut(token)
.expect("ServerSocketInfo is removed from Slab");
let next = self.next();
let idx = next.idx();
if self.avail.get_available(idx) {
match self.send_connection(conn) {
Ok(_) => return,
Err(c) => conn = c,
}
} else {
self.avail.set_available(idx, false);
self.set_next();
if !self.avail.available() {
while let Err(c) = self.send_connection(conn) {
conn = c;
}
return;
}
}
}
}
fn accept(&mut self, sockets: &mut [ServerSocketInfo], token: usize) {
while self.avail.available() {
let info = &mut sockets[token];
match info.lst.accept() {
Ok(io) => {
let msg = Conn {
io,
token: info.token,
};
self.accept_one(sockets, msg);
let conn = Conn { io, token };
self.accept_one(conn);
}
Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => return,
Err(ref e) if connection_error(e) => continue,
@ -485,11 +489,22 @@ impl Accept {
}
}
fn accept_all(&mut self, sockets: &mut [ServerSocketInfo]) {
sockets
.iter_mut()
.map(|info| info.token)
.collect::<Vec<_>>()
.into_iter()
.for_each(|idx| self.accept(sockets, idx))
}
#[inline(always)]
fn next(&self) -> &WorkerHandleAccept {
&self.handles[self.next]
}
/// Set next worker handle that would accept connection.
#[inline(always)]
fn set_next(&mut self) {
self.next = (self.next + 1) % self.handles.len();
}

36
actix-server/src/builder.rs
View File

@ -8,30 +8,29 @@ use std::{
use actix_rt::{self as rt, net::TcpStream, time::sleep, System};
use log::{error, info};
use tokio::sync::mpsc::{unbounded_channel, UnboundedReceiver};
use tokio::sync::oneshot;
use tokio::sync::{
mpsc::{unbounded_channel, UnboundedReceiver},
oneshot,
};
use crate::accept::AcceptLoop;
use crate::join_all;
use crate::server::{Server, ServerCommand};
use crate::service::{InternalServiceFactory, ServiceFactory, StreamNewService};
use crate::signals::{Signal, Signals};
use crate::socket::{MioListener, StdSocketAddr, StdTcpListener, ToSocketAddrs};
use crate::socket::{MioTcpListener, MioTcpSocket};
use crate::waker_queue::{WakerInterest, WakerQueue};
use crate::worker::{
ServerWorker, ServerWorkerConfig, WorkerAvailability, WorkerHandleAccept,
WorkerHandleServer,
};
use crate::{join_all, Token};
use crate::worker::{ServerWorker, ServerWorkerConfig, WorkerHandleAccept, WorkerHandleServer};
/// Server builder
pub struct ServerBuilder {
threads: usize,
token: Token,
token: usize,
backlog: u32,
handles: Vec<(usize, WorkerHandleServer)>,
services: Vec<Box<dyn InternalServiceFactory>>,
sockets: Vec<(Token, String, MioListener)>,
sockets: Vec<(usize, String, MioListener)>,
accept: AcceptLoop,
exit: bool,
no_signals: bool,
@ -55,7 +54,7 @@ impl ServerBuilder {
ServerBuilder {
threads: num_cpus::get(),
token: Token::default(),
token: 0,
handles: Vec::new(),
services: Vec::new(),
sockets: Vec::new(),
@ -157,7 +156,7 @@ impl ServerBuilder {
let sockets = bind_addr(addr, self.backlog)?;
for lst in sockets {
let token = self.token.next();
let token = self.next_token();
self.services.push(StreamNewService::create(
name.as_ref().to_string(),
token,
@ -206,7 +205,7 @@ impl ServerBuilder {
{
use std::net::{IpAddr, Ipv4Addr};
lst.set_nonblocking(true)?;
let token = self.token.next();
let token = self.next_token();
let addr = StdSocketAddr::new(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)), 8080);
self.services.push(StreamNewService::create(
name.as_ref().to_string(),
@ -232,7 +231,7 @@ impl ServerBuilder {
lst.set_nonblocking(true)?;
let addr = lst.local_addr()?;
let token = self.token.next();
let token = self.next_token();
self.services.push(StreamNewService::create(
name.as_ref().to_string(),
token,
@ -291,12 +290,11 @@ impl ServerBuilder {
fn start_worker(
&self,
idx: usize,
waker: WakerQueue,
waker_queue: WakerQueue,
) -> (WorkerHandleAccept, WorkerHandleServer) {
let avail = WorkerAvailability::new(idx, waker);
let services = self.services.iter().map(|v| v.clone_factory()).collect();
ServerWorker::start(idx, services, avail, self.worker_config)
ServerWorker::start(idx, services, waker_queue, self.worker_config)
}
fn handle_cmd(&mut self, item: ServerCommand) {
