// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES
 *
 * Exercise tick dependency transitions between infinite and finite slices.
 */
#include <scx/common.bpf.h>

char _license[] SEC("license") = "GPL";

const volatile s32 test_cpu;
bool finite_phase;
u64 nr_inf_running;
u64 nr_finite_running;
u64 nr_finite_ticks;

UEI_DEFINE(uei);

s32 BPF_STRUCT_OPS(nohz_tick_select_cpu, struct task_struct *p, s32 prev_cpu,
                   u64 wake_flags)
{
        return prev_cpu;
}

void BPF_STRUCT_OPS(nohz_tick_enqueue, struct task_struct *p, u64 enq_flags)
{
        u64 slice = finite_phase ? 1000000ULL : SCX_SLICE_INF;

        scx_bpf_dsq_insert(p, SCX_DSQ_GLOBAL, slice, enq_flags);
        if (enq_flags & SCX_ENQ_LAST)
                scx_bpf_kick_cpu(test_cpu, SCX_KICK_IDLE);
}

void BPF_STRUCT_OPS(nohz_tick_running, struct task_struct *p)
{
        if (bpf_get_smp_processor_id() != test_cpu)
                return;

        if (finite_phase)
                __sync_fetch_and_add(&nr_finite_running, 1);
        else
                __sync_fetch_and_add(&nr_inf_running, 1);
}

void BPF_STRUCT_OPS(nohz_tick_tick, struct task_struct *p)
{
        if (bpf_get_smp_processor_id() == test_cpu && finite_phase)
                __sync_fetch_and_add(&nr_finite_ticks, 1);
}

void BPF_STRUCT_OPS(nohz_tick_exit, struct scx_exit_info *ei)
{
        UEI_RECORD(uei, ei);
}

SEC(".struct_ops.link")
struct sched_ext_ops nohz_tick_ops = {
        .select_cpu             = (void *)nohz_tick_select_cpu,
        .enqueue                = (void *)nohz_tick_enqueue,
        .running                = (void *)nohz_tick_running,
        .tick                   = (void *)nohz_tick_tick,
        .exit                   = (void *)nohz_tick_exit,
        .name                   = "nohz_tick",
        .timeout_ms             = 1000U,
};