[v3,bpf-next,0/4] bpf: enable task local storage for tracing programs

Message

Song Liu Jan. 28, 2021, 12:19 a.m. UTC

This set enables task local storage for non-BPF_LSM programs.

It is common for tracing BPF program to access per-task data. Currently,
these data are stored in hash tables with pid as the key. In
bcc/libbpftools [1], 9 out of 23 tools use such hash tables. However,
hash table is not ideal for many use case. Task local storage provides
better usability and performance for BPF programs. Please refer to 4/4 for
some performance comparison of task local storage vs. hash table.

Changes v2 => v3:
1. Make the selftest more robust. (Andrii)
2. Small changes with runqslower. (Andrii)
3. Shortern CC list to make it easy for vger.

Changes v1 => v2:
1. Do not allocate task local storage when the task is being freed.
2. Revise the selftest and added a new test for a task being freed.
3. Minor changes in runqslower.

Song Liu (4):
  bpf: enable task local storage for tracing programs
  selftests/bpf: add non-BPF_LSM test for task local storage
  bpf: runqslower: prefer using local vmlimux to generate vmlinux.h
  bpf: runqslower: use task local storage

 include/linux/bpf.h                           |  7 ++
 include/linux/bpf_lsm.h                       | 22 ------
 include/linux/bpf_types.h                     |  2 +-
 include/linux/sched.h                         |  5 ++
 kernel/bpf/Makefile                           |  3 +-
 kernel/bpf/bpf_local_storage.c                | 28 +++++---
 kernel/bpf/bpf_lsm.c                          |  4 --
 kernel/bpf/bpf_task_storage.c                 | 34 +++------
 kernel/fork.c                                 |  5 ++
 kernel/trace/bpf_trace.c                      |  4 ++
 tools/bpf/runqslower/Makefile                 |  5 +-
 tools/bpf/runqslower/runqslower.bpf.c         | 33 +++++----
 .../bpf/prog_tests/task_local_storage.c       | 69 +++++++++++++++++++
 .../selftests/bpf/progs/task_local_storage.c  | 64 +++++++++++++++++
 .../bpf/progs/task_local_storage_exit_creds.c | 32 +++++++++
 15 files changed, 239 insertions(+), 78 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/task_local_storage.c
 create mode 100644 tools/testing/selftests/bpf/progs/task_local_storage.c
 create mode 100644 tools/testing/selftests/bpf/progs/task_local_storage_exit_creds.c

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2.24.1