Re: [PATCH v8 2/6] powerpc: pSeries/Kconfig: Add qspinlock build config

[Pan Xinhui]

å 2016/12/6 09:24, Pan Xinhui åé:
> å 2016/12/6 08:58, Boqun Feng åé:
> > On Mon, Dec 05, 2016 at 10:19:22AM -0500, Pan Xinhui wrote:
> > > pSeries/powerNV will use qspinlock from now on.
> > >
> > > Signed-off-by: Pan Xinhui <xinhui.pan@xxxxxxxxxxxxxxxxxx>
> > > ---
> > >  arch/powerpc/platforms/pseries/Kconfig | 8 ++++++++
> > >  1 file changed, 8 insertions(+)
> > >
> > > diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
> > > index bec90fb..8a87d06 100644
> > > --- a/arch/powerpc/platforms/pseries/Kconfig
> > > +++ b/arch/powerpc/platforms/pseries/Kconfig
> >
> > Why here? Not arch/powerpc/platforms/Kconfig?
> >
> > > @@ -23,6 +23,14 @@ config PPC_PSERIES
> > >      select PPC_DOORBELL
> > >      default y
> > >
> > > +config ARCH_USE_QUEUED_SPINLOCKS
> > > +    default y
> > > +    bool "Enable qspinlock"
> >
> > I think you just enable qspinlock by default for all PPC platforms. I
> > guess you need to put
> >
> >     depends on PPC_PSERIES || PPC_POWERNV
> >
> > here to achieve what you mean in you commit message.
oh, yes, need depends on PPC_PSERIES || PPC_POWERNV.

> yes, another good way.
> I prefer to put it in pseries/Kconfig as same as pv-qspinlocks config.
> when we build nv, it still include pSeries's config anyway.
>
> thanks
> xinhui
>
> > Regards,
> > Boqun
> >
> > > +    help
> > > +      Enabling this option will let kernel use qspinlock which is a kind of
> > > +      fairlock.  It has shown a good performance improvement on x86 and also ppc
> > > +      especially in high contention cases.
> > > +
> > >  config PPC_SPLPAR
> > >      depends on PPC_PSERIES
> > >      bool "Support for shared-processor logical partitions"
> > > --
> > > 2.4.11