(wait_reading_process_output) [HAVE_PTYS]:

When EIO happens, clear channel from descriptor masks before raising
SIGCHLD signal to avoid busy loop between read and sigchld_handler.
(sigchld_handler): Remove sleep (2007-03-11 & 2007-03-26 changes).

1 files changed, 11 insertions, 10 deletions

diff --git a/src/process.c b/src/process.c
index 14535eb6e1e..f012b2c058d 100644
--- a/src/process.c
+++ b/src/process.c
@@ -4817,8 +4817,8 @@ wait_reading_process_output (time_limit, microsecs, read_kbd, do_display,
                  subprocess termination and SIGCHLD.  */
               else if (nread == 0 && !NETCONN_P (proc))
                 ;
-#endif                          /* O_NDELAY */
-#endif                          /* O_NONBLOCK */
+#endif /* O_NDELAY */
+#endif /* O_NONBLOCK */
 #ifdef HAVE_PTYS
               /* On some OSs with ptys, when the process on one end of
                  a pty exits, the other end gets an error reading with
@@ -4829,11 +4829,17 @@ wait_reading_process_output (time_limit, microsecs, read_kbd, do_display,
                  get a SIGCHLD).
 
                  However, it has been known to happen that the SIGCHLD
-                 got lost.  So raise the signl again just in case.
+                 got lost.  So raise the signal again just in case.
                  It can't hurt.  */
               else if (nread == -1 && errno == EIO)
-                kill (getpid (), SIGCHLD);
-#endif                          /* HAVE_PTYS */
+                {
+                  /* Clear the descriptor now, so we only raise the signal once.  */
+                  FD_CLR (channel, &input_wait_mask);
+                  FD_CLR (channel, &non_keyboard_wait_mask);
+
+                  kill (getpid (), SIGCHLD);
+                }
+#endif /* HAVE_PTYS */
               /* If we can detect process termination, don't consider the process
                  gone just because its pipe is closed.  */
 #ifdef SIGCHLD
@@ -6514,11 +6520,6 @@ sigchld_handler (signo)
       /* Keep trying to get a status until we get a definitive result.  */
       do
         {
-          /* For some reason, this sleep() prevents Emacs from sending
-             loadavg to 5-8(!) for ~10 seconds.
-             See http://thread.gmane.org/gmane.emacs.devel/67722 or
-             http://www.google.com/search?q=busyloop+in+sigchld_handler */
-          usleep (1000);
           errno = 0;
           pid = wait3 (&w, WNOHANG | WUNTRACED, 0);
         }