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List:       git-commits-head
Subject:    Revert "cpufreq: governor: Fix negative idle_time when configured with CONFIG_HZ_PERIODIC"
From:       "Linux Kernel Mailing List" <linux-kernel () vger ! kernel ! org>
Date:       2016-04-30 0:48:59
Message-ID: 20160430004859.B98C4660F83 () gitolite ! kernel ! org
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Web:        https://git.kernel.org/torvalds/c/94862a62dfe3ba1c7601115a2dc80721c5b256f0
                
Commit:     94862a62dfe3ba1c7601115a2dc80721c5b256f0
Parent:     c9d9c929e6741118776eb0f385339d3c2b84d5f8
Refname:    refs/heads/master
Author:     Rafael J. Wysocki <rafael.j.wysocki@intel.com>
AuthorDate: Thu Apr 21 20:57:47 2016 +0200
Committer:  Rafael J. Wysocki <rafael.j.wysocki@intel.com>
CommitDate: Mon Apr 25 02:39:20 2016 +0200

    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>
---
 drivers/cpufreq/cpufreq_governor.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index 10a5cfe..5f1147f 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];
--
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