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From: Marcelo Tosatti <mtosatti@redhat.com>
To: kvm-devel <kvm@vger.kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Radim Krcmar <rkrcmar@redhat.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Wanpeng Li <kernellwp@gmail.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Raslan KarimAllah <karahmed@amazon.de>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Ankur Arora <ankur.a.arora@oracle.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	linux-pm@vger.kernel.org, Marcelo Tosatti <mtosatti@redhat.com>
Subject: [patch 2/5] cpuidle: add get_poll_time callback
Date: Thu, 13 Jun 2019 18:45:34 -0400
Message-ID: <20190613225022.969533311@redhat.com> (raw)
In-Reply-To: <20190613224532.949768676@redhat.com>

Add a "get_poll_time" callback to the cpuidle_governor structure,
and change poll state to poll for that amount of time.

Provide a default method for it, while allowing individual governors
to override it.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

---
 drivers/cpuidle/cpuidle.c    |   40 ++++++++++++++++++++++++++++++++++++++++
 drivers/cpuidle/poll_state.c |   11 ++---------
 include/linux/cpuidle.h      |    8 ++++++++
 3 files changed, 50 insertions(+), 9 deletions(-)

Index: linux-2.6.git/drivers/cpuidle/cpuidle.c
===================================================================
--- linux-2.6.git.orig/drivers/cpuidle/cpuidle.c	2019-06-13 17:57:33.111185824 -0400
+++ linux-2.6.git/drivers/cpuidle/cpuidle.c	2019-06-13 18:09:48.158500660 -0400
@@ -362,6 +362,46 @@
 }
 
 /**
+ * cpuidle_default_poll_time - default routine used to return poll time
+ * governors can override it if necessary
+ *
+ * @drv:   the cpuidle driver tied with the cpu
+ * @dev:   the cpuidle device
+ *
+ */
+static u64 cpuidle_default_poll_time(struct cpuidle_driver *drv,
+				     struct cpuidle_device *dev)
+{
+	int i;
+
+	for (i = 1; i < drv->state_count; i++) {
+		if (drv->states[i].disabled || dev->states_usage[i].disable)
+			continue;
+
+		return (u64)drv->states[i].target_residency * NSEC_PER_USEC;
+	}
+
+	return TICK_NSEC;
+}
+
+/**
+ * cpuidle_get_poll_time - tell the polling driver how much time to poll,
+ *			   in nanoseconds.
+ *
+ * @drv: the cpuidle driver tied with the cpu
+ * @dev: the cpuidle device
+ *
+ */
+u64 cpuidle_get_poll_time(struct cpuidle_driver *drv,
+			  struct cpuidle_device *dev)
+{
+	if (cpuidle_curr_governor->get_poll_time)
+		return cpuidle_curr_governor->get_poll_time(drv, dev);
+
+	return cpuidle_default_poll_time(drv, dev);
+}
+
+/**
  * cpuidle_install_idle_handler - installs the cpuidle idle loop handler
  */
 void cpuidle_install_idle_handler(void)
Index: linux-2.6.git/drivers/cpuidle/poll_state.c
===================================================================
--- linux-2.6.git.orig/drivers/cpuidle/poll_state.c	2019-06-13 17:57:33.111185824 -0400
+++ linux-2.6.git/drivers/cpuidle/poll_state.c	2019-06-13 18:01:19.846944820 -0400
@@ -20,16 +20,9 @@
 	local_irq_enable();
 	if (!current_set_polling_and_test()) {
 		unsigned int loop_count = 0;
-		u64 limit = TICK_NSEC;
-		int i;
+		u64 limit;
 
-		for (i = 1; i < drv->state_count; i++) {
-			if (drv->states[i].disabled || dev->states_usage[i].disable)
-				continue;
-
-			limit = (u64)drv->states[i].target_residency * NSEC_PER_USEC;
-			break;
-		}
+		limit = cpuidle_get_poll_time(drv, dev);
 
 		while (!need_resched()) {
 			cpu_relax();
Index: linux-2.6.git/include/linux/cpuidle.h
===================================================================
--- linux-2.6.git.orig/include/linux/cpuidle.h	2019-06-13 17:57:33.111185824 -0400
+++ linux-2.6.git/include/linux/cpuidle.h	2019-06-13 18:01:19.846944820 -0400
@@ -132,6 +132,8 @@
 extern int cpuidle_enter(struct cpuidle_driver *drv,
 			 struct cpuidle_device *dev, int index);
 extern void cpuidle_reflect(struct cpuidle_device *dev, int index);
+extern u64 cpuidle_get_poll_time(struct cpuidle_driver *drv,
+				 struct cpuidle_device *dev);
 
 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 extern struct cpuidle_driver *cpuidle_get_driver(void);
@@ -166,6 +168,9 @@
 				struct cpuidle_device *dev, int index)
 {return -ENODEV; }
 static inline void cpuidle_reflect(struct cpuidle_device *dev, int index) { }
+extern u64 cpuidle_get_poll_time(struct cpuidle_driver *drv,
+				 struct cpuidle_device *dev)
+{return 0; }
 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 {return -ENODEV; }
 static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
@@ -246,6 +251,9 @@
 					struct cpuidle_device *dev,
 					bool *stop_tick);
 	void (*reflect)		(struct cpuidle_device *dev, int index);
+
+	u64 (*get_poll_time)	(struct cpuidle_driver *drv,
+					struct cpuidle_device *dev);
 };
 
 #ifdef CONFIG_CPU_IDLE



  parent reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-13 22:45 [patch 0/5] cpuidle haltpoll driver and governor (v4) Marcelo Tosatti
2019-06-13 22:45 ` [patch 1/5] drivers/cpuidle: add cpuidle-haltpoll driver Marcelo Tosatti
2019-06-25 21:50   ` Rafael J. Wysocki
2019-06-26  8:40   ` Rafael J. Wysocki
2019-06-13 22:45 ` Marcelo Tosatti [this message]
2019-06-25 21:52   ` [patch 2/5] cpuidle: add get_poll_time callback Rafael J. Wysocki
2019-06-13 22:45 ` [patch 3/5] cpuidle: add haltpoll governor Marcelo Tosatti
2019-06-21  0:34   ` Doug Smythies
2019-06-27 18:08     ` Marcelo Tosatti
2019-06-25 21:57   ` Rafael J. Wysocki
2019-06-13 22:45 ` [patch 4/5] kvm: x86: add host poll control msrs Marcelo Tosatti
2019-06-13 22:45 ` [patch 5/5] cpuidle-haltpoll: disable host side polling when kvm virtualized Marcelo Tosatti
2019-07-01 18:53 [patch 0/5] cpuidle haltpoll driver and governor (v5) Marcelo Tosatti
2019-07-01 18:53 ` [patch 2/5] cpuidle: add get_poll_time callback Marcelo Tosatti
2019-07-03  9:50   ` Rafael J. Wysocki

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