linux-kernel - [PATCH v11 4/8] cpuidle: menu: Convert to tick_nohz_get_next

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Date:   Tue, 26 Feb 2019 15:54:11 +0100
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     "Rafael J . Wysocki" <rjw@...ysocki.net>, linux-pm@...r.kernel.org
Cc:     Frederic Weisbecker <fweisbec@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Sudeep Holla <sudeep.holla@....com>,
        Lorenzo Pieralisi <Lorenzo.Pieralisi@....com>,
        Mark Rutland <mark.rutland@....com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        "Raju P . L . S . S . S . N" <rplsssn@...eaurora.org>,
        Stephen Boyd <sboyd@...nel.org>,
        Tony Lindgren <tony@...mide.com>,
        Kevin Hilman <khilman@...nel.org>,
        Lina Iyer <ilina@...eaurora.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v11 4/8] cpuidle: menu: Convert to tick_nohz_get_next_timer|hrtimer()

From: Daniel Lezcano <daniel.lezcano@...aro.org>

Rather than using tick_nohz_get_sleep_length(), let's convert to use the
more flexible tick_nohz_get_next_timer|hrtimer() APIs. This should have no
functional change, but allows following changes to later drop the
tick_nohz_get_sleep_length() API.

Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
[Ulf: Clarified information in changelog]
Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
---

Changes in v11:
	- New patch.

---
 drivers/cpuidle/governors/menu.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 61316fc51548..95e9122d6047 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -286,14 +286,26 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev,
 	unsigned int predicted_us;
 	unsigned long nr_iowaiters;
 	ktime_t delta_next;
+	ktime_t now = ktime_get();
+	ktime_t next_hrtimer = tick_nohz_get_next_hrtimer();
+	ktime_t next_timer = tick_nohz_get_next_timer();
 
 	if (data->needs_update) {
 		menu_update(drv, dev);
 		data->needs_update = 0;
 	}
 
-	/* determine the expected residency time, round up */
-	data->next_timer_us = ktime_to_us(tick_nohz_get_sleep_length(&delta_next));
+	/*
+	 * Compute the duration before the next timer, whatever the origin
+	 */
+	delta_next = ktime_sub(next_timer, now);
+	data->next_timer_us = ktime_to_us(delta_next);
+
+	/*
+	 * Compute the duration before next hrtimer which is the tick
+	 * or an earliest hrtimer
+	 */
+	delta_next = ktime_sub(next_hrtimer, now);
 
 	nr_iowaiters = nr_iowait_cpu(dev->cpu);
 	data->bucket = which_bucket(data->next_timer_us, nr_iowaiters);
-- 
2.17.1