[PATCH] x86: Add an explicit barrier() to clflushopt()

[H. Peter Anvin]

On 01/07/16 14:29, H. Peter Anvin wrote:
> 
> I would be very interested in knowing if replacing the final clflushopt
> with a clflush would resolve your problems (in which case the last mb()
> shouldn't be necessary either.)
> 

Nevermind.  CLFLUSH is not ordered with regards to CLFLUSHOPT to the
same cache line.

Could you add a sync_cpu(); call to the end (can replace the final mb())
and see if that helps your case?

        -hpa