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authorEero Nurkkala <ext-eero.nurkkala@nokia.com>2009-05-25 02:57:37 -0400
committerThomas Gleixner <tglx@linutronix.de>2009-05-27 09:33:43 -0400
commitf2e21c9610991e95621a81407cdbab881226419b (patch)
tree00967210caf3b2ab82d0d0d29da0816d8978b8aa /kernel/time/tick-sched.c
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>
Diffstat (limited to 'kernel/time/tick-sched.c')
-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 d3f1ef4d5cbe..a3562ce54984 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)
222 222
223 cpu = smp_processor_id(); 223 cpu = smp_processor_id();
224 ts = &per_cpu(tick_cpu_sched, cpu); 224 ts = &per_cpu(tick_cpu_sched, cpu);
225
226 /*
227 * Call to tick_nohz_start_idle stops the last_update_time from being
228 * updated. Thus, it must not be called in the event we are called from
229 * irq_exit() with the prior state different than idle.
230 */
231 if (!inidle && !ts->inidle)
232 goto end;
233
225 now = tick_nohz_start_idle(ts); 234 now = tick_nohz_start_idle(ts);
226 235
227 /* 236 /*
@@ -239,9 +248,6 @@ void tick_nohz_stop_sched_tick(int inidle)
239 if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE)) 248 if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE))
240 goto end; 249 goto end;
241 250
242 if (!inidle && !ts->inidle)
243 goto end;
244
245 ts->inidle = 1; 251 ts->inidle = 1;
246 252
247 if (need_resched()) 253 if (need_resched())