[ovs-dev] [PATCH] datapath-windows: Add Windows thread atomic APIs for x64 binaries.

[Ben Pfaff]

On Mon, Mar 28, 2016 at 09:11:24PM +0000, Sorin Vinturis wrote:
> Hi Guru,
> 
> I have verified the ovs-atomic-msvc.h header and all the defined
> macros and functions have 32-bit and 64-bit correspondent. All 64-bit
> macros use InterlockedXXX functions that are atomic:
> InterlockedExchangeNoFence64, InterlockedExchange64,
> InterlockedCompareExchange64, _InterlockedExchangeAdd64,
> InterlockedAnd64, InterlockedOr64, InterlockedXor64. I have ran
> test-atomic.c unit tests, on both 32-bit and 64-bit platforms, and all
> the tests are verified.
> 
> I also tested the 64-bit build on Hyper-V and it is stable.
> 
> Is there a reason why we should not use ovs-atomic-msvc APIs for 64-bit builds?

ovs-atomic-msvc.h seems pretty oriented toward a 32-bit build.  At
least, I really doubt MSVC would break 64-bit reads and writes into two
32-bit reads and writes on 64-bit builds, which is what the code in the
header currently assumes.  You don't want to update it to handle 64-bit
builds differently?  I guess that these would be optimizations, but they
seem straightforward.