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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux PM <linux-pm@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Amit Kucheria <amit.kucheria@linaro.org>,
	Daniel Lezcano <daniel.lezcano@linaro.org>
Subject: [PATCH 09/28] PM: QoS: Drop PM_QOS_CPU_DMA_LATENCY notifier chain
Date: Wed, 12 Feb 2020 00:02:30 +0100	[thread overview]
Message-ID: <1901998.KeA0Q3sAH1@kreacher> (raw)
In-Reply-To: <1654227.8mz0SueHsU@kreacher>

From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>

Notice that pm_qos_remove_notifier() is not used at all and the only
caller of pm_qos_add_notifier() is the cpuidle core, which only needs
the PM_QOS_CPU_DMA_LATENCY notifier to invoke wake_up_all_idle_cpus()
upon changes of the PM_QOS_CPU_DMA_LATENCY target value.

First, to ensure that wake_up_all_idle_cpus() will be called
whenever the PM_QOS_CPU_DMA_LATENCY target value changes, modify the
pm_qos_add/update/remove_request() family of functions to check if
the effective constraint for the PM_QOS_CPU_DMA_LATENCY has changed
and call wake_up_all_idle_cpus() directly in that case.

Next, drop the PM_QOS_CPU_DMA_LATENCY notifier from cpuidle as it is
not necessary any more.

Finally, drop both pm_qos_add_notifier() and pm_qos_remove_notifier(),
as they have no callers now, along with cpu_dma_lat_notifier which is
only used by them.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/cpuidle/cpuidle.c | 40 +---------------------------------------
 include/linux/pm_qos.h    |  2 --
 kernel/power/qos.c        | 47 +++++++++++------------------------------------
 3 files changed, 12 insertions(+), 77 deletions(-)

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index de81298051b3..c149d9e20dfd 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -736,53 +736,15 @@ int cpuidle_register(struct cpuidle_driver *drv,
 }
 EXPORT_SYMBOL_GPL(cpuidle_register);
 
-#ifdef CONFIG_SMP
-
-/*
- * This function gets called when a part of the kernel has a new latency
- * requirement.  This means we need to get all processors out of their C-state,
- * and then recalculate a new suitable C-state. Just do a cross-cpu IPI; that
- * wakes them all right up.
- */
-static int cpuidle_latency_notify(struct notifier_block *b,
-		unsigned long l, void *v)
-{
-	wake_up_all_idle_cpus();
-	return NOTIFY_OK;
-}
-
-static struct notifier_block cpuidle_latency_notifier = {
-	.notifier_call = cpuidle_latency_notify,
-};
-
-static inline void latency_notifier_init(struct notifier_block *n)
-{
-	pm_qos_add_notifier(PM_QOS_CPU_DMA_LATENCY, n);
-}
-
-#else /* CONFIG_SMP */
-
-#define latency_notifier_init(x) do { } while (0)
-
-#endif /* CONFIG_SMP */
-
 /**
  * cpuidle_init - core initializer
  */
 static int __init cpuidle_init(void)
 {
-	int ret;
-
 	if (cpuidle_disabled())
 		return -ENODEV;
 
-	ret = cpuidle_add_interface(cpu_subsys.dev_root);
-	if (ret)
-		return ret;
-
-	latency_notifier_init(&cpuidle_latency_notifier);
-
-	return 0;
+	return cpuidle_add_interface(cpu_subsys.dev_root);
 }
 
 module_param(off, int, 0444);
diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
index bef110aa80cc..cb57e5918a25 100644
--- a/include/linux/pm_qos.h
+++ b/include/linux/pm_qos.h
@@ -149,8 +149,6 @@ void pm_qos_update_request(struct pm_qos_request *req,
 void pm_qos_remove_request(struct pm_qos_request *req);
 
 int pm_qos_request(int pm_qos_class);
-int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier);
-int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier);
 int pm_qos_request_active(struct pm_qos_request *req);
 s32 pm_qos_read_value(struct pm_qos_constraints *c);
 
diff --git a/kernel/power/qos.c b/kernel/power/qos.c
index 952c5f55e23c..201b43bc6457 100644
--- a/kernel/power/qos.c
+++ b/kernel/power/qos.c
@@ -56,14 +56,12 @@
  */
 static DEFINE_SPINLOCK(pm_qos_lock);
 
