Optimize the events handling for epoll

panjf2000 · Apr 17, 2024 · e299975 · e299975
1 parent f934133
commit e299975
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Showing 5 changed files with 16 additions and 26 deletions.
diff --git a/connection_linux.go b/connection_linux.go
@@ -17,20 +17,16 @@
 
 package gnet
 
-import "github.com/panjf2000/gnet/v2/internal/netpoll"
+import (
+	"golang.org/x/sys/unix"
 
-func (c *conn) handleEvents(_ int, ev uint32) error {
-	// Don't change the ordering of processing EPOLLOUT | EPOLLRDHUP / EPOLLIN unless you're 100%
-	// sure what you're doing!
-	// Re-ordering can easily introduce bugs and bad side-effects, as I found out painfully in the past.
+	"github.com/panjf2000/gnet/v2/internal/netpoll"
+)
 
-	// We should always check for the EPOLLOUT event first, as we must try to send the leftover data back to
-	// the peer when any error occurs on a connection.
-	//
-	// Either an EPOLLOUT or EPOLLERR event may be fired when a connection is refused.
-	// In either case write() should take care of it properly:
-	// 1) writing data back,
-	// 2) closing the connection.
+func (c *conn) handleEvents(_ int, ev uint32) error {
+	if ev&netpoll.ErrEvents != 0 && ev&netpoll.InEvents == 0 && ev&netpoll.OutEvents == 0 {
+		return c.loop.close(c, unix.ECONNRESET)
+	}
 	if ev&netpoll.OutEvents != 0 && !c.outboundBuffer.IsEmpty() {
 		if err := c.loop.write(c); err != nil {
 			return err

diff --git a/internal/netpoll/epoll_default_poller.go b/internal/netpoll/epoll_default_poller.go
@@ -196,7 +196,7 @@ func (p *Poller) Polling(callback PollEventHandler) error {
 }
 
 const (
-	readEvents      = unix.EPOLLPRI | unix.EPOLLIN
+	readEvents      = unix.EPOLLIN | unix.EPOLLPRI | unix.EPOLLRDHUP
 	writeEvents     = unix.EPOLLOUT
 	readWriteEvents = readEvents | writeEvents
 )

diff --git a/internal/netpoll/epoll_events.go b/internal/netpoll/epoll_events.go
@@ -35,7 +35,7 @@ const (
 	// reading/writing from/to a closed socket, etc.
 	ErrEvents = unix.EPOLLERR | unix.EPOLLHUP | unix.EPOLLRDHUP
 	// OutEvents combines EPOLLOUT event and some exceptional events.
-	OutEvents = ErrEvents | unix.EPOLLOUT
+	OutEvents = unix.EPOLLERR | unix.EPOLLHUP | unix.EPOLLOUT
 	// InEvents combines EPOLLIN/EPOLLPRI events and some exceptional events.
 	InEvents = ErrEvents | unix.EPOLLIN | unix.EPOLLPRI
 )

diff --git a/internal/netpoll/epoll_optimized_poller.go b/internal/netpoll/epoll_optimized_poller.go
@@ -198,7 +198,7 @@ func (p *Poller) Polling() error {
 }
 
 const (
-	readEvents      = unix.EPOLLPRI | unix.EPOLLIN
+	readEvents      = unix.EPOLLIN | unix.EPOLLPRI | unix.EPOLLRDHUP
 	writeEvents     = unix.EPOLLOUT
 	readWriteEvents = readEvents | writeEvents
 )

diff --git a/reactor_default_linux.go b/reactor_default_linux.go
@@ -20,6 +20,8 @@ package gnet
 import (
 	"runtime"
 
+	"golang.org/x/sys/unix"
+
 	"github.com/panjf2000/gnet/v2/internal/netpoll"
 	"github.com/panjf2000/gnet/v2/pkg/errors"
 )
@@ -96,17 +98,9 @@ func (el *eventloop) run() error {
 
 	err := el.poller.Polling(func(fd int, ev uint32) error {
 		if c := el.connections.getConn(fd); c != nil {
-			// Don't change the ordering of processing EPOLLOUT | EPOLLRDHUP / EPOLLIN unless you're 100%
-			// sure what you're doing!
-			// Re-ordering can easily introduce bugs and bad side-effects, as I found out painfully in the past.
-
-			// We should always check for the EPOLLOUT event first, as we must try to send the leftover data back to
-			// the peer when any error occurs on a connection.
-			//
-			// Either an EPOLLOUT or EPOLLERR event may be fired when a connection is refused.
-			// In either case write() should take care of it properly:
-			// 1) writing data back,
-			// 2) closing the connection.
+			if ev&netpoll.ErrEvents != 0 && ev&netpoll.InEvents == 0 && ev&netpoll.OutEvents == 0 {
+				return el.close(c, unix.ECONNRESET)
+			}
 			if ev&netpoll.OutEvents != 0 && !c.outboundBuffer.IsEmpty() {
 				if err := el.write(c); err != nil {
 					return err