@ -410,6 +408,12 @@ impl ServerBuilder {
}
}
}
fn next_token(&mut self) -> usize {
let token = self.token;
self.token += 1;
token
}
}
impl Future for ServerBuilder {

22
actix-server/src/lib.rs
View File

@ -26,28 +26,6 @@ use std::future::Future;
use std::pin::Pin;
use std::task::{Context, Poll};
/// Socket ID token
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub(crate) struct Token(usize);
impl Default for Token {
fn default() -> Self {
Self::new()
}
}
impl Token {
fn new() -> Self {
Self(0)
}
pub(crate) fn next(&mut self) -> Token {
let token = Token(self.0);
self.0 += 1;
token
}
}
/// Start server building process
pub fn new() -> ServerBuilder {
ServerBuilder::default()

25
actix-server/src/service.rs
View File

@ -3,15 +3,12 @@ use std::net::SocketAddr;
use std::task::{Context, Poll};
use actix_service::{Service, ServiceFactory as BaseServiceFactory};
use actix_utils::{
counter::CounterGuard,
future::{ready, Ready},
};
use actix_utils::future::{ready, Ready};
use futures_core::future::LocalBoxFuture;
use log::error;
use crate::socket::{FromStream, MioStream};
use crate::Token;
use crate::worker::WorkerCounterGuard;
pub trait ServiceFactory<Stream: FromStream>: Send + Clone + 'static {
type Factory: BaseServiceFactory<Stream, Config = ()>;
@ -20,16 +17,16 @@ pub trait ServiceFactory<Stream: FromStream>: Send + Clone + 'static {
}
pub(crate) trait InternalServiceFactory: Send {
fn name(&self, token: Token) -> &str;
fn name(&self, token: usize) -> &str;
fn clone_factory(&self) -> Box<dyn InternalServiceFactory>;
fn create(&self) -> LocalBoxFuture<'static, Result<(Token, BoxedServerService), ()>>;
fn create(&self) -> LocalBoxFuture<'static, Result<(usize, BoxedServerService), ()>>;
}
pub(crate) type BoxedServerService = Box<
dyn Service<
(CounterGuard, MioStream),
(WorkerCounterGuard, MioStream),
Response = (),
Error = (),
Future = Ready<Result<(), ()>>,
@ -50,7 +47,7 @@ impl<S, I> StreamService<S, I> {
}
}
impl<S, I> Service<(CounterGuard, MioStream)> for StreamService<S, I>
impl<S, I> Service<(WorkerCounterGuard, MioStream)> for StreamService<S, I>
where
S: Service<I>,
S::Future: 'static,
@ -65,7 +62,7 @@ where
self.service.poll_ready(ctx).map_err(|_| ())
}
fn call(&self, (guard, req): (CounterGuard, MioStream)) -> Self::Future {
fn call(&self, (guard, req): (WorkerCounterGuard, MioStream)) -> Self::Future {
ready(match FromStream::from_mio(req) {
Ok(stream) => {
let f = self.service.call(stream);
@ -86,7 +83,7 @@ where
pub(crate) struct StreamNewService<F: ServiceFactory<Io>, Io: FromStream> {
name: String,
inner: F,
token: Token,
token: usize,
addr: SocketAddr,
_t: PhantomData<Io>,
}
@ -98,7 +95,7 @@ where
{
pub(crate) fn create(
name: String,
token: Token,
token: usize,
inner: F,
addr: SocketAddr,
) -> Box<dyn InternalServiceFactory> {
@ -117,7 +114,7 @@ where
F: ServiceFactory<Io>,
Io: FromStream + Send + 'static,
{
fn name(&self, _: Token) -> &str {
fn name(&self, _: usize) -> &str {
&self.name
}
@ -131,7 +128,7 @@ where
})
}
fn create(&self) -> LocalBoxFuture<'static, Result<(Token, BoxedServerService), ()>> {
fn create(&self) -> LocalBoxFuture<'static, Result<(usize, BoxedServerService), ()>> {
let token = self.token;
let fut = self.inner.create().new_service(());
Box::pin(async move {

212
actix-server/src/worker.rs
View File

@ -2,8 +2,9 @@ use std::{
future::Future,
mem,
pin::Pin,
rc::Rc,
sync::{
atomic::{AtomicBool, Ordering},
atomic::{AtomicUsize, Ordering},
Arc,
},
task::{Context, Poll},
@ -15,7 +16,6 @@ use actix_rt::{
time::{sleep, Instant, Sleep},
Arbiter,
};
use actix_utils::counter::Counter;
use futures_core::{future::LocalBoxFuture, ready};
use log::{error, info, trace};
use tokio::sync::{
@ -23,10 +23,10 @@ use tokio::sync::{
oneshot,
};
use crate::join_all;
use crate::service::{BoxedServerService, InternalServiceFactory};
use crate::socket::MioStream;
use crate::waker_queue::{WakerInterest, WakerQueue};
use crate::{join_all, Token};
/// Stop worker message. Returns `true` on successful graceful shutdown.
