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From: "Paul E. McKenney" <paulmck@kernel.org>
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com,
	rostedt@goodmis.org, Alexei Starovoitov <ast@kernel.org>,
	Andrii Nakryiko <andrii@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Kent Overstreet <kent.overstreet@linux.dev>,
	bpf@vger.kernel.org, "Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH rcu 02/11] srcu: Introduce srcu_gp_is_expedited() helper function
Date: Tue,  3 Sep 2024 09:33:09 -0700	[thread overview]
Message-ID: <20240903163318.480678-2-paulmck@kernel.org> (raw)
In-Reply-To: <26cddadd-a79b-47b1-923e-9684cd8a7ef4@paulmck-laptop>

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 <paulmck@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <bpf@vger.kernel.org>
---
 kernel/rcu/srcutree.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index 2fe0abade9c06..5b1a315f77bc6 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());
-- 
2.40.1


  parent reply	other threads:[~2024-09-03 16:33 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-09-03 16:32 [PATCH rcu 0/11] Add light-weight readers for SRCU Paul E. McKenney
2024-09-03 16:33 ` [PATCH rcu 01/11] srcu: Rename srcu_might_be_idle() to srcu_should_expedite() Paul E. McKenney
2024-09-03 16:33 ` Paul E. McKenney [this message]
2024-09-03 16:33 ` [PATCH rcu 03/11] srcu: Renaming in preparation for additional reader flavor Paul E. McKenney
2024-09-03 16:33 ` [PATCH rcu 04/11] srcu: Bit manipulation changes " Paul E. McKenney
2024-09-03 16:33 ` [PATCH rcu 05/11] srcu: Standardize srcu_data pointers to "sdp" and similar Paul E. McKenney
2024-09-03 16:33 ` [PATCH rcu 06/11] srcu: Convert srcu_data ->srcu_reader_flavor to bit field Paul E. McKenney
2024-09-03 16:33 ` [PATCH rcu 07/11] srcu: Add srcu_read_lock_lite() and srcu_read_unlock_lite() Paul E. McKenney
2024-09-03 19:45   ` Alexei Starovoitov
2024-09-03 22:10     ` Paul E. McKenney
2024-09-03 16:33 ` [PATCH rcu 08/11] rcutorture: Expand RCUTORTURE_RDR_MASK_[12] to eight bits Paul E. McKenney
2024-09-03 16:33 ` [PATCH rcu 09/11] rcutorture: Add reader_flavor parameter for SRCU readers Paul E. McKenney
2024-09-03 16:33 ` [PATCH rcu 10/11] rcutorture: Add srcu_read_lock_lite() support to rcutorture.reader_flavor Paul E. McKenney
2024-09-03 16:33 ` [PATCH rcu 11/11] refscale: Add srcu_read_lock_lite() support using "srcu-lite" Paul E. McKenney
2024-09-03 21:38 ` [PATCH rcu 0/11] Add light-weight readers for SRCU Kent Overstreet
2024-09-03 22:13   ` Paul E. McKenney
2024-09-03 23:03     ` Kent Overstreet
2024-09-04 10:54       ` Paul E. McKenney
2024-09-03 22:08 ` Andrii Nakryiko
2024-09-03 22:20   ` Paul E. McKenney
2024-10-02 19:59   ` Andrii Nakryiko
2024-10-03 16:09     ` Paul E. McKenney
2024-09-04 16:52 ` [PATCH rcu [12/11] srcu: Allow inlining of __srcu_read_{,un}lock_lite() Paul E. McKenney

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