| Message ID | 20240316162241.628855-2-josef@netflix.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [V2,bpf-next,1/2] bpf: add bpf_task_get_cgroup kfunc | expand |
On 2024-03-16 at 21:52:41, Jose Fernandez (josef@netflix.com) wrote: > This patch adds a selftest for the `bpf_task_get_cgroup` kfunc. The test > focuses on the use case of obtaining the cgroup ID of the previous task > in a `sched_switch` tracepoint. > > The selftest involves creating a test cgroup, attaching a BPF program > that utilizes the `bpf_task_get_cgroup` during a `sched_switch` > tracepoint, and validating that the obtained cgroup ID for the previous > task matches the expected cgroup ID. > > Signed-off-by: Jose Fernandez <josef@netflix.com> > Reviewed-by: Tycho Andersen <tycho@tycho.pizza> > --- > V1 -> V2: Refactor test to work with a cgroup pointer instead of the ID > > .../bpf/prog_tests/task_get_cgroup.c | 58 +++++++++++++++++++ > .../bpf/progs/test_task_get_cgroup.c | 37 ++++++++++++ > 2 files changed, 95 insertions(+) > create mode 100644 tools/testing/selftests/bpf/prog_tests/task_get_cgroup.c > create mode 100644 tools/testing/selftests/bpf/progs/test_task_get_cgroup.c > > diff --git a/tools/testing/selftests/bpf/prog_tests/task_get_cgroup.c b/tools/testing/selftests/bpf/prog_tests/task_get_cgroup.c > new file mode 100644 > index 000000000000..67ed65d0c461 > --- /dev/null > +++ b/tools/testing/selftests/bpf/prog_tests/task_get_cgroup.c > @@ -0,0 +1,58 @@ > +// SPDX-License-Identifier: GPL-2.0 > +// Copyright 2024 Netflix, Inc. > + > +#include <test_progs.h> > +#include <cgroup_helpers.h> > +#include "test_task_get_cgroup.skel.h" > +#include <unistd.h> > + > +#define TEST_CGROUP "/test-task-get-cgroup/" > + > +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, > + }; Reverse Xmas tree. > + > + 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; > + > + 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); > + > + 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; > + > + 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 >
On Sun, Mar 17, 2024 at 8:10 PM Ratheesh Kannoth <rkannoth@marvell.com> wrote: > > On 2024-03-16 at 21:52:41, Jose Fernandez (josef@netflix.com) wrote: > > This patch adds a selftest for the `bpf_task_get_cgroup` kfunc. The test > > focuses on the use case of obtaining the cgroup ID of the previous task > > in a `sched_switch` tracepoint. > > > > The selftest involves creating a test cgroup, attaching a BPF program > > that utilizes the `bpf_task_get_cgroup` during a `sched_switch` > > tracepoint, and validating that the obtained cgroup ID for the previous > > task matches the expected cgroup ID. > > > > Signed-off-by: Jose Fernandez <josef@netflix.com> > > Reviewed-by: Tycho Andersen <tycho@tycho.pizza> > > --- > > V1 -> V2: Refactor test to work with a cgroup pointer instead of the ID > > > > .../bpf/prog_tests/task_get_cgroup.c | 58 +++++++++++++++++++ > > .../bpf/progs/test_task_get_cgroup.c | 37 ++++++++++++ > > 2 files changed, 95 insertions(+) > > create mode 100644 tools/testing/selftests/bpf/prog_tests/task_get_cgroup.c > > create mode 100644 tools/testing/selftests/bpf/progs/test_task_get_cgroup.c > > > > diff --git a/tools/testing/selftests/bpf/prog_tests/task_get_cgroup.c b/tools/testing/selftests/bpf/prog_tests/task_get_cgroup.c > > new file mode 100644 > > index 000000000000..67ed65d0c461 > > --- /dev/null > > +++ b/tools/testing/selftests/bpf/prog_tests/task_get_cgroup.c > > @@ -0,0 +1,58 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +// Copyright 2024 Netflix, Inc. > > + > > +#include <test_progs.h> > > +#include <cgroup_helpers.h> > > +#include "test_task_get_cgroup.skel.h" > > +#include <unistd.h> > > + > > +#define TEST_CGROUP "/test-task-get-cgroup/" > > + > > +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, > > + }; > Reverse Xmas tree. NO. We don't do it in bpf trees.
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 > + > + 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 > + > + 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 > + 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 >
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 > >
diff --git a/tools/testing/selftests/bpf/prog_tests/task_get_cgroup.c b/tools/testing/selftests/bpf/prog_tests/task_get_cgroup.c new file mode 100644 index 000000000000..67ed65d0c461 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/task_get_cgroup.c @@ -0,0 +1,58 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright 2024 Netflix, Inc. + +#include <test_progs.h> +#include <cgroup_helpers.h> +#include "test_task_get_cgroup.skel.h" +#include <unistd.h> + +#define TEST_CGROUP "/test-task-get-cgroup/" + +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; + + 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); + + 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; + + 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";