[02/12] srcu: Introduce srcu_gp_is_expedited() helper function

Commit Message

Paul E. McKenney Oct. 9, 2024, 6:07 p.m. UTC

Even though the open-coded expressions usually fit on one line, this
commit replaces them with a call to a new srcu_gp_is_expedited()
helper function in order to improve readability.

Signed-off-by: Paul E. McKenney <[e-mail]>
Cc: Alexei Starovoitov <[e-mail]>
Cc: Andrii Nakryiko <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Kent Overstreet <[e-mail]>
Cc: <[e-mail]>
---
 kernel/rcu/srcutree.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

Comments

Neeraj Upadhyay Oct. 14, 2024, 8:57 a.m. UTC | #1

On 10/9/2024 11:37 PM, Paul E. McKenney wrote:
> Even though the open-coded expressions usually fit on one line, this
> commit replaces them with a call to a new srcu_gp_is_expedited()
> helper function in order to improve readability.
> 
> Signed-off-by: Paul E. McKenney <[e-mail]>
> Cc: Alexei Starovoitov <[e-mail]>
> Cc: Andrii Nakryiko <[e-mail]>
> Cc: Peter Zijlstra <[e-mail]>
> Cc: Kent Overstreet <[e-mail]>
> Cc: <[e-mail]>
> ---

Reviewed-by: Neeraj Upadhyay <[e-mail]>


- Neeraj

Patch

diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index 9ff4ded609ba5..e29c6cbffbcb0 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -418,6 +418,16 @@  static void check_init_srcu_struct(struct srcu_struct *ssp)
 	spin_unlock_irqrestore_rcu_node(ssp->srcu_sup, flags);
 }
 
+/*
+ * Is the current or any upcoming grace period to be expedited?
+ */
+static bool srcu_gp_is_expedited(struct srcu_struct *ssp)
+{
+	struct srcu_usage *sup = ssp->srcu_sup;
+
+	return ULONG_CMP_LT(READ_ONCE(sup->srcu_gp_seq), READ_ONCE(sup->srcu_gp_seq_needed_exp));
+}
+
 /*
  * Returns approximate total of the readers' ->srcu_lock_count[] values
  * for the rank of per-CPU counters specified by idx.
@@ -622,7 +632,7 @@  static unsigned long srcu_get_delay(struct srcu_struct *ssp)
 	unsigned long jbase = SRCU_INTERVAL;
 	struct srcu_usage *sup = ssp->srcu_sup;
 
-	if (ULONG_CMP_LT(READ_ONCE(sup->srcu_gp_seq), READ_ONCE(sup->srcu_gp_seq_needed_exp)))
+	if (srcu_gp_is_expedited(ssp))
 		jbase = 0;
 	if (rcu_seq_state(READ_ONCE(sup->srcu_gp_seq))) {
 		j = jiffies - 1;
@@ -867,7 +877,7 @@  static void srcu_gp_end(struct srcu_struct *ssp)
 	spin_lock_irq_rcu_node(sup);
 	idx = rcu_seq_state(sup->srcu_gp_seq);
 	WARN_ON_ONCE(idx != SRCU_STATE_SCAN2);
-	if (ULONG_CMP_LT(READ_ONCE(sup->srcu_gp_seq), READ_ONCE(sup->srcu_gp_seq_needed_exp)))
+	if (srcu_gp_is_expedited(ssp))
 		cbdelay = 0;
 
 	WRITE_ONCE(sup->srcu_last_gp_end, ktime_get_mono_fast_ns());