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Subject: Re: [PATCH] x86: Add an explicit barrier() to clflushopt()
To: Chris Wilson <chris@chris-wilson.co.uk>,
        Andy Lutomirski <luto@amacapital.net>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Ross Zwisler <ross.zwisler@linux.intel.com>,
        "H . Peter Anvin" <hpa@linux.intel.com>,
        Borislav Petkov <bp@alien8.de>, Brian Gerst <brgerst@gmail.com>,
        Denys Vlasenko <dvlasenk@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>, Imre Deak <imre.deak@intel.com>,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        DRI <dri-devel@lists.freedesktop.org>
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From: "H. Peter Anvin" <hpa@zytor.com>
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Date: Thu, 7 Jan 2016 13:05:35 -0800
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On 01/07/16 11:44, Chris Wilson wrote:
> 
> Now I feel silly. Looking at the .s, there is no difference with the
> addition of the barrier to clflush_cache_range(). And sure enough
> letting the test run for longer, we see a failure. I fell for a placebo.
> 
> The failing assertion is always on the last cacheline and is always one
> value behind. Oh well, back to wondering where we miss the flush.
> -Chris
> 

Could you include the assembly here?

	-hpa