xref: /linux/tools/testing/selftests/sched_ext/ddsp_bogus_dsq_fail.bpf.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
4  * Copyright (c) 2024 David Vernet <dvernet@meta.com>
5  * Copyright (c) 2024 Tejun Heo <tj@kernel.org>
6  */
7 #include <scx/common.bpf.h>
8 
9 char _license[] SEC("license") = "GPL";
10 
11 UEI_DEFINE(uei);
12 
13 s32 BPF_STRUCT_OPS(ddsp_bogus_dsq_fail_select_cpu, struct task_struct *p,
14 		   s32 prev_cpu, u64 wake_flags)
15 {
16 	s32 cpu = scx_bpf_pick_idle_cpu(p->cpus_ptr, 0);
17 
18 	if (cpu >= 0) {
19 		/*
20 		 * If we dispatch to a bogus DSQ that will fall back to the
21 		 * builtin global DSQ, we fail gracefully.
22 		 */
23 		scx_bpf_dispatch_vtime(p, 0xcafef00d, SCX_SLICE_DFL,
24 				       p->scx.dsq_vtime, 0);
25 		return cpu;
26 	}
27 
28 	return prev_cpu;
29 }
30 
31 void BPF_STRUCT_OPS(ddsp_bogus_dsq_fail_exit, struct scx_exit_info *ei)
32 {
33 	UEI_RECORD(uei, ei);
34 }
35 
36 SEC(".struct_ops.link")
37 struct sched_ext_ops ddsp_bogus_dsq_fail_ops = {
38 	.select_cpu		= (void *) ddsp_bogus_dsq_fail_select_cpu,
39 	.exit			= (void *) ddsp_bogus_dsq_fail_exit,
40 	.name			= "ddsp_bogus_dsq_fail",
41 	.timeout_ms		= 1000U,
42 };
43