Re: [cpuops cmpxchg double V2 1/4] Generic support for this_cpu_cmpxchg_double

From: Pekka Enberg
Date: Fri Feb 25 2011 - 08:09:32 EST

On Fri, Jan 21, 2011 at 09:13:41AM -0800, H. Peter Anvin wrote:
We could do cmpxchg with a structure... the problem with a lon int
type is that Cristoph ran into bugs with __int128 on 64 bits.

On 01/21/2011 09:19 AM, Tejun Heo wrote:
But, IIRC, the problem with int128 was with passing it as parameter
and return value. We don't have to do that. We'll be just using it
as a data storage / container type. Or even that is broken?

On 1/24/11 8:01 AM, H. Peter Anvin wrote:
Well, part of the point was to pass in registers.

No idea on the data storage type.

Ping? The current situation is that we're unable to merge a perfectly good SLUB performance optimization because we can't seem to agree on the this_cpu_cmpxchg_double() API.

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