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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-12-05 23:45:34 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-12-11 12:08:44 +0100
commit61cb5758d3c46bc1ba87694fefc0d9653613ce6b (patch)
tree122cbd1c3de0c1c3bf4591fb975e4de6d4de3ca0 /drivers
parent800fb34a99ce7d22dca839c90f869c7a12b50f70 (diff)
downloadlinux-61cb5758d3c46bc1ba87694fefc0d9653613ce6b.tar.gz
cpuidle: Add cpuidle.governor= command line parameter
Add cpuidle.governor= command line parameter to allow the default
cpuidle governor to be replaced.

That is useful, for example, if someone running a tickful kernel
wants to use the menu governor on it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/cpuidle/cpuidle.c1
-rw-r--r--drivers/cpuidle/cpuidle.h1
-rw-r--r--drivers/cpuidle/governor.c9
3 files changed, 9 insertions, 2 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 4a97446f66d8..f7c58043e50f 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -702,4 +702,5 @@ static int __init cpuidle_init(void)
 }
 
 module_param(off, int, 0444);
+module_param_string(governor, param_governor, CPUIDLE_NAME_LEN, 0444);
 core_initcall(cpuidle_init);
diff --git a/drivers/cpuidle/cpuidle.h b/drivers/cpuidle/cpuidle.h
index 2965ab32a583..d6613101af92 100644
--- a/drivers/cpuidle/cpuidle.h
+++ b/drivers/cpuidle/cpuidle.h
@@ -7,6 +7,7 @@
 #define __DRIVER_CPUIDLE_H
 
 /* For internal use only */
+extern char param_governor[];
 extern struct cpuidle_governor *cpuidle_curr_governor;
 extern struct list_head cpuidle_governors;
 extern struct list_head cpuidle_detected_devices;
diff --git a/drivers/cpuidle/governor.c b/drivers/cpuidle/governor.c
index 9fed1b829292..bb93e5cf6a4a 100644
--- a/drivers/cpuidle/governor.c
+++ b/drivers/cpuidle/governor.c
@@ -11,10 +11,13 @@
 #include <linux/cpu.h>
 #include <linux/cpuidle.h>
 #include <linux/mutex.h>
+#include <linux/module.h>
 #include <linux/pm_qos.h>
 
 #include "cpuidle.h"
 
+char param_governor[CPUIDLE_NAME_LEN];
+
 LIST_HEAD(cpuidle_governors);
 struct cpuidle_governor *cpuidle_curr_governor;
 
@@ -86,9 +89,11 @@ int cpuidle_register_governor(struct cpuidle_governor *gov)
 	mutex_lock(&cpuidle_lock);
 	if (__cpuidle_find_governor(gov->name) == NULL) {
 		ret = 0;
-		list_add_tail(&gov->governor_list, &cpuidle_governors);
 		if (!cpuidle_curr_governor ||
-		    cpuidle_curr_governor->rating < gov->rating)
+		    !strncasecmp(param_governor, gov->name, CPUIDLE_NAME_LEN) ||
+		    (cpuidle_curr_governor->rating < gov->rating &&
+		     strncasecmp(param_governor, cpuidle_curr_governor->name,
+				 CPUIDLE_NAME_LEN)))
 			cpuidle_switch_governor(gov);
 	}
 	mutex_unlock(&cpuidle_lock);