[all-commits] [llvm/llvm-project] 01bf29: [sanitizers] Optimize locking StackDepotBase for f...

[Vitaly Buka via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 01bf29b9d04e047096b34acc7e4ad1aff97f1a43
      https://github.com/llvm/llvm-project/commit/01bf29b9d04e047096b34acc7e4ad1aff97f1a43
  Author: Vitaly Buka <vitalybuka at google.com>
  Date:   2023-12-26 (Tue, 26 Dec 2023)

  Changed paths:
    M compiler-rt/lib/sanitizer_common/sanitizer_flat_map.h
    M compiler-rt/lib/sanitizer_common/sanitizer_stackdepotbase.h

  Log Message:
  -----------
  [sanitizers] Optimize locking StackDepotBase for fork (#76280)

Locking StackDepotBase fully is very expensive, as 2^20 buckets needs to
be locked. Not locking, but only unlocking buckets, needed to be
unlocked to avoid deadlocks, increases a chance of data race, when the
value with same hash can be inserted into table twice, but one is lost.
However this is just a small additional memory usage by forked process.