Re: [PATCH] rcutorture: Make rcutorture support print rcu-tasks gp state

[Paul E. McKenney]

On Sun, Mar 17, 2024 at 03:16:43PM +0800, Z qiang wrote:
> >
> > On Tue, Mar 12, 2024 at 03:23:57PM +0800, Zqiang wrote:
> > > This commit make rcu-tasks related rcutorture test support rcu-tasks
> > > gp state printing when the writer stall occurs or the at the end of
> > > rcutorture test.
> > >
> > > The test is as follows:
> > > [ 3872.548702] tasks-tracing:  Start-test grace-period state: g4560 f0x0
> > > [ 4332.661283] tasks-tracing:  End-test grace-period state: g41540 f0x0 total-gps=36980
> > >
> > > [ 4401.381138] tasks:  Start-test grace-period state: g8 f0x0
> > > [ 4565.619354] tasks:  End-test grace-period state: g1732 f0x0 total-gps=1724
> > >
> > > [ 4589.006917] tasks-rude:  Start-test grace-period state: g8 f0x0
> > > [ 5059.379321] tasks-rude:  End-test grace-period state: g8508 f0x0 total-gps=8500
> > >
> > > Signed-off-by: Zqiang <qiang.zhang1211@xxxxxxxxx>
> >
> > Again, good eyes, and that fix would work.  But wouldn't it make more
> > sense to create a new cur_ops function pointer for these functions?
> > That might allow getting rid of the *_FLAVOR checks and values, plus
> > simplify the code a bit.  To make the function signatures work out,
> > there would need to be an intermediate SRCU function to supply the right
> > rcu_struct pointer.
> >
> > This would shorten and simplify the code a bit.
> >
> > Or is there some reason that this won't work?
> 
> Hi, Paul
> 
> Thanks for your suggestion, I will resend with reference to the
> suggestions above.

Very good, looking forward to seeing it!

							Thanx, Paul

> Thanks
> Zqiang
> 
> 
> >
> > Why didn't I do that to start with?  Well, the various RCU flavors
> > appeared one at a time over some years...  ;-)
> >
> >                                                         Thanx, Paul
> >
> > > ---
> > >  kernel/rcu/rcu.h        |  8 ++++++++
> > >  kernel/rcu/rcutorture.c |  3 +++
> > >  kernel/rcu/tasks.h      | 25 +++++++++++++++++++++++++
> > >  3 files changed, 36 insertions(+)
> > >
> > > diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
> > > index 86fce206560e..3353e3697645 100644
> > > --- a/kernel/rcu/rcu.h
> > > +++ b/kernel/rcu/rcu.h
> > > @@ -556,6 +556,14 @@ static inline unsigned long rcu_get_jiffies_lazy_flush(void) { return 0; }
> > >  static inline void rcu_set_jiffies_lazy_flush(unsigned long j) { }
> > >  #endif
> > >
> > > +#ifdef CONFIG_TASKS_RCU_GENERIC
> > > +void rcutaskstorture_get_gp_data(enum rcutorture_type test_type, int *flags,
> > > +                             unsigned long *gp_seq);
> > > +#else
> > > +static inline void rcutaskstorture_get_gp_data(enum rcutorture_type test_type, int *flags,
> > > +                             unsigned long *gp_seq) { }
> > > +#endif
> > > +
> > >  #if defined(CONFIG_TREE_RCU)
> > >  void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags,
> > >                           unsigned long *gp_seq);
> > > diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
> > > index dd7d5ba45740..91c03f37fd97 100644
> > > --- a/kernel/rcu/rcutorture.c
> > > +++ b/kernel/rcu/rcutorture.c
> > > @@ -2267,6 +2267,7 @@ rcu_torture_stats_print(void)
> > >                                      &flags, &gp_seq);
> > >               srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp,
> > >                                       &flags, &gp_seq);
> > > +             rcutaskstorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
> > >               wtp = READ_ONCE(writer_task);
> > >               pr_alert("??? Writer stall state %s(%d) g%lu f%#x ->state %#x cpu %d\n",
> > >                        rcu_torture_writer_state_getname(),
> > > @@ -3391,6 +3392,7 @@ rcu_torture_cleanup(void)
> > >
> > >       rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
> > >       srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
> > > +     rcutaskstorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
> > >       pr_alert("%s:  End-test grace-period state: g%ld f%#x total-gps=%ld\n",
> > >                cur_ops->name, (long)gp_seq, flags,
> > >                rcutorture_seq_diff(gp_seq, start_gp_seq));
> > > @@ -3763,6 +3765,7 @@ rcu_torture_init(void)
> > >       rcu_torture_print_module_parms(cur_ops, "Start of test");
> > >       rcutorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
> > >       srcutorture_get_gp_data(cur_ops->ttype, srcu_ctlp, &flags, &gp_seq);
> > > +     rcutaskstorture_get_gp_data(cur_ops->ttype, &flags, &gp_seq);
> > >       start_gp_seq = gp_seq;
> > >       pr_alert("%s:  Start-test grace-period state: g%ld f%#x\n",
> > >                cur_ops->name, (long)gp_seq, flags);
> > > diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
> > > index e83adcdb49b5..b1254cf3c210 100644
> > > --- a/kernel/rcu/tasks.h
> > > +++ b/kernel/rcu/tasks.h
> > > @@ -2149,6 +2149,31 @@ late_initcall(rcu_tasks_verify_schedule_work);
> > >  static void rcu_tasks_initiate_self_tests(void) { }
> > >  #endif /* #else #ifdef CONFIG_PROVE_RCU */
> > >
> > > +void rcutaskstorture_get_gp_data(enum rcutorture_type test_type, int *flags,
> > > +                             unsigned long *gp_seq)
> > > +{
> > > +     switch (test_type) {
> > > +     case RCU_TASKS_FLAVOR:
> > > +#ifdef CONFIG_TASKS_RCU
> > > +             *gp_seq = rcu_seq_current(&rcu_tasks.tasks_gp_seq);
> > > +#endif
> > > +             break;
> > > +     case RCU_TASKS_RUDE_FLAVOR:
> > > +#ifdef CONFIG_TASKS_RUDE_RCU
> > > +             *gp_seq = rcu_seq_current(&rcu_tasks_rude.tasks_gp_seq);
> > > +#endif
> > > +             break;
> > > +     case RCU_TASKS_TRACING_FLAVOR:
> > > +#ifdef CONFIG_TASKS_TRACE_RCU
> > > +             *gp_seq = rcu_seq_current(&rcu_tasks_trace.tasks_gp_seq);
> > > +#endif
> > > +             break;
> > > +     default:
> > > +             break;
> > > +     }
> > > +}
> > > +EXPORT_SYMBOL_GPL(rcutaskstorture_get_gp_data);
> > > +
> > >  void __init tasks_cblist_init_generic(void)
> > >  {
> > >       lockdep_assert_irqs_disabled();
> > > --
> > > 2.17.1
> > >