On Mon, Jul 15, 2024 at 04:23:24PM -0700, JP Kobryn wrote: > Using a higher value for the initial gp sequence counters allows for > wrapping to occur faster. It can help with surfacing any issues that may > be happening as a result of the wrap around. > > Signed-off-by: JP Kobryn <[email protected]>
Much nicer, thank you! Tested-by: Paul E. McKenney <[email protected]> > --- > kernel/rcu/srcutree.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c > index bc4b58b0204e..907c4a484503 100644 > --- a/kernel/rcu/srcutree.c > +++ b/kernel/rcu/srcutree.c > @@ -30,6 +30,9 @@ > #include "rcu.h" > #include "rcu_segcblist.h" > > +/* Start with a gp sequence value that allows wrapping to occur faster. */ > +#define SRCU_GP_SEQ_INITIAL_VAL ((0UL - 100UL) << RCU_SEQ_CTR_SHIFT) > + > /* Holdoff in nanoseconds for auto-expediting. */ > #define DEFAULT_SRCU_EXP_HOLDOFF (25 * 1000) > static ulong exp_holdoff = DEFAULT_SRCU_EXP_HOLDOFF; > @@ -247,7 +250,7 @@ static int init_srcu_struct_fields(struct srcu_struct > *ssp, bool is_static) > mutex_init(&ssp->srcu_sup->srcu_cb_mutex); > mutex_init(&ssp->srcu_sup->srcu_gp_mutex); > ssp->srcu_idx = 0; > - ssp->srcu_sup->srcu_gp_seq = 0; > + ssp->srcu_sup->srcu_gp_seq = SRCU_GP_SEQ_INITIAL_VAL; > ssp->srcu_sup->srcu_barrier_seq = 0; > mutex_init(&ssp->srcu_sup->srcu_barrier_mutex); > atomic_set(&ssp->srcu_sup->srcu_barrier_cpu_cnt, 0); > @@ -258,7 +261,7 @@ static int init_srcu_struct_fields(struct srcu_struct > *ssp, bool is_static) > if (!ssp->sda) > goto err_free_sup; > init_srcu_struct_data(ssp); > - ssp->srcu_sup->srcu_gp_seq_needed_exp = 0; > + ssp->srcu_sup->srcu_gp_seq_needed_exp = SRCU_GP_SEQ_INITIAL_VAL; > ssp->srcu_sup->srcu_last_gp_end = ktime_get_mono_fast_ns(); > if (READ_ONCE(ssp->srcu_sup->srcu_size_state) == SRCU_SIZE_SMALL && > SRCU_SIZING_IS_INIT()) { > if (!init_srcu_struct_nodes(ssp, GFP_ATOMIC)) > @@ -266,7 +269,8 @@ static int init_srcu_struct_fields(struct srcu_struct > *ssp, bool is_static) > WRITE_ONCE(ssp->srcu_sup->srcu_size_state, SRCU_SIZE_BIG); > } > ssp->srcu_sup->srcu_ssp = ssp; > - smp_store_release(&ssp->srcu_sup->srcu_gp_seq_needed, 0); /* Init done. > */ > + smp_store_release(&ssp->srcu_sup->srcu_gp_seq_needed, > + SRCU_GP_SEQ_INITIAL_VAL); /* Init done. */ > return 0; > > err_free_sda: > -- > 2.45.2 >
