[PATCH 06/10] sched_ext: Introduce SCX_OPS_NODE_BUILTIN_IDLE

Andrea Righi
2024-12-20T15:41:44Z

Add the new scheduler flag SCX_OPS_NODE_BUILTIN_IDLE, which allows each
scx scheduler to select between using a global flat idle cpumask or
multiple per-node cpumasks.

Signed-off-by: Andrea Righi <arighi@nvidia.com>
---
kernel/sched/ext.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 769e43fdea1e..148ec04d4a0a 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -124,6 +124,12 @@ enum scx_ops_flags {
*/
SCX_OPS_SWITCH_PARTIAL = 1LLU << 3,

+ /*
+ * If set, enable per-node idle cpumasks. If clear, use a single global
+ * flat idle cpumask.
+ */
+ SCX_OPS_BUILTIN_IDLE_PER_NODE = 1LLU << 4,
+
/*
* CPU cgroup support flags
*/
@@ -133,6 +139,7 @@ enum scx_ops_flags {
SCX_OPS_ENQ_LAST |
SCX_OPS_ENQ_EXITING |
SCX_OPS_SWITCH_PARTIAL |
+ SCX_OPS_BUILTIN_IDLE_PER_NODE |
SCX_OPS_HAS_CGROUP_WEIGHT,
};

@@ -4974,6 +4981,16 @@ static int validate_ops(const struct sched_ext_ops *ops)
return -EINVAL;
}

+ /*
+ * SCX_OPS_BUILTIN_IDLE_PER_NODE requires built-in CPU idle
+ * selection policy to be enabled.
+ */
+ if ((ops->flags & SCX_OPS_BUILTIN_IDLE_PER_NODE) &&
+ (ops->update_idle && !(ops->flags & SCX_OPS_KEEP_BUILTIN_IDLE))) {
+ scx_ops_error("SCX_OPS_BUILTIN_IDLE_PER_NODE requires CPU idle selection enabled");
+ return -EINVAL;
+ }
+
return 0;
}

--
2.47.1