-static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
 static struct pm_qos_constraints cpu_dma_constraints = {
 	.list = PLIST_HEAD_INIT(cpu_dma_constraints.list),
 	.target_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
 	.default_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
 	.no_constraint_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
 	.type = PM_QOS_MIN,
-	.notifiers = &cpu_dma_lat_notifier,
 };
 
 /**
@@ -247,6 +245,14 @@ int pm_qos_request_active(struct pm_qos_request *req)
 }
 EXPORT_SYMBOL_GPL(pm_qos_request_active);
 
+static void cpu_latency_qos_update(struct pm_qos_request *req,
+				   enum pm_qos_req_action action, s32 value)
+{
+	int ret = pm_qos_update_target(req->qos, &req->node, action, value);
+	if (ret > 0)
+		wake_up_all_idle_cpus();
+}
+
 /**
  * pm_qos_add_request - inserts new qos request into the list
  * @req: pointer to a preallocated handle
@@ -273,7 +279,7 @@ void pm_qos_add_request(struct pm_qos_request *req,
 	trace_pm_qos_add_request(PM_QOS_CPU_DMA_LATENCY, value);
 
 	req->qos = &cpu_dma_constraints;
-	pm_qos_update_target(req->qos, &req->node, PM_QOS_ADD_REQ, value);
+	cpu_latency_qos_update(req, PM_QOS_ADD_REQ, value);
 }
 EXPORT_SYMBOL_GPL(pm_qos_add_request);
 
@@ -302,7 +308,7 @@ void pm_qos_update_request(struct pm_qos_request *req, s32 new_value)
 	if (new_value == req->node.prio)
 		return;
 
-	pm_qos_update_target(req->qos, &req->node, PM_QOS_UPDATE_REQ, new_value);
+	cpu_latency_qos_update(req, PM_QOS_UPDATE_REQ, new_value);
 }
 EXPORT_SYMBOL_GPL(pm_qos_update_request);
 
@@ -327,42 +333,11 @@ void pm_qos_remove_request(struct pm_qos_request *req)
 
 	trace_pm_qos_remove_request(PM_QOS_CPU_DMA_LATENCY, PM_QOS_DEFAULT_VALUE);
 
-	pm_qos_update_target(req->qos, &req->node, PM_QOS_REMOVE_REQ,
-			     PM_QOS_DEFAULT_VALUE);
+	cpu_latency_qos_update(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
 	memset(req, 0, sizeof(*req));
 }
 EXPORT_SYMBOL_GPL(pm_qos_remove_request);
 
-/**
- * pm_qos_add_notifier - sets notification entry for changes to target value
- * @pm_qos_class: Ignored.
- * @notifier: notifier block managed by caller.
- *
- * will register the notifier into a notification chain that gets called
- * upon changes to the PM_QOS_CPU_DMA_LATENCY target value.
- */
-int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
-{
-	return blocking_notifier_chain_register(cpu_dma_constraints.notifiers,
-						notifier);
-}
-EXPORT_SYMBOL_GPL(pm_qos_add_notifier);
-
-/**
- * pm_qos_remove_notifier - deletes notification entry from chain.
- * @pm_qos_class: Ignored.
- * @notifier: notifier block to be removed.
- *
- * will remove the notifier from the notification chain that gets called
- * upon changes to the PM_QOS_CPU_DMA_LATENCY target value.
- */
-int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
-{
-	return blocking_notifier_chain_unregister(cpu_dma_constraints.notifiers,
-						  notifier);
-}
-EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
-
 /* User space interface to global PM QoS via misc device. */
 
 static int pm_qos_power_open(struct inode *inode, struct file *filp)
-- 
2.16.4






  parent reply	other threads:[~2020-02-11 23:39 UTC|newest]

