diff options
Diffstat (limited to 'absl/container/internal/hashtablez_sampler.h')
| -rw-r--r-- | absl/container/internal/hashtablez_sampler.h | 16 |
1 files changed, 3 insertions, 13 deletions
diff --git a/absl/container/internal/hashtablez_sampler.h b/absl/container/internal/hashtablez_sampler.h index 0fd9349f..6738786c 100644 --- a/absl/container/internal/hashtablez_sampler.h +++ b/absl/container/internal/hashtablez_sampler.h @@ -67,7 +67,8 @@ struct HashtablezInfo : public profiling_internal::Sample<HashtablezInfo> { // Puts the object into a clean state, fills in the logically `const` members, // blocking for any readers that are currently sampling the object. - void PrepareForSampling() ABSL_EXCLUSIVE_LOCKS_REQUIRED(init_mu); + void PrepareForSampling(size_t inline_element_size_value) + ABSL_EXCLUSIVE_LOCKS_REQUIRED(init_mu); // These fields are mutated by the various Record* APIs and need to be // thread-safe. @@ -82,18 +83,6 @@ struct HashtablezInfo : public profiling_internal::Sample<HashtablezInfo> { std::atomic<size_t> hashes_bitwise_xor; std::atomic<size_t> max_reserve; - // One could imagine that inline_element_size could be non-atomic, since it - // *almost* follows the rules for the fields that are set by - // `PrepareForSampling`. However, TSAN reports a race (see b/207323922) in - // which - // A: Thread 1: Register() returns, unlocking init_mu. - // B: Thread 2: Iterate() is called, locking init_mu. - // C: Thread 1: inlined_element_size is stored. - // D: Thread 2: inlined_element_size is accessed (a race). - // A simple solution is to make inline_element_size atomic so that we treat it - // at as we do the other atomic fields. - std::atomic<size_t> inline_element_size; - // All of the fields below are set by `PrepareForSampling`, they must not be // mutated in `Record*` functions. They are logically `const` in that sense. // These are guarded by init_mu, but that is not externalized to clients, @@ -103,6 +92,7 @@ struct HashtablezInfo : public profiling_internal::Sample<HashtablezInfo> { absl::Time create_time; int32_t depth; void* stack[kMaxStackDepth]; + size_t inline_element_size; // How big is the slot? }; inline void RecordRehashSlow(HashtablezInfo* info, size_t total_probe_length) { |