| Message ID | 1328231568-2971-3-git-send-email-paulmck@linux.vnet.ibm.com |
|---|---|
| State | New |
| Headers | show |
On 02/03/2012 06:42 AM, Paul E. McKenney wrote: > From: "Paul E. McKenney" <paul.mckenney@linaro.org> > > The cpuidle_idle_call() function is invoked in the inner idle loop, > after the call to rcu_idle_enter() and before the call to rcu_idle_exit(). > This means that RCU is ignoring the CPU at this point. Unfortunately, > cpuidle_idle_call() nevertheless contains tracepoints (important ones > used by powertop) that expect RCU to be paying attention. The consequences > of using RCU read-side critical sections on CPUs that RCU is ignoring > can be severe, including random corruption of random memory. > > Therefore, this commit uses the new RCU_NONIDLE() macro to let RCU > do its job with respect to the tracepoints. > > Suggested-by: Nicolas Pitre <nicolas.pitre@linaro.org> > Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > Cc: Kevin Hilman <khilman@ti.com> > Cc: Len Brown <len.brown@intel.com> > Cc: Trinabh Gupta <g.trinabh@gmail.com> > Cc: Arjan van de Ven <arjan@linux.intel.com> > Cc: Deepthi Dharwar <deepthi@linux.vnet.ibm.com> > --- > drivers/cpuidle/cpuidle.c | 12 ++++++++---- > 1 files changed, 8 insertions(+), 4 deletions(-) > > diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c > index 59f4261..cd8a553 100644 > --- a/drivers/cpuidle/cpuidle.c > +++ b/drivers/cpuidle/cpuidle.c > @@ -94,13 +94,17 @@ int cpuidle_idle_call(void) > > target_state = &drv->states[next_state]; > > - trace_power_start(POWER_CSTATE, next_state, dev->cpu); > - trace_cpu_idle(next_state, dev->cpu); > + RCU_NONIDLE( > + trace_power_start(POWER_CSTATE, next_state, dev->cpu); > + trace_cpu_idle(next_state, dev->cpu) > + ); > > entered_state = target_state->enter(dev, drv, next_state); > > - trace_power_end(dev->cpu); > - trace_cpu_idle(PWR_EVENT_EXIT, dev->cpu); > + RCU_NONIDLE( > + trace_power_end(dev->cpu); > + trace_cpu_idle(PWR_EVENT_EXIT, dev->cpu); > + ); > > if (entered_state >= 0) { > /* Update cpuidle counters */ Cleaner design esp by moving away from architecture specific tweaking is much appreciated :) Acked-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 59f4261..cd8a553 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -94,13 +94,17 @@ int cpuidle_idle_call(void) target_state = &drv->states[next_state]; - trace_power_start(POWER_CSTATE, next_state, dev->cpu); - trace_cpu_idle(next_state, dev->cpu); + RCU_NONIDLE( + trace_power_start(POWER_CSTATE, next_state, dev->cpu); + trace_cpu_idle(next_state, dev->cpu) + ); entered_state = target_state->enter(dev, drv, next_state); - trace_power_end(dev->cpu); - trace_cpu_idle(PWR_EVENT_EXIT, dev->cpu); + RCU_NONIDLE( + trace_power_end(dev->cpu); + trace_cpu_idle(PWR_EVENT_EXIT, dev->cpu); + ); if (entered_state >= 0) { /* Update cpuidle counters */