Re: [PATCH bpf-next v5 0/2] Add wakeup_source iterators

[Samuel Wu]

On Wed, Feb 25, 2026 at 1:08 PM Samuel Wu <wusamuel@xxxxxxxxxx> wrote:
>
> This patch series introduces BPF iterators for wakeup_source, enabling
> BPF programs to efficiently traverse a device's wakeup sources.
>
> Currently, inspecting wakeup sources typically involves reading interfaces
> like /sys/class/wakeup/* or debugfs. The repeated syscalls to query the
> sysfs nodes is inefficient, as there can be hundreds of wakeup_sources, and
> each wakeup source have multiple stats, with one sysfs node per stat.
> debugfs is unstable and insecure.
>
> The iterators utilize pre-existing wakeup_sources_walk_* functions to
> traverse over the SRCU that backs the list of wakeup_sources.
>
> Changes in v5:
>  - Add CORE definitions for *__local variables to fix s390 build per bpf-ci
>  - v4 link: https://lore.kernel.org/all/20260211235055.239024-1-wusamuel@xxxxxxxxxx/
>
> Changes in v4:
>  - Proper init of variables in ws_iter_check_sleep_times() test per bpf-ci
>  - Remove PM patch since it's already part of rebase
>  - v3 link: https://lore.kernel.org/all/20260124012133.2451708-1-wusamuel@xxxxxxxxxx/
>
> Changes in v3:
>  - Update wakeup_sources_walk_start() to handle an empty list per bpf-ci
>  - Simplify read of a struct's field in BPF program selftest per Andrii
>  - Drop open coded iterators for wakeup_sources
>  - Fix condition from !get_ws_iter_stream to get_ws_iter_stream in selftest
>  - Read event_count instead of wakeup_count in selftest
>  - v2 link: https://lore.kernel.org/all/20260108225523.3268383-1-wusamuel@xxxxxxxxxx/
>
> Changes in v2:
>  - Guard BPF Makefile with CONFIG_PM_SLEEP to fix build errors
>  - Update copyright from 2025 to 2026
>  - v1 link: https://lore.kernel.org/all/20251204025003.3162056-1-wusamuel@xxxxxxxxxx/
>
>
> Samuel Wu (2):
>   bpf: Add wakeup_source iterator
>   selftests/bpf: Add tests for wakeup_sources
>
>  kernel/bpf/Makefile                           |   3 +
>  kernel/bpf/wakeup_source_iter.c               | 103 ++++++
>  tools/testing/selftests/bpf/config            |   1 +
>  .../bpf/prog_tests/wakeup_source_iter.c       | 300 ++++++++++++++++++
>  .../selftests/bpf/progs/wakeup_source_iter.c  |  80 +++++
>  5 files changed, 487 insertions(+)
>  create mode 100644 kernel/bpf/wakeup_source_iter.c
>  create mode 100644 tools/testing/selftests/bpf/prog_tests/wakeup_source_iter.c
>  create mode 100644 tools/testing/selftests/bpf/progs/wakeup_source_iter.c
>
> --
> 2.53.0.473.g4a7958ca14-goog
>

Hi Andrii, any thoughts on this patchset? I've addressed your
suggestion from v2 of this patchset regarding selftest, but nothing
fundamental has changed since then.

Thanks!
Sam