Re: About spinlock implementation

[mogu via Digitalmars-d-learn]

On Thursday, 1 September 2016 at 07:46:04 UTC, qznc wrote:

I'm not sure I understand rel [0], but raw is too weak. Raw means no sequencing barrier, so

  local_var = protected_value;
  spinlock.unlock();

could be transformed (by compiler or CPU) to

  spinlock.unlock();
  local_var = protected_value;

This effectively makes the access to the protected value unprotected and nullifies the effect of the spinlock.

I find the documentation on MemoryOrder lacking about the semantics of rel. :(

[0] https://dlang.org/library/core/atomic/memory_order.html

Thanks very much. I finally got it. :)