sched: add CFS debug sysctls

add CFS debug sysctls: only tweakable if SCHED_DEBUG is enabled.
This allows for faster debugging of scheduler problems.
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/sysctl.c

@@ -206,7 +206,87 @@ static ctl_table root_table[] = {
 	{ .ctl_name = 0 }
 };
 
+#ifdef CONFIG_SCHED_DEBUG
+static unsigned long min_sched_granularity_ns = 100000;		/* 100 usecs */
+static unsigned long max_sched_granularity_ns = 1000000000;	/* 1 second */
+static unsigned long min_wakeup_granularity_ns;			/* 0 usecs */
+static unsigned long max_wakeup_granularity_ns = 1000000000;	/* 1 second */
+#endif
+
 static ctl_table kern_table[] = {
+#ifdef CONFIG_SCHED_DEBUG
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname	= "sched_granularity_ns",
+		.data		= &sysctl_sched_granularity,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_minmax,
+		.strategy	= &sysctl_intvec,
+		.extra1		= &min_sched_granularity_ns,
+		.extra2		= &max_sched_granularity_ns,
+	},
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname	= "sched_wakeup_granularity_ns",
+		.data		= &sysctl_sched_wakeup_granularity,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_minmax,
+		.strategy	= &sysctl_intvec,
+		.extra1		= &min_wakeup_granularity_ns,
+		.extra2		= &max_wakeup_granularity_ns,
+	},
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname	= "sched_batch_wakeup_granularity_ns",
+		.data		= &sysctl_sched_batch_wakeup_granularity,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_minmax,
+		.strategy	= &sysctl_intvec,
+		.extra1		= &min_wakeup_granularity_ns,
+		.extra2		= &max_wakeup_granularity_ns,
+	},
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname	= "sched_stat_granularity_ns",
+		.data		= &sysctl_sched_stat_granularity,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_minmax,
+		.strategy	= &sysctl_intvec,
+		.extra1		= &min_wakeup_granularity_ns,
+		.extra2		= &max_wakeup_granularity_ns,
+	},
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname	= "sched_runtime_limit_ns",
+		.data		= &sysctl_sched_runtime_limit,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_minmax,
+		.strategy	= &sysctl_intvec,
+		.extra1		= &min_sched_granularity_ns,
+		.extra2		= &max_sched_granularity_ns,
+	},
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname	= "sched_child_runs_first",
+		.data		= &sysctl_sched_child_runs_first,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec,
+	},
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname	= "sched_features",
+		.data		= &sysctl_sched_features,
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec,
+	},
+#endif
 	{
 		.ctl_name	= KERN_PANIC,
 		.procname	= "panic",