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authorAndi Shyti <andi.shyti@linux.intel.com>2026-08-22 14:19:12 +0200
committerAndi Shyti <andi.shyti@linux.intel.com>2026-08-22 14:19:34 +0200
commitd576a9561a1c80ae593539fb0ce0743d66825ac2 (patch)
tree68f6de7e06b350afa42edeea2f7f33f086014597 /tools/lib/perf/TODO
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Merge tag 'rust-i2c-for-7.3' into i2c/i2cgrafted
i2c: rust: mark I2cAdapter methods as inline A single cleanup for the Rust I2C abstractions, targeting 7.3. `I2cAdapter::get`, `inc_ref`, and `dec_ref` are trivial wrappers around `i2c_get_adapter`/`i2c_put_adapter` and were showing up as their own symbols in the build. Mark them `#[inline]` so they get folded into their callers instead. Signed-off-by: Igor Korotin <igor.korotin@linux.dev> * tag 'rust-i2c-for-7.3': i2c: rust: mark I2cAdapter methods as inline
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+Future ABI changes
+==================
+
+This file collects items that require a libperf ABI bump. Each entry
+should describe the current limitation, the desired end state, and the
+scope of the change so that a future ABI revision can batch them
+together.
+
+1. Widen struct perf_cpu.cpu from int16_t to int
+ - Current limit: 32767 CPUs. No architecture exceeds this today
+ (x86_64 max is 8192, arm64 is 4096), but NR_CPUS limits keep
+ growing. perf clamps to INT16_MAX in set_max_cpu_num() as a
+ safety net.
+ - Code simplification: the int16_t forces defensive truncation
+ checks at every boundary where a wider CPU index (int from
+ sample->cpu, al->cpu, etc.) is narrowed into struct perf_cpu.
+ Without these checks, values > 32767 silently wrap to negative
+ numbers (two's complement), bypassing bounds validation.
+ Widening to int eliminates this entire class of silent
+ truncation bugs and removes the need for the INT16_MAX clamp
+ in set_max_cpu_num().
+ - Scope: struct perf_cpu is embedded everywhere — perf_cpu_map__cpu(),
+ perf_cpu_map__min(), perf_cpu_map__max(), perf_cpu_map__has(), the
+ for_each_cpu macros, and all internal callers. The perf_cpu_map
+ internal array (RC_CHK_ACCESS(map)->map[]) stores struct perf_cpu
+ directly. Widening changes the struct layout and every function
+ that returns or accepts struct perf_cpu by value.
+ - Migration: bump LIBPERF version in libperf.map, audit all
+ sizeof(struct perf_cpu) assumptions, update perf.data
+ serialization if needed.