Re: RFC: Kernel lock elision for TSX

Benjamin Herrenschmidt
2013-03-24T14:22:14Z

On Sat, 2013-03-23 at 19:00 +0100, Andi Kleen wrote:
> Hi Linux,
>
> Thanks. Other code/design review would be still appreciated, even
> under the current constraints.
>
> > The other comment I have is that since it does touch non-x86 header
> > files etc (although not a lot), you really need to talk to the POWER8
> > people about naming of the thing. Calling it <linux/rtm.h> and having
> > "generic" helpers called _xtest() used by the generic spinlock code
> > sounds a bit suspect.
>
> I can make up another name for _xtest()/_xabort() and linux/rtm.h,
> (any suggestions?)
>
> The basic concepts implemented there should be pretty universal.
> If others have a equivalent of "is this a transaction" and "abort
> this tranction" they can just plug it in. Otherwise they will nop it,
> as it's only hints anyways.
>
> The only things used outside x86 code is _xtest()/_xabort(), can
> remove the rest from linux/*. Without transactions this is all nops.
> The primary interface for the lock code is the much higher level
> elide()/elide_lock_adapt() interface anyways.

Adding Michael Neuling to the CC list, he's probably the LTC person who
is the most familiar with POWER8 TM at the moment.

Cheers,
Ben.

> -Andi
>