ddsp_bogus_dsq_fail.bpf.c

 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
 9char _license[] SEC("license") = "GPL";
10
11UEI_DEFINE(uei);
12
13s32 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_dsq_insert_vtime(p, 0xcafef00d, SCX_SLICE_DFL,
24				       p->scx.dsq_vtime, 0);
25		return cpu;
26	}
27
28	return prev_cpu;
29}
30
31void BPF_STRUCT_OPS(ddsp_bogus_dsq_fail_exit, struct scx_exit_info *ei)
32{
33	UEI_RECORD(uei, ei);
34}
35
36SEC(".struct_ops.link")
37struct 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};