[PATCH] powerpc/mm: Lockless get_user_pages_fast()

[Kumar Gala]

On Jul 29, 2008, at 10:37 PM, Benjamin Herrenschmidt wrote:

> From: Nick Piggin <npiggin at suse.de>
>
> Implement lockless get_user_pages_fast for powerpc.  Page table  
> existence
> is guaranteed with RCU, and speculative page references are used to  
> take a
> reference to the pages without having a prior existence guarantee on  
> them.
>
> Signed-off-by: Nick Piggin <npiggin at suse.de>
> Signed-off-by: Dave Kleikamp <shaggy at linux.vnet.ibm.com>
> Acked-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> Cc: Paul Mackerras <paulus at samba.org>
> Cc: Hugh Dickins <hugh at veritas.com>
> Cc: "Paul E. McKenney" <paulmck at us.ibm.com>
> Cc: Peter Zijlstra <a.p.zijlstra at chello.nl>
> Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
> ---
>
> I'm going to merge this, sending it to the list for reference, it was
> in -mm for some time , minus some changes/fixes I did to solve  
> conflicts
> with the new multiple huge page sizes.
>
> Index: linux-work/arch/powerpc/Kconfig
> ===================================================================
> --- linux-work.orig/arch/powerpc/Kconfig	2008-07-30  
> 13:17:06.000000000 +1000
> +++ linux-work/arch/powerpc/Kconfig	2008-07-30 13:27:40.000000000  
> +1000
> @@ -42,6 +42,9 @@ config GENERIC_HARDIRQS
> 	bool
> 	default y
>
> +config HAVE_GET_USER_PAGES_FAST
> +	def_bool PPC64
> +
> config HAVE_SETUP_PER_CPU_AREA
> 	def_bool PPC64

what's ppc64 specific here?

- k