/// and `false` if some connections still alive when shutdown execute.
@ -38,35 +38,131 @@ pub(crate) struct Stop {
#[derive(Debug)]
pub(crate) struct Conn {
pub io: MioStream,
pub token: Token,
pub token: usize,
}
fn handle_pair(
idx: usize,
tx1: UnboundedSender<Conn>,
tx2: UnboundedSender<Stop>,
avail: WorkerAvailability,
counter: Counter,
) -> (WorkerHandleAccept, WorkerHandleServer) {
let accept = WorkerHandleAccept { tx: tx1, avail };
let accept = WorkerHandleAccept {
idx,
tx: tx1,
counter,
};
let server = WorkerHandleServer { idx, tx: tx2 };
(accept, server)
}
/// counter: Arc<AtomicUsize> field is owned by `Accept` thread and `ServerWorker` thread.
///
/// `Accept` would increment the counter and `ServerWorker` would decrement it.
///
/// # Atomic Ordering:
///
/// `Accept` always look into it's cached `Availability` field for `ServerWorker` state.
/// It lazily increment counter after successful dispatching new work to `ServerWorker`.
/// On reaching counter limit `Accept` update it's cached `Availability` and mark worker as
/// unable to accept any work.
///
/// `ServerWorker` always decrement the counter when every work received from `Accept` is done.
/// On reaching counter limit worker would use `mio::Waker` and `WakerQueue` to wake up `Accept`
/// and notify it to update cached `Availability` again to mark worker as able to accept work again.
///
/// Hense a wake up would only happen after `Accept` increment it to limit.
/// And a decrement to limit always wake up `Accept`.
#[derive(Clone)]
pub(crate) struct Counter {
counter: Arc<AtomicUsize>,
limit: usize,
}
impl Counter {
pub(crate) fn new(limit: usize) -> Self {
Self {
counter: Arc::new(AtomicUsize::new(1)),
limit,
}
}
/// Increment counter by 1 and return true when hitting limit
#[inline(always)]
pub(crate) fn inc(&self) -> bool {
self.counter.fetch_add(1, Ordering::Relaxed) != self.limit
}
/// Decrement counter by 1 and return true if crossing limit.
#[inline(always)]
pub(crate) fn dec(&self) -> bool {
self.counter.fetch_sub(1, Ordering::Relaxed) == self.limit
}
pub(crate) fn total(&self) -> usize {
self.counter.load(Ordering::SeqCst) - 1
}
}
pub(crate) struct WorkerCounter {
idx: usize,
inner: Rc<(WakerQueue, Counter)>,
}
impl Clone for WorkerCounter {
fn clone(&self) -> Self {
Self {
idx: self.idx,
inner: self.inner.clone(),
}
}
}
impl WorkerCounter {
pub(crate) fn new(idx: usize, waker_queue: WakerQueue, counter: Counter) -> Self {
Self {
idx,
inner: Rc::new((waker_queue, counter)),
}
}
#[inline(always)]
pub(crate) fn guard(&self) -> WorkerCounterGuard {
WorkerCounterGuard(self.clone())
}
fn total(&self) -> usize {
self.inner.1.total()
}
}
pub(crate) struct WorkerCounterGuard(WorkerCounter);
impl Drop for WorkerCounterGuard {
fn drop(&mut self) {
let (waker_queue, counter) = &*self.0.inner;
if counter.dec() {
waker_queue.wake(WakerInterest::WorkerAvailable(self.0.idx));
}
}
}
/// Handle to worker that can send connection message to worker and share the
/// availability of worker to other thread.
