On Thu, Aug 30, 2012 at 02:05:35PM -0700, Paul E. McKenney wrote: > From: Frederic Weisbecker <[email protected]> > > In the old times, the whole idle task was considered > as an RCU quiescent state. But as RCU became more and > more successful overtime, some RCU read side critical > section have been added even in the code of some > architectures idle tasks, for tracing for example. > > So nowadays, rcu_idle_enter() and rcu_idle_exit() must > be called by the architecture to tell RCU about the part > in the idle loop that doesn't make use of rcu read side > critical sections, typically the part that puts the CPU > in low power mode. > > This is necessary for RCU to find the quiescent states in > idle in order to complete grace periods. > > Add this missing pair of calls in the Frv's idle loop. > > Reported-by: Paul E. McKenney <[email protected]> > Signed-off-by: Frederic Weisbecker <[email protected]> > Cc: David Howells <[email protected]> > Cc: 3.2.x.. <[email protected]> > Cc: Paul E. McKenney <[email protected]>
Reviewed-by: Josh Triplett <[email protected]> > arch/frv/kernel/process.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/arch/frv/kernel/process.c b/arch/frv/kernel/process.c > index ff95f50..2eb7fa5 100644 > --- a/arch/frv/kernel/process.c > +++ b/arch/frv/kernel/process.c > @@ -25,6 +25,7 @@ > #include <linux/reboot.h> > #include <linux/interrupt.h> > #include <linux/pagemap.h> > +#include <linux/rcupdate.h> > > #include <asm/asm-offsets.h> > #include <asm/uaccess.h> > @@ -69,12 +70,14 @@ void cpu_idle(void) > { > /* endless idle loop with no priority at all */ > while (1) { > + rcu_idle_enter(); > while (!need_resched()) { > check_pgt_cache(); > > if (!frv_dma_inprogress && idle) > idle(); > } > + rcu_idle_exit(); > > schedule_preempt_disabled(); > } > -- > 1.7.8 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
