linux-kernel - [PATCH v6 1/2] PM-runtime: update accounting

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Date:   Tue, 22 Jan 2019 15:24:29 +0100
From:   Vincent Guittot <vincent.guittot@...aro.org>
To:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        rjw@...ysocki.net, thara.gopinath@...aro.org, linux@...ck-us.net
Cc:     ulf.hansson@...aro.org,
        Vincent Guittot <vincent.guittot@...aro.org>
Subject: [PATCH v6 1/2] PM-runtime: update accounting_timestamp only when enable

Initializing accounting_timestamp to something different from 0 during
pm_runtime_init() doesn't make sense and put useless ordering constraint between
timekeeping_init() and pm_runtime_init().
PM runtime should start accounting time only when it is enable and discard
the period when disabled.
Set accounting_timestamp to now when enabling PM runtime.

Suggested-by: "Rafael J. Wysocki" <rjw@...ysocki.net>
Signed-off-by: Vincent Guittot <vincent.guittot@...aro.org>
---
 drivers/base/power/runtime.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index fb5e2b6..7df1d05 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1306,6 +1306,10 @@ void pm_runtime_enable(struct device *dev)
 
 	spin_lock_irqsave(&dev->power.lock, flags);
 
+	/* About to enable runtime pm, set accounting_timestamp to now */
+	if (dev->power.disable_depth == 1)
+		dev->power.accounting_timestamp = jiffies;
+
 	if (dev->power.disable_depth > 0)
 		dev->power.disable_depth--;
 	else
@@ -1506,7 +1510,7 @@ void pm_runtime_init(struct device *dev)
 	dev->power.request_pending = false;
 	dev->power.request = RPM_REQ_NONE;
 	dev->power.deferred_resume = false;
-	dev->power.accounting_timestamp = jiffies;
+	dev->power.accounting_timestamp = 0;
 	INIT_WORK(&dev->power.work, pm_runtime_work);
 
 	dev->power.timer_expires = 0;
-- 
2.7.4