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, Christoph Hellwig <hch@infradead.org>,
"Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH v2 1/5] torture: Remove support for SRCU-lite
Date: Tue, 1 Jul 2025 17:23:26 -0700 [thread overview]
Message-ID: <20250702002330.1074433-1-paulmck@kernel.org> (raw)
In-Reply-To: <2994ade2-bd06-4ba7-bcc9-be4d0d15ea0c@paulmck-laptop>
Because SRCU-lite is being replaced by SRCU-fast, this commit removes
support for SRCU-lite from refscale.c.
Both SRCU-lite and SRCU-fast provide faster readers by dropping the
smp_mb() call from their lock and unlock primitives, but incur a pair
of added RCU grace periods during the SRCU grace period. There is a
trivial mapping from the SRCU-lite API to that of SRCU-fast, so there
should be no transition issues.
[ paulmck: Apply Christoph Hellwig feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/refscale.c | 32 +-------------------------------
1 file changed, 1 insertion(+), 31 deletions(-)
diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c
index f11a7c2af778c..f4b2cea1cce5e 100644
--- a/kernel/rcu/refscale.c
+++ b/kernel/rcu/refscale.c
@@ -246,36 +246,6 @@ static const struct ref_scale_ops srcu_fast_ops = {
.name = "srcu-fast"
};
-static void srcu_lite_ref_scale_read_section(const int nloops)
-{
- int i;
- int idx;
-
- for (i = nloops; i >= 0; i--) {
- idx = srcu_read_lock_lite(srcu_ctlp);
- srcu_read_unlock_lite(srcu_ctlp, idx);
- }
-}
-
-static void srcu_lite_ref_scale_delay_section(const int nloops, const int udl, const int ndl)
-{
- int i;
- int idx;
-
- for (i = nloops; i >= 0; i--) {
- idx = srcu_read_lock_lite(srcu_ctlp);
- un_delay(udl, ndl);
- srcu_read_unlock_lite(srcu_ctlp, idx);
- }
-}
-
-static const struct ref_scale_ops srcu_lite_ops = {
- .init = rcu_sync_scale_init,
- .readsection = srcu_lite_ref_scale_read_section,
- .delaysection = srcu_lite_ref_scale_delay_section,
- .name = "srcu-lite"
-};
-
#ifdef CONFIG_TASKS_RCU
// Definitions for RCU Tasks ref scale testing: Empty read markers.
@@ -1193,7 +1163,7 @@ ref_scale_init(void)
long i;
int firsterr = 0;
static const struct ref_scale_ops *scale_ops[] = {
- &rcu_ops, &srcu_ops, &srcu_fast_ops, &srcu_lite_ops, RCU_TRACE_OPS RCU_TASKS_OPS
+ &rcu_ops, &srcu_ops, &srcu_fast_ops, RCU_TRACE_OPS RCU_TASKS_OPS
&refcnt_ops, &rwlock_ops, &rwsem_ops, &lock_ops, &lock_irq_ops,
&acqrel_ops, &sched_clock_ops, &clock_ops, &jiffies_ops,
&typesafe_ref_ops, &typesafe_lock_ops, &typesafe_seqlock_ops,
--
2.40.1
next prev parent reply other threads:[~2025-07-02 0:23 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-24 16:13 [PATCH 0/5] Remove SRCU-lite in favor of SRCU-fast Paul E. McKenney
2025-06-24 16:13 ` [PATCH 1/5] torture: Remove support for SRCU-lite Paul E. McKenney
2025-06-25 12:05 ` Christoph Hellwig
2025-06-26 10:54 ` Paul E. McKenney
2025-06-26 11:03 ` Christoph Hellwig
2025-06-26 14:37 ` Paul E. McKenney
2025-06-24 16:13 ` [PATCH 2/5] rcutorture: Remove SRCU-lite scenarios Paul E. McKenney
2025-06-24 16:13 ` [PATCH 3/5] rcutorture: Remove support for SRCU-lite Paul E. McKenney
2025-06-24 16:13 ` [PATCH 4/5] srcu: Remove SRCU-lite implementation Paul E. McKenney
2025-06-24 16:14 ` [PATCH 5/5] checkpatch: Remove SRCU-lite deprecation Paul E. McKenney
2025-07-02 0:23 ` [PATCH v2 0/5] Remove SRCU-lite in favor of SRCU-fast Paul E. McKenney
2025-07-02 0:23 ` Paul E. McKenney [this message]
2025-07-02 0:23 ` [PATCH v2 2/5] rcutorture: Remove SRCU-lite scenarios Paul E. McKenney
2025-07-02 0:23 ` [PATCH v2 3/5] rcutorture: Remove support for SRCU-lite Paul E. McKenney
2025-07-02 0:23 ` [PATCH v2 4/5] srcu: Remove SRCU-lite implementation Paul E. McKenney
2025-07-02 0:23 ` [PATCH v2 5/5] checkpatch: Remove SRCU-lite deprecation Paul E. McKenney
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