Potential Race Condition in Memory Allocator Initialization

[han-ian]

Code:
https://github.com/deepseek-ai/3FS/blob/main/src/memory/common/GlobalMemoryAllocator.cc#L76C2-L76C4

Issue Details:
Instruction reordering: gAllocatorInited = true may execute before std::call_once
Memory visibility: gAllocatorInited is not atomic, causing visibility issues across cores
Race condition: Other threads may see gAllocatorInited = true while the allocator is still uninitialized

May be this is an issue.