Three new kfuncs, namely bpf_iter_cpumask_{new,next,destroy}, have been
added for the new bpf_iter_cpumask functionality. These kfuncs enable the
iteration of percpu data, such as runqueues, system_group_pcpu, and more.
In our specific use case, we leverage the cgroup iterator to traverse
percpu data, subsequently exposing it to userspace through a seq file.
Refer to the test cases in patch #2 for further context and examples.
Changes:
- v2 -> v3:
- Define KF_RCU_PROTECTED for bpf_iter_cpumask_new (Alexei)
- Code improvement in selftests
- Fix build error in selftest due to CONFIG_PSI=n
reported by kernel test robot <lkp@xxxxxxxxx>
- v1 -> v2:
- Avoid changing cgroup subsystem (Tejun)
- Remove bpf_cpumask_set_from_pid(), and use bpf_cpumask_copy()
instead (Tejun)
- Use `int cpu;` field in bpf_iter_cpumask_kern (Andrii)
- bpf: Add new bpf helper bpf_for_each_cpu
https://lwn.net/ml/bpf/20230801142912.55078-1-laoar.shao@xxxxxxxxx/
Yafang Shao (3):
bpf: Add bpf_iter_cpumask kfuncs
bpf, doc: Add document for cpumask iter
selftests/bpf: Add selftests for cpumask iter
Documentation/bpf/cpumasks.rst | 17 +++
kernel/bpf/cpumask.c | 69 +++++++++
tools/testing/selftests/bpf/config | 1 +
.../selftests/bpf/prog_tests/cpumask_iter.c | 134 ++++++++++++++++++
.../selftests/bpf/progs/cpumask_common.h | 3 +
.../selftests/bpf/progs/test_cpumask_iter.c | 56 ++++++++
6 files changed, 280 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/cpumask_iter.c
create mode 100644 tools/testing/selftests/bpf/progs/test_cpumask_iter.c
--
2.39.1
