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authorMarcelo Tosatti <mtosatti@redhat.com>2019-07-03 20:51:25 -0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2019-07-30 17:27:37 +0200
commitfa86ee90eb1111267de67cb4272b5ce711f18cbb (patch)
tree8b1ff641cdd151090eca3cad29e80e3e2c2eefe4 /drivers/cpuidle
parent609488bc979f99f805f34e9a32c1e3b71179d10b (diff)
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: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpuidle')
-rw-r--r--drivers/cpuidle/Kconfig9
-rw-r--r--drivers/cpuidle/Makefile1
-rw-r--r--drivers/cpuidle/cpuidle-haltpoll.c68
3 files changed, 78 insertions, 0 deletions
diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
index a4ac31e4a58c..cc8efc56be7d 100644
--- a/drivers/cpuidle/Kconfig
+++ b/drivers/cpuidle/Kconfig
@@ -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
diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
index 9d7176cee3d3..240227474cd9 100644
--- a/drivers/cpuidle/Makefile
+++ b/drivers/cpuidle/Makefile
@@ -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
diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c
new file mode 100644
index 000000000000..35cfb53e9287
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-haltpoll.c
@@ -0,0 +1,68 @@
+// 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>");