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fix bugs in poll and epoll #1135

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678829e
fix bugs in poll and epoll
Godones Apr 22, 2025
3182bdc
fix: wakeup all epitems instead of the first
Godones Apr 22, 2025
0d15183
Fix wakeup_epoll error
Godones Apr 23, 2025
a3a0c4f
Make test_epoll pass
Godones Apr 23, 2025
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11 changes: 4 additions & 7 deletions kernel/src/driver/tty/tty_port.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@ use system_error::SystemError;

use crate::{
libs::spinlock::{SpinLock, SpinLockGuard},
net::event_poll::EventPoll,
net::event_poll::{EPollEventType, EventPoll},
};

use super::tty_core::TtyCore;
Expand Down Expand Up @@ -80,17 +80,14 @@ pub trait TtyPort: Sync + Send + Debug {
/// 作为客户端的tty ports接收数据
fn receive_buf(&self, buf: &[u8], _flags: &[u8], count: usize) -> Result<usize, SystemError> {
let tty = self.port_data().internal_tty().unwrap();

let ld = tty.ldisc();

let ret = ld.receive_buf2(tty.clone(), buf, None, count);

if let Err(SystemError::ENOSYS) = ret {
return ld.receive_buf(tty, buf, None, count);
}

EventPoll::wakeup_epoll(tty.core().eptiems(), None)?;

let event: usize = ld.poll(tty.clone())?;
let pollflag = EPollEventType::from_bits_truncate(event as u32);
EventPoll::wakeup_epoll(tty.core().eptiems(), pollflag)?;
ret
}
}
Expand Down
4 changes: 2 additions & 2 deletions kernel/src/filesystem/eventfd.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -186,7 +186,7 @@ impl IndexNode for EventFdInode {
drop(eventfd);

// 唤醒epoll中等待的进程
EventPoll::wakeup_epoll(&self.epitems, Some(pollflag))?;
EventPoll::wakeup_epoll(&self.epitems, pollflag)?;

return Ok(8);
}
Expand Down Expand Up @@ -240,7 +240,7 @@ impl IndexNode for EventFdInode {
drop(eventfd);

// 唤醒epoll中等待的进程
EventPoll::wakeup_epoll(&self.epitems, Some(pollflag))?;
EventPoll::wakeup_epoll(&self.epitems, pollflag)?;
return Ok(8);
}

Expand Down
12 changes: 5 additions & 7 deletions kernel/src/filesystem/poll.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -64,9 +64,11 @@ impl<'a> PollAdapter<'a> {
fn poll_all_fds(&mut self, timeout: Option<Instant>) -> Result<usize, SystemError> {
let mut epoll_events = vec![EPollEvent::default(); self.poll_fds.len()];
let len = epoll_events.len() as i32;
let remain_timeout = timeout
.and_then(|t| t.duration_since(Instant::now()))
.map(|t| t.into());
let remain_timeout = timeout.map(|t| {
t.duration_since(Instant::now())
.unwrap_or(Duration::ZERO)
.into()
});
let events = EventPoll::epoll_wait_with_file(
self.ep_file.clone(),
&mut epoll_events,
Expand Down Expand Up @@ -176,10 +178,6 @@ fn do_sys_poll(poll_fds: &mut [PollFd], timeout: Option<Instant>) -> Result<usiz

/// 计算超时的时刻
fn poll_select_set_timeout(timeout_ms: u64) -> Option<Instant> {
if timeout_ms == 0 {
return None;
}

Some(Instant::now() + Duration::from_millis(timeout_ms))
}

Expand Down
8 changes: 5 additions & 3 deletions kernel/src/init/init.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -93,10 +93,12 @@ fn do_start_kernel() {
crate::bpf::init_bpf_system();
crate::debug::jump_label::static_keys_init();

// #[cfg(all(target_arch = "x86_64", feature = "kvm"))]
// crate::virt::kvm::kvm_init();
#[cfg(all(target_arch = "x86_64", feature = "kvm"))]
crate::arch::vm::vmx::vmx_init().unwrap();
{
if let Err(e) = crate::arch::vm::vmx::vmx_init() {
log::error!("KVM init failed: {:?}", e);
}
}
}

/// 在内存管理初始化之前，执行的初始化
Expand Down
4 changes: 2 additions & 2 deletions kernel/src/ipc/pipe.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -287,7 +287,7 @@ impl IndexNode for LockedPipeInode {
let pollflag = EPollEventType::from_bits_truncate(inner_guard.poll(&data)? as u32);
drop(inner_guard);
// 唤醒epoll中等待的进程
EventPoll::wakeup_epoll(&self.epitems, Some(pollflag))?;
EventPoll::wakeup_epoll(&self.epitems, pollflag)?;

//返回读取的字节数
return Ok(num);
Expand Down Expand Up @@ -476,7 +476,7 @@ impl IndexNode for LockedPipeInode {

drop(inner_guard);
// 唤醒epoll中等待的进程
EventPoll::wakeup_epoll(&self.epitems, Some(pollflag))?;
EventPoll::wakeup_epoll(&self.epitems, pollflag)?;

