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From: <gregkh@linuxfoundation.org>
To: rafael.j.wysocki@intel.com, stable@vger.kernel.org,
	timo.valtoaho@gmail.com, viresh.kumar@linaro.org
Cc: <stable@vger.kernel.org>
Subject: FAILED: patch "[PATCH] Revert "cpufreq: governor: Fix negative idle_time when" failed to apply to 4.5-stable tree
Date: Sun, 01 May 2016 15:01:10 -0700	[thread overview]
Message-ID: <1462140070210102@kroah.com> (raw)


The patch below does not apply to the 4.5-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From 94862a62dfe3ba1c7601115a2dc80721c5b256f0 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Date: Thu, 21 Apr 2016 20:57:47 +0200
Subject: [PATCH] Revert "cpufreq: governor: Fix negative idle_time when
 configured with CONFIG_HZ_PERIODIC"

Revert commit 0df35026c6a5 (cpufreq: governor: Fix negative idle_time
when configured with CONFIG_HZ_PERIODIC) that introduced a regression
by causing the ondemand cpufreq governor to misbehave for
CONFIG_TICK_CPU_ACCOUNTING unset (the frequency goes up to the max at
one point and stays there indefinitely).

The revert takes subsequent modifications of the code in question into
account.

Fixes: 0df35026c6a5 (cpufreq: governor: Fix negative idle_time when configured with CONFIG_HZ_PERIODIC)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=115261
Reported-and-tested-by: Timo Valtoaho <timo.valtoaho@gmail.com>
Cc: 4.5+ <stable@vger.kernel.org> # 4.5+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index 10a5cfeae8c5..5f1147fa9239 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -193,12 +193,8 @@ unsigned int dbs_update(struct cpufreq_policy *policy)
 		wall_time = cur_wall_time - j_cdbs->prev_cpu_wall;
 		j_cdbs->prev_cpu_wall = cur_wall_time;
 
-		if (cur_idle_time <= j_cdbs->prev_cpu_idle) {
-			idle_time = 0;
-		} else {
-			idle_time = cur_idle_time - j_cdbs->prev_cpu_idle;
-			j_cdbs->prev_cpu_idle = cur_idle_time;
-		}
+		idle_time = cur_idle_time - j_cdbs->prev_cpu_idle;
+		j_cdbs->prev_cpu_idle = cur_idle_time;
 
 		if (ignore_nice) {
 			u64 cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE];


                 reply	other threads:[~2016-05-01 22:01 UTC|newest]

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