Re: [PATCH] rcuscale: add srcu_atomic scale type

[Bradley Morgan]

On 27 September 2026 11:03:59 BST, Kunwu Chan <kunwu.chan@xxxxxxxxx> wrote:
>Add support for scaling atomic SRCU grace periods using
>srcu_read_lock_atomic()/srcu_read_unlock_atomic() and
>synchronize_srcu_atomic().
>

Ummm. Ok then!

Reviewed-by: Bradley Morgan <brads@xxxxxxxxxxxxxx>


>Signed-off-by: Kunwu Chan <kunwu.chan@xxxxxxxxx>
>---
> kernel/rcu/rcuscale.c | 47 ++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 46 insertions(+), 1 deletion(-)
>
>diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c
>index 5aca31c3c01d..86f1a912ebee 100644
>--- a/kernel/rcu/rcuscale.c
>+++ b/kernel/rcu/rcuscale.c
>@@ -264,6 +264,51 @@ static struct rcu_scale_ops srcu_ops = {
> 	.name		= "srcu"
> };
> 
>+static struct srcu_struct srcu_atomic_ctlp;
>+
>+static int srcu_scale_atomic_read_lock(void)
>+{
>+	return srcu_read_lock_atomic(&srcu_atomic_ctlp);
>+}
>+
>+static void srcu_scale_atomic_read_unlock(int idx)
>+{
>+	srcu_read_unlock_atomic(&srcu_atomic_ctlp, idx);
>+}
>+
>+static void srcu_scale_atomic_synchronize(void)
>+{
>+	synchronize_srcu_atomic(&srcu_atomic_ctlp);
>+}
>+
>+static void srcu_atomic_scale_init(void)
>+{
>+	init_srcu_struct_atomic(&srcu_atomic_ctlp);
>+}
>+
>+static void srcu_atomic_scale_cleanup(void)
>+{
>+	cleanup_srcu_struct(&srcu_atomic_ctlp);
>+}
>+
>+static unsigned long srcu_atomic_scale_completed(void)
>+{
>+	return srcu_batches_completed(&srcu_atomic_ctlp);
>+}
>+
>+static struct rcu_scale_ops srcu_atomic_ops = {
>+	.ptype		= SRCU_FLAVOR,
>+	.init		= srcu_atomic_scale_init,
>+	.cleanup	= srcu_atomic_scale_cleanup,
>+	.readlock	= srcu_scale_atomic_read_lock,
>+	.readunlock	= srcu_scale_atomic_read_unlock,
>+	.get_gp_seq	= srcu_atomic_scale_completed,
>+	.gp_diff	= rcu_seq_diff,
>+	.exp_completed	= srcu_atomic_scale_completed,
>+	.sync		= srcu_scale_atomic_synchronize,
>+	.name		= "srcu_atomic"
>+};
>+
> static struct srcu_struct srcud;
> 
> static void srcu_sync_scale_init(void)
>@@ -1176,7 +1221,7 @@ rcu_scale_init(void)
> 	long i;
> 	long j;
> 	static struct rcu_scale_ops *scale_ops[] = {
>-		&rcu_ops, &srcu_ops, &srcud_ops,
>+		&rcu_ops, &srcu_ops, &srcu_atomic_ops, &srcud_ops,
> 		TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS
> 		HAZPTR_SCALE_OPS
> 	};
>

--- Thanks!
"I'm not a very positive person" - Linus torvalds