On Fri, Apr 02, 2021 at 02:58:13AM +0200, Frederic Weisbecker wrote:
> On Thu, Apr 01, 2021 at 05:48:56PM -0700, Paul E. McKenney wrote:
> > On Fri, Apr 02, 2021 at 01:47:02AM +0200, Frederic Weisbecker wrote:
> > > When an ssp has already started a grace period and queued an early work
> > > to flush after SRCU workqueues are created, we expect the ssp to be
> > > properly initialized already. So we can skip this step at this stage.
> > >
> > > Signed-off-by: Frederic Weisbecker <frede...@kernel.org>
> > > Cc: Boqun Feng <boqun.f...@gmail.com>
> > > Cc: Lai Jiangshan <jiangshan...@gmail.com>
> > > Cc: Neeraj Upadhyay <neer...@codeaurora.org>
> > > Cc: Josh Triplett <j...@joshtriplett.org>
> > > Cc: Joel Fernandes <j...@joelfernandes.org>
> > > Cc: Uladzislau Rezki <ure...@gmail.com>
> > > ---
> > > kernel/rcu/srcutree.c | 1 -
> > > 1 file changed, 1 deletion(-)
> > >
> > > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
> > > index 036ff5499ad5..7197156418e4 100644
> > > --- a/kernel/rcu/srcutree.c
> > > +++ b/kernel/rcu/srcutree.c
> > > @@ -1396,7 +1396,6 @@ void __init srcu_init(void)
> > > while (!list_empty(&srcu_boot_list)) {
> > > ssp = list_first_entry(&srcu_boot_list, struct srcu_struct,
> > > work.work.entry);
> > > - check_init_srcu_struct(ssp);
> >
> > You lost me on this one. What happens if the only pre-initialization
> > invocation on the statically allocated srcu_struct pointed to by ssp
> > was call_srcu()? I am not seeing how the initialization has already
> > happened in that case.
> >
> > What am I missing here?
>
> call_srcu() -> __call_srcu() -> srcu_gp_start_if_needed() ->
> check_init_srcu_struct() ?
>
> Or is it me missing something?
Nope, me getting confused between Tree SRCU's and Tiny SRCU's
call_srcu() implementation. :-/
I have queued this patch and started testing.
Thanx, Paul
