[PATCH bpf-next v9 0/5] Parameterize task iterators.

Kui-Feng Lee
2022-08-31T02:38:22Z

Allow creating an iterator that loops through resources of one task/thread.

People could only create iterators to loop through all resources of
files, vma, and tasks in the system, even though they were interested in only the
resources of a specific task or process. Passing the additional
parameters, people can now create an iterator to go through all
resources or only the resources of a task.

Major Changes:

- Add new parameters in bpf_iter_link_info to indicate to go through
all tasks or to go through a specific task.

- Change the implementations of BPF iterators of vma, files, and
tasks to allow going through only the resources of a specific task.

- Provide the arguments of parameterized task iterators in
bpf_link_info.

Differences from v8:

- Fix uninitialized variable.

- Avoid redundant work of getting task from pid.

- Change format string to use %u instead of %d.

- Use the value of page_shift to compute correct offset in
bpf_iter_vm_offset.c.

Differences from v7:

- Travel the tasks of a process through task_group linked list
instead of traveling through the whole namespace.

Differences from v6:

- Add part 5 to make bpftool show the value of parameters.

- Change of wording of show_fdinfo() to show pid or tid instead of
always pid.

- Simplify error handling and naming of test cases.

Differences from v5:

- Use user-space tid/pid terminologies in bpf_iter_link_info and
bpf_link_info.

- Fix reference count

- Merge all variants to one 'u32 pid' in internal structs.
(bpf_iter_aux_info and bpf_iter_seq_task_common)

- Compare the result of get_uprobe_offset() with the implementation
with the vma iterators.

- Implement show_fdinfo.

Differences from v4:

- Remove 'type' from bpf_iter_link_info and bpf_link_info.

v8: https://lore.kernel.org/bpf/20220829192317.486946-1-kuifeng@fb.com/
v7: https://lore.kernel.org/bpf/20220826003712.2810158-1-kuifeng@fb.com/
v6: https://lore.kernel.org/bpf/20220819220927.3409575-1-kuifeng@fb.com/
v5: https://lore.kernel.org/bpf/20220811001654.1316689-1-kuifeng@fb.com/
v4: https://lore.kernel.org/bpf/20220809195429.1043220-1-kuifeng@fb.com/
v3: https://lore.kernel.org/bpf/20220809063501.667610-1-kuifeng@fb.com/
v2: https://lore.kernel.org/bpf/20220801232649.2306614-1-kuifeng@fb.com/
v1: https://lore.kernel.org/bpf/20220726051713.840431-1-kuifeng@fb.com/

Kui-Feng Lee (5):
bpf: Parameterize task iterators.
bpf: Handle bpf_link_info for the parameterized task BPF iterators.
bpf: Handle show_fdinfo for the parameterized task BPF iterators
selftests/bpf: Test parameterized task BPF iterators.
bpftool: Show parameters of BPF task iterators.

include/linux/bpf.h | 25 ++
include/uapi/linux/bpf.h | 10 +
kernel/bpf/task_iter.c | 227 ++++++++++++--
tools/bpf/bpftool/link.c | 19 ++
tools/include/uapi/linux/bpf.h | 10 +
.../selftests/bpf/prog_tests/bpf_iter.c | 282 ++++++++++++++++--
.../selftests/bpf/prog_tests/btf_dump.c | 2 +-
.../selftests/bpf/progs/bpf_iter_task.c | 9 +
.../selftests/bpf/progs/bpf_iter_task_file.c | 9 +-
.../selftests/bpf/progs/bpf_iter_task_vma.c | 7 +-
.../selftests/bpf/progs/bpf_iter_vma_offset.c | 37 +++
11 files changed, 591 insertions(+), 46 deletions(-)
create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_vma_offset.c

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2.30.2