1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
4 * Copyright (c) 2023 David Vernet <dvernet@meta.com>
5 * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
6 */
7
8 #include <scx/common.bpf.h>
9
10 char _license[] SEC("license") = "GPL";
11
12 /* Manually specify the signature until the kfunc is added to the scx repo. */
13 s32 scx_bpf_select_cpu_dfl(struct task_struct *p, s32 prev_cpu, u64 wake_flags,
14 bool *found) __ksym;
15
BPF_STRUCT_OPS(enq_select_cpu_fails_select_cpu,struct task_struct * p,s32 prev_cpu,u64 wake_flags)16 s32 BPF_STRUCT_OPS(enq_select_cpu_fails_select_cpu, struct task_struct *p,
17 s32 prev_cpu, u64 wake_flags)
18 {
19 return prev_cpu;
20 }
21
BPF_STRUCT_OPS(enq_select_cpu_fails_enqueue,struct task_struct * p,u64 enq_flags)22 void BPF_STRUCT_OPS(enq_select_cpu_fails_enqueue, struct task_struct *p,
23 u64 enq_flags)
24 {
25 /*
26 * Need to initialize the variable or the verifier will fail to load.
27 * Improving these semantics is actively being worked on.
28 */
29 bool found = false;
30
31 /* Can only call from ops.select_cpu() */
32 scx_bpf_select_cpu_dfl(p, 0, 0, &found);
33
34 scx_bpf_dispatch(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, enq_flags);
35 }
36
37 SEC(".struct_ops.link")
38 struct sched_ext_ops enq_select_cpu_fails_ops = {
39 .select_cpu = (void *) enq_select_cpu_fails_select_cpu,
40 .enqueue = (void *) enq_select_cpu_fails_enqueue,
41 .name = "enq_select_cpu_fails",
42 .timeout_ms = 1000U,
43 };
44