xref: /linux/tools/testing/selftests/sched_ext/allowed_cpus.c (revision feacb1774bd5eac6382990d0f6d1378dc01dd78f)
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 
12 static 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 
26 static 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 
50 static 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 
70 static void cleanup(void *ctx)
71 {
72 	struct allowed_cpus *skel = ctx;
73 
74 	allowed_cpus__destroy(skel);
75 }
76 
77 struct 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 };
84 REGISTER_SCX_TEST(&allowed_cpus)
85