On Fri, May 01, 2020 at 12:05:55PM -0700, Paul E. McKenney wrote:
> On Tue, Apr 28, 2020 at 10:58:42PM +0200, Uladzislau Rezki (Sony) wrote:
> > From: "Joel Fernandes (Google)" <joel@xxxxxxxxxxxxxxxxx>
> >
> > Simple clean up of comments in kfree_rcu() code to keep it consistent
> > with majority of commenting styles.
> >
> > Reviewed-by: Uladzislau Rezki <urezki@xxxxxxxxx>
> > Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
> > Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
>
> Hmmm...
>
> Exactly why is three additional characters per line preferable? Or in
> the case of block comments, either one or two additional lines, depending
> on /* */ style?
I prefer to keep the code consistent and then bulk convert it later. Its a
bit ugly to read when its mixed up with "//" and "/* */" right now. We can
convert it to // all at once later but until then it'll be good to keep it
consistent in this file IMO. When I checked the kfree_rcu() code, it had more
"/* */" than not, so this small change is less churn for now.
thanks,
- Joel
>
> I am (slowly) moving RCU to "//" for those reasons. ;-)
>
> Thanx, Paul
>
> > ---
> > kernel/rcu/tree.c | 16 ++++++++--------
> > 1 file changed, 8 insertions(+), 8 deletions(-)
> >
> > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> > index cd61649e1b00..1487af8e11e8 100644
> > --- a/kernel/rcu/tree.c
> > +++ b/kernel/rcu/tree.c
> > @@ -3043,15 +3043,15 @@ static inline bool queue_kfree_rcu_work(struct kfree_rcu_cpu *krcp)
> > static inline void kfree_rcu_drain_unlock(struct kfree_rcu_cpu *krcp,
> > unsigned long flags)
> > {
> > - // Attempt to start a new batch.
> > + /* Attempt to start a new batch. */
> > krcp->monitor_todo = false;
> > if (queue_kfree_rcu_work(krcp)) {
> > - // Success! Our job is done here.
> > + /* Success! Our job is done here. */
> > raw_spin_unlock_irqrestore(&krcp->lock, flags);
> > return;
> > }
> >
> > - // Previous RCU batch still in progress, try again later.
> > + /* Previous RCU batch still in progress, try again later. */
> > krcp->monitor_todo = true;
> > schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES);
> > raw_spin_unlock_irqrestore(&krcp->lock, flags);
> > @@ -3151,14 +3151,14 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> > unsigned long flags;
> > struct kfree_rcu_cpu *krcp;
> >
> > - local_irq_save(flags); // For safely calling this_cpu_ptr().
> > + local_irq_save(flags); /* For safely calling this_cpu_ptr(). */
> > krcp = this_cpu_ptr(&krc);
> > if (krcp->initialized)
> > raw_spin_lock(&krcp->lock);
> >
> > - // Queue the object but don't yet schedule the batch.
> > + /* Queue the object but don't yet schedule the batch. */
> > if (debug_rcu_head_queue(head)) {
> > - // Probable double kfree_rcu(), just leak.
> > + /* Probable double kfree_rcu(), just leak. */
> > WARN_ONCE(1, "%s(): Double-freed call. rcu_head %p\n",
> > __func__, head);
> > goto unlock_return;
> > @@ -3176,7 +3176,7 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
> >
> > WRITE_ONCE(krcp->count, krcp->count + 1);
> >
> > - // Set timer to drain after KFREE_DRAIN_JIFFIES.
> > + /* Set timer to drain after KFREE_DRAIN_JIFFIES. */
> > if (rcu_scheduler_active == RCU_SCHEDULER_RUNNING &&
> > !krcp->monitor_todo) {
> > krcp->monitor_todo = true;
> > @@ -3722,7 +3722,7 @@ int rcutree_offline_cpu(unsigned int cpu)
> >
> > rcutree_affinity_setting(cpu, cpu);
> >
> > - // nohz_full CPUs need the tick for stop-machine to work quickly
> > + /* nohz_full CPUs need the tick for stop-machine to work quickly */
> > tick_dep_set(TICK_DEP_BIT_RCU);
> > return 0;
> > }
> > --
> > 2.20.1
> >