Thread overview: 83+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-11 22:51 [PATCH 00/28] PM: QoS: Get rid of unuseful code and rework CPU latency QoS interface Rafael J. Wysocki
2020-02-11 22:52 ` [PATCH 01/28] PM: QoS: Drop debugfs interface Rafael J. Wysocki
2020-02-11 22:58 ` [PATCH 02/28] PM: QoS: Drop pm_qos_update_request_timeout() Rafael J. Wysocki
2020-02-11 22:58 ` [PATCH 03/28] PM: QoS: Drop the PM_QOS_SUM QoS type Rafael J. Wysocki
2020-02-11 22:58 ` [PATCH 04/28] PM: QoS: Clean up pm_qos_update_target() and pm_qos_update_flags() Rafael J. Wysocki
2020-02-11 22:58 ` [PATCH 05/28] PM: QoS: Clean up pm_qos_read_value() and pm_qos_get/set_value() Rafael J. Wysocki
2020-02-11 22:59 ` [PATCH 06/28] PM: QoS: Drop iterations over global QoS classes Rafael J. Wysocki
2020-02-11 23:00 ` [PATCH 07/28] PM: QoS: Clean up misc device file operations Rafael J. Wysocki
2020-02-11 23:01 ` [PATCH 08/28] PM: QoS: Redefine struct pm_qos_request and drop struct pm_qos_object Rafael J. Wysocki
2020-02-11 23:02 ` Rafael J. Wysocki [this message]
2020-02-11 23:04 ` [PATCH 10/28] PM: QoS: Rename things related to the CPU latency QoS Rafael J. Wysocki
2020-02-12 10:34   ` Rafael J. Wysocki
2020-02-12 19:13   ` Greg Kroah-Hartman
2020-02-11 23:06 ` [PATCH 11/28] PM: QoS: Simplify definitions of CPU latency QoS trace events Rafael J. Wysocki
2020-02-11 23:07 ` [PATCH 12/28] PM: QoS: Adjust pm_qos_request() signature and reorder pm_qos.h Rafael J. Wysocki
2020-02-11 23:07 ` [PATCH 13/28] PM: QoS: Add CPU latency QoS API wrappers Rafael J. Wysocki
2020-02-11 23:08 ` [PATCH 14/28] cpuidle: Call cpu_latency_qos_limit() instead of pm_qos_request() Rafael J. Wysocki
2020-02-11 23:10 ` [PATCH 15/28] x86: platform: iosf_mbi: Call cpu_latency_qos_*() instead of pm_qos_*() Rafael J. Wysocki
2020-02-12 10:14   ` Andy Shevchenko
2020-02-11 23:12 ` [PATCH 16/28] drm: i915: " Rafael J. Wysocki
2020-02-11 23:12   ` [Intel-gfx] " Rafael J. Wysocki
2020-02-12 10:32   ` Rafael J. Wysocki
2020-02-12 10:32     ` [Intel-gfx] " Rafael J. Wysocki
2020-02-14  7:42   ` Jani Nikula
2020-02-14  7:42     ` [Intel-gfx] " Jani Nikula
2020-02-11 23:13 ` [PATCH 17/28] drivers: hsi: " Rafael J. Wysocki
2020-02-13 21:06   ` Sebastian Reichel
2020-02-11 23:17 ` [PATCH 18/28] drivers: media: " Rafael J. Wysocki
2020-02-12  5:37   ` Mauro Carvalho Chehab
2020-02-11 23:21 ` [PATCH 19/28] drivers: mmc: " Rafael J. Wysocki
2020-02-11 23:24 ` [PATCH 20/28] drivers: net: " Rafael J. Wysocki
2020-02-11 23:48   ` Jeff Kirsher
2020-02-12  5:49   ` Kalle Valo
