| Message ID | 1346360743-3628-22-git-send-email-paulmck@linux.vnet.ibm.com |
|---|---|
| State | Accepted |
| Commit | 5b0753a90b7a98bc613c3767e9263a1a76d4f900 |
| Headers | show |
On Thu, Aug 30, 2012 at 02:05:39PM -0700, Paul E. McKenney wrote: > From: Frederic Weisbecker <fweisbec@gmail.com> > > 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 mn10300's idle loop. > > Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> > Cc: David Howells <dhowells@redhat.com> > Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> > Cc: 3.2.x.. <stable@vger.kernel.org> > Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> > arch/mn10300/kernel/process.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/arch/mn10300/kernel/process.c b/arch/mn10300/kernel/process.c > index 7dab0cd..e9cceba 100644 > --- a/arch/mn10300/kernel/process.c > +++ b/arch/mn10300/kernel/process.c > @@ -25,6 +25,7 @@ > #include <linux/err.h> > #include <linux/fs.h> > #include <linux/slab.h> > +#include <linux/rcupdate.h> > #include <asm/uaccess.h> > #include <asm/pgtable.h> > #include <asm/io.h> > @@ -107,6 +108,7 @@ void cpu_idle(void) > { > /* endless idle loop with no priority at all */ > for (;;) { > + rcu_idle_enter(); > while (!need_resched()) { > void (*idle)(void); > > @@ -121,6 +123,7 @@ void cpu_idle(void) > } > idle(); > } > + rcu_idle_exit(); > > schedule_preempt_disabled(); > } > -- > 1.7.8 >
diff --git a/arch/mn10300/kernel/process.c b/arch/mn10300/kernel/process.c index 7dab0cd..e9cceba 100644 --- a/arch/mn10300/kernel/process.c +++ b/arch/mn10300/kernel/process.c @@ -25,6 +25,7 @@ #include <linux/err.h> #include <linux/fs.h> #include <linux/slab.h> +#include <linux/rcupdate.h> #include <asm/uaccess.h> #include <asm/pgtable.h> #include <asm/io.h> @@ -107,6 +108,7 @@ void cpu_idle(void) { /* endless idle loop with no priority at all */ for (;;) { + rcu_idle_enter(); while (!need_resched()) { void (*idle)(void); @@ -121,6 +123,7 @@ void cpu_idle(void) } idle(); } + rcu_idle_exit(); schedule_preempt_disabled(); }