Add a bullet point to the libperf ABI TODO explaining the code
simplification benefit of widening struct perf_cpu.cpu from int16_t
to int: the narrow type forces defensive truncation checks at every
boundary where wider CPU indices are narrowed, and values > 32767
silently wrap to negative numbers (two's complement), bypassing
bounds validation without them.
Acked-by: Ian Rogers <irogers@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
struct perf_cpu.cpu is int16_t, limiting perf to 32767 CPUs. This is
part of the libperf ABI (returned by value from perf_cpu_map__cpu() and
friends), so widening it requires an ABI bump.
Add a comment on the struct definition noting this, and create a TODO
file to collect future ABI changes so they can be batched into a single
version bump.
Cc: Ian Rogers <irogers@google.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
