On Fri, Sep 04, 2020 at 10:16:10AM +0800, Boqun Feng wrote: > Hi Paul, > > On Mon, Aug 31, 2020 at 11:14:15AM -0700, paulmck@xxxxxxxxxx wrote: > > From: "Paul E. McKenney" <paulmck@xxxxxxxxxx> > > > > This commit adds a destination CPU to __call_single_data, and is inspired > > by an earlier commit by Peter Zijlstra. This version adds #ifdef to > > permit use by 32-bit systems and supplying the destination CPU for all > > smp_call_function*() requests, not just smp_call_function_single(). > > > > If need be, 32-bit systems could be accommodated by shrinking the flags > > field to 16 bits (the atomic_t variant is currently unused) and by > > providing only eight bits for CPU on such systems. > > > > It is not clear that the addition of the fields to __call_single_node > > are really needed. > > > > Link: https://lore.kernel.org/lkml/20200615164048.GC2531@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ > > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > > Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> > > Cc: Frederic Weisbecker <frederic@xxxxxxxxxx> > > Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> > > --- > > include/linux/smp.h | 3 +++ > > include/linux/smp_types.h | 3 +++ > > kernel/smp.c | 2 ++ > > 3 files changed, 8 insertions(+) > > > > diff --git a/include/linux/smp.h b/include/linux/smp.h > > index 80d557e..9f13966 100644 > > --- a/include/linux/smp.h > > +++ b/include/linux/smp.h > > @@ -26,6 +26,9 @@ struct __call_single_data { > > struct { > > struct llist_node llist; > > unsigned int flags; > > +#ifdef CONFIG_64BIT > > + u16 src, dst; > > +#endif > > }; > > }; > > smp_call_func_t func; > > diff --git a/include/linux/smp_types.h b/include/linux/smp_types.h > > index 364b3ae..2e8461a 100644 > > --- a/include/linux/smp_types.h > > +++ b/include/linux/smp_types.h > > @@ -61,6 +61,9 @@ struct __call_single_node { > > unsigned int u_flags; > > atomic_t a_flags; > > }; > > +#ifdef CONFIG_64BIT > > + u16 src, dst; > > +#endif > > }; > > > > #endif /* __LINUX_SMP_TYPES_H */ > > diff --git a/kernel/smp.c b/kernel/smp.c > > index d0ae8eb..a47382d 100644 > > --- a/kernel/smp.c > > +++ b/kernel/smp.c > > @@ -375,6 +375,7 @@ int smp_call_function_single(int cpu, smp_call_func_t func, void *info, > > > > csd->func = func; > > csd->info = info; > > + csd->dst = cpu; > > Would this and the next modification cause compile errors with > CONFIG_64BIT = n? I saw you add #ifdef guard in the next patch, so maybe > move those two into next patch (of course, if they trigger compile > errors) Good point, will fix, thank you! Thanx, Paul > Regards, > Boqun > > > > > err = generic_exec_single(cpu, csd); > > > > @@ -540,6 +541,7 @@ static void smp_call_function_many_cond(const struct cpumask *mask, > > csd->flags |= CSD_TYPE_SYNC; > > csd->func = func; > > csd->info = info; > > + csd->dst = cpu; > > if (llist_add(&csd->llist, &per_cpu(call_single_queue, cpu))) > > __cpumask_set_cpu(cpu, cfd->cpumask_ipi); > > } > > -- > > 2.9.5 > >
