Commit fa86ee90 authored by Marcelo Tosatti's avatar Marcelo Tosatti Committed by Rafael J. Wysocki
Browse files

add cpuidle-haltpoll driver 



Add a cpuidle driver that calls the architecture default_idle routine.

To be used in conjunction with the haltpoll governor.

Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 609488bc

arch/x86/kernel/process.c

+1 −1
Original line number Diff line number Diff line
@@ -580,7 +580,7 @@ void __cpuidle default_idle(void) 
	safe_halt();

	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());

}

#ifdef CONFIG_APM_MODULE

#if defined(CONFIG_APM_MODULE) || defined(CONFIG_HALTPOLL_CPUIDLE_MODULE)

EXPORT_SYMBOL(default_idle);

#endif

drivers/cpuidle/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -51,6 +51,15 @@ depends on PPC 
source "drivers/cpuidle/Kconfig.powerpc"

endmenu



config HALTPOLL_CPUIDLE

       tristate "Halt poll cpuidle driver"

       depends on X86 && KVM_GUEST

       default y

       help

         This option enables halt poll cpuidle driver, which allows to poll

         before halting in the guest (more efficient than polling in the

         host via halt_poll_ns for some scenarios).



endif



config ARCH_NEEDS_CPU_IDLE_COUPLED

drivers/cpuidle/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ obj-y += cpuidle.o driver.o governor.o sysfs.o governors/ 
obj-$(CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED) += coupled.o

obj-$(CONFIG_DT_IDLE_STATES)		  += dt_idle_states.o

obj-$(CONFIG_ARCH_HAS_CPU_RELAX)	  += poll_state.o

obj-$(CONFIG_HALTPOLL_CPUIDLE)		  += cpuidle-haltpoll.o



##################################################################################

# ARM SoC drivers

drivers/cpuidle/cpuidle-haltpoll.c

0 → 100644
+68 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * cpuidle driver for haltpoll governor.

 *

 * Copyright 2019 Red Hat, Inc. and/or its affiliates.

 *

 * This work is licensed under the terms of the GNU GPL, version 2.  See

 * the COPYING file in the top-level directory.

 *

 * Authors: Marcelo Tosatti <mtosatti@redhat.com>

 */



#include <linux/init.h>

#include <linux/cpuidle.h>

#include <linux/module.h>

#include <linux/sched/idle.h>

#include <linux/kvm_para.h>



static int default_enter_idle(struct cpuidle_device *dev,

			      struct cpuidle_driver *drv, int index)

{

	if (current_clr_polling_and_test()) {

		local_irq_enable();

		return index;

	}

	default_idle();

	return index;

}



static struct cpuidle_driver haltpoll_driver = {

	.name = "haltpoll",

	.owner = THIS_MODULE,

	.states = {

		{ /* entry 0 is for polling */ },

		{

			.enter			= default_enter_idle,

			.exit_latency		= 1,

			.target_residency	= 1,

			.power_usage		= -1,

			.name			= "haltpoll idle",

			.desc			= "default architecture idle",

		},

	},

	.safe_state_index = 0,

	.state_count = 2,

};



static int __init haltpoll_init(void)

{

	struct cpuidle_driver *drv = &haltpoll_driver;



	cpuidle_poll_state_init(drv);



	if (!kvm_para_available())

		return 0;



	return cpuidle_register(&haltpoll_driver, NULL);

}



static void __exit haltpoll_exit(void)

{

	cpuidle_unregister(&haltpoll_driver);

}



module_init(haltpoll_init);

module_exit(haltpoll_exit);

MODULE_LICENSE("GPL");

MODULE_AUTHOR("Marcelo Tosatti <mtosatti@redhat.com>");