1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
|
/* SPDX-License-Identifier: GPL-2.0 */
/*
* A scheduler that validates that enqueue flags are properly stored and
* applied at dispatch time when a task is directly dispatched from
* ops.select_cpu(). We validate this by using scx_bpf_dispatch_vtime(), and
* making the test a very basic vtime scheduler.
*
* Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
* Copyright (c) 2024 David Vernet <dvernet@meta.com>
* Copyright (c) 2024 Tejun Heo <tj@kernel.org>
*/
#include <scx/common.bpf.h>
char _license[] SEC("license") = "GPL";
volatile bool consumed;
static u64 vtime_now;
#define VTIME_DSQ 0
static inline bool vtime_before(u64 a, u64 b)
{
return (s64)(a - b) < 0;
}
static inline u64 task_vtime(const struct task_struct *p)
{
u64 vtime = p->scx.dsq_vtime;
if (vtime_before(vtime, vtime_now - SCX_SLICE_DFL))
return vtime_now - SCX_SLICE_DFL;
else
return vtime;
}
s32 BPF_STRUCT_OPS(select_cpu_vtime_select_cpu, struct task_struct *p,
s32 prev_cpu, u64 wake_flags)
{
s32 cpu;
cpu = scx_bpf_pick_idle_cpu(p->cpus_ptr, 0);
if (cpu >= 0)
goto ddsp;
cpu = prev_cpu;
scx_bpf_test_and_clear_cpu_idle(cpu);
ddsp:
scx_bpf_dispatch_vtime(p, VTIME_DSQ, SCX_SLICE_DFL, task_vtime(p), 0);
return cpu;
}
void BPF_STRUCT_OPS(select_cpu_vtime_dispatch, s32 cpu, struct task_struct *p)
{
if (scx_bpf_consume(VTIME_DSQ))
consumed = true;
}
void BPF_STRUCT_OPS(select_cpu_vtime_running, struct task_struct *p)
{
if (vtime_before(vtime_now, p->scx.dsq_vtime))
vtime_now = p->scx.dsq_vtime;
}
void BPF_STRUCT_OPS(select_cpu_vtime_stopping, struct task_struct *p,
bool runnable)
{
p->scx.dsq_vtime += (SCX_SLICE_DFL - p->scx.slice) * 100 / p->scx.weight;
}
void BPF_STRUCT_OPS(select_cpu_vtime_enable, struct task_struct *p)
{
p->scx.dsq_vtime = vtime_now;
}
s32 BPF_STRUCT_OPS_SLEEPABLE(select_cpu_vtime_init)
{
return scx_bpf_create_dsq(VTIME_DSQ, -1);
}
SEC(".struct_ops.link")
struct sched_ext_ops select_cpu_vtime_ops = {
.select_cpu = (void *) select_cpu_vtime_select_cpu,
.dispatch = (void *) select_cpu_vtime_dispatch,
.running = (void *) select_cpu_vtime_running,
.stopping = (void *) select_cpu_vtime_stopping,
.enable = (void *) select_cpu_vtime_enable,
.init = (void *) select_cpu_vtime_init,
.name = "select_cpu_vtime",
.timeout_ms = 1000U,
};
|
