Re: [PATCH 1/2] locking/rwsem: Add CONFIG_RWSEM_SPIN_ON_OWNER

[Davidlohr Bueso]

On Fri, 2014-06-06 at 10:13 -0700, Jason Low wrote:
> On Fri, 2014-06-06 at 08:55 -0700, Davidlohr Bueso wrote:
> > Just like with mutexes (CONFIG_MUTEX_SPIN_ON_OWNER),
> > encapsulate the dependencies for rwsem optimistic spinning.
> > No logical changes here as it continues to depend on both
> > SMP and the XADD algorithm variant.
> > 
> > Signed-off-by: Davidlohr Bueso <davidlohr@xxxxxx>
> > ---
> >  include/linux/rwsem.h  | 4 ++--
> >  kernel/Kconfig.locks   | 4 ++++
> >  kernel/locking/rwsem.c | 2 +-
> >  3 files changed, 7 insertions(+), 3 deletions(-)
> 
> Do we also want to add an #ifdef CONFIG_RWSEM_SPIN_ON_OWNER in
> __init_rwsem() and in the optimistic spinning functions for rwsem-xadd?
> 

Not really, as we conditionally build rwsem-xadd.o based on
CONFIG_RWSEM_XCHGADD_ALGORITHM:

obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
obj-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem-xadd.o

So leaving just SMP is ok there.

> 
> Besides that:
> 
> Acked-by: Jason Low <jason.low2@xxxxxx>
> 

Thanks,
Davidlohr

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