sched_ext: Relocate cpu_acquire/cpu_release to end of struct sched_ext_ops

cpu_acquire and cpu_release are deprecated and slated for removal. Move
their declarations to the end of struct sched_ext_ops so an upcoming
cid-form struct (sched_ext_ops_cid) can omit them entirely without
disturbing the offsets of the shared fields.

Switch the two SCX_HAS_OP() callers for these ops to direct field checks
since the relocated ops sit outside the SCX_OPI_END range covered by the
has_op bitmap.

scx_kf_allow_flags[] auto-sizes to the highest used SCX_OP_IDX, so
SCX_OP_IDX(cpu_release) moving to a higher index just enlarges the
sparse array; the lookup logic is unchanged.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Cheng-Yang Chou <yphbchou0911@gmail.com>
Reviewed-by: Changwoo Min <changwoo@igalia.com>
Reviewed-by: Andrea Righi <arighi@nvidia.com>

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 6575b52f4b9d5ffa6eeb758a8c2b02f438773ccd..6bf1418c42373443eacdb6fdd73e25391eb7b88f 100644 (file)
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -2823,7 +2823,7 @@ static int balance_one(struct rq *rq, struct task_struct *prev)
                 * core. This callback complements ->cpu_release(), which is
                 * emitted in switch_class().
                 */
-               if (SCX_HAS_OP(sch, cpu_acquire))
+               if (sch->ops.cpu_acquire)
                        SCX_CALL_OP(sch, cpu_acquire, rq, cpu, NULL);
                rq->scx.cpu_released = false;
        }
@@ -2969,7 +2969,7 @@ static void switch_class(struct rq *rq, struct task_struct *next)
         *  next time that balance_one() is invoked.
         */
        if (!rq->scx.cpu_released) {
-               if (SCX_HAS_OP(sch, cpu_release)) {
+               if (sch->ops.cpu_release) {
                        struct scx_cpu_release_args args = {
                                .reason = preempt_reason_from_class(next_class),
                                .task = next,

diff --git a/kernel/sched/ext_internal.h b/kernel/sched/ext_internal.h
index 0c55c5481fa513b133ce3e4eaf8e4c7c2cff4fc8..c6de974eaf48699bc321ad31ca517485bf75997b 100644 (file)
--- a/kernel/sched/ext_internal.h
+++ b/kernel/sched/ext_internal.h
@@ -529,28 +529,6 @@ struct sched_ext_ops {
         */
        void (*update_idle)(s32 cpu, bool idle);
 
-       /**
-        * @cpu_acquire: A CPU is becoming available to the BPF scheduler
-        * @cpu: The CPU being acquired by the BPF scheduler.
-        * @args: Acquire arguments, see the struct definition.
-        *
-        * A CPU that was previously released from the BPF scheduler is now once
-        * again under its control.
-        */
-       void (*cpu_acquire)(s32 cpu, struct scx_cpu_acquire_args *args);
-
-       /**
-        * @cpu_release: A CPU is taken away from the BPF scheduler
-        * @cpu: The CPU being released by the BPF scheduler.
-        * @args: Release arguments, see the struct definition.
-        *
-        * The specified CPU is no longer under the control of the BPF
-        * scheduler. This could be because it was preempted by a higher
-        * priority sched_class, though there may be other reasons as well. The
-        * caller should consult @args->reason to determine the cause.
-        */
-       void (*cpu_release)(s32 cpu, struct scx_cpu_release_args *args);
-
        /**
         * @init_task: Initialize a task to run in a BPF scheduler
         * @p: task to initialize for BPF scheduling
@@ -841,6 +819,38 @@ struct sched_ext_ops {
 
        /* internal use only, must be NULL */
        void __rcu *priv;
+
+       /*
+        * Deprecated callbacks. Kept at the end of the struct so the cid-form
+        * struct (sched_ext_ops_cid) can omit them without affecting the
+        * shared field offsets. Use SCX_ENQ_IMMED instead. Sitting past
+        * SCX_OPI_END means has_op doesn't cover them, so SCX_HAS_OP() cannot
+        * be used; callers must test sch->ops.cpu_acquire / cpu_release
+        * directly.
+        */
+
+       /**
+        * @cpu_acquire: A CPU is becoming available to the BPF scheduler
+        * @cpu: The CPU being acquired by the BPF scheduler.
+        * @args: Acquire arguments, see the struct definition.
+        *
+        * A CPU that was previously released from the BPF scheduler is now once
+        * again under its control. Deprecated; use SCX_ENQ_IMMED instead.
+        */
+       void (*cpu_acquire)(s32 cpu, struct scx_cpu_acquire_args *args);
+
+       /**
+        * @cpu_release: A CPU is taken away from the BPF scheduler
+        * @cpu: The CPU being released by the BPF scheduler.
+        * @args: Release arguments, see the struct definition.
+        *
+        * The specified CPU is no longer under the control of the BPF
+        * scheduler. This could be because it was preempted by a higher
+        * priority sched_class, though there may be other reasons as well. The
+        * caller should consult @args->reason to determine the cause.
+        * Deprecated; use SCX_ENQ_IMMED instead.
+        */
+       void (*cpu_release)(s32 cpu, struct scx_cpu_release_args *args);
 };
 
 enum scx_opi {