Change how we report EAGAINs during UFFD serving

packages/orchestrator/internal/sandbox/uffd/serve.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"syscall"
+	"time"
 	"unsafe"
 
 	"go.uber.org/zap"
@@ -54,6 +55,7 @@ outerLoop:
 			}
 
 			if err == unix.EAGAIN {
+				time.Sleep(time.Millisecond)
 				logger.Debug("uffd: eagain during polling, going back to polling")
 
 				continue
@@ -95,7 +97,7 @@ outerLoop:
 		buf := make([]byte, unsafe.Sizeof(userfaultfd.UffdMsg{}))
 
 		for {
-			n, err := syscall.Read(uffd, buf)
+			_, err := syscall.Read(uffd, buf)
 			if err == syscall.EINTR {
 				logger.Debug("uffd: interrupted read, reading again")
 
@@ -108,9 +110,8 @@ outerLoop:
 			}
 
 			if err == syscall.EAGAIN {
-				logger.Debug("uffd: eagain error, going back to polling", zap.Error(err), zap.Int("read_bytes", n))
-
 				// Continue polling the fd.
+				time.Sleep(time.Millisecond)
 				continue outerLoop
 			}