Yield execution in forked children back to PID 1

- Speeds up start-up a bit
 - Ensures the child is moved to its cgroup as soon as possible

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

src/exec.c

@@ -389,6 +389,8 @@ pid_t run_getty(char *tty, char *baud, char *term, int noclear, int nowait, stru
 		speed_t speed;
 		int rc = 1;
 
+		sched_yield();
+
 		speed = stty_parse_speed(baud);
 		prepare_tty(tty, speed, "tty", rlimit);
 		if (activate_console(noclear, nowait)) {
@@ -412,6 +414,8 @@ pid_t run_getty2(char *tty, char *cmd, char *args[], int noclear, int nowait, st
 	if (!pid) {
 		int rc = 1;
 
+		sched_yield();
+
 		/* Dunno speed, tell stty() to not mess with it */
 		prepare_tty(tty, B0, "getty", rlimit);
 		if (activate_console(noclear, nowait)) {

src/helpers.h

@@ -26,6 +26,7 @@
 #define FINIT_HELPERS_H_
 
 #include <mntent.h>
+#include <sched.h>		/* sched_yield() */
 #include <stdarg.h>
 #include <sys/resource.h>
 #include <sys/types.h>

src/service.c

@@ -25,7 +25,6 @@
 #include "config.h"		/* Generated by configure script */
 
 #include <ctype.h>		/* isblank() */
-#include <sched.h>		/* sched_yield() */
 #include <string.h>
 #include <sys/prctl.h>
 #include <sys/resource.h>
@@ -196,6 +195,8 @@ static int lredirect(svc_t *svc)
 		char *tag  = basename(svc->cmd);
 		char *prio = "daemon.info";
 
+		sched_yield();
+
 		fds = open(ptsname(fd), O_RDONLY);
 		close(fd);
 		if (fds == -1)
@@ -445,6 +446,8 @@ static int service_start(svc_t *svc)
 #endif
 		char *args[MAX_NUM_SVC_ARGS + 1];
 
+		sched_yield();
+
 		/* Set configured limits */
 		for (int i = 0; i < RLIMIT_NLIMITS; i++) {
 			if (setrlimit(i, &svc->rlimit[i]) == -1)