From cdfb1e88228c10c28f8bfe0f4b0ff1b3b06d1ed4 Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@redhat.com>
Date: Tue, 2 Feb 2010 21:24:52 +0100
Subject: [PATCH] chrt: add --reset-on-fork

This new option allows to set SCHED_RESET_ON_FORK flag for FIFO and RR
policies.

Example:

	$ chrt --fifo --reset-on-fork 1 /bin/bash

	$ schedutils/chrt --pid $$
	pid 31579's current scheduling policy: SCHED_FIFO|SCHED_RESET_ON_FORK
	pid 31579's current scheduling priority: 1

Signed-off-by: Karel Zak <kzak@redhat.com>
---
 schedutils/chrt.1 | 14 ++++++++++++++
 schedutils/chrt.c | 18 ++++++++++++++++--
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/schedutils/chrt.1 b/schedutils/chrt.1
index 06c58b47..9016cfef 100644
--- a/schedutils/chrt.1
+++ b/schedutils/chrt.1
@@ -55,6 +55,11 @@ The
 policy is supported since Linux 2.6.16. The
 .BR SCHED_IDLE
 policy is supported since Linux 2.6.23.
+.PP
+The
+.BR SCHED_RESET_ON_FORK
+flag for policies SCHED_RR and SCHED_FIFO is supported
+since Linux 2.6.31.
 .SH OPTIONS
 .TP
 .B -p, --pid
@@ -69,6 +74,15 @@ set scheduling policy to
 set scheduling policy to
 .BR SCHED_FIFO
 .TP
+.B -R, --reset-on-fork
+add
+.B SCHED_RESET_ON_FORK
+flag to the
+.B SCHED_FIFO
+or
+.B SCHED_RR
+scheduling policy (Linux specific)
+.TP
 .B -i, --idle
 set schedulng policy to
 .BR SCHED_IDLE
diff --git a/schedutils/chrt.c b/schedutils/chrt.c
index 6629c2e8..0ff9b9bb 100644
--- a/schedutils/chrt.c
+++ b/schedutils/chrt.c
@@ -66,6 +66,8 @@ static void show_usage(int rc)
 	"  -i | --idle          set policy to SCHED_IDLE\n"
 	"  -o | --other         set policy to SCHED_OTHER\n"
 	"  -r | --rr            set policy to SCHED_RR (default)\n"
+	"\nScheduling flags:\n"
+	"  -R | --reset-on-fork set SCHED_RESET_ON_FORK for FIFO or RR\n"
 	"\nOptions:\n"
 	"  -h | --help          display this help\n"
 	"  -p | --pid           operate on existing given pid\n"
@@ -161,7 +163,7 @@ static void show_min_max(void)
 
 int main(int argc, char *argv[])
 {
-	int i, policy = SCHED_RR, priority = 0, verbose = 0;
+	int i, policy = SCHED_RR, priority = 0, verbose = 0, policy_flag = 0;
 	struct sched_param sp;
 	pid_t pid = -1;
 
@@ -174,6 +176,7 @@ int main(int argc, char *argv[])
 		{ "max",        0, NULL, 'm' },
 		{ "other",	0, NULL, 'o' },
 		{ "rr",		0, NULL, 'r' },
+		{ "reset-on-fork", 0, NULL, 'R' },
 		{ "verbose",	0, NULL, 'v' },
 		{ "version",	0, NULL, 'V' },
 		{ NULL,		0, NULL, 0 }
@@ -183,7 +186,7 @@ int main(int argc, char *argv[])
 	bindtextdomain(PACKAGE, LOCALEDIR);
 	textdomain(PACKAGE);
 
-	while((i = getopt_long(argc, argv, "+bfiphmorvV", longopts, NULL)) != -1)
+	while((i = getopt_long(argc, argv, "+bfiphmoRrvV", longopts, NULL)) != -1)
 	{
 		int ret = EXIT_FAILURE;
 
@@ -196,6 +199,9 @@ int main(int argc, char *argv[])
 		case 'f':
 			policy = SCHED_FIFO;
 			break;
+		case 'R':
+			policy_flag |= SCHED_RESET_ON_FORK;
+			break;
 		case 'i':
 #ifdef SCHED_IDLE
 			policy = SCHED_IDLE;
@@ -243,6 +249,14 @@ int main(int argc, char *argv[])
 	if (errno)
 		err(EXIT_FAILURE, _("failed to parse priority"));
 
+	/* sanity check */
+	if ((policy_flag & SCHED_RESET_ON_FORK) &&
+	    !(policy == SCHED_FIFO || policy == SCHED_RR))
+		errx(EXIT_FAILURE, _("SCHED_RESET_ON_FORK flag is suppoted for "
+				"SCHED_FIFO and SCHED_RR policies only"));
+
+	policy |= policy_flag;
+
 	if (pid == -1)
 		pid = 0;
 	sp.sched_priority = priority;
-- 
2.39.5