On 10/3/2026 12:17 PM, Kunwu Chan wrote: > Add support for scaling atomic SRCU grace periods using > srcu_read_lock_atomic()/srcu_read_unlock_atomic() and > synchronize_srcu_atomic(). > > Suggested-by: Paul E. McKenney <[email protected]> > Signed-off-by: Kunwu Chan <[email protected]> > --- > Changes since v1: > - Rename srcu_atomic_ctlp to srcua and reuse srcu_ctlp for > SRCU operations, as suggested by Paul. > - Reuse the existing SRCU cleanup and completed helpers by > initializing srcu_ctlp in srcu_atomic_scale_init(). > - Add .stats using srcu_scale_stats(). > - Use "srcua" to match the existing "srcu" and "srcud" scale > type names. > - Use synchronize_srcu_atomic() for both normal and expedited > scale tests. > > v1: https://lore.kernel.org/all/[email protected]/ > Tested with kvm.sh --torture rcuscale scale_type=srcua on x86_64 and > arm64, alongside gp_exp=1 and PROVE_LOCKING=y: no warnings or lockdep > splats. > ---
Maybe some performance numbers too for an rcuscale patch? ;-) But either way: Reviewed-by: Joel Fernandes <[email protected]> > kernel/rcu/rcuscale.c | 41 ++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 40 insertions(+), 1 deletion(-) > > diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c > index 1097ec15879c..b172882824ac 100644 > --- a/kernel/rcu/rcuscale.c > +++ b/kernel/rcu/rcuscale.c > @@ -293,6 +293,44 @@ static struct rcu_scale_ops srcud_ops = { > .name = "srcud" > }; > > +static struct srcu_struct srcua; > + > +static int srcu_scale_atomic_read_lock(void) > +{ > + return srcu_read_lock_atomic(srcu_ctlp); > +} > + > +static void srcu_scale_atomic_read_unlock(int idx) > +{ > + srcu_read_unlock_atomic(srcu_ctlp, idx); > +} > + > +static void srcu_scale_atomic_synchronize(void) > +{ > + synchronize_srcu_atomic(srcu_ctlp); > +} > + > +static void srcu_atomic_scale_init(void) > +{ > + srcu_ctlp = &srcua; > + init_srcu_struct_atomic(srcu_ctlp); > +} > + > +static struct rcu_scale_ops srcua_ops = { > + .ptype = SRCU_FLAVOR, > + .init = srcu_atomic_scale_init, > + .cleanup = srcu_sync_scale_cleanup, > + .readlock = srcu_scale_atomic_read_lock, > + .readunlock = srcu_scale_atomic_read_unlock, > + .get_gp_seq = srcu_scale_completed, > + .gp_diff = rcu_seq_diff, > + .exp_completed = srcu_scale_completed, > + .sync = srcu_scale_atomic_synchronize, > + .exp_sync = srcu_scale_atomic_synchronize, > + .stats = srcu_scale_stats, > + .name = "srcua" > +}; > + > #ifdef CONFIG_TASKS_RCU > > /* > @@ -1110,7 +1148,8 @@ rcu_scale_init(void) > long i; > long j; > static struct rcu_scale_ops *scale_ops[] = { > - &rcu_ops, &srcu_ops, &srcud_ops, TASKS_OPS TASKS_RUDE_OPS > TASKS_TRACING_OPS > + &rcu_ops, &srcu_ops, &srcua_ops, &srcud_ops, > + TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS > }; > > if (!torture_init_begin(scale_type, verbose)) > > base-commit: d21906b0aa1e9573cdb5e7acaca44966b9d1dcd2 -- Joel Fernandes
