XANMOD: sched/autogroup: Add kernel parameter and config option to en…

…able/disable autogroup feature by default

Signed-off-by: Alexandre Frade <kernel@xanmod.org>

Documentation/admin-guide/kernel-parameters.txt

@@ -443,6 +443,10 @@
 			Format: <int> (must be >=0)
 			Default: 64
 
+	autogroup=	[KNL] Enable or disable scheduler automatic task group
+			creation.
+			Format: <bool>
+
 	bau=		[X86_UV] Enable the BAU on SGI UV.  The default
 			behavior is to disable the BAU (i.e. bau=0).
 			Format: { "0" | "1" }
@@ -3619,8 +3623,6 @@
 	noapic		[SMP,APIC] Tells the kernel to not make use of any
 			IOAPICs that may be present in the system.
 
-	noautogroup	Disable scheduler automatic task group creation.
-
 	nocache		[ARM]
 
 	nodsp		[SH] Disable hardware DSP at boot time.

init/Kconfig

@@ -1293,6 +1293,18 @@ config SCHED_AUTOGROUP
 	  desktop applications.  Task group autogeneration is currently based
 	  upon task session.
 
+config SCHED_AUTOGROUP_DEFAULT_ENABLED
+	bool "Enable automatic process group scheduling feature"
+	default y
+	depends on SCHED_AUTOGROUP
+	help
+	  If set, automatic process group scheduling will be enabled per
+	  default but can be disabled through passing autogroup=0 on the
+	  kernel commandline during boot or a value of 0 via the file
+	  proc/sys/kernel/sched_autogroup_enabled.
+
+	  If unsure say Y.
+
 config SYSFS_DEPRECATED
 	bool "Enable deprecated sysfs features to support old userspace tools"
 	depends on SYSFS

kernel/sched/autogroup.c

@@ -4,7 +4,8 @@
  * Auto-group scheduling implementation:
  */
 
-unsigned int __read_mostly sysctl_sched_autogroup_enabled = 1;
+unsigned int __read_mostly sysctl_sched_autogroup_enabled =
+		IS_ENABLED(CONFIG_SCHED_AUTOGROUP_DEFAULT_ENABLED) ? 1 : 0;
 static struct autogroup autogroup_default;
 static atomic_t autogroup_seq_nr;
 
@@ -220,11 +221,13 @@ void sched_autogroup_exit(struct signal_struct *sig)
 
 static int __init setup_autogroup(char *str)
 {
-	sysctl_sched_autogroup_enabled = 0;
+	unsigned long enabled;
+	if (!kstrtoul(str, 0, &enabled))
+		sysctl_sched_autogroup_enabled = enabled ? 1 : 0;
 
 	return 1;
 }
-__setup("noautogroup", setup_autogroup);
+__setup("autogroup=", setup_autogroup);
 
 #ifdef CONFIG_PROC_FS