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

From: H. Peter Anvin
Date: Thu Jan 07 2016 - 17:32:58 EST


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