[bpf-next,v11,0/5] Parameterize task iterators.

Message

Kui-Feng Lee Sept. 26, 2022, 6:49 p.m. UTC

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 v10:

 - Check pid_alive() to avoid potential errors.

Differences from v9:

  - Fix the boundary check of computing page_shift.

  - Rewording the reason of checking and returning the same task.

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.

v10: https://lore.kernel.org/all/[e-mail]/
v9: https://lore.kernel.org/bpf/[e-mail]/
v8: https://lore.kernel.org/bpf/[e-mail]/
v7: https://lore.kernel.org/bpf/[e-mail]/
v6: https://lore.kernel.org/bpf/[e-mail]/
v5: https://lore.kernel.org/bpf/[e-mail]/
v4: https://lore.kernel.org/bpf/[e-mail]/
v3: https://lore.kernel.org/bpf/[e-mail]/
v2: https://lore.kernel.org/bpf/[e-mail]/
v1: https://lore.kernel.org/bpf/[e-mail]/

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                        | 228 ++++++++++++--
 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, 592 insertions(+), 46 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_vma_offset.c

Comments

Martin KaFai Lau Sept. 27, 2022, 7:33 p.m. UTC | #1

On 9/26/22 11:49 AM, Kui-Feng Lee wrote:
> 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.

Acked-by: Martin KaFai Lau <[e-mail]>

[e-mail] Sept. 28, 2022, 11:40 p.m. UTC | #2

Hello:

This series was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <[e-mail]>:

On Mon, 26 Sep 2022 11:49:52 -0700 you wrote:
> 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.
> 
> [...]

Here is the summary with links:
  - [bpf-next,v11,1/5] bpf: Parameterize task iterators.
    https://git.kernel.org/bpf/bpf-next/c/f0d74c4da1f0
  - [bpf-next,v11,2/5] bpf: Handle bpf_link_info for the parameterized task BPF iterators.
    https://git.kernel.org/bpf/bpf-next/c/21fb6f2aa389
  - [bpf-next,v11,3/5] bpf: Handle show_fdinfo for the parameterized task BPF iterators
    https://git.kernel.org/bpf/bpf-next/c/2c4fe44fb020
  - [bpf-next,v11,4/5] selftests/bpf: Test parameterized task BPF iterators.
    https://git.kernel.org/bpf/bpf-next/c/b3e1331eb925
  - [bpf-next,v11,5/5] bpftool: Show parameters of BPF task iterators.
    https://git.kernel.org/bpf/bpf-next/c/6bdb6d6be019

You are awesome, thank you!