[ Optimization ]: replace pipe() by pipe2()

[pavlinux]

Linux only :-P

• The pipe2() was added to Linux in version 2.6.27. It is a variant of the normal pipe syscall, but takes an extra flags argument which can be the ORed value of O_NONBLOCK and O_CLOEXEC. The original pipe syscall is now defined as like the pipe2 syscall, but with the flags variable set to zero.

• The pipe2() glibc support is available starting with version 2.9.

• The pipe2() is Linux-specific.

lib/utilunix.c

@@ -340 +340 @@
 void
 open_error_pipe (void)
 {
-    if (pipe (error_pipe) < 0)
+    if (pipe2(error_pipe, O_DIRECT) < 0)
     {
         message (D_NORMAL, _("Warning"), _("Pipe failed"));
     }

src/background.c

@@ -514 +514 @@
     int back_comm[2];           /* back connection */
     pid_t pid;
 
-    if (pipe (comm) == -1)
+    if (pipe2(comm, O_DIRECT) == -1)
         return -1;
 
-    if (pipe (back_comm) == -1)
+    if (pipe2(back_comm, O_DIRECT) == -1)
         return -1;
 
     pid = fork ();

src/cons.handler.c

@@ -148 +148 @@
         status = close (pipefd1[1]);
         status = close (pipefd2[0]);
         /* Create two pipes for communication */
-        if (!((pipe (pipefd1) == 0) && ((pipe (pipefd2)) == 0)))
+        if (!((pipe2(pipefd1, O_DIRECT) == 0) && ((pipe2(pipefd2, O_DIRECT)) == 0)))
         {
             mc_global.tty.console_flag = '\0';
             break;

src/subshell.c

@@ -850 +850 @@
                 return;
             }
         }
-        else /* subshell_type is BASH or ZSH */ if (pipe (subshell_pipe))
+        else /* subshell_type is BASH or ZSH */ if (pipe2(subshell_pipe, O_DIRECT))
         {
             perror (__FILE__ ": couldn't create pipe");
             mc_global.tty.use_subshell = FALSE;

src/vfs/fish/fish.c

@@ -312 +312 @@
     int fileset1[2], fileset2[2];
     int res;
 
-    if ((pipe (fileset1) < 0) || (pipe (fileset2) < 0))
+    if ((pipe2(fileset1, O_DIRECT) < 0) || (pipe2(fileset2, O_DIRECT) < 0))
         vfs_die ("Cannot pipe(): %m.");
 
     res = fork ();

[pavlinux]

P.S.

O_DIRECT flag work only from kernel 3.4 and other backports (for ex. 3.2.19+)

[andrew_b]

Could you make your patch not for Linux only?