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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux PM list <linux-pm@vger.kernel.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Juri Lelli <juri.lelli@arm.com>,
	Shilpasri G Bhat <shilpabhatppc@gmail.com>
Subject: [PATCH 1/2] cpufreq: governor: Simplify gov_cancel_work() slightly
Date: Fri, 12 Feb 2016 14:28:13 +0100	[thread overview]
Message-ID: <2337921.T3qTZn9cXM@vostro.rjw.lan> (raw)
In-Reply-To: <5225538.XnBMjjCp2q@vostro.rjw.lan>

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

The atomic work counter incrementation in gov_cancel_work() is not
necessary any more, because work items won't be queued up after
gov_clear_update_util() anyway, so drop it along with the comment
about how it may be missed by the gov_clear_update_util().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/cpufreq/cpufreq_governor.c |    8 --------
 1 file changed, 8 deletions(-)

Index: linux-pm/drivers/cpufreq/cpufreq_governor.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq_governor.c
+++ linux-pm/drivers/cpufreq/cpufreq_governor.c
@@ -195,13 +195,6 @@ static inline void gov_clear_update_util
 
 static void gov_cancel_work(struct policy_dbs_info *policy_dbs)
 {
-	/* Tell dbs_update_util_handler() to skip queuing up work items. */
-	atomic_inc(&policy_dbs->work_count);
-	/*
-	 * If dbs_update_util_handler() is already running, it may not notice
-	 * the incremented work_count, so wait for it to complete to prevent its
-	 * work item from being queued up after the cancel_work_sync() below.
-	 */
 	gov_clear_update_util(policy_dbs->policy);
 	irq_work_sync(&policy_dbs->irq_work);
 	cancel_work_sync(&policy_dbs->work);
@@ -264,7 +257,6 @@ static void dbs_update_util_handler(stru
 	 * The work may not be allowed to be queued up right now.
 	 * Possible reasons:
 	 * - Work has already been queued up or is in progress.
-	 * - The governor is being stopped.
 	 * - It is too early (too little time from the previous sample).
 	 */
 	if (atomic_inc_return(&policy_dbs->work_count) == 1) {

  reply	other threads:[~2016-02-12 13:32 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-12 13:26 [PATCH 0/2] cpufreq: governor: Optimize work queuing in ondemand/conservative Rafael J. Wysocki
2016-02-12 13:28 ` Rafael J. Wysocki [this message]
2016-02-12 13:33 ` [PATCH 2/2] cpufreq: governor: Avoid atomic operations in hot paths Rafael J. Wysocki

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