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 <inwardvessel@xxxxxxxxx>
---
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
