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 */
6 #include <scx/common.bpf.h>
7
8 char _license[] SEC("license") = "GPL";
9 const volatile s32 nr_cpus;
10
11 UEI_DEFINE(uei);
12
13 struct {
14 __uint(type, BPF_MAP_TYPE_QUEUE);
15 __uint(max_entries, 8192);
16 __type(value, s32);
17 } queue SEC(".maps");
18
19 s32 BPF_STRUCT_OPS(dsp_local_on_select_cpu, struct task_struct *p,
20 s32 prev_cpu, u64 wake_flags)
21 {
22 return prev_cpu;
23 }
24
25 void BPF_STRUCT_OPS(dsp_local_on_enqueue, struct task_struct *p,
26 u64 enq_flags)
27 {
28 s32 pid = p->pid;
29
30 if (bpf_map_push_elem(&queue, &pid, 0))
31 scx_bpf_error("Failed to enqueue %s[%d]", p->comm, p->pid);
32 }
33
34 void BPF_STRUCT_OPS(dsp_local_on_dispatch, s32 cpu, struct task_struct *prev)
35 {
36 s32 pid, target;
37 struct task_struct *p;
38
39 if (bpf_map_pop_elem(&queue, &pid))
40 return;
41
42 p = bpf_task_from_pid(pid);
43 if (!p)
44 return;
45
46 target = bpf_get_prandom_u32() % nr_cpus;
47
48 scx_bpf_dispatch(p, SCX_DSQ_LOCAL_ON | target, SCX_SLICE_DFL, 0);
49 bpf_task_release(p);
50 }
51
52 void BPF_STRUCT_OPS(dsp_local_on_exit, struct scx_exit_info *ei)
53 {
54 UEI_RECORD(uei, ei);
55 }
56
57 SEC(".struct_ops.link")
58 struct sched_ext_ops dsp_local_on_ops = {
59 .select_cpu = (void *) dsp_local_on_select_cpu,
60 .enqueue = (void *) dsp_local_on_enqueue,
61 .dispatch = (void *) dsp_local_on_dispatch,
62 .exit = (void *) dsp_local_on_exit,
63 .name = "dsp_local_on",
64 .timeout_ms = 1000U,
65 };
66
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