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

@@ -356,6 +356,10 @@
 	autoconf=	[IPV6]
 			See Documentation/networking/ipv6.rst.
 
+	autogroup=	[KNL] Enable or disable scheduler automatic task group
+			creation.
+			Format: <bool>
+
 	show_lapic=	[APIC,X86] Advanced Programmable Interrupt Controller
 			Limit apic dumping. The parameter defines the maximal
 			number of local apics being dumped. Also it is possible
@@ -3235,8 +3239,6 @@
 	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.
-
 	nobats		[PPC] Do not use BATs for mapping kernel lowmem
 			on "Classic" PPC cores.
 

init/Kconfig

@@ -1238,6 +1238,18 @@ 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

@@ -5,7 +5,8 @@
 #include <linux/nospec.h>
 #include "sched.h"
 
-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;
 
@@ -197,11 +198,12 @@ 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