// 返回写入的字节数
return Ok(len);
Expand Down
71 changes: 28 additions & 43 deletions kernel/src/net/event_poll/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -479,7 +479,7 @@ impl EventPoll {
}
} else if timespec.is_none() {
// 非阻塞情况
timeout = true;
timeout = false;
}
// 判断epoll上有没有就绪事件
let mut available = epoll_guard.ep_events_available();
Expand Down Expand Up @@ -775,52 +775,37 @@ impl EventPoll {
/// ### epoll的回调，支持epoll的文件有事件到来时直接调用该方法即可
pub fn wakeup_epoll(
epitems: &SpinLock<LinkedList<Arc<EPollItem>>>,
pollflags: Option<EPollEventType>,
pollflags: EPollEventType,
) -> Result<(), SystemError> {
let mut epitems_guard = epitems.try_lock_irqsave()?;
// 一次只取一个，因为一次也只有一个进程能拿到对应文件的🔓
if let Some(epitem) = epitems_guard.pop_front() {
let pollflags = match pollflags {
Some(flags) => flags,
None => {
if let Some(file) = epitem.file.upgrade() {
// warning: deadlock will happen if poll() is called when pollflags is None
EPollEventType::from_bits_truncate(file.poll()? as u32)
} else {
EPollEventType::empty()
}
}
};
let epitems_guard = epitems.try_lock_irqsave()?;
for epitem in epitems_guard.iter() {
// The upgrade is safe because EventPoll always exists when the epitem is in the list
let epoll = epitem.epoll().upgrade().unwrap();
let mut epoll_guard = epoll.try_lock()?;
let binding = epitem.clone();
let event_guard = binding.event().read();
let ep_events = EPollEventType::from_bits_truncate(event_guard.events());
// 检查事件合理性以及是否有感兴趣的事件
if !(ep_events
.difference(EPollEventType::EP_PRIVATE_BITS)
.is_empty()
|| pollflags.difference(ep_events).is_empty())
{
// TODO: 未处理pm相关

if let Some(epoll) = epitem.epoll().upgrade() {
let mut epoll_guard = epoll.try_lock()?;
let binding = epitem.clone();
let event_guard = binding.event().read();
let ep_events = EPollEventType::from_bits_truncate(event_guard.events());
// 检查事件合理性以及是否有感兴趣的事件
if !(ep_events
.difference(EPollEventType::EP_PRIVATE_BITS)
.is_empty()
|| pollflags.difference(ep_events).is_empty())
{
// TODO: 未处理pm相关

// 首先将就绪的epitem加入等待队列
epoll_guard.ep_add_ready(epitem.clone());

if epoll_guard.ep_has_waiter() {
if ep_events.contains(EPollEventType::EPOLLEXCLUSIVE)
&& !pollflags.contains(EPollEventType::POLLFREE)
{
// 避免惊群
epoll_guard.ep_wake_one();
} else {
epoll_guard.ep_wake_all();
}
// 首先将就绪的epitem加入等待队列
epoll_guard.ep_add_ready(epitem.clone());

if epoll_guard.ep_has_waiter() {
if ep_events.contains(EPollEventType::EPOLLEXCLUSIVE)
&& !pollflags.contains(EPollEventType::POLLFREE)
{
// 避免惊群
epoll_guard.ep_wake_one();
} else {
epoll_guard.ep_wake_all();
}
}

epitems_guard.push_back(epitem);
}
}
Ok(())
Expand Down
2 changes: 1 addition & 1 deletion kernel/src/net/net_core.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -245,7 +245,7 @@ fn send_event(sockets: &smoltcp::iface::SocketSet) -> Result<(), SystemError> {
}
EventPoll::wakeup_epoll(
&posix_item.epitems,
Some(EPollEventType::from_bits_truncate(events as u32)),
EPollEventType::from_bits_truncate(events as u32),
)?;
drop(handle_guard);
// crate::debug!(
Expand Down
2 changes: 1 addition & 1 deletion kernel/src/perf/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -77,7 +77,7 @@ impl PerfEventInode {
fn epoll_callback(&self) -> Result<()> {
let pollflag = EPollEventType::from_bits_truncate(self.do_poll()? as u32);
// 唤醒epoll中等待的进程
EventPoll::wakeup_epoll(&self.epitems, Some(pollflag))
EventPoll::wakeup_epoll(&self.epitems, pollflag)
}
}

Expand Down
31 changes: 19 additions & 12 deletions user/apps/test_epoll/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -98,19 +98,26 @@ int main() {
printf("主线程：epoll_wait 返回，事件数量 = %d\n", nfds);
}

if (nfds != 2) {
printf("主线程：事件数量不匹配，预期 2，实际 %d\n", nfds);
exit(EXIT_FAILURE);
}

// 由于dup复制了 eventfd 描述符，所以 只需要处理一个就行
nfds -= 1;
// 处理就绪事件
// for (int i = 0; i < nfds; i++) {
// if (events[i].data.fd == efd || events[i].data.fd == efd2) {
// uint64_t count;
// int fd = events[i].data.fd;
// printf("主线程：事件发生在 fd = %d\n", fd);
// if (read(fd, &count, sizeof(count)) != sizeof(count)) {
// perror("从 eventfd 读取失败");
// exit(EXIT_FAILURE);
// }
// printf("主线程：接收到 eventfd 事件，计数值 = %lu\n", count);
// }
// }
for (int i = 0; i < nfds; i++) {
if (events[i].data.fd == efd || events[i].data.fd == efd2) {
uint64_t count;
int fd = events[i].data.fd;
printf("主线程：事件发生在 fd = %d\n", fd);
if (read(fd, &count, sizeof(count)) != sizeof(count)) {
perror("从 eventfd 读取失败");
exit(EXIT_FAILURE);
}
printf("主线程：接收到 eventfd 事件，计数值 = %lu\n", count);
}
}

// 等待工作线程结束
pthread_join(tid, NULL);
Expand Down