[PATCH 01/17] sched_ext: Add ext_types.h for early subsystem-wide defs

Tejun Heo
2026-04-24T17:27:24Z

Introduce kernel/sched/ext_types.h as the early-def header for the
sched_ext compilation unit. Included from kernel/sched/build_policy.c
before ext_internal.h so every later header and source in the unit
sees its content without re-inclusion. Later patches add their types
here (struct scx_cid_topo, scx_cmask, scx_cid_shard, etc.) so the
subsystem has one place to stash types shared across the TU.

Move enum scx_consts (SCX_DSP_DFL_MAX_BATCH, SCX_WATCHDOG_MAX_TIMEOUT,
SCX_SUB_MAX_DEPTH, etc.) here as the initial content. Ops-facing
content stays in ext_internal.h.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/sched/build_policy.c | 1 +
kernel/sched/ext_internal.h | 32 ---------------------------
kernel/sched/ext_types.h | 43 +++++++++++++++++++++++++++++++++++++
3 files changed, 44 insertions(+), 32 deletions(-)
create mode 100644 kernel/sched/ext_types.h

diff --git a/kernel/sched/build_policy.c b/kernel/sched/build_policy.c
index 755883faf751..180ade38625e 100644
--- a/kernel/sched/build_policy.c
+++ b/kernel/sched/build_policy.c
@@ -58,6 +58,7 @@
#include "deadline.c"

#ifdef CONFIG_SCHED_CLASS_EXT
+# include "ext_types.h"
# include "ext_internal.h"
# include "ext.c"
# include "ext_idle.c"
diff --git a/kernel/sched/ext_internal.h b/kernel/sched/ext_internal.h
index 4a7ffc7f55d2..c35098668fb1 100644
--- a/kernel/sched/ext_internal.h
+++ b/kernel/sched/ext_internal.h
@@ -8,38 +8,6 @@
#define SCX_OP_IDX(op) (offsetof(struct sched_ext_ops, op) / sizeof(void (*)(void)))
#define SCX_MOFF_IDX(moff) ((moff) / sizeof(void (*)(void)))

-enum scx_consts {
- SCX_DSP_DFL_MAX_BATCH = 32,
- SCX_DSP_MAX_LOOPS = 32,
- SCX_WATCHDOG_MAX_TIMEOUT = 30 * HZ,
-
- /* per-CPU chunk size for p->scx.tid allocation, see scx_alloc_tid() */
- SCX_TID_CHUNK = 1024,
-
- SCX_EXIT_BT_LEN = 64,
- SCX_EXIT_MSG_LEN = 1024,
- SCX_EXIT_DUMP_DFL_LEN = 32768,
-
- SCX_CPUPERF_ONE = SCHED_CAPACITY_SCALE,
-
- /*
- * Iterating all tasks may take a while. Periodically drop
- * scx_tasks_lock to avoid causing e.g. CSD and RCU stalls.
- */
- SCX_TASK_ITER_BATCH = 32,
-
- SCX_BYPASS_HOST_NTH = 2,
-
- SCX_BYPASS_LB_DFL_INTV_US = 500 * USEC_PER_MSEC,
- SCX_BYPASS_LB_DONOR_PCT = 125,
- SCX_BYPASS_LB_MIN_DELTA_DIV = 4,
- SCX_BYPASS_LB_BATCH = 256,
-
- SCX_REENQ_LOCAL_MAX_REPEAT = 256,
-
- SCX_SUB_MAX_DEPTH = 4,
-};
-
enum scx_exit_kind {
SCX_EXIT_NONE,
SCX_EXIT_DONE,
diff --git a/kernel/sched/ext_types.h b/kernel/sched/ext_types.h
new file mode 100644
index 000000000000..19299ec3920e
--- /dev/null
+++ b/kernel/sched/ext_types.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Early sched_ext type definitions.
+ *
+ * Copyright (c) 2026 Meta Platforms, Inc. and affiliates.
+ * Copyright (c) 2026 Tejun Heo <tj@kernel.org>
+ */
+#ifndef _KERNEL_SCHED_EXT_TYPES_H
+#define _KERNEL_SCHED_EXT_TYPES_H
+
+enum scx_consts {
+ SCX_DSP_DFL_MAX_BATCH = 32,
+ SCX_DSP_MAX_LOOPS = 32,
+ SCX_WATCHDOG_MAX_TIMEOUT = 30 * HZ,
+
+ /* per-CPU chunk size for p->scx.tid allocation, see scx_alloc_tid() */
+ SCX_TID_CHUNK = 1024,
+
+ SCX_EXIT_BT_LEN = 64,
+ SCX_EXIT_MSG_LEN = 1024,
+ SCX_EXIT_DUMP_DFL_LEN = 32768,
+
+ SCX_CPUPERF_ONE = SCHED_CAPACITY_SCALE,
+
+ /*
+ * Iterating all tasks may take a while. Periodically drop
+ * scx_tasks_lock to avoid causing e.g. CSD and RCU stalls.
+ */
+ SCX_TASK_ITER_BATCH = 32,
+
+ SCX_BYPASS_HOST_NTH = 2,
+
+ SCX_BYPASS_LB_DFL_INTV_US = 500 * USEC_PER_MSEC,
+ SCX_BYPASS_LB_DONOR_PCT = 125,
+ SCX_BYPASS_LB_MIN_DELTA_DIV = 4,
+ SCX_BYPASS_LB_BATCH = 256,
+
+ SCX_REENQ_LOCAL_MAX_REPEAT = 256,
+
+ SCX_SUB_MAX_DEPTH = 4,
+};
+
+#endif /* _KERNEL_SCHED_EXT_TYPES_H */
--
2.53.0