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authorEero Nurkkala <ext-eero.nurkkala@nokia.com>2009-05-25 09:57:37 +0300
committerThomas Gleixner <tglx@linutronix.de>2009-05-27 15:33:43 +0200
commitf2e21c9610991e95621a81407cdbab881226419b (patch)
tree00967210caf3b2ab82d0d0d29da0816d8978b8aa
parentcd86a536c81e9300d984327517548ca0652eebf9 (diff)
NOHZ: Properly feed cpufreq ondemand governor
A call from irq_exit() may occasionally pause the timing info for cpufreq ondemand governor. This results in the cpufreq ondemand governor to fail to calculate the system load properly. Thus, relocate the checks for this particular case to keep the governor always functional. Signed-off-by: Eero Nurkkala <ext-eero.nurkkala@nokia.com> Reported-by: Tero Kristo <tero.kristo@nokia.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--kernel/time/tick-sched.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index d3f1ef4d5cb..a3562ce5498 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -222,6 +222,15 @@ void tick_nohz_stop_sched_tick(int inidle)
cpu = smp_processor_id();
ts = &per_cpu(tick_cpu_sched, cpu);
+
+ /*
+ * Call to tick_nohz_start_idle stops the last_update_time from being
+ * updated. Thus, it must not be called in the event we are called from
+ * irq_exit() with the prior state different than idle.
+ */
+ if (!inidle && !ts->inidle)
+ goto end;
+
now = tick_nohz_start_idle(ts);
/*
@@ -239,9 +248,6 @@ void tick_nohz_stop_sched_tick(int inidle)
if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE))
goto end;
- if (!inidle && !ts->inidle)
- goto end;
-
ts->inidle = 1;
if (need_resched())