///
/// Held by [Accept](crate::accept::Accept).
pub(crate) struct WorkerHandleAccept {
idx: usize,
tx: UnboundedSender<Conn>,
avail: WorkerAvailability,
counter: Counter,
}
impl WorkerHandleAccept {
#[inline(always)]
pub(crate) fn idx(&self) -> usize {
self.avail.idx
self.idx
}
#[inline(always)]
@ -75,8 +171,8 @@ impl WorkerHandleAccept {
}
#[inline(always)]
pub(crate) fn available(&self) -> bool {
self.avail.available()
pub(crate) fn inc_counter(&self) -> bool {
self.counter.inc()
}
}
@ -96,40 +192,6 @@ impl WorkerHandleServer {
}
}
#[derive(Clone)]
pub(crate) struct WorkerAvailability {
idx: usize,
waker: WakerQueue,
available: Arc<AtomicBool>,
}
impl WorkerAvailability {
pub fn new(idx: usize, waker: WakerQueue) -> Self {
WorkerAvailability {
idx,
waker,
available: Arc::new(AtomicBool::new(false)),
}
}
#[inline(always)]
pub fn available(&self) -> bool {
self.available.load(Ordering::Acquire)
}
pub fn set(&self, val: bool) {
// Ordering:
//
// There could be multiple set calls happen in one <ServerWorker as Future>::poll.
// Order is important between them.
let old = self.available.swap(val, Ordering::AcqRel);
// Notify the accept on switched to available.
if !old && val {
self.waker.wake(WakerInterest::WorkerAvailable(self.idx));
}
}
}
/// Service worker.
///
/// Worker accepts Socket objects via unbounded channel and starts stream processing.
@ -138,9 +200,8 @@ pub(crate) struct ServerWorker {
// It must be dropped as soon as ServerWorker dropping.
rx: UnboundedReceiver<Conn>,
rx2: UnboundedReceiver<Stop>,
counter: WorkerCounter,
services: Box<[WorkerService]>,
availability: WorkerAvailability,
conns: Counter,
factories: Box<[Box<dyn InternalServiceFactory>]>,
state: WorkerState,
shutdown_timeout: Duration,
@ -207,15 +268,15 @@ impl ServerWorker {
pub(crate) fn start(
idx: usize,
factories: Vec<Box<dyn InternalServiceFactory>>,
availability: WorkerAvailability,
waker_queue: WakerQueue,
config: ServerWorkerConfig,
) -> (WorkerHandleAccept, WorkerHandleServer) {
assert!(!availability.available());
let (tx1, rx) = unbounded_channel();
let (tx2, rx2) = unbounded_channel();
let avail = availability.clone();
let counter = Counter::new(config.max_concurrent_connections);
let counter_clone = counter.clone();
// every worker runs in it's own arbiter.
// use a custom tokio runtime builder to change the settings of runtime.
Arbiter::with_tokio_rt(move || {
@ -245,7 +306,7 @@ impl ServerWorker {
Ok(res) => res
.into_iter()
.fold(Vec::new(), |mut services, (factory, token, service)| {
assert_eq!(token.0, services.len());
assert_eq!(token, services.len());
services.push(WorkerService {
factory,
service,
@ -266,8 +327,7 @@ impl ServerWorker {
rx,
rx2,
services,
availability,
conns: Counter::new(config.max_concurrent_connections),
counter: WorkerCounter::new(idx, waker_queue, counter_clone),
factories: factories.into_boxed_slice(),
state: Default::default(),
shutdown_timeout: config.shutdown_timeout,
@ -275,16 +335,16 @@ impl ServerWorker {
});
});
handle_pair(idx, tx1, tx2, avail)
handle_pair(idx, tx1, tx2, counter)
}
fn restart_service(&mut self, token: Token, factory_id: usize) {
fn restart_service(&mut self, idx: usize, factory_id: usize) {
let factory = &self.factories[factory_id];
trace!("Service {:?} failed, restarting", factory.name(token));
self.services[token.0].status = WorkerServiceStatus::Restarting;
trace!("Service {:?} failed, restarting", factory.name(idx));
self.services[idx].status = WorkerServiceStatus::Restarting;
self.state = WorkerState::Restarting(Restart {
factory_id,
token,
token: idx,
fut: factory.create(),
});
}
@ -302,8 +362,8 @@ impl ServerWorker {
});
}
