On 24/03/18 10:58AM, Jiri Olsa wrote:
On Sat, Mar 16, 2024 at 10:22:41AM -0600, Jose Fernandez wrote:
SNIP
+void test_task_get_cgroup(void) +{
- struct test_task_get_cgroup *skel;
- int err, fd;
- pid_t pid;
- __u64 cgroup_id, expected_cgroup_id;
- const struct timespec req = {
.tv_sec = 1,.tv_nsec = 0,- };
- fd = test__join_cgroup(TEST_CGROUP);
- if (!ASSERT_OK(fd < 0, "test_join_cgroup_TEST_CGROUP"))
return;- skel = test_task_get_cgroup__open();
- if (!ASSERT_OK_PTR(skel, "test_task_get_cgroup__open"))
goto cleanup;- err = test_task_get_cgroup__load(skel);
- if (!ASSERT_OK(err, "test_task_get_cgroup__load"))
goto cleanup;nit, you could call test_task_get_cgroup__open_and_load
I'll rename.
- err = test_task_get_cgroup__attach(skel);
- if (!ASSERT_OK(err, "test_task_get_cgroup__attach"))
goto cleanup;- pid = getpid();
- expected_cgroup_id = get_cgroup_id(TEST_CGROUP);
- if (!ASSERT_GT(expected_cgroup_id, 0, "get_cgroup_id"))
goto cleanup;- /* Trigger nanosleep to enter the sched_switch tracepoint */
- /* The previous task should be this process */
- syscall(__NR_nanosleep, &req, NULL);
would smaller sleep do? also we have our own usleep (in test_progs.c) that calls nanosleep
Yes a smaller sleep should be fine. I'll reduce the sleep and use the usleep helper.
- err = bpf_map_lookup_elem(bpf_map__fd(skel->maps.pid_to_cgid_map), &pid,
&cgroup_id);- if (!ASSERT_OK(err, "bpf_map_lookup_elem"))
goto cleanup;- ASSERT_EQ(cgroup_id, expected_cgroup_id, "cgroup_id");
+cleanup:
- test_task_get_cgroup__destroy(skel);
- close(fd);
+} diff --git a/tools/testing/selftests/bpf/progs/test_task_get_cgroup.c b/tools/testing/selftests/bpf/progs/test_task_get_cgroup.c new file mode 100644 index 000000000000..580f8f0657d5 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_task_get_cgroup.c @@ -0,0 +1,37 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright 2024 Netflix, Inc.
+#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h>
+struct cgroup *bpf_task_get_cgroup(struct task_struct *task) __ksym; +void bpf_cgroup_release(struct cgroup *cgrp) __ksym;
+struct {
- __uint(type, BPF_MAP_TYPE_HASH);
- __uint(max_entries, 4096);
- __type(key, __u32);
- __type(value, __u64);
+} pid_to_cgid_map SEC(".maps");
+SEC("tp_btf/sched_switch") +int BPF_PROG(sched_switch, bool preempt, struct task_struct *prev,
struct task_struct *next)+{
- struct cgroup *cgrp;
- u64 cgroup_id;
- u32 pid;
could you filter for your pid in here like we do in other places, (eg in progs/kprobe_multi.c)
in which case you won't need hash map, but just a single value to store the cgroup id to
jirka
I'll apply this suggestion as well and include it in V3. Thanks for the feedback.
- cgrp = bpf_task_get_cgroup(prev);
- if (cgrp == NULL)
return 0;- cgroup_id = cgrp->kn->id;
- pid = prev->pid;
- bpf_map_update_elem(&pid_to_cgid_map, &pid, &cgroup_id, BPF_ANY);
- bpf_cgroup_release(cgrp);
- return 0;
+}
+char _license[] SEC("license") = "GPL";
2.40.1