Le Wed, Oct 25, 2023 at 10:29:46AM +0800, Z qiang a écrit :
> >
> > Export the RCU point of view as to when a CPU is considered offline
> > (ie: when does RCU consider that a CPU is sufficiently down in the
> > hotplug process to not feature any possible read side).
> >
> > This will be used by RCU-tasks whose vision of an offline CPU should
> > reasonably match the one of RCU core.
> >
> > Fixes: cff9b2332ab7 ("kernel/sched: Modify initial boot task idle setup")
> > Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
> > ---
> > kernel/rcu/rcu.h | 2 ++
> > kernel/rcu/tree.c | 7 +++++++
> > 2 files changed, 9 insertions(+)
> >
> > diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
> > index 0d866eaa4cc8..b531c33e9545 100644
> > --- a/kernel/rcu/rcu.h
> > +++ b/kernel/rcu/rcu.h
> > @@ -500,6 +500,7 @@ static inline void rcu_expedite_gp(void) { }
> > static inline void rcu_unexpedite_gp(void) { }
> > static inline void rcu_async_hurry(void) { }
> > static inline void rcu_async_relax(void) { }
> > +static inline bool rcu_cpu_online(int cpu) { return true; }
> > #else /* #ifdef CONFIG_TINY_RCU */
> > bool rcu_gp_is_normal(void); /* Internal RCU use. */
> > bool rcu_gp_is_expedited(void); /* Internal RCU use. */
> > @@ -509,6 +510,7 @@ void rcu_unexpedite_gp(void);
> > void rcu_async_hurry(void);
> > void rcu_async_relax(void);
> > void rcupdate_announce_bootup_oddness(void);
> > +bool rcu_cpu_online(int cpu);
> > #ifdef CONFIG_TASKS_RCU_GENERIC
> > void show_rcu_tasks_gp_kthreads(void);
> > #else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
> > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> > index 700524726079..fd21c1506092 100644
> > --- a/kernel/rcu/tree.c
> > +++ b/kernel/rcu/tree.c
> > @@ -4202,6 +4202,13 @@ static bool rcu_rdp_cpu_online(struct rcu_data *rdp)
> > return !!(rdp->grpmask & rcu_rnp_online_cpus(rdp->mynode));
> > }
> >
> > +bool rcu_cpu_online(int cpu)
> > +{
> > + struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
> >
> >
>
> Should 'struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu)' be used ?
Oh! Good catch!
>
> Thanks
> Zqiang
>
>
> >
> > +
> > + return rcu_rdp_cpu_online(rdp);
> > +}
> > +
> > #if defined(CONFIG_PROVE_RCU) && defined(CONFIG_HOTPLUG_CPU)
> >
> > /*
> > --
> > 2.41.0
> >
