allowed_cpus.c

 1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Copyright (c) 2025 Andrea Righi <arighi@nvidia.com>
 4 */
 5#include <bpf/bpf.h>
 6#include <scx/common.h>
 7#include <sys/wait.h>
 8#include <unistd.h>
 9#include "allowed_cpus.bpf.skel.h"
10#include "scx_test.h"
11
12static enum scx_test_status setup(void **ctx)
13{
14	struct allowed_cpus *skel;
15
16	skel = allowed_cpus__open();
17	SCX_FAIL_IF(!skel, "Failed to open");
18	SCX_ENUM_INIT(skel);
19	SCX_FAIL_IF(allowed_cpus__load(skel), "Failed to load skel");
20
21	*ctx = skel;
22
23	return SCX_TEST_PASS;
24}
25
26static int test_select_cpu_from_user(const struct allowed_cpus *skel)
27{
28	int fd, ret;
29	__u64 args[1];
30
31	LIBBPF_OPTS(bpf_test_run_opts, attr,
32		.ctx_in = args,
33		.ctx_size_in = sizeof(args),
34	);
35
36	args[0] = getpid();
37	fd = bpf_program__fd(skel->progs.select_cpu_from_user);
38	if (fd < 0)
39		return fd;
40
41	ret = bpf_prog_test_run_opts(fd, &attr);
42	if (ret < 0)
43		return ret;
44
45	fprintf(stderr, "%s: CPU %d\n", __func__, attr.retval);
46
47	return 0;
48}
49
50static enum scx_test_status run(void *ctx)
51{
52	struct allowed_cpus *skel = ctx;
53	struct bpf_link *link;
54
55	link = bpf_map__attach_struct_ops(skel->maps.allowed_cpus_ops);
56	SCX_FAIL_IF(!link, "Failed to attach scheduler");
57
58	/* Pick an idle CPU from user-space */
59	SCX_FAIL_IF(test_select_cpu_from_user(skel), "Failed to pick idle CPU");
60
61	/* Just sleeping is fine, plenty of scheduling events happening */
62	sleep(1);
63
64	SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_NONE));
65	bpf_link__destroy(link);
66
67	return SCX_TEST_PASS;
68}
69
70static void cleanup(void *ctx)
71{
72	struct allowed_cpus *skel = ctx;
73
74	allowed_cpus__destroy(skel);
75}
76
77struct scx_test allowed_cpus = {
78	.name = "allowed_cpus",
79	.description = "Verify scx_bpf_select_cpu_and()",
80	.setup = setup,
81	.run = run,
82	.cleanup = cleanup,
83};
84REGISTER_SCX_TEST(&allowed_cpus)