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authorJoel Fernandes <joelaf@google.com>2017-12-21 02:22:45 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-12-28 12:26:54 +0100
commit466a2b42d67644447a1765276259a3ea5531ddff (patch)
treeca896ab907badd58efe681d139fdcecab1491c70 /kernel/time
parent464e1d5f23cca236b930ef068c328a64cab78fb1 (diff)
downloadlinux-466a2b42d67644447a1765276259a3ea5531ddff.tar.bz2
cpufreq: schedutil: Use idle_calls counter of the remote CPU
Since the recent remote cpufreq callback work, its possible that a cpufreq update is triggered from a remote CPU. For single policies however, the current code uses the local CPU when trying to determine if the remote sg_cpu entered idle or is busy. This is incorrect. To remedy this, compare with the nohz tick idle_calls counter of the remote CPU. Fixes: 674e75411fc2 (sched: cpufreq: Allow remote cpufreq callbacks) Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Joel Fernandes <joelaf@google.com> Cc: 4.14+ <stable@vger.kernel.org> # 4.14+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/tick-sched.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 99578f06c8d4..77555faf6fbc 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -986,6 +986,19 @@ ktime_t tick_nohz_get_sleep_length(void)
}
/**
+ * tick_nohz_get_idle_calls_cpu - return the current idle calls counter value
+ * for a particular CPU.
+ *
+ * Called from the schedutil frequency scaling governor in scheduler context.
+ */
+unsigned long tick_nohz_get_idle_calls_cpu(int cpu)
+{
+ struct tick_sched *ts = tick_get_tick_sched(cpu);
+
+ return ts->idle_calls;
+}
+
+/**
* tick_nohz_get_idle_calls - return the current idle calls counter value
*
* Called from the schedutil frequency scaling governor in scheduler context.