fn check_readiness(&mut self, cx: &mut Context<'_>) -> Result<bool, (Token, usize)> {
let mut ready = self.conns.available(cx);
fn check_readiness(&mut self, cx: &mut Context<'_>) -> Result<bool, (usize, usize)> {
let mut ready = true;
for (idx, srv) in self.services.iter_mut().enumerate() {
if srv.status == WorkerServiceStatus::Available
|| srv.status == WorkerServiceStatus::Unavailable
@ -313,7 +373,7 @@ impl ServerWorker {
if srv.status == WorkerServiceStatus::Unavailable {
trace!(
"Service {:?} is available",
self.factories[srv.factory].name(Token(idx))
self.factories[srv.factory].name(idx)
);
srv.status = WorkerServiceStatus::Available;
}
@ -324,7 +384,7 @@ impl ServerWorker {
if srv.status == WorkerServiceStatus::Available {
trace!(
"Service {:?} is unavailable",
self.factories[srv.factory].name(Token(idx))
self.factories[srv.factory].name(idx)
);
srv.status = WorkerServiceStatus::Unavailable;
}
@ -332,10 +392,10 @@ impl ServerWorker {
Poll::Ready(Err(_)) => {
error!(
"Service {:?} readiness check returned error, restarting",
self.factories[srv.factory].name(Token(idx))
self.factories[srv.factory].name(idx)
);
srv.status = WorkerServiceStatus::Failed;
return Err((Token(idx), srv.factory));
return Err((idx, srv.factory));
}
}
}
@ -354,8 +414,8 @@ enum WorkerState {
struct Restart {
factory_id: usize,
token: Token,
fut: LocalBoxFuture<'static, Result<(Token, BoxedServerService), ()>>,
token: usize,
fut: LocalBoxFuture<'static, Result<(usize, BoxedServerService), ()>>,
}
// Shutdown keep states necessary for server shutdown:
@ -376,10 +436,6 @@ impl Default for WorkerState {
impl Drop for ServerWorker {
fn drop(&mut self) {
// Set availability to true so if accept try to send connection to this worker
// it would find worker is gone and remove it.
// This is helpful when worker is dropped unexpected.
self.availability.set(true);
// Stop the Arbiter ServerWorker runs on on drop.
Arbiter::current().stop();
}
@ -394,8 +450,7 @@ impl Future for ServerWorker {
// `StopWorker` message handler
if let Poll::Ready(Some(Stop { graceful, tx })) = Pin::new(&mut this.rx2).poll_recv(cx)
{
this.availability.set(false);
let num = this.conns.total();
let num = this.counter.total();
if num == 0 {
info!("Shutting down worker, 0 connections");
let _ = tx.send(true);
@ -422,7 +477,6 @@ impl Future for ServerWorker {
WorkerState::Unavailable => match this.check_readiness(cx) {
Ok(true) => {
this.state = WorkerState::Available;
this.availability.set(true);
self.poll(cx)
}
Ok(false) => Poll::Pending,
@ -450,7 +504,7 @@ impl Future for ServerWorker {
this.factories[factory_id].name(token)
);
this.services[token.0].created(service);
this.services[token].created(service);
this.state = WorkerState::Unavailable;
self.poll(cx)
@ -459,7 +513,7 @@ impl Future for ServerWorker {
// Wait for 1 second.
ready!(shutdown.timer.as_mut().poll(cx));
if this.conns.total() == 0 {
if this.counter.total() == 0 {
// Graceful shutdown.
if let WorkerState::Shutdown(shutdown) = mem::take(&mut this.state) {
let _ = shutdown.tx.send(true);
@ -484,22 +538,20 @@ impl Future for ServerWorker {
Ok(true) => {}
Ok(false) => {
trace!("Worker is unavailable");
this.availability.set(false);
this.state = WorkerState::Unavailable;
return self.poll(cx);
}
Err((token, idx)) => {
this.restart_service(token, idx);
this.availability.set(false);
return self.poll(cx);
}
}
// handle incoming io stream
match ready!(Pin::new(&mut this.rx).poll_recv(cx)) {
// handle incoming io stream
Some(msg) => {
let guard = this.conns.get();
let _ = this.services[msg.token.0].service.call((guard, msg.io));
let guard = this.counter.guard();
let _ = this.services[msg.token].service.call((guard, msg.io));
}
None => return Poll::Ready(()),
};