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 = dsp_local_on_select_cpu, 60 .enqueue = dsp_local_on_enqueue, 61 .dispatch = dsp_local_on_dispatch, 62 .exit = dsp_local_on_exit, 63 .name = "dsp_local_on", 64 .timeout_ms = 1000U, 65 }; 66