This document is outdated, PartitionAlloc is used for all allocations now: https://chromium.googlesource.com/chromium/src/+/ec6b52f91a4cfa3fe28fd7cf2c3662efb1d5

This document is outdated, PartitionAlloc is used for all allocations now: https://chromium.googlesource.com/chromium/src/+/ec6b52f91a4cfa3fe28fd7cf2c3662efb1d55235 https://chromium.googlesource.com/chromium/src/+/ec6b52f91a4... It uses plain os_unfair_lock: https://chromium.googlesource.com/chromium/src.git/+/refs/heads/main/base/allocator/partition_allocator/spinning_mutex.h#51 https://chromium.googlesource.com/chromium/src.git/+/refs/he... EDIT: It also combines os_unfair_lock with manual PAUSE spinning.