lwn.git - Linux kernel documentation tree maintained by Jonathan Corbet

Age	Commit message (Collapse)	Author
2026-06-10	libperf: Document code simplification case for widening struct perf_cpu	Arnaldo Carvalho de Melo
	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>
2026-06-06	libperf: Document struct perf_cpu int16_t ABI limitation	Arnaldo Carvalho de Melo
	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>