2020-02-11 23:26 ` [PATCH 21/28] drivers: spi: " Rafael J. Wysocki
2020-02-11 23:26   ` Rafael J. Wysocki
2020-02-11 23:27 ` [PATCH 22/28] drivers: tty: " Rafael J. Wysocki
2020-02-12 10:35   ` Rafael J. Wysocki
2020-02-12 19:13   ` Greg Kroah-Hartman
2020-02-11 23:28 ` [PATCH 23/28] drivers: usb: " Rafael J. Wysocki
2020-02-12 18:38   ` Greg KH
2020-02-18  8:03     ` Peter Chen
2020-02-18  8:08       ` Greg KH
2020-02-18  8:11         ` Peter Chen
2020-02-19  1:09   ` Peter Chen
2020-02-11 23:34 ` [PATCH 24/28] sound: " Rafael J. Wysocki
2020-02-11 23:34   ` [alsa-devel] " Rafael J. Wysocki
2020-02-12 10:08   ` Mark Brown
2020-02-12 10:08     ` [alsa-devel] " Mark Brown
2020-02-12 10:16     ` Rafael J. Wysocki
2020-02-12 10:16       ` [alsa-devel] " Rafael J. Wysocki
2020-02-12 10:21       ` Takashi Iwai
2020-02-12 10:21         ` [alsa-devel] " Takashi Iwai
2020-02-12 10:18   ` Mark Brown
2020-02-12 10:18     ` [alsa-devel] " Mark Brown
2020-02-11 23:35 ` [PATCH 25/28] PM: QoS: Drop PM_QOS_CPU_DMA_LATENCY and rename related functions Rafael J. Wysocki
2020-02-11 23:35 ` [PATCH 26/28] PM: QoS: Update file information comments Rafael J. Wysocki
2020-02-11 23:36 ` [PATCH 27/28] Documentation: PM: QoS: Update to reflect previous code changes Rafael J. Wysocki
2020-02-11 23:37 ` [PATCH 28/28] PM: QoS: Make CPU latency QoS depend on CONFIG_CPU_IDLE Rafael J. Wysocki
2020-02-12  8:37 ` [PATCH 00/28] PM: QoS: Get rid of unuseful code and rework CPU latency QoS interface Ulf Hansson
2020-02-12  9:17   ` Rafael J. Wysocki
2020-02-12  9:39 ` Rafael J. Wysocki
2020-02-12 23:32 ` Francisco Jerez
2020-02-13  0:16   ` Rafael J. Wysocki
2020-02-13  0:37     ` Rafael J. Wysocki
2020-02-13  8:10       ` Francisco Jerez
2020-02-13 11:38         ` Rafael J. Wysocki
2020-02-21 22:10           ` Francisco Jerez
2020-02-24  0:29             ` Rafael J. Wysocki
2020-02-24 21:06               ` Francisco Jerez
2020-02-13  8:07     ` Francisco Jerez
2020-02-13 11:34       ` Rafael J. Wysocki
2020-02-13 16:35         ` Rafael J. Wysocki
2020-02-14  0:15           ` Francisco Jerez
2020-02-14 10:42             ` Rafael J. Wysocki
2020-02-14 20:32               ` Francisco Jerez
2020-02-24 10:39                 ` Rafael J. Wysocki
2020-02-24 21:16                   ` Francisco Jerez
2020-02-14  0:14         ` Francisco Jerez
2020-02-13  7:10 ` Amit Kucheria
2020-02-13 10:17   ` Rafael J. Wysocki
2020-02-13 10:22     ` Rafael J. Wysocki
2020-02-13 10:49     ` Amit Kucheria
2020-02-13 11:36       ` Rafael J. Wysocki

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