Subject: Re: [PATCH 5/7] [RFC] force 32-byte aligned kmallocs

From: Benjamin Herrenschmidt <[email-masked]>
Date: Fri, 20 May 2011 10:36:09 +1000

On Wed, 2011-05-18 at 16:24 -0500, Eric Van Hensbergen wrote:
> For BGP, it is convenient for 'kmalloc' to come back with 32-byte
> aligned units for torus DMA
> 
> Signed-off-by: Eric Van Hensbergen <[email-masked]>
> ---
>  arch/powerpc/include/asm/page_32.h |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/page_32.h b/arch/powerpc/include/asm/page_32.h
> index 68d73b2..fb0a7ae 100644
> --- a/arch/powerpc/include/asm/page_32.h
> +++ b/arch/powerpc/include/asm/page_32.h
> @@ -9,7 +9,7 @@
>  
>  #define VM_DATA_DEFAULT_FLAGS	VM_DATA_DEFAULT_FLAGS32
>  
> -#ifdef CONFIG_NOT_COHERENT_CACHE
> +#if defined(CONFIG_NOT_COHERENT_CACHE) || defined(CONFIG_BGP)
>  #define ARCH_DMA_MINALIGN	L1_CACHE_BYTES
>  #endif

Is DMA cache coherent on BG/P ? That's odd for a 4xx base :-)

Cheers,
Ben.